Low voc polypropylene composite material and its preparation process

Abstract

The application relates to the technical field of high polymer materials, and discloses a low-VOC polypropylene composite material and a preparation process thereof.The low-VOC polypropylene composite material comprises the following raw materials: polypropylene, maleic anhydride grafted polypropylene, fluorenyl silicone oil, benzophenone-coated talc powder, activated carbon, an antioxidant, a plasticizer and a lubricant.The fluorenyl silicone oil is prepared to improve the interfacial bonding force between the long-chain flexible structure of siloxane and the polypropylene matrix material, the fluorene ring is combined to effectively improve the thermal stability of the composite material and reduce thermal decomposition products, the activated carbon has a multistage pore structure and can physically adsorb and capture VOC components, the VOC volatilization can be effectively reduced, the environmental protection capability of the composite material is enhanced, the benzophenone-coated talc powder is added into the polypropylene composite material matrix to enhance the wear resistance and ultraviolet resistance of the polypropylene composite material, and the service life of the polypropylene composite material is effectively prolonged.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a low-VOC polypropylene composite material and its preparation process. Background Technology

[0002] With the continuous advancement of modern industrial technology, people's requirements for material performance are increasing. Traditional single materials are no longer sufficient to meet the comprehensive needs of complex application scenarios. Against this backdrop, composite materials have received widespread attention due to their ability to combine the advantages of different materials. By combining multiple materials, their strengths can be leveraged to compensate for each other's weaknesses, achieving a comprehensive improvement in various properties. Polypropylene, as a common polymer material, has become the basic raw material for many composite materials due to its advantages such as low cost and easy processing. It is widely used in fields such as home furnishings, packaging, and the automotive industry. However, polypropylene itself has poor heat resistance and is prone to softening and decomposition at high temperatures. Its wear resistance is also average, making it easy to get scratched during use. At the same time, polypropylene does not have the ability to resist ultraviolet rays and is prone to aging and embrittlement in outdoor or strong sunlight environments, directly affecting the service life of the material. Furthermore, with the increasing awareness of environmental protection, ordinary polypropylene composite materials are prone to releasing volatile organic compounds, which not only pollute the environment but also threaten the safety of users.

[0003] To address these issues, patent CN112625363B discloses a modified polypropylene material for automotive interiors with low VOC, low gloss, and low shrinkage, and its preparation method. This patent incorporates inorganic magnesium silicate molecular sieves to adsorb VOCs, resulting in a polypropylene material with low VOC content, low gloss, and low shrinkage. It also exhibits excellent mechanical and processing properties. However, the patent achieves UV resistance by directly adding UV stabilizers. While this enhances the material's UV resistance, over prolonged use, the small-molecule UV stabilizers are prone to precipitation or migration, causing the material to lose its UV resistance and thus affecting its lifespan. Summary of the Invention

[0004] The purpose of this invention is to provide a low-VOC polypropylene composite material and its preparation process, which solves the following technical problems: (1) the problem that ordinary polypropylene composite materials have high VOC content and poor heat resistance; (2) the problem that ordinary polypropylene composite materials have general wear resistance and do not have UV resistance.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A low-VOC polypropylene composite material comprises the following raw materials in parts by weight: 80-100 parts polypropylene, 25-30 parts maleic anhydride-grafted polypropylene, 10-15 parts fluorene-based silicone oil, 6-8 parts benzophenone-coated talc, 3-5 parts activated carbon, 2-3 parts antioxidant, 1-3 parts plasticizer, and 1-2 parts lubricant; wherein the fluorene-based silicone oil is prepared by reacting terminal epoxy-based silicone oil with 2-aminofluorene; wherein the benzophenone-coated talc is prepared by reacting modified talc with 5-chloro-2-hydroxybenzophenone; and wherein the modified talc is prepared by reacting talc with 4-dimethylcarbamoyl chloride.

[0007] Furthermore, the antioxidant is any one of antioxidant 1010, antioxidant 618, and antioxidant 136; the plasticizer is any one of castor oil and epoxidized soybean oil; and the lubricant is any one of stearic acid and white oil.

