High-temperature-resistant hot-melt pressure-sensitive adhesive and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant hot-melt pressure-sensitive adhesive and a preparation method thereof, and relates to the technical field of adhesives. The high-temperature-resistant hot-melt pressure-sensitive adhesive prepared by the invention comprises a thermoplastic elastomer, branched polyolefin, modified tackifying resin and an auxiliary agent, the branched polyolefin is prepared by reaction of 1, 2, 4-cyclohexane trimethyl anhydride, a sulfydryl block polymer and an epoxy polyolefin elastomer, and the sulfydryl block polymer is prepared by reaction of tert-butyl acrylate, 4-vinyl benzyl chloride and potassium thioacetate and then thioacetate removal reaction. The epoxy polyolefin elastomer is prepared from a polyolefin elastomer and m-chloroperoxybenzoic acid through a reaction, the modified tackifying resin is prepared from p-tert-octylphenol formaldehyde resin and a multi-benzene-ring compound through a reaction, the multi-benzene-ring compound is prepared from pyromellitic dianhydride, diethanol amine and epoxy polyisoprene through a reaction, and the heat resistance and cohesiveness of the hot-melt pressure-sensitive adhesive are improved. The invention discloses a manufacturing method of a high-emissivity coating suitable for the surface of a refractory material.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and specifically relates to a high-temperature resistant hot melt pressure-sensitive adhesive and a preparation method thereof. Background Art

[0002] A pressure-sensitive adhesive refers to a type of adhesive that is sensitive to pressure and can be bonded to the adherend with a little finger pressure without the use of solvents or other auxiliary means. The hot melt pressure-sensitive adhesive is the third-generation pressure-sensitive adhesive product after the solvent-based and emulsion-based pressure-sensitive adhesives. Compared with the previous two, the hot melt pressure-sensitive adhesive is solvent-free, which is more conducive to environmental protection and safe production, has high production efficiency, and relatively low production cost.

[0003] The hot melt pressure-sensitive adhesive can adapt to various materials and is widely used in various fields such as carton sealing, box sealing, paper product packaging, beverage bottle labels, waterproof coiled materials, and flexible packaging. However, the viscosity of the existing hot melt pressure-sensitive adhesive is significantly affected by temperature, and there are problems such as poor high-temperature resistance, poor stability, and weak viscosity. Therefore, the present invention has studied and prepared a high-temperature resistant hot melt pressure-sensitive adhesive with excellent high-temperature resistance, stability, and viscosity to solve the above problems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-temperature resistant hot melt pressure-sensitive adhesive and a preparation method thereof.

[0005] A technical solution proposed by the present invention to solve the above technical problem is: a high-temperature resistant hot melt pressure-sensitive adhesive, comprising a thermoplastic elastomer, a branched polyolefin, a modified tackifying resin, and an additive; the thermoplastic elastomer includes at least one of SIS, SBS, and SSBR; the branched polyolefin is prepared by reacting 1,2,4-cyclohexanetricarboxylic anhydride, a mercapto-block copolymer, and an epoxy polyolefin elastomer; the modified tackifying resin is prepared by reacting p-tert-octylphenol formaldehyde resin with a polybenzene ring compound.

[0006] Preferably, the SIS is a styrene-isoprene-styrene block copolymer; the SBS is a styrene-butadiene-styrene block copolymer; the solution-polymerized styrene-butadiene rubber SSBR.

[0007] Preferably, the mercapto-block copolymer is prepared by reacting a mercapto-block copolymer matrix to remove thioacetate; the mercapto-block copolymer matrix is prepared by reacting tert-butyl acrylate, 4-vinylbenzyl chloride, and potassium thioacetate; the epoxy polyolefin elastomer is prepared by reacting a polyolefin elastomer with m-chloroperbenzoic acid.

[0008] Preferably, the polybenzene ring compound is prepared by reacting pyromellitic dianhydride, diethanolamine, and epoxy polyisoprene.

[0009] Preferably, the additive includes an antioxidant and an antioxidant in a mass ratio of 1:0.4 to 0.8; the antioxidant is 2,6-ditert-butyl-p-cresol; the antioxidant is antioxidant 1076.

[0010] Preferably, the preparation method of the high-temperature resistant hot melt pressure-sensitive adhesive includes the following specific steps:

[0011] S1. Under an argon atmosphere, a mercapto-block polymer matrix, N,N-dimethylformamide, n-butylamine, and dithiothreitol are mixed in a mass ratio of 0.2 to 0.3:4:0.6 to 0.62:0.65, heated to 60 to 62 °C, and reacted in the dark for 24 h. The pH is adjusted to 0.8 to 1.2 with hydrochloric acid, centrifuged and dissolved in tetrahydrofuran, rotary evaporated, then precipitated with methanol, and finally dried under vacuum to obtain a mercapto-block polymer;

