A heat-resistant modifier for PVC materials and its preparation method

Abstract

This application provides a heat-resistant modifier specifically for PVC materials. By weight, the raw materials for preparing the heat-resistant modifier include: 3-22 parts of organosilicon molecules, 70-150 parts of reactive monomers, 0.1-2 parts of molecular weight regulator, 0.5-4 parts of emulsifier, and 0.05-1 part of initiator. By introducing suitable types and amounts of organosilicon monomers and optimizing the different types and amounts of reactive monomers, the combined effect of these components not only increases the glass transition temperature of the modifier and PVC products but also improves the processing performance of PVC products, avoiding problems such as sticking and color difference. Compared with excellent foreign modifier products, the modifier in this application still significantly improves the performance of PVC products even with small amounts added, reducing the amount of modifier used in PVC products, greatly reducing production costs. Furthermore, it can increase the plasticizing speed of PVC, playing a role in energy conservation and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, C08G77 / 14, and particularly to a heat-resistant modifier for PVC materials and its preparation method. Background Technology

[0002] PVC is one of the most produced general-purpose thermoplastics in my country, and its products are used in many fields such as industry, agriculture, packaging, power, and building materials. However, current PVC resin also has many shortcomings: pure PVC resin is highly brittle, has poor processing performance and impact resistance, a low heat distortion temperature (Vicat softening point is only about 85℃), and poor thermal stability. These shortcomings limit the improvement of PVC material performance, causing PVC to fail to meet the special requirements of some technical fields.

[0003] Most domestic manufacturers improve the processability and flowability of PVC products by adding plasticizers such as DOP and DBP, but this causes the Vicat temperature of the PVC to drop rapidly. Many modifiers have also been developed domestically to improve the heat resistance, Vicat temperature, or heat distortion temperature of PVC products. However, most of these technologies modify PVC by adding monomers such as α-methylstyrene, methacrylonitrile, or NPMI. While the introduction of monomers can improve the thermal stability of PVC, it also leads to problems such as yellowing and processing difficulties. Many heat-resistant modifiers from abroad have also entered the Chinese market, such as Kanekachi TELALLOY A15 and TELALLOY A50B from Japan. Both are ABS-based heat-resistant modifiers that show good compatibility with PVC and can improve the temperature resistance of products, but their improvement on the impact resistance of PVC is not ideal.

[0004] Chinese patent CN106336478B discloses a method for preparing a PVC resin modifier, which improves the processing fluidity, Vicat temperature, and surface finish of PVC products by synthesizing a copolymer of styrene-acrylonitrile-acrylate and methyl methacrylate. Chinese patent CN104194210B discloses a PVC composite modifier and its preparation method, whose modifier includes diisononyl adipate, di(2-ethylhexyl) phthalate, tri(2-ethylhexyl) trimellitate, antioxidants, nucleating agents, and other components, which improve the impact strength of PVC products through the combined effect of the components. However, the modifiers in the above patents still have considerable room for improvement in the processing performance, Vicat temperature, and impact strength of PVC products, and cannot solve the problem of yellowing during PVC processing. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention first provides a heat-resistant modifier for PVC materials; by weight, the raw materials for preparing the modifier include: 3-22 parts of organosilicon molecules, 70-150 parts of reactive monomers, 0.1-2 parts of molecular weight regulator, 0.5-4 parts of emulsifier, and 0.05-1 parts of initiator.

[0006] Furthermore, the organosilicon molecule has the following structure:

[0007]

[0008] Wherein, R1 is selected from any one of C1-C30 alkyl, C1-C30 substituted alkyl, and C1-C30 acyl; R2, R3, R4, and R5 are independently selected from at least one of -H, -OH, -F, C1-C30 alkyl, C1-C30 alkenyl, phenyl, substituted phenyl, C1-C30 alkoxy, C1-C30 acyl, and C1-C30 acyloxy; n is an integer from 0 to 50; and X is a substituent group having at least one alkenyl group.

[0009] The double bonds in organosilicon molecules are used for copolymerization with reactive monomers. The alkoxy groups attached to the silicon atoms can form siloxane bonds with the hydroxyl groups on the filler surface under certain conditions and remove methanol. They can also form chemical bonds with PVC and remove methyl chloride. All of these can improve the thermal stability, Vicat temperature, and impact resistance of PVC products. However, the chain length and number of branches of organosilicon molecules will affect the molecular structure of the modifiers that are finally prepared, further affecting the bonding between the modifiers and fillers, PVC, and crosslinking with PVC, leading to differences in the performance of the final modified PVC products. Only organosilicon molecules of suitable types and chain lengths can form modifiers with excellent performance and the modified PVC products they produce.