[0008] Furthermore, the preparation method of the fluorene-based silicone oil includes the following steps:

[0009] The terminal epoxy group silicone oil was placed in N,N-dimethylformamide, thoroughly mixed and stirred, and then 2-aminofluorene was added. The mixture was heated and stirred to react. After the reaction was completed, the product was collected by vacuum distillation to obtain fluorene-based silicone oil.

[0010] In this scheme, the epoxy group in the terminal epoxy group silicone oil structure undergoes a ring-opening reaction with the amino group in the 2-aminofluorene structure to obtain fluorene-based silicone oil. This fluorene-based silicone oil structure has multiple hydroxyl groups, which can participate in the preparation process of polypropylene composite materials. The interfacial bonding force is enhanced by the entanglement of the long silicone oil chain with the polypropylene composite matrix. At the same time, the thermally stable fluorene ring in the structure is encapsulated in the entangled structure. In combination with the long silicone oil chain, it can effectively improve the thermal stability of the composite material, absorb thermal stress, and improve the high temperature resistance of the composite material, thereby effectively reducing the VOC release rate at high temperatures.

[0011] Furthermore, the mass ratio of the terminal epoxy-based silicone oil to 2-aminofluorene is 2.5-3:2-4.

[0012] Furthermore, the epoxy value of the terminal epoxy group silicone oil is 0.02-0.05 mol / 100g.

[0013] Furthermore, the temperature of the heating and stirring reaction is 80-85℃, and the time is 8-10h.

[0014] Furthermore, the preparation method of the benzophenone-coated talc powder includes the following steps:

[0015] S1: Place talc powder and pyridine in acetone, ultrasonically disperse for 10-15 min, then introduce nitrogen gas, add 4-dimethylcarbamoyl chloride, and stir in an ice bath for 10-12 h. After the reaction is completed, filter, wash, vacuum dry and collect the product to obtain modified talc powder.

[0016] S2: The modified talc powder was placed in toluene and ultrasonically dispersed for 15-20 min. Then, 5-chloro-2-hydroxybenzophenone was added and thoroughly mixed. The mixture was then heated to reflux and reacted. After cooling to room temperature, the mixture was filtered, washed, and vacuum dried to collect the product, which yielded benzophenone-coated talc powder.

[0017] In this scheme, under the action of pyridine, the hydroxyl groups on the surface of talc powder and the acyl chloride groups in the 4-dimethylcarbamoyl chloride structure interact to obtain modified talc powder. Then, through a reflux reaction, the tertiary amine on the surface of the modified talc powder undergoes a quaternization reaction with the active chlorine in the 5-chloro-2-hydroxybenzophenone structure to obtain benzophenone-coated talc powder. This benzophenone-coated talc powder uses talc powder as a core, and after surface organic modification, it can be uniformly dispersed in polypropylene composites. The inorganic rigid core of talc powder provides supporting strength, effectively enhancing the wear resistance of polypropylene composites. At the same time, the UV absorption unit benzophenone structure is grafted onto the surface of talc powder through chemical bonding, which not only enhances the UV resistance of the composite material and prevents aging, but also fixes functional small molecules on the surface of inorganic materials, effectively preventing the migration of small molecules during long-term use. Thus, the resulting composite material can exert a long-lasting UV resistance effect and effectively extend the service life of the composite material.

[0018] Further, in step S1, the mass ratio of talc, pyridine and 4-dimethylcarbamoyl chloride is 2-4:0.5-1.5:2-3.2.

[0019] Furthermore, in step S1, the temperature of the ice bath is 0-4℃.

[0020] Further, in step S2, the mass ratio of the modified talc powder to 5-chloro-2-hydroxybenzophenone is 3.6-4.8:3-4.6.

[0021] Furthermore, in step S2, the heating and reflux reaction time is 12-15 hours.

