A conductive polypropylene composition and preparation method thereof

Abstract

The present invention discloses a conductive polypropylene composition and a preparation method thereof, wherein the conductive polypropylene composition is prepared from the following components in parts by mass: 68.6 to 87.6 parts of polypropylene, 10 to 25 parts of conductive carbon black, 2 to 5 parts of coupling agents, 0.2 to 0.8 parts of tackifiers, and 0.2 to 0.6 parts of antioxidants; wherein the tackifier is white carbon black; and the conductive polypropylene composition is formed by processing the above components through a twin-screw extruder. In the present invention, a large amount of coupling agents are added to the conductive polypropylene system, and white carbon black is introduced as a tackifier, thereby significantly reducing the surface resistivity of the polypropylene composition, improving the conductive performance, and making it have an excellent mechanical property retention rate, so that the conductive polypropylene composition can be widely used in various scenarios in the fields of electronics and electrical engineering that require conductive materials, and has broad market prospects and application value.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to a conductive polypropylene composition and a preparation method thereof. Background Art

[0002] Polypropylene (PP) is a general-purpose plastic with light weight, high rigidity and high hardness, which is widely used in many fields. In specific applications, the performance of PP is usually improved by chemical or physical modification as needed. Among them, filling modification is one of the common methods, which is generally to add some functional fillers or functional additives to the polypropylene system to improve the heat resistance, conductivity, rigidity and toughness of PP.

[0003] For example, carbon black-filled polymer conductive composites are widely used in the fields of conductivity and conductive materials due to their good conductive effect. Adding conductive carbon black to the polypropylene system can prepare conductive and conductive polypropylene composites. In actual preparation, it is found that if you want to achieve a higher conductive effect, the amount of conductive carbon black added must reach a certain level. For example, if you want to achieve a surface resistivity of polypropylene material less than 10 8 , the amount of conductive carbon black added generally needs to reach more than 28%. However, the addition of a high proportion of filler will destroy the mechanical properties, affect the rigidity and toughness of the material, and the overall cost is high.

[0004] Therefore, it is urgent to find a low-cost solution to improve conductive polypropylene materials based on the current conductive polypropylene system. Summary of the invention

[0005] In view of this, the primary purpose of the present invention is to provide a conductive polypropylene composition. The present invention adds a large amount of coupling agent to the polypropylene system to prevent the agglomeration of conductive carbon black, and introduces white carbon black as a tackifier to improve the continuity and connectivity of the conductive carbon black in the material, thereby greatly improving the overall conductive properties of the polypropylene composition while ensuring the mechanical properties of the polypropylene composition.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] One aspect of the present invention provides a conductive polypropylene composition, which is prepared from the following components in parts by mass:

[0008] 68.6-87.6 parts of polypropylene, 10-25 parts of conductive carbon black, 2-5 parts of coupling agent, 0.2-0.8 parts of tackifier and 0.2-0.6 parts of antioxidant;

[0009] Wherein, the tackifier is white carbon black;

[0010] The conductive polypropylene composition is formed by processing the above components through a twin-screw extruder.

[0011] Another aspect of the present invention provides a method for preparing the conductive polypropylene composition as described above, comprising the following steps:

[0012] According to parts by mass, 68.6 to 87.6 parts of polypropylene, 10 to 25 parts of conductive carbon black, 2 to 5 parts of coupling agent, 0.2 to 0.8 parts of tackifier and 0.2 to 0.6 parts of antioxidant are fully mixed to obtain a uniform mixture;

[0013] The mixed material is added into a twin-screw extruder, and after melt extrusion, granulation and drying, a conductive polypropylene composition is obtained.

[0014] Beneficial effects of the present invention:

[0015] 1. The present invention adds cheap and readily available functional additives to the traditional conductive polypropylene material to improve the conductive properties of the polypropylene composition, which can effectively control the cost and is easy to expand and promote.

