阅读说明：本技术 一种低介电常数高耐候聚丙烯复合材料及其制备方法 (Low-dielectric-constant high-weather-resistance polypropylene composite material and preparation method thereof ) 是由 王清文 杨杰 刁雪峰 申应军 刘曙光 于 2021-08-19 设计创作，主要内容包括：本发明涉及高分子材料技术领域,特别涉及一种低介电常数高耐候聚丙烯复合材料及其制备方法。该聚丙烯复合材料包括以下组分：聚丙烯树脂、液晶高分子、相容剂、空心玻璃微珠、PTFE微粉、抗氧剂以及耐候助剂；按重量份计,所述聚丙烯树脂、液晶高分子、空心玻璃微珠与PTFE微粉的比值为(65～85)：(5～10)：(8～20)：(0.1～0.3)；所述耐候助剂为光稳定剂；按重量份计,所述抗氧剂与耐候助剂的比值为(0.4～0.8)：(0.1～0.3)。本发明提供的低介电常数高耐候聚丙烯复合材料兼具高强度、高耐候、低介电常数等优异性能,能够满足市场应用需求；其是一类非常适用于5G产品的材料,特别是5G基站天线罩等产品的应用。(The invention relates to the technical field of high polymer materials, in particular to a low-dielectric-constant high-weather-resistance polypropylene composite material and a preparation method thereof. The polypropylene composite material comprises the following components: polypropylene resin, liquid crystal polymer, compatilizer, hollow glass microsphere, PTFE micro powder, antioxidant and weather-resistant auxiliary agent; the ratio of the polypropylene resin, the liquid crystal polymer, the hollow glass beads and the PTFE micro powder is (65-85): (5-10): (8-20): (0.1 to 0.3); the weather-resistant auxiliary agent is a light stabilizer; the ratio of the antioxidant to the weather-resistant auxiliary agent is (0.4-0.8) in parts by weight: (0.1-0.3). The low-dielectric-constant high-weather-resistance polypropylene composite material provided by the invention has excellent performances of high strength, high weather resistance, low dielectric constant and the like, and can meet the market application requirements; the material is a material very suitable for 5G products, and is particularly suitable for products such as 5G base station antenna covers and the like.)

1. The polypropylene composite material with low dielectric constant and high weather resistance is characterized by comprising the following components: polypropylene resin, liquid crystal polymer, compatilizer, hollow glass microsphere, PTFE micro powder, antioxidant and weather-resistant auxiliary agent;

the ratio of the polypropylene resin, the liquid crystal polymer, the hollow glass beads and the PTFE micro powder is (65-85): (5-10): (8-20): (0.1 to 0.3);

the weather-resistant auxiliary agent is a light stabilizer; the ratio of the antioxidant to the weather-resistant auxiliary agent is (0.4-0.8) in parts by weight: (0.1-0.3).

2. The low dielectric constant high weather-resistant polypropylene composite material as claimed in claim 1, which comprises the following raw material components in parts by weight:

3. the low dielectric constant high weatherability polypropylene composite material according to claim 1, wherein the polypropylene resin is homopolypropylene.

4. The low dielectric constant high weather resistant polypropylene composite material as claimed in claim 3, wherein the melt flow rate of the polypropylene resin is (0.2-30) g/10 min.

5. The polypropylene composite material with low dielectric constant and high weather resistance as claimed in claim 4, wherein the liquid crystal polymer is a type III thermotropic liquid crystal polymer.

6. The low dielectric constant high weatherability polypropylene composite material according to claim 1, wherein the compatibilizer is one or more of polypropylene grafted maleic anhydride, polypropylene grafted glycidyl methacrylate.

7. The low dielectric constant high weatherability polypropylene composite material according to claim 1, wherein the antioxidant comprises 1,3,5, tris (3, 5-di-tert-butyl, 4-hydroxybenzyl) isocyanuric acid, pentaerythrityl tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], dioctadecyl thiodipropionate and tris [2, 4-di-tert-butylphenyl ] phosphite.

8. The low-dielectric-constant high-weatherability polypropylene composite material according to claim 7, wherein the mass ratio of 1,3,5, tris (3, 5-di-tert-butyl, 4-hydroxybenzyl) isocyanuric acid, pentaerythrityl tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], dioctadecyl thiodipropionate to tris [2, 4-di-tert-butylphenyl ] phosphite is 1:1:2: 1.

