Quadripolymer containing N-phenylmaleimide, synthetic method and application

Abstract

The invention discloses a quadripolymer containing N-phenylmaleimide. The quadripolymer is prepared from the following components in parts by weight: 5 to 40 parts of N-phenylmaleimide, 5 to 30 parts of alpha-methyl styrene, 30 to 90 parts of other monomers, 100 to 300 parts of deionized water, 1 to 5 parts of initiator, 1 to 5 parts of electrolyte compound and 1 to 5 parts of emulsifier. The invention belongs to the technical field of high polymer material synthesis, and particularly relates to a quadripolymer containing N-phenylmaleimide, and the prepared quadripolymer heat-resistant modifier containing N-phenylmaleimide has the advantages of high yield (greater than or equal to 98%), low NPMI monomer dosage (less than or equal to 10 mol.%), high glass transition temperature (greater than or equal to 140 DEG C), good compatibility with PVC (polyvinyl chloride) resin, good heat-resistant property, good heat-resistant property and good heat-resistant property. The synthesis route is simple and environment-friendly, the heat-resistant modification effect is extremely excellent (the temperature can be increased by 40 DEG C or above), and the heat-resistant modifier material can be used as a PVC resin heat-resistant modifier material.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material synthesis, and particularly relates to a tetrapolymer containing N-phenylmaleimide, a synthesis method and application thereof as a heat-resistant modifier for PVC resin. Background Art

[0002] Polyvinyl chloride (PVC) resin has a wide range of raw materials, mature preparation and processing technology, low product price, good comprehensive mechanical properties, chemical corrosion resistance, flame retardancy, and excellent electrical insulation properties. It is widely used in industrial production and life. Among the five general-purpose plastics, its usage is second only to polyethylene, but PVC resin has poor heat resistance, and the maximum continuous use temperature is only 60-70°C, which greatly limits the expansion of its application range. Therefore, on the basis of not significantly increasing the cost of the product, increasing the heat resistance temperature of PVC resin, expanding its application field, and replacing some expensive engineering plastics has great practical value and can produce significant economic benefits.

[0003] By compounding with ABS, ACR (acrylic ester copolymer), SAM (styrene-acrylonitrile-maleic anhydride copolymer) and other resins, some properties of PVC resin can be improved, but the heat resistance modification effect is not ideal; by chlorination of PVC (CPVC), the glass transition temperature (T g ) has been improved, but the problems of poor thermal stability and impact resistance still exist, and the price is high and processing is difficult; research shows that the use of N-phenylmaleimide (NPMI) as a heat-resistant copolymer modifier and PVC compounding will give PVC resin good comprehensive properties. NPMI is difficult to homopolymerize, and is generally copolymerized with other monomers to form random copolymers. By adjusting the polymerization method, selecting the appropriate polymerization mechanism and monomer ratio, adjusting the reaction conditions, etc., the molecular structure, morphology and physical properties of the copolymer are designed, and a heat-resistant modifier with good compatibility with PVC resin and good comprehensive performance can be synthesized.

[0004] The existing patented technology uses seed microemulsion polymerization to synthesize NPMI-AN-St (PNAS) ternary copolymer nano latex. When the PNAS dosage is 50wt.%, the T of PNAS / PVC composite material is gCompared with pure PVC, it is increased by 22.4℃, and the heat resistance modification effect is good. The disadvantage is that the amount of NPMI monomer is large, the cost is high, and the impact performance of PVC resin is greatly deteriorated; NPMI, styrene, acrylonitrile, and α-methylstyrene are used as reaction monomers, and the quaternary copolymer is synthesized by emulsion polymerization. When the addition amount is 30 parts, the Vicat softening temperature of PVC resin is increased by 18.9℃. Although the overall effect is excellent, the heat resistance of the material is still far from the use requirements; the rare earth-containing N-substituted maleimide quaternary copolymer is synthesized by emulsion polymerization, and the blending modification of PVC The Vicat softening point is 4.7℃ higher than that of pure PVC, and the modification effect is not good. NPMI, α-methylstyrene and methyl methacrylate are used as reaction monomers to prepare terpolymers by step-by-step emulsion polymerization for heat-resistant modification of PVC, but the production steps are relatively complicated and the cost of spray drying is high, which is not conducive to the control of product costs. At present, my country's PVC resin heat-resistant modifier market is still dominated by foreign products, such as the heat-resistant products of Nippon Catalyst and Nippon Denka. How to solve the high dependence on foreign products and realize the localization of PVC resin heat-resistant modifiers is a problem that needs to be solved.

