Modified impact-resistant ACR for polyvinyl chloride and preparation method of modified impact-resistant ACR

Abstract

The invention discloses modified impact-resistant ACR for polyvinyl chloride and a preparation method of the modified impact-resistant ACR, and relates to the field of impact-resistant modifiers. The modified impact-resistant ACR is prepared from the following raw materials: methyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, glycidyl methacrylate, acrylamide, divinyl benzene, maleic anhydride grafted nitrile rubber, methacrylic acid, an initiator, an emulsifier and a catalyst; the maleic anhydride grafted nitrile rubber is obtained by graft polymerization of maleic anhydride and nitrile rubber; the emulsifier is obtained by mixing lauryl sodium sulfate and nonylphenol polyoxyethylene ether. The preparation method of the modified impact-resistant ACR comprises the following steps: preparing maleic anhydride grafted nitrile rubber, preparing a pre-emulsion, carrying out emulsion polymerization, and preparing the modified impact-resistant ACR. The modified impact-resistant ACR prepared by the invention can effectively enhance the low-temperature notch impact strength and ultraviolet aging resistance of polyvinyl chloride.

Description

Technical Field

[0001] This invention relates to the field of impact modifiers, specifically to a modified impact-resistant ACR for polyvinyl chloride and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC), as a general-purpose plastic with large production volume and high cost performance, is widely used in building pipes, home appliance housings, decorative materials, automotive interiors and other fields. However, the presence of a large number of chlorine atoms in its molecular chain structure leads to a weakening of the molecular chain mobility at low temperatures, making it prone to brittle fracture and a significant decrease in notched impact strength. At the same time, under outdoor or ultraviolet light irradiation, PVC molecular chains are prone to photo-oxidative degradation, manifested as surface yellowing, cracking and mechanical property degradation, which seriously limits its application expansion in low-temperature environments and outdoor scenarios.

[0003] To improve the impact resistance of PVC, the industry commonly employs the addition of impact modifiers. Among these, acrylate copolymers (ACRs) have become a mainstream impact modifier due to their good compatibility with the PVC matrix, improved processing fluidity, and lack of impact on product transparency. However, existing conventional ACRs, under low-temperature conditions, have limited effectiveness in absorbing impact energy in their elastomer phase, thus limiting their improvement on the low-temperature notched impact strength of PVC. Prior art (CN118955956B) discloses a high-impact modifier for polyvinyl chloride and its preparation method. This prior art mainly focuses on low-temperature impact resistance and impact retention after rapid heating, but it is prone to mechanical property degradation under outdoor UV conditions, failing to meet weather resistance requirements, and its basic mechanical property stability is insufficient at low temperatures. Prior art (CN120289728A) discloses an acrylate additive for PVC and its preparation method. While this prior art can enhance UV aging resistance, it lacks synergy between low-temperature impact resistance and UV resistance, failing to meet users' needs for multi-performance synergistic improvement.

[0004] In summary, although the existing technical solutions have improved the impact modifiers for polyvinyl chloride to some extent, the following technical problems still exist: they cannot effectively enhance the low-temperature notched impact strength and UV aging resistance of polyvinyl chloride. Summary of the Invention

[0005] In order to solve the above-mentioned problems in the prior art, the present invention provides a modified impact-resistant ACR for polyvinyl chloride and its preparation method, and achieves the following objective: to prepare a modified impact-resistant ACR that can effectively enhance the low-temperature notched impact strength and UV aging resistance of polyvinyl chloride.

[0006] To achieve the above objectives, the following technical solution is adopted: A modified impact-resistant ACR for polyvinyl chloride, by weight, comprises the following raw materials: 50-60 parts methyl methacrylate, 30-40 parts butyl acrylate, 10-15 parts isooctyl acrylate, 2-5 parts glycidyl methacrylate, 1-3 parts acrylamide, 0.5-1.5 parts divinylbenzene, 5-8 parts maleic anhydride-grafted nitrile rubber, 1-2 parts methacrylic acid, 0.3-0.8 parts initiator, 2-3 parts emulsifier, and 0.8-1 parts catalyst.

