Modified PP (polypropylene) material as well as preparation method and application thereof

Abstract

The invention discloses a modified PP material as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. The modified PP material comprises matrix resin, modified mineral fiber powder and an antioxidant, the matrix resin comprises isotactic homo-polypropylene, the modified mineral fiber powder is prepared by performing surface modification treatment on mineral fiber powder through a coupling agent, and the mineral fiber powder is at least one of basalt fiber powder, wollastonite fiber powder and barium sulfate fiber powder. According to the scheme, the mechanical property, the electrical insulation property and the heat resistance of the modified PP material can be obviously improved, the structural stability, the breakdown resistance and the heat environment resistance of the insulating sleeve made of the modified PP material can be improved, and the requirements of an existing insulating sleeve for a compressor for electrical safety and structural stability are met.

Description

Technical Field

[0001] This invention relates to the technical field of polymer materials, and in particular to a modified PP material, its preparation method, and its application. Background Technology

[0002] With the continuous iteration of industrial technology, the requirements for material performance in various fields are becoming increasingly stringent, especially in equipment such as compressors, which have extremely high requirements for electrical safety and structural stability. As a key piece of equipment in industrial production, the internal insulating sleeve of a compressor is a core component ensuring stable operation and electrical safety. Therefore, developing a high-performance material for manufacturing insulating sleeves for compressors has become an important research direction in the field of materials science.

[0003] Currently, compressor insulation sleeves typically use ordinary polypropylene as the matrix material. However, ordinary polypropylene lacks sufficient rigidity, making it difficult to fully meet the structural stability requirements of high-performance compressors under complex operating conditions, and easily leading to overall deformation or damage. Secondly, because ordinary polypropylene has a low softening temperature, it is prone to softening or even thermal aging degradation in high-temperature environments, resulting in a decrease in mechanical properties and service life, which directly affects the reliability of the compressor insulation sleeve during long-term use. Summary of the Invention

[0004] To meet the requirements of electrical safety and structural stability for insulating bushings used in compressors, and to further improve the core properties of the insulating bushing raw material, such as insulation performance, mechanical properties, and heat and environmental resistance, this application provides a modified PP material, its preparation method, and its application.

[0005] Firstly, the modified PP material provided in this application adopts the following technical solution: A modified PP material, comprising the following raw materials in parts by weight: Matrix resin: 81-86 parts; Modified mineral fiber powder: 14-18 parts; Antioxidant: 0.2-0.5 parts; The matrix resin includes isotactic homopolymer polypropylene, and the modified mineral fiber powder is obtained by surface modification treatment of mineral fiber powder with a coupling agent. The mineral fiber powder is at least one of basalt fiber powder, wollastonite fiber powder, and barium sulfate fiber powder.

[0006] By adopting the above technical solution, adding modified mineral fiber powder after surface modification treatment with coupling agent, the excellent electrical insulation and rigidity enhancement effect of mineral fiber powder can significantly improve the mechanical properties, electrical insulation properties and heat resistance of modified PP material. This is beneficial to improving the structural stability, breakdown resistance and heat environment resistance of insulating sleeves made of modified PP material, thus meeting the requirements of existing compressor insulating sleeves for electrical safety and structural stability.

[0007] Optionally, the modified mineral fiber powder is prepared by surface modification treatment of basalt fiber powder with an aminosilane coupling agent, and the set length of the modified fiber powder is D. 50 ≤5μm, D 95 ≤10μm.

[0008] By adopting the above technical solutions, the structural stability of the insulating bushing can be effectively improved. Optionally, the surface modification treatment of the modified mineral fiber powder includes the following steps: First, the basalt long fibers are heated and acid-washed, thoroughly cleaned, and then dried to obtain acid-treated basalt long fibers. An aminosilane coupling agent, anhydrous ethanol, and deionized water are used to prepare an aminosilane ethanol solution. The pH value is adjusted and the solution is allowed to stand for a period of time. The acid-treated basalt long fibers are then fully immersed in the aminosilane ethanol solution after standing. After being removed and dried, the fibers are then ground, pulverized by supersonic airflow, and classified in sequence to obtain the modified mineral fiber powder.

