A pp modified composite material and a preparation method thereof

Abstract

This invention specifically relates to a PP modified composite material and its preparation method. The PP modified composite material comprises the following raw materials in parts by weight: 60-70 parts PP matrix resin, 15-30 parts glass fiber, 5-10 parts inorganic filler, 3-7 parts compatibilizer, 2-6 parts amino-terminated hyperbranched polyamide, 2-5 parts glycidyl methacrylate-grafted ethylene-octene copolymer, 0.2-0.5 parts nucleating agent, 0.5-3 parts silane coupling agent, and 5-15 parts flame retardant. The PP modified composite material possesses excellent mechanical properties, heat resistance, flame retardancy, and dimensional stability. Its preparation method is stable, easy to operate and control, and has high production efficiency, making it suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of plastics technology, specifically to a modified PP composite material and its preparation method. Background Technology

[0002] Polypropylene (PP), as a general-purpose thermoplastic, has advantages such as good processability, low cost, and recyclability. However, it also has drawbacks such as low strength, poor heat resistance, and insufficient dimensional stability, which limit its application in engineering fields. In existing technologies, high-strength glass fibers are often added to low-strength polypropylene through physical blending. By utilizing the principle of combining the strengths of both materials to compensate for their weaknesses, the material is given new engineering application value.

[0003] However, existing fiber-reinforced PP composites often suffer from the following problems: 1. High glass fiber content significantly reduces toughness, making them prone to brittle fracture. Furthermore, the orientation of the glass fibers leads to anisotropy in the product, easily causing stress cracking. 2. Poor interfacial compatibility between glass fibers and the polypropylene matrix results in weak interfacial bonding, easily leading to delamination and fiber floating, resulting in a rough surface and poor gloss. 3. PP is a non-polar material, while glass fiber is a polar material; their interfacial adhesion is weak, easily leading to delamination, affecting the long-term stability of the material. Moreover, the "wick effect" of glass fibers often reduces flame retardancy, making it difficult to simultaneously meet the comprehensive requirements of high mechanical properties, high heat resistance, high dimensional stability, and flame retardancy. Therefore, developing glass fiber-reinforced PP modified composites with excellent mechanical properties, heat resistance, flame retardancy, and dimensional stability is of great significance. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this invention is to provide a PP modified composite material, which has excellent mechanical properties, heat resistance, flame retardancy and dimensional stability, significantly improved surface fiber floating phenomenon, and superior comprehensive performance.

[0005] Another objective of this invention is to provide a method for preparing PP modified composite materials, wherein the preparation method is stable, easy to operate and control, has high production efficiency, and is conducive to industrial production.

[0006] The objective of this invention is achieved through the following technical solution: 60-70 parts of PP matrix resin, 15-30 parts of glass fiber, 5-10 parts of inorganic filler, 3-7 parts of compatibilizer, 2-6 parts of amino-terminated hyperbranched polyamide, 2-5 parts of glycidyl methacrylate grafted ethylene-octene copolymer, 0.2-0.5 parts of nucleating agent, 0.5-3 parts of silane coupling agent, and 5-15 parts of flame retardant.

[0007] Furthermore, the PP matrix resin is composed of homopolymer PP and copolymer PP in a mass ratio of 2-4:1-2.

[0008] Furthermore, the homopolymer PP has a melt index of 10-25 g / 10 min at 230°C and 2.16 kg, and the copolymer PP has a melt index of 20-35 g / 10 min at 230°C and 2.16 kg. The blended matrix resin has both rigidity and toughness.

[0009] Furthermore, the length of the glass fiber is 0.1-0.4 mm. This invention controls the length of the glass fiber; when the glass fiber is too short, the reinforcing effect is poor, while when the glass fiber is too long, it is difficult to disperse, resulting in a rough product surface or warping. In the extrusion process, this invention requires a combination of extrusion processes to reduce shear strength and minimize fiber breakage.

[0010] Furthermore, the inorganic filler is at least one selected from talc, wollastonite, calcium carbonate, kaolin, barium sulfate, aluminum hydroxide, and magnesium hydroxide.