[0007] The maleic anhydride-grafted nitrile rubber is obtained by grafting and polymerizing maleic anhydride and nitrile rubber.

[0008] The initiator is ammonium persulfate (APS).

[0009] The emulsifier is obtained by mixing sodium dodecyl sulfate and nonylphenol polyoxyethylene ether, with a mass ratio of sodium dodecyl sulfate to nonylphenol polyoxyethylene ether of 1:1.5.

[0010] The catalyst is triethylamine.

[0011] This invention also provides a method for preparing modified impact-resistant ACR for polyvinyl chloride, comprising the following steps: Step 1: Preparation of maleic anhydride-grafted nitrile rubber Acrylonitrile rubber (NBR) was added to toluene at a mass ratio of 1:(5-8.5). Under nitrogen protection, the mixture was heated to 70-80°C and stirred for 1-2 hours at 200-300 rpm. Then, the temperature was raised to 90-100°C, and maleic anhydride (3-5% of the NBR mass) was added, along with an initiator (1-1.5% of the NBR mass). The reaction was continued under nitrogen atmosphere with stirring for 4-6 hours. After the reaction was complete, the mixture was poured into excess anhydrous ethanol to precipitate the solid. The precipitate was filtered after complete precipitation, and the solid product was collected. The solid product was washed 3-5 times with anhydrous ethanol and then dried at 80-90°C to constant weight to obtain maleic anhydride-grafted NBR. The initiator was benzoyl peroxide.

[0012] Step 2: Preparation of Pre-emulsion Maleic anhydride-grafted nitrile rubber was dissolved in ethyl acetate at a mass ratio of 1:(1-2) to obtain a rubber solution.

[0013] Sodium dodecyl sulfate and nonylphenol polyoxyethylene ether were mixed evenly at a mass ratio of 1:1.5 to obtain an emulsifier.

[0014] Dissolve the emulsifier in deionized water at a mass ratio of (3-4):100. Turn on the stirrer at 300-500 rpm until completely dissolved.

[0015] Add butyl acrylate, isooctyl acrylate, rubber solution, glycidyl methacrylate, acrylamide, divinylbenzene, methacrylic acid, and methyl methacrylate in sequence. Heat to 30-40℃ and stir for 30-60 minutes at a speed of 800-1200 rpm to obtain a pre-emulsion.

[0016] Step 3: Emulsion Polymerization Dissolve the initiator in deionized water to prepare an initiator aqueous solution with a mass fraction of 5-10%; divide the initiator aqueous solution into two portions, with the volume ratio of the first portion to the second portion being 1:2.

[0017] Divide the pre-emulsion into two portions, with the volume ratio of the first portion to the second portion being 1:4.

[0018] Mix the first pre-emulsion with deionized water at a mass ratio of 1:(1.4-1.6). Start stirring at 200-300 rpm and purge with nitrogen for 30 minutes. Heat to 70-75℃ and add the first initiator aqueous solution, continuing to stir and maintain the temperature for 30-60 minutes. While maintaining the reaction temperature at 70-75℃, simultaneously add the second pre-emulsion and the second initiator aqueous solution dropwise over 2-4 hours. After the addition is complete, add the catalyst and heat to 85-90℃ for curing, stirring and maintaining the temperature for 1-2 hours to obtain the ACR emulsion.

[0019] Step 4: Prepare modified impact-resistant ACR Cool the ACR emulsion to 40-50℃, add ammonia dropwise to the reaction system to adjust the pH to 6-7; then add a demulsifier, the amount of which is 10-15% of the ACR emulsion mass, and stir until the precipitate is completely formed. Filter and collect the precipitate, wash it 3-5 times with deionized water, and then vacuum dry it at 60-70℃ and a vacuum of -0.08 MPa until constant weight. Pulverize the dried precipitate and pass it through an 80-120 mesh sieve to obtain modified impact-resistant ACR.

[0020] The ammonia solution has a mass fraction of 10%; the demulsifier is a calcium chloride aqueous solution with a mass fraction of 5-10%.