9. The low dielectric constant high weather resistant polypropylene composite material as claimed in claim 7 or 8, wherein the weather resistant auxiliary agent is one or more of light stabilizer 5585, light stabilizer 5589, light stabilizer 234 and light stabilizer 770.

10. A method for preparing the low dielectric constant high weatherability polypropylene composite material according to any one of claims 1-9, comprising the steps of:

s100, adding polypropylene resin, liquid crystal polymer, compatilizer, antioxidant, PTFE micro powder and weather-resistant auxiliary agent into a high-speed mixer, and uniformly mixing to obtain a mixture M;

s200, adding the mixture M into a double-screw extruder through a main feed, adding the hollow glass beads into the double-screw extruder through a side feed, and performing melt extrusion granulation in the double-screw extruder to obtain the polypropylene composite material.

Technical Field

The invention relates to the technical field of high polymer materials, in particular to a low-dielectric-constant high-weather-resistance polypropylene composite material and a preparation method thereof.

Background

Polypropylene (PP) is a thermoplastic synthetic material with excellent performance, and has wide application in the fields of automobiles, household electrical appliances, food packaging and medical treatment and health care. In order to enhance the mechanical strength of PP, in the prior art, a polar substance is usually added to modify the PP to generate a PP alloy with a wider application range, but the modification of the polar substance can cause the dielectric constant of the alloy material to be obviously increased, and cannot meet the requirements of industries requiring low dielectric materials, such as 5G communication industries and the like.

The liquid crystal polymer is a novel special engineering plastic, and molecules in a liquid crystal phase have a high-degree orientation structure under specific conditions, so that the material is endowed with excellent mechanical property and heat resistance, and therefore, the addition of the liquid crystal polymer to modify a PP material is a new idea and a new direction for preparing a novel modified PP alloy. However, the liquid crystal polymer and PP are incompatible systems, phase separation is easy to occur in the processing process, and the problem that the dielectric constant of PP alloy is obviously increased cannot be solved by adding the liquid crystal polymer conventionally.

The Chinese patent application with the application number of CN201710535349.9 and the publication date of 2019, 01, 15 discloses a preparation method of a glass fiber reinforced polypropylene composite material, wherein the polypropylene composite material comprises the following components in parts by weight: 60-100 parts of polypropylene, 0-40 parts of glass fiber, 0-8 parts of interfacial compatilizer and 0-2 parts of coupling agent; the preparation method comprises the following steps: the polypropylene/glass fiber composite material is prepared by adding glass fiber, an interfacial compatilizer, a coupling agent and polypropylene and blending. The production process is simple, the rigidity of the polypropylene is effectively enhanced, the prepared material has higher strength, but the dielectric property of the polypropylene is not improved, and the weather resistance is not improved.

Therefore, the development of a polypropylene material with good mechanical properties and comprehensively improved dielectric properties, weather resistance and other properties is urgently needed in the market so as to meet the use requirements of the market.

Disclosure of Invention

In order to solve the problem that the traditional polypropylene material mentioned in the background art is difficult to simultaneously meet the performance requirements of high strength and low dielectric constant, the invention provides a low dielectric constant and high weather resistance polypropylene composite material, which is characterized by comprising the following components: polypropylene resin, liquid crystal polymer, compatilizer, hollow glass microsphere, PTFE micro powder, antioxidant and weather-resistant auxiliary agent; the ratio of the polypropylene resin, the liquid crystal polymer, the hollow glass beads and the PTFE micro powder is (65-85): (5-10): (8-20): (0.1 to 0.3); the weather-resistant auxiliary agent is a light stabilizer; the ratio of the antioxidant to the weather-resistant auxiliary agent is (0.4-0.8) in parts by weight: (0.1-0.3).

According to the invention, the raw material components of the liquid crystal polymer, the hollow glass beads and the PTFE micropowder are added to modify the polypropylene material, and the compatibility of the liquid crystal polymer and the surface of the polypropylene matrix resin is increased through the compatilizer, so that the bonding force between the polymers is enhanced, the polymers are enriched at the interface between the continuous phase PP and the disperse phase liquid crystal polymer, a good anchoring effect is achieved, the bonding degree of the continuous phase PP and the disperse phase liquid crystal polymer is enhanced, and the compatibility is greatly improved; according to the invention, the antioxidant and the weather-resistant auxiliary agent are compounded and used according to a certain proportion, and the liquid crystal polymer is synergistically matched with the high-efficiency antioxidant and the light stabilizing system (light stabilizer), so that the prepared polypropylene composite material has excellent weather resistance; the liquid crystal polymer has a self-reinforcing effect, the liquid crystal polymer is added with hollow glass beads and PTFE micro powder components, and the liquid crystal polymer, the hollow glass beads and the PTFE micro powder are matched according to a certain proportion, so that the excellent mechanical property and heat resistance of the liquid crystal polymer are utilized, the mechanical property and heat resistance of the material are obviously improved, and the liquid crystal polymer, the hollow glass beads and the PTFE micro powder are matched in a synergistic manner, so that the mechanical property, the heat resistance, the dielectric constant, the weather resistance and other properties of the material are comprehensively improved.

