Phosphorus-containing core-shell polymer flexibilizer as well as preparation method and application thereof

Abstract

The invention relates to the technical field of toughening modifiers, in particular to a phosphorus-containing core-shell polymer toughening agent and a preparation method and application thereof.The preparation method comprises the steps that butadiene and styrene are copolymerized to prepare a core-styrene-butadiene latex of a phosphorus-containing core-shell polymer, then the core is subjected to coating copolymerization, and phosphorus-containing nanometer core-shell polymer particles are formed; by optimizing the core-shell structure design and the introduction mode of phosphorus groups, the defect that a traditional toughening agent has negative effects on other properties while improving the toughness of a polymer is overcome. The flexibilizer not only can obviously improve the impact toughness of a polymer, but also has better thermal stability, ageing resistance and flame retardance, and is suitable for modification of various different types of polymer materials, especially engineering plastics.

Description

Technical Field

[0001] This invention relates to the field of toughening modifiers, specifically to a phosphorus-containing core-shell polymer toughening agent, its preparation method, and its application. Background Technology

[0002] To meet increasingly stringent environmental requirements, the comprehensive performance of polymer materials, especially their mechanical properties such as toughness, heat resistance, and impact resistance, has become a key consideration in the design and development of polymer materials. Traditionally, toughening agents are added to polymers to improve their mechanical properties. However, how to significantly enhance the toughness of polymers without affecting other properties (such as thermal stability and aging resistance) has always been an important issue in the field of polymer material modification.

[0003] Phosphorus, due to its unique chemical properties, has been widely used in the flame retardant and toughening applications of polymers. The introduction of phosphorus can significantly improve the impact resistance and thermal stability of polymers, while also exhibiting good aging resistance. In recent years, the application of phosphorus-containing toughening agents in polymer modification has received increasing attention.

[0004] Phosphorus-containing toughening agents typically function by introducing phosphorus groups into the polymer chain or as a component of the toughening agent. Studies have shown that the introduction of phosphorus can improve polymer toughness while simultaneously enhancing properties such as thermal stability, aging resistance, and corrosion resistance. However, the poor compatibility of traditional phosphorus-containing toughening agents with the polymer matrix limits their application in certain polymers, leading to a loss of matrix properties and restricting their use.

[0005] MBS (methacrylate-butadiene-styrene) toughening agents are widely used in engineering plastics, especially in the toughening and modification of polycarbonate (PC), polystyrene (PS), and ABS. Introducing MBS into plastics can significantly improve their impact strength, crack resistance, and low-temperature performance. With the increasing demand for high-performance plastics, the research and development of MBS toughening agents is also constantly evolving, particularly in core-shell structure design, toughening effect, compatibility, high-temperature resistance, and aging resistance. However, while commonly available MBS toughening agents impart good impact resistance to engineering plastics, they often negatively impact other properties of the material system, especially flame retardancy and thermal stability. Furthermore, the higher the concentration of MBS toughening agent, the more adversely it affects thermal stability and flame retardancy. Summary of the Invention

[0006] To overcome the shortcomings and deficiencies of existing technologies, one objective of this invention is to provide a method for preparing a phosphorus-containing core-shell polymer toughening agent. First, a phosphorus-containing core-shell polymer core—styrene-butadiene latex—is prepared by copolymerizing butadiene and styrene. Then, the core is coated and copolymerized to form phosphorus-containing nano-core-shell polymer particles. By optimizing the core-shell structure design and the introduction of phosphorus groups, this method overcomes the drawback of traditional toughening agents that negatively impact other properties while improving polymer toughness. This toughening agent not only significantly improves the impact toughness of polymers but also exhibits good thermal stability, anti-aging properties, and flame retardant properties, making it suitable for various types of polymer materials, especially for the modification of engineering plastics. This preparation method is simple to operate, easy to control, has high production efficiency, and low production cost, making it suitable for large-scale production.

[0007] A second objective of this invention is to provide a phosphorus-containing core-shell polymer toughening agent. This toughening agent not only effectively improves the toughness of polymers but also enhances their thermal stability and anti-aging properties through a rational method of introducing phosphorus groups. By designing a reasonable core-shell structure, the dispersion and compatibility of phosphorus groups in the polymer can be ensured, thereby optimizing the toughening effect. Furthermore, the phosphorus-containing core-shell polymer toughening agent can meet the needs of various types of polymers, especially in engineering plastics requiring high toughness (such as polycarbonate, polyvinyl chloride, and polyamide), providing a more stable and durable toughening effect.