[0021] In this invention, the anhydride groups of maleic anhydride-grafted nitrile rubber undergo an epoxy-anhydride ring-opening reaction with the epoxy groups of glycidyl methacrylate, forming a stable covalent ester bond. This chemical reaction anchors the nitrile rubber segments of the maleic anhydride-grafted nitrile rubber onto the ACR molecular chain, enhancing its bonding force with the matrix and preventing it from detaching due to stress during PVC processing or use, thus further improving toughening efficiency.

[0022] Butyl acrylate / isooctyl acrylate, as the main monomers of the ACR "soft core," constitutes the basic elastic matrix of ACR itself. Maleic anhydride-grafted nitrile rubber, dissolved in ethyl acetate, is added to the pre-emulsion. The nitrile rubber segments are uniformly dispersed and embedded in the basic elastic matrix of ACR, forming a "composite toughening phase": the basic elastic matrix of ACR provides basic toughness and is responsible for absorbing low-energy impacts; the nitrile rubber segments, as a high-strength elastic dispersion phase, can absorb high-energy impacts. The synergistic effect of the two allows the impact resistance of the PVC sample to cover a wider range of stresses, further improving the room temperature impact strength and showing a more significant improvement in low-temperature impact strength.

[0023] The beneficial effects of this invention are as follows: (1) The modified impact-resistant ACR for polyvinyl chloride (PVC) of this invention can effectively enhance the notched impact strength of PVC samples at low temperatures. PVC test samples prepared using the modified impact-resistant ACR as a raw material exhibit a notched impact strength of 41.5-44.7 KJ / m at -15℃. 2 The tensile strength is 57.8-59.5 MPa, and the flexural strength is 71.6-74.7 MPa.

[0024] (2) The modified impact-resistant ACR for polyvinyl chloride (PVC) of the present invention can effectively enhance the UV aging resistance of PVC samples. PVC test samples prepared using the modified impact-resistant ACR as raw material, after UV aging for 250 h, retained a notched impact strength of 94.7-96.2% at -15℃; after UV aging for 500 h, the notched impact strength retention rate at -15℃ was 89.2-90.3%. Attached Figure Description

[0025] Appendix Figure 1 This is the Fourier transform infrared spectrum of maleic anhydride-grafted nitrile butadiene rubber. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0027] Example 1: A modified impact-resistant ACR for polyvinyl chloride and its preparation method A modified impact-resistant ACR for polyvinyl chloride, by weight, comprises the following raw materials: 50 parts methyl methacrylate, 40 parts butyl acrylate, 10 parts isooctyl acrylate, 2 parts glycidyl methacrylate, 3 parts acrylamide, 1.5 parts divinylbenzene, 5 parts maleic anhydride-grafted nitrile rubber, 1 part methacrylic acid, 0.8 parts initiator, 3 parts emulsifier, and 0.8 parts catalyst.

[0028] The initiator is ammonium persulfate (APS).

[0029] The catalyst is triethylamine.

[0030] A method for preparing modified impact-resistant ACR for polyvinyl chloride includes the following steps: Step 1: Preparation of maleic anhydride-grafted nitrile rubber Acrylonitrile rubber (NBR) was added to toluene at a mass ratio of 1:5. Under nitrogen protection, the mixture was heated to 70°C and stirred for 2 hours at 200 rpm. Then, the temperature was raised to 90°C, and maleic anhydride (3% of the NBR mass) was added, along with an initiator (1% of the NBR mass). The reaction was continued under nitrogen atmosphere for 6 hours. After the reaction was complete, the mixture was poured into excess anhydrous ethanol to precipitate the solid. The precipitate was filtered after complete precipitation, and the solid product was collected. The solid product was washed three times with anhydrous ethanol and then dried at 80°C to constant weight to obtain maleic anhydride-grafted NBR. The acrylonitrile content of the NBR was 25-30%, and the initiator was benzoyl peroxide.

[0031] Step 2: Preparation of Pre-emulsion Maleic anhydride-grafted nitrile rubber was dissolved in ethyl acetate at a mass ratio of 1:1 to obtain a rubber solution.