[0011] Preferably, the inorganic filler is a mixture of talc powder and wollastonite in a mass ratio of 1-3:1.

[0012] Further, the nucleating agent is at least one of α-crystal nucleating agents and β-crystal nucleating agents; the α-crystal nucleating agent is at least one of aromatic phosphate salts and carboxylic acid metal salts; the β-crystal nucleating agent is at least one of amide compounds and cyclic carboxylic acid salts.

[0013] Furthermore, the nucleating agent is a compound of α-crystal nucleating agent and β-crystal nucleating agent in a mass ratio of 0.5-2:1.

[0014] Preferably, the nucleating agent is a compound of sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl) phosphate and calcium pimecrolate in a mass ratio of 0.5-2:1. This invention, by compounding sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl) phosphate and calcium pimecrolate in a specific ratio, synergistically regulates the crystallization process to form a multiphase crystalline structure. This helps maintain the high rigidity of α-crystals while introducing the high toughness of β-crystals, achieving a good balance between rigidity and toughness. Simultaneously, the refined and uniform grain distribution helps reduce internal stress and improve the dimensional stability and surface quality of the product.

[0015] Furthermore, the compatibilizer is at least one selected from maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyolefin elastomer, and polypropylene wax. PP and glass fiber have poor bonding and are prone to delamination. This invention, by employing a compatibilizer, can improve the interfacial compatibility between PP and glass fiber, mitigate the "fiber floating phenomenon," and enhance the overall performance of the product.

[0016] Furthermore, the compatibilizer is a mixture of maleic anhydride-grafted polypropylene and polypropylene wax in a mass ratio of 2-3:1. Maleic anhydride-grafted polypropylene, as a reactive primary compatibilizer, can form chemical bonds with the surfaces of glass fibers and inorganic fillers, improving interfacial bonding strength. Polypropylene wax, as an auxiliary compatibilizer and dispersant, can improve the wetting and dispersibility of the matrix resin on glass fibers and inorganic fillers, reduce processing viscosity, decrease fiber floating, and further enhance the system's compatibility and appearance quality.

[0017] Furthermore, the flame retardant is a compound of aluminum diethylphosphonate and melamine cyanurate in a mass ratio of 1-2:1. Glass fiber itself has a "wick effect," which can sometimes exacerbate combustion. This invention, by adding a flame retardant and designing the amount of glass fiber used, enables the flame retardant performance of the PP modified composite material to reach the UL94 V-0 level.

[0018] Furthermore, the raw materials also include 0.1-3 parts of an antioxidant, wherein the antioxidant is at least one of hindered phenolic antioxidants and phosphite antioxidants.

[0019] Further, the silane coupling agent is at least one selected from γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

[0020] The PP modified composite material of this invention is reinforced by adding glass fiber to the PP matrix resin and compounding it with compatibilizers, amino-terminated hyperbranched polyamides, glycidyl methacrylate-grafted ethylene-octene copolymers, nucleating agents, and silane coupling agents. This combination of multiple interface modifications and crystallization control allows the composite material to maintain high rigidity while significantly improving toughness, dimensional stability, and flame retardancy, with a marked reduction in surface fiber floating. Specifically, the nucleating agent can be used to regulate the crystal morphology of the PP matrix, reduce internal stress, and improve heat resistance and dimensional stability. The compatibilizer, amino-terminated hyperbranched polyamides, glycidyl methacrylate-grafted ethylene-octene copolymers, and silane coupling agents work synergistically to improve the interfacial compatibility between polypropylene and glass fiber, enhance interfacial bonding, reduce fiber floating, and improve overall mechanical properties. The flame retardant can form a dense char layer during combustion, giving the material excellent flame retardant properties.

[0021] Another objective of this invention is achieved through the following technical solution: a method for preparing the above-mentioned PP modified composite material, comprising the following steps: S1 Premix: Add raw materials other than silane coupling agent and glass fiber into a mixer and mix to obtain premixed material; S2 melt extrusion: The premixed material is added to the main feed port of the extruder, and the glass fiber pretreated with silane coupling agent is added from the side feed port for melt extrusion; S3 Cooling Granulation: The extruded strip is cooled, dried, and then granulated to obtain PP modified composite material granules.