[0008] The third objective of this invention is to provide an application of a phosphorus-containing core-shell polymer toughening agent, which can be added to PC and PC / ABS alloy systems to prepare a flame-retardant, heat-resistant, and high-impact material. This can further enhance the overall performance of the polymer without significantly reducing other properties, making it promising for applications in high-performance plastics, automotive parts, electronic products, and building materials.

[0009] One of the objectives of this invention is achieved through the following technical solution: a method for preparing a phosphorus-containing core-shell polymer toughening agent, comprising the following steps: (S1) Add diphenyl ether sulfonate emulsifier, water and sodium formaldehyde sulfoxylate to the high-pressure reactor, mix and adjust the pH to 4-6; (S2) Vacuum treatment is performed on the high-pressure reactor, then butadiene, styrene, cumene hydrogen peroxide and divinylbenzene are added, and the reaction is carried out at a certain temperature. Nonionic emulsifier is added during the reaction. After the reaction is completed, the residual pressure is discharged and then filtered through a filter screen to obtain styrene-butadiene latex. (S3) Mix styrene-butadiene latex and styrene, add cumene hydrogen peroxide and stir evenly, then heat to 55-70℃ and add formaldehyde sodium bisulfite solution to react for 1-2 hours to obtain the prepolymer. (S4) Add methyl methacrylate, difunctional methacrylate and phosphate acrylate monomers to the prepolymer, and simultaneously add oxidant and reducing agent and react at a certain temperature to form a polymer latex with uniform particle size and stable emulsion. (S5) The polymer latex is spray-dried to obtain a phosphorus-containing core-shell polymer toughening agent.

[0010] The preparation method of this phosphorus-containing core-shell polymer toughening agent involves using diphenyl ether sulfonate emulsifier, adding sodium formaldehyde sulfoxylate as a reducing agent in the redox initiation system, removing oxygen inhibitors by nitrogen purging and vacuum treatment, and then adding butadiene and styrene as the main reactants, which act as soft and hard segments in the polymer, respectively. Cucurbitacin hydroperoxide acts as an oxidant in the redox system, and divinylbenzene acts as a crosslinking agent to induce polymerization. During the reaction, a nonionic emulsifier is added to stabilize the emulsion. Nitrogen purging is then used to remove residual pressure and unreacted monomers, followed by filtration to remove the gel. Styrene-butadiene latex is used as the core of the core-shell polymer, and styrene is added to increase compatibility. In this redox initiation system, cumene hydrogen peroxide is used as the oxidant, and sodium formaldehyde sulfoxylate is added dropwise as the reducing agent to initiate polymerization, activating the monomers and removing the polymerization inhibitor. Methyl methacrylate, difunctional methacrylate, and phosphate acrylate monomers are used as mixed monomers, serving as the outer shell and functional monomers of the core-shell polymer. The addition of oxidant and reducing agent continuously initiates polymerization, forming a polymer latex with uniform particle size and stable emulsion. Spray drying yields phosphorus-containing core-shell nanoparticles, i.e., phosphorus-containing core-shell polymer toughening agent, abbreviated as P-MBS. By optimizing the core-shell structure design and the introduction of phosphorus groups, the drawback of traditional toughening agents that negatively impact other properties while improving polymer toughness is overcome. This toughening agent not only significantly improves the impact toughness of polymers but also exhibits good thermal stability, anti-aging properties, and flame retardant properties, making it suitable for various types of polymer materials, especially for the modification of engineering plastics.

[0011] Preferably, in step (S2), the vacuuming process involves purging with nitrogen 2-3 times before reaching a vacuum; the reaction temperature is 50-100℃, and the reaction time is 8-10h; the residual pressure is discharged by purging with nitrogen 2-3 times; and the filter mesh size is 140-230 mesh.

[0012] Preferably, in steps (S1) and (S2), the diphenyl ether sulfonate emulsifier is sodium dodecyl diphenyl ether disulfonate; and the nonionic emulsifier is at least one of AEO-9, NP-10, MPE-20, Tween-20 and Span-80.

[0013] Preferably, in steps (S1) and (S2), the weight parts of each component are as follows: 5-10 parts of diphenyl ether sulfonate emulsifier, 2000-3000 parts of water, 2-10 parts of sodium formaldehyde sulfoxylate, 2000-3000 parts of butadiene, 50-200 parts of styrene, 10-20 parts of cumene hydrogen peroxide, 10-50 parts of divinylbenzene, and 10-50 parts of nonionic emulsifier.

