A method for modifying polypropylene by ion coating with a transparent nucleating agent

Abstract

This invention discloses a method for modifying polypropylene transparent nucleating agents by ion coating, comprising the following steps: Step 1: Using deionized water or an ethanol-deionized water mixture as a solvent, add a cationic modifier and an anionic modifier to the solvent to prepare an ion coating solution containing the cationic and anionic modifiers; Step 2: Disperse the polypropylene transparent nucleating agent in the ion coating solution, with a solid-liquid ratio of 1g:(20~60)mL; Step 3: After ultrasonic dispersion, isothermal ion adsorption reaction, solid-liquid separation, washing, and drying, obtain the ion-coated modified polypropylene transparent nucleating agent. This invention constructs a uniform ion-modified layer on the surface of the nucleating agent through strong ionic bond interactions, preparing a core-shell structured ion-coated modified nucleating agent, significantly improving the dispersibility and nucleation efficiency of the nucleating agent in the polypropylene matrix, thereby improving the transparency, rigidity, and thermal stability of polypropylene products.

Description

Technical Field

[0001] This invention belongs to the field of polypropylene modification additives technology, specifically relating to a modification method for ion coating of transparent nucleating agents in polypropylene. Background Technology

[0002] Polypropylene, as a general-purpose polymer material, is widely used in packaging, home appliances, medical devices, and other fields due to its advantages such as low density, low cost, and excellent chemical stability. However, polypropylene itself has high crystallinity and uneven crystal size, resulting in poor transparency, which limits its application in fields requiring high transparency. Adding a transparent nucleating agent to polypropylene is the core method to improve its transparency. By introducing heterogeneous nucleation sites, the crystal size is refined, light scattering is reduced, and light transmittance is improved.

[0003] Currently, commercially available transparent nucleating agents for polypropylene mainly include sorbitol, phosphates, and metal carboxylic acid salts. Among them, phosphate nucleating agents have become a research hotspot due to their lack of formaldehyde release and excellent high-temperature resistance. However, these nucleating agents have problems such as strong surface polarity and poor compatibility with non-polar polypropylene matrices, which easily lead to agglomeration, resulting in a decrease in nucleation efficiency and limited improvement in the transparency and mechanical properties of polypropylene products.

[0004] Existing methods for modifying nucleating agents mainly include surface modification of silane coupling agents and polymer grafting. Silane coupling agent modification suffers from low chemical bonding efficiency and easy detachment of the modified layer. While polymer grafting can improve compatibility, a thicker coating layer reduces the nucleating activity of the nucleating agent, and the preparation process is complex and costly. Ion coating modification utilizes the strong interaction of ionic bonds to construct a uniform ion-modified layer on the surface of the nucleating agent. This can both regulate the surface polarity of the nucleating agent, improve compatibility with polypropylene, and ensure the exposure of nucleating active sites, making it an effective way to solve the problem of nucleating agent aggregation. However, there are currently no patent reports on the application of ion coating technology in the modification of transparent nucleating agents for polypropylene.

[0005] In the prior art, such as the transparent polypropylene material and its preparation method disclosed in CN112375304A, the transparency of the disclosed transparent polypropylene material is improved by compounding nucleating agents and additives, but the nucleating agent has poor dispersibility and the haze of the product is still high. The impact-resistant and highly transparent polypropylene composition and its preparation method disclosed in CN105566770A, while taking into account both impact resistance and transparency, do not modify the nucleating agent, thus limiting the nucleation efficiency and resulting in a minimum haze of only 9.1%.

[0006] Therefore, developing a simple and stable ion coating modification method to achieve efficient modification of polypropylene transparent nucleating agents is of great significance for improving the transparency and overall performance of polypropylene products. Summary of the Invention

[0007] In order to overcome the shortcomings of the existing technology, the present invention aims to provide a modification method for ion coating of transparent nucleating agents in polypropylene. The method aims to construct a uniform ion-modified layer on the surface of the nucleating agent through the strong interaction of ionic bonds, and prepare a core-shell structured ion-coated modified nucleating agent, which significantly improves the dispersibility and nucleation efficiency of the nucleating agent in the polypropylene matrix, thereby improving the transparency, rigidity and thermal stability of polypropylene products.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for modifying polypropylene by ion coating with a transparent nucleating agent includes the following steps; Step 1: Using deionized water or an ethanol-deionized water mixture as a solvent, add the cationic modifier and the anionic modifier to the solvent to prepare an ion coating solution containing the cationic modifier and the anionic modifier. Step 2: Disperse the polypropylene transparent nucleating agent in the ion coating solution, with a solid-liquid ratio of 1g:(20~60)mL; Step 3: After ultrasonic dispersion, isothermal ion adsorption reaction, solid-liquid separation, washing, and drying, ion-coated modified polypropylene transparent nucleating agent is obtained.

