Preparation method of polystyrene with high heat resistance and high impact strength

Abstract

The invention provides a preparation method of polystyrene with high heat resistance and high impact strength, and belongs to the technical field of polymer materials. In the production process of polystyrene, part of methanol is added into toluene or ethylbenzene as a reaction solvent; the addition of methanol is beneficial to removal of reaction heat in a polymerization system, and meanwhile, the viscosity of the reaction system can be lower. The combination of the two makes the prepared high impact strength polystyrene have narrow molecular weight distribution, high heat resistance and high impact strength.

Description

Technical Field

[0001] The present application belongs to the technical field of polymer materials, and specifically relates to a method for preparing polystyrene with high heat resistance and high impact strength. Background Art

[0002] Common high-impact polystyrene is modified by adding a certain amount of rubber during the production process, which improves its impact strength and expands its application range. However, compared with ordinary polystyrene, the addition of rubber often significantly reduces its heat resistance, which to some extent limits its application. Furthermore, the addition of rubber during the reaction of common high-impact polystyrene results in excessive overall viscosity, which impairs mixing and further expands its molecular weight distribution. This broadens the molecular weight distribution of the polymer and reduces its impact strength to a certain extent.

[0003] To reduce the viscosity of the polymer reaction system, a certain amount of solvent is usually added. However, as the polymerization reaction conversion rate increases, the polymerization reaction system will experience the so-called "gel effect," which automatically accelerates the reaction. This makes it difficult to remove the polymerization heat from the polymerization reaction system, which can easily lead to local overheating of the reaction system. This ultimately results in a wider molecular weight distribution of the target polymer product, lower impact strength, and decreased heat resistance. The polymerization reaction solvents commonly used in polystyrene production are mostly aromatic hydrocarbon solvents, such as toluene and ethylbenzene. These solvents have high boiling points and are generally not very effective in removing the reaction heat.

[0004] Therefore, it is necessary to develop a method for preparing polystyrene with high heat resistance and high impact strength, reduce the molecular weight distribution range of the obtained polystyrene, and improve its heat resistance while maintaining high impact strength to meet application requirements. Summary of the Invention

[0005] The purpose of this application is to provide a method for preparing high-heat-resistant and high-impact strength polystyrene.

[0006] To achieve the above objectives, this application adopts the following technical solutions: A method for preparing high-heat-resistant and high-impact-strength polystyrene comprises the following steps: The reaction liquid consisting of vinyl aromatic monomer, polybutadiene rubber, solvent and additive is continuously transported to a multi-stage series reactor group; After the reaction is completed, the reaction liquid output from the last reactor in the multi-stage series reactor group is transferred to a devolatilizer for devolatilization to obtain high heat-resistant and high impact strength polystyrene.

[0007] Beneficial technical effects: In the polystyrene production process, methanol is added to toluene or ethylbenzene as a reaction solvent. The advantages of adding methanol are as follows: 1. Methanol has a low boiling point, which makes it easier to evaporate and reflux in the polymerization system. The heat generated by the polymerization is easier to remove, and the local overheating caused by high viscosity during the polymerization process can be reduced.

[0008] 2. Above 120°C, the mixed solvent of methanol and aromatic hydrocarbons has better solubility for the polymer, the viscosity of the reaction system is lower, and the effect of the mixed reaction is better.

[0009] Based on the above effects, by adding some methanol to toluene or ethylbenzene as a reaction solvent during the polystyrene production process, the temperature of the polymerization reaction process is made more uniform and the viscosity of the reaction system is lower, so that the molecular weight distribution of the polymer target product is narrower, while maintaining high impact strength and having higher heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Implemented flow chart for high heat and high impact polystyrene production.

[0011] Meaning of the reference numerals: R1, primary reactor; R2, secondary reactor; R3, tertiary reactor. DETAILED DESCRIPTION

[0012] In order to make the technical problems, technical solutions, and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below with reference to the following examples. However, this should not be construed as limiting the scope of this application to the following examples. Without departing from the above-mentioned method concepts of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0013] The terms used in this application are for the purpose of describing particular embodiments only and are not intended to be limiting of this application.