[0016] 2. The present invention adds a large amount of coupling agent to the conductive polypropylene formula, which, on the one hand, helps to prevent the agglomeration of conductive carbon black and helps to improve the dispersion of conductive carbon black in the polypropylene resin, thereby helping to improve the construction of conductive paths inside the polypropylene material and reduce the surface resistivity of the material; on the other hand, the addition of a large amount of coupling agent helps to increase the bonding strength between the matrix resin and the conductive carbon black, and reduces the size and number of gaps between the matrix resin and the conductive carbon black after crystallization, thereby reducing the surface resistivity of the material.

[0017] 3. The present invention innovatively introduces a thickener into the conductive polypropylene formula, and the thickener can play a key role in the screw shearing process. Specifically, the special chemical structure and physical properties of white carbon black can effectively improve the distribution of conductive carbon black in the polypropylene matrix. There is a synergistic mechanism between it, polypropylene and conductive carbon black, which can enhance the viscosity of the system, so that the conductive carbon black is more evenly dispersed inside the polypropylene material under the action of the screw shear force, reducing the occurrence of agglomeration. Through this uniform dispersion effect, the continuity and connectivity of the conductive carbon black in the material are significantly improved, thereby greatly improving the overall conductive performance of the material. Compared with traditional conductive polypropylene materials without the addition of thickeners, the conductive polypropylene material of the present invention has significant improvements in conductive performance indicators such as surface resistivity, and can be widely used in various scenarios in the fields of electronics, electrical engineering, etc. where conductive materials are needed, and has broad market prospects and application value. DETAILED DESCRIPTION

[0018] Embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0019] The first aspect of the present invention discloses a conductive polypropylene composition, which is prepared from the following components in parts by mass:

[0020] 68.6-87.6 parts of polypropylene, 10-25 parts of conductive carbon black, 2-5 parts of coupling agent, 0.2-0.8 parts of tackifier and 0.2-0.6 parts of antioxidant;

[0021] Wherein, the tackifier is white carbon black;

[0022] The conductive polypropylene composition is formed by processing the above components through a twin-screw extruder.

[0023] In the present invention, the polypropylene is not particularly limited and may be any conventional type in the art, specifically, may be at least one of copolymer polypropylene and homopolymer polypropylene.

[0024] In the present invention, the conductive carbon black is not particularly limited. Preferably, the conductive carbon black is a powder with a mass content greater than 98%. More preferably, the conductive carbon black is a high-structure carbon black. High-structure carbon black, also known as porous carbon black, is a material whose carbon black particles have a very high pore structure and surface area. There are usually a large number of micropores and mesopores between the particles of this carbon black, so that its specific surface area can reach hundreds to thousands of square meters per gram. Therefore, compared with other conductive carbon blacks, high-structure carbon black, due to its advantages of being highly structured, porous and highly active, can better improve the conductivity of the material.

[0025] In the present invention, the coupling agent is a type of additive that can improve the interface characteristics between polymer materials and fillers. Its molecular structure contains two groups with different properties: one part of the group can form a chemical bond with an inorganic material or filler, and the other part of the group has an organic affinity and can react chemically or form a physical bond with an organic molecule. This structure of the coupling agent enables the coupling agent to act as a "molecular bridge" between the inorganic filler and the organic polymer, thereby improving the performance of the composite material, including physical properties, electrical properties, thermal properties, optical properties, etc. In some specific embodiments of the present invention, the coupling agent is a silane coupling agent, and specific examples that can be mentioned include at least one of KH550 and KH570, but are not limited to this.

[0026] In the present invention, the antioxidant is a kind of auxiliary agent commonly used in polymer materials to improve their antioxidant properties, and the specific types include at least one of hindered amine antioxidants, hindered phenol antioxidants, and phosphite antioxidants, wherein the hindered amine antioxidant can be antioxidant 1010, antioxidant 1076, etc.; the hindered phenol antioxidant can be 2,6-di-tert-butyl-4-methylphenol (BHT), bis(3,5-di-tert-butyl-4-hydroxyphenyl) sulfide, tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol, etc.; the phosphite antioxidant is usually used as an auxiliary antioxidant, which can be trioctyl ester, tridecyl ester, tri(dodecanol) ester and tri(hexadecanol) ester, and can also be antioxidant 168, etc. However, it is not limited to the above examples.

