Preparation method of high-temperature-resistant alpha-methylstyrene monomer resin

Abstract

The invention relates to the technical field of chemical synthesis, in particular to a preparation method of high-temperature-resistant alpha-methylstyrene monomer resin, which comprises the following steps: drying styrene, 1, 5-cyclooctadiene, alpha-methylstyrene and vinyltoluene to obtain a mixture, adding a solvent, adding a catalyst for reaction to obtain a polymerization product, adding a catalyst for reaction to obtain the high-temperature-resistant alpha-methylstyrene monomer resin. And carrying out alkali washing, decoloration and gas stripping on the reaction product to obtain a final product. The invention provides the preparation method of the high-temperature-resistant alpha-methylstyrene monomer resin, the method is simple to operate, and the prepared monomer resin has excellent degradation resistance, can be widely applied to the fields of plastics, tires, plastics and the like, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and in particular to a method for preparing a high-temperature resistant α-methylstyrene monomer resin. Background Technology

[0002] Monomer resins have a wide range of applications, primarily including plastic products, coatings and paints, adhesives, fillers, packaging materials, and electronic materials. They improve the adhesion and weather resistance of elastic sealants, making them suitable for industries such as construction and automotive. The high molecular structure of resins gives them excellent plasticity and malleability, allowing them to be processed into various shapes and sizes through hot pressing, blow molding, and extrusion to meet diverse needs. Coatings and Paints: As a base material for coatings and paints, resins provide good adhesion, weather resistance, and chemical resistance. Resins can be mixed with pigments, solvents, and other additives to form various coatings and paints. They are widely used as tackifying resins in hot melt adhesives, pressure-sensitive adhesives (such as labels and tapes), and structural adhesives to improve initial tack and heat resistance. They are widely used in construction, furniture, electronics, and aerospace, providing a stable structure and connection for various products. Fillers: Due to their good flowability and plasticity, resins can be mixed with various fillers to form composite materials. Resin composites are lightweight, strong, and wear-resistant, and are widely used in the automotive, aerospace, and rail transportation industries. The advantages of monomeric resins mainly include increased high-temperature processing fluidity, improved plasticizing effect and crack resistance, improved injection molding effect, enhanced overmolding effect, and increased demolding speed and heat distortion temperature. Increased high-temperature processing fluidity: Monomeric resins can improve the processing fluidity of materials at high temperatures, which is particularly important for applications requiring high-temperature processing, ensuring that the material still retains good plasticity and processability at high temperatures. Increased demolding speed and heat distortion temperature: Monomeric resins can increase demolding speed and heat distortion temperature, which has a positive impact on improving production efficiency and product quality. Through their unique properties and functions, monomeric resins offer significant advantages for various applications, whether it's improving processing fluidity, plasticizing effect, or enhancing injection molding and overmolding effects, making them indispensable materials in industrial production. However, currently available monomeric resins have a critical problem in the high-temperature application range: after reaching a certain temperature, the monomeric resin itself will degrade.

[0003] Patent US 3000868 describes a method for adjusting the material ratio at low temperatures to achieve a monomer softening point of around 130°C. However, degradation occurs under conditions exceeding 180°C, leading to a decline in product performance and failure to achieve the expected results. Patent CN109535304A discloses a method for synthesizing modified α-methylstyrene oligomers, which obtains styrene / ethylidene norbornene / α-methylstyrene oligomers through cationic polymerization under the catalytic conditions of boron trifluoride diethyl ether complex.

[0004] However, none of these methods can solve the problem of monomer resins being easily degraded at high temperatures. Summary of the Invention

[0005] To address the shortcomings of the aforementioned technologies, this invention provides a method for preparing high-temperature resistant α-methylstyrene monomer resin, which effectively solves the problem of its high-temperature degradation.