[0032] Sodium dodecyl sulfate and nonylphenol polyoxyethylene ether were mixed evenly at a mass ratio of 1:1.5 to obtain an emulsifier. The emulsifier was dissolved in deionized water at a mass ratio of 3:100, and stirred at 300 rpm until completely dissolved. Butyl acrylate, isooctyl acrylate, rubber solution, glycidyl methacrylate, acrylamide, divinylbenzene, methacrylic acid, and methyl methacrylate were added sequentially. The mixture was heated to 30°C and stirred for 60 minutes at a speed of 800 rpm to obtain a pre-emulsion.

[0033] Step 3: Emulsion Polymerization Dissolve the initiator in deionized water to prepare an initiator aqueous solution with a mass fraction of 5%; divide the initiator aqueous solution into two portions, with the volume ratio of the first portion to the second portion being 1:2.

[0034] Divide the pre-emulsion into two portions, with the volume ratio of the first portion to the second portion being 1:4.

[0035] The first pre-emulsion was mixed with deionized water at a mass ratio of 1:1.4. Stirring was started at 200 rpm, and nitrogen was purged for 30 minutes. The temperature was raised to 70°C, and the first initiator aqueous solution was added. Stirring and maintaining this temperature continued for 60 minutes. While keeping the reaction temperature at 70°C, the second pre-emulsion and the second initiator aqueous solution were added dropwise over a period of 4 hours. After the addition was complete, the catalyst was added, and the temperature was raised to 85°C for curing. Stirring and maintaining this temperature for 2 hours yielded the ACR emulsion.

[0036] Step 4: Prepare modified impact-resistant ACR The ACR emulsion was cooled to 40℃, and ammonia was added dropwise to adjust the pH of the reaction system to 6. Then, a demulsifier was added at 10% of the mass of the ACR emulsion, and the mixture was stirred until the precipitate was completely formed. The precipitate was collected by filtration, washed three times with deionized water, and then vacuum dried at 60℃ and -0.08 MPa until constant weight was achieved. After pulverizing, the precipitate was passed through an 80-120 mesh sieve to obtain modified impact-resistant ACR.

[0037] The ammonia solution has a mass fraction of 10%; the demulsifier is a calcium chloride aqueous solution with a mass fraction of 5-10%.

[0038] Example 2: A modified impact-resistant ACR for polyvinyl chloride and its preparation method A modified impact-resistant ACR for polyvinyl chloride, by weight, comprises the following raw materials: 55 parts methyl methacrylate, 35 parts butyl acrylate, 13 parts isooctyl acrylate, 3 parts glycidyl methacrylate, 2 parts acrylamide, 1 part divinylbenzene, 6 parts maleic anhydride-grafted nitrile rubber, 2 parts methacrylic acid, 0.5 parts initiator, 2.5 parts emulsifier, and 0.9 parts catalyst.

[0039] The initiator is ammonium persulfate (APS).

[0040] The catalyst is triethylamine.

[0041] A method for preparing modified impact-resistant ACR for polyvinyl chloride includes the following steps: Step 1: Preparation of maleic anhydride-grafted nitrile rubber Acrylonitrile rubber (NBR) was added to toluene at a mass ratio of 1:7. Under nitrogen protection, the mixture was heated to 75°C and stirred for 1.5 hours at 300 rpm. Then, the temperature was raised to 95°C, and maleic anhydride (4% of the NBR mass) was added, along with an initiator (1.5% of the NBR mass). The reaction was continued under nitrogen atmosphere with stirring for 5 hours. After the reaction was complete, excess anhydrous ethanol was added to precipitate the product. The precipitate was filtered after complete precipitation, and the solid product was collected. The product was washed four times with anhydrous ethanol and then dried at 90°C to constant weight to obtain maleic anhydride-grafted NBR. The acrylonitrile content of the NBR was 25-30%, and the initiator was benzoyl peroxide.

[0042] Step 2: Preparation of Pre-emulsion Maleic anhydride-grafted nitrile rubber was dissolved in ethyl acetate at a mass ratio of 1:1.5 to obtain a rubber solution.

[0043] Sodium dodecyl sulfate and nonylphenol polyoxyethylene ether were mixed evenly at a mass ratio of 1:1.5 to obtain an emulsifier.