[0027] The second aspect of the present invention discloses a method for preparing the conductive polypropylene composition according to the first aspect of the present invention, comprising the following steps:

[0028] According to parts by mass, 68.6 to 87.6 parts of polypropylene, 10 to 25 parts of conductive carbon black, 2 to 5 parts of coupling agent, 0.2 to 0.8 parts of tackifier and 0.2 to 0.6 parts of antioxidant are fully mixed to obtain a uniform mixture;

[0029] The mixed material is added into a twin-screw extruder, and after melt extrusion, granulation and drying, a conductive polypropylene composition is obtained.

[0030] Among them, the mixing method is not particularly limited. The conventional mechanical mixing method in the art, such as a high-speed mixer, can be used to evenly mix the raw material components. The specific parameters such as the rotation speed and mixing time can be adjusted or optimized by those skilled in the art according to actual needs, so they are not specifically limited here.

[0031] Furthermore, the rotation speed and processing temperature of the twin-screw extruder can be determined by those skilled in the art based on the specific composition of the raw materials through experience in the field or known experimental methods. In some specific embodiments of the present invention, the rotation speed of the twin-screw extruder is 300-500 rpm; and / or the processing temperature in the barrel is 190-240°C.

[0032] The present invention is described below by specific examples, it should be noted that the following specific examples are only for illustrative purposes, and do not limit the scope of the present invention in any way, unless otherwise defined, all technical and scientific terms used herein are identical with the meanings generally understood by the technicians belonging to the technical field of the present invention. The term used in the specification of the present invention herein is only for the purpose of describing specific embodiments, and is not intended to limit the present invention. In addition, if not otherwise specified, the method for not specifically recording conditions or steps is a conventional method, and the reagents and materials adopted can be obtained from commercial sources.

[0033] The raw material information in the following examples and comparative examples is as follows:

[0034] Polypropylene: PP YPJ1215C (Yangzi Petrochemical), PP T30S (Yanchang Petrochemical), PP BX3800 (SK Chemical, South Korea).

[0035] Conductive carbon black: N110 (Tianjin Youmeng Chemical Technology Co., Ltd.), VXC72 (Cabot).

[0036] White carbon black: LM150 (Cabot)

[0037] Coupling agent: KH550 (Nanjing Nengde New Materials Co., Ltd.), KH570 (Guangzhou Longkai Chemical Co., Ltd.)

[0038] Antioxidants: Hindered phenol antioxidant 1010 (Lianlong), phosphite antioxidant 168 (BASF), hindered amine antioxidant Chimassorb 944 (BASF).

[0039] Example 1

[0040] This embodiment provides a method for preparing a conductive polypropylene composition, and the specific steps are as follows:

[0041] According to the mass parts, 74.1 parts of polypropylene PP BX3800, 22 parts of conductive carbon black VXC72, 3 parts of coupling agent KH550, 0.5 parts of tackifier white carbon black LM150, 0.2 parts of antioxidant 1010, and 0.2 parts of antioxidant 168 were added to a high-speed mixer, mixed evenly, and then added to a twin-screw extruder from the main material port, melt-extruded, granulated and dried to obtain a conductive polypropylene composition;

[0042] Among them, the temperature of the twin-screw extruder from the feeding section to the die head is 210°C, 210°C, 210°C, 220°C, 220°C, 220°C, 210°C, 210°C, and the rotation speed is 400rpm.

[0043] Example 2

[0044] This embodiment provides a method for preparing a conductive polypropylene composition, and the specific steps are as follows:

[0045] According to the mass parts, 71.1 parts of polypropylene PP T30S, 24 parts of conductive carbon black N110, 4 parts of coupling agent KH550, 0.6 parts of tackifier white carbon black LM150, and 0.3 parts of antioxidant 168 were added to a high-speed mixer, mixed evenly, and then added to a twin-screw extruder from the main material port, melt-extruded, granulated and dried to obtain a conductive polypropylene composition;

[0046] Among them, the temperature of the twin-screw extruder from the feeding section to the die head is 200°C, 200°C, 200°C, 210°C, 210°C, 210°C, 220°C, 220°C, and 210°C respectively, and the rotation speed is 500rpm.