[0010] Further, R1 is selected from any one of C1-C15 alkyl, C1-C15 substituted alkyl, and C1-C15 acyl. More preferably, it is a C1-C15 alkyl.

[0011] Furthermore, the C1-C15 alkyl groups include, but are not limited to, at least one of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, cyclooctyl, nonyl, decyl, n-undecyl, isoundecyl, dodecyl, and 1,3-dimethylundecyl.

[0012] Furthermore, the substituent groups in the C1-C15 substituted alkyl groups include, but are not limited to, at least one of -F, -Cl, -Br, -NH2, -NH-, hydroxyl, carbonyl, mercapto, ether, ester, and amide groups.

[0013] Furthermore, the acyl group of the C1-C15 includes, but is not limited to, at least one of acetyl, propionyl, butyryl, and hexanoyl.

[0014] In one embodiment, R1 is a C1-C8 alkyl group, more preferably any one of methyl, ethyl, propyl, isopropyl, and butyl.

[0015] Furthermore, R2, R3, R4 and R5 are independently selected from at least one of -H, C1-C18 alkyl, phenyl, substituted phenyl, C1-C18 alkoxy, and C1-C18 acyloxy.

[0016] Furthermore, R2, R3, R4 and R5 are independently preferably any one or a combination of several of -H, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, phenyl, methylphenyl, dimethylphenyl, benzyl, 4-chlorophenyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, propionyloxy, acetoxy, and hexanoyloxy; n is preferably an integer from 0 to 10.

[0017] Further, the substituent group in X that has at least one alkenyl group includes, but is not limited to, at least one of alkenyl, alkenyl-substituted alkyl, alkenyl-substituted acyloxy, alkenyl-substituted alkoxy, alkenyl-substituted phenyl, and alkenyl-substituted tertiary amine. Preferably, it is any one of alkenyl, alkenyl-substituted alkyl, and alkenyl-substituted acyloxy.

[0018] Furthermore, the substituent group in X that has at least one alkenyl group is preferably selected from any one of vinyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, allyl, allyl, allenyl, allepenyl, butadienyl, methacryloyloxy, methacryloyloxymethyl, methacryloyloxyethyl, methacryloyloxypropyl, and methacryloyloxyisopropyl.

[0019] In one embodiment, when R1 is a C1-C8 alkyl group, and particularly preferably any one of methyl, ethyl, propyl, isopropyl, and butyl, R2, R3, R4, and R5 are independently preferably at least one of C1-C10 alkyl or C1-C10 alkoxy groups, and X is selected from any one of vinyl, propenyl, butenyl, pentenyl, allyl, allyl, allenyl, butadienyl, methacryloyloxy, methacryloyloxymethyl, methacryloyloxyethyl, methacryloyloxypropyl, and methacryloyloxyisopropyl.

[0020] In a preferred embodiment, when R1 is any one of methyl, ethyl, propyl, isopropyl, and butyl, R2 and R3 are independently selected from any one of methyl, ethyl, and propyl, R4 and R5 are independently selected from any one of methoxy, ethoxy, propoxy, and butoxy, X is selected from any one of vinyl, propenyl, methacryloyloxymethyl, methacryloyloxyethyl, and methacryloyloxypropyl, and n is 0-6.

[0021] In a more preferred embodiment, X is any one of vinyl, propylene, or methacryloyloxypropyl, and n is 0-4.

[0022] Preferably, the raw materials for preparing the heat-resistant modifier, by weight, include: 3-15 parts of organosilicon molecules, 80-120 parts of reactive monomers, 0.2-1 parts of molecular weight regulator, 1-4 parts of emulsifier, and 0.1-0.5 parts of initiator.

[0023] Furthermore, the amount of the organosilicon molecules accounts for 4-12% of the total weight of the organosilicon molecules and reactive monomers.

[0024] Furthermore, the reaction monomer is selected from at least one of styrene and its derivatives, acrylonitrile and its derivatives, acrylic acids, acrylates, N-phenylmaleimide, and maleic anhydride.