[0022] A process for preparing a low-VOC polypropylene composite material includes the following steps:

[0023] Step 1: Add polypropylene, maleic anhydride-grafted polypropylene, and fluorene-based silicone oil to a high-speed mixer and mix evenly. Then add benzophenone-coated talc, activated carbon, antioxidant, plasticizer, and lubricant. Stir at 800-850 r / min for 1-1.5 h to form a mixture.

[0024] Step 2: Transfer the mixture to a twin-screw extruder, melt extrude and granulate, and collect the product to obtain a polypropylene composite material.

[0025] Furthermore, in step two, the processing temperature of the twin-screw extruder is 180-220℃, and the screw speed is 300-350 r / min.

[0026] The beneficial effects of this invention are:

[0027] This invention enhances the interfacial bonding between the long-chain flexible structure of siloxanes and the polypropylene matrix by preparing fluorene-based silicone oil. The combination of fluorene rings effectively improves the thermal stability of the composite material and reduces thermal decomposition products. Furthermore, the multi-level porous structure of activated carbon captures VOC components through physical adsorption, effectively reducing VOC volatilization and enhancing the environmental friendliness of the composite material. At the same time, the addition of benzophenone-coated talc to the polypropylene composite matrix effectively enhances the wear resistance of the composite material and additionally imparts excellent and long-lasting UV resistance, effectively extending the service life of the polypropylene composite material and expanding its application areas.

[0028] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a zeta potential diagram of the modified talc powder and benzophenone-coated talc powder of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The preparation method of fluorene-based silicone oil and benzophenone-coated talc in the following embodiments and comparative examples of the present invention includes the following steps:

[0033] I. Preparation of Fluorene-based Silicone Oil

[0034] 2.8 g of terminal epoxy silicone oil with an epoxy value of 0.035 mol / 100 g was placed in 80 ml of N,N-dimethylformamide, thoroughly mixed and stirred, and then 3 g of 2-aminofluorene was added. The mixture was heated to 80 °C and stirred for 8 h. After the reaction was completed, the product was collected by vacuum distillation to obtain fluorene-based silicone oil.

[0035] The nitrogen content in terminal epoxy silicone oil and fluorene-based silicone oil was tested using a 5E-CHONS2400 elemental analyzer. The test results showed that no nitrogen was detected in the terminal epoxy silicone oil, while the nitrogen content in the fluorene-based silicone oil was 0.39%. This is because the epoxy group in the structure of the terminal epoxy silicone oil reacts with the amino group in the 2-aminofluorene structure, introducing nitrogen.

[0036] II. Preparation of benzophenone-coated talc

[0037] S1: Place 3g of talc powder and 1g of pyridine in 80ml of acetone, sonicate for 10min, then introduce nitrogen gas, add 2.6g of 4-dimethylcarbamoyl chloride, stir and react in an ice bath at 0℃ for 10h, filter, wash, vacuum dry and collect the product to obtain modified talc powder.

[0038] S2: 4.2g of modified talc powder was placed in 100ml of toluene and ultrasonically dispersed for 15min. Then, 3.8g of 5-chloro-2-hydroxybenzophenone was added and thoroughly mixed. The mixture was then heated to reflux for 12h. After cooling to room temperature, the mixture was filtered, washed, and vacuum dried to collect the product, which yielded benzophenone-coated talc powder.

[0039] Zeta potential was tested on modified talc and benzophenone-coated talc. Figure 1 It can be seen that the potential value of modified talc is -11.9mV; the potential value of benzophenone-coated talc is 23.6mV. It can be seen that the potential value of modified talc is negative, while the potential value of benzophenone-coated talc is positive. This is because the tertiary amine on the surface of modified talc undergoes a quaternization reaction with 5-chloro-2-hydroxybenzophenone, generating a positively charged quaternary ammonium group.

[0040] Example 1

[0041] Preparation of polypropylene composite materials

[0042] Step 1: Add 80 parts polypropylene, 25 parts maleic anhydride-grafted polypropylene, and 10 parts fluorene silicone oil to a high-speed mixer and mix evenly. Then add 6 parts benzophenone-coated talc, 3 parts activated carbon, 2 parts antioxidant 1010, 1 part castor oil, and 1 part stearic acid. Stir at 800 r / min for 1 hour to form a mixture.