[0014] Preferably, in step (S4), the reaction temperature is 55-60℃ and the reaction time is 5-8h.

[0015] Preferably, in step (S3), the concentration of the sodium formaldehyde bisulfite solution is 0.1-0.2 wt%.

[0016] Preferably, in step (S4), the difunctional methacrylate is at least one of triethylene glycol dimethacrylate, butanediol dimethacrylate, and allyl methacrylate; the phosphate acrylate monomer is at least one of SIPOMER RPM1000, RPM 2060, and RPM 2000; the oxidant is cumene hydrogen peroxide; and the reducing agent is sodium formaldehyde sulfoxylate at a concentration of 0.3-0.4 wt%.

[0017] Preferably, in steps (S3) and (S4), the weight parts of each component are as follows: 500-600 parts of styrene-butadiene latex, 30-50 parts of styrene, 0.1-0.2 parts of cumene hydrogen peroxide, 50-70 parts of sodium formaldehyde sulfoxylate solution, 30-50 parts of methyl methacrylate, 0.3-0.5 parts of difunctional methacrylate, 3-12 parts of phosphate acrylate monomer, 0.07-0.1 parts of oxidant, and 10-20 parts of reducing agent.

[0018] The second objective of this invention is achieved through the following technical solution: a phosphorus-containing core-shell polymer toughening agent, prepared by the preparation method of the phosphorus-containing core-shell polymer toughening agent as described above.

[0019] The third objective of this invention is achieved through the following technical solution: the application of a phosphorus-containing core-shell polymer toughening agent, wherein the phosphorus-containing core-shell polymer toughening agent is used for toughening modification of polycarbonate or PC / ABS alloy, wherein the modified polycarbonate comprises the following raw materials in parts by weight: 90-96 parts of PC resin, 1-3 parts of organosilicon synergistic flame retardant additive, 1-3 parts of phosphorus-containing core-shell polymer toughening agent, 0.1-0.5 parts of sulfonate flame retardant, 0.1-0.3 parts of anti-dripping agent, 0.1-0.3 parts of antioxidant, 0.02-0.1 parts of ultraviolet absorber, and 0.01-0.5 parts of lubricant.

[0020] Furthermore, the PC resin, measured according to GB / T3682-2008 at 300℃ / 1.2kg, has a melt index of 8-12 g / 10min, preferably Lihua Yiweiyuan WY-111BR or Covestro 2805; the organosilicon synergistic flame retardant additive is phenylsilsesquioxane, such as SIFR-907 or SIFR-908 from Quansheng Polycarbonate Technology Co., Ltd. (hereinafter referred to as Quansheng); the sulfonate flame retardant is selected from Quansheng KKS-A2, 870M, 5100, 6100 or Arichem. The product contains at least one of KSS, HES, and HES-2; the anti-dripping agent is selected from at least one of KT-107, KT201, and KT205 from Quansheng; the antioxidant is composed of a primary antioxidant and an auxiliary antioxidant in a weight ratio of 1:1, with the primary antioxidant selected from at least one of antioxidant 1010, antioxidant 1076, and antioxidant MD-697; the auxiliary antioxidant is selected from at least one of antioxidant 168 and antioxidant 412S; the ultraviolet absorber is selected from UV-329 or UVP-327; and the lubricant is selected from PETS.

[0021] Furthermore, the preparation method of the modified polycarbonate includes the following steps: drying PC resin at 120-130℃ until the water content is less than 0.025%, then mixing PC resin, organosilicon synergistic flame retardant additive, phosphorus-containing core-shell polymer toughening agent, sulfonate flame retardant, anti-dripping agent, antioxidant, ultraviolet absorber and lubricant by weight, adding to a twin-screw extruder, extruding and granulating to obtain modified polycarbonate; wherein, the processing temperature of each zone of the twin-screw extruder is 220-240℃, and the screw speed is 250-300 rpm.

[0022] The beneficial effects of this invention are as follows: The preparation method of the phosphorus-containing core-shell polymer toughening agent of this invention first prepares the core of the phosphorus-containing core-shell polymer—styrene-butadiene latex—by copolymerizing butadiene and styrene, and then coating the core with copolymer to form phosphorus-containing nano-core-shell polymer particles. By optimizing the core-shell structure design and the introduction method of phosphorus groups, it overcomes the drawback of traditional toughening agents that negatively impact other properties while improving polymer toughness. This toughening agent not only significantly improves the impact toughness of polymers but also has good thermal stability, anti-aging properties, and flame retardant properties, making it suitable for various types of polymer materials, especially for the modification of engineering plastics. This preparation method is simple to operate, easy to control, has high production efficiency, and low production cost, making it suitable for large-scale production.