[0009] By adopting the above technical solution, basalt long fibers are modified and then ground, pulverized by supersonic airflow, and classified to finally obtain modified mineral fiber powder of the target length. Firstly, compared with directly purchasing basalt fiber powder of the target length, the fiber cost is greatly reduced. Secondly, the surface modification process for long fibers is simpler and more convenient. Compared with the surface modification process for mineral fiber powder of micron-level length, the surface modification process is greatly simplified, and the modification cost is also saved.

[0010] Optionally, the modified mineral fiber powder is a composition of modified wollastonite fiber powder and modified barium sulfate fiber powder, and the mass ratio of the modified wollastonite fiber powder to the modified barium sulfate fiber powder is 1:(1-4). The modified wollastonite fiber powder is obtained by surface modification treatment of wollastonite fiber powder with an aminosilane coupling agent, and the modified barium sulfate fiber powder is obtained by surface modification treatment of barium sulfate fiber powder with a titanate coupling agent.

[0011] By adopting the above technical solutions, it is beneficial to improve the mechanical properties of modified PP materials, balance the relationship between rigidity and toughness in PP materials, and thus facilitate the production of insulating sleeves with better structural stability.

[0012] Different types of modified mineral fiber powder have varying effects on the structural stability of insulating bushings. Using multiple types of modified mineral fiber powder can allow for substitution in appropriate proportions without significantly affecting the structural stability of the final product. Among these, the mixed fiber prepared by mixing modified wollastonite fiber powder and modified barium sulfate fiber powder in a 1:1 mass ratio, when used as the modified mineral fiber powder, results in a modified PP material with superior structural stability for insulating bushings.

[0013] Optionally, the surface modification treatment of the modified wollastonite fiber powder includes the following steps: Prepare an aminosilane ethanol solution by mixing an aminosilane coupling agent with anhydrous ethanol and deionized water, adjust the pH value and let it stand for a period of time, then stir the wollastonite fiber powder at low speed and heat it to 75-80°C. Use a spraying process to evenly spray the aminosilane ethanol solution onto the wollastonite fiber powder. After spraying, raise the temperature to 85-88°C and continue stirring. Take it out, spread it flat and dry it thoroughly. After cooling, the modified wollastonite fiber powder is obtained.

[0014] By employing the above technical solution, the aminosilane ethanol solution is uniformly sprayed onto the wollastonite fiber powder using a spray process. This ensures sufficient contact between the coupling agent and the fiber powder, which is beneficial for improving the modification effect. It also allows for better coating of the fiber powder surface with the coupling agent, thereby enhancing the interfacial bonding between the fiber powder and the matrix resin and improving the overall performance of the modified PP material. Simultaneously, strict control of the heating temperature and stirring conditions helps ensure the stability and repeatability of the modification process, resulting in a more uniform and reliable quality of the modified wollastonite fiber powder.

[0015] Optionally, the surface modification treatment of the modified barium sulfate fiber powder includes the following steps: Prepare a titanate ethanol solution by mixing titanate coupling agent with anhydrous ethanol. Then, stir the barium sulfate fiber powder at low speed and heat it to 70-80°C. Spray the titanate ethanol solution evenly onto the barium sulfate fiber powder using a spraying process. After spraying, raise the temperature to 85-88°C and continue stirring. Remove the powder, spread it out, and dry it thoroughly. After cooling, you will get pretreated barium sulfate fiber powder.

[0016] By adopting the above technical solution, the titanate ethanol solution can also be uniformly sprayed onto the barium sulfate fiber powder using a spraying process. This effectively ensures that the coupling agent and the fiber powder are in full contact, which is beneficial to improving the modification effect. It also allows the surface of the barium sulfate fiber powder to be better coated with the coupling agent, thereby enhancing the interfacial bonding force between the fiber powder and the matrix resin. This is also beneficial to improving the overall performance of the modified PP material.

