A method for preparing functional masterbatch of array carbon nanotube polycarbonate and composite material

Abstract

This invention relates to the technical field of composite material preparation, specifically to a method for preparing a functional masterbatch of polycarbonate with arrayed carbon nanotubes and the resulting composite material. The method for preparing the functional masterbatch of polycarbonate with arrayed carbon nanotubes includes the following steps: heating a high-speed mixer to 90-100°C, adding arrayed carbon nanotubes, a silane coupling agent, and a lubricant to the high-speed mixer and mixing uniformly to obtain a premix; adding the premix, polycarbonate, a dispersant, and an antioxidant to a Banbury mixer and mixing to obtain a uniform semi-molten material; forcibly feeding the semi-molten material into a twin-screw extruder using a twin-cone feeder, and after mixing, shearing, and extrusion in the twin-screw extruder, discharging it into a single-screw extruder; after homogenization again in the single-screw extruder, extruding and granulating. This preparation method uniformly disperses arrayed carbon nanotubes in polycarbonate resin. Composite materials produced using this functional masterbatch exhibit excellent mechanical properties, electrical conductivity or antistatic properties, and surface finish, making them widely applicable.

Description

Technical Field

[0001] The invention relates to the technical field of composite material preparation, and in particular to a method for preparing an array carbon nanotube polycarbonate functional masterbatch and a composite material. Background Art

[0002] Carbon nanotubes are a one-dimensional nanomaterial with a special structure. The hexagonal structure of carbon atoms is perfectly connected, light in weight, and has many excellent mechanical, electrical and chemical properties such as high strength and good conductivity. The arrangement of array-type carbon nanotubes is more orderly, with better orientation, low degree of entanglement and easy dispersion, which can better exert its excellent characteristics. Polycarbonate resin, also known as PC plastic, is a high molecular polymer containing carbonate groups in the molecular chain. It is one of the five major engineering plastics and has good mechanical properties, high transparency and excellent electrical insulation properties. Array carbon nanotube-polycarbonate composite materials can combine the performance advantages of the two materials, so that the composite materials can be applied to more fields and products.

[0003] Due to the large specific surface area of ​​carbon nanotubes, they are easy to agglomerate when blended with polymers, making it difficult for the composite material to show its superiority. Chinese patent CN108276755A discloses a composite material for electromagnetic shielding and its preparation method, the preparation method comprising the following steps: polycarbonate resin, reinforcing filler, antistatic agent, toughening agent, lubricant, antioxidant, and compatibilizer are placed in a high-speed mixer and mixed for 3-5 minutes according to the ratio; then the mixture is added to the extruder, the carbon nanotubes are added to the twin-screw extruder from the side feed port for extrusion, and the barrel temperature of the twin-screw extruder is set within the range of 200-250°C; the extruded strips are cooled to room temperature through a circulating water tank, dried by a hair dryer, and then granulated in a granulator to obtain the composite material for electromagnetic shielding. The patent claims that the above preparation method effectively disperses carbon nanotubes in polycarbonate resin, greatly improving the antistatic effect of the composite material, but no relevant data support is given. Moreover, the above method fails to achieve effective dispersion of carbon nanotubes in the actual production process. Summary of the invention

[0004] In view of the technical problems that carbon nanotubes in existing carbon nanotube-polycarbonate composites are easy to agglomerate and the performance of the composite materials is poor, the present invention provides a method for preparing an array carbon nanotube-polycarbonate functional masterbatch and a composite material, in which the array carbon nanotubes are evenly dispersed in a polycarbonate resin. The composite material produced using the functional masterbatch has better mechanical properties and conductive or antistatic properties, and can be better applied in special fields.

[0005] In a first aspect, the present invention provides a method for preparing an array carbon nanotube polycarbonate functional masterbatch, comprising the following steps:

[0006] (1) raising the temperature of a high-speed mixer to 90-100° C., adding 1-15 parts by weight of array carbon nanotubes, 1-2 parts by weight of a silane coupling agent, and 1-2 parts by weight of a lubricant into the high-speed mixer and mixing them uniformly to obtain a premix;

[0007] (2) adding the premix, 78 to 96 parts by weight of polycarbonate, 1 to 2 parts by weight of a dispersant, and 0.1 to 1 part by weight of an antioxidant into an internal mixer and mixing them until they are in a uniform semi-molten state to obtain a semi-molten material;

[0008] (3) feeding the semi-molten material into a twin-screw extruder by force using a double-cone feeder, and then discharging the material into a single-screw extruder after being mixed, sheared and extruded by the twin-screw extruder;

[0009] (5) After being homogenized again by a single screw extruder, the product is extruded and granulated to obtain an array carbon nanotube polycarbonate functional masterbatch.