[0014] As used in this application, the singular forms "for," "or," "an," "any," "any one," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0015] This application adopts the following technical solutions: A method for preparing high-heat-resistant and high-impact-strength polystyrene comprises the following steps: The reaction liquid consisting of vinyl aromatic monomer, polybutadiene rubber, solvent and additives is continuously transported to a multi-stage series reactor group; the solvent is a mixture of ethylbenzene and methanol or toluene and methanol in any proportion; After the reaction is completed, the reaction liquid output from the last reactor in the multi-stage series reactor group is transferred to a devolatilizer for devolatilization to obtain high heat-resistant and high impact strength polystyrene.

[0016] Preferably, the auxiliary agent includes an initiator, a plasticizer, an antioxidant and a lubricant; the mass ratio of the vinyl aromatic monomer, the solvent, the polybutadiene rubber, the antioxidant, the plasticizer, the initiator and the lubricant is 100: (3~10): (6~7): (0.5~2): (1~2): (0.01~0.02): (0.05~0.2).

[0017] Preferably, in the method for preparing the high-heat-resistant and high-impact-strength polystyrene, the devolatilization time is 1 hour.

[0018] Preferably, the reaction temperature in each stage of the multi-stage series reactor group is the same or different.

[0019] Preferably, if the reaction temperature in each stage of the multi-stage series reactor group is different, there are at least two stages of reactors in the multi-stage series reactor group, and the reaction temperature in the relatively later stage reactor of the two stages is greater than the reaction temperature in the relatively earlier stage reactor.

[0020] Preferably, the two-stage reactors are adjacent or non-adjacent.

[0021] Preferably, if the two-stage reactors are adjacent to each other, the reaction temperature in the adjacent subsequent reactor is higher than the reaction temperature in the adjacent preceding reactor.

[0022] Preferably, if the two-stage reactors are not adjacent, then in the two non-adjacent reactors, the reaction temperature in the relatively later-stage reactor is higher than the reaction temperature in the relatively earlier-stage reactor.

[0023] Preferably, each stage reactor of the multi-stage series reactor group is independently any one of a plug flow reactor and a stirred tank reactor.

[0024] Preferably, in the embodiment of the present application, the multi-stage series reactor group includes a primary reactor, a secondary reactor and a tertiary reactor; the reaction temperature in the primary reactor is 115-130°C; the reaction temperature in the secondary reactor is 135-145°C; and the reaction temperature in the tertiary reactor is 145-155°C.

[0025] Preferably, for any two adjacent reactors in the multi-stage series reactor group, the condition for transferring the reaction liquid from the adjacent previous reactor to the adjacent next reactor or devolatilizer is that the reaction liquid in the adjacent previous reactor is within the corresponding set conversion rate threshold range.

[0026] Preferably, if the reaction temperature in each reactor of the multi-stage series reactor group is the same, the reaction liquid in the adjacent previous reactor must be within the corresponding set conversion rate threshold range before the reaction liquid is transported from the adjacent previous reactor to the adjacent subsequent reactor or devolatilizer.

[0027] The above control operations enable each reactor to function in its most suitable reaction stage, preventing the reactants from entering the subsequent stage too early or too late; and can match the material handling capacity of each level of reactor with the reaction capacity, so that the catalyst, reaction medium and other resources in the reactor can be fully utilized, reducing resource waste, thereby improving the efficiency of the entire reaction system.

[0028] In addition, the above-mentioned control operation avoids unreacted raw materials or intermediate products that may be carried into subsequent stages due to incomplete reaction, and also helps to more fully convert the reactants into the target products, reduce the occurrence of side reactions, and thus improve the purity and quality stability of the target products.

[0029] Preferably, in the embodiment of the present application, the multi-stage series reactor group includes a primary reactor, a secondary reactor and a tertiary reactor; the set conversion rate threshold range of polystyrene in the primary reactor is 25-35%; the set conversion rate threshold range of polystyrene in the secondary reactor is 55-65%; the set conversion rate threshold range of polystyrene in the tertiary reactor is 70-80%.

[0030] Preferably, the vinyl aromatic monomer includes at least one of styrene and α-methylstyrene.

[0031] Preferably, the polybutadiene rubber includes at least one of low-cis polybutadiene rubber and high-cis polybutadiene rubber.