[0023] The present invention relates to a phosphorus-containing core-shell polymer toughening agent, which not only effectively improves the toughness of polymers but also enhances their thermal stability and anti-aging properties through a rational method of introducing phosphorus groups. By designing a reasonable core-shell structure, the dispersion and compatibility of phosphorus groups in the polymer can be ensured, thereby optimizing the toughening effect. Furthermore, the phosphorus-containing core-shell polymer toughening agent can adapt to the needs of various types of polymers, especially in engineering plastics requiring high toughness (such as polycarbonate, polyvinyl chloride, and polyamide), providing a more stable and durable toughening effect.

[0024] The application of the phosphorus-containing core-shell polymer toughening agent of this invention involves adding it to PC and PC / ABS alloy systems to prepare a flame-retardant, heat-resistant, and high-impact material. By grafting reactive phosphorus-containing methacrylate onto the MBS shell, a combination of compatibility and dispersion is achieved, minimizing the impact on the overall mechanical and heat resistance properties of PC and avoiding the influence of traditional phosphate ester flame retardants on the heat resistance of PC materials through compatibility and plasticization. The addition of the phosphorus-containing core-shell polymer toughening agent improves the impact resistance and flame retardancy of PC materials. The phosphorus-containing core-shell polymer toughening agent itself is highly compatible with PC, reducing plasticization and minimizing the impact on heat distortion temperature, thus reducing the influence on the alloy's tensile strength, flexural modulus, and heat distortion temperature. This can further enhance the overall performance of the polymer without significantly reducing other properties, making it promising for applications in high-performance plastics, automotive parts, electronic products, and building materials. Attached Figure Description

[0025] Figure 1 This is the TGA thermogravimetric analysis diagram of P-MBS-01 described in Embodiment 1 of the present invention. Detailed Implementation

[0026] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0027] Example 1 A method for preparing a phosphorus-containing core-shell polymer toughening agent includes the following steps: 1) Add 5g of sodium dodecyl diphenyl ether disulfonate, 2700g of deionized water, and 5g of sodium formaldehyde sulfoxylate to a 5L stainless steel high-pressure reactor equipped with a stirrer, feeding port, and temperature control device, and adjust the pH value to 4.5. Vacuum and nitrogen purging are performed on the high-pressure reactor, with nitrogen purging three times, followed by vacuuming for later use. Then, add 2300g of butadiene, 97g of styrene, 14g of cumene hydrogen peroxide, and 25g of divinylbenzene, and react at 72℃ for 9 hours until the reactor pressure no longer decreases. During this period, an additional 37g of nonionic emulsifier AEO-9 is added. At the end of the reaction period, the residual pressure is released, and the reactor is purged with nitrogen three times, followed by filtration through a 200-mesh filter to remove the gel, yielding styrene-butadiene latex. 2) Take 500g of the prepared styrene-butadiene latex, add 35g of styrene, stir evenly, then add 0.15g of cumene hydrogen peroxide and stir evenly. Heat the reactor to 60℃, then add 60g of 0.15% sodium formaldehyde bisulfite solution dropwise. React for 120 minutes. One hour after the exothermic reaction is complete, add 35g of methyl methacrylate, 0.5g of allyl methacrylate, and 10g of RPM1000 resin and mix. At the same time, add 15g of 0.15% sodium formaldehyde bisulfite and 0.08g of cumene hydrogen peroxide dropwise. Maintain the reaction temperature at 60℃ and react for 8 hours to form a polymer latex with uniform particle size and stable emulsion. Spray dry to obtain a phosphorus-containing core-shell polymer toughening agent, designated P-MBS-01, whose TGA is as follows: Figure 1 As shown.