[0017] Optionally, the matrix resin further includes styrene-ethylene-butadiene-styrene block copolymer and maleic anhydride-grafted polypropylene, and the mixing mass ratio of the isotactic homopolymer polypropylene, the styrene-ethylene-butadiene-styrene block copolymer and the maleic anhydride-grafted polypropylene is (71-76):(5-10):5.

[0018] By adopting the above technical solution, the styrene-ethylene-butadiene-styrene block copolymer and maleic anhydride-grafted polypropylene can effectively improve the toughness of polypropylene and the bonding strength with modified mineral fiber powder. It can also improve the toughness and bending resistance deteriorated by the addition of modified mineral fiber powder without significantly reducing the heat resistance of the insulating sleeve. However, it should be noted that as the content of styrene-ethylene-butadiene-styrene block copolymer increases, the heat resistance of the insulating sleeve weakens, and it may even fail to maintain its tubular structure after immersion, becoming soft and limp. Therefore, the modified PP material has the best overall performance when the mixing mass ratio of isotactic homopolymer polypropylene, the styrene-ethylene-butadiene-styrene block copolymer, and the maleic anhydride-grafted polypropylene is (70-76):(5-10):5.

[0019] Optionally, the antioxidant is a composition of antioxidant 168 and antioxidant 1010, wherein the mass ratio of antioxidant 168 to antioxidant 1010 is (1-3):(1-2).

[0020] By adopting the above technical solutions, it is beneficial to prevent the performance degradation of modified PP materials due to oxidation during processing and use, thereby effectively extending the service life of the insulating sleeve.

[0021] Secondly, the preparation method of the modified PP material provided in this application adopts the following technical solution: A method for preparing a modified PP material includes the following steps: The matrix resin, mineral fiber powder, and antioxidant are thoroughly mixed and dried to obtain a mixed masterbatch. The mixed masterbatch is then melt-extruded and granulated using an extruder to obtain the modified PP material.

[0022] By adopting the above technical solution, the preparation method is simple and applicable to most existing extrusion equipment in factories, which is conducive to the rapid large-scale production of factories in the future.

[0023] Thirdly, the modified PP material provided in this application adopts the following technical solution: An application of a modified PP material for manufacturing insulating sleeves for compressors.

[0024] By adopting the above technical solutions, it is beneficial to improve the service life of the insulating sleeve in the compressor, thereby effectively preventing damage to the compressor caused by structural deformation or insulation failure of the insulating sleeve, and improving the long-term reliability of the compressor.

[0025] In summary, the technical solution of this application has at least one of the following beneficial effects: 1. By utilizing the excellent electrical insulation and rigidity reinforcement effects of mineral fiber powder, the mechanical properties, electrical insulation properties, and heat resistance properties of modified PP materials can be significantly improved.

[0026] 2. By using coupling agents to modify the surface of mineral fibers, it is beneficial to improve the compatibility between the matrix resin and the mineral fibers, thereby effectively exerting the modification effect of mineral fibers in modified PP materials. Detailed Implementation

[0027] The present application will be further described in detail below with reference to preparation examples, embodiments and comparative examples.

[0028] The basalt long fibers are all purchased from Jiangsu Tianlong basalt fiber powder untwisted yarn, with a single filament diameter of 0.5-0.8μm.

[0029] Wollastonite fiber powder was purchased from Jiangxi Huajietai Mineral Fiber's ultrafine wollastonite, specifically grade AT0028, with a particle size distribution of D. 50 ≤5μm.

[0030] Barium sulfate fiber powder was purchased from Foshan Anyi Nanotechnology, with a particle size distribution of D. 50 ≤0.3μm. Preparation Example

[0031]

Preparation Example 1

[0032] The amount of γ-aminopropyltriethoxysilane added is 5% of the mass of basalt fiber powder.

