A polypropylene composite material, its preparation method and application

Abstract

The present invention discloses a polypropylene composite material, a preparation method thereof and an application. The polypropylene composite material of the present invention comprises the following components: polypropylene resin, carbon black, hollow glass microspheres, compatibilizer, antioxidant; the polypropylene resin adopts the ISO 1133-1-2011 standard, and at 190 °C and 2.16 kg, the melt index is measured to be 60-90 g / 10 min; the specific surface area of the carbon black is 70-100 g / m 2 ; the density of the hollow glass microspheres is 0.3-0.4 g / m 3 , and the average particle size is 30-45 μm. By selecting polypropylene with a specific melt index, combining it with carbon black having a specific specific surface area and specific hollow glass microspheres, the carbon black is uniformly dispersed in the resin matrix to form a conductive network, and at the same time, the hollow glass microspheres are used to reduce the thermal conductivity of the composite material. The synergistic effect of the three enables the polypropylene composite material to have both high conductivity and high anti-aging performance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer compound compositions, and more specifically, to a polypropylene composite material. Background Art

[0002] The development of new energy vehicles is getting faster and faster, and with the development of intelligence, many functional parts are added to passenger cars accordingly, such as more and more radars and controllers. Some radar shells and controller shells require materials with certain electrical conductivity. Compared with other general thermoplastic resins, polypropylene materials are widely used in automotive decorative parts because of their advantages such as low relative density, low price, good processing performance and good comprehensive performance.

[0003] For example, the prior art discloses a conductive polypropylene composite material and a preparation method thereof, wherein the raw material components are composed of the following proportions by weight: 65% to 86% polypropylene resin, 10% to 25% superconductive carbon black, 2% to 3% alumina, 1.2% to 1.5% graphite powder, 0.1% to 0.4% thermal stabilizer, 0.1% to 0.4% antioxidant, and 0.5% to 1.5% compatibilizer. Superconductive carbon black is used to improve the conductive properties of the polypropylene composite material, but the conductivity of the polypropylene composite material is low and the aging resistance is poor. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects and shortcomings of the existing conductive polypropylene composite materials, such as low conductivity and poor aging resistance, and to provide a polypropylene composite material. By selecting polypropylene with a specific melt index, combining it with carbon black with a specific specific surface area and specific hollow glass microbeads, the carbon black is uniformly dispersed in a resin matrix to form a conductive network, and the hollow glass microbeads are used to reduce the thermal conductivity of the composite material. The three act synergistically, so that the polypropylene composite material has both high conductivity and high aging resistance.

[0005] Another object of the present invention is to provide a method for preparing a polypropylene composite material.

[0006] Another object of the present invention is to provide use of the polypropylene composite material in preparing a radar bracket or a controller shell.

[0007] The invention provides a vehicle radar reflection bracket made of the polypropylene composite material.

[0008] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0009] A polypropylene composite material, comprising the following components by weight:

[0010] Polypropylene resin 55.4-63.6 parts;

[0011] 18 - 22 parts of carbon black;

[0012] 18 - 22 parts of hollow glass microspheres;

[0013] The polypropylene resin adopts the ISO 1133 - 1 - 2011 standard and has a melt index of 60 - 90 g / 10 min measured at 190 °C and 2.16 kg;

[0014] The specific surface area of the carbon black is 70 - 100 m 2 / g;

[0015] The density of the hollow glass microspheres is 0.3 - 0.4 g / m 3 , and the average particle size is 30 - 45 μm.

[0016] In the present invention, by selecting polypropylene with a specific melt index and combining it with carbon black having a specific specific surface area and specific hollow glass microspheres, the carbon black is uniformly dispersed in the resin matrix to form a conductive network. At the same time, the hollow glass microspheres are used to reduce the thermal conductivity of the composite material. The synergistic effect of the three makes the polypropylene composite material have both high conductivity and high aging resistance. The inventor found through a large number of studies that when the melt index of the polypropylene resin is 60 - 90 g / 10 min, it is beneficial to promote the uniform dispersion of carbon black and hollow glass microspheres in the resin matrix. When the melt index of the polypropylene resin is too high or too low, the dispersion of carbon black and hollow glass microspheres becomes poor, and it is difficult to form an effective conductive network, thereby affecting the conductive performance and heat - aging resistance of the polypropylene composite material. The main role of carbon black is to improve the conductive performance of the polypropylene composite material. It is also found that when the specific surface area of carbon black is too small, it is difficult to form a conductive network in the resin matrix, resulting in a decrease in conductive performance. When the surface area of carbon black is too large, not only will the carbon black be difficult to disperse, reducing the conductive performance, but also the contact area between carbon black and polypropylene resin will be too large, resulting in a significant decrease in the aging resistance of the polypropylene composite material.