[0032] Preferably, examples of the initiator include (but are not limited to): 1. Azo compounds: such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2-methylvaleronitrile), etc.; 2. Peroxydiacyl compounds: such as dilauroyl peroxide, eicosanoyl peroxide or dibenzoyl peroxide, etc.; 3. Peroxydioxane compounds: such as 2,5-dimethyl-2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropyl peroxide or 1,3-bis(tert-butylperoxyisopropyl)benzene, etc.; 4. Peroxyester compounds: such as tert-butyl peroxypivalate or 2,,5-dimethyl-2,5-di(2-ethylhexanol peroxy)hexane, etc.; 5. Peroxycarbonate compounds: such as 2-ethylhexyl tert-amyl peroxycarbonate, 2-ethylhexyl tert-butyl peroxycarbonate, etc.; 6. Peroxydicarbonate compounds: such as dimyristyl peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, etc.; 7. Peroxyketal compounds: 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,2-bis(4,4-di(tert-butylperoxy)cyclohexyl)propane, etc.; 8. Hydroperoxide compounds: tert-butyl hydroperoxide, isopropyl hydroperoxide, etc.

[0033] Preferably, the plasticizer includes mineral oil, more preferably mineral oil with a viscosity of 60-80 mPa·s at 25° C. The plasticizer can well adjust the melt flow rate of the target product to meet application requirements.

[0034] Preferably, examples of the antioxidant include (but are not limited to): octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (abbreviated as Antioxidant 1076), trisnonylphenyl phosphite (abbreviated as TNPP), 2,6-di-tert-butyl-4-methylphenol, thio-diethylene-bis(3,5-di-tert-butyl-4-hydroxy-phenylpropionate), tetrakis[methylene(3,5-di-tert-butyl-4-hydroxy-phenylpropionate)]methane, 1,1-bis(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, etc. The addition of antioxidants helps prevent excessive crosslinking and aging of the rubber, which affects the impact strength of the final target product.

[0035] Preferably, examples of the lubricant include (but are not limited to): metal soaps such as zinc stearate, magnesium stearate, calcium stearate, ethylene bisstearamide (abbreviated as EBS), methylene bisstearamide, palmitamide, butyl stearate, stearic acid palmitate, polyethylene wax, etc.

[0036] Preferably, the molecular weight distribution range of the high heat-resistant and high impact strength polystyrene is 1.5-2.0.

[0037] Preferably, the Vicat softening point of the high heat-resistant and high impact strength polystyrene is not lower than 90°C.

[0038] The following will be attached Figure 1 Taking this as an example, and combining different embodiments, the preparation method of high heat-resistant and high impact strength polystyrene provided by the present application is specifically described.

[0039] The dissolved rubber solution (including additives) is transported to the first-stage reactor for pre-polymerization. After reaching the predetermined conversion rate, the reactants are transported to the second-stage reactor for reaction. After reaching the predetermined conversion rate again, the reactants are transported to the third-stage reactor for reaction. After the reaction is completed, devolatilization is carried out to produce high-heat-resistant and high-impact strength polystyrene.

[0040] Raw materials used in the experiment: Styrene: purity 99.8%, moisture content below 500 ppm, produced by Jiangsu Xinyang Technology Group, remove the inhibitor before use.

[0041] Ethylbenzene: purity 99.9%, moisture content below 500 ppm, Jiangsu Xinyang Technology Group; Rubber: 255P, low cis, 1,2 structure content 8%, Liaoning North Dainasso Co., Ltd. 55AE, low cis, 1,2 structure content 10%, Shanghai Gaoqiao Petrochemical Co., Ltd.; Methanol: analytical grade, Sinopharm Chemical Co., Ltd.; Initiator: tert-butyl peroxyisopropyl carbonate, Nouryon; Plasticizer: White oil No. 68, Zhejiang Zhengxin Petroleum Technology Co., Ltd. Antioxidant: Antioxidant 1076, Yixing Angel Synthetic Chemical Company; Lubricant: zinc stearate, Guangzhou Yuanda New Materials Co., Ltd.

[0042] The following will describe in detail a method for preparing high heat-resistant and high impact strength polystyrene provided by the present application in combination with different examples.