[0012] S2. Under a nitrogen atmosphere, 1,2,4-cyclohexanetricarboxylic anhydride, the mercapto-block polymer, and N,N-dimethylformamide are mixed, stirred evenly, then heated to 100 to 110 °C, reacted for 3 to 5 h, an epoxy polyolefin elastomer is added, and the reaction continues for 1 to 3 h, and then rotary evaporated to obtain a branched polyolefin;

[0013] S3. Under a nitrogen atmosphere, diethanolamine and N,N-dimethylformamide are mixed in a mass ratio of 8 to 9:10 and stirred evenly to obtain solution A; pyromellitic dianhydride and N,N-dimethylformamide are mixed in a mass ratio of 1 to 2:10 and stirred evenly to obtain solution B. Solution B with a volume 3 to 4 times that of solution A is added dropwise to solution A at a rate of 1 to 3 ml / min. After reacting at room temperature for 3 to 4 h, it is washed with toluene and filtered, and then 0.8 to 0.9 times the mass of pyromellitic dianhydride of epoxy polyisoprene and 0.06 to 0.08 times the mass of pyromellitic dianhydride of triethylamine are added, heated to 100 to 120 °C, reacted for 1 to 2 h, heated to 160 to 180 °C, reacted for 2 to 4 h, and rotary evaporated to obtain a polycyclic aromatic compound;

[0014] S4. p-tert-Octylphenol formaldehyde resin, the polycyclic aromatic compound, concentrated sulfuric acid, and deionized water are mixed in a mass ratio of 20:0.15 to 0.18:0.4, heated to 100 to 110 °C, and formaldehyde with a mass 0.1 to 0.2 times that of p-tert-octylphenol formaldehyde resin is added dropwise at a rate of 1 to 3 ml / min. After reacting for 3 to 4 h, it is heated to 180 to 190 °C, reacted for 2 to 3 h, cooled to 150 to 170 °C, and dehydrated under vacuum to obtain a modified tackifying resin;

[0015] S5. The thermoplastic elastomer, the branched polyolefin, the modified tackifying resin, and the additive are mixed, heated to 150 to 170 °C, stirred at 100 to 200 rpm for 2 to 4 h, and kept warm to remove bubbles to obtain the high-temperature resistant hot melt pressure-sensitive adhesive.

[0016] Preferably, in the above step S1, the preparation method of the mercapto-block polymer matrix is as follows: Under a nitrogen atmosphere, azobisisobutyronitrile, methanol, a chain transfer agent 2-(dodecyltrithiocarbonate)-2-methylpropionic acid, and tert-butyl acrylate are mixed in a mass ratio of 0.04-0.06:6:0.5-0.6:20-30, stirred evenly, heated to 62-66°C, and reacted for 12-16 h. 4-vinylbenzyl chloride with a mass 0.32-0.36 times that of tert-butyl acrylate and tetrahydrofuran with a mass 0.2-0.6 times that of tert-butyl acrylate are added, heated to 70-72°C, and reacted for 24 h. Rotary evaporation is carried out at 40-42°C, and then methanol precipitation is carried out 3-5 times. N-methylpyrrolidone with a mass 8-10 times that of tert-butyl acrylate and potassium thioacetate with a mass 0.14-0.17 times that of tert-butyl acrylate are added, stirred and dissolved, and reacted at room temperature for 24 h. Then deionized water precipitation is carried out 3-5 times, and vacuum drying is carried out at 60-62°C to obtain the mercapto-block polymer matrix.

[0017] Preferably, in the above step S2, the preparation method of the epoxy polyolefin elastomer is as follows: The polyolefin elastomer, m-chloroperbenzoic acid, and dichloromethane are mixed in a mass ratio of 1:1.2-1.5:50, the pH is adjusted to 7-8 with sodium bicarbonate, reacted at room temperature for 6-8 h, quenched with sodium thiosulfate and precipitated with methanol, filtered by suction and dried to obtain the epoxy polyolefin elastomer.

[0018] Preferably, in the above step S2, the mass ratio of 1,2,4-cyclohexanetricarboxylic anhydride, the mercapto-block polymer, N,N-dimethylformamide, and the epoxy polyolefin elastomer is 0.6-1:1:3-5:6-10.

[0019] Preferably, in the above step S3, the preparation method of the epoxy polyisoprene is as follows: The polyisoprene and dichloromethane are mixed in a mass ratio of 1:20-30, stirred evenly, and a 3-chloroperbenzoic acid solution with a mass 4-8 times that of the polyisoprene is added dropwise at a rate of 1-3 ml / min. The mass ratio of 3-chloroperbenzoic acid to dichloromethane in the 3-chloroperbenzoic acid solution is 1:8-10. After reacting for 3-4 h, methanol is added for precipitation, filtered by suction and vacuum dried at 50-60°C to obtain the epoxy polyisoprene.

