High-fluidity high-impact polypropylene special material and production process thereof

Abstract

The invention discloses a high-flowability and high-impact polypropylene special material, relates to the field of olefin polymerization, and solves the problem that rigidity and toughness of an existing product are not easy to consider to influence the shrinkage rate of the product. The special material comprises the following raw materials in parts by weight: 100 parts of polypropylene powder; 0.10 to 0.26 part of a compound additive; the compound additive A is prepared from the following components in parts by weight: 0.02 to 0.04 part of an oxidizing agent IRGANOX 1010; 0.03 to 0.08 part of an antioxidant IRGAFOS 168, and 0.03 to 0.08 part of an antioxidant; 0.03 to 0.08 part of hydrotalcite (DHT); and the content of the nucleating agent Mailinkine HPN715 is 0.02 to 0.06 part. The preparation process comprises the following steps: extruding and granulating, namely adding the composite additive into polypropylene powder obtained by polymerization, and granulating by using a double-screw extruder. The special material can regulate and control microstructures of a polypropylene phase and a rubber phase, improves the particle size of the rubber phase and the compatibility of the two phases, and improves the rigid-tough balance performance of the material.

Description

Technical Field

[0001] This invention relates to the field of olefin polymerization, and in particular to a high-flow, high-impact polypropylene special material and its production process. Background Technology

[0002] High-flow, high-impact copolymer polypropylene resin is mainly used in washing machine parts, furniture, household goods, home appliances, daily chemical products, and the automotive industry. Current technologies struggle to balance rigidity and toughness in produced products, resulting in lower crystallization temperatures, slower crystallization rates, and reduced shrinkage. Due to the difficulty in balancing and controlling the overall performance of high-flow, high-impact copolymer polypropylene, production is challenging, domestic output is low, and there remains a significant shortage of materials for washing machines and automobiles, necessitating imports of raw materials from Europe, Japan, South Korea, and Singapore. Summary of the Invention

[0003] This invention addresses the problem in existing specialty polypropylene materials where it is difficult to balance rigidity and toughness, and where low crystallization temperature and slow crystallization rate affect product shrinkage. It provides a high-flow, high-impact polypropylene specialty material. This material utilizes Basel's Spheripol process technology to control the microstructure of the polypropylene and rubber phases, improving the rubber phase particle size and the compatibility of the two phases, thereby enhancing the material's rigidity-toughness balance. This invention also provides a production process for this high-flow, high-impact polypropylene specialty material.

[0004] The present invention solves its problems through the following technical solution:

[0005] This invention provides a high-flow, high-impact polypropylene special material, comprising polypropylene powder and composite additives; the raw materials are composed of the following by weight:

[0006] Polypropylene powder: 100 parts;

[0007] The compound additive is 0.10-0.26 parts;

[0008] The composite additive is composite additive A;

[0009] The composite additive A has the following composition by weight:

[0010] Antioxidant IRGANOX 1010: 0.02-0.04 parts;

[0011] Antioxidant IRGAFOS168: 0.03-0.08 parts;

[0012] Hydrotalcite DHT: 0.03-0.08 parts;

[0013] The nucleating agent, Melink HPN715, is used in quantities of 0.02-0.06 parts.

[0014] Preferably, the weight ratio of the antioxidant IRGANOX 1010, antioxidant IRGANOX 168, hydrotalcite DHT, and nucleating agent MILLINK HPN715 is 3:6:6:4.

[0015] Preferably, the composite additive is JHC-7681 composite additive.

[0016] Another aspect of the present invention provides a production process for a high-flow, high-impact polypropylene special material, comprising the following steps:

[0017] Step 1: Prepolymerization reaction

[0018] Propylene undergoes a prepolymerization reaction under the action of a reaction catalyst to obtain a prepolymerized powder;

[0019] Step 2: Propylene polymerization reaction

[0020] Impact-resistant copolymer polypropylene powder is formed through the homopolymerization of propylene and the copolymerization of ethylene and propylene in the presence of propylene homopolymer.

[0021] Step 3: Extrusion Granulation

[0022] Unreacted catalyst was deactivated by hot nitrogen and then dried to obtain polymer powder. Composite additives were added to the polymer powder, and the mixture was granulated using a twin-screw extruder to obtain the polymer product.