Preparation Example 2

[0033] The amount of γ-aminopropyltriethoxysilane added is 2.5% of the mass of the wollastonite fiber powder.

Preparation Example 3

[0034] The amount of isopropyl dioleoyloxy (dioctyl phosphate oxy) added is 1% of the mass of the barium sulfate fiber powder. Example

[0035]

Example 1

[0036] In this embodiment, the matrix resin is isotactic homopolymer polypropylene; the modified mineral fiber powder is modified basalt fiber powder prepared from [Preparation Example 1], and the set length of the modified mineral fiber powder is D. 50 ≤5μm, D95 ≤10μm; the antioxidant is a composition of antioxidant 168 and antioxidant 1010 mixed in a 2:1 mass ratio, i.e., including 0.2kg antioxidant 168 and 0.1kg antioxidant 1010.

[0037] A method for preparing a modified PP material includes the following steps: The matrix resin, modified mineral fiber powder, and antioxidant are thoroughly mixed and dried to obtain a mixed masterbatch. The mixed masterbatch is then melt-extruded and granulated using an extruder to obtain the modified PP material.

[0038] One application of modified PP is specifically for the preparation of insulating sleeves in compressors. The insulating sleeve has a wall thickness of 0.05 mm and an inner diameter of 1.5 mm.

[0039]

Example 2

[0040] In this embodiment, the following raw materials are specifically included: 81kg matrix resin, 18.5kg mineral fiber powder, 0.5kg antioxidant.

[0041] In this embodiment, the matrix resin is a composition of isotactic homopolymer polypropylene, styrene-ethylene-butadiene-styrene block copolymer, and maleic anhydride-grafted polypropylene mixed in a mass ratio of 71:5:5, that is, comprising 71 kg of isotactic homopolymer polypropylene, 5 kg of styrene-ethylene-butadiene-styrene block copolymer, and 5 kg of maleic anhydride-grafted polypropylene; the modified mineral fiber powder is the modified basalt fiber powder prepared from [Preparation Example 1], and the set length of the modified mineral fiber powder is D. 50 ≤5μm, D 95 ≤10μm; the antioxidant is a composition of antioxidant 168 and antioxidant 1010 mixed in a 3:2 mass ratio, that is, including 0.3kg antioxidant 168 and 0.2kg antioxidant 1010.

[0042]

Example 3

[0043] In this embodiment, the set length of the modified mineral fiber powder is D. 50 ≤15μm, D 95 ≤20μm.

[0044]

Example 4

[0045] In this embodiment, the modified mineral fiber powder is the modified wollastonite fiber powder prepared by [Preparation Example 2].

[0046]

Example 5

[0047] In this embodiment, the modified mineral fiber powder is the modified barium sulfate fiber powder prepared by [Preparation Example 3].

[0048]

Example 6

[0049] In this embodiment, the modified mineral fiber powder is a mixture of modified wollastonite fiber powder and modified barium sulfate fiber powder. The modified wollastonite fiber powder is prepared by [Preparation Example 2], and the modified barium sulfate fiber powder is prepared by [Preparation Example 3]. The mass ratio of modified wollastonite fiber powder to modified barium sulfate fiber powder is 4:1, that is, it includes 12 kg of modified wollastonite fiber powder and 3 kg of modified barium sulfate fiber powder.

[0050]

Example 7

[0051] In this embodiment, the mass ratio of modified wollastonite fiber powder to modified barium sulfate is 1:1, that is, it includes 7.5 kg of modified wollastonite fiber powder and 7.5 kg of modified barium sulfate fiber powder.

[0052]

Example 8

[0053] In this embodiment, modified wollastonite fiber powder is replaced in equal amounts with modified basalt fiber powder, wherein the modified basalt fiber powder is prepared according to [Preparation Example 1], and the set length of the modified basalt fiber powder is D. 50 ≤5μm, D 95 ≤10μm.