[0043] Step 2: Transfer the mixture to a twin-screw extruder, set the twin-screw extruder processing temperature to 180℃ and the screw speed to 300r / min, melt extrude and granulate, and collect the product to obtain polypropylene composite material.

[0044] Example 2

[0045] Preparation of polypropylene composite materials

[0046] Step 1: Add 90 parts polypropylene, 28 parts maleic anhydride-grafted polypropylene, and 13 parts fluorene-based silicone oil to a high-speed mixer and mix evenly. Then add 7 parts benzophenone-coated talc, 4 parts activated carbon, 2.5 parts antioxidant 618, 2 parts epoxidized soybean oil, and 1.5 parts white oil. Stir at 820 r / min for 1.2 h to form a mixture.

[0047] Step 2: Transfer the mixture to a twin-screw extruder, set the twin-screw extruder processing temperature to 200℃ and the screw speed to 320r / min, melt extrude and granulate, and collect the product to obtain polypropylene composite material.

[0048] Example 3

[0049] Preparation of polypropylene composite materials

[0050] Step 1: Add 100 parts polypropylene, 30 parts maleic anhydride-grafted polypropylene, and 15 parts fluorene silicone oil to a high-speed mixer and mix evenly. Then add 8 parts benzophenone-coated talc, 5 parts activated carbon, 3 parts antioxidant 136, 3 parts castor oil, and 2 parts stearic acid. Stir at 850 r / min for 1.5 h to form a mixture.

[0051] Step 2: Transfer the mixture to a twin-screw extruder, set the twin-screw extruder processing temperature to 220℃ and the screw speed to 350r / min, melt extrude and granulate, and collect the product to obtain polypropylene composite material.

[0052] Comparative Example 1

[0053] Preparation of polypropylene composite materials

[0054] Step 1: Add 90 parts of polypropylene and 28 parts of maleic anhydride-grafted polypropylene to a high-speed mixer and mix evenly. Then add 7 parts of benzophenone-coated talc, 4 parts of activated carbon, 2.5 parts of antioxidant 618, 2 parts of epoxidized soybean oil, and 1.5 parts of white oil. Stir at 820 r / min for 1.2 h to form a mixture.

[0055] Step 2: Transfer the mixture to a twin-screw extruder, set the twin-screw extruder processing temperature to 200℃ and the screw speed to 320r / min, melt extrude and granulate, and collect the product to obtain polypropylene composite material.

[0056] Comparative Example 2

[0057] Preparation of polypropylene composite materials

[0058] Step 1: Add 90 parts polypropylene, 28 parts maleic anhydride-grafted polypropylene, and 13 parts fluorene-based silicone oil to a high-speed mixer and mix evenly. Then add 4 parts activated carbon, 2.5 parts antioxidant 618, 2 parts epoxidized soybean oil, and 1.5 parts white oil. Stir at 820 r / min for 1.2 h to form a mixture.

[0059] Step 2: Transfer the mixture to a twin-screw extruder, set the twin-screw extruder processing temperature to 200℃ and the screw speed to 320r / min, melt extrude and granulate, and collect the product to obtain polypropylene composite material.

[0060] Comparative Example 3

[0061] Preparation of polypropylene composite materials

[0062] Step 1: Add 90 parts polypropylene, 28 parts maleic anhydride-grafted polypropylene, and 13 parts terminal epoxy silicone oil to a high-speed mixer and mix evenly. Then add 7 parts benzophenone-coated talc, 4 parts activated carbon, 2.5 parts antioxidant 618, 2 parts epoxidized soybean oil, and 1.5 parts white oil. Stir at 820 r / min for 1.2 h to form a mixture.

[0063] Step 2: Transfer the mixture to a twin-screw extruder, set the twin-screw extruder processing temperature to 200℃ and the screw speed to 320r / min, melt extrude and granulate, and collect the product to obtain polypropylene composite material.