[0022] Furthermore, in step S2, the melt extrusion uses a twin-screw extruder, and the extruder temperature is set as follows: Zone 1 190-210℃, Zone 2 210-230℃, Zone 3 220-240℃, Zone 4 220-235℃, and the die head temperature is 230-240℃; the screw speed is controlled at 300-500 rpm.

[0023] Further, in step S2, the method for pretreating glass fibers with silane coupling agent is as follows: dilute the silane coupling agent with ethanol at a mass ratio of 1:4-6, add it to the glass fibers, and dry it at 75-80℃ for 1.5-2.5h for later use.

[0024] Furthermore, the preparation method of the PP modified composite material also includes step S4 post-treatment: after injection molding the granules, annealing them at 130-150℃ for 2-4 hours to eliminate internal stress and reduce warping deformation.

[0025] The preparation method of the PP modified composite material of the present invention, through the design of process steps and the control of process parameters in each step, achieves good coordination of raw materials, resulting in PP modified composite materials with excellent mechanical properties, heat resistance, flame retardancy, and dimensional stability. This helps to improve the performance of PP modified composite material products and extend their service life. The prepared PP modified composite material granules can be used for injection molding, extrusion, or compression molding for subsequent molding, ultimately forming products such as automotive parts and home appliance components.

[0026] The beneficial effects of this invention are as follows: The PP modified composite material of this invention is made by reinforcing the PP matrix resin with glass fiber, and compounding it with compatibilizers, amino-terminated hyperbranched polyamides, glycidyl methacrylate-grafted ethylene-octene copolymers, and nucleating agents. The synergistic effect of these raw materials results in a PP modified composite material with excellent mechanical properties, heat resistance, flame retardancy, and dimensional stability, effectively improving surface fiber floating. It can be used in automotive structural parts, precision components of household appliances, and other fields. The preparation method of the PP modified composite material is stable, easy to operate and control, and has high production efficiency, which is conducive to industrial production. Detailed Implementation

[0027] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0028] In some embodiments of the present invention, a PP modified composite material comprises the following raw materials in parts by weight: 60-70 parts of PP matrix resin, 15-30 parts of glass fiber, 5-10 parts of inorganic filler, 3-7 parts of compatibilizer, 2-6 parts of amino-terminated hyperbranched polyamide, 2-5 parts of glycidyl methacrylate-grafted ethylene-octene copolymer, 0.2-0.5 parts of nucleating agent, 0.5-3 parts of silane coupling agent, 10-15 parts of flame retardant, and 0.1-3 parts of antioxidant.

[0029] In some embodiments of the present invention, the PP matrix resin is composed of homopolymer PP and copolymer PP in a mass ratio of 2-4:1-2.

[0030] In some embodiments of the present invention, the homopolymer PP has a melt index of 10-25 g / 10 min at 230°C and 2.16 kg, and the copolymer PP has a melt index of 20-35 g / 10 min at 230°C and 2.16 kg. The blended matrix resin has both rigidity and toughness.

[0031] In some embodiments of the present invention, the inorganic filler is at least one selected from talc, wollastonite, calcium carbonate, kaolin, barium sulfate, aluminum hydroxide, and magnesium hydroxide.

[0032] In some embodiments of the present invention, the inorganic filler is a mixture of talc and wollastonite in a mass ratio of 1-3:1.

[0033] In some embodiments of the present invention, the nucleating agent is at least one of α-crystalline nucleating agents and β-crystalline nucleating agents; the α-crystalline nucleating agent is at least one of aromatic phosphate salts and carboxylic acid metal salts; and the β-crystalline nucleating agent is at least one of amide compounds and cyclic carboxylic acid salts.

[0034] In some embodiments of the present invention, the α-crystal nucleating agent is selected from at least one of sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl) phosphate, sodium bicyclo[2.2.1]heptane dicarboxylate, and sodium hexahydrophthalate.

