CN113667299B

CN113667299B - Antistatic polyamide composition and preparation method and application thereof

Info

Publication number: CN113667299B
Application number: CN202110862523.7A
Authority: CN
Inventors: 叶少勇; 杨硕; 陈家达; 黄险波; 徐显骏; 姜苏俊; 曹民; 龙杰明; 麦杰鸿; 陈平绪; 叶南飚
Original assignee: Kingfa Science and Technology Co Ltd; Zhuhai Vanteque Speciality Engineering Plastics Co Ltd
Current assignee: Kingfa Science and Technology Co Ltd; Zhuhai Vanteque Speciality Engineering Plastics Co Ltd
Priority date: 2021-07-29
Filing date: 2021-07-29
Publication date: 2023-04-11
Anticipated expiration: 2041-07-29
Also published as: CN113667299A; WO2023005726A1

Abstract

The invention discloses an antistatic polyamide composition, which comprises the following components in parts by weight: 60 parts of polyamide resin; 2-18 parts of isotropic pitch carbon fiber; 10-40 parts of mineral fiber; 0.05-5 parts of nano-structured carbon; the mineral fiber is selected from at least one of wollastonite fiber, calcium sulfate fiber, calcium silicate fiber, aluminum silicate fiber and sepiolite fiber. By compounding isotropic pitch carbon fibers, mineral fibers and nanostructured carbon, the defects on the surface of a workpiece can be effectively reduced, and the workpiece has good antistatic dust absorption and self-dust absorption resistance.

Description

Antistatic polyamide composition and preparation method and application thereof

Technical Field

The invention relates to the technical field of high polymer materials, in particular to an antistatic polyamide composition and a preparation method and application thereof.

Background

With the development of modern technology, imaging systems are rapidly popularized in daily life, and the key of the imaging systems is various lenses, such as mobile phone camera module lenses, notebook computer/AIO all-in-one lenses, monitoring lenses, vehicle-mounted lenses, scanner lenses, multimedia television built-in camera lenses, and the like. The existing lens is modularized and called as a camera module, and mainly comprises a lens, a voice coil motor, a photosensitive chip, a sensor, an infrared filter, a circuit board and other components.

As an important component of the camera module, the plastic lens holder needs to have the following characteristics: heat resistance, adhesiveness, dimensional stability, moldability, low dust generation property, and surface smoothness.

In the using process, the definition of the imaging effect of the camera is continuously reduced along with the prolonging of the using time, the main reason is that the lens is polluted by granular dust (the size is larger than 10 μm), the granular dust mainly comes from two aspects, one is external dust caused by the untight module packaging, the dust pollution is greatly related to the electrostatic dust collection effect of an insulating plastic material in the module, the other important source is granules (the main component is a filler in the plastic lens support) falling out when the plastic lens support is vibrated or rubbed in transmission, and therefore, as a lens support material, the camera should have the characteristics of antistatic dust collection as high as possible and low spontaneous dust generation so as to keep the lens clean for a long time.

Regarding the surface smoothness, on the one hand, the plastic material lens holder plays a role not only in supporting the lens but also in driving support during the lens extension and retraction, and the surface smoothness of the material has an important influence on the lubricating and wear-resistant characteristics during the driving movement, and therefore, the material is required to have high surface smoothness in order to obtain excellent lubricating and wear-resistant properties. On the other hand, parts with uneven surfaces are prone to falling off of fine particles during long-term use. Therefore, the surface smoothness is also strongly associated with low dust generation.

Among them, heat resistance, adhesiveness, dimensional stability, and moldability are satisfied by preference of the matrix resin or other means, and high surface smoothness can be surface-adjusted by the plastic filler. However, achieving both high surface smoothness and low dusting remains an industry challenge, involving the self-dusting and electrostatic dusting properties of the material.

Disclosure of Invention

The present invention has an object of overcoming the above-mentioned technical drawbacks and providing an antistatic polyamide composition having the advantages of surface smoothness, antistatic dust-collecting properties and antistatic dust-generating properties.

Another object of the present invention is to provide a process for the preparation and use of the above antistatic polyamide composition.