[0028] Example 2 A method for preparing a phosphorus-containing core-shell polymer toughening agent includes the following steps: 1) Add 5g of sodium dodecyl diphenyl ether disulfonate, 2700g of deionized water, and 5g of sodium formaldehyde sulfoxylate to a 5L stainless steel high-pressure reactor equipped with a stirrer, feeding port, and temperature control device, and adjust the pH value to 4.5. Vacuum and nitrogen purging are performed on the high-pressure reactor, with nitrogen purging three times, followed by vacuuming for later use. Then, add 2300g of butadiene, 97g of styrene, 14g of cumene hydrogen peroxide, and 25g of divinylbenzene, and react at 72℃ for 9 hours until the reactor pressure no longer decreases. During this period, an additional 37g of nonionic emulsifier AEO-9 is added. At the end of the reaction period, the residual pressure is released, and the reactor is purged with nitrogen three times, followed by filtration through a 200-mesh filter to remove the gel, yielding styrene-butadiene latex. 2) Take 500g of the prepared styrene-butadiene latex, add 35g of styrene, stir evenly, then add 0.15g of cumene hydrogen peroxide and stir evenly. Heat the reaction vessel to 60℃, then add 60g of 0.15% sodium formaldehyde bisulfite solution dropwise. React for 120 minutes. One hour after the exothermic reaction is complete, add 35g of methyl methacrylate, 0.5g of butanediol dimethacrylate and 10g of RPM2060 resin and mix. At the same time, add 15g of 0.15% sodium formaldehyde bisulfite and 0.08g of cumene hydrogen peroxide dropwise. Maintain the reaction temperature at 60℃ and react for 8 hours to form a polymer latex with uniform particle size and stable emulsion. Spray dry to obtain a phosphorus-containing core-shell polymer toughening agent, denoted as P-MBS-02.

[0029] Example 3 A method for preparing modified polycarbonate includes the following steps: 1) The Lihua Yiweiyuan WY-111BR was dried at 120℃ for 4 hours, and the moisture content of the PC resin was less than 0.02%. 2) Weigh 95.5 parts of WY-111BR after drying in step 1), 2 parts of P-MBS-01 from Example 1, 1 part of SIFR-907, 0.3 parts of KKS-A2, 0.3 parts of KT-P205, 0.3 parts of antioxidant, 0.1 parts of UV absorber UV-329, and 0.5 parts of PETS lubricant. Then add all raw materials to a high-speed mixer and mix for 3 minutes. In this embodiment, the antioxidant is composed of a primary antioxidant and a secondary antioxidant in a weight ratio of 1:1. The primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168. 3) The raw material after blending in step 2) is added to a twin-screw extruder for extrusion and granulation to obtain modified polycarbonate; wherein, the processing temperature of each zone of the twin-screw extruder is 245℃ in zone 1, 260℃ in zone 2, 265℃ in zone 3, 270℃ in zone 4, 260℃ in zone 5, 250℃ in zone 6, 240℃ in zone 7, 230℃ in zone 8, the die head temperature is 230℃, and the screw speed is 260 rpm.

[0030] Example 4 A method for preparing modified polycarbonate includes the following steps: 1) The Lihua Yiweiyuan WY-111BR was dried at 120℃ for 4 hours, and the moisture content of the PC resin was less than 0.02%. 2) Weigh out 95.5 parts of WY-111BR after drying in step 1), 2 parts of P-MBS-02 from Example 2, 1 part of SIFR-907, 0.3 parts of KKS-A2, 0.3 parts of KT-P205, 0.3 parts of antioxidant, 0.1 parts of UV absorber UV-329, and 0.5 parts of PETS lubricant. Then add all raw materials to a high-speed mixer and mix for 3 minutes. In this embodiment, the antioxidant is composed of a primary antioxidant and a secondary antioxidant in a weight ratio of 1:1. The primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168. 3) The raw material after blending in step 2) is added to a twin-screw extruder for extrusion and granulation to obtain modified polycarbonate; wherein, the processing temperature of each zone of the twin-screw extruder is 245℃ in zone 1, 260℃ in zone 2, 265℃ in zone 3, 270℃ in zone 4, 260℃ in zone 5, 250℃ in zone 6, 240℃ in zone 7, 230℃ in zone 8, the die head temperature is 230℃, and the screw speed is 260 rpm.

[0031] Example 5 A method for preparing modified polycarbonate includes the following steps: 1) The Covestro 2805 was dried at 120℃ for 4 hours, and the moisture content of the PC resin was less than 0.02%. 2) Weigh out 95.5 parts of Covestro 2805 after drying in step 1), 2 parts of P-MBS-01 from Example 1, 1 part of SIFR-907, 0.3 parts of KKS-A2, 0.3 parts of KT-P205, 0.3 parts of antioxidant, 0.1 parts of UV absorber UV-329, and 0.5 parts of PETS lubricant. Then add all raw materials to a high-speed mixer and mix for 3 minutes. In this embodiment, the antioxidant is composed of a primary antioxidant and a secondary antioxidant in a weight ratio of 1:1. The primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168. 3) The raw material after blending in step 2) is added to a twin-screw extruder for extrusion and granulation to obtain modified polycarbonate; wherein, the processing temperature of each zone of the twin-screw extruder is 245℃ in zone 1, 260℃ in zone 2, 265℃ in zone 3, 270℃ in zone 4, 260℃ in zone 5, 250℃ in zone 6, 240℃ in zone 7, 230℃ in zone 8, the die head temperature is 230℃, and the screw speed is 260 rpm.