[0023] Preferably, the composite additive used in the extrusion granulation process of step 3 is JHC-7681 composite additive or composite additive A.

[0024] Preferably, the amount of composite additive added to the powder obtained by polymerization in step 3 is 1000-2600 ppm; more preferably 1800-1900 ppm.

[0025] Preferably, the twin-screw extruder is used for granulation, and the barrel temperature is controlled between 210℃ and 260℃.

[0026] Preferably, the process of the prepolymerization reaction in step 1 includes:

[0027] The reaction catalyst consists of a main catalyst, a co-catalyst, and an electron donor;

[0028] Under nitrogen protection, the reaction catalyst is mixed with oil and pre-contacted before entering the prepolymerization reactor, where it undergoes a prepolymerization reaction with propylene that has entered through an online mixer. The prepolymerization is carried out in a propylene liquid phase environment, in a small loop at a temperature of 20℃-30℃ and a pressure of 2.8Mpa-3.2Mpa, with a residence time of 10-20 minutes.

[0029] Preferably, the main catalyst is catalyst CS-2-B or CS-2-C; the co-catalyst is triethylaluminum (TEAL); and the electron donor is Donor C.

[0030] Preferably, the mass ratio of the co-catalyst to the main catalyst is 3-5; the mass ratio of the co-catalyst to propylene is 0.15-0.25 (kg / t); and the mass ratio of the co-catalyst to the electron donor is 2-10 (kg / kg).

[0031] Preferably, the grease is a mixture of white oil and petroleum jelly in a volume ratio of 2:1.

[0032] Preferably, the process for the propylene polymerization reaction in step 2 includes:

[0033] The prepolymerized powder undergoes homopolymerization of propylene with liquid propylene and hydrogen in a loop reactor;

[0034] The generated homopolymer powder enters the gas phase reactor GPR to achieve binary copolymerization. Ethylene and propylene monomers are fed into the GPR at a pre-set ratio to polymerize and generate rubber substances. Inside the GPR, the binary copolymer grows in the homopolymer spheres, and the spheres eventually become a mixture of homopolymer and dimer tightly bound together. Propylene and ethylene undergo copolymerization reaction in this environment to form impact-resistant copolymer polypropylene powder.

[0035] Preferably, in the homopolymerization reaction of propylene, the reaction temperature is 69-71℃ and the reaction pressure is 3.9MPa; the hydrogen content in the first and second ring tubes is 4300-5900ppm (mol% / mol%).

[0036] Preferably, the reaction conditions for the copolymerization of propylene and ethylene are: reaction temperature 75℃-80℃, reaction pressure 1.05-1.35MPa, ethylene / (ethylene+propylene) mass ratio of 0.35-0.42, and vinyl mass ratio controlled at 7%-12%.

[0037] Preferably, the melt index of the formed impact-resistant copolymer polypropylene powder is controlled at 25-35 g / 10 min.

[0038] Compared with the above-mentioned background technology, the present invention has the following beneficial effects:

[0039] The present invention relates to a production process for high-flow, high-impact polypropylene special materials, which adopts the Spheripol process technology from Basel Company to control the microstructure of the polypropylene phase and the rubber phase, thereby improving the particle size of the rubber phase and the compatibility of the two phases, and enhancing the material's rigidity-toughness balance.

[0040] The present invention relates to a production process for high-flow, high-impact polypropylene special materials. It employs specialized composite additives to refine crystal grains, accelerate crystallization rate, increase crystal density, control crystal form, improve crystallinity, regulate crystal structure, improve shrinkage rate and warpage performance, further improve rigidity-toughness balance, and enhance the overall performance of polypropylene materials.

[0041] The impact-resistant polypropylene prepared by this invention achieves a melt index of 25-35 g / 10 min, with relatively stable melt index control. The increased crystallization temperature leads to a faster crystallization rate, resulting in lower shrinkage and reduced warping of the polypropylene products. The product exhibits excellent rigidity-toughness balance, meeting the mechanical and processing performance requirements of raw materials in washing machine components, furniture, household goods, home appliances, daily chemical products, and the automotive industry. Detailed Implementation

[0042] 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.

[0043] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials and reagents used in the following examples are commercially available unless otherwise specified.