[0044] Dissolve the emulsifier in deionized water at a mass ratio of 3.5:100. Start stirring at 400 rpm until completely dissolved. Add butyl acrylate, isooctyl acrylate, rubber solution, glycidyl methacrylate, acrylamide, divinylbenzene, methacrylic acid, and methyl methacrylate sequentially. Heat to 35°C and stir for 60 minutes at 1000 rpm to obtain a pre-emulsion.

[0045] Step 3: Emulsion Polymerization Dissolve the initiator in deionized water to prepare an initiator aqueous solution with a mass fraction of 8%; divide the initiator aqueous solution into two portions, with the volume ratio of the first portion to the second portion being 1:2.

[0046] Divide the pre-emulsion into two portions, with the volume ratio of the first portion to the second portion being 1:4.

[0047] The first pre-emulsion was mixed with deionized water at a mass ratio of 1:1.5. Stirring was started at 300 rpm, and nitrogen was purged for 30 minutes. The temperature was raised to 75°C, and the first initiator aqueous solution was added. Stirring and maintaining this temperature continued for 60 minutes. While keeping the reaction temperature at 75°C, the second pre-emulsion and the second initiator aqueous solution were added dropwise over 3 hours. After the addition was complete, the catalyst was added, and the temperature was raised to 90°C for curing. Stirring and maintaining this temperature for 2 hours yielded the ACR emulsion.

[0048] Step 4: Prepare modified impact-resistant ACR The ACR emulsion was cooled to 40℃, and ammonia was added dropwise to adjust the pH of the reaction system to 7. Then, a demulsifier was added at 15% of the mass of the ACR emulsion, and the mixture was stirred until the precipitate was completely formed. The precipitate was collected by filtration, washed four times with deionized water, and then vacuum dried at 70℃ and -0.08 MPa until constant weight was achieved. After pulverizing, the precipitate was passed through an 80-120 mesh sieve to obtain modified impact-resistant ACR.

[0049] The ammonia solution has a mass fraction of 10%; the demulsifier is a calcium chloride aqueous solution with a mass fraction of 5-10%.

[0050] Example 3: A modified impact-resistant ACR for polyvinyl chloride and its preparation method A modified impact-resistant ACR for polyvinyl chloride, by weight, comprises the following raw materials: 60 parts methyl methacrylate, 30 parts butyl acrylate, 15 parts isooctyl acrylate, 5 parts glycidyl methacrylate, 1 part acrylamide, 0.5 parts divinylbenzene, 8 parts maleic anhydride-grafted nitrile rubber, 2 parts methacrylic acid, 0.3 parts initiator, 2 parts emulsifier, and 1 part catalyst.

[0051] The initiator is ammonium persulfate (APS).

[0052] The catalyst is triethylamine.

[0053] A method for preparing modified impact-resistant ACR for polyvinyl chloride includes the following steps: Step 1: Preparation of maleic anhydride-grafted nitrile rubber Acrylonitrile rubber (NBR) was added to toluene at a mass ratio of 1:8.5. Under nitrogen protection, the mixture was heated to 80°C and stirred for 1 hour at 300 rpm. Then, the temperature was raised to 100°C, and maleic anhydride (5% of the NBR mass) was added, along with an initiator (1.5% of the NBR mass). The reaction was continued under nitrogen atmosphere for 4 hours. After the reaction, excess anhydrous ethanol was added to precipitate the product. The precipitate was filtered after complete precipitation, and the solid product was collected. The product was washed five times with anhydrous ethanol and then dried at 90°C to constant weight to obtain maleic anhydride-grafted NBR. The acrylonitrile content of the NBR was 25-30%, and the initiator was benzoyl peroxide.

[0054] Step 2: Preparation of Pre-emulsion Maleic anhydride-grafted nitrile rubber was dissolved in ethyl acetate at a mass ratio of 1:2 to obtain a rubber solution.

[0055] Sodium dodecyl sulfate and nonylphenol polyoxyethylene ether were mixed evenly at a mass ratio of 1:1.5 to obtain an emulsifier. The emulsifier was dissolved in deionized water at a mass ratio of 4:100, and stirred at 500 rpm until completely dissolved. Butyl acrylate, isooctyl acrylate, rubber solution, glycidyl methacrylate, acrylamide, divinylbenzene, methacrylic acid, and methyl methacrylate were added sequentially. The mixture was heated to 40°C and stirred for 30 minutes at a speed of 1200 rpm to obtain a pre-emulsion.

