High-gloss antistatic polypropylene composite material as well as preparation method and application thereof

Abstract

The invention provides a high-gloss antistatic polypropylene composite material as well as a preparation method and application thereof, and relates to the technical field of high-performance polypropylene materials. The polypropylene composite material provided by the invention comprises the following components in parts by weight: 70-89 parts of polypropylene; 8-20 parts of a composite conductive filler; 2-8 parts of a compatilizer; 0.4 to 1 part of an antioxidant; 0.3 to 1 part of a lubricant; wherein the composite conductive filler comprises a graphene coated mica sheet and an ionic liquid functionalized carbon nanotube in a mass ratio of (1.5-2): 1. Through the composite conductive filler and the structural design, the antistatic property, the mechanical property and the surface glossiness of the polypropylene material can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-performance polypropylene materials, and particularly relates to a high-gloss antistatic polypropylene composite material and a preparation method and application thereof. BACKGROUND

[0002] Polypropylene (PP) has become a general-purpose plastic with a yield only next to polyethylene due to its light weight, excellent chemical stability, good mechanical properties, easy processing and molding, and recyclability, and has been widely used in the fields of automobile parts, electronic and electrical housings, furniture, industrial packaging, and medical devices, etc. However, the inherent high volume resistivity of polypropylene materials makes them extremely easy to accumulate static electricity, which not only affects the surface cleanliness of polypropylene during use, but also interferes with the normal function of electronic equipment, and even causes discharge risk in flammable and explosive environments. In addition, the surface friction resistance of commonly used polypropylene materials is poor, and the surface gloss is easily attenuated during long-term use.

[0003] There are two major technical routes in the prior art to improve the antistatic performance of polypropylene materials. One is to uniformly disperse conductive fillers in the polypropylene matrix to establish a conductive network, for example, adding about 15% of conductive carbon black or about 2% of carbon nanotubes to polypropylene. However, a large amount of conductive carbon black added will greatly affect the mechanical properties of polypropylene materials, and although a small amount of carbon nanotubes can achieve excellent conductive performance, carbon nanotubes are prone to agglomeration and sedimentation in polypropylene. The second is to cover a conductive layer as a coating on the surface of polypropylene to achieve antistatic performance. However, this method is simple and direct, but is prone to wear and tear during long-term use, and has poor durability. Therefore, there is an urgent need to provide a solution to improve the above problems. SUMMARY

[0004] The present application aims to provide a high-gloss antistatic polypropylene composite material and a preparation method and application thereof, which can improve the antistatic performance, mechanical properties and surface gloss of polypropylene materials through composite conductive fillers and structural design.

[0005] In a first aspect, the present application provides a high-gloss antistatic polypropylene composite material, which comprises, by weight: 70-89 parts of polypropylene; 8-20 parts of composite conductive fillers; 2-8 parts of a compatibilizer; 0.4-1 part of an antioxidant; and 0.3-1 part of a lubricant; wherein the composite conductive fillers comprise graphene-coated mica flakes and ionic liquid functionalized carbon nanotubes at a mass ratio of (1.5-2):1.

[0006] Optionally, the method for preparing the graphene-coated mica sheet comprises: depositing graphene on the surface of the mica sheet by physical vapor deposition; wherein the number of deposited layers of the graphene is 1-3 layers; the coverage of the graphene on the surface of the mica sheet is greater than or equal to 80%; and the aspect ratio of the mica sheet is 50-100.

[0007] Optionally, the method for preparing the ionic liquid functionalized carbon nanotube comprises: mixing and reacting carbon nanotubes with ionic liquid in a solvent environment at 80-100℃ for 20-28 hours to obtain ionic liquid functionalized carbon nanotubes; wherein the ionic liquid comprises 1-butyl-3-methylimidazolium hexafluorophosphate; and the grafting rate of the ionic liquid on the surface of the carbon nanotube is 10%-30%.

[0008] Optionally, the antioxidant comprises at least one of pentaerythritol bisphosphite di(2,4-di-tert-butylphenyl) ester, phosphite tris(2,4-di-tert-butylphenyl) ester, and tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] pentaerythritol ester.

[0009] Optionally, the lubricant comprises at least one of erucic acid amide, pentaerythritol stearate, and chlorinated polyethylene wax.

[0010] Optionally, the compatibilizer is PP grafted maleic anhydride, and the melt flow rate of the PP grafted maleic anhydride at 230℃ under a load of 2.16kg is 10-50g / 10min, and the grafting rate of the PP grafted maleic anhydride is 0.8%-1.2%.

[0011] Optionally, the melt flow rate of the polypropylene at 230℃ under a load of 2.16kg is 8-70g / 10min.

[0012] In a second aspect, the application further provides a method for preparing the polypropylene composite material, comprising: uniformly mixing polypropylene, a compatibilizer, an antioxidant, and a lubricant to obtain a mixture; and mixing and melt-extruding the mixture and the composite conductive filler, and then drawing, cooling, air-drying, and granulating to obtain the polypropylene composite material.