[0005] It can be seen from the literature that the existing domestic PVC heat-resistant modifiers have the disadvantages of high product cost, unclear heat-resistant modification effect, and large impact performance degradation. Based on the above problems, how to prepare a heat-resistant modifier with high yield, high glass transition temperature, certain molecular weight and distribution, and excellent compatibility with PVC resin by a simple, mature and environmentally friendly polymerization method at a lower dosage of NPMI is an industry problem in the field of domestic PVC resin heat-resistant modifiers. The present invention adopts the method of seed microemulsion polymerization, combined with semi-continuous feeding, and introduces NMPI and α-methylstyrene monomers through the reasonable design of polymerization method, reaction monomers and reaction conditions. Under the condition of low NPMI monomer dosage, a tetrapolymer with excellent heat-resistant modification effect on PVC resin is synthesized, and related research has not been reported yet. Summary of the invention

[0006] In order to solve the deficiencies of the prior art, the primary purpose of the present invention is to provide a tetrapolymer containing N-phenylmaleimide and a synthesis method. The present invention selects a relatively environmentally friendly and simple-to-operate microemulsion seed polymerization, combines a semi-continuous feeding method to synthesize an N-phenylmaleimide tetrapolymer nanoemulsion with uniform particle size and consistent molecular structure, and regulates the glass transition temperature and solubility parameter of the copolymer by modifying the type and ratio of the monomers. The finally synthesized N-phenylmaleimide tetrapolymer has a high yield (≥98%) of a heat-resistant modifier, a low amount of NPMI monomer (≤10 mol.%), a high glass transition temperature (≥140° C.), and good compatibility with PVC resin. The synthesis route is relatively simple and environmentally friendly, and the heat-resistant modification effect is extremely excellent (can be increased by more than 40° C.), and can be used as a heat-resistant modifier material for PVC resin.

[0007] The technical solution adopted by the present invention is as follows: the present invention provides a tetrapolymer containing N-phenylmaleimide, comprising the following components in parts by weight: 5-40 parts of N-phenylmaleimide, 5-30 parts of α-methylstyrene, 30-90 parts of other monomers, 100-300 parts of deionized water, 1-5 parts of initiator, 1-5 parts of electrolyte compound, and 1-5 parts of emulsifier.

[0008] Furthermore, the present invention provides a tetrapolymer containing N-phenylmaleimide, which comprises the following components in parts by weight: 10-20 parts of N-phenylmaleimide, 10-20 parts of α-methylstyrene, 50-80 parts of other monomers, 120-280 parts of deionized water, 2-4 parts of initiator, 2-4 parts of electrolyte compound, and 2-4 parts of emulsifier.

[0009] Furthermore, the present invention provides a tetrapolymer containing N-phenylmaleimide, which includes the following components in parts by weight: 10 parts of N-phenylmaleimide, 10 parts of α-methylstyrene, 80 parts of other monomers, 200 parts of deionized water, 2 parts of initiator, 3 parts of electrolyte compound, and 2 parts of emulsifier.

[0010] A method for synthesizing a tetrapolymer containing N-phenylmaleimide comprises the following steps:

[0011] Step 1: Add a certain amount of emulsifier into deionized water and stir until the emulsifier is completely dissolved in the water;

[0012] Step 2: Mixing measured amounts of N-phenylmaleimide, α-methylstyrene and other monomers;

[0013] Step 3: Pour the mixture in step 2 into the emulsifier solution in step 1, and stir at high speed until a uniform light yellow pre-emulsion is formed;

[0014] Step 4: Take part of the above pre-emulsion and all the initiators, transfer them into a four-necked flask, and polymerize them at a certain temperature for 10 minutes to form a seed emulsion;

[0015] Step 5: Add the remaining pre-emulsion dropwise into the four-necked bottle to continue polymerization, and control the reaction temperature and the dropwise acceleration rate; after the dropwise addition is completed, keep the temperature for reaction for 1 hour to synthesize a tetrapolymer nanoemulsion containing N-phenylmaleimide;