[0043] Example 1

[0044] A method for preparing high-heat-resistant and high-impact-strength polystyrene comprises the following steps: 1. Mix styrene monomer, solvent, rubber 255P, antioxidant 1076 and white oil. After the rubber is completely dissolved, add tert-butyl peroxyisopropyl carbonate and zinc stearate to the rubber solution to obtain a mixed solution. Figure 1 In the middle flow chart, the reaction liquid is passed into the primary reactor R1 for prepolymerization at a temperature of 120°C. After the conversion rate reaches 30%, the reaction liquid is passed into the secondary reactor R2; Among them, the mass ratio of styrene monomer, solvent (ethylbenzene: methanol = 4:1), rubber 255P, antioxidant 1076, white oil, tert-butyl peroxyisopropyl carbonate and zinc stearate is 100:5:6:0.1:1:0.01:0.1.

[0045] 2. The reaction temperature in the secondary reactor R2 is 140°C. After the reaction is carried out until the conversion rate of the reaction liquid reaches 60%, the reaction liquid is passed into the tertiary reactor R3; 3. The reaction temperature in the tertiary reactor R3 is 152°C. After the reaction is carried out until the conversion rate of the reaction liquid reaches 75%, the reaction liquid is transferred to the devolatilizer for devolatilization. The devolatilization is continuously operated for 1 hour, and then samples are taken to test various indicators of the obtained high-heat-resistant and high-impact strength polystyrene.

[0046] Example 2

[0047] A method for preparing high-heat-resistant and high-impact-strength polystyrene comprises the following steps: 1. Mix styrene monomer, ethylbenzene, methanol, rubber 255P, antioxidant 1076 and white oil. After the rubber is completely dissolved, add tert-butyl peroxyisopropyl carbonate and zinc stearate to the rubber solution to obtain a mixed solution. Figure 1 In the middle flow chart, the reaction liquid is passed into the primary reactor R1 for prepolymerization at a temperature of 120°C. After the conversion rate reaches 30%, the reaction liquid is passed into the secondary reactor R2; Among them, the mass ratio of styrene monomer, solvent (ethylbenzene: methanol = 1:4), rubber 255P, antioxidant 1076, white oil, tert-butyl peroxyisopropyl carbonate and zinc stearate is 100:5:6:0.1:1:0.01:0.1.

[0048] 2. The reaction temperature in the secondary reactor R2 is 140°C. After the reaction reaches a conversion rate of 60%, the reaction liquid is passed into the tertiary reactor R3; 3. The reaction temperature in the tertiary reactor R3 is 152°C. After the reaction is carried out until the conversion rate of the reaction liquid reaches 75%, the reaction liquid is transferred to the devolatilizer for devolatilization. The devolatilization is continuously operated for 1 hour, and then samples are taken to test various indicators of the obtained high-heat-resistant and high-impact strength polystyrene.

[0049] Example 3

[0050] A method for preparing high-heat-resistant and high-impact-strength polystyrene comprises the following steps: 1. Mix styrene monomer, toluene, methanol, rubber 255P, antioxidant 1076 and white oil. After the rubber is completely dissolved, add tert-butyl peroxyisopropyl carbonate and zinc stearate to the rubber solution to obtain a mixed solution. Figure 1In the middle flow chart, the reaction liquid is passed into the primary reactor R1 for prepolymerization at a temperature of 120°C. After the conversion rate reaches 30%, the reaction liquid is passed into the secondary reactor R2; Among them, the mass ratio of styrene monomer, solvent (toluene: methanol = 4:1), rubber 255P, antioxidant 1076, white oil, tert-butyl peroxyisopropyl carbonate and zinc stearate is 100:5:6:0.1:1:0.01:0.1.

[0051] 2. The reaction temperature in the secondary reactor R2 is 140°C. After the reaction reaches a conversion rate of 60%, the reaction liquid is passed into the tertiary reactor R3; 3. The reaction temperature in the tertiary reactor R3 is 152°C. After the reaction is carried out until the conversion rate of the reaction liquid reaches 75%, the reaction liquid is transferred to the devolatilizer for devolatilization. The devolatilization is continuously operated for 1 hour, and then samples are taken to test various indicators of the obtained high-heat-resistant and high-impact strength polystyrene.

