Polypropylene composite material, and preparation method and application thereof

Abstract

The application discloses a kind of polypropylene composite material and preparation method and application thereof, belong to high polymer material technical field.Polypropylene composite material includes following component according to weight fraction: polypropylene resin 50~80 parts;Chopped carbon fiber 20~40 parts;Polar graft A 3~5 parts;Polar graft B 2~5 parts;Beta nucleating agent 0.05~0.3 parts;Antioxidant 0.2~2 parts;Wherein, the polar graft A is maleic anhydride graft, and the mass grafting rate of maleic anhydride is 0.7~1.3%;Polar graft B is glycidyl methacrylate graft, and the mass grafting rate of glycidyl methacrylate is 0.6-0.8%.The polypropylene composite material of the application can significantly improve the impact performance of the material under the premise of maintaining the mechanical properties of the material, so that the material has high tensile strength, high tensile modulus and high impact strength.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to a polypropylene composite material, its preparation method, and its application. Background Technology

[0002] Polypropylene materials have the characteristics of low density, chemical resistance and excellent cost performance, and are widely used in automotive interior and exterior parts.

[0003] Carbon fiber is a new type of high-strength, high-modulus fiber material. Its main material properties are composed of carbon elements. It has advantages such as high temperature resistance, friction resistance, water resistance, corrosion resistance, and low density. As a reinforcing material, it is added to polymers to obtain polymer composite materials, which can greatly improve the comprehensive mechanical properties of polymers.

[0004] Polypropylene is a thermoplastic resin with excellent properties. Carbon fiber reinforced polypropylene composites can play a unique role in meeting the needs of automotive lightweighting. Short-cut carbon fiber reinforced materials with high tensile strength, high tensile modulus, and high impact strength remain a technical problem that urgently needs to be solved in this field.

[0005] Existing technologies improve the compatibility between polypropylene resin and carbon fiber by adding maleic anhydride-grafted polypropylene, maleic anhydride-grafted POE, ethylene-butyl acrylate-grafted maleic anhydride, ethylene-butyl acrylate-grafted glycidyl methacrylate, epoxy resin, etc., to polypropylene and carbon fiber composites. However, this only addresses the rigidity issue in continuous carbon fiber reinforced materials; a solution remains elusive for improving the impact strength of short-cut carbon fiber reinforced polypropylene materials. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of existing polypropylene and carbon fiber composite materials, which have poor compatibility and cannot significantly improve the impact performance of the material while maintaining the mechanical properties of the material. The present invention provides a polypropylene composite material that can significantly improve the impact performance of the material while maintaining the mechanical properties of the material, and enables the material to have high tensile strength, high tensile modulus and high impact strength at the same time.

[0007] Another object of the present invention is to provide a method for preparing a polypropylene composite material.

[0008] Another object of the present invention is to provide an application of polypropylene composite material in the preparation of automotive interior or exterior trim.

[0009] The above-mentioned objective of this invention is achieved through the following technical solution:

[0010] A polypropylene composite material, comprising the following components by weight:

[0011]

[0012]

[0013] The polar graft A is a maleic anhydride graft, and the mass grafting rate of maleic anhydride is 0.7% to 1.3%. The mass grafting rate of maleic anhydride is tested by acid-base titration, and the test conditions are titration with KOH-ethanol solution at 75°C.

[0014] Polar graft B is a glycidyl methacrylate (GMA) graft, with a mass grafting rate of 0.6-0.8% for GMA. The mass grafting rate of GMA was determined by FTIR under potassium bromide pelleting conditions, and the area of ​​the characteristic peak of the epoxy was calculated.

[0015] This invention uses maleic anhydride grafts and GMA grafts as compatibilizers in glass fiber reinforced polypropylene, which improves the material's impact resistance while maintaining its mechanical strength at room temperature. This is because the polar structures in maleic anhydride and GMA effectively coat the carbon fiber surface, enhancing the material's interfacial strength, while the epoxy groups and carboxyl groups react to form an interpenetrating network, maintaining the material's high stiffness and toughness.

[0016] Preferably, the weight ratio of the polar graft B to the polar graft A is 0.6 to 1.