In one embodiment, the polypropylene resin is a homopolypropylene.

In one embodiment, the melt flow rate of the polypropylene resin is (0.2-30) g/10 min.

The preferable melt flow rate is (0.2-30) g/10min, when the melt flow rate is smaller than the range, the flowability of the homopolymerized polypropylene is insufficient, the flow speed is too low, and the processing processes of mixing, melting and extruding the polypropylene resin and other components are influenced, for example, the problems of uneven material distribution and the like are caused, so that the performance of the prepared polypropylene composite material is adversely influenced; similarly, when the melt flow rate is greater than the range, and the processing temperature reaches 250 ℃, the flow rate is high when the PP is molten, and the PP is too thin when the PP is molten, so that the mixing, melting and extrusion processing process of the polypropylene resin and other raw material components is influenced, and the performance of the prepared polypropylene composite material is adversely affected.

In one embodiment, the liquid crystal polymer is a type iii thermotropic liquid crystal polymer.

The type III thermotropic liquid crystal polymer is preferably selected, and because the processing temperature of the type III thermotropic liquid crystal polymer is lower than that of the type I thermotropic liquid crystal polymer and the type II thermotropic liquid crystal polymer, the type III thermotropic liquid crystal polymer can be melted at 230 ℃, so that the type III thermotropic liquid crystal polymer and the homopolymerized polypropylene with the melt flow rate of (0.2-30) g/10min can be well processed by matching, and the reason is that: the III type thermotropic liquid crystal polymer and the homopolymerized polypropylene with the melt flow rate of (0.2-30) g/10min are selected for blending, melting and extruding at a certain temperature, so that the III type thermotropic liquid crystal polymer can be ensured to have a molten form in the same processing temperature range, the homopolymerized polypropylene is ensured to have a proper flow rate, the III type thermotropic liquid crystal polymer and the homopolymerized polypropylene can be well processed, and the performance of the prepared polypropylene composite material is further improved.

In one embodiment, the compatibilizer is one or more of polypropylene grafted maleic anhydride and polypropylene grafted glycidyl methacrylate.

In one embodiment, the antioxidant comprises 1,3,5, tris (3, 5-di-tert-butyl, 4-hydroxybenzyl) isocyanuric acid, pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], dioctadecyl thiodipropionate, and tris [2, 4-di-tert-butylphenyl ] phosphite.

The preferable antioxidant compound combination comprises hindered phenol antioxidants with the melting point of 100-260 ℃:1, 3,5, tris (3, 5-di-tert-butyl, 4-hydroxybenzyl) isocyanuric acid and pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], a phosphite antioxidant with a melting point of greater than 160 ℃: tris [2, 4-di-tert-butylphenyl ] phosphite and thioester antioxidant: the dioctadecyl thiodipropionate and the antioxidant are compounded and combined in the polypropylene material to play a good synergistic effect and have more excellent oxidation resistance.

In one embodiment, the mass ratio of 1,3,5, tris (3, 5-di-tert-butyl, 4-hydroxybenzyl) isocyanuric acid, pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], dioctadecyl thiodipropionate to tris [2, 4-di-tert-butylphenyl ] phosphite is 1:1:2: 1.

In one embodiment, the weather resistant auxiliary is one or more of light stabilizer 5585, light stabilizer 5589, light stabilizer 234 and light stabilizer 770.

Preferably, the above light stabilizers, such as hindered amine light stabilizer 770, and the like, are used in combination with an antioxidant system comprising 1,3,5, tris (3, 5-di-tert-butyl, 4-hydroxybenzyl) isocyanurate, pentaerythrityl tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], dioctadecyl thiodipropionate, and tris [2, 4-di-tert-butylphenyl ] phosphite, the light stabilizer selected having a good synergistic effect with the above antioxidant system; in the polypropylene material, the heat resistance of the liquid crystal polymer is utilized to be cooperated with the high-efficiency antioxidant system and the light stabilizing system, so that the prepared polypropylene composite material has excellent weather resistance.