[0052] Example 4

[0053] A method for preparing high-heat-resistant and high-impact-strength polystyrene comprises the following steps: 1. Mix styrene monomer, toluene, methanol, rubber 255P, antioxidant 1076 and white oil. After the rubber is completely dissolved, add tert-butyl peroxyisopropyl carbonate and zinc stearate to the rubber solution to obtain a mixed solution. Figure 1 In the middle flow chart, the reaction liquid is passed into the primary reactor R1 for prepolymerization at a temperature of 140°C. After the conversion rate reaches 30%, the reaction liquid is passed into the secondary reactor R2; Among them, the mass ratio of styrene monomer, solvent (toluene: methanol = 1:4), rubber 255P, antioxidant 1076, white oil, tert-butyl peroxyisopropyl carbonate and zinc stearate is 100:5:6:0.1:1:0.01:0.1.

[0054] 2. The reaction temperature in the secondary reactor R2 is 140°C. After the reaction reaches a conversion rate of 60%, the reaction liquid is passed into the tertiary reactor R3; 3. The reaction temperature in the tertiary reactor R3 is 140°C. After the reaction is carried out until the conversion rate of the reaction liquid reaches 75%, the reaction liquid is transferred to the devolatilizer for devolatilization. The devolatilization is continuously operated for 48 hours, and then samples are taken to test various indicators of the obtained high-heat-resistant and high-impact strength polystyrene.

[0055] Comparative Example 1 A method for preparing high-heat-resistant and high-impact-strength polystyrene comprises the following steps: 1. Mix styrene monomer, ethylbenzene, rubber 255P, antioxidant 1076 and white oil. After the rubber is completely dissolved, add tert-butyl peroxyisopropyl carbonate and zinc stearate to the rubber solution to obtain a mixed solution. Figure 1 In the middle flow chart, the reaction liquid is passed into the primary reactor R1 for prepolymerization at a temperature of 120°C. After the conversion rate reaches 30%, the reaction liquid is passed into the secondary reactor R2; The mass ratio of styrene monomer, ethylbenzene, rubber 255P, antioxidant 1076, white oil, tert-butyl peroxyisopropyl carbonate and zinc stearate is 100:5:6:0.1:1:0.01:0.1.

[0056] 2. The reaction temperature in the secondary reactor R2 is 140°C. After the reaction reaches a conversion rate of 60%, the reaction liquid is passed into the tertiary reactor R3; 3. The reaction temperature in the tertiary reactor R3 is 152°C. After the reaction is carried out until the conversion rate of the reaction liquid reaches 75%, the reaction liquid is transferred to the devolatilizer for devolatilization. The devolatilization is continuously operated for 48 hours, and then samples are taken to test various indicators of the prepared polystyrene.

[0057] Comparative Example 2 A method for preparing high-heat-resistant and high-impact-strength polystyrene comprises the following steps: 1. Mix styrene monomer, toluene, rubber 255P, antioxidant 1076 and white oil. After the rubber is completely dissolved, add tert-butyl peroxyisopropyl carbonate and zinc stearate to the rubber solution to obtain a mixed solution. Figure 1 In the middle flow chart, the reaction liquid is passed into the primary reactor R1 for prepolymerization at a temperature of 120°C. After the conversion rate reaches 30%, the reaction liquid is passed into the secondary reactor R2; The mass ratio of styrene monomer, toluene, rubber 255P, antioxidant 1076, white oil, tert-butyl peroxyisopropyl carbonate and zinc stearate is 100:5:6:0.1:1:0.01:0.1.

[0058] 2. The reaction temperature in the secondary reactor R2 is 140°C. After the reaction reaches a conversion rate of 60%, the reaction liquid is passed into the tertiary reactor R3; 3. The reaction temperature in the tertiary reactor R3 is 152°C. After the reaction is carried out until the conversion rate of the reaction liquid reaches 75%, the reaction liquid is transferred to the devolatilizer for devolatilization. The devolatilization is continuously operated for 1 hour, and then samples are taken to test various indicators of the prepared polystyrene.

[0059] Test method: The molecular weight and molecular weight distribution were determined using gel permeation chromatography (GPC) with tetrahydrofuran as the solvent. Vicat softening point was carried out according to ISO306, with a pressure of 50N and a heating rate of 50°C / min; The melt flow rate is tested according to ISO1133, the test temperature is 200℃, and the weight is 5kg; With reference to GB / T 1043.1-2008, the impact strength of the polystyrenes prepared in the examples and comparative examples was tested.