[0006] This invention discloses a method for preparing a high-temperature resistant α-methylstyrene monomer resin, comprising the following steps:

[0007] Step 1: Mix 75-115 parts by mass of styrene derivatives and their polymers and 0.5-2 parts by mass of cyclodienes and dry them. The moisture content is measured to be less than 200 ppm, and this mixture is recorded as mixture A. The styrene derivatives and their polymers contain at least 3 substances, one of which is α-methylstyrene, and the content of α-methylstyrene is 40-53 parts by mass.

[0008] Step 2: Take 25-40 parts by weight of mixture A and 60-75 parts by weight of solvent and add them to the reaction vessel, and stir at a uniform speed;

[0009] Step 3: Take 0.5 parts by mass of Lewis acid catalyst and add it to a constant pressure funnel. Add it dropwise to the reactor for 0.3-0.6 hours at a temperature of -10 to 0°C. The reaction time is 1-2 hours at a temperature of -5 to 0°C to obtain polymerization solution B.

[0010] Step 4: Add 30% alkali solution to the above polymerization solution B at a mass ratio of 1:1, stir at room temperature, and let stand to separate into layers to obtain polymerization solution C.

[0011] Step 5: The polymerization liquid C is stripped by air to remove unreacted raw materials and solvents, finally obtaining high-temperature resistant α-methylstyrene monomer resin.

[0012] Styrene derivatives and their polymers other than α-methylstyrene include two or more of the following: styrene, methylstyrene, p-tert-butylstyrene, vinyltoluene, and polystyrene.

[0013] Preferably, styrene derivatives and their polymers other than α-methylstyrene are: styrene and vinyltoluene, wherein the content of styrene is 30-50 parts by mass and the content of vinyltoluene is 5-12 parts by mass.

[0014] The cyclodiene includes one or more of the following: cyclooctadiene, 1,5-cyclooctadiene, 3-methyl-1,5-cyclooctadiene, and 1,7-cyclohexadiene.

[0015] Preferably, the cyclodiene is 1,5-cyclooctadiene.

[0016] The drying agent used in step 1 is one or more of the following: anhydrous sodium sulfate, activated carbon, silica gel, and molecular sieve.

[0017] Preferably, the desiccant is a 3A grade molecular sieve.

[0018] The solvent in step 2 is one or more of the following: mineral oil, carbon tetrachloride, n-hexane, n-heptane, toluene, xylene, and acetone.

[0019] Toluene is preferred as the solvent.

[0020] The Lewis acid catalyst in step 3 is one or more of the following: trifluoromethanesulfonate, trimethylaluminum, triphenylboron, ytterbium trifluoromethanesulfonate, aluminum trichloride, dichlorodicyclopentadiene, zinc chloride, boron trifluoride ether, and trichloromethanesulfonic acid.

[0021] As a preferred option, the Lewis acid catalyst is boron trifluoride diethyl ether.

[0022] The alkaline solution in step 4 is one or more of the following: potassium hydroxide ethanol solution, sodium hydroxide aqueous solution, potassium hydroxide, and sodium bicarbonate.

[0023] Preferably, the alkaline solution is an aqueous solution of sodium hydroxide.

[0024] This invention addresses the problem of high-temperature degradation of existing high-softening-point α-methylstyrene monomer resins by introducing cyclic non-conjugated dienes to alter the molecular spatial structure of α-methylstyrene monomer resins. The aliphatic ring structure of 1,5-cyclooctadiene is more resistant to high-temperature oxidation than benzene rings, which may delay the thermal decomposition of the resin. The steric hindrance effect of the cyclic structure reduces the regularity of the molecular arrangement, thereby decreasing the resin viscosity.

[0025] The present invention provides a method for preparing a high-temperature resistant α-methylstyrene monomer resin, which solves the problem that existing high-softening-point α-methylstyrene monomer resins are easily degraded at high temperatures, and effectively broadens the application range of mono-α-methylstyrene monomer resins.