[0010] Furthermore, the lubricant is one or more of polyethylene wax, erucic acid amide, and stearic acid. Under the condition of high-speed mixing at 90-100° C., the lubricant is vaporized and uniformly coated on the surface of the array carbon nanotubes, which is beneficial to improve its dispersibility in polycarbonate.

[0011] Furthermore, the arrayed carbon nanotubes are one or both of an arrayed single-walled carbon nanotube and an arrayed multi-walled carbon nanotube.

[0012] Furthermore, the dispersant is one or both of pentaerythritol stearate and ethylene bisstearamide.

[0013] Furthermore, the antioxidant is one or both of a phosphite antioxidant and a hindered phenol antioxidant.

[0014] Furthermore, the mixing speed of the high-speed mixer is 500-1000 rpm.

[0015] Furthermore, the cavity temperature of the double cone feeder is 270-280°C.

[0016] Furthermore, the temperature of each temperature zone of the twin-screw extruder is 250-260° C., and the screw speed is 400-450 rpm.

[0017] Furthermore, the temperature of each temperature zone of the single-screw extruder is 250-260° C., the head temperature is 260-270° C., and the screw speed is 60-80 rpm.

[0018] In a second aspect, the present invention further provides a method for preparing an array carbon nanotube polycarbonate composite material, comprising:

[0019] The array carbon nanotube polycarbonate functional masterbatch and polycarbonate resin are added into a mixer and mixed evenly, and then extruded and granulated into an array carbon nanotube polycarbonate composite material using a twin-screw extruder.

[0020] The beneficial effects of the present invention are:

[0021] In the preparation method of the functional masterbatch of array carbon nanotube polycarbonate and composite material provided by the present invention, after the array carbon nanotubes are pre-treated, they are first pre-mixed with polycarbonate in an internal mixer at high temperature to a semi-molten state, so that the components of the material are evenly distributed; then they are extruded by a twin-screw-single-screw two-stage extruder, wherein the twin-screw extruder further mixes and shears the material, and the single-screw extruder further homogenizes the material, and has a certain balancing effect on the extrusion pressure, thereby improving the processing performance; finally, the array carbon nanotubes are evenly dispersed in the polycarbonate resin to obtain the functional masterbatch of array carbon nanotube polycarbonate. The polycarbonate composite material prepared using the above functional masterbatch has better mechanical properties, conductive or antistatic properties and surface conditions, and has a wide range of applications, thereby improving the use value of the array carbon nanotubes in the polycarbonate composite material. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] The sources of raw materials used in the following examples and comparative examples are as follows:

[0024] Arrayed multi-walled carbon nanotubes GT-210, from Shandong Dazhan Nanomaterials Co., Ltd.;

[0025] Arrayed multi-walled carbon nanotubes GT-220, from Shandong Dazhan Nanomaterials Co., Ltd.;

[0026] Polycarbonate resin was purchased from Wanhua Chemical Group, brand PC-A1220;

[0027] The dispersant was purchased from Salon, USA, brand PETS-GLYCOLUBE-P;

[0028] Silane coupling agent was purchased from Yunsheng Chemical Co., Ltd., brand KH560;

[0029] Polyethylene wax was purchased from Mitsui & Co., Ltd., Japan, brand HI-WAX 1105A;

[0030] Antioxidant 168 was purchased from Beijing Jiyi Chemical Co., Ltd.;

[0031] Antioxidant 1076 was purchased from Beijing Jiyi Chemical Co., Ltd.

[0032] Example 1

[0033] A carbon nanotube polycarbonate array functional masterbatch, the preparation method of which comprises the following steps:

[0034] (1) raising the temperature of a high-speed mixer to 90° C., adding 15 parts by weight of array multi-walled carbon nanotubes GT-210, 1 part by weight of a silane coupling agent, and 2 parts by weight of polyethylene wax into the high-speed mixer and mixing them uniformly at a mixing speed of 800 rpm to obtain a premix;

[0035] (2) adding the above premix, 79.4 parts by weight of polycarbonate, 2 parts by weight of dispersant, 0.2 parts by weight of antioxidant 168 and 0.4 parts by weight of antioxidant 1076 into an internal mixer and mixing them until they are in a uniform semi-molten state to obtain a semi-molten material;