[0020] Preferably, in the above step S5, the mass ratio of the thermoplastic elastomer, the branched polyolefin, the modified tackifying resin, and the additive is 30-50:20-30:20-30:1-4.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0022] The high-temperature resistant hot melt pressure-sensitive adhesive prepared by the present invention comprises a thermoplastic elastomer, a branched polyolefin, a modified tackifying resin, and an additive;

[0023] The branched polyolefin is prepared by reacting 1,2,4-cyclohexanetricarboxylic anhydride, a mercapto-block polymer, and an epoxy polyolefin elastomer. The mercapto-block polymer is prepared by reacting tert-butyl acrylate, 4-vinylbenzyl chloride, and potassium thioacetate and then removing thioacetate. The epoxy polyolefin elastomer is prepared by reacting a polyolefin elastomer with m-chloroperoxybenzoic acid. The polyolefin elastomer with an epoxy structure, 1,2,4-cyclohexanetricarboxylic anhydride, and the mercapto-block polymer are used to form a branched polyolefin with a hyperbranched structure and a polyester structure, with the mercapto-block polymer as the crosslinking center. When added to a hot-melt pressure-sensitive adhesive, this structure enables the branched polyolefin to disperse more uniformly in the hot-melt pressure-sensitive adhesive and form strong chemical bonds with other components, not only effectively improving the high-temperature resistance but also enhancing the adhesiveness;

[0024] The modified tackifying resin is prepared by reacting p-tert-octylphenol formaldehyde resin with a polycyclic aromatic compound. The polycyclic aromatic compound is prepared by reacting pyromellitic dianhydride, diethanolamine, and epoxy polyisoprene. By introducing a rigid benzene ring and a flexible chain segment into the tackifying resin, the rigid chain segment enhances the cohesion, and the flexible chain segment reduces the resin softening point, improving the compatibility with the thermoplastic elastomer and enhancing the adhesiveness; The active groups at the ends of the modified tackifying resin can also react with the branched polyolefin, further enhancing the interaction between components and making the overall structure more compact, thereby further improving the heat resistance and adhesiveness of the hot-melt pressure-sensitive adhesive; The rigid benzene ring structure in the modified tackifying resin can effectively resist the movement of molecular chains at high temperatures, slowing down the flow of the thermoplastic elastomer and the branched polyolefin, enabling the hot-melt pressure-sensitive adhesive to maintain good stability and adhesive strength at high temperatures. Specific embodiments

[0025] The present invention will be specifically described below through examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention. Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art.

[0026] The polyisoprene used in the specific embodiments of the present invention was purchased from Shandong Yilai New Material Technology Development Co., Ltd., with a CAS of 9003-31-0; the polyolefin elastomer was purchased from Wenzhou Longlij Chemical Co., Ltd.; the thermoplastic elastomer

[0027] To more clearly illustrate the method provided by the present invention, it is described in detail through the following examples. The test methods for each index of the high-temperature resistant hot-melt pressure-sensitive adhesives prepared in the examples and comparative examples are as follows:

[0028] High-temperature resistance: The high-temperature resistant hot-melt pressure-sensitive adhesive was tested for high-temperature resistance with reference to GB / T 2423.22.

[0029] Viscosity: The high-temperature resistant hot melt pressure-sensitive adhesive was subjected to viscosity testing with reference to GB / T 3660.

[0030] Shear strength: The high-temperature resistant hot melt pressure-sensitive adhesive was subjected to shear strength testing with reference to GB / T 7124.

[0031] Example 1

[0032] In this example, the preparation method of the high-temperature resistant hot melt pressure-sensitive adhesive is as follows:

[0033] S1. Under a nitrogen atmosphere, azobisisobutyronitrile, methanol, 2-(dodecyltrithiocarbonate)-2-methylpropanoic acid, and tert-butyl acrylate were mixed in a mass ratio of 0.04:6:0.5:20, stirred evenly, heated to 62 °C, and reacted for 12 h. 4-vinylbenzyl chloride with a mass 0.32 times that of tert-butyl acrylate and tetrahydrofuran with a mass 0.2 times that of tert-butyl acrylate were added, heated to 70 °C, and reacted for 24 h. Rotary evaporation was carried out at 40 °C, and then precipitation with methanol was carried out 3 times. N-methylpyrrolidone with a mass 8 times that of tert-butyl acrylate and potassium thioacetate with a mass 0.14 times that of tert-butyl acrylate were added. After stirring and dissolving, the reaction was carried out at room temperature for 24 h, and then precipitation with deionized water was carried out 3 times. Vacuum drying was carried out at 60 °C to obtain a thiol-block polymer matrix; Under an argon atmosphere, the thiol-block polymer matrix, N,N-dimethylformamide, n-butylamine, and dithiothreitol were mixed in a mass ratio of 0.2:4:0.6:0.65, heated to 60 °C, and reacted in the dark for 24 h. The pH was adjusted to 0.8 with hydrochloric acid, centrifuged and dissolved in tetrahydrofuran, rotary evaporated, and then precipitated with methanol. Finally, vacuum drying was carried out to obtain a thiol-block polymer;