[0044] This invention is not limited to the specific embodiments listed below. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations made to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0045] The main catalyst CS-2-B or CS-2-C is manufactured by Yingkou Xiangyang Catalyst Co., Ltd.

[0046] The manufacturer of the co-catalyst triethylaluminum (TEAL) is Yingkou Xiangyang Catalyst Co., Ltd.

[0047] The manufacturer of the electron-conducting DonorC is Yingkou Zhonghe Additives Co., Ltd.

[0048] A production process for a high-flow, high-impact polypropylene special material includes the following steps:

[0049] The propylene polymerization reaction is carried out on a polypropylene unit, utilizing the Spheripol process control technology and employing a dual-loop reactor. The main equipment includes a prepolymerization reactor, a dual-loop reactor, a gas-phase reactor, and an extrusion granulator.

[0050] Step 1: Prepolymerization reaction

[0051] The main catalyst is CS-2-B or CS-2-C, the co-catalyst is TEAL (triethylaluminum), and the electron donor is Donor C. The catalyst (composed of the main catalyst, co-catalyst, and electron donor) is mixed with grease (a mixture of white oil and petrolatum at a volume ratio of 2:1) under nitrogen protection and, after pre-contact, enters the prepolymerization reactor to undergo prepolymerization with propylene that has passed through an online mixer. Prepolymerization is carried out in a propylene liquid-phase bulk environment in a small loop at a temperature of 20℃-30℃ and a pressure of 2.8MPa-3.2MPa, with a residence time of 10-20 minutes. The ratio of co-catalyst to main catalyst is 3-5, the TEAL / propylene ratio is 0.15-0.25 (mass ratio, kg / t), and the TEAL / DONOR ratio is 2-10 (mass ratio, kg / kg).

[0052] Step 2: Propylene polymerization reaction

[0053] This includes the homopolymerization of propylene and the copolymerization of ethylene and propylene in the presence of propylene homopolymers.

[0054] Prepolymerized powder undergoes homopolymerization with liquid propylene and hydrogen in a loop reactor at a temperature of 69-71℃ and a pressure of 3.9 MPa. The hydrogen flow rate in the first and second loops is 4300-5900 ppm (mol% / mol%). The resulting homopolymer powder enters a gas-phase reactor (GPR) for binary copolymerization. Ethylene and propylene monomers are fed into the GPR at a pre-set ratio to polymerize and form a rubbery substance. Within the GPR, the binary copolymer grows within the homopolymer spheres, eventually transforming the spheres into a tightly bound mixture of homopolymer and dimer. Propylene and ethylene then copolymerize in this environment at a temperature of 75℃-80℃ and a pressure of 1.05-1.35 MPa. The ethylene / (ethylene + propylene) ratio is 0.35-0.42 (mol% / mol%), and the vinyl content is controlled at 7%-12% (mass ratio), forming an impact-resistant copolymer polypropylene powder with a melt index controlled at 25-35 g / 10 min.

[0055] Step 3: Extrusion Granulation

[0056] The unreacted catalyst is deactivated by hot nitrogen and then dried to obtain polymer powder. 1000-2600 ppm of composite additives, preferably 1800-1900 ppm, are added to the polymer powder. Granulation is performed using a twin-screw extruder, with the barrel temperature controlled at 210℃-260℃.

[0057] The composite additive is composite additive A or JHC-7681 composite additive.

[0058] The composite additive A has the following composition by weight:

[0059] Antioxidant IRGANOX 1010: 2-4 parts;

[0060] Antioxidant IRGAFOS168: 3-8 parts;

[0061] Hydrotalcite DHT: 3-8 parts;

[0062] The nucleating agent, Melink HPN715, is 2-6 parts.

[0063] The JHC-7681 composite additive was purchased from Beijing Jihaichuan Technology Development Co., Ltd.

[0064] Example 1

[0065] The propylene polymerization reaction is carried out on a polypropylene unit, utilizing the Spheripol process control technology and employing a dual-loop reactor. The main equipment includes a prepolymerization reactor, a dual-loop reactor, a gas-phase reactor, and an extrusion granulator.

[0066] Step 1: Prepolymerization reaction

[0067] The main catalyst is CS-2-B, the co-catalyst is TEAL, and the electron donor is DonorC.