[0036] (3) The cavity temperature of the double-cone feeder is controlled at 270-280° C. The semi-molten material is forced to be fed into the twin-screw extruder by the double-cone feeder. The temperature of each temperature zone of the twin-screw extruder is 250-260° C. The screw speed is 400 rpm. After being mixed, sheared and extruded by the twin-screw extruder, the material is discharged into the single-screw extruder;

[0037] (4) The temperature of each temperature zone of the single screw extruder is 250-260° C., the head temperature is 260° C., and the screw speed is 60 rpm. After the material is homogenized again by the single screw extruder, it is extruded and granulated to obtain the array carbon nanotube polycarbonate functional masterbatch.

[0038] Comparative Example 1

[0039] Weigh the same weight portions of array multi-walled carbon nanotubes GT-210, polycarbonate, dispersant, silane coupling agent, polyethylene wax, antioxidant 168 and antioxidant 1076 as in Example 1, add them into a mixer and mix evenly; use a twin-screw extruder with the temperature in each temperature zone at 250-260°C and the screw speed at 400rpm to extrude and granulate to form a polycarbonate functional masterbatch.

[0040] Comparative Example 2

[0041] Weigh 15 parts by weight of array multi-walled carbon nanotubes GT-210 and 85 parts by weight of polycarbonate, add them into a mixer and mix them evenly; use a twin-screw extruder with the temperature of each temperature zone at 250-260°C and the screw speed at 400rpm to extrude and granulate to prepare a polycarbonate functional masterbatch.

[0042] The standard for surface appearance evaluation is: the product with almost no pitting on the surface is excellent, the product with slight pitting on the surface is good, the product with obvious pitting on the surface is fair, and the product with many pitting on the surface is poor.

[0043] From the surface appearance, the surface condition of the array carbon nanotube polycarbonate functional masterbatch prepared in Example 1 is excellent, the surface condition of the polycarbonate functional masterbatch prepared in Comparative Example 1 is good, and the surface condition of the polycarbonate functional masterbatch prepared in Comparative Example 2 is fair.

[0044] Example 2

[0045] (1) The high-speed mixer is heated to 100° C., 15 parts by weight of array multi-walled carbon nanotubes GT-220, 1 part by weight of a silane coupling agent, and 2 parts by weight of polyethylene wax are added to the high-speed mixer and mixed evenly at a mixing speed of 800 rpm to obtain a premix;

[0046] (2) adding the above premix, 79.4 parts by weight of polycarbonate, 2 parts by weight of dispersant, 0.2 parts by weight of antioxidant 168 and 0.4 parts by weight of antioxidant 1076 into an internal mixer and mixing them until they are in a uniform semi-molten state to obtain a semi-molten material;

[0047] (3) The cavity temperature of the double-cone feeder is controlled at 270-280° C. The semi-molten material is forced to be fed into the twin-screw extruder by the double-cone feeder. The temperature of each temperature zone of the twin-screw extruder is 250-260° C. The screw speed is 450 rpm. The material is mixed, sheared, and extruded by the twin-screw extruder and then discharged into the single-screw extruder;

[0048] (4) The temperature of each temperature zone of the single screw extruder is 250-260° C., the head temperature is 270° C., and the screw speed is 80 rpm. After the material is homogenized again by the single screw extruder, it is extruded and granulated to obtain the array carbon nanotube polycarbonate functional masterbatch.

[0049] Comparative Example 3

[0050] Weigh the same weight portions of array multi-walled carbon nanotubes GT-220, polycarbonate, dispersant, silane coupling agent, polyethylene wax, antioxidant 168 and antioxidant 1076 as in Example 2, add them into a mixer and mix evenly; use a twin-screw extruder with the temperature in each temperature zone at 250-260°C and the screw speed at 450rpm to extrude and granulate to form a polycarbonate functional masterbatch.

[0051] Comparative Example 4

[0052] Weigh 15 parts by weight of array multi-walled carbon nanotubes GT-220 and 85 parts by weight of polycarbonate, add them into a mixer and mix them evenly; use a twin-screw extruder, use a twin-screw extruder, set the temperature in each temperature zone at 250-260°C, and the screw speed at 450rpm to extrude and granulate to make a polycarbonate functional masterbatch.

[0053] The surface appearance evaluation is the same as above. From the perspective of surface appearance, the surface condition of the array carbon nanotube polycarbonate functional masterbatch prepared in Example 2 is good, the surface condition of the polycarbonate functional masterbatch prepared in Comparative Example 1 is fair, and the surface condition of the polycarbonate functional masterbatch prepared in Comparative Example 2 is poor.