[0025] Furthermore, the styrene and its derivatives may be selected from at least one of styrene, α-methylstyrene, ethylstyrene, N,N-dimethylaminostyrene, N,N-diethylaminostyrene, and N,N-diphenylaminostyrene; preferably styrene or α-methylstyrene.

[0026] Furthermore, the acrylonitrile and its derivatives may be selected from at least one of acrylonitrile, methacrylonitrile, and ethyl acrylonitrile.

[0027] Furthermore, the acrylates include, but are not limited to, at least one of methacrylates, phenyl methacrylates, and (meth)acrylate-2-hydroxyalkyl esters.

[0028] Preferably, the acrylate is any one of methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, and 2-hydroxyethyl methacrylate. More preferably, it is any one of methyl methacrylate, ethyl methacrylate, and 2-hydroxypropyl methacrylate.

[0029] Preferably, the reactive monomers include styrene and its derivatives, acrylonitrile and its derivatives, acrylates, and N-phenylmaleimide.

[0030] In a preferred embodiment, the reactive monomers include α-methylstyrene, methyl methacrylate, acrylonitrile, and N-phenylmaleimide. In this application, the reactive monomers serve as the main modifier components. α-methylstyrene is used to increase the heat resistance (Tg) of the heat-resistant modifier; however, its heat resistance is insufficient, and it easily decomposes at high temperatures, so its usage should not be excessive. Acrylonitrile can increase the intermolecular forces of the modifier. N-phenylmaleimide combines the effects of both, is more stable and has better heat resistance than α-methylstyrene, but its effect on increasing the intermolecular forces of the modifier is limited. Therefore, its main function remains to increase the Tg of the modifier. However, its solubility in α-methylstyrene and mixed solutions of methyl methacrylate and acrylonitrile is low, and its melting point is high, requiring sophisticated equipment. Therefore, it cannot be used in large quantities in this emulsion polymerization method. Only by maintaining the content of the four monomers within a suitable range can they produce the best effect with organosilicon molecules, giving the modified PVC products the best thermal stability, impact strength, and processing performance.

[0031] Preferably, the weight ratio of α-methylstyrene, methyl methacrylate, acrylonitrile, and N-phenylmaleimide is (20-30):(20-50):(20-30):(10-18).

[0032] In a preferred embodiment, the weight ratio of α-methylstyrene, methyl methacrylate, acrylonitrile, and N-phenylmaleimide is 25:25:35:15.

[0033] Furthermore, the molecular weight regulator is selected from at least one of tert-dodecyl mercaptan, n-dodecyl mercaptan, and α-methylstyrene linear dimer. Preferably, it is α-methylstyrene linear dimer.

[0034] Furthermore, the amount of the emulsifier is 0.8-3% of the total weight of the organosilicon molecules and reactive monomers.

[0035] Furthermore, the emulsifier includes reactive and non-reactive emulsifiers in a weight ratio of (0.5-2):(2-5). The emulsifier in this application provides stability to the emulsion during synthesis and storage / transportation, and also plays a crucial role in the thermal stability and processability of the heat-resistant modifier. After synthesis, the emulsifier remains in the modifier. The non-reactive emulsifier, existing as a small molecule, migrates to the material surface during PVC product processing, acting as an external lubricant. The reactive emulsifier remains on the surface of the heat-resistant modifier, and, having a similar polarity to PVC, acts as an internal lubricant. Therefore, the combined use of both achieves the best effect.

[0036] Furthermore, the reactive emulsifier is selected from at least one of allyl sulfonate, acrylamide sulfonate, maleic anhydride derivative, and allyl succinate alkyl ester sulfonate.

[0037] Preferably, the reactive emulsifier is alkylphenol polyoxyethylene ether allyl sulfonate.

[0038] Furthermore, the non-reactive emulsifier is selected from at least one of alkyl sulfates, alkyl sulfonates, and alkylbenzene sulfonates.

[0039] Preferably, the non-reactive emulsifier is an alkylbenzene sulfonate, specifically a C8-C18 alkyl sulfonate.

[0040] Furthermore, the amount of the initiator is 0.1-0.5% of the total weight of the organosilicon molecules and reactive monomers.

[0041] Furthermore, the initiator is selected from at least one of tert-butyl hydroperoxide, azobisisobutyronitrile, azobisisoheptanenitrile, potassium persulfate, and ammonium persulfate.