The invention is realized by the following technical scheme:

an antistatic polyamide composition comprises the following components in parts by weight:

60 parts of polyamide resin;

2-18 parts of isotropic pitch carbon fiber;

10-40 parts of mineral fiber;

0.05-5 parts of nano-structured carbon;

the mineral fiber is selected from at least one of wollastonite fiber, calcium sulfate fiber, calcium silicate fiber, aluminum silicate fiber and sepiolite fiber.

The polyamide resin is selected from at least one of semi-aromatic polyamide and aliphatic polyamide; the semi-aromatic polyamide is selected from at least one of PA6T/66, PA6I, PA6T/M5T, PA9T/66, PA10T/66, PA10T/10I, PA10T/1010, PA12T and PA 12I; the aliphatic polyamide is selected from at least one of PA6, PA66, PA610, PA612, PA1010, PA1012, PA1212, PA11 and PA 12.

The present invention does not particularly require the weight average molecular weight of the polyamide resin, and the object of the present invention can be achieved generally with a weight average molecular weight in the range of 5000 to 100000 g/mol.

The polyamide resin of the present invention may be selected from pure aliphatic polyamide, pure semi-aromatic polyamide, and a combination of aliphatic polyamide and semi-aromatic polyamide resins. When a combination of aliphatic polyamide and semi-aromatic polyamide resin or pure semi-aromatic polyamide is selected, preferably, based on the total weight of the polyamide resin, 75-100wt% of semi-aromatic polyamide and 0-25wt% of aliphatic polyamide are selected; more preferably, the semi-aromatic polyamide is 85 to 100wt% and the aliphatic polyamide is 0 to 15wt%, based on the total weight of the polyamide resin.

The average diameter of the isotropic pitch carbon fiber is 2-20 microns; preferably, the isotropic pitch-based carbon fiber has an average diameter of 12 to 14 μm.

The nano-structure carbon is selected from at least one of single-arm carbon nano-tubes, multi-arm carbon nano-tubes and forked array type carbon nano-structures; preferably, the nanostructured carbon is selected from multi-arm carbon nanotubes. The preferred nanostructured carbon forms a more extensive percolating structure network, while the antistatic polyamide composition articles have better surface smoothness and are less prone to self-abrasive dust generation over long periods of time.

In the prior art, the nano conductive carbon material includes graphene, graphdiyne, C60, nano carbon black, and the like, in addition to the nano structured carbon. However, in the system of the present invention, the nano conductive carbon material has a poor dispersibility as compared with the nano structured carbon, and thus the surface smoothness of the product is lowered, and self-abrasion dust is generated after a long time use.

Preferably, the nano-dimensional size of the nano-structured carbon is 0.5 to 50 nanometers.

The nano-dimensional size means: the dimension range of the nano object reaching the nano dimension in 3 dimensions (for an object, the shape and the size of the material can be defined through 3 spatial dimensions, for a nano-scale material, the nano concept does not need 3 dimensions to reach the nano scale, and the nano material can be called as the nano material only by reaching the nano scale by one dimension). Such as average diameter, average thickness, length, average length, particle size, average particle size, and the like.

The mineral fibers have an average diameter of 0.5 to 15 microns; preferably, the mineral fibers have an average diameter of 2 to 8 microns; preferably, the mineral fibers are selected from calcium sulfate fibers.

The antistatic polyamide composition of the invention has a volume resistivity value of 9.9X 10 or less ⁸ ohm·cm。

0-2 parts of antioxidant and ultraviolet resistant agent can be added according to actual requirements to improve the oxidation resistance, ultraviolet resistance and the like.

The antioxidant can be antioxidant 1010, etc., and the skilled person can select the type of antioxidant to add according to actual conditions.

According to the preparation method of the antistatic polyamide composition, the polyamide resin and the nano-structure carbon are uniformly mixed according to the proportion, then the mixture is added into a main feeding port of a double-screw extruder, various isotropic pitch carbon fibers are added into the double-screw extruder through a first side feeding machine, mineral fibers are added into the double-screw extruder through a second side feeding machine, and the mixture is subjected to melt extrusion and granulation to obtain the antistatic polyamide composition; wherein the rotation speed range of the screw is 200 to 500rpm, the length-diameter ratio is 40 to 48, and the temperature range is 270-320 ℃.