[0032] Example 6 A method for preparing modified polycarbonate includes the following steps: 1) The Covestro 2805 was dried at 120℃ for 4 hours, and the moisture content of the PC resin was less than 0.02%. 2) Weigh out 95.5 parts of Covestro 2805 after drying in step 1), 2 parts of P-MBS-02 from Example 2, 1 part of SIFR-907, 0.3 parts of KKS-A2, 0.3 parts of KT-P205, 0.3 parts of antioxidant, 0.1 parts of UV absorber UV-329, and 0.5 parts of PETS lubricant. Then add all raw materials to a high-speed mixer and mix for 3 minutes. In this embodiment, the antioxidant is composed of a primary antioxidant and a secondary antioxidant in a weight ratio of 1:1. The primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168. 3) The raw material after blending in step 2) is added to a twin-screw extruder for extrusion and granulation to obtain modified polycarbonate; wherein, the processing temperature of each zone of the twin-screw extruder is 245℃ in zone 1, 260℃ in zone 2, 265℃ in zone 3, 270℃ in zone 4, 260℃ in zone 5, 250℃ in zone 6, 240℃ in zone 7, 230℃ in zone 8, the die head temperature is 230℃, and the screw speed is 260 rpm.

[0033] Comparative Example 1 A method for preparing modified polycarbonate includes the following steps: 1) The Lihua Yiweiyuan WY-111BR was dried at 120℃ for 4 hours, and the moisture content of the PC resin was less than 0.02%. 2) Weigh out 95.5 parts of WY-111BR, 2 parts of Rohm and Haas PARALOID EXL2690, 1 part of SIFR-907, 0.3 parts of KKS-A2, 0.3 parts of KT-P205, 0.3 parts of antioxidant, 0.1 parts of UV absorber UV-329, and 0.5 parts of PETS lubricant after drying in step 1). Then add all raw materials to a high-speed mixer and mix for 3 minutes. In this embodiment, the antioxidant is composed of a primary antioxidant and a secondary antioxidant in a weight ratio of 1:1. The primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168. 3) The raw material after blending in step 2) is added to a twin-screw extruder for extrusion and granulation to obtain modified polycarbonate; wherein, the processing temperature of each zone of the twin-screw extruder is 245℃ in zone 1, 260℃ in zone 2, 265℃ in zone 3, 270℃ in zone 4, 260℃ in zone 5, 250℃ in zone 6, 240℃ in zone 7, 230℃ in zone 8, the die head temperature is 230℃, and the screw speed is 260 rpm.

[0034] Comparative Example 2 A method for preparing modified polycarbonate includes the following steps: 1) The Lihua Yiweiyuan WY-111BR was dried at 120℃ for 4 hours, and the moisture content of the PC resin was less than 0.02%. 2) Weigh out 95.5 parts of WY-111BR, 2 parts of Japanese Kanekazu MBS M-711, 1 part of SIFR-907, 0.3 parts of KKS-A2, 0.3 parts of KT-P205, 0.3 parts of antioxidant, 0.1 parts of UV absorber UV-329, and 0.5 parts of PETS lubricant after drying in step 1). Then add all raw materials to a high-speed mixer and mix for 3 minutes. In this embodiment, the antioxidant is composed of a primary antioxidant and a secondary antioxidant in a weight ratio of 1:1. The primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168. 3) The raw material after blending in step 2) is added to a twin-screw extruder for extrusion and granulation to obtain modified polycarbonate; wherein, the processing temperature of each zone of the twin-screw extruder is 245℃ in zone 1, 260℃ in zone 2, 265℃ in zone 3, 270℃ in zone 4, 260℃ in zone 5, 250℃ in zone 6, 240℃ in zone 7, 230℃ in zone 8, the die head temperature is 230℃, and the screw speed is 260 rpm.