[0056] Step 3: Emulsion Polymerization Dissolve the initiator in deionized water to prepare an initiator aqueous solution with a mass fraction of 10%; divide the initiator aqueous solution into two portions, with the volume ratio of the first portion to the second portion being 1:2.

[0057] Divide the pre-emulsion into two portions, with the volume ratio of the first portion to the second portion being 1:4.

[0058] The first pre-emulsion was mixed with deionized water at a mass ratio of 1:1.6. Stirring was started at 300 rpm, and nitrogen was purged for 30 minutes. The temperature was raised to 75°C, and the first initiator aqueous solution was added. Stirring and maintaining this temperature continued for another 30 minutes. While maintaining the reaction temperature at 75°C, the second pre-emulsion and the second initiator aqueous solution were added dropwise over a period of 2 hours. After the addition was complete, the catalyst was added, and the temperature was raised to 90°C for curing. Stirring and maintaining this temperature for 1 hour yielded the ACR emulsion.

[0059] Step 4: Prepare modified impact-resistant ACR The ACR emulsion was cooled to 50°C, and ammonia was added dropwise to adjust the pH of the reaction system to 7. Then, a demulsifier was added at 15% of the mass of the ACR emulsion, and the mixture was stirred until the precipitate was completely formed. The precipitate was collected by filtration, washed five times with deionized water, and then vacuum dried at 70°C and -0.08 MPa until constant weight was achieved. After pulverizing, the precipitate was passed through an 80-120 mesh sieve to obtain modified impact-resistant ACR.

[0060] The ammonia solution has a mass fraction of 10%; the demulsifier is a calcium chloride aqueous solution with a mass fraction of 5-10%.

[0061] Comparative Example 1 An impact-resistant ACR for polyvinyl chloride, by weight, comprises the following raw materials: 55 parts methyl methacrylate, 35 parts butyl acrylate, 13 parts isooctyl acrylate, 3 parts glycidyl methacrylate, 2 parts acrylamide, 1 part divinylbenzene, 2 parts methacrylic acid, 0.5 parts initiator, 2.5 parts emulsifier, and 0.9 parts catalyst.

[0062] The initiator is ammonium persulfate (APS).

[0063] The catalyst is triethylamine.

[0064] A method for preparing impact-resistant ACR for polyvinyl chloride includes the following steps: Step 1: Preparation of Pre-emulsion Sodium dodecyl sulfate and nonylphenol polyoxyethylene ether were mixed evenly at a mass ratio of 1:1.5 to obtain an emulsifier.

[0065] Dissolve the emulsifier in deionized water at a mass ratio of 3.5:100. Start stirring at 400 rpm until completely dissolved. Add methyl methacrylate, butyl acrylate, isooctyl acrylate, glycidyl methacrylate, acrylamide, and divinylbenzene sequentially. Heat to 35°C and stir for 60 minutes at 1000 rpm to obtain a pre-emulsion.

[0066] Step 2: Emulsion Polymerization This step is the same as the "emulsion polymerization" step in Example 2.

[0067] Step 3: Obtaining impact-resistant ACR This step is the same as the "Preparation of Modified Impact-Resistant ACR" step in Example 2.

[0068] Comparative Example 2 An impact-resistant ACR for polyvinyl chloride, by weight, comprises the following raw materials: 55 parts methyl methacrylate, 35 parts butyl acrylate, 13 parts isooctyl acrylate, 2 parts acrylamide, 1 part divinylbenzene, 6 parts maleic anhydride-grafted nitrile rubber, 2 parts methacrylic acid, 0.5 parts initiator, 2.5 parts emulsifier, and 0.9 parts catalyst.

[0069] The initiator is ammonium persulfate (APS).

[0070] The catalyst is triethylamine.