[0017] Preferably, the polar graft A is one or more of maleic anhydride-grafted polypropylene and maleic anhydride-grafted polyethylene.

[0018] More preferably, the polar graft A is maleic anhydride-grafted polypropylene.

[0019] Preferably, the polar graft B is one or more of glycidyl methacrylate-grafted polyolefin elastomer and glycidyl methacrylate-grafted polypropylene.

[0020] More preferably, the polar graft B is a glycidyl methacrylate-grafted polyolefin elastomer.

[0021] Optionally, the average length of the chopped carbon fibers is 2.5-11 mm.

[0022] Preferably, the average length of the chopped carbon fibers is 3.0-9.0 mm.

[0023] The average length of chopped carbon fibers affects the final tensile strength of the material.

[0024] β-nucleating agents facilitate the formation of β-crystals in polypropylene resin, resulting in smaller crystal sizes and more uniform structures in polypropylene, thereby improving the material's rigidity-toughness balance.

[0025] Preferably, the β-nucleating agent is one or more of aryldimethylamide, calcium pimecrolate, or calcium octanoate.

[0026] More preferably, the β-nucleating agent is aryldimethylamide.

[0027] Optionally, the melt flow rate of the polypropylene resin is 10-150 g / 10 min, the test standard is GB / T 3682.1-2018, and the test conditions are 230℃ and 2.16 kg.

[0028] Preferably, the melt flow rate of the polypropylene resin is 30-100 g / 10 min, the test standard is GB / T 3682.1-2018, and the test conditions are 230℃ and 2.16 kg.

[0029] Optionally, the polypropylene resin is homopolymer polypropylene and / or copolymer polypropylene.

[0030] Preferably, the polypropylene resin is homopolymer polypropylene.

[0031] Preferably, the antioxidant is one or more of hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants.

[0032] Optionally, the hindered phenolic antioxidant is one or more of antioxidants 1010, 1976, or 3114.

[0033] Optionally, the phosphite antioxidant is one or more of antioxidants 168, 626, or PEP-36.

[0034] Optionally, the weight ratio of hindered phenolic antioxidants to phosphite antioxidants is 1:1.

[0035] Antioxidants can enhance the antioxidant effect of polypropylene composites.

[0036] The present invention also protects a method for preparing polypropylene composite material, comprising the following steps: mixing the components, melting and extruding them through an extruder, granulating them, and drying them to obtain the polypropylene composite material.

[0037] Preferably, the preparation method of polypropylene composite material includes the following steps: mixing all components except chopped carbon fibers, feeding them into a twin-screw extruder from the main feed port of the extruder, feeding the chopped carbon fibers into the extruder from the side feed port of the extruder, and obtaining the polypropylene composite material after melt extrusion, granulation, and drying.

[0038] The extruder can be a twin-screw extruder.

[0039] The polypropylene composite material of the present invention can be prepared by the following steps:

[0040] S1. Weigh the polypropylene resin, polar graft A, polar graft B, antioxidant and nucleating agent according to the mass parts and add them to the high-speed mixer for mixing. Then add them to the twin-screw extruder with a length-to-diameter ratio of 40:1 for melt mixing and dispersion. After plasticizing by the twin-screw extruder, the temperature of the twin-screw extruder is set to 180℃~200℃ and the screw speed is 400~450 rpm.

[0041] S2. Short carbon fibers are fed into the side feed port of the twin-screw extruder. The temperature of the barrel at the side feed port is set to 180℃~200℃. After traction, cooling, pelletizing and drying, polypropylene composite material is obtained.

[0042] The polypropylene composite material prepared by this invention has high tensile strength, high tensile modulus and high impact strength, and can be widely used in the preparation of plastic products. This invention particularly protects the application of the polypropylene composite material in the preparation of automotive parts, especially automotive interior and / or automotive exterior parts.

[0043] The interior of a car can be one or more of the following: dashboard frame, center console, or door panel brackets.

[0044] Automotive exterior trim can be one or more of the following: bumper brackets, dashboard crossbeams (CCB), or underbody protection panels.

[0045] An automotive component is manufactured by injection molding from any of the polypropylene composite materials described above.

[0046] Preferably, the automotive component is an interior / exterior trim part.