[0047] Example 3

[0048] This embodiment provides a method for preparing a conductive polypropylene composition, and the specific steps are as follows:

[0049] According to the mass parts, 75.3 parts of polypropylene PP YPJ1215C, 20 parts of conductive carbon black N110, 4 parts of coupling agent KH570, 0.4 parts of tackifier white carbon black LM150, 0.1 parts of antioxidant 168, and 0.2 parts of antioxidant Chimassorb944 were added to a high-speed mixer, mixed evenly, and then added to a twin-screw extruder from the main material port, melt-extruded, granulated and dried to obtain a conductive polypropylene composition;

[0050] Among them, the temperature of the twin-screw extruder from the feeding section to the die head is 220°C, 220°C, 220°C, 220°C, 230°C, 230°C, 230°C, 210°C, 210°C, and the rotation speed is 360rpm.

[0051] Example 4

[0052] This embodiment provides a method for preparing a conductive polypropylene composition, and the specific steps are as follows:

[0053] According to the mass parts, 87.6 parts of polypropylene PP T30S, 10 parts of conductive carbon black VXC72, 2 parts of coupling agent KH570, 0.2 parts of tackifier white carbon black LM150, and 0.2 parts of antioxidant Chimassorb944 were added to a high-speed mixer, mixed evenly, and then added to a twin-screw extruder from the main material port, melt-extruded, granulated and dried to obtain a conductive polypropylene composition;

[0054] Among them, the temperature of the twin-screw extruder from the feeding section to the die head is 190°C, 190°C, 190°C, 200°C, 200°C, 210°C, 210°C, 200°C, and the rotation speed is 300rpm.

[0055] Example 5

[0056] This embodiment provides a method for preparing a conductive polypropylene composition, and the specific steps are as follows:

[0057] According to the mass parts, 68.6 parts of polypropylene PP YPJ1215C, 25 parts of conductive carbon black N110, 5 parts of coupling agent KH550, 0.8 parts of tackifier white carbon black LM150, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, and 0.2 parts of antioxidant Chimassorb944 were added to a high mixer, mixed evenly, and then added to a twin-screw extruder from the main material port, melt-extruded, granulated and dried to obtain a conductive polypropylene composition;

[0058] Among them, the temperature of the twin-screw extruder from the feeding section to the die head is 220°C, 220°C, 220°C, 230°C, 230°C, 230°C, 240°C, 240°C, 230°C, and 230°C respectively, and the rotation speed is 500rpm.

[0059] Comparative Example 1

[0060] This comparative example provides another method for preparing a conductive polypropylene composition, and the specific preparation steps are as follows:

[0061] According to the mass parts, 77.6 parts of polypropylene PP BX3800, 22 parts of conductive carbon black VXC72, 0.2 parts of antioxidant 1010 and 0.2 parts of antioxidant 168 were added to a high-speed mixer, mixed evenly, and then added to a twin-screw extruder from the main feed port, melt-extruded, granulated and dried to obtain a conductive polypropylene composition;

[0062] Among them, the temperature of the twin-screw extruder from the feeding section to the die head is 210°C, 210°C, 210°C, 220°C, 220°C, 220°C, 210°C, 210°C, and the rotation speed is 400rpm.

[0063] Comparative Example 2

[0064] This comparative example provides another method for preparing a conductive polypropylene composition, and the specific preparation steps are as follows:

[0065] According to the mass parts, 77.1 parts of polypropylene PP BX3800, 22 parts of conductive carbon black VXC72, 0.5 parts of tackifier white carbon black LM150, 0.2 parts of antioxidant 1010, and 0.2 parts of antioxidant 168 were added to a high-speed mixer, mixed evenly, and then added to a twin-screw extruder from the main material port, melt-extruded, granulated and dried to obtain a conductive polypropylene composition;

[0066] Among them, the temperature of the twin-screw extruder from the feeding section to the die head is 210°C, 210°C, 210°C, 220°C, 220°C, 220°C, 210°C, 210°C, and the rotation speed is 400rpm.