[0042] In a more preferred embodiment, the raw materials for preparing the heat-resistant modifier include: 6.4 parts of organosilicon molecules, 93.6 parts of reactive monomers, 0.47 parts of molecular weight regulator, 2 parts of emulsifier, and 0.25 parts of initiator.

[0043] Furthermore, the raw materials for preparing the heat-resistant modifier also include 100-200 parts of solvent, which is selected from one or a combination of several of water, ethyl acetate, formic acid, methanol, ethanol, propanol, isopropanol, and ethyl formate.

[0044] Secondly, the present invention also provides a method for preparing the heat-resistant modifier for PVC materials, comprising the following steps:

[0045] S1. Add solvent to reactor and heat to 60-80℃. Add emulsifier, organosilicon molecules, reactants, molecular weight regulators and initiators while stirring. Start the reaction. After the temperature rises to 70-105℃, cool down and discharge the material.

[0046] S2. The material in S1 is spray-dried at a low temperature under vacuum, below 55°C, to obtain a powdered modifier.

[0047] Furthermore, the preparation method specifically includes:

[0048] S1. Add solvent to the reactor and heat to 60-80℃. Add emulsifier accounting for 1 / 3-1 / 2 of its total weight and stir. Then add organosilicon molecules accounting for 1 / 3-3 / 4 of its total weight, reactant accounting for 1 / 4-1 / 2 of its total weight, and molecular weight regulator accounting for 1 / 4-1 / 2 of its total weight and stir. Then add initiator accounting for 1 / 3-3 / 4 of its total weight and start the reaction. After the temperature rises to 70-105℃, start the cooling process and cool down to 60-80℃.

[0049] S2. After cooling down, add the remaining organosilicon molecules, the reaction monomer accounting for 1 / 4 to 1 / 2 of its total weight, and the molecular weight regulator accounting for 1 / 4 to 1 / 2 of its total weight to S1 and stir the reaction. After the reaction temperature is raised to 70-105℃, it is cooled down to 60-80℃ again.

[0050] S3. After cooling down, add the remaining emulsifier to S2 and stir. Then add the remaining reactive monomer and molecular weight regulator, stir, and add the initiator accounting for 1 / 5-1 / 4 of the total weight to start the reaction. After the reaction temperature is raised to 70-105℃, keep it at the temperature for a period of time, then add the remaining initiator and keep it at the temperature for 1-3 hours before cooling down and discharging.

[0051] S4. The material in S3 is spray-dried at a low temperature under vacuum, below 55°C, to obtain a powdered heat-resistant modifier.

[0052] Furthermore, the particle size of the heat-resistant modifier is less than or equal to 30 mesh.

[0053] Furthermore, the heat-resistant modifier described in this invention can be used to modify PVC materials and in the production and manufacturing process of PVC products.

[0054] Furthermore, the amount of the heat-resistant modifier used is 5-40 wt% of the PVC resin, preferably 10-30 wt%.

[0055] Beneficial effects

[0056] 1. This application introduces appropriate types and amounts of organosilicon monomers, which increase the interaction and cross-linking state between the modifier, PVC and PVC product fillers through the cross-linking properties of organosilicon monomers. This results in a significant increase in the Vicat temperature of PVC products. At the same time, the cross-linking force between the organosilicon molecular chain segments in the modifier and the fillers enhances the impact resistance of PVC products.

[0057] 2. This application optimizes the different types and amounts of reactive monomers. By combining reactive monomers, not only are the glass transition temperatures of modifiers and PVC products increased, but the processing performance of PVC products is also improved, avoiding problems such as sticking and product color difference.

[0058] 3. Compared with excellent foreign modifier products, through the combined effect of each component, the modifier of this application still significantly improves the glass transition temperature, impact strength and processing performance of PVC products when added in small amounts. It can reduce the amount of modifier used in PVC products and greatly reduce production costs. In addition, the heat-resistant modifier of this application can improve the plasticizing speed of PVC. Under the same plasticizing speed, the processing temperature can be reduced by 5-10℃, which also plays a role in energy saving and environmental protection. Detailed Implementation

[0059] Example

[0060] Example 1

[0061] The first aspect of this embodiment provides a heat-resistant modifier for PVC materials; by weight, the raw materials for preparing the heat-resistant modifier include: 6.4 parts of organosilicon molecules, 93.6 parts of reactive monomers, 0.47 parts of molecular weight regulator, 2 parts of emulsifier, 0.25 parts of initiator, and 150 parts of water.