The antistatic polyamide composition is applied to preparing camera module components.

Compared with the prior art, the invention has the following beneficial effects

In order to realize good antistatic performance, the prior art mainly forms a percolation structure network required for antistatic by compounding a certain content of carbon fiber and nano-structure carbon (or other nano conductive carbon materials). However, if the carbon fiber content is too high, fiber floating defects may be caused due to its large microscopic size and extremely excellent heat transfer characteristics; if the content of the nano-structure carbon (or other nano conductive carbon materials) is too high, the surface of a workpiece is not smooth due to excessive gas inclusion and agglomeration inside the nano-structure carbon (or other nano conductive carbon materials), self-dust is easily generated, and a percolation structure network is also damaged.

In order to solve the technical defects, the viscosity of the system is improved by adding the mineral fiber, so that the shearing action of a screw on the melt of the composition is effectively transmitted during extrusion processing, and the dispersion/distribution condition of fillers (isotropic pitch carbon fiber, nano-structure carbon and mineral fiber) is obviously improved. Not only can the isotropic pitch carbon fiber and the nanostructured carbon form a good percolation structure network under low content, but also can the damage to the surface smoothness under high content of the isotropic pitch carbon fiber and the nanostructured carbon.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the invention.

The raw materials used in the invention are as follows:

PA6T/66: vicyl 4X, kingo science and technology, inc., weight average molecular weight 30000 g/mol;

PA10T: vicyl 7X, kingo science Inc., weight average molecular weight 10000g/mol;

PA10T/1010: vicyl 8X, king Kogyo Co., ltd., weight average molecular weight 7000 g/mol;

PA66: PA66 EPR24, shenma group, china, weight average molecular weight 20000g/mol;

PA612: zytel 153HSL NC010, duPont, USA, weight average molecular weight 100000g/mol;

PA12: grilamid L20 HL, EMS Switzerland, weight average molecular weight 70000g/mol;

calcium sulfate fiber a: DL-40H, average diameter 2 μm, new materials, guangwei, changzhou;

calcium sulfate fiber B: DL-30, average diameter 4 μm, new Material Inc., guangwei, changzhou;

calcium sulfate fiber C: DL-10, average diameter 8 μm, new Material Inc., guangwei, changzhou;

calcium sulfate fiber D: NP-M01, average diameter 0.7 μ M, jiangxi Pelargonium new Material science and technology Co., ltd;

calcium sulfate fiber E: calcium sulfate whisker with average diameter of 14 μm, new material of Jade element of Jinan, inc.

Wollastonite fiber: acicular wollastonite having an average diameter of 10 μm, jiangxi Hua Jie Tai mineral fibre science and technology Co., ltd;

calcium silicate fiber: MD1250-10012, average diameter 7 μm, shanghai hua zhong trade ltd;

aluminum silicate fiber: aluminum silicate powder with a diameter of 7 μm, shandong Ye refractory fiber Co., ltd;

sepiolite fibers: sepiolite fibers, 15 μm in diameter, shijiazhuanhui mineral products, inc.;

glass fiber: EC11-3.0, round chopped glass fiber with the average diameter of 10 μm, taiwan Corp;

magnesium sulfate fiber: NP-YW2, average diameter 4 μm, shanghai Pelargonium composite New Material science and technology Co., ltd;

polycrystalline mullite fiber: t-1600, average diameter 4 μm, kazuki Kanji Crystal fiber Limited;

alumina fiber: t-1700, average diameter 4 μm, kaaware Crystal fiber, zhejiang;

isotropic pitch-based carbon fiber a: DONAARBO S-242, average diameter 13 μm, osaka gas Chemicals, japan;

isotropic pitch-based carbon fiber B: DONAARBO S-344, average diameter 18 μm, osaka gas Chemicals, japan;

anisotropic pitch-based carbon fiber: XN80, average diameter 11 μm, japan graphite fibers Corp;