The invention also provides a preparation method of the low-dielectric-constant high-weather-resistance polypropylene composite material, which comprises the following steps:

s100, adding polypropylene resin, liquid crystal polymer, compatilizer, antioxidant, PTFE micro powder and weather-resistant auxiliary agent into a high-speed mixer, and uniformly mixing to obtain a mixture M;

s200, adding the mixture M into a double-screw extruder through a main feed, adding the hollow glass beads into the double-screw extruder through a side feed, and performing melt extrusion granulation in the double-screw extruder to obtain the polypropylene composite material.

Compared with the prior art, the invention has the following technical effects:

the low-dielectric-constant high-weather-resistance polypropylene composite material provided by the invention has excellent performances of high strength, high weather resistance, low dielectric constant and the like, and can meet the market application requirements; the material is a material very suitable for 5G products, and is particularly suitable for products such as 5G base station antenna covers and the like.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the following description will clearly and completely describe the embodiments of the present invention, and obviously, the described embodiments are a part of the embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a preparation method of a low-dielectric-constant high-weather-resistance polypropylene composite material, which comprises the following steps: s100, weighing the polypropylene resin, the liquid crystal polymer, the compatilizer, the antioxidant, the PTFE micro powder and the weather-resistant auxiliary agent according to a certain weight, adding the materials into a high-speed mixer, and mixing for 5-10 min to disperse and uniformly mix the raw material components to obtain a mixture M; s200, adding the mixture M into a double-screw extruder through a main feed, adding the hollow glass beads into the double-screw extruder through a side feed, wherein the temperature of each area of the double-screw extruder is 160-190 ℃, 190-220 ℃, 220-240 ℃, 230-250 ℃, the head temperature is 230-250 ℃, the length-diameter ratio of a screw of the double-screw extruder is 30-48, the rotating speed of the screw is (300-500) r/min, and the raw material components are melted, extruded and granulated in the double-screw extruder and then stay for 2-3 min to obtain the polypropylene composite material product.

The invention also provides the following examples and comparative examples:

the formulations (unit: parts by weight) of the examples and comparative examples provided by the present invention are shown in table 1 below:

TABLE 1

Wherein, the raw material components in the examples and comparative examples in table 1 are consistent in type selection, and the components are specifically: the hollow glass beads are IM30K produced by 3M company, and the particle size D90 of the hollow glass beads is 75 microns; the PTFE micropowder (also called low molecular weight polytetrafluoroethylene micropowder) is F202 produced by Furui science and technology Limited, which is powder with the particle size of 1-7 μm; the polypropylene resin is homo-polypropylene with the brand number of PPH-Y26 produced by the Ministry of Maoyi petrochemical company, and the melt flow rate is 25g/10min at 230 ℃ under the load of 2.16 kg; the liquid crystal polymer is a III type thermotropic liquid crystal polymer with A430 produced by American Seranies company; the compatilizer is PP-g-MAH (polypropylene grafted maleic anhydride); the antioxidant is prepared by compounding an antioxidant 3114(1,3,5, tri (3, 5-di-tert-butyl, 4-hydroxybenzyl) s-triazine), an antioxidant 1010 (tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester), an antioxidant DSTP (dioctadecyl thiodipropionate) and an antioxidant 168 (tri [2, 4-di-tert-butylphenyl ] phosphite) according to a mass ratio of 1:1:2: 1; the weather-resistant auxiliary agent is a light stabilizer 770 (bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate).

In addition to the practical choices embodied in the above specific embodiments, preferably, the polypropylene resin is homopolypropylene, and the melt flow rate parameter of the homopolypropylene may be in the range of 0.2-30 g/10min (190 ℃, 2.16kg), including but not limited to the practical choices embodied in the above embodiments;

in addition to the practical options presented in the specific examples above, the compatibilizer may preferably be PP-g-GMA (polypropylene grafted glycidyl methacrylate) or a combination of PP-g-GMA and PP-g-MAH, including but not limited to the practical options presented in the examples above;

in addition to the practical choices embodied in the above specific examples, preferably, the weather resistance auxiliary can be one or more of the combination of light stabilizer 5585, light stabilizer 5589, light stabilizer 234, and light stabilizer 770, including but not limited to the practical choices embodied in the above examples, wherein the above light stabilizer is an existing light stabilizer, light stabilizer 234 is also known as ultraviolet light absorber UV-234(2- (2-hydroxy-3 ',5' -dicumylphenyl) benzotriazole), light stabilizer 770 is also known as light stabilizer ZX-70 (bis-2, 2,6, 6-tetramethylpiperidinol sebacate), and the light stabilizer 5589 and light stabilizer 5585 can be molded using an existing light stabilizer produced by a new chemistry5589 and light stabilizer plastics5585；