[0035] In some embodiments of the present invention, the β-crystal nucleating agent is selected from at least one of N,N′-dicyclohexyl-2,6-naphthalenediamide, calcium pimecronate, zinc pimecronate, and barium pimecronate.

[0036] In some embodiments of the present invention, the nucleating agent is a compound of sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl) phosphate and calcium pimecronate in a mass ratio of 0.5-2:1.

[0037] In some embodiments of the present invention, the compatibilizer is at least one selected from maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyolefin elastomer, and polypropylene wax. The compatibilizer may be at least one selected from maleic anhydride-grafted polypropylene and maleic anhydride-grafted polyolefin elastomer, and polypropylene wax.

[0038] In some embodiments of the present invention, the compatibilizer is a mixture of maleic anhydride-grafted polypropylene and polypropylene wax in a mass ratio of 2-3:1.

[0039] In some embodiments of the present invention, the silane coupling agent is at least one selected from γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

[0040] In some embodiments of the present invention, the flame retardant is a mixture of aluminum diethylphosphonate and melamine cyanurate in a mass ratio of 1-2:1. The antioxidant is at least one of hindered phenolic antioxidants and phosphite antioxidants.

[0041] In some embodiments of the present invention, a method for preparing a PP modified composite material includes the following steps: S1 Premix: Add raw materials other than silane coupling agent and glass fiber into a mixer and mix to obtain premixed material; S2 melt extrusion: The premixed material is added to the main feed port of the extruder, and the glass fiber pretreated with silane coupling agent is added from the side feed port for melt extrusion; S3 Cooling Granulation: The extruded strip is cooled, dried, and then granulated to obtain PP modified composite material granules.

[0042] Furthermore, in step S2, the melt extrusion uses a twin-screw extruder, and the extruder temperature is set as follows: Zone 1 190-210℃, Zone 2 210-230℃, Zone 3 220-240℃, Zone 4 220-235℃, and the die head temperature is 230-240℃; the screw speed is controlled at 300-500 rpm.

[0043] Further, in step S2, the method for pretreating glass fibers with silane coupling agent is as follows: dilute the silane coupling agent with ethanol at a mass ratio of 1:4-6, add it to the glass fibers, and dry it at 75-80℃ for 1.5-2.5h for later use.

[0044] Furthermore, the preparation method of the PP modified composite material also includes step S4 post-treatment: drying the granules at 80-90℃ for 2 h for injection molding; annealing the injection molded products at 130-140℃ for 2-3 h to eliminate internal stress and reduce warpage deformation.

[0045] This embodiment provides a PP modified composite material, comprising the following raw materials in parts by weight: 65 parts PP matrix resin, 20 parts glass fiber, 8 parts inorganic filler, 5 parts amino-terminated hyperbranched polyamide, 5 parts compatibilizer, 3 parts glycidyl methacrylate grafted ethylene-octene copolymer, 0.4 parts nucleating agent, 2 parts silane coupling agent, 12 parts flame retardant, and 1 part antioxidant.

[0046] Furthermore, the PP matrix resin is composed of homopolymer PP and copolymer PP in a mass ratio of 3:1; the homopolymer PP is ExxonMobil PP1074KNE1, and the copolymer PP is Yangzi Petrochemical PPB-M30-V. The amino-terminated hyperbranched polyamide is Qingdao Haisu New Materials HD03 type amino-terminated hyperbranched polyamide; the glycidyl methacrylate-grafted ethylene-octene copolymer is Coase Chemical W5A type POE-g-GMA.

[0047] Furthermore, the inorganic filler is a mixture of talc powder and wollastonite in a mass ratio of 2:1.

[0048] Furthermore, the nucleating agent is a mixture of an α-crystal nucleating agent and a β-crystal nucleating agent in a mass ratio of 1:1; the α-crystal nucleating agent is sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate; and the β-crystal nucleating agent is calcium pimedate.