PAN-based carbon fiber: PX35CA0250-65, average diameter 7 μm, toray Japan;

single-arm carbon nanotubes: TUBALL single-walled carbon nanotubes, average diameter 2.0nm, oakhicle trade (Shenzhen) Limited;

multi-arm carbon nanotubes: NANOCYL NC7000, average diameter 9.5nm, produced by NANOCYL, belgium;

bifurcated arrayed carbon nanostructures: CNS, average nanometer dimension 5.0nm, cabot corporation;

graphite alkyne: average thickness 3nm, department of Chinese academy of sciences;

c60: fullerene C60, average particle size 0.71nm, haohnhong biological medicine science and technology Limited;

nano-scale carbon black: nano carbon black, average particle size 15nm, cabot corporation;

graphene: high-conductivity graphene powder with a flaky shape and a lamella thickness of 0.5nm, deyang alkene carbon technology, inc.;

antioxidant: antioxidant 1010, basf corporation.

Examples and comparative examples preparation of antistatic polyamide compositions: uniformly mixing polyamide resin and nano-structured carbon according to a ratio, adding the mixture into a main feeding port of a double-screw extruder, adding the isotropic pitch carbon fiber into the double-screw extruder through a first side feeding machine, adding the mineral fiber into the double-screw extruder through a second side feeding machine, and performing melt extrusion and granulation to obtain the antistatic polyamide composition; wherein, the rotation speed range of the screw is 300-400rpm, the length-diameter ratio is 48.

The test method comprises the following steps:

(1) Testing the dust generation property: the samples were injection molded into 40mm x 1.0mm plaques a, B, with the plaques tested in the following scenarios: (1) Immediately performing dust generation test within 2h after injection molding, wherein the sample is called an A sample plate; (2) The dust formation test (characterization of the antistatic dust absorption of the material) was carried out 168h after placing in a daily house (temperature 23 ℃, humidity 67%), this sample being referred to as B-panel. Placing the sample plate in 500mL of deionized water held by a beaker, placing the beaker with the sample in an ultrasonic cleaning machine, washing (ultrasonic frequency 40kHz, time A plate for 20 minutes and time B plate for 2 minutes), taking out the deionized water with the sample plate cleaned, placing the deionized water in a liquid pool, testing for 5 minutes at 23 ℃ by using a liquid particle counter, counting the amount Fa of dust with the diameter of more than 10 mu m by using a software program, and taking the amount Fa as a characteristic parameter of the dust generation property of the material, wherein the dust generation property rating is defined as follows: fa < 5 in the 1-grade (excellent), fa < 20 in the 2-grade (excellent), fa < 20 in the 3-grade (good), fa < 35 in the 4-grade (middle), fa < 50 in the 35-grade (poor), and Fa < 50 in the 5-grade (poor). The liquid particle counter is RION KS-42BF, and the ultrasonic cleaning machine is BK-240J. Wherein, grade 1-3 is qualified, and grade 1 and grade 2 belong to low self-dust-generation level.

(2) Volume resistivity: the volume resistivity of the material was calculated in ohmcm by measuring the current through a sample of the material (100 mm x 2.0 mm) held at 500V dc for 1 minute, as determined with reference to IEC 60093-1980.

(3) Surface roughness: the surface roughness of an injection molding sample plate of 40mm multiplied by 1.0mm is measured by referring to GB/T1031-2009, the surface roughness is evaluated by a contour method, the arithmetic mean deviation Ra value of the contour is selected as a characteristic parameter, the sampling reference length lr is preferably 2.5mm, and the evaluation length value of 5 multiplied by lr is selected during measurement so as to ensure the accuracy of the test, and the unit of the arithmetic mean deviation Ra value is mu m.