[0035] Comparative Example 3 A method for preparing modified polycarbonate includes the following steps: 1) The Covestro 2805 was dried at 120℃ for 4 hours, and the moisture content of the PC resin was less than 0.02%. 2) Weigh out 95.5 parts of Covestro 2805, 2 parts of Rohm and Haas Paraloide XL 2620, 1 part of SIFR-907, 0.3 parts of KKS-A2, 0.3 parts of KT-P205, 0.3 parts of antioxidant, 0.1 parts of UV absorber UV-329, and 0.5 parts of PETS lubricant after drying in step 1). Then add all raw materials to a high-speed mixer and mix for 3 minutes. In this embodiment, the antioxidant is composed of a primary antioxidant and a secondary antioxidant in a weight ratio of 1:1. The primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168. 3) The raw material after blending in step 2) is added to a twin-screw extruder for extrusion and granulation to obtain modified polycarbonate; wherein, the processing temperature of each zone of the twin-screw extruder is 245℃ in zone 1, 260℃ in zone 2, 265℃ in zone 3, 270℃ in zone 4, 260℃ in zone 5, 250℃ in zone 6, 240℃ in zone 7, 230℃ in zone 8, the die head temperature is 230℃, and the screw speed is 260 rpm.

[0036] Comparative Example 4 A method for preparing modified polycarbonate includes the following steps: 1) The Covestro 2805 was dried at 120℃ for 4 hours, and the moisture content of the PC resin was less than 0.02%. 2) Weigh out 90.8 parts of Covestro 2805, 2 parts of Rohm and Haas Paraloide XL 2620, 1 part of SIFR-907, 5 parts of phosphate flame retardant BDP, 0.3 parts of KT-P205, 0.3 parts of antioxidant, 0.1 parts of UV absorber UV-329, and 0.5 parts of PETS lubricant after drying in step 1). Then add all raw materials to a high-speed mixer and mix for 3 minutes. In this embodiment, the antioxidant is composed of a primary antioxidant and a secondary antioxidant in a weight ratio of 1:1. The primary antioxidant is antioxidant 1010 and the secondary antioxidant is antioxidant 168. 3) The raw material after blending in step 2) is added to a twin-screw extruder for extrusion and granulation to obtain modified polycarbonate; wherein, the processing temperature of each zone of the twin-screw extruder is 245℃ in zone 1, 260℃ in zone 2, 265℃ in zone 3, 270℃ in zone 4, 260℃ in zone 5, 250℃ in zone 6, 240℃ in zone 7, 230℃ in zone 8, the die head temperature is 230℃, and the screw speed is 260 rpm.

[0037] The composition and proportions of each material in Examples 3-6 and Comparative Examples 1-4 are shown in Table 1 below:

[0038] Performance testing Standard test specimens of the modified polycarbonate materials from Examples 3-6 and Comparative Examples 1-4 were taken for injection molding and their performance was tested. Molding process conditions: nozzle temperature 240℃, zone temperatures 220℃, 235℃, and 240℃, holding time 6-10s, and injection pressure 30-50MPa.

[0039] The testing methods for each performance aspect are as follows: Tensile strength: Tested according to ASTM D638 standard, test conditions 25℃; Bending strength: Tested according to ASTM D790 standard, test conditions 25℃; Lzod notched impact strength: tested according to ASTM D256 standard, test conditions 25℃; Heat distortion temperature: 1.8 MPa, tested according to ASTM D648 standard; Flame retardancy: Tested according to UL94 standard, with a sample thickness of 1.6 mm.

[0040] The test results are shown in Table 2 below:

[0041] As shown in Table 2 above, a small amount of P-MBS, combined with a small amount of sulfonate flame retardant, can achieve the UL94 V0 flame retardant rating while effectively improving impact resistance and thermal stability. In contrast, Comparative Example 4 uses a large amount of phosphate flame retardant, which has a significant impact on the material properties. Furthermore, the addition of phosphate flame retardant causes the heat distortion temperature to drop rapidly, making it unsuitable for use in higher temperature environments.

[0042] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A process for the preparation of a phosphorus-containing core-shell polymeric flexibilizer, characterized in that, It comprises the following steps: (S1), adding diphenyl ether sulfonate emulsifier, water and sodium formaldehyde sulfoxylate into a high-pressure reactor, mixing and adjusting the pH value to 4-6; (S2), vacuumizing the high-pressure reactor, then adding butadiene, styrene, cumene hydroperoxide and divinylbenzene, and reacting at a certain temperature, adding non-ionic emulsifier during the reaction, discharging the residual pressure after the reaction, then filtering with a screen to obtain butadiene-styrene latex; (S3), mixing butadiene-styrene latex and styrene, then adding cumene hydroperoxide and stirring uniformly, then heating to 55-70℃, adding sodium formaldehyde sulfoxylate solution and reacting for 1-2h to obtain a prepolymer; (S4), adding methyl methacrylate, difunctional methacrylate and phosphoacrylate monomer into the prepolymer, simultaneously adding an oxidant and a reducing agent and reacting at a certain temperature to form a polymer latex with uniform particle size and stable emulsion; (S5), obtaining the phosphorus-containing core-shell polymer toughening agent by spray drying the polymer latex.