[0016] Step 6: Take a certain amount of electrolyte compound and dissolve it in deionized water to prepare an electrolyte solution of a certain concentration;

[0017] Step 7: diluting the tetrapolymer emulsion synthesized in step 5 and adding it into a certain amount of electrolyte solution, stirring to break the emulsion, aging, centrifuging, washing, and drying to prepare a white powdery N-phenylmaleimide tetrapolymer material;

[0018] Step 8: Mix the synthesized N-phenylmaleimide tetrapolymer with PVC resin and additives according to a ratio, extrude and granulate in an extruder, and then transfer the granules to an injection molding machine for injection molding.

[0019] Furthermore, the emulsifier described in step one is a composite emulsifier of anionic emulsifier and nonionic emulsifier, wherein the anionic emulsifier is one or more of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, stearate, and oleate, and the nonionic emulsifier is one or more of dodecylphenol polyoxyethylene ether, polysorbates, alkylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether.

[0020] Furthermore, in step 2, other monomers are any two of vinyl chloride, styrene, methyl methacrylate, methyl acrylate, acrylonitrile, and maleic anhydride, and the mass ratio of the monomers to water is 1:1 to 1:3.

[0021] Furthermore, the initiator used in step 4 is one or more of potassium persulfate, ammonium persulfate, water-soluble azo initiator, benzoyl peroxide, hydrogen peroxide, and hydroperoxide.

[0022] Furthermore, in step 3, step 4 and step 5, the polymerization temperature ranges from 50 to 90° C., and the stirring speed ranges from 120 to 480 rpm;

[0023] Furthermore, in step 1, the emulsifier is an ionic emulsifier and a non-ionic emulsifier in a weight ratio of 1:1 to 5:1.

[0024] The invention also relates to the application of the N-phenylmaleimide tetrapolymer as a heat-resistant modifier for PVC resin.

[0025] After adopting the above technical scheme, the beneficial effects of the present invention are as follows: a relatively environmentally friendly and simple-to-operate microemulsion seed polymerization is selected, and a semi-continuous feeding method is combined to synthesize an N-phenylmaleimide tetrapolymer nanoemulsion with uniform particle size and consistent molecular structure, and the glass transition temperature and solubility parameter of the copolymer are regulated by modifying the type and ratio of the monomers. The finally synthesized N-phenylmaleimide tetrapolymer heat-resistant modifier has a high yield (≥98%), a low NPMI monomer dosage (≤10 mol.%), a high glass transition temperature (≥140°C), and good compatibility with PVC resin. The synthetic route is relatively simple and environmentally friendly, and the heat-resistant modification effect is extremely excellent (can be increased by more than 40°C), and can be used as a heat-resistant modifier material for PVC resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 DSC spectra of the tetrapolymers at different NPMI monomer dosages;

[0027] Figure 2 The DSC spectra of PVC resin under different heat-resistant agent dosages;

[0028] Figure 3 It is a schematic diagram of the Vicat softening point temperature of PVC resin under different heat-resistant agent dosages;

[0029] Figure 4 is the GPC spectrum of the tetrapolymer;

[0030] Figure 5 The figure is the mechanical properties of PVC resin under different heat-resistant agent dosage;

[0031] Figure 6 SEM images of the tetrapolymer at different magnifications: (a) 50,000 times; (b) 50,000 times; (c) 100,000 times. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] The overall technical solution of the present invention is first described below.

[0034] The invention discloses a tetrapolymer containing N-phenylmaleimide, which comprises the following components in parts by weight: 5-40 parts of N-phenylmaleimide, 5-30 parts of alpha-methylstyrene, 30-90 parts of other monomers, 100-300 parts of deionized water, 1-5 parts of initiator, 1-5 parts of electrolyte compound and 1-5 parts of emulsifier.