[0068] Under nitrogen protection, the catalyst, mixed with grease (a mixture of white oil and petrolatum at a volume ratio of 2:1), is pre-contaminated and then fed into a prepolymerization reactor to undergo prepolymerization with propylene that has passed through an online mixer. Prepolymerization is carried out in a propylene liquid-phase bulk environment in a small loop at 23°C and 2.9 MPa for 15 minutes. The ratio of co-catalyst to main catalyst is 3.5, the TEAL / propylene ratio is 0.15 (mass ratio, kg / t), and the TEAL / DONOR ratio is 3.2 (mass ratio, kg / kg).

[0069] Step 2: Propylene polymerization reaction

[0070] This includes the homopolymerization of propylene and the copolymerization of ethylene and propylene in the presence of propylene homopolymers. Prepolymerized powder undergoes homopolymerization with liquid propylene and hydrogen in a loop reactor at a temperature of 69°C and a pressure of 3.9 MPa. The hydrogen supply in the first and second loops is 4500 ppm (mass ratio). The resulting homopolymer powder enters a gas-phase reactor (GPR) for binary copolymerization. Ethylene and propylene monomers are fed into the GPR at a pre-set ratio to polymerize and form a rubber-like substance. Within the GPR, the binary copolymer grows within the homopolymer spheres, eventually transforming the spheres into a tightly bound mixture of homopolymer and dimer. Propylene and ethylene then copolymerize in this environment at a temperature of 76°C and a pressure of 1.05 MPa, with an ethylene / (ethylene + propylene) ratio of 0.38 and vinyl groups controlled at 8%, forming an impact-resistant copolymer polypropylene powder with a melt index controlled at approximately 26 g / 10 min.

[0071] Step 3: Extrusion Granulation

[0072] The unreacted catalyst was deactivated by hot nitrogen and then dried to obtain polymer powder. 1800 ppm of JHC-7681 composite additive was added to the polymer powder; granulation was performed using a twin-screw extruder, with the barrel temperature controlled between 210℃ and 260℃.

[0073] The process parameters and physical property data of the resulting polymer products are shown in Tables 1 and 2.

[0074] Example 2

[0075] Example 2 used the same prepolymerization and polymerization process conditions as Example 1. The differences from Example 1 were: the catalyst used was Yingkou Xiangyang CS-2-C; the types and amounts of additives were different; and the resulting powder contained 300 ppm of IRGANOX 1010 additive, 600 ppm of IRGANOX 168 additive, 600 ppm of hydrotalcite (DHT), and 400 ppm of Mellink HPN715. Process parameters and the physical properties of the resulting polymer product are shown in Tables 1 and 2.

[0076] Comparative Example 1

[0077] The compound antioxidants consist of 300 ppm IRGANOX 1010 additive, 600 ppm IRGAFOS168 additive, and 600 ppm DHT (hydrotalcite). Process parameters and the physical properties of the resulting polymer products are shown in Tables 1 and 2.

[0078] Test case

[0079] The performance of the polymer products in Examples 1-2 and Comparative Example 1 was tested.

[0080] The polymer data in the examples and comparative examples were obtained using the following test methods:

[0081] ①Melt mass flow rate (MFR): Determined according to the method described in GB / T3682-2000; measured using a CEAST 7026 melt flow indexer at 230℃ and a load of 2.16 kg.

[0082] ②Tensile strength: Determined according to the method described in GB / T1040-2006 using a ZWICK BT1-FR005TN.A50 universal testing machine;

[0083] ③ Flexural modulus: determined according to the method described in GB / T9341-2008; using a ZWICK BT1-FR005TN.A50 universal testing machine;

[0084] ④ Impact strength: Tested according to the method described in GB / T1843-2008, using ZWICK's BPI-5.5STAC.

[0085] ⑤ Oxidation induction period: Determined according to the method described in GB / T2951.1-1994. Using a Q20 DSC instrument from Waters China Co., Ltd., 10±0.5mg of sample was heated to 200℃ at a rate of 20℃ / min under nitrogen protection, held at the temperature for 5min, then nitrogen was stopped and oxygen was introduced at a flow rate of 50mL / min.