[0017] The addition of hollow glass microspheres can effectively solve the problem of too high thermal conductivity brought by carbon black, thereby improving the aging resistance of the polypropylene composite material. At the same time, through a large number of studies, it is found that the particle size and density of hollow glass microspheres play a key role in improving the aging resistance of the composite material. When the particle size of the hollow glass microspheres is too large, it is difficult to form an effective heat - insulation network, increasing the thermal conductivity of the composite material and decreasing the aging resistance. When the particle size is too small, it is not easy to disperse, which will also affect the aging performance of the polypropylene composite material. Under the same particle size condition, if the density of the hollow glass microspheres is too large, it means that the wall thickness of the hollow glass microspheres is too large, and the thermal conductivity of glass itself is higher than that of air, which will reduce the aging resistance of the composite material. If the density is too small, it means that its wall thickness is too small, and it is easy to break during the processing, unable to play a role.

[0018] The specific surface area of the carbon black described above was tested according to the ISO 9277-2010 standard, the density of the hollow glass microspheres was tested according to the ISO1183 standard, and the particle size of the hollow glass microspheres was obtained by detection with an electron microscope.

[0019] Preferably, the mass ratio of the carbon black to the hollow glass microspheres is 1:(1 to 1.2).

[0020] When the mass ratio of the carbon black to the hollow glass microspheres is 1:(1 to 1.2), while ensuring the good electrical conductivity of the polypropylene composite material, it can ensure that it has a relatively low thermal conductivity at the same time, thereby significantly improving the heat aging performance of the polypropylene composite material.

[0021] Preferably, the polypropylene composite material further comprises a compatibilizer and an antioxidant.

[0022] Specifically, by weight, the polypropylene composite material further comprises 4 to 6 parts of a compatibilizer and 0.4 to 0.6 parts of an antioxidant.

[0023] Specifically, the compatibilizer is one or more of maleic anhydride grafted polypropylene, glycidyl methacrylate grafted polypropylene, or ethylene-methyl acrylate-glycidyl methacrylate copolymer.

[0024] Specifically, the antioxidant is a hindered phenol antioxidant and / or a phosphite antioxidant.

[0025] The present invention also protects a preparation method of the above polypropylene composite material, comprising the following steps:

[0026] Add the polypropylene resin, carbon black, hollow glass microspheres, compatibilizer, and antioxidant into a twin-screw extruder, mix evenly and then melt and extrude into pellets to obtain the polyester composition.

[0027] Specifically, the temperature of the melt extrusion is 200 to 230 °C, and the temperature settings of the first to ninth zones of the screw of the twin-screw extruder are as follows: the temperature of the first zone is 175-185 °C, the temperature of the second zone is 190-200 °C, the temperature of the third zone is 190-200 °C, the temperature of the fourth zone is 190-200 °C, the temperature of the fifth zone is 190-200 °C, the temperature of the sixth zone is 190-200 °C, the temperature of the seventh zone is 185-195 °C, the temperature of the eighth zone is 185-195 °C, the temperature of the ninth zone is 180-190 °C, and the main machine speed is 170-190 r / min.

[0028] An application of the above polypropylene composite material in the preparation of a radar bracket or a controller housing is also within the protection scope of the present invention.

[0029] The present invention also protects a vehicle radar reflection bracket prepared from the above polypropylene composite material.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] The present invention provides a polypropylene composite material. By selecting polypropylene with a specific melt index, combining it with carbon black having a specific specific surface area and specific hollow glass microspheres, the carbon black is uniformly dispersed in the resin matrix to form a conductive network. At the same time, the hollow glass microspheres are used to reduce the thermal conductivity of the composite material. The synergistic effect of the three enables the polypropylene composite material to have both high electrical conductivity and high anti-aging performance. Specific Embodiments

[0032] The present invention will be further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw material reagents used in the embodiments of the present invention are conventional raw material reagents purchased.