[0009] The solid-liquid ratio of the transparent polypropylene nucleating agent to the ion coating solution is controlled at 1 g:(20~60) mL. This solid-liquid ratio allows the nucleating agent particles to fully depolymerize and disperse, ensuring that the cationic and anionic modifiers are uniformly adsorbed on the particle surface to form a continuous and dense ultrathin ion coating layer. At the same time, it takes into account the stability of the ion adsorption reaction and the efficiency of industrial production, effectively improving the dispersibility and nucleation efficiency of the nucleating agent in the polypropylene matrix, and ensuring that the transparency, rigidity and thermal stability of the product are improved simultaneously.

[0010] In step 2, the transparent polypropylene nucleating agent is a phosphate-based nucleating agent, specifically one or more of sodium bis(4-tert-butylphenyl)phosphate, aluminum bis(4-tert-butylphenyl)phosphate, and sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate.

[0011] In step 1, the ion coating solution is an aqueous solution prepared with a molar ratio of cationic modifier to anionic modifier of 1:(1~1.4); the solvent is deionized water or a mixture of ethanol and deionized water.

[0012] The cationic modifier is a quaternary ammonium salt cationic surfactant, specifically one or more of hexadecyltrimethylammonium chloride, octadecyltrimethylammonium bromide, and dodecyldimethylbenzylammonium chloride; the anionic modifier is a carboxylic acid anionic compound, specifically one or more of sodium stearate, sodium oleate, and sodium dodecylbenzenesulfonate. The molar ratio of the cationic modifier to the anionic modifier is 1:(1~1.4). This ratio allows the cations and anions to form a stable, dense, electrically neutral, continuous ultrathin coating layer on the surface of the nucleating agent through ionic bonds, effectively neutralizing the surface polarity of the nucleating agent and improving its compatibility with the polypropylene matrix. At the same time, it avoids the coating layer being too thick and obscuring the active sites, ensuring maximum nucleation efficiency. If the ratio deviates from this range, problems such as incomplete coating, particle agglomeration, or coating layer detachment may occur, making it impossible to achieve the ideal modification effect.

[0013] In step 1, the volume fraction of ethanol in the ethanol-deionized water mixed solution is 15%~35%.

[0014] In step 3, the ultrasonic dispersion power is 200~500W and the time is 10~30min, which can fully open up the nucleating agent agglomerates and achieve uniform dispersion of single particles, providing a good foundation for ion coating. The isothermal ion adsorption temperature is 50-90℃, and the time is 3-7 hours, which provides suitable conditions for the self-assembly and ionic bonding of anions and cations on the nucleating agent surface, forming a continuous, dense, and robust ultrathin coating layer. Stirring at 200-400 r / min during the reaction ensures uniform mixing of the system and avoids particle sedimentation or uneven local coating. The synergistic effect of these process parameters ensures sufficient surface modification and excellent dispersibility of the nucleating agent while retaining nucleation active sites, significantly improving the transparency, rigidity, and thermal stability of polypropylene products.

[0015] By employing the aforementioned ultrasonic dispersion, isothermal ion adsorption, and stirring conditions, the nucleating agent particles can be fully deagglomerated and dispersed, avoiding agglomeration. At the same time, a suitable kinetic and thermodynamic environment is provided for the ionic bonding and uniform coating of anions and cations on the surface of the nucleating agent, ensuring the formation of a continuous, dense, thin, and strong ion coating layer. This not only improves the compatibility between the nucleating agent and the polypropylene matrix but also maximizes the retention of nucleating active sites, ultimately resulting in a significant improvement in the transparency, mechanical properties, and thermal stability of polypropylene products.

[0016] In step 3, solid-liquid separation is performed by centrifugation at a speed of 4000-6000 r / min for 5-20 min; washing is performed by washing with deionized water 2-4 times to remove unadsorbed ion modifiers. In step 3, the drying is vacuum drying, with the following conditions: drying temperature of 70~100℃ and drying time of 4~10h.