[0086] ⑥ Melting point / crystallization temperature: Determined according to the method described in GB / T 19466-2004. Using a Q20 DSC from Waters China Ltd., under N2 protection at a flow rate of 50 ml / min, 5 ± 0.5 mg of sample was first heated from room temperature to 200 °C at a heating rate of 10 °C / min and held at that temperature for 5 min to eliminate thermal history. Then, the sample was cooled to 40 °C at a cooling rate of 10 °C / min and held at that temperature for 5 min. Finally, the sample was heated to 200 °C again at a heating rate of 10 °C / min.

[0087] ⑦ Ash content: determined according to the method described in GB / T9345-2008;

[0088] ⑧ Vinyl groups; determined according to the method described in SN / T3298-2012;

[0089] ⑨ Yellow Index: Determined according to the method described in HG / T 3862-2006 using a yellow index meter from HUNTERLAB.

[0090] The polymer property analysis results for Examples 1-2 and Comparative Example 1 are shown in Table 2.

[0091] 1) Results of physical property analysis of polymer product in Example 1:

[0092] Particle melt mass flow rate (g / 10min): 30.3; Tensile yield stress (MPa): 24.6;

[0093] Flexural modulus (MPa): 1300;

[0094] Impact strength of simply supported beam (kJ / m2): 9.8;

[0095] Yellow Index: -2.0;

[0096] Ash content / mass fraction (%): 0.0129;

[0097] Melting point (°C): 166;

[0098] Crystallization temperature (°C): 128;

[0099] Oxidation induction period at 200℃ (min): 7;

[0100] 2) Results of polymer property analysis for Example 2: Pellet melt mass flow rate (g / 10min): 27; Tensile yield stress (MPa): 25.6;

[0101] Flexural modulus (MPa): 1347;

[0102] Impact strength of simply supported beam (kJ / m2): 9.0;

[0103] Yellow index: 0.1;

[0104] Ash content / mass fraction (%): 0.0261;

[0105] Melting point (°C): 165;

[0106] Crystallization temperature (°C): 131;

[0107] Oxidation induction period at 200℃ (min): 3;

[0108] 3) Comparative Example 1 polymer product physical property analysis results: Pellet melt mass flow rate (g / 10min): 28.6; Tensile yield stress (MPa): 23.0;

[0109] Flexural modulus (MPa): 982;

[0110] Impact strength of simply supported beam (kJ / m2): 8.6;

[0111] Yellow Index: -2.0;

[0112] Ash content / mass fraction (%): 0.0124;

[0113] Melting point (°C): 163;

[0114] Crystallization temperature (°C): 117;

[0115] Oxidation induction period at 200℃ (min): 9.

[0116] Table 1

[0117]

[0118] Table 2

[0119]

[0120] As shown in Table 2, compared with Comparative Example 1, the impact-resistant polypropylene prepared in Examples 1-2 of the present invention has a melt index of 25-35 g / 10 min, the melt index is more stable, the product's flexural modulus and impact strength are improved, the rigidity and toughness are well balanced, the crystallization temperature is increased, the crystallization rate is faster, the shrinkage rate of polypropylene products is smaller, and it is not easy to warp or deform.

[0121] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the implementation methods of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of the present invention.

Claims

1. A high-flow, high-impact polypropylene special material, characterized in that: Includes polypropylene powder and composite additives; the composition of each raw material by weight is as follows: Polypropylene powder: 100 parts; The compound additive is 0.10-0.26 parts; The composite additive is composite additive A; The composite additive A has the following composition by weight: Antioxidant IRGANOX 1010: 0.02-0.04 parts; Antioxidant IRGAFOS 168: 0.03-0.08 parts; Hydrotalcite DHT: 0.03-0.08 parts; The nucleating agent, Melink HPN715, is used in quantities of 0.02-0.06 parts.

2. The high-flow, high-impact polypropylene special material according to claim 1, characterized in that: The antioxidant IRGANOX 1010, antioxidant IRGAFOS 168, hydrotalcite DHT, and nucleating agent Mellink HPN715 are present in a weight ratio of 3:6:6:

4.

3. The high-flow, high-impact polypropylene special material according to claim 1, characterized in that: The composite additive is JHC-7681 composite additive.