[0047] The automotive interior components include door panels, door lock brackets, or bumper brackets, etc.

[0048] Compared with the prior art, the beneficial effects of the present invention are:

[0049] The polypropylene composite material of the present invention includes polypropylene resin; chopped carbon fibers; polar graft A; polar graft B; β-nucleating agent; and antioxidant. Through the synergistic effect of adding specific polar graft A and polar graft B, the interfacial compatibility between polypropylene and carbon fibers in the polypropylene composite material is effectively improved. This significantly enhances the impact performance of the material while maintaining its mechanical properties, enabling the material to simultaneously possess high tensile strength, high tensile modulus, and high impact strength.

[0050] The polypropylene composite material of the present invention has a tensile strength ≥108 MPa, a tensile modulus ≥10300 MPa, and an impact strength ≥9.6 kJ / m. 2 . Detailed Implementation

[0051] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0052] The raw materials used in the various embodiments and comparative examples of the present invention are shown in Table 1 below.

[0053] Table 1

[0054]

[0055]

[0056] The preparation method of polar graft B3 is as follows: 1.5% GMA, 0.2% styrene, 98.3% POE 7467 and initiator by mass percentage are mixed evenly, added to a twin-screw extruder for extrusion, pelleting, and drying for later use. The extrusion temperature is 160℃.

[0057] The polar graft B4 is prepared by mixing 0.7% GMA, 0.2% styrene, 99.1% POE 7467 and an initiator by mass percentage, adding the mixture to a twin-screw extruder for extrusion, pelleting, and drying. The extrusion temperature is 160℃.

[0058] The polar graft B5 is prepared by mixing 0.8% GMA, 0.2% styrene, 99% POE7467 and an initiator by mass percentage, adding the mixture to a twin-screw extruder for extrusion, pelleting, and drying. The extrusion temperature is 160℃.

[0059] Examples 1-21

[0060] A polypropylene composite material, prepared by weight, is composed of the following components: polypropylene resin; chopped carbon fibers; polar graft A; polar graft B; β-nucleating agent; and antioxidant.

[0061] The specific content of each component is shown in Table 2 below.

[0062] Table 2. Composition of polypropylene composite materials in each embodiment (parts by weight)

[0063] Components 1 2 3 4 5 Polypropylene resin 1 62.3 80 50.3 62.3 62.3 Short-cut carbon fiber 1 30 20 40 30 30 Polar graft A1 4 3 5 4.5 3.6 Polar graft B1 3.2 2.4 4 2.7 3.6 β-nucleating agent 1 0.1 0.1 0.1 0.1 0.1 antioxidants 0.4 0.4 0.4 0.4 0.4

[0064] Continued from Table 2

[0065]

[0066]

[0067] Continued from Table 2

[0068] Components 17 18 19 20 21 Polypropylene resin 1 62.3 62.3 62.3 62.3 62.3 Short-cut carbon fiber 1 30 30 30 30 30 Polar graft A1 4 4 4 4 Polar graft A6 4 Polar graft B1 3.2 3.2 Polar graft B2 3.2 Polar graft B5 3.2 Polar graft B6 3.2 β-nucleating agent 1 0.1 0.1 0.1 0.1 β-nucleating agent 2 0.1 antioxidants 0.4 0.4 0.4 0.4 0.4

[0069] The preparation method of the polypropylene composite material described above includes the following steps:

[0070] S1. Weigh the polypropylene resin, polar graft A, polar graft B, antioxidant and nucleating agent according to the mass parts and add them to the high-speed mixer and mix for 5 minutes. Then add them to the twin-screw extruder with a length-to-diameter ratio of 40:1 for melt mixing and dispersion. After plasticizing by the twin-screw extruder, the screw speed is 450 rpm.

[0071] S2. Short carbon fibers are fed into the side feed port of a twin-screw extruder. The temperature of the side feed port barrel is set to 180℃. After traction, cooling, pelletizing and drying, polypropylene composite material is obtained.

[0072] The processing temperatures from the feed inlet to the die head are: 100℃, 180℃, 180℃, 200℃, 200℃, 200℃, 200℃, 180℃, 200℃, 200℃.