[0017] Using the above-mentioned centrifugation, washing, and vacuum drying parameters, the modified nucleating agent solid can be efficiently separated, effectively removing unadsorbed free ion modifiers and impurities, while simultaneously drying rapidly under mild conditions to preserve the nucleation agent. With an intact shell structure, no coating layer detachment, and no particle agglomeration, an ion-coated modified nucleating agent with good dispersibility, high purity, and stable performance is ultimately obtained.

[0018] The ion-coated modified polypropylene transparent nucleating agent is a phosphate-based nucleating agent with a particle size of 100~500 nm; The coating thickness of the ion-coated modified polypropylene transparent nucleating agent is 5–20 nm; The concentration of the cationic modifier in the ion coating solution is 0.05~0.15mol / L.

[0019] The vacuum degree of the vacuum drying is -0.08 to -0.10 MPa.

[0020] The beneficial effects of this invention are: This invention utilizes the strong interactions of ionic bonds to construct a uniform ion-modified layer on the surface of a nucleating agent, forming a core-shell structured modified nucleating agent. The modified layer is firmly bonded to the surface of the nucleating agent and is not easily detached, achieving uniform ion coating and nucleus formation on the surface of the nucleating agent. The shell structure and modified layer are firmly attached and do not fall off, and the surface polarity is precisely controlled. The specific process is as follows: Nucleating agent dispersion and ultrasonic deagglomeration (200~500W, 10~30min): The nucleating agent is added to the ion coating solution, and the aggregated particles are fully deagglomerated by ultrasound to form a single particle dispersion system, which provides a basis for the uniform adsorption of ions on the particle surface.

[0021] Under suitable temperature and stirring conditions, the isothermal ion adsorption reaction (50~90℃, 3~7h, stirring at 200~400r / min) allows the cationic modifier and anionic modifier to self-assemble on the surface of the nucleating agent at a molar ratio of 1:(1~1.4) through strong ionic bond interactions, forming a continuous, dense, and ultrathin uniform coating layer, thus constructing a complete nucleus. Shell structure.

[0022] Solid-liquid ratio control (1g:20~60mL): A suitable solid-liquid ratio ensures that the system concentration is moderate, ion adsorption is sufficient, and the coating layer does not accumulate or become too thick, thus ensuring the integrity of the coating without obscuring the nucleation active sites.

[0023] Centrifugation, washing and vacuum drying: Centrifugation at 4000~6000r / min and washing with deionized water 2~4 times to remove unadsorbed free ions, followed by vacuum drying at 70~100℃, so that the coating layer is further stabilized and tightly bound to the nucleating agent surface, and is not easy to fall off.

[0024] Through the above steps, the core is finally obtained. An ion-coated modified nucleating agent with a clear shell structure, uniform and firm coating layer, and surface polarity matching that of polypropylene.

[0025] When the ion-coated modified nucleating agent prepared in this invention is added to polypropylene, compared with the unmodified nucleating agent, the ion-coated modified nucleating agent of this invention can reduce the haze of polypropylene products to below 5%, increase the light transmittance to ≥90%, increase the flexural modulus by 5%~15%, and increase the heat distortion temperature by 3~8℃. The principle is as follows: The principle behind the significant improvement in transparency (reduced haze and increased light transmittance) is that ion coating modification enables the surface polarity of the nucleating agent to be highly matched with that of the non-polar polypropylene, achieving uniform dispersion of single particles in the matrix without agglomeration and eliminating light scattering centers caused by agglomeration. At the same time, the nucleating agent provides a large number of highly efficient heterogeneous nucleation sites, inducing polypropylene to form extremely fine and uniformly distributed spherulites, which greatly reduces light scattering caused by the difference in refractive index between crystalline and amorphous regions, thereby significantly reducing haze and increasing light transmittance.

[0026] The principle of improving flexural modulus (increasing rigidity) is that the modified nucleating agent is evenly dispersed and has high nucleation efficiency, which improves the crystallinity of polypropylene, refines the crystals and makes them denser. This reduces internal defects in the material, makes the stress transmission more uniform, and makes it less prone to deformation under external force, thus significantly improving the flexural modulus.

[0027] The principle behind the increase in heat distortion temperature (improved heat resistance) is that the refinement of spherulites and the improvement of crystallization enhance the heat load-bearing capacity of polypropylene, making it less prone to softening and creep under high-temperature loads, thus significantly increasing the heat distortion temperature.