4. A production process for a high-flow, high-impact polypropylene special material according to any one of claims 1-3, characterized in that: Includes the following steps: Step 1: Prepolymerization reaction Propylene undergoes a prepolymerization reaction under the action of a reaction catalyst to obtain a prepolymerized powder; Step 2: Propylene Polymerization Reaction Impact-resistant copolymer polypropylene powder is formed through the homopolymerization of propylene and the copolymerization of ethylene and propylene in the presence of propylene homopolymer. Step 3: Extrusion Granulation Unreacted catalyst was deactivated by hot nitrogen and then dried to obtain polymer powder. Composite additives were added to the polymer powder, and the mixture was granulated using a twin-screw extruder to obtain the polymer product.

5. The production process of a high-flow, high-impact polypropylene special material according to claim 4, characterized in that: The composite additive used in step 3, the extrusion granulation process, is either JHC-7681 composite additive or composite additive A.

6. The production process of a high-flow, high-impact polypropylene special material according to claim 4, characterized in that: The amount of composite additive added to the powder obtained by polymerization in step 3 is 1000-2600 ppm; preferably 1800-1900 ppm.

7. The production process of a high-flow, high-impact polypropylene special material according to claim 4, characterized in that: The twin-screw extruder is used for granulation, and the barrel temperature is controlled between 210℃ and 260℃.

8. The production process of a high-flow, high-impact polypropylene special material according to claim 4, characterized in that: The process of the prepolymerization reaction in step 1 includes: The reaction catalyst consists of a main catalyst, a co-catalyst, and an electron donor; Under nitrogen protection, the reaction catalyst is mixed with oil and pre-contacted before entering the prepolymerization reactor, where it undergoes a prepolymerization reaction with propylene that has entered through an online mixer. Prepolymerization is carried out in a propylene liquid phase bulk environment, in a small loop at a temperature of 20℃-30℃ and a pressure of 2.8Mpa-3.2Mpa, with a residence time of 10-20 minutes.

9. The production process of a high-flow, high-impact polypropylene special material according to claim 8, characterized in that: The main catalyst is catalyst CS-2-B or CS-2-C; the co-catalyst is triethylaluminum (TEAL); and the electron donor is Donor C.

10. The production process of a high-flow, high-impact polypropylene special material according to claim 8, characterized in that: The mass ratio of the co-catalyst to the main catalyst is 3-5; the mass ratio of the co-catalyst to propylene is 0.15-0.25 kg / t; and the mass ratio of the co-catalyst to the electron donor is 2-10 kg / kg.

11. The production process of a high-flow, high-impact polypropylene special material according to claim 8, characterized in that: The grease is a mixture of white oil and petroleum jelly in a volume ratio of 2:

1.

12. The production process of a high-flow, high-impact polypropylene special material according to claim 4, characterized in that: The process of the propylene polymerization reaction in step 2 includes: The prepolymerized powder undergoes homopolymerization of propylene with liquid propylene and hydrogen in a loop reactor; The generated homopolymer powder enters the gas phase reactor GPR to achieve binary copolymerization. Ethylene and propylene monomers are fed into the GPR at a pre-set ratio to polymerize and generate rubber substances. Inside the GPR, the binary copolymer grows in the homopolymer spheres, and the spheres eventually become a mixture of homopolymer and dimer tightly bound together. Propylene and ethylene undergo copolymerization reaction in this environment to form impact-resistant copolymer polypropylene powder.

13. The production process of a high-flow, high-impact polypropylene special material according to claim 12, characterized in that: In the homopolymerization of propylene, the reaction temperature is 69-71℃ and the reaction pressure is 3.9MPa; the hydrogen content in the first and second ring tubes is 4300-5900ppm (mol% / mol%).

14. The production process of a high-flow, high-impact polypropylene special material according to claim 12, characterized in that: The reaction conditions for the copolymerization of propylene and ethylene are as follows: reaction temperature 75℃-80℃, reaction pressure 1.05-1.35MPa, ethylene / (ethylene+propylene) mass ratio of 0.35-0.42, and vinyl mass ratio controlled at 7%-12%.

15. The production process of a high-flow, high-impact polypropylene special material according to claim 12, characterized in that: The melt index of the resulting impact-resistant copolymer polypropylene powder is controlled at 25-35 g / 10 min.

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