Table 1: EXAMPLES 1-11 antistatic Polyamide compositions content of Components (parts by weight) and test results

	Example 1	Example 2	Example 3	Example 4	Example 5
						PA6T/66	60
PA10T		60
						PA10T/1010			60
PA66				60
						PA612					60
PA12
						Isotropic pitch carbon fiber A	10	10	10	10	10
Calcium sulfate fiber A	20	20	20	20	20
						Single-arm carbon nanotube	2	2	2	2	2
Antioxidant agent	0.3	0.3	0.3	0.3	0.3
						Dust test (A templet)	Level 1	Level 1	Level 1	Stage 2	Stage 2
Dust test (B sample)	Level 1	Level 1	Level 1	Level 1	Level 1
						Volume resistivity, ohmcm	5.3×10 ⁶	8.8×10 ⁶	7.0×10 ⁶	9.2×10 ⁶	8.7×10 ⁶
Surface roughness, μm	0.10	0.11	0.09	0.18	0.19

From examples 1 to 11, it is understood that when a combination of an aliphatic polyamide and a semi-aromatic polyamide resin is used, the dust generation suppressing property (self-dust generation, electrostatic dust collection) is better and the surface smoothness is high (roughness is low) in the preferable semi-aromatic/aliphatic ratio. In particular, the surface roughness of purely aliphatic polyamide compositions is high, which leads to a somewhat poorer self-dusting resistance.

Continuing with Table 1:

	example 6	Example 7	Example 8	Example 9	Example 10	Example 11
							PA6T/66					45
PA10T	59	51	45	39
							PA10T/1010						45
PA66					15
							PA612	1	9	15	21
PA12						15
							Isotropic pitch carbon fiber A	10	10	10	10	10	10
Calcium sulfate fiber A	20	20	20	20	20	20
							Single-arm carbon nanotube	2	2	2	2	2	2
Antioxidant agent	0.3	0.3	0.3	0.3	0.3	0.3
							Dust test (A templet)	Level 1	Level 1	Level 1	Level 1	Level 1	Level 1
Dust test (B sample)	Level 1	Stage 2	Stage 2	Grade 3	Stage 2	Stage 2
							Volume resistivity, ohmcm	1.6×10 ⁷	4.2×10 ⁷	6.6×10 ⁷	5.1×10 ⁸	3.8×10 ⁷	5.0×10 ⁷
Surface roughness, μm	0.10	0.11	0.13	0.14	0.13	0.15

Table 2: EXAMPLES 12-20 antistatic Polyamide compositions content by weight parts and test results

	Example 12	Example 13	Example 14	Example 15	Example 16	Example 17	Example 18	Example 19	Example 20
										PA10T	45	45	45	45	45	45	45	45	45
PA612	15	15	15	15	15	15	15	15	15
										Isotropic pitch carbon fiber A	10	10	10	10	2	2	14	18	18
Calcium sulfate fiber A					10	10	25	30	40
										Calcium sulfate fiber B	20
Calcium sulfate fiber C		20
										Calcium sulfate fiber D			20
Calcium sulfate fiber E				20
										Single-arm carbon nanotube	2	2	2	2	0.05	0.8	3	5	5
Antioxidant agent	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3
										Dust test (A templet)	Level 1	Level 1	Level 1	Stage 2	Level 1	Level 1	Level 1	Stage 2	Stage 2
Dust test (B sample)	Stage 2	Stage 2	Stage 2	Stage 2	Grade 3	Grade 3	Stage 2	Stage 2	Level 1
										Volume resistivity, ohmcm	4.6×10 ⁷	7.1×10 ⁷	9.7×10 ⁷	0.6×10 ⁸	7.6×10 ⁸	4.7×10 ⁸	7.7×10 ⁷	3.0×10 ⁷	8.1×10 ⁶
Surface roughness, μm	0.13	0.14	0.09	0.17	0.12	0.13	0.15	0.18	0.20

From examples 8/12-15, it is preferred that the mineral fibers have an average diameter in the range of 2-8 microns.

From examples 8/16 to 20, it is understood that the volume resistivity is decreased with the increase in the content of the isotropic pitch-based carbon fiber and the one-armed carbon nanotube, but the surface roughness is increased, resulting in an increase in self-dust emission property.