[0028] The fundamental reason for the improved overall performance is that the ion coating layer is thin and strong, which improves both dispersibility and compatibility without obscuring nucleation active sites, achieving the dual advantages of high dispersion and high nucleation efficiency. Ultimately, this leads to a simultaneous improvement in the transparency, mechanical properties, and thermal stability of polypropylene, resulting in significantly better overall performance than the unmodified system.

[0029] The modification method of this invention is simple, controllable, requires no complex equipment, has mild reaction conditions, and uses readily available and inexpensive ionic modifier raw materials, making it suitable for large-scale industrial production. Furthermore, the modification process does not release any toxic or harmful substances, which meets the requirements of green chemical development. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the embodiments.

[0031] This invention discloses a modification method for ion coating of a transparent nucleating agent in polypropylene; unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels, and the transparent nucleating agent in polypropylene is a phosphate nucleating agent with a particle size of 100~500nm.

[0032] Example 1: 5 g of sodium bis(4-tert-butylphenyl) phosphate was added to 100 mL of ion-coating solution, which was an aqueous solution of hexadecyltrimethylammonium chloride and sodium stearate prepared in a molar ratio of 1:1, wherein the concentration of hexadecyltrimethylammonium chloride was 0.05 mol / L. The mixture was ultrasonically dispersed at 300 W for 20 min, and then placed in a 70 °C water bath and stirred at 300 r / min for 4 h for ion adsorption reaction. After the reaction was completed, the mixture was centrifuged at 4000 r / min for 10 min, the solid product was collected, washed three times with deionized water, and then vacuum dried at 80 °C and -0.09 MPa for 10 h to obtain ion-coated modified sodium bis(4-tert-butylphenyl) phosphate nucleating agent Cat-1.

[0033] Cat-1 was mixed with polypropylene resin (homopolymer PP, melt index 2.0 g / 10 min) at an addition rate of 0.2 wt%, and then melt-blended and extruded into granules in a twin-screw extruder. The extruder temperatures were 160℃, 170℃, 180℃, 190℃, and 185℃, and the screw speed was 200 r / min. The granules were injection molded into standard test specimens, and the performance was tested. The test results are shown in Table 1.

[0034] Example 2: 5 g of sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate was added to 50 mL of ion-coating solution, which was a mixture of ethanol and deionized water prepared by mixing octadecyltrimethylammonium bromide and sodium oleate at a molar ratio of 1:0.8, with an ethanol volume fraction of 20% and an octadecyltrimethylammonium bromide concentration of 0.01 mol / L. The mixture was ultrasonically dispersed at 200 W for 30 min, and then placed in a 60 °C water bath and stirred at 200 r / min for 6 h for ion adsorption reaction. After the reaction, the mixture was centrifuged at 3000 r / min for 15 min, the solid product was collected, washed twice with deionized water, and then vacuum dried at 60 °C and -0.08 MPa for 8 h to obtain ion-coated modified sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate nucleating agent Cat-2.

[0035] Cat-2 was mixed with polypropylene resin (homopolymer PP, melt index 2.0 g / 10 min) at an addition rate of 0.1 wt%, and polypropylene composite material was prepared according to the process in Example 1. The performance was tested, and the test results are shown in Table 1.

[0036] Example 3: 5 g of bis(4-tert-butylphenyl)aluminum phosphate was added to 250 mL of ion-coating solution, which was a mixture of ethanol and deionized water prepared by dodecyl dimethyl benzyl ammonium chloride and sodium dodecylbenzenesulfonate at a molar ratio of 1:1.2, with an ethanol volume fraction of 30% and a dodecyl dimethyl benzyl ammonium chloride concentration of 0.1 mol / L. The mixture was ultrasonically dispersed at 500 W for 10 min, and then placed in an 80 °C water bath and stirred at 400 r / min for 2 h for ion adsorption reaction. After the reaction, the mixture was centrifuged at 6000 r / min for 5 min, the solid product was collected, washed 4 times with deionized water, and then vacuum dried at 100 °C and -0.10 MPa for 4 h to obtain ion-coated modified bis(4-tert-butylphenyl)aluminum phosphate nucleating agent Cat-3.

[0037] Cat-3 was mixed with polypropylene resin (homopolymer PP, melt index 2.0 g / 10 min) at an addition rate of 0.5 wt%, and polypropylene composite material was prepared according to the process in Example 1. The performance was tested, and the test results are shown in Table 1.