[0054]

Example 9

[0055] In this embodiment, the matrix resin is a composition of isotactic homopolymer polypropylene, styrene-ethylene-butadiene-styrene block copolymer and maleic anhydride grafted polypropylene, wherein the mass ratio of isotactic homopolymer polypropylene, styrene-ethylene-butadiene-styrene block copolymer and maleic anhydride grafted polypropylene is 76:5:5, that is, it includes 76 kg of isotactic homopolymer polypropylene, 5 kg of styrene-ethylene-butadiene-styrene block copolymer and 5 kg of maleic anhydride grafted polypropylene.

[0056]

Example 10

[0057] In this embodiment, the mass ratio of isotactic homopolymer polypropylene, styrene-ethylene-butadiene-styrene block copolymer and maleic anhydride grafted polypropylene is 71:10:5, which includes 71 kg of isotactic homopolymer polypropylene, 10 kg of styrene-ethylene-butadiene-styrene block copolymer and 5 kg of maleic anhydride grafted polypropylene.

[0058]

Example 11

[0059] In this embodiment, the mass ratio of isotactic homopolymer polypropylene, styrene-ethylene-butadiene-styrene block copolymer and maleic anhydride grafted polypropylene is 66:15:5, that is, it includes 66 kg of isotactic homopolymer polypropylene, 15 kg of styrene-ethylene-butadiene-styrene block copolymer and 5 kg of maleic anhydride grafted polypropylene. Comparative Example

[0060] Comparative Example 1 A modified PP material, which differs from [Example 1] in that it does not contain modified mineral fiber powder.

[0061] Comparative Example 2 A modified PP material, which differs from [Example 1] in that it does not contain modified mineral fiber powder.

[0062] In this comparative example, modified mineral fiber powder was replaced with an equal amount of basalt fiber powder, wherein the designed length of the basalt fiber powder was D. 50 ≤5μm, D 95 ≤10μm. Performance test data

[0063] Sample preparation: The modified PP materials obtained in Examples 1-11 and Comparative Examples 1-2 were melt-extruded to prepare samples, and extruded according to the shape of the insulating sleeve to obtain the test sample in the shape of the insulating sleeve. The wall thickness of the test sample was 0.05 mm and the inner diameter was 1.5 mm.

[0064] 1. Sleeve structure stability: The circumference of each sample to be tested is flattened using a pressing plate, and the edges are observed for cracks, damage, or breakage. In addition, 20 consecutive bending points on the sample to be tested are selected, and a bending test is performed using a 180° bending method. Each bending point is spaced 5 mm apart, and each bending point needs to be bent once in the forward direction and once in the reverse direction. The edges are observed for cracks, damage, or breakage, and the number of occurrences is recorded.

[0065] 2. Breakdown resistance: Insert a 1mm copper rod into the sample to be tested as one electrode, and use a conductive clamp on the outside of the sample as the other electrode, ensuring that the other electrode is in full contact with the sample. Apply a test voltage of 2kVAC for 1s. During this period, the test instrument may detect a small leakage current. Set 1mA as the upper limit. If the sample is broken down or the leakage voltage exceeds the upper limit, it is judged as unqualified; otherwise, it is recorded as qualified.

[0066] 3. Heat resistance performance: The sample to be tested is immersed in compressor oil, heated to 150°C, and continuously immersed for 500 hours to simulate the extreme working environment in the compressor. Then, its surface condition is observed and its breakdown resistance is repeatedly tested.

[0067] Table 1. Partial performance test data of insulating bushings

[0068] Based on Examples 1 and Comparative Examples 1-2, and referring to the data in Table 1, it can be seen that adding modified basalt fibers, which have undergone surface modification treatment with a coupling agent, can significantly improve the mechanical properties, electrical insulation properties, and heat resistance of the modified PP material. This, in turn, helps to improve the structural stability, breakdown resistance, and thermal environment resistance of the insulating sleeve made from the modified PP material. Although the addition of modified mineral fibers leads to a slight decrease in the toughness of the modified PP material, resulting in breakage of the insulating sleeve when flattened or bent, the overall performance of the insulating sleeve is significantly optimized.