[0026] The method for preparing a high-temperature resistant α-methylstyrene monomer resin obtained by the present invention does not require complex and expensive large-scale process equipment, the preparation steps are relatively simple, the raw materials are widely available, the cost is low, and the product is a high-temperature resistant α-methylstyrene monomer resin that can be industrialized and mass-produced, generating considerable economic benefits. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0028] Example 1:

[0029] This invention discloses a method for preparing a high-temperature resistant α-methylstyrene monomer resin. The resin is prepared by mixing styrene, 1,5-cyclooctadiene, α-methylstyrene, and vinyltoluene in a mass ratio of 38:2:48:12, adding a molecular sieve, and drying for 24 hours. The final moisture content is measured to be less than 350 ppm, which is designated as mixture A. Mixture A is then... 29.5 parts by mass and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and added dropwise to the reactor over a period of 0.45 h at a temperature of -10 to -7 °C. The reaction time was 1.5 h at a temperature of -5 °C to obtain polymerization solution B. A 30% sodium hydroxide aqueous solution was added at a 1:1 ratio, and the stirring speed was adjusted to 150 rpm. The mixture was stirred at room temperature for 5 min and allowed to stand to separate into layers to obtain polymerization solution C. Polymerization solution C was stripped under negative pressure at 260 °C to remove unreacted raw materials and solvents, finally yielding high-temperature resistant α-methylstyrene monomer resin.

[0030] Example 2:

[0031] This invention discloses a method for preparing a high-temperature resistant α-methylstyrene monomer resin. The resin is prepared by mixing styrene, 1,5-cyclooctadiene, α-methylstyrene, and vinyltoluene in a mass ratio of 40:2:46:12, adding a molecular sieve, and drying for 24 hours. The final moisture content is measured to be less than 350 ppm, which is designated as mixture A. Mixture A is then... 29.5 parts by mass and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and added dropwise to the reactor over a period of 0.45 h at a temperature of -10 to -7 °C. The reaction time was 1.5 h at a temperature of -5 °C to obtain polymerization solution B. A 30% sodium hydroxide aqueous solution was added at a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 min at room temperature. After standing and separating into layers, polymerization solution C was obtained. Unreacted raw materials and solvents were removed by gas stripping at 260 °C under negative pressure to finally obtain high-temperature resistant α-methylstyrene monomer resin.

[0032] Example 3:

[0033] This invention discloses a method for preparing a high-temperature resistant α-methylstyrene monomer resin. The resin is prepared by mixing styrene, 1,5-cyclooctadiene, α-methylstyrene, and vinyltoluene in a mass ratio of 40:2:48:10, adding a molecular sieve, and drying for 24 hours. The final moisture content is less than 350 ppm, which is designated as mixture A. Mixture A is then... 29.5 parts by mass and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and added dropwise to the reactor over a period of 0.45 h at a temperature of -10 to -7 °C. The reaction time was 1.5 h at a temperature of -5 °C to obtain polymerization solution B. A 30% sodium hydroxide aqueous solution was added at a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 min at room temperature. After standing and separating into layers, polymerization solution C was obtained. Unreacted raw materials and solvents were removed by gas stripping at 260 °C under negative pressure to finally obtain high-temperature resistant α-methylstyrene monomer resin.

[0034] Example 4:

[0035] This invention discloses a method for preparing high-temperature resistant α-methylstyrene monomer resin. The mixture is prepared by mixing styrene, cyclooctadiene, α-methylstyrene, and vinyltoluene in a mass ratio of 38:2:48:12, adding a molecular sieve, and drying for 24 hours until the final moisture content is less than 350 ppm (mixture A). 29.5 parts by mass of mixture A and 70 parts by mass of toluene are added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst are added to a constant pressure funnel, diluted with toluene, and dripped into a reaction vessel over 0.45 hours at a temperature of -10 to -7°C. The reaction time is 1.5 hours at a temperature of -5°C, yielding polymerization solution B. A 30% sodium hydroxide aqueous solution is added in a 1:1 ratio, and the mixture is stirred at 150 rpm for 5 minutes at room temperature. After standing and separating, polymerization solution C is obtained. Polymerization solution C is then subjected to gas stripping at 260°C under negative pressure to remove unreacted raw materials and solvents, ultimately yielding the high-temperature resistant α-methylstyrene monomer resin.