Table 3: EXAMPLES 21-28 antistatic Polyamide compositions the content of each component (parts by weight) and the test results

	Example 21	Example 22	Example 23	Example 24	Example 25	Example 26	Example 27	Example 28
									PA10T	45	45	45	45	45	45	45	45
PA612	15	15	15	15	15	15	15	15
									Isotropic pitch carbon fiber A		10	10	10	10	10	10	10
Isotropic pitch carbon fiber B	10
									Calcium sulfate fiber A	20	20	20					20
Wollastonite fiber				20
									Calcium silicate fibres					20
Aluminium silicate fibre						20
									Sepiolite fiber							20
Single-arm carbon nanotube	2			2	2	2	2
									Multi-arm carbon nanotube		2						2
Bifurcated array carbon nanostructures			2
									Antioxidant agent	0.3	0.3	0.3	0.3	0.3	0.3	0.3
Dust test (A templet)	Stage 2	Level 1	Level 1	Stage 2	Level 1	Stage 2	Stage 2	Level 1
									Dust test (B sample)	Stage 2	Level 1	Stage 2	Stage 2	Stage 2	Stage 2	Grade 3	Level 1
Volume resistivity, ohmcm	1.7×10 ⁸	9.7×10 ⁶	4.6×10 ⁷	1.8×10 ⁸	0.9×10 ⁸	8.9×10 ⁷	2.2×10 ⁸	9.8×10 ⁶
									Surface roughness, μm	0.16	0.13	0.11	0.18	0.12	0.18	0.20	0.13

From examples 8/21, it is clear that the volume resistivity of the preferred antistatic polyamide composition of isotropic pitch-based carbon fibers is lower.

From examples 8/22/23, multi-arm carbon nanotubes and bifurcated array carbon nanostructures are preferred, and multi-arm carbon nanotubes are more preferred.

From examples 8/24 to 27, calcium sulfate fibers are preferred.

Table 4: comparative examples 1 to 7 antistatic Polyamide compositions content of Components (parts by weight) and test results

	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5	Comparative example 6	Comparative example 7
								PA10T	45	45	45	45	45	45	45
PA612	15	15	15	15	15	15	15
								Isotropic pitch-based carbon fiber A			10	10	10	10	10
Anisotropic pitch-based carbon fiber	10
								PAN-based carbon fiber		10
Calcium sulfate fiber A	20	20		20	20	20	20
								Glass fiber			20
Single arm carbon nanotube	2	2	2
								Graphtylene				2
C60					2
								Nano-scale carbon black						2
Graphene							2
								Antioxidant agent	0.3	0.3	0.3	0.3	0.3	0.3	0.3
Dust test (A templet)	Stage 2	Grade 4	Grade 5	Grade 3	Grade 4	Grade 3	4 stage
								Dust test (B sample)	4 stage	4 stage	Grade 5	Grade 5	Grade 4	Grade 5	Grade 5
Volume resistivity, ohmcm	1.5×10 ⁹	2.3×10 ⁹	5.0×10 ¹⁰	2.2×10 ¹⁰	9.4×10 ⁹	6.5×10 ¹⁰	8.1×10 ¹¹
								Surface roughness, μm	0.25	0.41	0.57	0.33	0.38	0.34	0.39

As can be seen from comparative examples 1/2, other carbon fibers were not as effective in the system of the present invention.

As can be seen from comparative example 3, the glass fiber cannot replace the mineral fiber of the present invention.

As can be seen from comparative examples 4 to 7, the technical effects of graphdiyne, C60, nano-scale carbon black and graphene are not good.

Table 5: comparative examples 8 to 11 antistatic Polyamide compositions content of Components (parts by weight) and test results

	Comparative example 8	Comparative example 9	Comparative example 10	Comparative example 11
					PA10T	45	45	45	45
PA612	15	15	15	15
					Isotropic pitch carbon fiber A	1	20	10	10
Calcium sulfate fiber A	20	20	20	20
					Single arm carbon nanotube	2	2	0.01	6
Antioxidant agent	0.3	0.3	0.3	0.3
					Dust test (A sample)	Stage 2	Stage 2	Level 1	Grade 3
Dust test (B sample)	Grade 5	Grade 4	Grade 5	4 stage
					Volume resistivity, ohmcm	8.1×10 ¹¹	4.8×10 ⁹	1.3×10 ¹⁰	6.1×10 ⁹
Surface roughness, μm	0.16	0.21	0.12	0.27