[0062] The organosilicon molecule is vinyltrimethoxysilane; the reactant monomers are α-methylstyrene, methyl methacrylate, acrylonitrile, and N-phenylmaleimide in a weight ratio of 25:25:35:15; the molecular weight regulator is α-methylstyrene linear dimer; the emulsifiers are alkylphenol polyoxyethylene ether allyl sulfonate (SR10) and sodium dodecylbenzenesulfonate in a weight ratio of 1:3; and the initiator is potassium persulfate.

[0063] The second aspect of this embodiment provides a method for preparing the heat-resistant modifier specifically for PVC materials:

[0064] S1. Add 150 parts of water to the reactor and heat to 70°C. Add 1 / 2 of the total weight of emulsifier and stir. Then add 1 / 2 of the total weight of organosilicon molecules, 1 / 3 of the total weight of reaction monomers, and 1 / 3 of the total weight of molecular weight regulators and stir. Then add 1 / 2 of the total weight of initiator and start the reaction. After the temperature rises to 90°C, start the cooling process and cool down to 70°C.

[0065] S2. After cooling, add the remaining organosilicon molecules, 1 / 3 of the total weight of the reactant monomer, and 1 / 3 of the total weight of the molecular weight regulator to S1 and stir the reaction. The reaction temperature is raised to 90°C and then cooled to 70°C.

[0066] S3. After cooling down, add the remaining emulsifier to S2 and stir. Then add the remaining reactive monomer and molecular weight regulator, stir, and add an initiator accounting for 1 / 4 of its total weight to start the reaction. After the reaction temperature is raised to 90℃, keep it at that temperature for a period of time, then add the remaining initiator and keep it at that temperature for 1 hour before cooling down and discharging.

[0067] S4. The material in S3 is subjected to low-temperature vacuum spray drying at a temperature of 55°C to obtain a powdered modifier.

[0068] Example 2

[0069] The first aspect of this embodiment provides a heat-resistant modifier for PVC materials; by weight, the raw materials for preparing the modifier include: 3 parts of organosilicon molecules, 80 parts of reactive monomers, 0.2 parts of molecular weight regulator, 1 part of emulsifier, 0.1 parts of initiator, and 100 parts of water.

[0070] The organosilicon molecule is vinyltriethoxysilane; the reactant monomers are α-methylstyrene, methyl methacrylate, acrylonitrile, and N-phenylmaleimide in a weight ratio of 20:20:30:18; the molecular weight regulator is α-methylstyrene linear dimer; the emulsifiers are alkylphenol polyoxyethylene ether allyl sulfonate (SR10) and sodium dodecylbenzenesulfonate in a weight ratio of 1:2; and the initiator is potassium persulfate.

[0071] The second aspect of this embodiment provides a method for preparing the heat-resistant modifier specifically for PVC materials:

[0072] S1. Add 100 parts of water to the reactor and heat to 60°C. Add 1 / 3 of the total weight of emulsifier and stir. Then add 1 / 3 of the total weight of organosilicon molecules, 1 / 4 of the total weight of reaction monomers, and 1 / 4 of the total weight of molecular weight regulators and stir. Then add 1 / 3 of the total weight of initiator and start the reaction. After the temperature rises to 70°C, start the cooling process and cool down to 60°C.

[0073] S2. After cooling down, add the remaining organosilicon molecules, 1 / 4 of the total weight of the reaction monomer, and 1 / 4 of the total weight of the molecular weight regulator to S1 and stir the reaction. The reaction temperature is raised to 70°C and then cooled down to 60°C.

[0074] S3. After cooling down, add the remaining emulsifier to S2 and stir. Then add the remaining reactive monomer and molecular weight regulator, stir, and add an initiator accounting for 1 / 4 of the total weight to start the reaction. After the reaction temperature is raised to 70℃, keep it at that temperature for a period of time, then add the remaining initiator and keep it at that temperature for 3 hours before cooling down and discharging.

[0075] S4. The material in S3 is subjected to low-temperature vacuum spray drying at a temperature of 55°C to obtain a powdered modifier.

[0076] Example 3

[0077] The first aspect of this embodiment provides a heat-resistant modifier for PVC materials; by weight, the raw materials for preparing the modifier include: 15 parts of organosilicon molecules, 120 parts of reactive monomers, 1 part of molecular weight regulator, 4 parts of emulsifier, 0.5 parts of initiator, and 200 parts of water.