[0036] Example 5:

[0037] This invention discloses a method for preparing a high-temperature resistant α-methylstyrene monomer resin. The resin is prepared by mixing styrene, 3-methyl-1,5-cyclooctadiene, α-methylstyrene, and vinyltoluene in a mass ratio of 38:2:48:12, adding a molecular sieve, and drying for 24 hours. The final moisture content is measured to be less than 350 ppm, which is designated as mixture A. Mixture A is then... 29.5 parts by mass and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and added dropwise to the reactor over a period of 0.45 h at a temperature of -10 to -7 °C. The reaction time was 1.5 h at a temperature of -5 °C to obtain polymerization solution B. A 30% sodium hydroxide aqueous solution was added at a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 min at room temperature. After standing and separating into layers, polymerization solution C was obtained. Unreacted raw materials and solvents were removed by gas stripping at 260 °C under negative pressure to finally obtain high-temperature resistant α-methylstyrene monomer resin.

[0038] Example 5:

[0039] This invention discloses a method for preparing a high-temperature resistant α-methylstyrene monomer resin. The resin is prepared by mixing styrene, 3-methyl-1,5-cyclooctadiene, α-methylstyrene, and vinyltoluene in a mass ratio of 38:2:48:12, adding a molecular sieve, and drying for 24 hours. The final moisture content is measured to be less than 350 ppm, which is designated as mixture A. Mixture A is then... 29.5 parts by mass and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and added dropwise to the reactor over a period of 0.45 h at a temperature of -10 to -7 °C. The reaction time was 1.5 h at a temperature of -5 °C to obtain polymerization solution B. A 30% sodium hydroxide aqueous solution was added at a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 min at room temperature. After standing and separating into layers, polymerization solution C was obtained. Unreacted raw materials and solvents were removed by gas stripping at 260 °C under negative pressure to finally obtain high-temperature resistant α-methylstyrene monomer resin.

[0040] Example 6:

[0041] This invention discloses a method for preparing a high-temperature resistant α-methylstyrene monomer resin. The resin is prepared by mixing styrene, 1,7-cyclohexadiene, α-methylstyrene, and vinyltoluene in a mass ratio of 38:2:48:12, adding a molecular sieve, and drying for 24 hours. The final moisture content is measured to be less than 350 ppm, which is designated as mixture A. Mixture A is then... 29.5 parts by mass and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and added dropwise to the reactor over a period of 0.45 h at a temperature of -10 to -7 °C. The reaction time was 1.5 h at a temperature of -5 °C to obtain polymerization solution B. A 30% sodium hydroxide aqueous solution was added at a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 min at room temperature. After standing and separating into layers, polymerization solution C was obtained. Unreacted raw materials and solvents were removed by gas stripping at 260 °C under negative pressure to finally obtain high-temperature resistant α-methylstyrene monomer resin.

[0042] Comparative Example 1:

[0043] This comparative example discloses a method for preparing α-methylstyrene monomer resin. A mixture of styrene, toluene, α-methylstyrene, and vinyltoluene by mass ratio of 38:2:48:12 was added to a molecular sieve and dried for 24 hours. The final moisture content was measured to be less than 200 ppm, which was designated as mixture A. 29.5 parts by mass of mixture A and 70 parts by mass of toluene were added to a three-necked flask and stirred at 350 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and uniformly added dropwise to a reaction vessel over 0.45 hours at a temperature of -10 to -7°C. The reaction time was 1.5 hours at a temperature of -5°C, yielding polymerization solution B. A 30% sodium hydroxide aqueous solution was added in a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 minutes at room temperature. After standing and separating, polymerization solution C was obtained. Polymerization solution C was subjected to gas stripping at 260°C under negative pressure to remove unreacted raw materials and solvents, ultimately yielding α-methylstyrene monomer resin.