[0034] S2. The polyolefin elastomer, m-chloroperbenzoic acid, and dichloromethane were mixed in a mass ratio of 1:1.2:50, the pH was adjusted to 7 with sodium bicarbonate, and the reaction was carried out at room temperature for 6 h. It was quenched with sodium thiosulfate and precipitated with methanol, filtered by suction and dried to obtain an epoxy polyolefin elastomer; Under a nitrogen atmosphere, 1,2,4-cyclohexanetricarboxylic anhydride, the thiol-block polymer, and N,N-dimethylformamide were mixed and stirred evenly. Then, it was heated to 100 °C and reacted for 3 - 5 h. The epoxy polyolefin elastomer was added, and the mass ratio of 1,2,4-cyclohexanetricarboxylic anhydride, the thiol-block polymer, N,N-dimethylformamide, and the epoxy polyolefin elastomer was 0.6:1:3:6. The reaction was continued for 1 h, and rotary evaporation was carried out to obtain a branched polyolefin;

[0035] S3. Mix polyisoprene and dichloromethane at a mass ratio of 1:20. After stirring evenly, dropwise add a 3-chloroperoxybenzoic acid solution that is 4 times the mass of polyisoprene at a rate of 1 ml / min. The mass ratio of 3-chloroperoxybenzoic acid to dichloromethane in the 3-chloroperoxybenzoic acid solution is 1:8. After reacting for 3 h, add methanol to precipitate, filter by suction, and dry in vacuum at 50 °C to obtain epoxy polyisoprene; under a nitrogen atmosphere, mix diethanolamine and N,N-dimethylformamide at a mass ratio of 8:10 and stir evenly to obtain solution A; mix pyromellitic dianhydride and N,N-dimethylformamide at a mass ratio of 1:10 and stir evenly to obtain solution B. Dropwise add solution B that is 3 times the volume of solution A to solution A at a rate of 1 ml / min. After reacting at room temperature for 3 h, wash with toluene and filter, then add epoxy polyisoprene that is 0.8 times the mass of pyromellitic dianhydride and triethylamine that is 0.06 times the mass of pyromellitic dianhydride, heat up to 100 °C, react for 1 h, heat up to 160 °C, react for 2 h, and perform rotary evaporation to obtain a multi-benzene ring compound;

[0036] S4. Mix p-tert-octylphenol formaldehyde resin, multi-benzene ring compound, concentrated sulfuric acid and deionized water at a mass ratio of 20:0.15:0.4. Heat up to 100 °C, dropwise add formaldehyde that is 0.1 times the mass of p-tert-octylphenol formaldehyde resin at a rate of 1 ml / min. After reacting for 3 h, heat up to 180 °C, react for 2 h, cool down to 150 - 170 °C, and dehydrate under vacuum to obtain a modified tackifying resin;

[0037] S5. Mix thermoplastic elastomer SIS, branched polyolefin, modified tackifying resin and additives at a mass ratio of 30:20:20:1. The additives are antioxidant 2,6-ditert-butyl-p-cresol and antioxidant antioxidant 1076 with a mass ratio of 1:0.4. Heat up to 150 °C, stir at 100 rpm for 2 h, keep warm to remove bubbles, and obtain a high-temperature resistant hot melt pressure-sensitive adhesive.

[0038] Example 2

[0039] In this example, the preparation method of the high-temperature resistant hot melt pressure-sensitive adhesive is as follows:

[0040] S1. Under a nitrogen atmosphere, azobisisobutyronitrile, methanol, 2-(dodecyltrithiocarbonate)-2-methylpropanoic acid, and tert-butyl acrylate were mixed at a mass ratio of 0.05:6:0.55:25, stirred evenly, heated to 64 °C, and reacted for 14 h. 4-vinylbenzyl chloride at 0.34 times the mass of tert-butyl acrylate and tetrahydrofuran at 0.4 times the mass of tert-butyl acrylate were added, heated to 71 °C, and reacted for 24 h. Rotary evaporation was carried out at 41 °C, followed by precipitation with methanol 4 times. N-methylpyrrolidone at 9 times the mass of tert-butyl acrylate and potassium thioacetate at 0.16 times the mass of tert-butyl acrylate were added, stirred and dissolved, and reacted at room temperature for 24 h. Then precipitation with deionized water was carried out 4 times, and vacuum drying was carried out at 61 °C to obtain a thiol-block polymer matrix; Under an argon atmosphere, the thiol-block polymer matrix, N,N-dimethylformamide, n-butylamine, and dithiothreitol were mixed at a mass ratio of 0.25:4:0.61:0.65, heated to 61 °C, and reacted in the dark for 24 h. The pH was adjusted to 1 with hydrochloric acid, centrifuged, dissolved in tetrahydrofuran, rotary evaporated, and then precipitated with methanol. Finally, vacuum drying was carried out to obtain a thiol-block polymer;