In addition to the actual selection embodied in the above specific embodiment, the antioxidant may be prepared by compounding antioxidant 3114, antioxidant 1010, antioxidant DSTP and antioxidant 168 according to other mass ratios, and the mass ratio of antioxidant 3114, antioxidant 1010, antioxidant DSTP and antioxidant 168 adopted in the embodiment is preferably 1:1:2: 1.

According to the formulation shown in Table 1, the polyamide materials were prepared from the starting components of examples 1 to 3 and comparative examples 1 to 7 according to the following preparation method: (1) weighing the polypropylene resin, the liquid crystal polymer, the compatilizer, the antioxidant, the PTFE micro powder and the weather-resistant auxiliary agent according to a certain weight, putting the materials into a high-speed mixer, and mixing for 10min to disperse and uniformly mix the raw material components to obtain a mixture M; (2) and adding the mixture M into a double-screw extruder through a main feed, adding the hollow glass beads into the double-screw extruder through a side feed, performing melt extrusion granulation, and standing for 2.5min to obtain a product, thereby obtaining the polypropylene composite material, wherein the temperature of each zone of the double-screw extruder is 180 ℃, 200 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃ and the head temperature is 240 ℃ from 1 to 10 zones in sequence, the length-diameter ratio of a screw of the double-screw extruder is 42:1, and the rotating speed of the screw is 400 rpm. It should be noted that in the preparation method of example 8, the hollow glass microspheres were fed into the twin-screw extruder through the main feed, and the remaining preparation steps and conditions were identical to those of the above preparation method.

The polyamide materials obtained in the examples and comparative examples were tested for the relevant performance indexes under the same test conditions, and the test results are shown in table 2 below:

TABLE 2

Wherein the test standard of the tensile strength IS IS0527-2, the sample size IS 1A type (gauge length 115mm, parallel part 10mm multiplied by 4mm), and the tensile speed IS 50 mm/min; the bending strength test standard is ISO178, the sample size is 80mm multiplied by 10mm multiplied by 04mm (length multiplied by width multiplied by height), the bending speed is 2 mm/min; the notched Izod impact strength test standard is ISO179, and the specimen size is 80mm × 10mm × 4mm (notch retention width 8 mm); the test standard of the dielectric constant is GB/T1409-2006: the testing frequency is 1MHz, the size of a testing sample strip is 8mm multiplied by 3.2mm multiplied by 1.6mm (length multiplied by width multiplied by height), and the surface of the testing sample strip is uniformly coated with a silver electrode to test the dielectric constant; weather resistance test is carried out according to SAE J2527-2004, and the illumination amplitude is 0.55W/m²@340nm, the blackboard temperature in the illumination stage is 70 +/-2 ℃, the relative humidity is 50%, the blackboard temperature in the dark stage is 38 +/-2 ℃, the relative humidity is 95%, and the test time is 1000h, and the weather resistance of the sample is evaluated by testing the color difference change of the sample before and after the weather resistance test; heat distortion temperature was measured according to ISO75-2 standard and the sample size was80 mm. times.10 mm. times.4 mm (length. times.width. times.height).

From the test results in table 2, it can be seen that the polypropylene composite provided by the present invention has excellent properties of high strength, high weather resistance, low dielectric constant, etc.:

comparative example 2 is compared with example 1 except that the compatibilizer in example 1 was replaced with a polypropylene resin, and the results show that: compared with example 1, the mechanical properties such as tensile bending, impact and the like of comparative example 2 are obviously deteriorated, the dielectric constant is increased, meanwhile, the chromatic aberration is increased, the weather resistance is deteriorated, and the heat distortion temperature is reduced; according to the invention, polypropylene grafted maleic anhydride (PP-g-MAH) or polypropylene grafted glycidyl methacrylate (PP-g-GMA) is used as a compatilizer, so that the compatibility of a liquid crystal polymer and the surface of a polypropylene matrix resin is greatly increased, the bonding force between polymers is enhanced, the polymers are enriched at the interface between continuous phase PP and dispersed phase liquid crystal polymer, a good anchoring effect is achieved, the bonding degree of the continuous phase PP and the dispersed phase liquid crystal polymer is enhanced, and the compatibility is greatly improved;