[0038] Example 4: 5g of sodium bis(4-tert-butylphenyl)phosphate and 5g of aluminum bis(4-tert-butylphenyl)phosphate were mixed and added to 300mL of ion coating solution, which was an ethanol-deionized water mixture prepared by mixing hexadecyltrimethylammonium chloride and sodium oleate at a molar ratio of 1:0.9, with an ethanol volume fraction of 10% and a hexadecyltrimethylammonium chloride concentration of 0.03mol / L. The mixture was ultrasonically dispersed at 400W for 15min, and then placed in a 50℃ water bath and stirred at 250r / min for ion adsorption reaction for 5h. After the reaction, the mixture was centrifuged at 5000r / min for 8min, the solid product was collected, washed three times with deionized water, and then vacuum dried at 70℃ and -0.085MPa for 7h to obtain the ion-coated modified composite phosphate nucleating agent Cat-4.

[0039] Cat-4 was mixed with polypropylene resin (homogeneous PP, melt index 2.0 g / 10 min) at an addition rate of 0.05 wt%, and polypropylene composite material was prepared according to the process in Example 1. The performance was tested, and the test results are shown in Table 1.

[0040] Comparative Example 1: Without ion-coating modification, 10g of sodium bis(4-tert-butylphenyl)phosphate was directly vacuum-dried at 80℃ for 6h to obtain unmodified nucleating agent Cat-0. Cat-0 was mixed with polypropylene resin (homopolymer PP, melt index 2.0g / 10min) at an addition amount of 0.2wt%, and polypropylene composite material was prepared according to the process in Example 1. Performance tests were performed, and the test results are shown in Table 1.

[0041] After ion coating modification, the resulting transparent polypropylene nucleating agent exhibits a clear, uniform, and complete nucleus. The shell's microstructure is as follows: The core is a phosphate nucleating agent crystal, maintaining its original crystal form and integrity. The crystal form is regular and without lattice damage, ensuring that the nucleation active sites are fully preserved. The outer shell is a continuous, dense, and uniform ultrathin coating layer formed by the self-assembly of cationic and anionic modifiers through ionic bonds. The coating layer is 5–20 nm thick, free of pores, cracks, and localized accumulation, and firmly bonded to the core, making it difficult to detach during washing, drying, and melt processing.

[0042] The modified nucleating agent particles exhibit significantly reduced surface roughness, clearer and rounder particle boundaries, and effectively regulated surface polarity, transforming from high polarity to weak / medium polarity. This significantly improves interfacial compatibility with the non-polar polypropylene matrix. There is no adhesion or agglomeration between particles, resulting in significantly improved dispersibility. Uniform dispersion of individual particles can be achieved within the polypropylene matrix without forming agglomerates, and there is no increase in haze due to light scattering.

[0043] This microstructure ensures that the nucleating agent has high heterogeneous nucleation activity and significantly improves its dispersibility and interfacial bonding in polypropylene, ultimately enabling polypropylene products to achieve comprehensive performance improvements such as low haze, high light transmittance, high rigidity, and high thermal stability.

[0044] This invention involves adding an ion-coated modified nucleating agent to polypropylene at 0.08-0.8 wt%, followed by melt blending and extrusion granulation to obtain a high-transparency polypropylene composite material. In this composite material, the modified nucleating agent is uniformly dispersed as single particles within the polypropylene matrix without agglomeration. This induces the formation of small, uniformly distributed spherulite structures in the polypropylene, significantly reducing the spherulite size and eliminating large light-scattering crystals. Simultaneously, the nucleating agent exhibits tight interfacial bonding and excellent compatibility with the polypropylene matrix, with no significant phase separation or interfacial defects. The prepared high-transparency polypropylene composite material possesses characteristics such as low haze, high light transmittance, good rigidity, high heat distortion temperature, and processing stability, demonstrating significantly superior overall performance compared to the unmodified system. High-transparency polypropylene composite material.

[0045] Analytical methods Haze and transmittance: The haze was tested according to GB / T2410-2008 using a haze meter. The test sample was a transparent sheet with a thickness of 1 mm. Flexural modulus: Tested using a universal testing machine according to GB / T9341-2008, at a testing speed of 2 mm / min; Heat distortion temperature: Tested using a heat distortion Vicat tester according to GB / T1634.2-2004, with a load of 0.45MPa.