[0078] The organosilicon molecule is γ-methacryloyloxypropyltrimethoxysilane; the reactant monomers are α-methylstyrene, methyl methacrylate, acrylonitrile, and N-phenylmaleimide in a weight ratio of 30:50:20:10; the molecular weight regulator is α-methylstyrene linear dimer; the emulsifiers are alkylphenol polyoxyethylene ether allyl sulfonate (SR10) and sodium dodecylbenzenesulfonate in a weight ratio of 2:5; and the initiator is potassium persulfate.

[0079] The second aspect of this embodiment provides a method for preparing the heat-resistant modifier specifically for PVC materials:

[0080] S1. Add 200 parts of water to the reactor and heat to 80°C. Add 1 / 2 of the total weight of emulsifier and stir. Then add 1 / 2 of the total weight of organosilicon molecules, 1 / 2 of the total weight of reaction monomers, and 1 / 2 of the total weight of molecular weight regulator and stir. Then add 1 / 3 of the total weight of initiator and start the reaction. After the temperature rises to 105°C, start the cooling process and cool down to 80°C.

[0081] S2. After cooling down, add the remaining organosilicon molecules, 1 / 4 of the total weight of the reaction monomer, and 1 / 4 of the total weight of the molecular weight regulator to S1 and stir the reaction. The reaction temperature is raised to 105℃ and then cooled down to 80℃.

[0082] S3. After cooling down, add the remaining emulsifier to S2 and stir. Then add the remaining reactive monomer and molecular weight regulator, stir, and add an initiator accounting for 1 / 4 of its total weight to start the reaction. After the reaction temperature is raised to 105℃, keep it at the temperature for a period of time, then add the remaining initiator and keep it at the temperature for 1 hour before cooling down and discharging.

[0083] S4. The material in S3 is subjected to low-temperature vacuum spray drying at a temperature of 50°C to obtain a powdered modifier.

[0084] Example 4

[0085] It is basically the same as Example 1, except that the organosilicon molecule is methacryloyloxytrimethoxysilane.

[0086] Comparative Example 1

[0087] The preparation of the modifier is basically the same as in Example 1, except that, by weight, the raw materials for the preparation of the modifier include: 100 parts of reactive monomer, 0.47 parts of molecular weight regulator, 2 parts of emulsifier, 0.25 parts of initiator, and 150 parts of water.

[0088] Comparative Example 2

[0089] It is basically the same as Example 1, except that the weight ratio of α-methylstyrene, methyl methacrylate, acrylonitrile and N-phenylmaleimide is 55:15:15:15.

[0090] Comparative Example 3

[0091] It is basically the same as Example 1, except that the weight ratio of α-methylstyrene, methyl methacrylate, acrylonitrile and N-phenylmaleimide is 25:25:30:20.

[0092] Comparative Example 4

[0093] It is basically the same as Example 1, except that the emulsifier is alkylphenol polyoxyethylene ether allyl sulfonate (SR10) and sodium dodecylbenzene sulfonate, with a weight ratio of 2:1.

[0094] Comparative Example 5

[0095] The process is basically the same as in Example 1, except that, by weight, the raw materials for preparing the heat-resistant modifier include: 35 parts of organosilicon molecules, 65 parts of reactive monomers, 0.47 parts of molecular weight regulator, 2 parts of emulsifier, 0.25 parts of initiator, and 150 parts of water.

[0096] Performance testing methods:

[0097] The modifiers prepared in the examples and comparative examples, as well as commercially available foreign modifiers (competitor 1, competitor 2, and competitor 3), were formulated into PVC products according to the formula. The Vicat temperature (GB / T 1633-2000), impact strength (GB / T1043.1-2008), and processing performance (visual inspection) of the products were measured and compared.

[0098] The PVC product formulation is as follows: by weight, 100 parts PVC resin (SG-7), 3 parts stabilizer (TM-181), 1 part internal lubricant (AG-70S), 1 part external lubricant (W-14), 8 parts titanium dioxide (TLA-120), 1 part processing aid (K-175), 8 parts impact toughening agent (MBS M-48), and 20 parts heat-resistant modifier.

[0099] Performance test results:

[0100] The test results are shown in Table 1.