[0064] Comparative Example 4

[0065] Preparation of polypropylene composite materials

[0066] Step 1: Add 90 parts polypropylene, 28 parts maleic anhydride-grafted polypropylene, and 13 parts fluorene-based silicone oil to a high-speed mixer and mix evenly. Then add 7 parts talc, 4 parts activated carbon, 2.5 parts antioxidant 618, 2 parts epoxidized soybean oil, and 1.5 parts white oil. Stir at 820 r / min for 1.2 h to form a mixture.

[0067] Step 2: Transfer the mixture to a twin-screw extruder, set the twin-screw extruder processing temperature to 200℃ and the screw speed to 320r / min, melt extrude and granulate, and collect the product to obtain polypropylene composite material.

[0068] Comparative Example 5

[0069] Preparation of polypropylene composite materials

[0070] Step 1: Add 90 parts polypropylene, 28 parts maleic anhydride-grafted polypropylene, and 13 parts fluorene-based silicone oil to a high-speed mixer and mix evenly. Then add 7 parts benzophenone-coated talc, 2.5 parts antioxidant 618, 2 parts epoxidized soybean oil, and 1.5 parts white oil. Stir at 820 r / min for 1.2 h to form a mixture.

[0071] Step 2: Transfer the mixture to a twin-screw extruder, set the twin-screw extruder processing temperature to 200℃ and the screw speed to 320r / min, melt extrude and granulate, and collect the product to obtain polypropylene composite material.

[0072] Performance testing

[0073] ① The polypropylene composite materials prepared in Examples 1-3 and Comparative Examples 1-5 were used as samples. 20g of the polypropylene composite material was placed in an odor bottle and baked at 80℃ for 6 hours. After cooling to room temperature, TVOC and odor level tests were performed. The specific test results are shown in Table 1 below:

[0074] Table 1: Test Results of TVOC and Odor Level of Samples

[0075]

[0076]

[0077] As shown in Table 1 above, the samples prepared in Examples 1-3 had an odor level as low as 3.0 and TVOC less than 35 μg·C / g, which are environmentally friendly and meet environmental protection requirements. In Comparative Example 1, no fluorene-based silicone oil was added, resulting in poor heat resistance and a high degree of VOC volatility. In Comparative Example 2, no benzophenone-coated talc was added, but fluorene-based silicone oil was present, resulting in a lower degree of VOC volatility and environmental protection. In Comparative Example 3, terminal epoxy-based silicone oil was directly added, and no fluorene ring was introduced into the structure, so the heat resistance was not as good as the examples, and the VOC volatility was average. In Comparative Example 4, although fluorene-based silicone oil was added, unmodified talc was directly added, which may lead to agglomeration in the matrix, resulting in reduced heat resistance and a higher degree of VOC volatility, with average environmental performance. In Comparative Example 5, no activated carbon with adsorption function was added, resulting in a high degree of VOC volatility and poor environmental performance.

[0078] ② The polypropylene composite materials prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to tablet compression to produce samples that met specifications. The samples were tested against standard GB / T1040.3-2006 at a wavelength of 313 nm and an irradiance of 0.72 m / s. 2The samples were treated in a UV aging chamber for 48 hours, and tensile strength tests were performed to determine their UV resistance. The Vicat softening temperature was tested according to standard GB / T1633-2000 to determine their high-temperature resistance. A Taber abrasion tester was used to test the abrasion resistance of the samples. Specifically, two grinding wheels were placed on the sample, and the grinding wheel speed was set to 30 r / min. The initial mass and the mass after 20,000 r of wear were recorded. The abrasion value was calculated using the formula: Abrasion Value = Initial Mass - Mass After Wear. A smaller abrasion value indicates stronger abrasion resistance. Specific test results are shown in Table 2 below.