[0046] Table 1 Performance test results of polypropylene composites Performance indicators Cat-0 Cat-1 Cat-2 Cat-3 Cat-4 Haze (%) 10.2 4.5 3.8 4.2 4.0 Light transmittance (%) 82.5 91.8 93.2 92.5 92.8 Flexural modulus (MPa) 1520 1650 1680 1630 1660 Heat distortion temperature (°C) 102 107 109 106 108 The experimental results in Table 1 show that, compared with the unmodified nucleating agent Cat-0, the addition of the ion-coated modified nucleating agents Cat-1 to Cat-4 prepared in this invention to polypropylene significantly reduced the haze of the polypropylene composite material to below 5%, increased the light transmittance to above 90%, and also significantly improved the flexural modulus and heat distortion temperature, resulting in excellent overall performance. This is because ion coating modification effectively improves the dispersibility of the nucleating agent in the polypropylene matrix, increases the nucleation efficiency, and refines the polypropylene crystal size, thereby achieving a simultaneous improvement in transparency, mechanical properties, and thermal properties.

Claims

1. A method for modifying polypropylene by ion coating with a transparent nucleating agent, characterized in that, Includes the following steps: Step 1: Using deionized water or an ethanol-deionized water mixture as a solvent, add the cationic modifier and the anionic modifier to the solvent to prepare an ion coating solution containing the cationic modifier and the anionic modifier. Step 2: Disperse the polypropylene transparent nucleating agent in the ion coating solution at a solid-liquid ratio of 1g:(20~60)mL; Step 3: After ultrasonic dispersion, isothermal ion adsorption reaction, solid-liquid separation, washing, and drying, ion-coated modified polypropylene transparent nucleating agent is obtained.

2. The modification method for ion coating of transparent nucleating agent in polypropylene according to claim 1, characterized in that, In step 2, the transparent polypropylene nucleating agent is a phosphate-based nucleating agent, specifically one or more of sodium bis(4-tert-butylphenyl)phosphate, aluminum bis(4-tert-butylphenyl)phosphate, and sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate.

3. The modification method for ion coating of a transparent nucleating agent in polypropylene according to claim 1, characterized in that, In step 1, the ion coating solution is an aqueous solution prepared with a molar ratio of cationic modifier to anionic modifier of 1:(1~1.4).

4. The modification method for ion coating of a transparent nucleating agent in polypropylene according to claim 3, characterized in that, The cationic modifier is a quaternary ammonium salt cationic surfactant, and is one or more of hexadecyltrimethylammonium chloride, octadecyltrimethylammonium bromide, and dodecyldimethylbenzylammonium chloride; the anionic modifier is a carboxylic acid anionic compound, and is one or more of sodium stearate, sodium oleate, and sodium dodecylbenzenesulfonate.

5. The modification method for ion coating of a transparent nucleating agent in polypropylene according to claim 3, characterized in that, In step 1, the volume fraction of ethanol in the ethanol-deionized water mixed solution is 15%~35%.

6. The modification method for ion coating of a transparent nucleating agent in polypropylene according to claim 1, characterized in that, In step 3, the ultrasonic dispersion power is 200~500W and the time is 10~30min; The isothermal ion adsorption reaction is carried out at a temperature of 50~90℃ for 3~7h; stirring is performed at 200~400r / min during the reaction.

7. The modification method for ion coating of a transparent nucleating agent in polypropylene according to claim 1, characterized in that, In step 3, solid-liquid separation is performed by centrifugation at a speed of 4000-6000 r / min for 5-20 min; washing is performed by washing with deionized water 2-4 times to remove unadsorbed ion modifiers. In step 3, the drying is vacuum drying, the drying temperature is 70~100℃, and the drying time is 4~10h.

8. The modification method for ion coating of a transparent nucleating agent in polypropylene according to claim 7, characterized in that, The concentration of the cationic modifier in the ion-coated solution is 0.05~0.15 mol / L; The vacuum degree of the vacuum drying is -0.08 to -0.10 MPa.

9. The ion-coated modified polypropylene transparent nucleating agent prepared by the method according to any one of claims 1-8, characterized in that, The ion-coated modified polypropylene transparent nucleating agent is a phosphate-based nucleating agent with a particle size of 100~500nm; The coating thickness of the ion-coated modified polypropylene transparent nucleating agent is 5–20 nm.