[0044] Comparative Example 2:

[0045] This comparative example discloses a method for preparing α-methylstyrene monomer resin. A mixture of styrene, toluene, α-methylstyrene, and vinyltoluene by mass ratio of 40:2:46:12 was added to a molecular sieve and dried for 24 hours. The final moisture content was measured to be less than 200 ppm, which was identified as mixture A. 29.5 parts by mass of mixture A and 70 parts by mass of toluene were added to a three-necked flask and stirred at 350 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and uniformly added dropwise to a reaction vessel over 0.45 hours at a temperature of -10 to -7°C. The reaction time was 1.5 hours at a temperature of -5°C, yielding polymerization liquid B. A 30% sodium hydroxide aqueous solution was added in a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 minutes at room temperature. After standing and separating, polymerization liquid C was obtained. Polymerization liquid C was then subjected to gas stripping at 260°C under negative pressure to remove unreacted raw materials and solvents, ultimately yielding α-methylstyrene monomer resin.

[0046] Comparative Example 3:

[0047] This comparative example discloses a method for preparing α-methylstyrene monomer resin. A mixture of styrene, toluene, α-methylstyrene, and vinyltoluene by mass ratio of 40:2:48:10 was added to a molecular sieve and dried for 24 hours. The final moisture content was measured to be less than 200 ppm, which was designated as mixture A. 29.5 parts by mass of mixture A and 70 parts by mass of toluene were added to a three-necked flask and stirred at 350 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and uniformly added dropwise to a reaction vessel over 0.45 hours at a temperature of -10 to -7°C. The reaction time was 1.5 hours at a temperature of -5°C, yielding polymerization liquid B. A 30% sodium hydroxide aqueous solution was added in a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 minutes at room temperature. After standing and separating, polymerization liquid C was obtained. Polymerization liquid C was then subjected to gas stripping at 260°C under negative pressure to remove unreacted raw materials and solvents, ultimately yielding α-methylstyrene monomer resin.

[0048] Comparative Example 4:

[0049] This comparative example discloses a method for preparing α-methylstyrene monomer resin. A mixture of styrene, α-methylstyrene, and vinyltoluene in a ratio of 45:43:12 was added to a molecular sieve and dried for 24 hours, resulting in a final moisture content of less than 200 ppm, designated as mixture A. 29.5 parts by mass of mixture A and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and uniformly added dropwise to a reaction vessel over 0.45 hours at a temperature of -10 to -7°C. The reaction time was 1.5 hours at a temperature of -5°C, yielding polymerization solution B. A 30% sodium hydroxide aqueous solution was added in a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 minutes at room temperature. After standing and separating into layers, polymerization solution C was obtained. Polymerization solution C was subjected to gas stripping at 260°C under negative pressure to remove unreacted raw materials and solvents, ultimately yielding α-methylstyrene monomer resin.

[0050] Comparative Example 5:

[0051] This comparative example discloses a method for preparing α-methylstyrene monomer resin. A mixture of styrene, α-methylstyrene, and vinyltoluene in a ratio of 40:48:12 was added to a molecular sieve and dried for 24 hours, resulting in a final moisture content of less than 200 ppm, designated as mixture A. 29.5 parts by mass of mixture A and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and uniformly added dropwise to a reaction vessel over 0.45 hours at a temperature of -10 to -7°C. The reaction time was 1.5 hours at a temperature of -5°C, yielding polymerization solution B. A 30% sodium hydroxide aqueous solution was added in a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 minutes at room temperature. After standing and separating into layers, polymerization solution C was obtained. Polymerization solution C was subjected to gas stripping at 260°C under negative pressure to remove unreacted raw materials and solvents, ultimately yielding α-methylstyrene monomer resin.

[0052] Comparative Example 6:

[0053] This comparative example discloses a method for preparing α-methylstyrene monomer resin. A mixture of styrene, α-methylstyrene, and vinyltoluene in a ratio of 38:50:12 was added to a molecular sieve and dried for 24 hours, resulting in a final moisture content of less than 200 ppm, designated as mixture A. 29.5 parts by mass of mixture A and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and uniformly added dropwise to a reaction vessel over 0.45 hours at a temperature of -10 to -7°C. The reaction time was 1.5 hours at a temperature of -5°C, yielding polymerization solution B. A 30% sodium hydroxide aqueous solution was added in a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 minutes at room temperature. After standing and separating into layers, polymerization solution C was obtained. Polymerization solution C was subjected to gas stripping at 260°C under negative pressure to remove unreacted raw materials and solvents, ultimately yielding α-methylstyrene monomer resin.