2. The method for preparing a phosphorus-containing core-shell polymer toughening agent according to claim 1, characterized in that: In the step (S2), the vacuumizing process is replaced by nitrogen for 2-3 times and then vacuumized; the reaction temperature is 50-100℃, and the reaction time is 8-10h; the residual pressure is replaced by nitrogen for 2-3 times during the discharging process; the screen mesh size is 140-230 meshes.

3. The method for preparing a phosphorus-containing core-shell polymer toughening agent according to claim 1, characterized in that: In the steps (S1) and (S2), the diphenyl ether sulfonate emulsifier is sodium dodecyl diphenyl ether disulfonate; the non-ionic emulsifier is at least one of AEO-9, NP-10, MPE-20, Tween-20 and Span-80.

4. The method for preparing a phosphorus-containing core-shell polymer toughening agent according to claim 1, characterized in that: In the steps (S1) and (S2), the weight amount of each component is as follows: diphenyl ether sulfonate emulsifier 5-10 parts, water 2000-3000 parts, sodium formaldehyde sulfoxylate 2-10 parts, butadiene 2000-3000 parts, styrene 50-200 parts, cumene hydroperoxide 10-20 parts, divinylbenzene 10-50 parts and non-ionic emulsifier 10-50 parts.

5. The method for preparing a phosphorus-containing core-shell polymer toughening agent according to claim 1, characterized in that: In the step (S4), the reaction temperature is 55-60℃, and the reaction time is 5-8h.

6. The method of claim 1, wherein the phosphorus-containing core-shell polymer toughener is prepared by the steps of: (a) providing a phosphorus-containing core-shell polymer toughener precursor; (b) providing a phosphorus-containing core-shell polymer toughener; and (c) providing a phosphorus-containing core-shell polymer toughener. In the step (S3), the concentration of sodium formaldehyde sulfoxylate solution is 0.1-0.2wt%.

7. The method for preparing a phosphorus-containing core-shell polymer toughening agent according to claim 1, characterized in that: In the step (S4), the difunctional methacrylate is at least one of triethylene glycol dimethacrylate, butanediol dimethacrylate and allyl methacrylate, the phosphoacrylate monomer is at least one of SIPOMER RPM 1000, RPM 2060 and RPM 2000, the oxidant is cumene hydroperoxide, and the reducing agent is 0.3-0.4wt% concentration sodium formaldehyde sulfoxylate.

8. The method of claim 1, wherein the phosphorus-containing core-shell polymer toughener is prepared by the steps of: (a) providing a phosphorus-containing core-shell polymer toughener precursor; (b) providing a phosphorus-containing core-shell polymer toughener; and (c) providing a phosphorus-containing core-shell polymer toughener. In the steps (S3) and (S4), the weight amount of each component is as follows: butadiene-styrene latex 500-600 parts, styrene 30-50 parts, cumene hydroperoxide 0.1-0.2 parts, sodium formaldehyde sulfoxylate solution 50-70 parts, methyl methacrylate 30-50 parts, difunctional methacrylate 0.3-0.5 parts, phosphoacrylate monomer 3-12 parts, oxidant 0.07-0.1 parts and reducing agent 10-20 parts.

9. A phosphorus-containing core-shell polymeric flexibilizer characterized by: The phosphorus-containing core-shell polymer toughening agent is prepared by the method as claimed in any one of claims 1-8.

10. Use of a phosphorus-containing core-shell polymer flexibilizer according to claim 9, characterized in that: The phosphorus-containing core-shell polymer toughening agent is used for toughening modification of modified polycarbonate or PC / ABS alloy, and the modified polycarbonate comprises the following raw materials in parts by weight: PC resin 90-96 parts, organic silicon synergistic flame retardant additive 1-3 parts, phosphorus-containing core-shell polymer toughening agent 1-3 parts, sulfonate flame retardant 0.1-0.5 parts, anti-dripping agent 0.1-0.3 parts, antioxidant 0.1-0.3 parts, ultraviolet absorber 0.02-0.1 parts and lubricant 0.01-0.5 parts.

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