[0071] A method for preparing impact-resistant ACR for polyvinyl chloride includes the following steps: Step 1: Preparation of maleic anhydride-grafted nitrile rubber This step is the same as the step in "Preparation of maleic anhydride-grafted nitrile rubber" in Example 2.

[0072] Step 2: Preparation of Pre-emulsion Maleic anhydride-grafted nitrile rubber was dissolved in ethyl acetate at a mass ratio of 1:1.5 to obtain a rubber solution.

[0073] Sodium dodecyl sulfate and nonylphenol polyoxyethylene ether were mixed evenly at a mass ratio of 1:1.5 to obtain an emulsifier.

[0074] Dissolve the emulsifier in deionized water at a mass ratio of 3.5:100. Start stirring at 400 rpm until completely dissolved. Add methyl methacrylate, butyl acrylate, isooctyl acrylate, acrylamide, divinylbenzene, and rubber solution sequentially. Heat to 35°C and stir for 60 minutes at 1000 rpm to obtain a pre-emulsion.

[0075] Step 3: Emulsion Polymerization This step is the same as the "emulsion polymerization" step in Example 2.

[0076] Step 4: Obtaining Impact-Resistant ACR This step is the same as the "Preparation of Modified Impact-Resistant ACR" step in Example 2.

[0077] Example 4 Performance Testing Preparation method of test samples: The raw material weight ratio is: 100 parts PVC resin, 10 parts impact-resistant ACR, 5 parts calcium-zinc stabilizer, and 2 parts lubricant; melt blending is carried out in a twin-screw extruder at a screw speed of 300 rpm and a temperature of 160-185℃. After extrusion granulation, injection molding is performed to obtain PVC test samples.

[0078] The calcium-zinc stabilizer is a polyvinyl chloride-specific composite calcium-zinc stabilizer, with a molar ratio of calcium stearate to zinc stearate of 1.5:1; the lubricant is a mixture of butyl stearate and polyethylene wax, with a mass ratio of butyl stearate to polyethylene wax of 3:2.

[0079] (a) Using the impact-resistant ACRs prepared in Examples 1-3 and Comparative Examples 1-2 as raw materials, polyvinyl chloride test samples were prepared. The notched impact strength at -15°C was tested according to the test method specified in GB / T 1043.1-2008, the tensile strength was tested according to the test method specified in GB / T 1040-2018, and the flexural strength was tested according to the test method specified in GB / T 9341-2008. Specific test results are shown in Table 1.

[0080] Table 1

[0081] As shown in Table 1, the PVC test samples prepared using the modified impact-resistant ACR prepared in Examples 1-3 as raw materials have a notched impact strength of 41.5-44.7 KJ / m at -15℃. 2The tensile strength was 57.8-59.5 MPa, and the flexural strength was 71.6-74.7 MPa. This demonstrates that the modified impact-resistant ACR prepared in this invention can effectively enhance the notched impact strength of polyvinyl chloride samples at low temperatures, while maintaining good tensile and flexural strength.

[0082] (II) The impact-resistant ACRs prepared in Examples 1-3 and Comparative Examples 1-2 were used as raw materials to prepare polyvinyl chloride (PVC) test samples. UV aging resistance tests were conducted according to the test methods specified in GB / T 16422.3-2014. UV aging resistance test method: The PVC test samples were placed in a UV aging chamber and cyclically aged for 250h and 500h. The notched impact strength retention rate (%) at -15℃ after aging was calculated. The cyclic method was: irradiation exposure at a black standard temperature of 60℃ for 8h, followed by condensation exposure at a black standard temperature of 50℃ for 4h. Specific test results are shown in Table 2.

[0083] Table 2

[0084] As shown in Table 2, the PVC test samples prepared using the modified impact-resistant ACR from Examples 1-3 as raw materials retained 94.7-96.2% of their notched impact strength at -15℃ after 250 hours of UV aging, and 89.2-90.3% after 500 hours of UV aging. This demonstrates that the modified impact-resistant ACR prepared in this invention can effectively enhance the UV aging resistance of PVC samples.

[0085] Obviously, there are many other possible implementation methods under the concept of this invention. It should be stated here that any changes made under the inventive concept of this invention will fall within the protection scope of this invention.