[0067] Comparative Example 3

[0068] This comparative example provides another method for preparing a polypropylene composition, and the specific preparation steps are as follows:

[0069] According to the mass parts, 74.6 parts of polypropylene PP BX3800, 22 parts of conductive carbon black VXC72, 3 parts of coupling agent KH550, 0.2 parts of antioxidant 1010, and 0.2 parts of antioxidant 168 were added to a high-speed mixer, mixed evenly, and then added to a twin-screw extruder from the main material port, melt-extruded, granulated and dried to obtain a conductive polypropylene composition;

[0070] Among them, the temperature of the twin-screw extruder from the feeding section to the die head is 210°C, 210°C, 210°C, 220°C, 220°C, 220°C, 210°C, 210°C, and the rotation speed is 400rpm.

[0071] Performance Testing

[0072] The conductive polypropylene compositions in Examples 1-5 and Comparative Examples 1-3 were subjected to relevant performance tests, and the specific test methods and conditions are as follows:

[0073] (1) Tensile strength: refer to ISO 527, test conditions: 23°C, tensile speed 50 mm / min.

[0074] (2) Flexural strength and flexural modulus: refer to ISO 178, test conditions: 23°C, bending speed 2 mm / min.

[0075] (3) Izod notched impact strength: refer to ISO 180, test condition: 23°C.

[0076] (4) Surface resistivity: refer to ASTM D257.

[0077] The test results are shown in Table 1.

[0078] Table 1 Conductive polypropylene composition performance test results

[0079]

[0080] It can be seen from the test results in Table 1 that in the present invention, when a lower conductive carbon black addition amount (mass proportion not exceeding 25%) is used, a lower surface resistivity can be achieved, the conductive properties of the conductive polypropylene composition are significantly improved, and the mechanical property retention rate of the obtained conductive polypropylene composition is higher.

[0081] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0082] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A conductive polypropylene composition, characterized in that: It is prepared from the following components in parts by mass: Polypropylene 68.6-87.6 parts, conductive carbon black 10-25 parts, coupling agent 2-5 parts, tackifier 0.2-0.8 parts and antioxidant 0.2-0.6 parts; Wherein, the tackifier is white carbon black; The conductive polypropylene composition is formed by processing the above components through a twin-screw extruder.

2. The conductive polypropylene composition according to claim 1, characterized in that The polypropylene is at least one of copolymer polypropylene and homopolymer polypropylene.

3. The conductive polypropylene composition according to claim 1, characterized in that The conductive carbon black is a powder with a mass concentration greater than 98%.

4. The conductive polypropylene composition according to claim 1 or 3, characterized in that: The conductive carbon black is high-structure carbon black.

5. The conductive polypropylene composition according to claim 1, characterized in that The coupling agent is a silane coupling agent.

6. The conductive polypropylene composition according to claim 5, characterized in that The silane coupling agent is at least one of KH550 and KH570.

7. The conductive polypropylene composition according to claim 1, characterized in that The antioxidant is at least one of a hindered amine antioxidant, a hindered phenol antioxidant, and a phosphite antioxidant.

8. A method for preparing a conductive polypropylene composition according to any one of claims 1 to 7, characterized in that: The following steps are involved: According to parts by mass, 68.6 to 87.6 parts of polypropylene, 10 to 25 parts of conductive carbon black, 2 to 5 parts of coupling agent, 0.2 to 0.8 parts of tackifier and 0.2 to 0.6 parts of antioxidant are fully mixed to obtain a uniform mixture; The mixed material is added into a twin-screw extruder, and after melt extrusion, granulation and drying, a conductive polypropylene composition is obtained.

9. The preparation method according to claim 8, characterized in that: The rotation speed of the twin-screw extruder is 300-500 rpm; and / or the processing temperature in the barrel is 190-240° C.

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