[0069] Furthermore, as shown in Comparative Example 2, the basalt fiber without coupling agent modification does not significantly improve the overall performance of the modified PP material. This results in the insulating sleeve being significantly inferior in toughness, bending resistance, and heat resistance compared to the insulating sleeve made from the PP material modified in Example 1. This is because the compatibility between unmodified mineral fibers and polypropylene is poor. Directly adding unmodified basalt fibers cannot fully bond with the matrix resin during melt extrusion, inevitably leading to certain defects within the modified PP material. Although the modified PP material prepared by this method can improve the rigidity of the insulating sleeve to some extent, it also significantly increases the toughness degradation caused by the increased rigidity. Specifically, the resulting insulating sleeve becomes more brittle. Therefore, using unmodified mineral fibers to prepare modified PP material not only fails to effectively improve the overall performance of the resulting insulating sleeve but also results in mechanical properties inferior to those without added mineral fibers.

[0070] Combining Examples 1 and 3 with the data in Table 1, it can be seen that the length control of the modified mineral fiber powder also plays a crucial role in the structural stability of the insulating sleeve. Since the modified PP material of this application is used to prepare a thin-walled insulating sleeve with a small inner diameter, excessively long fiber powder may cause uneven dispersion and radial arrangement during the preparation of the thin-walled insulating sleeve, resulting in anisotropy inside the insulating sleeve. Therefore, when testing the sample to be tested in Example 3, its toughness and bending resistance showed poor performance.

[0071] Based on Examples 1 and 4-8, and the data in Table 1, it can be seen that different types of modified mineral fiber powder have different effects on the structural stability of the insulating bushing. Multiple types of modified mineral fiber powder can be substituted for each other in appropriate proportions without significantly affecting the structural stability of the final product. Specifically, the mixed fiber prepared by mixing modified wollastonite fiber powder and modified barium sulfate fiber powder in a 1:1 mass ratio, when used as the modified mineral fiber powder, results in a modified PP material with better structural stability for the insulating bushing.

[0072] Furthermore, regarding heat resistance, the test samples from Examples 1 and 3-8 showed no significant surface changes after immersion, and their breakdown resistance remained stable. This indicates that the addition of different modified mineral fiber powders did not have a significant negative impact on the heat resistance of the modified PP material, or the impact did not significantly affect the structural stability and breakdown resistance of the subsequently prepared insulating sleeve.

[0073] Based on Examples 7 and 9-11 and the data in Table 1, it can be seen that when the composition of the matrix resin changes, although the introduced styrene-ethylene-butadiene-styrene block copolymer and maleic anhydride-grafted polypropylene can improve the toughness of the modified PP material and the bonding strength between the matrix resin and the modified mineral fiber powder, the resulting insulating sleeve exhibits significant overall softening after hot oil immersion. Furthermore, with the increase in the content of the styrene-ethylene-butadiene-styrene block copolymer, the heat resistance of the insulating sleeve decreases significantly, and it may even fail to maintain its tubular structure after immersion, becoming completely soft and limp. Therefore, rationally selecting the matrix resin and using specific amounts of styrene-ethylene-butadiene-styrene block copolymer and maleic anhydride-grafted polypropylene in combination with polypropylene is beneficial in improving the toughness and bending resistance deteriorated by the addition of modified mineral fiber powder without significantly reducing the heat resistance of the modified PP material, thereby improving the overall performance of the insulating sleeve.

[0074] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A modified PP material, characterized in that, Includes the following quantities of raw materials: Matrix resin: 81-86 parts; Modified mineral fiber powder: 14-18 parts; Antioxidant: 0.2-0.5 parts; The matrix resin includes isotactic homopolymer polypropylene, and the modified mineral fiber powder is obtained by surface modification treatment of mineral fiber powder with a coupling agent. The mineral fiber powder is at least one of basalt fiber powder, wollastonite fiber powder, and barium sulfate fiber powder.