[0054] Comparative Example 7:

[0055] This comparative example discloses a method for preparing α-methylstyrene monomer resin. A mixture of styrene, α-methylstyrene, and vinyltoluene in a ratio of 45:48:7 was added to a molecular sieve and dried for 24 hours, resulting in a final moisture content of less than 200 ppm, designated as mixture A. 29.5 parts by mass of mixture A and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and uniformly added dropwise to a reaction vessel over 0.45 hours at a temperature of -10 to -7°C. The reaction time was 1.5 hours at a temperature of -5°C, yielding polymerization solution B. A 30% sodium hydroxide aqueous solution was added in a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 minutes at room temperature. After standing and separating into layers, polymerization solution C was obtained. Polymerization solution C was subjected to gas stripping at 260°C under negative pressure to remove unreacted raw materials and solvents, ultimately yielding α-methylstyrene monomer resin.

[0056] Comparative Example 8:

[0057] This comparative example discloses a method for preparing α-methylstyrene monomer resin. A mixture of styrene, α-methylstyrene, and vinyltoluene in a ratio of 40:53:7 was added to a molecular sieve and dried for 24 hours, resulting in a final moisture content of less than 200 ppm, designated as mixture A. 29.5 parts by mass of mixture A and 70 parts by mass of toluene were added to a three-necked flask and stirred at 300 rpm. 0.5 parts by mass of boron trifluoride diethyl ether catalyst were added to a constant pressure funnel, diluted with toluene, and uniformly added dropwise to a reaction vessel over 0.45 hours at a temperature of -10 to -7°C. The reaction time was 1.5 hours at a temperature of -5°C, yielding polymerization solution B. A 30% sodium hydroxide aqueous solution was added in a 1:1 ratio, and the mixture was stirred at 150 rpm for 5 minutes at room temperature. After standing and separating into layers, polymerization solution C was obtained. Polymerization solution C was subjected to gas stripping at 260°C under negative pressure to remove unreacted raw materials and solvents, ultimately yielding α-methylstyrene monomer resin.

[0058] Table 1. Raw material suppliers and specifications for the examples and comparative examples.

[0059] raw material Purchase manufacturer Model Specifications styrene Tianjin Fuchen Chemical Reagent Factory Analytical Pure α-Methylstyrene Shanghai Aladdin Biochemical Technology Co., Ltd. Analytical Pure Vinyltoluene Wuhan Maikairui Chemical Co., Ltd. Analytical Pure Boron trifluoride diethyl ether Jinan Huifengda Chemical Co., Ltd. Analytical Pure 1,5-Cyclooctadiene Hubei Chengfeng Chemical Co., Ltd. Analytical Pure Molecular sieve Suzhou Aoxin Molecular Sieve Co., Ltd. 3A Sodium hydroxide Shenzhen Chimelong Technology Co., Ltd. Industrial grade Toluene Jinan Shanhai Chemical Technology Co., Ltd. Industrial grade

[0060] Table 2a-Methylstyrene monomer resin viscosity test summary table

[0061]

[0062]

[0063] Table 3 Evaluation of the softening point and degradation performance of α-methylstyrene monomer resin

[0064]

[0065]

[0066] Table 4 Evaluation of the molecular weight degradation performance of α-methylstyrene monomer resin

[0067]

[0068]

[0069] As shown in Table 2, the resin melt viscosity of Examples 1, 2, and 3 is lower than that of Comparative Examples 1, 2, 3, 4, 5, 6, 7, and 8. Therefore, the addition of 1,5-cyclooctadiene can effectively reduce the resin melt viscosity.

[0070] Compared with Examples 1, 4, 5, and 6, the 1,5-cyclooctadiene monomer among the non-conjugated dienes is the best and has stronger resistance to thermal degradation.