[0054] Dilution Validation

[0055] The masterbatch prepared in Examples 1-2 and Comparative Examples 1-4 and the polycarbonate resin were mixed in a mass ratio of 2:3, added to a mixer and mixed evenly, and extruded and granulated into a polycarbonate composite material using a twin-screw extruder with a temperature in each temperature zone of 250-260° C. and a screw speed of 450 rpm.

[0056] The performance of polycarbonate composite materials made from different masterbatches was tested, and the various test and evaluation methods used are as follows:

[0057] 1. Surface resistivity test: The test sample is injection molded into a 100mm×100mm×3mm test sample, and the surface resistance of the sample is tested using a DC resistance tester.

[0058] 2. Mechanical properties test:

[0059] (1) Impact resistance test: The test sample was injection molded into a 80 mm × 10 mm × 4 mm test specimen, and after being made by a notched specimen making machine, it was tested using a simply supported beam notched impact tester.

[0060] (2) Tensile property test: The test sample was injection molded into a dumbbell-shaped specimen and tested using a universal testing machine.

[0061] (3) Bending performance test: The test sample was injection molded into a 80 mm × 10 mm × 4 mm test specimen and tested using a universal testing machine.

[0062] 3. Surface appearance evaluation: The product with almost no pitting on the surface is excellent, the product with slight pitting on the surface is good, the product with obvious pitting on the surface is fair, and the product with many pitting on the surface is poor.

[0063] The test results are shown in Table 1:

[0064] Table 1 Performance test results of polycarbonate composites made from different masterbatches

[0065]

[0066] As can be seen from Table 1, after dilution verification, the electrical conductivity and surface condition of the polycarbonate composite material prepared by the preparation method provided by the present invention are significantly better than those of the polycarbonate composite material prepared by the ordinary twin-screw extrusion preparation process, and the mechanical properties of the composite material are also comprehensively improved.

[0067] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily conceive of changes or substitutions within the technical scope disclosed by the present invention, and such changes or substitutions shall be within the scope of protection of the present invention.

Claims

1. A method for preparing an array carbon nanotube polycarbonate functional masterbatch, characterized in that: The following steps are involved: (1) The temperature of a high-speed mixer is raised to 90-100° C., 1-15 parts by weight of array carbon nanotubes, 1-2 parts by weight of a silane coupling agent, and 1-2 parts by weight of a lubricant are added to the high-speed mixer and mixed evenly. The mixing speed of the high-speed mixer is 500-1000 rpm to obtain a premix; the lubricant is one or more of polyethylene wax, erucamide, and stearic acid; (2) adding the premix, 78-96 parts by weight of polycarbonate, 1-2 parts by weight of dispersant, and 0.1-1 parts by weight of antioxidant into an internal mixer and mixing until the mixture is in a uniform semi-molten state to obtain a semi-molten material; the dispersant is one or both of pentaerythritol stearate and ethylene bisstearamide; (3) The semi-molten material is forced to be fed into the twin-screw extruder by a double-cone feeder, and after being mixed, sheared and extruded by the twin-screw extruder, it is discharged into the single-screw extruder; the temperature of each temperature zone of the twin-screw extruder is 250~260℃, and the screw speed is 400~450rpm; (4) After being homogenized again by a single screw extruder, the array carbon nanotube polycarbonate functional masterbatch is obtained by extrusion granulation; the temperature of each temperature zone of the single screw extruder is 250~260℃, the head temperature is 260~270℃, and the screw speed is 60~80rpm.

2. The preparation method according to claim 1, characterized in that The arrayed carbon nanotubes are one or both of arrayed single-walled carbon nanotubes and arrayed multi-walled carbon nanotubes.

3. The preparation method according to claim 1, characterized in that: The antioxidant is one or both of a phosphite antioxidant and a hindered phenol antioxidant.

4. The preparation method according to claim 1, characterized in that: The cavity temperature of the double cone feeder is 270~280℃.

5. A method for preparing an array carbon nanotube polycarbonate composite material, characterized in that: include: The array carbon nanotube polycarbonate functional masterbatch prepared by the preparation method according to any one of claims 1 to 4 and the polycarbonate resin are added into a mixer and mixed evenly, and then extruded and granulated into an array carbon nanotube polycarbonate composite material using a twin-screw extruder.

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