[0035] When the above-mentioned substances are used to prepare the tetrapolymer of N-phenylmaleimide, the following preparation steps are included:

[0036] Step 1: Add a certain amount of emulsifier into deionized water and stir until the emulsifier is completely dissolved in the water;

[0037] Step 2: Mixing measured amounts of N-phenylmaleimide, α-methylstyrene and other monomers;

[0038] Step 3: Pour the mixture in step 2 into the emulsifier solution in step 1, and stir at high speed until a uniform light yellow pre-emulsion is formed;

[0039] Step 4: Take part of the above pre-emulsion and all the initiators, transfer them into a four-necked flask, and polymerize them at a certain temperature for 10 minutes to form a seed emulsion;

[0040] Step 5: Add the remaining pre-emulsion dropwise into the four-necked bottle to continue polymerization, and control the reaction temperature and the dropwise acceleration rate; after the dropwise addition is completed, keep the temperature for reaction for 1 hour to synthesize a tetrapolymer nanoemulsion containing N-phenylmaleimide;

[0041] Step 6: Take a certain amount of electrolyte compound and dissolve it in deionized water to prepare an electrolyte solution of a certain concentration;

[0042] Step 7: diluting the tetrapolymer emulsion synthesized in step 5 and adding it into a certain amount of electrolyte solution, stirring to break the emulsion, aging, centrifuging, washing, and drying to prepare a white powdery N-phenylmaleimide tetrapolymer material;

[0043] Step 8: Mix the synthesized N-phenylmaleimide tetrapolymer with PVC resin and additives according to a ratio, extrude and granulate in an extruder, and then transfer the granules to an injection molding machine for injection molding.

[0044] Next, the present invention is described in detail through specific embodiments.

[0045] Example 1

[0046] Take 2% of the monomer mass of the emulsifier, dissolve it in deionized water after compounding, and set aside; then weigh NPMI and other reaction monomers according to the ratio, wherein NPMI accounts for 0% of the monomer molar ratio, α-methylstyrene accounts for 10% of the monomer molar ratio, methyl methacrylate accounts for 20%, and styrene accounts for 70%, stir and mix the reaction monomers evenly, and then pour them into the above emulsifier solution, stir and disperse at high speed for 20 minutes, until a stable light yellow pre-emulsion is formed; take part of the pre-emulsion and all the initiators, put them into a four-necked bottle, stir and react for 15 minutes, the reaction temperature is 80°C, to generate a seed emulsion, and then drop the remaining pre-emulsion into the seed emulsion drop by drop to continue the reaction, after the dropwise addition is completed, keep the temperature for reaction for 1 hour, and prepare an N-phenylmaleimide tetrapolymer nanoemulsion; demulsify the above prepared emulsion with an electrolyte solution, filter, wash, and dry, and finally prepare a powdered N-phenylmaleimide tetrapolymer heat-resistant modifier.

[0047] Example 2

[0048] Take an emulsifier with a weight of 2% of the monomer, dissolve it in deionized water after compounding, and set aside; weigh NPMI and other reaction monomers according to the ratio, wherein NPMI accounts for 5% of the monomer molar ratio, α-methylstyrene accounts for 10% of the monomer molar ratio, methyl methacrylate accounts for 20%, and styrene accounts for 65%, stir and mix the reaction monomers evenly, and then pour them into the above emulsifier solution, stir and disperse at high speed for 20 minutes, until a stable light yellow pre-emulsion is formed; take part of the pre-emulsion and all the initiators, put them into a four-necked bottle, stir and react for 15 minutes, the reaction temperature is 80°C, and a seed emulsion is generated, and then the remaining pre-emulsion is dripped into the seed emulsion drop by drop to continue the reaction. After the dripping is completed, the reaction is kept warm for 1 hour to prepare an N-phenylmaleimide tetrapolymer nanoemulsion; the prepared emulsion is demulsified with an electrolyte solution, filtered, washed, and dried to finally prepare a powdered N-phenylmaleimide tetrapolymer heat-resistant modifier.

[0049] Example 3

[0050] Take an emulsifier with a weight of 2% of the monomer, dissolve it in deionized water after compounding, and set it aside; weigh NPMI and other reaction monomers according to the ratio, wherein NPMI accounts for 7.5% of the monomer molar ratio, α-methylstyrene accounts for 10% of the monomer molar ratio, methyl methacrylate accounts for 20%, and styrene accounts for 62.5%, stir and mix the reaction monomers evenly, and then pour them into the above emulsifier solution, stir and disperse them at high speed for 20 minutes, until a stable light yellow pre-emulsion is formed; take part of the pre-emulsion and all the initiators, put them into a four-necked bottle, stir and react for 15 minutes, the reaction temperature is 80°C, and a seed emulsion is generated, and then the remaining pre-emulsion is dripped into the seed emulsion drop by drop to continue the reaction. After the dripping is completed, the reaction is kept warm for 1 hour to prepare an N-phenylmaleimide tetrapolymer nanoemulsion; the prepared emulsion is demulsified with an electrolyte solution, filtered, washed, and dried to finally prepare a powdered N-phenylmaleimide tetrapolymer heat-resistant modifier.