[0041] S2. Polyolefin elastomer, m-chloroperoxybenzoic acid, and dichloromethane were mixed at a mass ratio of 1:1.4:50, the pH was adjusted to 7.5 with sodium bicarbonate, and the reaction was carried out at room temperature for 7 h. It was quenched with sodium thiosulfate and precipitated with methanol, filtered by suction and dried to obtain an epoxy polyolefin elastomer; Under a nitrogen atmosphere, 1,2,4-cyclohexanetricarboxylic anhydride, the thiol-block polymer, and N,N-dimethylformamide were mixed, stirred evenly, heated to 105 °C, and reacted for 4 h. The epoxy polyolefin elastomer was added, and the mass ratio of 1,2,4-cyclohexanetricarboxylic anhydride, the thiol-block polymer, N,N-dimethylformamide, and the epoxy polyolefin elastomer was 0.8:1:4:8, and the reaction was continued for 2 h, followed by rotary evaporation to obtain a branched polyolefin;

[0042] S3. Mix polyisoprene and dichloromethane at a mass ratio of 1:25. After stirring evenly, dropwise add a 3-chloroperbenzoic acid solution that is 6 times the mass of polyisoprene at a rate of 2 ml / min. The mass ratio of 3-chloroperbenzoic acid to dichloromethane in the 3-chloroperbenzoic acid solution is 1:9. After reacting for 3.5 h, add methanol to precipitate, filter by suction, and dry in vacuum at 55 °C to obtain epoxy polyisoprene; under a nitrogen atmosphere, mix diethanolamine and N,N-dimethylformamide at a mass ratio of 8.5:10, and stir evenly to obtain solution A; mix pyromellitic dianhydride and N,N-dimethylformamide at a mass ratio of 1.5:10, and stir evenly to obtain solution B. Dropwise add solution B that is 3.5 times the volume of solution A to solution A at a rate of 2 ml / min. After reacting at room temperature for 3.5 h, wash with toluene and filter, then add epoxy polyisoprene that is 0.85 times the mass of pyromellitic dianhydride and triethylamine that is 0.07 times the mass of pyromellitic dianhydride, heat up to 110 °C, react for 1.5 h, heat up to 170 °C, react for 3 h, and perform rotary evaporation to obtain a multi-benzenoid compound;

[0043] S4. Mix p-tert-octylphenol formaldehyde resin, multi-benzenoid compound, concentrated sulfuric acid and deionized water at a mass ratio of 20:0.16:0.4. Heat up to 150 °C, dropwise add formaldehyde that is 0.15 times the mass of p-tert-octylphenol formaldehyde resin at a rate of 2 ml / min. After reacting for 3.5 h, heat up to 185 °C, react for 2.5 h, cool down to 160 °C, and dehydrate under vacuum to obtain a modified tackifying resin;

[0044] S5. Mix thermoplastic elastomer SBS, branched polyolefin, modified tackifying resin and additives at a mass ratio of 40:25:25:3. The additives are antioxidant 2,6-ditert-butyl-p-cresol and antioxidant antioxidant 1076 at a mass ratio of 1:0.6. Heat up to 160 °C, stir at 150 rpm for 3 h, keep warm and remove bubbles to obtain a high-temperature resistant hot melt pressure-sensitive adhesive.

[0045] Example 3

[0046] In this example, the preparation method of the high-temperature resistant hot melt pressure-sensitive adhesive is as follows:

[0047] S1. Under a nitrogen atmosphere, azobisisobutyronitrile, methanol, 2-(dodecyltrithiocarbonate)-2-methylpropanoic acid, and tert-butyl acrylate were mixed at a mass ratio of 0.06:6:0.6:30, stirred evenly, heated to 66 °C, and reacted for 16 h. 4-vinylbenzyl chloride at 0.36 times the mass of tert-butyl acrylate and tetrahydrofuran at 0.6 times the mass of tert-butyl acrylate were added, heated to 72 °C, and reacted for 24 h. Rotary evaporation was carried out at 42 °C, followed by precipitation with methanol 5 times. N-methylpyrrolidone at 10 times the mass of tert-butyl acrylate and potassium thioacetate at 0.17 times the mass of tert-butyl acrylate were added. After stirring and dissolving, the reaction was carried out at room temperature for 24 h, followed by precipitation with deionized water 5 times, and vacuum drying at 62 °C to obtain a thiol-block polymer matrix; Under an argon atmosphere, the thiol-block polymer matrix, N,N-dimethylformamide, n-butylamine, and dithiothreitol were mixed at a mass ratio of 0.3:4:0.62:0.65, heated to 62 °C, and reacted in the dark for 24 h. The pH was adjusted to 1.2 with hydrochloric acid, centrifuged and dissolved in tetrahydrofuran, rotary evaporated, followed by precipitation with methanol, and finally vacuum dried to obtain a thiol-block polymer;