[0049] Furthermore, the compatibilizer is a mixture of maleic anhydride-grafted polypropylene and polypropylene wax in a mass ratio of 3:2. The maleic anhydride-grafted polypropylene is selected from Wengjiang Reagent PA9550 maleic anhydride-grafted polypropylene. The polypropylene wax is selected from Lion Chemical LC-503NC polypropylene wax.

[0050] Furthermore, the flame retardant is composed of aluminum diethylphosphonate and melamine cyanurate in a mass ratio of 1.5:1. The antioxidant is a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1.

[0051] In this embodiment, a method for preparing a PP modified composite material includes the following steps: S1 Premix: Add all raw materials except γ-aminopropyltriethoxysilane and glass fiber into a mixer and mix for 5 minutes to obtain premixed material; S2 Melt Extrusion: The premixed material is added to the main feed port of the extruder, and the glass fiber, which has been pretreated with γ-aminopropyltriethoxysilane in the formula, is added from the side feed port of the extruder for melt extrusion. S3 Cooling Granulation: After the extruded strip material is cooled and dried in a water cooling tank, it is cut into granules by a pelletizer to obtain PP modified composite material granules.

[0052] Furthermore, in step S2, the melt extrusion uses a twin-screw extruder, and the extruder temperature is set as follows: zone 1 200℃, zone 2 220℃, zone 3 230℃, zone 4 230℃, and die head temperature 235℃; the screw speed is controlled at 400 rpm.

[0053] Further, in step S2, the method for pretreating glass fibers with silane coupling agent is as follows: γ-aminopropyltriethoxysilane is diluted with ethanol at a mass ratio of 1:5, then added to glass fibers, and dried at 80°C for 2 hours before use.

[0054] Example 2 This embodiment provides a PP modified composite material, comprising the following raw materials in parts by weight: 60 parts PP matrix resin, 25 parts glass fiber, 5 parts inorganic filler, 3 parts amino-terminated hyperbranched polyamide, 3 parts compatibilizer, 2 parts glycidyl methacrylate grafted ethylene-octene copolymer, 0.2 parts nucleating agent, 1.5 parts silane coupling agent, 10 parts flame retardant, and 1 part antioxidant.

[0055] Furthermore, the PP matrix resin is a blend of homopolymer PP and copolymer PP in a mass ratio of 2:1.

[0056] Furthermore, the inorganic filler is a mixture of talc, wollastonite, and calcium carbonate in a mass ratio of 1:1:1.

[0057] Furthermore, the nucleating agent is a compound of an α-crystal nucleating agent and a β-crystal nucleating agent in a mass ratio of 1.5:1; the α-crystal nucleating agent is sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate; and the β-crystal nucleating agent is calcium pimedate.

[0058] Furthermore, the compatibilizer is a mixture of maleic anhydride-grafted polypropylene and polypropylene wax in a mass ratio of 2:1. The flame retardant is a mixture of aluminum diethylphosphinate and melamine cyanurate in a mass ratio of 2:1.

[0059] In this embodiment, a method for preparing a PP modified composite material includes the following steps: S1 Premix: Add all raw materials except γ-glycidyl oxypropyltrimethoxysilane and glass fiber into a mixer and mix to obtain a premixed material; S2 Melt Extrusion: The premixed material is added to the main feed port of the extruder, and the glass fiber, which has been pretreated with γ-glycidoxypropyltrimethoxysilane in the formula, is added from the side feed port of the extruder for melt extrusion. S3 Cooling Granulation: The extruded strip is cooled, dried, and then granulated to obtain PP modified composite material granules.

[0060] Furthermore, in step S2, the melt extrusion uses a twin-screw extruder, and the extruder temperature is set as follows: zone 1 190℃, zone 2 210℃, zone 3 220℃, zone 4 220℃, and die head temperature 230℃; the screw speed is controlled at 300 rpm.

[0061] The rest of the content of this embodiment is the same as that of Embodiment 1, and will not be repeated here.

[0062] Example 3 This embodiment provides a PP modified composite material, comprising the following raw materials in parts by weight: 70 parts PP matrix resin, 15 parts glass fiber, 10 parts inorganic filler, 7 parts compatibilizer, 6 parts amino-terminated hyperbranched polyamide, 5 parts glycidyl methacrylate grafted ethylene-octene copolymer, 0.5 parts nucleating agent, 3 parts silane coupling agent, 15 parts flame retardant, and 1 part antioxidant.