Claims

1. A modified impact-resistant ACR for polyvinyl chloride, characterized in that: The modified impact-resistant ACR is composed of the following raw materials: methyl methacrylate, butyl acrylate, isooctyl acrylate, glycidyl methacrylate, acrylamide, divinylbenzene, maleic anhydride-grafted nitrile rubber, methacrylic acid, initiator, emulsifier, and catalyst. The maleic anhydride-grafted nitrile rubber is obtained by grafting and polymerizing maleic anhydride and nitrile rubber. The initiator is ammonium persulfate (APS); The emulsifier is obtained by mixing sodium dodecyl sulfate and nonylphenol polyoxyethylene ether. The catalyst is triethylamine.

2. The modified impact-resistant ACR for polyvinyl chloride according to claim 1, characterized in that: The modified impact-resistant ACR has the following raw material composition by weight: 50-60 parts methyl methacrylate, 30-40 parts butyl acrylate, 10-15 parts isooctyl acrylate, 2-5 parts glycidyl methacrylate, 1-3 parts acrylamide, 0.5-1.5 parts divinylbenzene, 5-8 parts maleic anhydride-grafted nitrile rubber, 1-2 parts methacrylic acid, 0.3-0.8 parts initiator, 2-3 parts emulsifier, and 0.8-1 parts catalyst.

3. The method for preparing a modified impact-resistant ACR for polyvinyl chloride according to any one of claims 1-2, characterized in that: The process includes the steps of preparing maleic anhydride-grafted nitrile butadiene rubber, preparing a pre-emulsion, emulsion polymerization, and obtaining modified impact-resistant ACR. The preparation of maleic anhydride-grafted nitrile rubber involves: adding nitrile rubber to toluene, purging with nitrogen, heating to 70-80°C, and stirring for 1-2 hours; then heating to 90-100°C, adding maleic anhydride and initiating agent, and continuing to stir and react for 4-6 hours under a nitrogen atmosphere.

4. The method for preparing a modified impact-resistant ACR for polyvinyl chloride according to claim 3, characterized in that: The mass ratio of the nitrile rubber to toluene is 1:(5-8.5). The amount of maleic anhydride used is 3-5% of the mass of nitrile rubber.

5. The method for preparing a modified impact-resistant ACR for polyvinyl chloride according to claim 3, characterized in that: The initiating agent is benzoyl peroxide, and the amount of initiating agent used is 1-1.5% of the mass of nitrile rubber.

6. The method for preparing a modified impact-resistant ACR for polyvinyl chloride according to claim 3, characterized in that: Preparation of the pre-emulsion: Dissolve the emulsifier in deionized water, with a mass ratio of emulsifier to deionized water of (3-4):100; add butyl acrylate, isooctyl acrylate, rubber solution, glycidyl methacrylate, acrylamide, divinylbenzene, methacrylic acid, and methyl methacrylate in sequence, heat to 30-40℃, and stir for 30-60 min to obtain the pre-emulsion.

7. The method for preparing a modified impact-resistant ACR for polyvinyl chloride according to claim 6, characterized in that: The rubber solution is prepared by dissolving maleic anhydride-grafted nitrile rubber in ethyl acetate, wherein the mass ratio of maleic anhydride-grafted nitrile rubber to ethyl acetate is 1:(1-2).

8. The method for preparing a modified impact-resistant ACR for polyvinyl chloride according to claim 3, characterized in that: The emulsion polymerization reaction was carried out at a temperature of 70-75℃, and the curing temperature was 80-85℃.

9. The method for preparing a modified impact-resistant ACR for polyvinyl chloride according to claim 3, characterized in that: The modified impact-resistant ACR was prepared by cooling the ACR emulsion obtained after emulsion polymerization to 40-50℃ and adjusting the pH of the reaction system to 6-7; then adding a demulsifier and stirring until the precipitate was completely precipitated.

10. The method for preparing a modified impact-resistant ACR for polyvinyl chloride according to claim 9, characterized in that: The demulsifier is a calcium chloride aqueous solution with a mass fraction of 5-10%, and the amount of demulsifier used is 10-15% of the mass of the ACR emulsion.

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