[0048] S2. Polyolefin elastomer, m-chloroperoxybenzoic acid, and dichloromethane were mixed at a mass ratio of 1:1.5:50, the pH was adjusted to 8 with sodium bicarbonate, and the reaction was carried out at room temperature for 8 h. It was quenched with sodium thiosulfate and precipitated with methanol, filtered by suction and dried to obtain an epoxy polyolefin elastomer; Under a nitrogen atmosphere, 1,2,4-cyclohexanetricarboxylic anhydride, the thiol-block polymer, and N,N-dimethylformamide were mixed, stirred evenly, heated to 110 °C, and reacted for 5 h. The epoxy polyolefin elastomer was added, and the mass ratio of 1,2,4-cyclohexanetricarboxylic anhydride, the thiol-block polymer, N,N-dimethylformamide, and the epoxy polyolefin elastomer was 1:1:5:10, and the reaction was continued for 3 h, followed by rotary evaporation to obtain a branched polyolefin;

[0049] S3. Mix polyisoprene and dichloromethane at a mass ratio of 1:30. After stirring evenly, dropwise add a 3-chloroperoxybenzoic acid solution that is 8 times the mass of polyisoprene at a rate of 3 ml / min. The mass ratio of 3-chloroperoxybenzoic acid to dichloromethane in the 3-chloroperoxybenzoic acid solution is 1:10. After reacting for 4 h, add methanol to precipitate, filter by suction, and dry in vacuum at 60 °C to obtain epoxy polyisoprene; under a nitrogen atmosphere, mix diethanolamine and N,N-dimethylformamide at a mass ratio of 9:10, and stir evenly to prepare solution A; mix pyromellitic dianhydride and N,N-dimethylformamide at a mass ratio of 2:10, and stir evenly to prepare solution B. Dropwise add solution B that is 4 times the volume of solution A to solution A at a rate of 3 ml / min. After reacting at room temperature for 4 h, wash with toluene and filter, then add epoxy polyisoprene that is 0.9 times the mass of pyromellitic dianhydride and triethylamine that is 0.08 times the mass of pyromellitic dianhydride, heat up to 120 °C, react for 2 h, heat up to 180 °C, react for 4 h, and perform rotary evaporation to obtain a polybenzene ring compound;

[0050] S4. Mix p-tert-octylphenol formaldehyde resin, polybenzene ring compound, concentrated sulfuric acid and deionized water at a mass ratio of 20:0.18:0.4. Heat up to 110 °C, dropwise add formaldehyde that is 0.2 times the mass of p-tert-octylphenol formaldehyde resin at a rate of 3 ml / min. After reacting for 4 h, heat up to 190 °C, react for 3 h, cool down to 170 °C, and dehydrate under vacuum to obtain a modified tackifying resin;

[0051] S5. Mix thermoplastic elastomer SSBR, branched polyolefin, modified tackifying resin and additives at a mass ratio of 50:30:30:4. The additive is antioxidant 2,6-ditert-butyl-p-cresol and antioxidant antioxidant 1076 with a mass ratio of 1:0.8. Heat up to 170 °C, stir at 100 - 200 rpm for 4 h, keep warm to remove bubbles, and obtain a high-temperature resistant hot melt pressure-sensitive adhesive.

[0052] Comparative Example 1

[0053] The preparation method of Comparative Example 1 is the same as that of Example 2. The difference between this high-temperature resistant hot melt pressure-sensitive adhesive and that of Example 2 is that the high-temperature resistant hot melt pressure-sensitive adhesive prepared in this comparative example only includes thermoplastic elastomer, epoxy polyolefin elastomer, modified tackifying resin and additives.

[0054] Comparative Example 2

[0055] The preparation method of Comparative Example 2 is the same as that of Example 2. The difference between this high-temperature resistant hot melt pressure-sensitive adhesive and that of Example 2 is that the high-temperature resistant hot melt pressure-sensitive adhesive prepared in this comparative example only includes thermoplastic elastomer, modified tackifying resin and additives.

[0056] Comparative Example 3

[0057] The preparation method of Comparative Example 3 is the same as that of Example 2. The difference between this high-temperature resistant hot melt pressure-sensitive adhesive and that of Example 2 lies in that the modified tackifying resin is prepared by reacting p-tert-octylphenol formaldehyde resin with epoxy polyisoprene.

[0058] Comparative Example 4

[0059] The preparation method of Comparative Example 4 is the same as that of Example 2. The difference between this high-temperature resistant hot melt pressure-sensitive adhesive and that of Example 2 lies in that the modified tackifying resin is only p-tert-octylphenol formaldehyde resin.