[0051] Example 4

[0052] Take an emulsifier with a weight of 2% of the monomer, dissolve it in deionized water after compounding, and set it aside; weigh NPMI and other reaction monomers according to the ratio, wherein NPMI accounts for 10% of the monomer molar ratio, α-methylstyrene accounts for 10% of the monomer molar ratio, methyl methacrylate accounts for 20%, and styrene accounts for 60%, stir and mix the reaction monomers evenly, and then pour them into the above emulsifier solution, stir and disperse them at high speed for 20 minutes, until a stable light yellow pre-emulsion is formed; take part of the pre-emulsion and all the initiators, put them into a four-necked bottle, stir and react for 15 minutes, the reaction temperature is 80°C, and a seed emulsion is generated, and then the remaining pre-emulsion is dripped into the seed emulsion drop by drop to continue the reaction. After the dripping is completed, the reaction is kept warm for 1 hour to prepare an N-phenylmaleimide tetrapolymer nanoemulsion; the prepared emulsion is demulsified with an electrolyte solution, filtered, washed, and dried to finally prepare a powdered N-phenylmaleimide tetrapolymer heat-resistant modifier.

[0053] Table 1 Glass transition temperature of N-phenylmaleimide tetrapolymer under the above different examples

[0054]

[0055] Example 5

[0056] Take an emulsifier with a weight of 2% of the monomer, dissolve it in deionized water after compounding, and set aside; weigh NPMI and other reaction monomers according to the ratio, wherein NPMI accounts for 10% of the monomer molar ratio, α-methylstyrene accounts for 10% of the monomer molar ratio, methyl methacrylate accounts for 10%, and styrene accounts for 70%, stir and mix the reaction monomers evenly, and then pour them into the above emulsifier solution, stir and disperse at high speed for 20 minutes, until a stable light yellow pre-emulsion is formed; take part of the pre-emulsion and all the initiators, put them into a four-necked bottle, stir and react for 15 minutes, the reaction temperature is 80°C, and a seed emulsion is generated, and then the remaining pre-emulsion is dripped into the seed emulsion to continue the reaction. After the dripping is completed, the reaction is kept warm for 1 hour to prepare an N-phenylmaleimide tetrapolymer nanoemulsion; the prepared emulsion is demulsified with an electrolyte solution, filtered, washed, and dried to finally prepare a powdered N-phenylmaleimide tetrapolymer heat-resistant modifier.

[0057] Example 6

[0058] Take an emulsifier with a weight of 2% of the monomer, dissolve it in deionized water after compounding, and set aside; weigh NPMI and other reaction monomers according to the ratio, wherein NPMI accounts for 10% of the monomer molar ratio, α-methylstyrene accounts for 10% of the monomer molar ratio, methyl methacrylate accounts for 30%, and styrene accounts for 50%, stir and mix the reaction monomers evenly, and then pour them into the above emulsifier solution, stir and disperse at high speed for 20 minutes, until a stable light yellow pre-emulsion is formed; take part of the pre-emulsion and all the initiators, put them into a four-necked bottle, stir and react for 15 minutes, the reaction temperature is 80°C, and a seed emulsion is generated, and then the remaining pre-emulsion is dripped into the seed emulsion to continue the reaction. After the dripping is completed, the reaction is kept warm for 1 hour to prepare an N-phenylmaleimide tetrapolymer nanoemulsion; the prepared emulsion is demulsified with an electrolyte solution, filtered, washed, and dried to finally prepare a powdered N-phenylmaleimide tetrapolymer heat-resistant modifier.