[0101] Table 1

[0102]

[0103]

[0104] Conclusions: Examples 1-3 of this invention all exhibited excellent thermal stability, processing performance, and mechanical properties. In Comparative Example 1, the absence of added organosilicon molecules significantly affected the Vicat temperature and impact strength of the product; however, excessive organosilicon also negatively impacted these properties. In Comparative Example 2, excessive α-methylstyrene, while increasing the Vicat temperature, resulted in a stronger odor and yellowing during processing, leading to poorer application performance. In Comparative Example 3, excessive N-phenylmaleimide increased the risk factors during synthesis and also affected plasticizing time, limiting its use as a heat-resistant modifier for PVC. Comparative Example 4 demonstrated that only at appropriate concentrations could the synergistic effect of the two different types of emulsifiers be achieved, improving the product's processing performance. Comparison with foreign products (competitors 1-3) proved that the heat resistance temperature of this patent has reached the same level and has a significant advantage in improving impact strength, making it suitable for industrial production.

Claims

1. A heat-resistant modifier specifically for PVC materials, characterized in that, The raw materials for preparing the modifier, by weight, include: 3-15 parts of organosilicon molecules, 80-120 parts of reactive monomers, 0.2-1 parts of molecular weight regulator, 1-4 parts of emulsifier, and 0.1-0.5 parts of initiator. The organosilicon molecule has the following structure: ； Wherein, R1 is a C1-C8 alkyl group, and R2, R3, R4, and R5 are independently any one or a combination of several of -H, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, phenyl, methylphenyl, dimethylphenyl, benzyl, 4-chlorophenyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, propionyloxy, acetoxy, and hexanoyloxy; when R1 is any one of methyl, ethyl, propyl, isopropyl, and butyl, R2 and R3 are independently selected from any one of methyl, ethyl, and propyl, and R4 and R5 are independently selected from any one of methoxy, ethoxy, propoxy, and butoxy; X is selected from any one of vinyl, propenyl, methacryloyloxymethyl, methacryloyloxyethyl, and methacryloyloxypropyl, and n is 0-6; The reactive monomers include α-methylstyrene, methyl methacrylate, acrylonitrile, and N-phenylmaleimide; the weight ratio of α-methylstyrene, methyl methacrylate, acrylonitrile, and N-phenylmaleimide is (20~30):(20~50):(20~30):(10~18). The emulsifier includes a reactive emulsifier and a non-reactive emulsifier, with a weight ratio of (0.5-2):(2-5); the reactive emulsifier is alkylphenol polyoxyethylene ether allyl sulfonate; the non-reactive emulsifier is a C8-C18 alkyl sulfonate.

2. A method for preparing the heat-resistant modifier according to claim 1, characterized in that, Includes the following steps: S1. Add solvent to reactor and heat to 60-80℃. Add emulsifier, organosilicon molecules, reactants, molecular weight regulators and initiators while stirring. Start the reaction. After the temperature rises to 70-105℃, cool down and discharge the material. S2. The material in S1 is spray-dried at a low temperature under vacuum, below 55°C, to obtain a powdered modifier.

3. The preparation method according to claim 2, characterized in that, Specifically: S1. Add solvent to the reactor and heat to 60-80℃. Add emulsifier accounting for 1 / 3-1 / 2 of its total weight and stir. Then add organosilicon molecules accounting for 1 / 3-3 / 4 of its total weight, reactant accounting for 1 / 4-1 / 2 of its total weight, and molecular weight regulator accounting for 1 / 4-1 / 2 of its total weight and stir. Then add initiator accounting for 1 / 3-3 / 4 of its total weight and start the reaction. After the temperature rises to 70-105℃, start the cooling process and cool down to 60-80℃. S2. After cooling down, add the remaining organosilicon molecules, the reaction monomer accounting for 1 / 4 to 1 / 2 of its total weight, and the molecular weight regulator accounting for 1 / 4 to 1 / 2 of its total weight to S1 and stir the reaction. After the reaction temperature is raised to 70-105℃, it is cooled down to 60-80℃ again. S3. After cooling down, add the remaining emulsifier to S2 and stir. Then add the remaining reactive monomer and molecular weight regulator, stir, and add the initiator accounting for 1 / 5-1 / 4 of the total weight to start the reaction. After the reaction temperature is raised to 70-105℃, keep it at the temperature for a period of time, then add the remaining initiator and keep it at the temperature for 1-3 hours before cooling down and discharging. S4. The material in S3 is spray-dried at a low temperature and vacuum below 55°C to obtain a powdered heat-resistant modifier.

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