[0071] As can be seen from Tables 3 and 4 above, the conditions in Example 1 are optimal. The slowest decrease in softening point and the least decrease in molecular weight are achieved by high-temperature degradation at 180℃, 200℃, and 250℃ for 8 hours.

[0072] Therefore, the high-temperature resistant α-methylstyrene monomer resin prepared according to the method in Example 1 can effectively slow down the thermal degradation time of the resin, and the effect is optimal. The method of preparing synthetic resin is simple and the raw materials are readily available. The prepared α-methylstyrene monomer resin can broaden the application market of monomer resin.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simplification, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a high-temperature resistant α-methylstyrene monomer resin, characterized in that: Includes the following steps: Step 1: Mix 75-115 parts by mass of styrene derivatives and their polymers and 0.5-2 parts by mass of cyclodienes and dry them. The moisture content is measured to be less than 200 ppm, and this mixture is recorded as mixture A. The styrene derivatives and their polymers contain at least 3 substances, one of which is α-methylstyrene, and the content of α-methylstyrene is 40-53 parts by mass. Step 2: Take 25-40 parts by weight of mixture A and 60-75 parts by weight of solvent and add them to the reaction vessel, and stir at a uniform speed; Step 3: Take 0.5 parts by mass of Lewis acid catalyst and add it to a constant pressure funnel. Add it dropwise to the reactor for 0.3-0.6 hours at a temperature of -10 to 0°C. The reaction time is 1-2 hours at a temperature of -5 to 0°C to obtain polymerization solution B. Step 4: Add 30% alkali solution to the above polymerization solution B at a mass ratio of 1:1, stir at room temperature, and let stand to separate into layers to obtain polymerization solution C. Step 5: The polymerization liquid C is stripped by air to remove unreacted raw materials and solvents, finally obtaining high-temperature resistant α-methylstyrene monomer resin.

2. The method for preparing a high-temperature resistant α-methylstyrene monomer resin according to claim 1, characterized in that: Styrene derivatives and their polymers other than α-methylstyrene include two or more of the following: styrene, methylstyrene, p-tert-butylstyrene, vinyltoluene, and polystyrene.

3. The method for preparing a high-temperature resistant α-methylstyrene monomer resin according to claim 2, characterized in that: Styrene derivatives and their polymers other than α-methylstyrene include: styrene and vinyltoluene, with styrene content of 30-50 parts by mass and vinyltoluene content of 5-12 parts by mass.

4. The method for preparing a high-temperature resistant α-methylstyrene monomer resin according to claim 1, characterized in that: The cyclodiene includes one or more of the following: cyclooctadiene, 1,5-cyclooctadiene, 3-methyl-1,5-cyclooctadiene, and 1,7-cyclohexadiene.

5. The method for preparing a high-temperature resistant α-methylstyrene monomer resin according to claim 1, characterized in that: The drying agent used in step 1 is one or more of the following: anhydrous sodium sulfate, activated carbon, silica gel, and molecular sieve.

6. The method for preparing a high-temperature resistant α-methylstyrene monomer resin according to claim 1, characterized in that: The solvent in step 2 is one or more of the following: mineral oil, carbon tetrachloride, n-hexane, n-heptane, toluene, xylene, and acetone.

7. The method for preparing a high-temperature resistant α-methylstyrene monomer resin according to claim 1, characterized in that: The Lewis acid catalyst in step 3 is one or more of the following: trifluoromethanesulfonate, trimethylaluminum, triphenylboron, ytterbium trifluoromethanesulfonate, aluminum trichloride, dichlorodicyclopentadiene, zinc chloride, boron trifluoride ether, and trichloromethanesulfonic acid.

8. The method for preparing a high-temperature resistant α-methylstyrene monomer resin according to claim 1, characterized in that: The alkaline solution in step 4 is one or more of the following: potassium hydroxide ethanol solution, sodium hydroxide aqueous solution, potassium hydroxide, and sodium bicarbonate.

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