[0059] Example 7

[0060] Take an emulsifier with a weight of 2% of the monomer, dissolve it in deionized water after compounding, and set aside; weigh NPMI and other reaction monomers according to the ratio, wherein NPMI accounts for 10% of the monomer molar ratio, α-methylstyrene accounts for 10% of the monomer molar ratio, methyl methacrylate accounts for 40%, and styrene accounts for 40%, stir and mix the reaction monomers evenly, and then pour them into the above emulsifier solution, stir and disperse at high speed for 20 minutes, until a stable light yellow pre-emulsion is formed; take part of the pre-emulsion and all the initiators, put them into a four-necked bottle, stir and react for 15 minutes, the reaction temperature is 80°C, and a seed emulsion is generated, and then the remaining pre-emulsion is dripped into the seed emulsion drop by drop to continue the reaction. After the dripping is completed, the reaction is kept warm for 1 hour to prepare an N-phenylmaleimide tetrapolymer nanoemulsion; the prepared emulsion is demulsified with an electrolyte solution, filtered, washed, and dried to finally prepare a powdered N-phenylmaleimide tetrapolymer heat-resistant modifier.

[0061] Table 2 Heat resistance modification effect of NPMI tetrapolymer under different monomer ratios

[0062]

[0063] Example 8

[0064] The N-phenylmaleimide tetrapolymer prepared in Example 7 is mixed with PVC resin and additives according to the ratio, wherein the N-phenylmaleimide tetrapolymer is 0 parts, the PVC resin is 100 parts, the composite calcium zinc stabilizer is 10 parts, the plasticizer DOP is 5 parts, the antioxidant 10100.4 parts, and the internal lubricant stearic acid is 1 part. After mixing, it is mixed in an internal mixer at a mixing temperature of 175°C and a mixing time of 5 minutes. Then, the mixed and plasticized material is molded in a flat vulcanizer at a molding pressure of 10MPa, a molding temperature of 180°C, and a molding time of 5 minutes. Then, the molded sample is cut according to the national standard and the relevant properties are measured.

[0065] Example 9

[0066] The N-phenylmaleimide tetrapolymer prepared in Example 7 is mixed with PVC resin and additives according to the ratio, wherein the N-phenylmaleimide tetrapolymer is 10 parts, the PVC resin is 90 parts, the composite calcium zinc stabilizer is 10 parts, the plasticizer DOP is 5 parts, the antioxidant 10100.4 parts, and the internal lubricant stearic acid is 1 part. After mixing, it is mixed in an internal mixer at a mixing temperature of 175° C. for 5 minutes, and then the mixed and plasticized material is molded in a flat vulcanizer at a molding pressure of 10 MPa, a molding temperature of 180° C., and a molding time of 5 minutes. Then the molded sample is cut according to the national standard and the relevant properties are measured.

[0067] Example 10

[0068] The N-phenylmaleimide tetrapolymer prepared in Example 7 is mixed with PVC resin and additives according to the ratio, wherein the N-phenylmaleimide tetrapolymer is 20 parts, the PVC resin is 80 parts, the composite calcium zinc stabilizer is 10 parts, the plasticizer DOP is 5 parts, the antioxidant 10100.4 parts, and the internal lubricant stearic acid is 1 part. After mixing, it is mixed in an internal mixer at a mixing temperature of 175° C. and a mixing time of 5 minutes. Subsequently, the mixed and plasticized material is molded in a flat vulcanizer at a molding pressure of 10 MPa, a molding temperature of 180° C., and a molding time of 5 minutes. Subsequently, the molded sample is cut according to the national standard and the relevant properties are measured.

[0069] Embodiment 11

[0070] The N-phenylmaleimide tetrapolymer prepared in Example 7 is mixed with PVC resin and additives according to the ratio, wherein the N-phenylmaleimide tetrapolymer is 30 parts, the PVC resin is 70 parts, the composite calcium zinc stabilizer is 10 parts, the plasticizer DOP is 5 parts, the antioxidant 10100.4 parts, and the internal lubricant stearic acid is 1 part. After mixing, it is mixed in an internal mixer at a mixing temperature of 175° C. and a mixing time of 5 minutes. Subsequently, the mixed and plasticized material is molded in a flat vulcanizer at a molding pressure of 10 MPa, a molding temperature of 180° C., and a molding time of 5 minutes. Subsequently, the molded sample is cut according to the national standard and the relevant properties are measured.