comparative example 1 is compared with example 1 except that the liquid crystal polymer in example 1 is replaced with a polypropylene resin, and the results show that: compared with example 1, the tensile bending, impact and other mechanical properties of the comparative example 1 are poor, the dielectric constant is increased, the thermal deformation temperature is reduced, the color difference of the color plate is increased, and the weather resistance is poor; comparative example 3 is compared with example 1 except that the hollow glass beads in example 1 are replaced with polypropylene resin, and the results show that: compared with example 1, comparative example 3 maintains good tensile mechanical properties and high weather resistance, but the bending property is reduced, the dielectric constant is remarkably increased, and the heat distortion temperature is reduced; comparative example 4 is compared with example 1 except that the PTFE fine powder in example 1 is replaced with a polypropylene resin, and the results show that: comparative example 4 maintained good mechanical properties, but increased dielectric constant compared to example 1;

as can be seen from the comparison results of comparative examples 1, 3-4 and example 1, the liquid crystal polymer with self-reinforcing effect and hot-weather resistance is not added in comparative example 1, not only the mechanical property and thermal deformation temperature of the prepared material are reduced, but also the dielectric constant is increased and the weather resistance is poor, the hollow glass bead and PTFE micropowder are not added in comparative examples 3 and 4 respectively, the bending property is reduced and the dielectric constant is increased in comparative example 3, the dielectric constant is increased and the weather resistance is significantly reduced in comparative example 4, in conclusion, the invention utilizes the excellent mechanical property and heat resistance of the liquid crystal polymer to significantly improve the mechanical property and heat resistance of the material, and utilizes the synergistic combination of the liquid crystal polymer, the hollow glass bead and the PTFE micropowder, the mechanical property, heat resistance, dielectric constant, weather resistance and other properties of the material are comprehensively improved.

Comparative example 5 is compared with example 1, except that the antioxidant in example 1 is replaced with a weather-resistant auxiliary; comparative example 6 is compared with example 1 except that the weather-resistant auxiliary in example 1 is replaced with an antioxidant; comparative example 7 is compared with example 1 except that the weather-resistant auxiliary and the antioxidant in example 1 are both replaced with polypropylene resin; the results show that: compared with example 1, comparative examples 5 to 6 maintain good mechanical properties, the dielectric constant and the heat distortion temperature are basically unchanged, but the chromatic aberration is obviously increased, and the weather resistance is deteriorated; compared with example 1, comparative example 7 maintains good mechanical properties, the dielectric constant and the heat distortion temperature are basically unchanged, but the chromatic aberration is obviously increased, and the weather resistance is deteriorated; compared with a comparative example 7, the color difference of comparative examples 5 to 6 is obviously reduced, the weather resistance is improved, but the weather resistance cannot reach the excellent level of the example 1;

from the comparison results of comparative examples 5 to 6 with comparative example 7 and example 1, it can be seen that: the dosage of the weather-resistant agent adopted in the comparative example 5 is equal to the total dosage of the antioxidant and the weather-resistant auxiliary agent in the example 1, but the weather resistance is poorer than that of the example 1, but the weather resistance is improved compared with the comparative example 7 in which the antioxidant and the weather-resistant auxiliary agent are not added; the antioxidant used in the comparative example 6 is equal to the total amount of the antioxidant and the weather-resistant auxiliary agent used in the example 1, and the weather-resistant performance is still poorer than that of the example 1, but the weather-resistant performance is improved compared with the comparative example 7 in which the antioxidant and the weather-resistant auxiliary agent are not added; from this it follows: according to the invention, the antioxidant and the weather-resistant auxiliary agent are added, so that the weather resistance is effectively improved, the antioxidant and the weather-resistant auxiliary agent are compounded and used according to a certain proportion, and the heat resistance of the liquid crystal polymer is synergistically matched with the efficient antioxidant and light stabilizing system (light stabilizer), so that the prepared polypropylene composite material has excellent weather resistance.

Comparative example 8 is significantly reduced in mechanical properties and reduced in heat distortion temperature, while the dielectric constant is increased, as compared with example 1. According to the invention, the hollow glass beads are added from the side feeding port, so that the damage of the screw to the hollow glass beads can be reduced, and the prepared polypropylene composite material has lower dielectric constant and excellent mechanical property.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.