[0033] 1. Raw Material Reagents

[0034] Polypropylene Resin 1: Measured by the ISO 1133-1-2011 standard, the melt index is 80 g / 10 min at 190 °C and 2.16 kg, grade 7945, manufacturer ExxonMobil;

[0035] Polypropylene Resin 2: Measured by the ISO 1133-1-2011 standard, the melt index is 60 g / 10 min at 190 °C and 2.16 kg, grade M60RHC, manufacturer Sinopec;

[0036] Polypropylene Resin 3: Measured by the ISO 1133-1-2011 standard, the melt index is 90 g / 10 min at 190 °C and 2.16 kg, grade K7100, manufacturer Sinopec;

[0037] Polypropylene Resin 4: Measured by the ISO 1133-1-2011 standard, the melt index is 30 g / 10 min at 190 °C and 2.16 kg, grade EP548R, manufacturer CNOOC and Shell;

[0038] Polypropylene Resin 5: Measured by the ISO 1133-1-2011 standard, the melt index is 100 g / 10 min at 190 °C and 2.16 kg, grade M100RHC, manufacturer Sinopec;

[0039] Carbon Black 1: Specific surface area is 91 g / m 2 , grade PFEB, manufacturer Columbian;

[0040] Carbon Black 2: Specific surface area is 71 g / m 2 , grade 880R, manufacturer Cabot;

[0041] Carbon black 3: Specific surface area is 98 g / m 2 , grade R1300, manufacturer Cabot;

[0042] Carbon black 4: Specific surface area is 42 g / m 2 , grade C7054, manufacturer Columbian;

[0043] Carbon black 5: Specific surface area is 180 g / m 2 , grade R2350, manufacturer Columbian;

[0044] Hollow glass microsphere 1: Density is 0.35 g / m 3 , average particle size is 40 μm, grade S35, manufacturer 3M;

[0045] Hollow glass microsphere 2: Density is 0.40 g / m 3 , average particle size is 45 μm, grade K37, manufacturer 3M;

[0046] Hollow glass microsphere 3: Density is 0.30 g / m 3 , average particle size is 30 μm, grade S28HS, manufacturer 3M;

[0047] Hollow glass microsphere 4: Density is 0.20 g / m 3 , average particle size is 60 μm, grade K20, manufacturer 3M;

[0048] Hollow glass microsphere 5: Density is 0.46 g / m 3 , average particle size is 20 μm, grade iM16K, manufacturer 3M;

[0049] Hollow glass microsphere 6: Density is 0.22 g / m 3 , average particle size is 35 μm, grade S22, manufacturer 3M;

[0050] Compatibilizer: Maleic anhydride grafted polypropylene, grade CA100, manufacturer Arkema;

[0051] Antioxidant: Composed of a hindered phenol antioxidant and a phosphite antioxidant compounded in a mass ratio of 1:1. Both the hindered phenol antioxidant and the phosphite antioxidant are commercially available, and the same kind is used in other parallel experiments.

[0052] 2. The high heat-resistant and high-conductive polypropylene composites of each example and comparative example of the present invention are prepared by the following preparation method:

[0053] Weigh each component according to the formula, mix them evenly, then add them into a twin-screw extruder for melt blending and extrusion granulation, thus obtaining the high heat-resistant and high-conductive polypropylene composite;

[0054] Among them, the conditions for melt extrusion by the twin-screw extruder are as follows: the temperature of zone 1 is 175 - 185 °C, the temperature of zone 2 is 190 - 200 °C, the temperature of zone 3 is 190 - 200 °C, the temperature of zone 4 is 190 - 200 °C, the temperature of zone 5 is 190 - 200 °C, the temperature of zone 6 is 190 - 200 °C, the temperature of zone 7 is 185 - 195 °C, the temperature of zone 8 is 185 - 195 °C, the temperature of zone 9 is 180 - 190 °C, and the main machine speed is 170 - 190 r / min.

[0055] 3. Performance Testing

[0056] (1) Surface resistivity, test standard ISO14309 - 2011;

[0057] (2) Thermal aging performance, test standard ISO 188 - 2011, test temperature 150 °C;

[0058] Examples 1 - 12

[0059] The weight parts of each component of the polypropylene composite material in Examples 1 - 12 are shown in Table 1, where X is the mass ratio of carbon black to hollow glass microspheres.

[0060] Table 1 Polypropylene Composite Materials in Examples 1 - 12

[0061]

[0062] Comparative Examples 1 - 11

[0063] The weight parts of each component of the polypropylene composite material in Comparative Examples 1 - 11 are shown in Table 2, where X is the mass ratio of carbon black to hollow glass microspheres.

[0064] Table 2 Polypropylene Composite Materials in Comparative Examples 1 - 11

[0065]

[0066]

[0067] The performance test results of the polypropylene composite materials in each example and comparative example according to the method mentioned above are shown in Table 3.