[0071] Table 3 Related performance data of modified PVC resin in the above embodiment

[0072]

[0073] The present invention and its embodiments are described above, but such description is not restrictive. What is shown in the specification is only part of the embodiments of the present invention, and the actual method is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A tetrapolymer containing N-phenylmaleimide, characterized in that: The invention comprises the following components in parts by weight: 5-40 parts of N-phenylmaleimide, 5-30 parts of alpha-methylstyrene, 30-90 parts of other monomers, 100-300 parts of deionized water, 1-5 parts of initiator, 1-5 parts of electrolyte compound and 1-5 parts of emulsifier.

2. A tetrapolymer containing N-phenylmaleimide according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 10-20 parts of N-phenylmaleimide, 10-20 parts of alpha-methylstyrene, 50-80 parts of other monomers, 120-280 parts of deionized water, 2-4 parts of initiator, 2-4 parts of electrolyte compound and 2-4 parts of emulsifier.

3. A tetrapolymer containing N-phenylmaleimide according to claim 1-2, characterized in that: The invention comprises the following components in parts by weight: 10 parts of N-phenylmaleimide, 10 parts of alpha-methylstyrene, 80 parts of other monomers, 200 parts of deionized water, 2 parts of initiator, 3 parts of electrolyte compound and 2 parts of emulsifier.

4. A method for synthesizing a tetrapolymer containing N-phenylmaleimide according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Add a certain amount of emulsifier into deionized water and stir until the emulsifier is completely dissolved in the water; Step 2: Mixing measured amounts of N-phenylmaleimide, α-methylstyrene and other monomers; Step 3: Pour the mixture in step 2 into the emulsifier solution in step 1, and stir at high speed until a uniform light yellow pre-emulsion is formed; Step 4: Take part of the above pre-emulsion and all the initiators, transfer them into a four-necked flask, and polymerize them at a certain temperature for 10 minutes to form a seed emulsion; Step 5: Add the remaining pre-emulsion dropwise into the four-necked bottle to continue polymerization, and control the reaction temperature and the dropwise acceleration rate; after the dropwise addition is completed, keep the temperature for reaction for 1 hour to synthesize a tetrapolymer nanoemulsion containing N-phenylmaleimide; Step 6: Take a certain amount of electrolyte compound and dissolve it in deionized water to prepare an electrolyte solution of a certain concentration; Step 7: diluting the tetrapolymer emulsion synthesized in step 5 and adding it into a certain amount of electrolyte solution, stirring to break the emulsion, aging, centrifuging, washing, and drying to prepare a white powdery N-phenylmaleimide tetrapolymer material; Step 8: Mix the synthesized N-phenylmaleimide tetrapolymer with PVC resin and additives according to a ratio, extrude and granulate in an extruder, and then transfer the granules to an injection molding machine for injection molding.

5. The synthesis method according to claim 4, characterized in that The emulsifier described in step 1 is a composite emulsifier of anionic emulsifier and nonionic emulsifier, wherein the anionic emulsifier is one or more of sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, stearate, and oleate, and the nonionic emulsifier is one or more of dodecylphenol polyoxyethylene ether, polysorbates, alkylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether.

6. The synthesis method according to claim 4, characterized in that In step 1, the emulsifier is an ionic emulsifier and a non-ionic emulsifier in a weight ratio of 1:1 to 5:

1.

7. The synthesis method according to claim 4, characterized in that In step 2, the other monomers are any two of vinyl chloride, styrene, methyl methacrylate, methyl acrylate, acrylonitrile and maleic anhydride, and the mass ratio of the monomers to water is 1:1 to 1:

3.

8. The synthesis method according to claim 4, characterized in that In step 3, step 4 and step 5, the polymerization temperature ranges from 50 to 90° C., and the stirring rate ranges from 120 to 480 rpm.

9. The synthesis method according to claim 4, characterized in that The initiator used in step 4 is one or more of potassium persulfate, ammonium persulfate, water-soluble azo initiator, benzoyl peroxide, hydrogen peroxide, and hydroperoxide.

10. Use of the N-phenylmaleimide tetrapolymer according to any one of claims 1 to 3 as a heat-resistant modifier for PVC resin.

Images