Table 6: comparative examples 12 to 14 antistatic Polyamide compositions content by weight and test results

	Comparative example 12	Comparative example 13	Comparative example 14
				PA10T	45	45	45
PA612	15	15	15
				Isotropic pitch carbon fiber A	10	10	10
Magnesium sulfate fiber	20
				Polycrystalline mullite fiber		20
Alumina fiber			20
				Single arm carbon nanotube	2	2	2
Antioxidant agent	0.3	0.3	0.3
				Dust test (A sample)	Grade 3	Grade 4	Grade 4
Dust test (B sample)	Grade 5	4 stage	Grade 5
				Volume resistivity, ohmcm	1.6×10 ¹¹	8.4×10 ⁹	5.3×10 ¹⁰
Surface roughness, μm	0.27	0.36	0.41

Claims

1. An antistatic polyamide composition is characterized by comprising the following components in parts by weight:

60 parts of polyamide resin;

2-18 parts of isotropic pitch carbon fiber;

10-40 parts of mineral fiber;

0.05-5 parts of nano-structured carbon;

the mineral fiber is selected from at least one of wollastonite fiber, calcium sulfate fiber, calcium silicate fiber, aluminum silicate fiber and sepiolite fiber, and the average diameter is 0.5-15 microns;

the average diameter of the isotropic pitch carbon fiber is 2-20 microns;

the nano-structure carbon is selected from at least one of single-arm carbon nanotubes, multi-arm carbon nanotubes and forked array type carbon nano-structures, and the nano-dimension of the nano-structure carbon is 0.5-50 nanometers.

2. The antistatic polyamide composition of claim 1 wherein the polyamide resin is at least one selected from the group consisting of semi-aromatic polyamides and aliphatic polyamides; the semi-aromatic polyamide is selected from at least one of PA6T/66, PA6I, PA6T/M5T, PA9T/66, PA10T/66, PA10T/10I, PA10T/1010, PA12T and PA 12I; the aliphatic polyamide is selected from at least one of PA6, PA66, PA610, PA612, PA1010, PA1012, PA1212, PA11 and PA 12.

3. The antistatic polyamide composition of claim 2 wherein the semi-aromatic polyamide is 75 to 100wt% and the aliphatic polyamide is 0 to 25wt% based on the total weight of the polyamide resin.

4. The antistatic polyamide composition according to claim 3, wherein the semi-aromatic polyamide is 85 to 100wt% and the aliphatic polyamide is 0 to 15wt%, based on the total weight of the polyamide resin.

5. Antistatic polyamide composition according to claim 1, characterized in that the isotropic pitch-based carbon fibers have an average diameter of 12-14 microns.

6. The antistatic polyamide composition of claim 1 wherein the nanostructured carbon is selected from multi-armed carbon nanotubes.

7. Antistatic polyamide composition according to claim 1, characterized in that the mineral fibers have an average diameter of 2-8 microns.

8. Antistatic polyamide composition according to claim 1, characterized in that the mineral fibers are selected from calcium sulfate fibers.

9. Antistatic polyamide composition according to any one of claims 1 to 8, characterized in that the antistatic polyamide composition has a volume resistivity value of 9.9 x 10 or less ⁸ ohm·cm。

10. The preparation method of the antistatic polyamide composition as claimed in any one of claims 1 to 9, characterized in that the polyamide resin and the nanostructured carbon are uniformly mixed according to the proportion, then the mixture is added into a main feeding port of a double-screw extruder, the isotropic pitch carbon fiber is added into the double-screw extruder through a first side feeding machine, the mineral fiber is added into the double-screw extruder through a second side feeding machine, and the mixture is subjected to melt extrusion and granulation to obtain the antistatic polyamide composition; wherein the rotation speed range of the screw is 200 to 500rpm, the length-diameter ratio is 1 to 48, and the temperature range is 270-320 ℃.

11. Use of the antistatic polyamide composition according to any one of claims 1 to 9 for the production of camera module parts.