[0068] Table 3 Test Results of Each Example and Comparative Example

[0069]

[0070]

[0071] It can be seen from the data in Table 3 that the high heat-resistant and high-conductive polypropylene composite material of the present invention has both high conductivity and high aging resistance. While ensuring that its conductivity reaches 10 4 ~10 6while the surface resistance is Ω / sq, the thermal aging time reaches 450 - 520 h.

[0072] It can be seen from Comparative Example 1 and Comparative Example 2 that when the addition amount of hollow glass microspheres is too small, although it is beneficial to improve the electrical conductivity of the polypropylene composite material, it will also cause a sharp decline in its heat aging resistance; when the addition amount of hollow glass microspheres is too large, it is difficult to form an effective conductive network, resulting in a significant decrease in the electrical conductivity of the polypropylene composite material.

[0073] It can be found from Comparative Example 3 and Comparative Example 4 that when the addition amount of carbon black is too small, the electrical conductivity of the polypropylene composite material will decrease significantly; when the addition amount of carbon black is too large, the thermal conductivity coefficient of the polypropylene composite material will increase significantly, thereby reducing the aging resistance of the polypropylene composite material.

[0074] It can be seen from Comparative Example 5, Comparative Example 6 and Comparative Example 7 that when the particle size of the hollow glass microspheres is too large or too small, it is difficult to form an effective heat insulation network, resulting in an increase in the thermal conductivity coefficient of the polypropylene composite material and a significant decrease in the aging resistance; at the same time, it can also be found that even if the particle size of the hollow glass microspheres is appropriate, when its density is too small, it is easy to cause the hollow microspheres to break, unable to play a heat insulation role, and also unable to effectively improve the aging resistance of the polypropylene composite material.

[0075] It can be found from Comparative Example 8 and Comparative Example 9 that when the specific surface area of carbon black is too large, the contact area between carbon black and polypropylene resin is too large, resulting in a significant decrease in the aging resistance of the polypropylene composite material. At the same time, due to the reduction of its dispersion uniformity, the electrical conductivity of the polypropylene composite material will be affected; when the specific surface area of carbon black is too small, it is difficult for carbon black to form a conductive network in the resin matrix, resulting in poor electrical conductivity.

[0076] It can be seen from Comparative Example 10 and Comparative Example 11 that when the melt index of the polypropylene resin is too large or too small, the dispersion uniformity of carbon black and hollow glass microspheres in the polypropylene resin will be affected, thereby deteriorating the electrical conductivity and heat aging resistance of the polypropylene composite material.

[0077] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A polypropylene composite material, characterized in that, by weight, it comprises the following components: 55.4 - 63.6 parts of polypropylene resin; 18 - 22 parts of carbon black; 18 - 22 parts of hollow glass microspheres; The polypropylene resin adopts the ISO 1133-1-2011 standard, and at 190 °C and 2.16 kg, its melt index is measured to be 60 - 90 g / 10 min; The specific surface area of the carbon black is 70 to 100 g / m 2 ; The density of the hollow glass microspheres is 0.3 to 0.4 g / m 3 , and the average particle size is 30 to 45 μm.

2. The polypropylene composite material according to claim 1, characterized in that, the mass ratio of the carbon black to the hollow glass microspheres is 1:(1 - 1.2).

3. The polypropylene composite material according to claim 1, characterized in that, the polypropylene composite material further comprises a compatibilizer and an antioxidant.

4. The polypropylene composite material according to claim 3, characterized in that, by weight, the polypropylene composite material further comprises 4 - 6 parts of compatibilizer and 0.4 - 0.6 parts of antioxidant.

5. The polypropylene composite material according to claim 3, characterized in that, the compatibilizer is one or more of maleic anhydride grafted polypropylene, glycidyl methacrylate grafted polypropylene or ethylene - methyl acrylate - glycidyl methacrylate copolymer.

6. The polypropylene composite material according to claim 3, characterized in that, the antioxidant is a hindered phenol antioxidant and / or a phosphite antioxidant.

7. A preparation method of the polypropylene composite material according to any one of claims 3 - 6, characterized in that, it comprises the following steps: Adding the polypropylene resin, carbon black, hollow glass microspheres, compatibilizer and antioxidant into an extruder, mixing and then melt - extruding and pelletizing to obtain the polypropylene composite material.

8. The polypropylene composite material according to claim 7, characterized in that, the temperature of the melt - extrusion is 200 - 230 °C.

9. An application of the polypropylene composite material according to any one of claims 1 - 6 in preparing a radar bracket or a controller housing.

10. A vehicle - mounted radar reflection bracket, characterized in that, the vehicle - mounted radar reflection bracket is prepared from the polypropylene composite material according to any one of claims 1 - 6.

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