[0073] Comparative Examples 1-12

[0074] A polypropylene composite material, by weight, comprises the following components: polypropylene resin; chopped carbon fibers; polar graft A; polar graft B; β-nucleating agent; and antioxidant.

[0075] The specific content of each component is shown in Table 3 below.

[0076] Table 3. Composition of polypropylene composite materials in each comparative example (parts by weight)

[0077] Components 1 2 3 4 5 6 7 8 9 10 11 12 Polypropylene resin 1 69.5 62.3 62.3 62.3 62.3 62.3 62.3 62.3 62.3 62.3 62.3 62.3 Short-cut carbon fiber 1 30 30 30 30 30 30 30 30 30 30 30 30 Polar graft A1 0 0 7 7.2 4 4 4 4 4 4 Polar graft A3 4 Polar graft A4 4 Polar graft B1 0 7.2 3.2 0 6 3.2 3.2 3.2 3.2 3.2 Polar graft B3 3.2 Polar graft B4 3.2 β-nucleating agent 1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0 0.4 α nucleating agent 0.1 antioxidants 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4

[0078] The preparation method of the polypropylene composite material described above is the same as that in the examples, and will not be repeated here.

[0079] Result detection

[0080] The polypropylene composite materials of each embodiment and comparative example were tested according to the following method:

[0081] (1) Tensile strength: according to ISO 527-2016 method, tensile speed 10 mm / min.

[0082] (2) Tensile modulus: according to ISO 527-2016 method, tensile speed 1 mm / min.

[0083] (3) Impact performance: According to ISO 179-2016 method, 4 mm thick specimens with notch type A, pendulum impact capacity is 4.5J.

[0084] The specific test results of the polypropylene composite materials of each embodiment are shown in Table 4 below:

[0085] Table 4

[0086] Example Tensile strength / MPa Tensile modulus / MPa <![CDATA[Impact strength / kJ / m 2 > 1# 122 13500 12 2# 108 10500 10 3# 131 17000 10 4# 119 12000 11 5# 120 12800 11 6# 120 12700 11 7# 118 12500 9.6 8# 110 10400 11 9# 115 11600 11 10# 108 11800 12 11# 116 12900 12 12# 112 12300 12 13# 110 10300 10 14# 111 11600 10 15# 118 12800 11 16# 118 12700 11 17# 110 12000 10 18# 118 12700 11 19# 117 12600 11 20# 116 12400 9.8 21# 119 12700 10

[0087] The specific test results of the polypropylene composite materials of each comparative example are shown in Table 5 below: Table 5

[0088]

[0089]

[0090] As can be seen from the above data, the polypropylene composite material of the present invention, through the synergistic effect of adding specific polar grafts A and B, effectively improves the interfacial compatibility between polypropylene and carbon fibers in the polypropylene composite material. While maintaining the mechanical properties of the material, it significantly enhances the impact resistance, enabling the material to simultaneously possess high tensile strength, high tensile modulus, and high impact strength. The polypropylene composite material of the present invention has a tensile strength ≥ 108 MPa, a tensile modulus ≥ 10300 MPa, and an impact strength ≥ 9.6 kJ / m. 2 .

[0091] As can be seen from Comparative Example 1, without the addition of polar graft A and polar graft B, the tensile strength and tensile modulus of the material are significantly too low.

[0092] As can be seen from Comparative Example 2, the impact strength of the material is too low without the addition of polar graft A.

[0093] As can be seen from Comparative Example 3, if too much polar graft A is added, the impact strength will also fail to meet the requirements.

[0094] As can be seen from Comparative Example 4, the impact strength of the material was not improved without the addition of polar graft B.

[0095] As can be seen from Comparative Example 5, if too much polar graft B is added, the impact strength will not meet the requirements due to the high elastomer content in the graft.

[0096] Comparative Examples 6 and 7 show that both excessively high and low grafting rates of maleic anhydride in polar graft A will reduce the tensile strength of carbon fiber reinforced polypropylene. If the grafting rate of maleic anhydride is too low, it is difficult to ensure interfacial bonding between polar graft A and chopped carbon fibers. If the grafting rate of maleic anhydride is too high, it is detrimental to bonding with the polypropylene resin matrix and also hinders the improvement of tensile strength.