[0060] Effect Example

[0061] The following Table 1 shows the performance test results of the high-temperature resistant hot melt pressure-sensitive adhesives prepared in the examples and comparative examples;

[0062] Table 1

[0063]

[0064] From the comparison of the performance data in Table 1, it can be seen that the high-temperature resistant hot melt pressure-sensitive adhesive prepared by the present invention has heat resistance, stability and adhesiveness;

[0065] From the comparison of the experimental data of Example 1, Example 2, Example 3 and Comparative Example 1, Comparative Example 2, it can be found that a branched polyolefin with a hyperbranched structure and a polyester structure is formed by using a polyolefin elastomer with an epoxy structure, 1,2,4-cyclohexanetricarboxylic anhydride and a thiol block polymer as the crosslinking center of the thiol block polymer. When added to the hot melt pressure-sensitive adhesive, this structure enables the branched polyolefin to be more uniformly dispersed in the hot melt pressure-sensitive adhesive and form strong chemical bonds with other components, not only effectively improving the high-temperature resistance, but also enhancing the stability and adhesiveness.

[0066] From the comparison of the experimental data of Example 1, Example 2, Example 3 and Comparative Example 3, Comparative Example 4, it can be found that a polycyclic compound prepared by reacting pyromellitic dianhydride, diethanolamine and epoxy polyisoprene is introduced into the tackifying resin, introducing a rigid benzene ring and a flexible chain segment. The rigid chain segment enhances the cohesion, the flexible chain segment reduces the resin softening point, improves the compatibility with the thermoplastic elastomer, and improves the adhesiveness; the active groups at the ends of the modified tackifying resin can also react with the branched polyolefin, further enhancing the interaction between components and making the overall structure more compact, thereby further improving the heat resistance and adhesiveness of the hot melt pressure-sensitive adhesive; the rigid benzene ring structure in the modified tackifying resin can effectively resist the movement of molecular chains at high temperatures, slow down the flow of the thermoplastic elastomer and the branched polyolefin, so that the hot melt pressure-sensitive adhesive can still maintain good shape stability and adhesion strength at high temperatures.

[0067] Obviously, the above-described embodiments are merely examples given for clearly illustrating the embodiments of the present invention, and are not limitations on the embodiments of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the embodiments here. And these obvious changes or modifications derived from the spirit of the present invention are still within the protection scope of the present invention.

Claims

1. A high-temperature resistant hot melt pressure-sensitive adhesive, characterized in that, It includes a thermoplastic elastomer, a branched polyolefin, a modified tackifying resin and an additive; the thermoplastic elastomer includes at least one of SIS, SBS and SSBR; the branched polyolefin is prepared by reacting 1,2,4-cyclohexanetricarboxylic anhydride, a mercapto-block polymer and an epoxy polyolefin elastomer; the modified tackifying resin is prepared by reacting a p-tert-octylphenol formaldehyde resin with a polybenzene ring compound.

2. The heat-resistant hot melt pressure-sensitive adhesive according to claim 1, wherein The mercapto-block polymer is prepared by reacting a mercapto-block polymer matrix to remove thioacetate; the mercapto-block polymer matrix is prepared by reacting tert-butyl acrylate, 4-vinylbenzyl chloride and potassium thioacetate; the epoxy polyolefin elastomer is prepared by reacting a polyolefin elastomer with m-chloroperoxybenzoic acid.

3. The high-temperature resistant hot melt pressure-sensitive adhesive according to claim 1, wherein The polybenzene ring compound is prepared by reacting pyromellitic dianhydride, diethanolamine and epoxy polyisoprene.

4. The heat-resistant hot melt pressure-sensitive adhesive according to claim 1, wherein The additive includes an antioxidant and an antioxidant in a mass ratio of 1:0.4 to 0.8; the antioxidant is 2,6-di-tert-butyl-p-cresol; the antioxidant is antioxidant 1076.

