WO2023005726A1 - Antistatic polyamide composition, preparation method therefor, and use thereof - Google Patents

Abstract

Disclosed in the present invention is an antistatic polyamide composition that comprises, in parts by weight, the following components: 60 parts of a polyamide resin, 2-18 parts of isotropic pitch-based carbon fibers, 10-40 parts of mineral fibers, and 0.05-5 parts of nano-structure carbon, wherein the mineral fibers are selected from at least one of wollastonite fibers, calcium sulfate fibers, calcium silicate fibers, aluminum silicate fibers, and sepiolite fibers. By compounding the isotropic pitch-based carbon fibers, the mineral fibers, and the nano-structure carbon, defects on the surface of a workpiece can be effectively reduced, and a good antistatic dust-absorbing property and spontaneous dust resistance can also be achieved.

Description

A kind of antistatic polyamide composition and its preparation method and application technical field

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

Background technique

With the development of modern technology, the imaging system is rapidly popularized in daily life. The key to the imaging system is the lens. There are various types of lenses, such as mobile phone camera module lenses, laptop/AIO all-in-one machine lenses, and monitoring lenses. , Car lens, scanner lens, multimedia TV built-in camera lens, etc. The current lens has been modularized, called a camera module, which is mainly composed of a lens, a voice coil motor, a photosensitive chip, a sensor, an infrared filter, and a circuit board.

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

In the process of use, the imaging effect of the camera will continue to decrease with the prolongation of use time. The main reason is that the lens is polluted by granular dust (size greater than 10 μm), which mainly comes from two On the one hand, one is the external dust caused by the poor packaging of the module, and this kind of dust pollution is closely related to the electrostatic dust absorption effect of the insulating plastic material in the module. Another important source is that the plastic lens holder is vibrated or driven. The particles that fall out due to friction (the main component is the filler in it), therefore, as a lens holder material, it should have the highest possible anti-static dust absorption and low self-dusting characteristics to keep the lens clean for a long time.

Regarding the smoothness of the surface, on the one hand, the plastic material lens bracket not only plays a role of supporting the lens, but also plays a role of transmission support when the lens expands and contracts. The surface smoothness of the material has an important influence on the lubrication and wear resistance characteristics during the transmission movement , Therefore, the material is required to have high surface smoothness in order to obtain excellent lubrication and wear resistance. On the other hand, workpieces with uneven surfaces are prone to drop tiny particles during long-term use. Therefore, surface smoothness is also closely related to low dust generation.

Among them, heat resistance, adhesiveness, dimensional stability, and molding performance can be satisfied by the optimization of matrix resin or other means, and high surface smoothness can be adjusted by plastic filling substances. However, achieving high surface smoothness and low dust generation at the same time is still a difficult problem in the industry, which involves the self-dust generation and electrostatic dust collection properties of the material.

Contents of the invention

The object of the present invention is to overcome the above-mentioned technical defects, and provide an antistatic polyamide composition, which has the advantages of smooth surface, good antistatic dust absorption and dust generation resistance.

Another object of the present invention is to provide the preparation method and application of the above antistatic polyamide composition.

The present invention is achieved through the following technical solutions:

An antistatic polyamide composition, by weight, comprises the following components:

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 PA6T/66, PA6I, PA6T/6I, PA6T/M5T, PA9T, PA9T/ 66. At least one of PA10T, PA10T/66, PA10T/10I, PA10T/1010, PA12T, PA12I; the aliphatic polyamide is selected from PA6, PA66, PA610, PA612, PA1010, PA1012, PA1212, PA11, At least one of PA12.

The present invention has no special requirement on the weight-average molecular weight of the polyamide resin. Generally speaking, the purpose of the present invention can be achieved if the weight-average molecular weight is within the range of 5000-100000 g/mol.

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

The average diameter of the isotropic pitch-based carbon fibers is 2-20 microns; preferably, the average diameter of the isotropic pitch-based carbon fibers is 12-14 microns.

The nanostructure carbon is selected from at least one of single-arm carbon nanotubes, multi-arm carbon nanotubes, and bifurcated array carbon nanostructures; preferably, the nanostructure carbon is selected from multi-arm carbon nanostructures. Tube. The percolation structure network formed by the preferred nanostructured carbon is better, and at the same time, the surface smoothness of the antistatic polyamide composition is better, and self-grinding dust is not easy to be generated after long-term use.

In the prior art, in addition to the above-mentioned nanostructured carbon, nano-conductive carbon materials also include graphene, graphyne, C60, nano-carbon black, and the like. However, in the system of the present invention, the dispersibility of the above-mentioned nano-conductive carbon material is not as good as that of nano-structured carbon, thereby reducing the surface smoothness of the workpiece, and self-wearing dust will be generated after long-term use.

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

The meaning of the nano-dimensional size is: the size range of the nano-dimensional in the three dimensions of the nano-object (for an object, the shape and size of the material can be defined through the three spatial dimensions, and for nano-scale materials, the nano-scale The concept does not require all three dimensions to reach the nanometer level, only one of the dimensions needs to reach the nanometer level to be called a nanomaterial). Such as average diameter, diameter, average thickness, thickness, length, average length, particle size, average particle size, etc.

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

The volume resistivity value of the antistatic polyamide composition of the present invention is less than or equal to 9.9×10 ⁸ ohm·cm.

0-2 parts of antioxidants and UV-resistant agents can be added according to actual needs to improve oxidation resistance, UV resistance, etc.

The antioxidant can be antioxidant 1010, etc., and technicians can choose the type of antioxidant to add according to the actual situation.