[0060] The test results are shown in Table 1.

[0061] Table 1 Test results of various embodiments and comparative examples

[0062] As can be seen from the examples and comparative examples, in the polystyrene production process, adding some methanol to toluene or ethylbenzene as a reaction solvent. Above 120°C, the mixed solvent of methanol and aromatic hydrocarbons has better solubility for the polymer, the effect of the mixed reaction is better, and it is more conducive to the removal of reaction heat. However, since the polymerization reaction is an exothermic reaction, if the reaction heat is not removed in time, the system temperature will rise. As the temperature rises, the molecular thermal motion intensifies, the frequency and energy of intermolecular collisions increase, making it easier for the polymer molecular chains to entangle and interact, thereby increasing the viscosity of the system. It is precisely because adding some methanol to toluene or ethylbenzene as a reaction solvent is conducive to removing the reaction heat that the system temperature can be kept relatively stable, the intensity of the molecular thermal motion is controlled, the entanglement and interaction between the molecular chains are reduced, and the viscosity of the system is reduced. Therefore, the overall melt flow rate of Examples 1 to 4 is higher than that of the comparative example. At the same time, the removal of the reaction heat can prevent the reaction system temperature from being too high, thereby triggering some side reactions such as branching and cross-linking. This makes the prepared polystyrene have a narrow molecular weight distribution, high heat resistance and high impact strength, which is reflected in that the molecular weight distribution values ​​of Examples 1 to 4 are all lower than those of the comparative example, while the impact strength and Vicat softening point are all higher than those of the comparative example.

[0063] The above results show and describe the basic principles and main features of this application as well as the advantages of this application.

[0064] Those skilled in the art should understand that the present application is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. Such changes and improvements are intended to fall within the scope of the present application. The scope of protection claimed in the present application is defined by the equivalents of the appended claims.

Claims

1. A method for preparing high heat-resistant and high impact strength polystyrene, characterized in that: The steps include: The reaction liquid consisting of vinyl aromatic monomer, solvent, polybutadiene rubber and additives is continuously transported to a multi-stage series reactor group; the solvent is a mixture of ethylbenzene and methanol or toluene and methanol in any proportion; After the reaction is completed, the reaction liquid output from the last reactor in the multi-stage series reactor group is transferred to a devolatilizer for devolatilization to obtain high heat-resistant and high impact strength polystyrene.

2. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 1, characterized in that: The auxiliary agent includes an initiator, a plasticizer, an antioxidant and a lubricant; the mass ratio of the vinyl aromatic monomer, the solvent, the polybutadiene rubber, the antioxidant, the plasticizer, the initiator and the lubricant is 100: (3-10): (6-7): (0.5-2): (1-2): (0.01-0.02): (0.05-0.2).

3. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 1, characterized in that: The reaction temperature in each stage of the multi-stage series reactor group is the same or different.

4. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 3, characterized in that: If the reaction temperature in each reactor of the multi-stage series reactor group is different, there are at least two reactors in the multi-stage series reactor group, and the reaction temperature in the relatively later reactor of the two reactors is greater than the reaction temperature in the relatively earlier reactor.

5. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 4, characterized in that: The two-stage reactors are adjacent or non-adjacent.

6. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 1, characterized in that: Each reactor in the multi-stage series reactor group is independently a plug flow reactor or a stirred tank reactor.

7. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 1, characterized in that: For any two adjacent reactors in the multi-stage series reactor group, the condition for the reaction liquid to be transported from the adjacent previous reactor to the adjacent next reactor or devolatilizer is that the reaction liquid in the adjacent previous reactor is within the corresponding set conversion rate threshold range.

8. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 1, characterized in that: The vinyl aromatic monomer includes at least one of styrene and α-methylstyrene.

9. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 1, characterized in that: The polybutadiene rubber includes at least one of low-cis polybutadiene rubber and high-cis polybutadiene rubber.

10. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 1, characterized in that: The auxiliary agents include initiators and plasticizers.

11. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 1, characterized in that: The molecular weight distribution range of the high heat-resistant and high impact strength polystyrene is 1.5-2.

0.

12. The method for preparing high heat-resistant and high impact strength polystyrene according to claim 1, characterized in that: The Vicat softening point of the high heat-resistant and high impact strength polystyrene is not less than 90°C.

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