[0097] Comparative Examples 8 and 9 show that in polar graft B, if the glycidyl methacrylate grafting rate is too high or too low, the impact strength of the material is not improved.

[0098] Comparative Examples 10 and 11 show that neither adding β-nucleating agent nor adding too much will reduce the impact strength.

[0099] As can be seen from Comparative Example 12, the use of α nucleating agents leads to an increase in the crystallinity of the material, but the α crystal form is not conducive to the impact strength of the material.

[0100] As can be seen from Examples 1, 4 and 5, when the weight ratio of the polar graft B to the polar graft A is 0.6 to 1, it is more conducive to the formation of a good synergistic effect between the polar grafts, which is beneficial to the improvement of strength and impact.

[0101] As can be seen from Examples 1, 6 to 10, the melt flow rate of polypropylene resin mainly affects the tensile strength properties of the material, and a suitable flow rate can achieve good tensile strength.

[0102] The polypropylene resin is a homopolymer polypropylene resin, which is more conducive to tensile strength.

[0103] As can be seen from Examples 1, 11 to 14,

[0104] The length of chopped carbon fibers mainly affects the tensile strength of the material. The longer the length, the higher the tensile strength. However, excessive length can cause dispersion problems and reduce tensile strength.

[0105] As can be seen from Examples 1, 15-16, Comparative Example 6 and Comparative Example 7, the mass grafting rate of polar graft A affects the tensile strength of the material, and a suitable grafting rate is an important guarantee for improving interface properties.

[0106] As can be seen from Examples 1 and 17, maleic anhydride-grafted polypropylene is more beneficial for tensile strength in polar graft A.

[0107] As can be seen from Examples 1 and 20, in polar graft B, polar graft B being glycidyl methacrylate grafted polyolefin elastomer is more beneficial to impact strength.

[0108] As can be seen from Examples 1 and 21, when the nucleating agent is aryldimethylamide β nucleating agent, it is more conducive to improving the impact strength of the material.

[0109] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A polypropylene composite, characterized in that, By weight parts, including the following components: Polypropylene resin 50-80 parts; Short carbon fiber 20-40 parts; Polar graft A 3-5 parts; Polar graft B 2-5 parts; Beta nucleating agent 0.05-0.3 parts; Antioxidant 0.2-2 parts; Among them, the polar graft A is maleic anhydride graft, the mass grafting rate of maleic anhydride is 0.7-1.3%; The polar graft B is glycidyl methacrylate grafted polyolefin elastomer, the mass grafting rate of glycidyl methacrylate is 0.6-0.8%; The weight ratio of the polar graft B and the polar graft A is (3.2 / 4)~1.

2. The polypropylene composite of claim 1, wherein The polar graft A is one or several of maleic anhydride grafted polypropylene, maleic anhydride grafted polyethylene.

3. The polypropylene composite of claim 1, wherein the polypropylene is a homopolymer of propylene. The average length of the short carbon fiber is 2.5-11mm.

4. The polypropylene composite of claim 1, wherein the polypropylene is a homopolymer of propylene. The beta nucleating agent is one or several of aryl dimethyl amide, calcium heptanoate or calcium octanoate.

5. The polypropylene composite of claim 1, wherein the polypropylene is a homopolymer of propylene. The melt mass flow rate of the polypropylene resin is 10-150g / 10min, the test standard is GB / T 3682.1-2018, and the test condition is 230℃, 2.16kg.

6. The polypropylene composite of claim 1, wherein the polypropylene is present in an amount of from about 50 to about 95 weight percent. The antioxidant is one or several of hindered phenolic antioxidant, phosphite antioxidant or thioester antioxidant.

7. Process for the production of the polypropylene composite material according to any one of claims 1 to 6, characterized in that, Including the following steps: mixing each component except short carbon fiber, adding double screw extruder from the main feeding port of extruder, adding short carbon fiber from the side feeding port of extruder into extruder, melting extrusion, granulation, drying, and then the polypropylene composite material is obtained.

8. The application of the polypropylene composite material in any one of claims 1-6 in preparing automotive interior or automotive exterior materials.

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