5. The preparation method of a high-temperature resistant hot melt pressure-sensitive adhesive according to claim 1, characterized in that, It includes the following specific steps: S1. Under an argon atmosphere, a mercapto-block polymer matrix, N,N-dimethylformamide, n-butylamine and dithiothreitol are mixed in a mass ratio of 0.2 to 0.3:4:0.6 to 0.62:0.65, heated to 60 to 62 °C, reacted in the dark for 24 h, adjusted to pH 0.8 to 1.2 with hydrochloric acid, centrifuged and dissolved in tetrahydrofuran, rotary evaporated, then precipitated with methanol, and finally vacuum dried to obtain a mercapto-block polymer; S2. Under a nitrogen atmosphere, 1,2,4-cyclohexanetricarboxylic anhydride, a mercapto-block polymer and N,N-dimethylformamide are mixed, stirred evenly, heated to 100 to 110 °C, reacted for 3 to 5 h, an epoxy polyolefin elastomer is added, and the reaction continues for 1 to 3 h, then rotary evaporated to obtain a branched polyolefin; S3. Under a nitrogen atmosphere, diethanolamine and N,N-dimethylformamide are mixed in a mass ratio of 8 to 9:10, stirred evenly to obtain solution A; pyromellitic dianhydride and N,N-dimethylformamide are mixed in a mass ratio of 1 to 2:10, stirred evenly to obtain solution B, and solution B with a volume 3 to 4 times that of solution A is added dropwise to solution A at a rate of 1 to 3 ml / min. After reacting at room temperature for 3 to 4 h, it is washed with toluene and filtered, then epoxy polyisoprene 0.8 to 0.9 times the mass of pyromellitic dianhydride and triethylamine 0.06 to 0.08 times the mass of pyromellitic dianhydride are added, heated to 100 to 120 °C, reacted for 1 to 2 h, heated to 160 to 180 °C, reacted for 2 to 4 h, and then rotary evaporated to obtain a polybenzene ring compound; S4. p-tert-octylphenol formaldehyde resin, polybenzene ring compound, concentrated sulfuric acid and deionized water are mixed in a mass ratio of 20:0.15 to 0.18:0.4, heated to 100 to 110 °C, and formaldehyde 0.1 to 0.2 times the mass of p-tert-octylphenol formaldehyde resin is added dropwise at a rate of 1 to 3 ml / min. After reacting for 3 to 4 h, it is heated to 180 to 190 °C, reacted for 2 to 3 h, cooled to 150 to 170 °C, and vacuum dehydrated to obtain a modified tackifying resin; S5. Mix the thermoplastic elastomer, branched polyolefin, modified tackifying resin and additives, heat up to 150 - 170 °C, stir at 100 - 200 rpm for 2 - 4 h, keep warm to remove bubbles, and obtain the high-temperature resistant hot melt pressure-sensitive adhesive.

6. The preparation method of a high-temperature resistant hot melt pressure-sensitive adhesive according to claim 5, characterized in that, In the above step S1, the preparation method of the mercapto-block polymer matrix is as follows: Under a nitrogen atmosphere, mix azobisisobutyronitrile, methanol, the chain transfer agent 2-(dodecyltrithiocarbonate)-2-methylpropanoic acid and tert-butyl acrylate according to the mass ratio of 0.04 - 0.06:6:0.5 - 0.6:20 - 30, stir evenly, heat up to 62 - 66 °C, react for 12 - 16 h, add 4-vinylbenzyl chloride which is 0.32 - 0.36 times the mass of tert-butyl acrylate and tetrahydrofuran which is 0.2 - 0.6 times the mass of tert-butyl acrylate, heat up to 70 - 72 °C, react for 24 h, perform rotary evaporation at 40 - 42 °C, then precipitate with methanol for 3 - 5 times, add N-methylpyrrolidone which is 8 - 10 times the mass of tert-butyl acrylate and potassium thioacetate which is 0.14 - 0.17 times the mass of tert-butyl acrylate, stir to dissolve and react at room temperature for 24 h, then precipitate with deionized water for 3 - 5 times, and dry in vacuum at 60 - 62 °C to obtain the mercapto-block polymer matrix.

7. The preparation method of a high-temperature resistant hot melt pressure-sensitive adhesive according to claim 5, characterized in that, In the above step S2, the preparation method of the epoxy polyolefin elastomer is as follows: Mix the polyolefin elastomer, m-chloroperbenzoic acid and dichloromethane according to the mass ratio of 1:1.2 - 1.5:50, adjust the pH to 7 - 8 with sodium bicarbonate, react at room temperature for 6 - 8 h, quench with sodium thiosulfate and precipitate with methanol, filter by suction and dry to obtain the epoxy polyolefin elastomer.

8. The preparation method of a high-temperature resistant hot melt pressure-sensitive adhesive according to claim 5, characterized in that, In the above step S2, the mass ratio of 1,2,4-cyclohexanetricarboxylic anhydride, mercapto-block polymer, N,N-dimethylformamide and epoxy polyolefin elastomer is 0.6 - 1:1:3 - 5:6 - 10.

9. The preparation method of a high-temperature resistant hot melt pressure-sensitive adhesive according to claim 5, characterized in that, In the above step S3, the preparation method of the epoxy polyisoprene is as follows: Mix polyisoprene and dichloromethane according to the mass ratio of 1:20 - 30, stir evenly, then dropwise add a 3-chloroperbenzoic acid solution which is 4 - 8 times the mass of polyisoprene at a rate of 1 - 3 ml / min. The mass ratio of 3-chloroperbenzoic acid to dichloromethane in the 3-chloroperbenzoic acid solution is 1:8 - 10. After reacting for 3 - 4 h, add methanol to precipitate, filter by suction and dry in vacuum at 50 - 60 °C to obtain the epoxy polyisoprene.

10. The preparation method of a high-temperature resistant hot melt pressure-sensitive adhesive according to claim 5, characterized in that, In the above step S5, the mass ratio of the thermoplastic elastomer, branched polyolefin, modified tackifying resin and additives is 30 - 50:20 - 30:20 - 30:1 - 4.

Images