2. The modified PP material according to claim 1, characterized in that: The modified mineral fiber powder is prepared by surface modification of basalt fiber powder with an aminosilane coupling agent, and the specified length of the modified fiber powder is D. 50 ≤5μm, D 95 ≤10μm.

3. The modified PP material according to claim 2, characterized in that: The surface modification treatment of the modified mineral fiber powder includes the following steps: First, the basalt long fibers are heated and acid-washed, thoroughly cleaned, and then dried to obtain acid-treated basalt long fibers. An aminosilane coupling agent, anhydrous ethanol, and deionized water are used to prepare an aminosilane ethanol solution. The pH value is adjusted and the solution is allowed to stand for a period of time. The acid-treated basalt long fibers are then fully immersed in the aminosilane ethanol solution after standing. After being removed and dried, the fibers are then ground, pulverized by supersonic airflow, and classified in sequence to obtain the modified mineral fiber powder.

4. The modified PP material according to claim 1, characterized in that: The modified mineral fiber powder is a composition of modified wollastonite fiber powder and modified barium sulfate fiber powder, and the mass ratio of the modified wollastonite fiber powder to the modified barium sulfate fiber powder is 1:(1-4). The modified wollastonite fiber powder is obtained by surface modification treatment of wollastonite fiber powder with an aminosilane coupling agent, and the modified barium sulfate fiber powder is obtained by surface modification treatment of barium sulfate fiber powder with a titanate coupling agent.

5. The modified PP material according to claim 4, characterized in that: The surface modification treatment of the modified wollastonite fiber powder includes the following steps: Prepare an aminosilane ethanol solution by mixing an aminosilane coupling agent with anhydrous ethanol and deionized water, adjust the pH value and let it stand for a period of time, then stir the wollastonite fiber powder at low speed and heat it to 75-80°C. Use a spraying process to evenly spray the aminosilane ethanol solution onto the wollastonite fiber powder. After spraying, raise the temperature to 85-88°C and continue stirring. Take it out, spread it flat and dry it thoroughly. After cooling, the modified wollastonite fiber powder is obtained.

6. The modified PP material according to claim 4, characterized in that: The surface modification treatment of the modified barium sulfate fiber powder includes the following steps: Prepare a titanate ethanol solution by mixing titanate coupling agent with anhydrous ethanol. Then, stir the barium sulfate fiber powder at low speed and heat it to 70-80°C. Spray the titanate ethanol solution evenly onto the barium sulfate fiber powder using a spraying process. After spraying, raise the temperature to 85-88°C and continue stirring. Remove the powder, spread it out, and dry it thoroughly. After cooling, you will get pretreated barium sulfate fiber powder.

7. The modified PP material according to claim 1, characterized in that: The matrix resin further includes styrene-ethylene-butadiene-styrene block copolymer and maleic anhydride-grafted polypropylene, and the mixing mass ratio of the isotactic homopolymer polypropylene, the styrene-ethylene-butadiene-styrene block copolymer and the maleic anhydride-grafted polypropylene is (71-76):(5-10):

5.

8. The modified PP material according to claim 1, characterized in that: The antioxidant is a composition of antioxidant 168 and antioxidant 1010, wherein the mass ratio of antioxidant 168 to antioxidant 1010 is (1-3):(1-2).

9. A method for preparing a modified PP material, used to prepare the modified PP material as described in any one of claims 1-8, characterized in that, Includes the following steps: The matrix resin, modified mineral fiber powder, and antioxidant are thoroughly mixed and dried to obtain a mixed masterbatch. The mixed masterbatch is then melt-extruded and granulated using an extruder to obtain the modified PP material.

10. An application of a modified PP material, applicable to the modified PP material as described in any one of claims 1-8, characterized in that: Used to manufacture insulating sleeves for compressors.

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