[0013] Optionally, when mixing, the mixture is added to a main feeder, the composite conductive filler is added to a side feeder, and mixing is performed in a twin-screw extruder; and the temperature of the twin-screw extruder is set in the order of 160-180℃, 190-200℃, 200-210℃, 210-220℃, 200-210℃, 200-210℃, 190-200℃, 180-190℃, and 190-200℃.

[0014] In a third aspect, the application further provides an application of any of the polypropylene composite materials described above, and the application includes the field of preventing static electricity in electronic packaging, medical devices, mining equipment, etc.

[0015] The high-gloss antistatic polypropylene composite material provided by the application has at least one of the following beneficial technical effects compared with the prior art: 1. By using graphene-coated mica flakes and ion liquid functionalized carbon nanotubes as composite conductive fillers, a stable conductive network can be constructed in the polypropylene composite material, and the two-dimensional sheet shielding structure formed by the graphene-coated mica flakes can effectively reduce the surface resistance and in turn reduce the volume resistance of the polypropylene composite material. 2. By using ion liquid to functionalize the surface of the carbon nanotubes and then compounding the ion liquid with the graphene-coated mica flakes, the ion liquid can effectively improve the dispersibility of the carbon nanotubes and the graphene-coated mica flakes in the polypropylene composite material and reduce the interfacial resistance, and the graphene layer coated on the surface of the mica flakes can inhibit the migration of the ion liquid on the surface of the carbon nanotubes, thereby being conducive to improving the structural stability of the polypropylene composite material. DETAILED DESCRIPTION

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are some but not all of the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the application. Unless otherwise defined, the technical terms or scientific terms used herein should have the usual meanings understood by those of ordinary skill in the art.

[0017] Embodiments 1-5 Embodiments 1-5 respectively provide a high-gloss antistatic polypropylene composite material, and the ingredients and amounts used are shown in Table 1 below.

[0018] Table 1 Ingredients and amounts of polypropylene composite materials in embodiments 1-5

[0019] In embodiments 1-5, the polypropylene used is PP H-MM20-S purchased from Maoming Petrochemical Company, with a melt index of 20 g / 10 min; the compatibilizer used is PP grafted maleic anhydride of Arkema ORREVAC CA100; the antioxidant used is 1010 purchased from Jiangsu Jieyi New Material Co., Ltd.; and the lubricant used is erucamide with the brand ER-CH purchased from the United Kingdom.

[0020] The preparation method of the graphene-coated mica sheet used in Examples 1-5 includes: placing the mica sheet (purchased from Shenzhen Haiyang Powder Technology Co., Ltd., model HY-CM1, diameter-thickness ratio 80) in the furnace of a vapor deposition device, introducing argon for gas replacement, then heating to 300°C at a rate of 10°C / min in a vacuum environment, sputtering graphene on the surface of the mica sheet, controlling the number of sputtered layers of graphene to be 3, and then cooling to obtain the graphene-coated mica sheet.

[0021] The preparation method of the ionic liquid functionalized carbon nanotube used in Examples 1-5 includes: stirring and dissolving 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM) in deionized water to obtain a mixed solution, adding single-walled carbon nanotubes (purchased from Shandong Dazhan Nanometer Material Co., Ltd., model GT-1001) into the mixed solution (mass ratio of carbon nanotubes to BMIM is 1:10) in a 90°C water bath environment, ultrasonic mixing uniformly, stirring for 24h, filtering and drying to obtain the ionic liquid functionalized carbon nanotube.

[0022] The preparation method of the polypropylene composite material in Examples 1-5 includes the following steps: pre-mixing polypropylene, compatibilizer, antioxidant, and lubricant in a mixer at high speed for 5min to obtain a mixture; adding the mixture into a main feeder, and adding the composite conductive filler into a side feeder, and then mixing in a twin-screw extruder, and then melt extruding, drawing, water cooling, air drying, and granulating to obtain the polypropylene composite material.

[0023] Specifically, during the mixing process in the twin-screw extruder in Examples 1-5, the temperature of the twin-screw extruder is set as follows: 165°C-180°C, 190°C-200°C, 200°C-210°C, 210°C-220°C, 200°C-210°C, 200°C-210°C, 190°C-200°C, 180°C-190°C, 190°C-200°C; the rotation speed of the twin-screw extruder in the high shear zone is 400rpm, and the rotation speed in the low shear zone is 100rpm.

[0024] Comparative Example 1 Comparative Example 1 is pure PP material.

[0025] Comparative Example 2 The high-gloss antistatic polypropylene composite material provided by Comparative Example 2 is different from Example 1 in that the ingredients and amounts used are as follows: 84 parts of polypropylene (from the same source as Example 1), 10 parts of conductive carbon black (purchased from Cabot XC-72), 5 parts of compatibilizer (from the same source as Example 1), 0.4 parts of antioxidant (from the same source as Example 1), and 0.6 parts of lubricant (from the same source as Example 1).