[0063] Furthermore, the nucleating agent is a mixture of an α-crystal nucleating agent and a β-crystal nucleating agent in a mass ratio of 2:1; the α-crystal nucleating agent is sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate; and the β-crystal nucleating agent is calcium pimedate.

[0064] Furthermore, the compatibilizer is a mixture of maleic anhydride-grafted polypropylene and polypropylene wax in a mass ratio of 3:1.

[0065] In this embodiment, a method for preparing a PP modified composite material includes the following steps: S1 Premix: Add all raw materials except γ-aminopropyltriethoxysilane and glass fiber into a mixer and mix to obtain a premixed material; S2 melt extrusion: The premixed material is added to the main feed port of the extruder, and the glass fiber pretreated with silane coupling agent is added from the side feed port for melt extrusion; S3 Cooling Granulation: The extruded strip is cooled, dried, and then granulated to obtain PP modified composite material granules.

[0066] Furthermore, in step S2, the melt extrusion uses a twin-screw extruder, and the extruder temperature is set as follows: Zone 1 210℃, Zone 2 230℃, Zone 3 235℃, Zone 4 235℃, and the die head temperature is 240℃; the screw speed is controlled at 500 rpm.

[0067] The rest of the content of this embodiment is the same as that of Embodiment 1, and will not be repeated here.

[0068] Comparative Example 1 The difference between this comparative example and Example 1 is that no terminal amino hyperbranched polyamide was added to the PP modified composite material of this comparative example, and an equal amount of PP matrix resin was used instead.

[0069] Comparative Example 2 The difference between this comparative example and Example 1 is that the PP modified composite material in this comparative example does not contain glycidyl methacrylate-grafted ethylene-octene copolymer, but is replaced with an equal amount of PP matrix resin.

[0070] Comparative Example 3 The difference between this comparative example and Example 1 is that the nucleating agent in the PP modified composite material of this comparative example is only sodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl) phosphate, with an addition amount of 0.4 parts, and no β-crystal nucleating agent calcium pimedate is added. The remaining raw materials and preparation methods are the same as in Example 1.

[0071] The PP modified composite material granules obtained in Example 1 and Comparative Examples 1-3 were dried at 80℃ for 2 h and then injection molded. The injection molded products were annealed at 135℃ for 2.5 h to obtain PP modified composite material samples. The performance of the samples was measured, and the test results are shown in Table 1 below: Tensile strength testing was performed according to ASTM D638. Flexural strength testing was performed according to ASTM D790. Flexural modulus testing was performed according to ASTM D790. Notched impact strength testing was performed according to ASTM D256 using a cantilever beam impact testing machine. Heat distortion temperature testing was performed according to ASTM D648, with a test condition of 1.82 MPa and a heating rate of 120 °C / h. Shrinkage was performed according to ASTM D955, with a test condition of 23 °C for 24 hours.

[0072] Flame retardancy tests were conducted on Examples 1 and Comparative Examples 1-3, and the flame retardancy rating of both Examples 1 and Comparative Examples 1-3 reached UL94 V-0 (1.6mm). Visual inspection of surface fiber floating phenomena was performed on Examples 1 and Comparative Examples 1-3. It was found that the injection molded product of Example 1 had a smooth surface with no visible fiber floating; the surface of Comparative Examples 1-2 showed obvious fiber floating, with white streaks and spots visible to the naked eye; and the surface of Comparative Example 3 showed slight fiber floating, with faintly visible white streaks and spots.

[0073] As can be seen from the table above, the present invention, through the synergistic effect of terminal amino hyperbranched polyamide, glycidyl methacrylate-grafted ethylene-octene copolymer, and nucleating agents, significantly improves the notched impact strength of Example 1 compared to Comparative Examples 1-3. Although the tensile strength, flexural strength, and flexural modulus are slightly lower than those of Comparative Examples 1-3, the sample still exhibits better tensile strength, flexural strength, and flexural modulus performance, and significantly improved impact toughness. Its dimensional stability is superior to that of Comparative Examples 1-3, and it possesses good thermal stability, effectively solving the problem of surface fiber floating. The present invention significantly improves toughness, dimensional stability, and surface appearance while maintaining high rigidity, demonstrating excellent comprehensive performance.