[0079] Table 2: Test results of UV resistance, high temperature resistance and wear resistance of samples

[0080]

[0081] As shown in Table 2 above, the samples prepared in Examples 1-3 all exhibit excellent tensile strength, UV resistance, high temperature resistance, and wear resistance, meeting the requirements for use in various environments. The sample prepared in Comparative Example 1, lacking fluorene-based silicone oil, has weak high temperature resistance. The sample prepared in Comparative Example 2, lacking benzophenone-coated talc, has poor UV resistance. The sample prepared in Comparative Example 3 directly adds terminal epoxy-based silicone oil without fluorene ring modification, thus its high temperature resistance is inferior to that of the examples. The sample prepared in Comparative Example 4 directly adds unmodified talc, which may have caused agglomeration in the polypropylene matrix, resulting in its performance being inferior to that of the examples. Although no activated carbon was added to the sample prepared in Comparative Example 5, the addition of fluorene-based silicone oil and benzophenone-coated talc gives it excellent UV resistance, high temperature resistance, and wear resistance.

[0082] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0083] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, they should all fall within the protection scope of the present invention.

Claims

1. A low VOC polypropylene composite, characterized in that, The raw materials include the following weight parts: 80-100 parts of polypropylene, 25-30 parts of maleic anhydride grafted polypropylene, 10-15 parts of fluorenyl silicone oil, 6-8 parts of benzophenone coated talc, 3-5 parts of activated carbon, 2-3 parts of antioxidant, 1-3 parts of plasticizer, 1-2 parts of lubricant; the fluorenyl silicone oil is prepared by reacting epoxy-terminated silicone oil with 2-amino fluorene; the benzophenone coated talc is prepared by reacting modified talc with 5-chloro-2-hydroxybenzophenone; the modified talc is prepared by reacting talc with 4-dimethylaminocarbonyl chloride; The preparation method of the fluorenyl silicone oil comprises the following steps: The epoxy-terminated silicone oil is placed in N,N-dimethylformamide, 2-amino fluorene is fully mixed and stirred, and the reaction is carried out by heating and stirring, after the reaction is completed, vacuum distillation is carried out, and the product is collected to obtain the fluorenyl silicone oil; The epoxy value of the epoxy-terminated silicone oil is 0.02-0.05 mol / 100g; The temperature of the heating and stirring reaction is 80-85℃, and the time is 8-10h; The preparation method of the benzophenone coated talc comprises the following steps: S1: talc and pyridine are placed in acetone, ultrasonic dispersion is carried out for 10-15min, nitrogen is introduced, 4-dimethylaminocarbonyl chloride is added, ice bath is carried out, stirring reaction is carried out for 10-12h, after the reaction is completed, the product is collected after filtration, washing and vacuum drying to obtain modified talc; S2: the modified talc is placed in toluene, ultrasonic dispersion is carried out for 15-20min, 5-chloro-2-hydroxybenzophenone is added, after fully stirring and mixing, heating and reflux reaction is carried out, after the temperature is reduced to room temperature, the product is collected after filtration, washing and vacuum drying to obtain the benzophenone coated talc.

2. The low VOC polypropylene composite of claim 1, wherein, The antioxidant is any one of antioxidant 1010, antioxidant 618 and antioxidant 136; the plasticizer is any one of castor oil and epoxy soybean oil; the lubricant is any one of stearic acid and white oil.

3. The low VOC polypropylene composite of claim 1, wherein, In step S1, the temperature of the ice bath is 0-4℃.

4. The low VOC polypropylene composite of claim 1, wherein, In step S2, the time of the heating and reflux reaction is 12-15h.

5. A process for the preparation of a low VOC polypropylene composite according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: Step one, polypropylene, maleic anhydride grafted polypropylene and fluorenyl silicone oil are added into a high-speed mixer and uniformly mixed, then benzophenone coated talc, activated carbon, antioxidant, plasticizer and lubricant are added, stirring is carried out at a speed of 800-850r / min for 1-1.5h to form a mixture; Step two, the mixture is transferred into a double screw extruder, melt extrusion granulation is carried out, and the product is collected to obtain a polypropylene composite material.

6. The process for preparing a low VOC polypropylene composite material according to claim 5, characterized in that, In step two, the processing temperature of the double screw extruder is 180-220℃, and the screw rotation speed is 300-350r / min.

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