[0026] Performance testing The polypropylene composite materials in Examples 1-5 and Comparative Examples 1-2 were tested for the following items, and the test results are shown in Table 2 below: Notched impact strength test: ISO 180 standard, unit kJ / m 2 ; Tensile strength: ISO 527 standard, unit Mpa; Flexural strength and flexural modulus: ISO 178 standard, unit Mpa; Melt index: ISO 1133-1 standard, unit g / 10min; Surface resistivity: ASTM D257 standard, unit Ω; Resistance change rate after aging for 168h: test condition is 85 degrees / 85% RH, unit %.

[0027] Table 2 Performance test results of polypropylene composite materials

[0028] As can be seen from Table 2, the initial values of the surface resistivity of the polypropylene composite materials in Examples 1-5 are all less than 10 8 , reaching an excellent antistatic level, and after aging for 168h, the resistivity increases slightly, but the increase is less than 30%, still within the order of 10 8 , showing good long-term stability. In addition, the impact strength and melt index of the polypropylene composite materials in Examples 1-5 are both decreased to a certain extent compared with Comparative Example 1, and as can be seen from Examples 1 and 3, the increase of the compatibilizer is beneficial to the improvement of the comprehensive performance and antistatic performance of the composite materials.

[0029] Although the embodiments of the present application have been described in detail above, it is obvious to those skilled in the art that various modifications and changes can be made to these embodiments. However, it should be understood that such modifications and changes all fall within the scope and spirit of the present application as described in the claims. Moreover, the present application described herein can have other embodiments and can be implemented or realized in various ways.

Claims

1. A high-gloss, antistatic polypropylene composite material, characterized in that, The product comprises, by weight: 70-89 parts polypropylene; 8-20 parts composite conductive filler; 2-8 parts compatibilizer; 0.4-1 part antioxidant; and 0.3-1 part lubricant; wherein the composite conductive filler comprises graphene-coated mica sheets and ionic liquid functionalized carbon nanotubes in a mass ratio of (1.5-2):

1.

2. The polypropylene composite material according to claim 1, characterized in that, The method for preparing the graphene-coated mica sheet includes: depositing graphene on the surface of the mica sheet using physical vapor deposition; wherein the number of graphene deposition layers is 1 to 3; the coverage of the graphene on the surface of the mica sheet is greater than or equal to 80%; and the aspect ratio of the mica sheet is 50 to 100.

3. The polypropylene composite material according to claim 1, characterized in that, The method for preparing ionic liquid-functionalized carbon nanotubes includes: mixing carbon nanotubes with an ionic liquid in a solvent environment at 80℃-100℃ for 20h-28h, and then separating the ionic liquid-functionalized carbon nanotubes; wherein the ionic liquid includes 1-butyl-3-methylimidazolium hexafluorophosphate; and the grafting rate of the ionic liquid on the surface of the carbon nanotubes is 10%-30%.

4. The polypropylene composite material according to claim 1, characterized in that, The antioxidant includes at least one of pentaerythritol diphosphite di(2,4-di-tert-butylphenyl) ester, tri(2,4-di-tert-butylphenyl) phosphite, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

5. The polypropylene composite material according to claim 1, characterized in that, The lubricant includes at least one of erucamide, pentaerythritol stearate, and chlorinated polyethylene wax.

6. The polypropylene composite material according to claim 1, characterized in that, The compatibilizer is PP grafted maleic anhydride, and the melt flow rate of the PP grafted maleic anhydride under the conditions of 230℃ and 2.16kg is 10g / 10min-50g / 10min, and the grafting rate of the PP grafted maleic anhydride is 0.8%-1.2%.

7. The polypropylene composite material according to claim 1, characterized in that, The polypropylene has a melt flow rate of 8 g / 10 min to 70 g / 10 min at 230 °C and 2.16 kg.

8. A method for preparing a polypropylene composite material as described in any one of claims 1 to 7, characterized in that, include: A mixture is prepared by uniformly mixing polypropylene, compatibilizer, antioxidant and lubricant; the mixture is then kneaded with composite conductive filler and melt-extruded, followed by wire drawing, cooling, air drying and granulation to obtain polypropylene composite material.

9. The preparation method according to claim 9, characterized in that, During the mixing process, the mixture is added to the main feeder and the composite conductive filler is added to the side feeder, and then the mixture is mixed in a twin-screw extruder. The temperatures of the twin-screw extruder are set sequentially as follows: 160℃-180℃, 190℃-200℃, 200℃-210℃, 210℃-220℃, 200℃-210℃, 200℃-210℃, 190℃-200℃, 180℃-190℃, and 190℃-200℃.

10. The use of a polypropylene composite material as described in any one of claims 1 to 7.

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