[0074] In summary, the PP modified composite material of this invention is reinforced by adding glass fibers pre-treated with a silane coupling agent to the PP matrix resin, and compounded with compatibilizers, amino-terminated hyperbranched polyamides, glycidyl methacrylate-grafted ethylene-octene copolymers, and nucleating agents. The synergistic effect of these raw materials allows the composite material to maintain high rigidity while possessing good notched impact strength, achieving a UL94 V-0 flame retardancy rating, and significantly improving surface fiber floating. It also exhibits good dimensional stability, making it suitable for manufacturing precision parts, with tolerances controllable to the ±0.05mm level. The PP modified composite material obtained by this invention possesses excellent mechanical properties, heat resistance, flame retardancy, and dimensional stability, demonstrating superior overall performance.

[0075] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A PP-modified composite material, characterized in that: The raw materials include the following parts by weight: 60-70 parts PP matrix resin, 15-30 parts glass fiber, 5-10 parts inorganic filler, 3-7 parts compatibilizer, 2-6 parts amino-terminated hyperbranched polyamide, 2-5 parts glycidyl methacrylate grafted ethylene-octene copolymer, 0.2-0.5 parts nucleating agent, 0.5-3 parts silane coupling agent, and 5-15 parts flame retardant.

2. The PP modified composite material according to claim 1, characterized in that: The PP matrix resin is composed of homopolymer PP and copolymer PP in a mass ratio of 2-4:1-2.

3. The PP modified composite material according to claim 1, characterized in that: The homopolymer PP has a melt index of 10-25 g / 10 min at 230℃ and 2.16 kg, and the copolymer PP has a melt index of 20-35 g / 10 min at 230℃ and 2.16 kg.

4. The PP modified composite material according to claim 1, characterized in that: The inorganic filler is at least one of talc, wollastonite, calcium carbonate, kaolin, barium sulfate, aluminum hydroxide, and magnesium hydroxide.

5. The PP modified composite material according to claim 1, characterized in that: The nucleating agent is at least one of α-crystalline nucleating agents and β-crystalline nucleating agents; the α-crystalline nucleating agent is at least one of aromatic phosphate salts and carboxylic acid metal salts; the β-crystalline nucleating agent is at least one of amide compounds and cyclic carboxylic acid salts.

6. The PP modified composite material according to claim 1, characterized in that: The nucleating agent is a mixture of α-crystal nucleating agent and β-crystal nucleating agent in a mass ratio of 0.5-2:

1.

7. The PP modified composite material according to claim 1, characterized in that: The compatibilizer is at least one of maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyolefin elastomer, and polypropylene wax.

8. The PP modified composite material according to claim 1, characterized in that: The compatibilizer is a mixture of maleic anhydride-grafted polypropylene and polypropylene wax in a mass ratio of 2-3:

1.

9. A method for preparing a PP modified composite material according to any one of claims 1-8, characterized in that: Includes the following steps: S1 Premix: Add raw materials other than glass fiber and silane coupling agent into a mixer and mix to obtain premixed material; S2 melt extrusion: The premixed material is added to the main feed port of the extruder, and the glass fiber pretreated with silane coupling agent is added from the side feed port for melt extrusion; S3 Cooling Granulation: The extruded strip is cooled, dried, and then granulated to obtain PP modified composite material granules.

10. The method for preparing the PP modified composite material according to claim 9, characterized in that: In step S2, the melt extrusion uses a twin-screw extruder, and the extruder temperature is set as follows: Zone 1 190-210℃, Zone 2 210-230℃, Zone 3 220-240℃, Zone 4 220-235℃, and the die head temperature is 230-240℃; the screw speed is controlled at 300-500 rpm.

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