According to the preparation method of the antistatic polyamide composition of the present invention, the polyamide resin and nano-structured carbon are uniformly mixed according to the ratio, and then added to the main feeding port of the twin-screw extruder, and the isotropic pitch-based carbon fiber is fed through the first side. The feeder is added to the twin-screw extruder, and the mineral fiber is added to the twin-screw extruder through the second side feeder, melted, extruded, and granulated to obtain an antistatic polyamide composition; wherein, the screw speed range is 200 ～500rpm, aspect ratio is 40:1～48:1, temperature range is 270-320℃.

The application of the antistatic polyamide composition of the present invention is used for preparing camera module components.

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

In order to achieve good antistatic performance, the existing technology mainly forms the percolation structure network required for antistatic by compounding a certain amount of carbon fiber and nano-structured carbon (or other nano-conductive carbon materials). However, if the carbon fiber content is too high, it will cause floating fiber defects due to its large microscopic size and excellent heat transfer characteristics; if the nanostructured carbon (or other nano-conductive carbon materials) (or other nano-conductive carbon materials) too much internal air entrainment and agglomeration will cause the surface of the part to be uneven, which will easily cause self-dusting, and will also lead to the destruction of the percolation structure network.

In order to solve the above-mentioned technical defects, the present invention increases the viscosity of the system by adding mineral fibers, so that the screw rod can effectively transmit the shearing effect on the melt of the composition during extrusion processing, so that the filler (isotropic pitch-based carbon fiber, nano Structural carbon, mineral fibers) dispersion/distribution is significantly better. It can not only make the isotropic pitch-based carbon fiber and nano-structure carbon form a good percolation structure network at a low content, but also inhibit the damage to surface smoothness at a high content of the isotropic pitch-based carbon fiber and nano-structure carbon.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

The raw material sources used in the present invention are as follows:

PA6T/66: Vicnyl 4X, Kingfa Science & Technology Co., Ltd., weight average molecular weight 30000g/mol;

PA10T: Vicnyl 7X, Kingfa Science & Technology Co., Ltd., weight average molecular weight 10000g/mol;

PA10T/1010: Vicnyl 8X, Kingfa Science & Technology Co., Ltd., weight average molecular weight 7000g/mol;

PA66: PA66 EPR24, China Shenma Group, weight average molecular weight 20000g/mol;

PA612: Zytel 153HSL NC010, DuPont, USA, weight average molecular weight 100000g/mol;

PA12: Grilamid L 20HL, Swiss EMS company, weight average molecular weight 70000g/mol;

Calcium sulfate fiber A: DL-40H, average diameter 2μm, Changzhou Guangwei New Material Co., Ltd.;

Calcium sulfate fiber B: DL-30, with an average diameter of 4 μm, Changzhou Guangwei New Material Co., Ltd.;

Calcium sulfate fiber C: DL-10, with an average diameter of 8 μm, Changzhou Guangwei New Material Co., Ltd.;

Calcium sulfate fiber D: NP-M01, average diameter 0.7μm, Jiangxi Fengzhu New Material Technology Co., Ltd.;

Calcium sulfate fiber E: calcium sulfate whiskers, average diameter 14μm, Jinan Qingyuyuan New Material Co., Ltd.;

Wollastonite fiber: needle-shaped wollastonite, with an average diameter of 10 μm, Jiangxi Huajietai Mineral Fiber Technology Co., Ltd.;

Calcium silicate fiber: MD1250-10012, average diameter 7μm, Shanghai Huazhongrong Trading Co., Ltd.;

Aluminum silicate fiber: aluminum silicate powder, diameter 7μm, Shandong Minye Refractory Fiber Co., Ltd.;

Sepiolite fiber: sepiolite fiber, diameter 15μm, Shijiazhuang Huijin Mining Products Co., Ltd.;

[Corrected 25.08.2022 under Rule 91]
Glass fiber: EC11-3.0, round chopped glass fiber, with an average diameter of 10 μm, Bicheng Company, Taiwan Province, China;

Magnesium sulfate fiber: NP-YW2, average diameter 4μm, Shanghai Fengzhu Composite New Material Technology Co., Ltd.;

Polycrystalline mullite fiber: T-1600, average diameter 4μm, Zhejiang Jiahua Crystal Fiber Co., Ltd.;

Alumina fiber: T-1700, average diameter 4μm, Zhejiang Jiahua Crystal Fiber Co., Ltd.;

Isotropic pitch-based carbon fiber A: DONACARBO S-242, average diameter 13 μm, Osaka Gas Chemical Co., Ltd., Japan;

Isotropic pitch-based carbon fiber B: DONACARBO S-344, average diameter 18 μm, Osaka Gas Chemical Co., Ltd., Japan;

Anisotropic pitch-based carbon fiber: XN80, average diameter 11μm, Japan Graphite Fiber Company;

PAN-based carbon fiber: PX35CA0250-65, with an average diameter of 7 μm, Toray Corporation of Japan;

Single-armed carbon nanotubes: TUBALL single-armed carbon nanotubes, with an average diameter of 2.0nm, Okosi Air Trading (Shenzhen) Co., Ltd.;

Multi-armed carbon nanotubes: NANOCYL NC7000, average diameter 9.5nm, Belgian NANOCYL company;

Forked array carbon nanostructures: CNS, average nano-dimensional size 5.0nm, Cabot Corporation;

Graphdiyne: average thickness 3nm, Institute of Chemistry, Chinese Academy of Sciences;

C60: Fullerene C60, average particle size 0.71nm, Shanghai Haohong Biomedical Technology Co., Ltd.;

Nano-scale carbon black: nano-carbon black, average particle size 15nm, Cabot Corporation;

Graphene: highly conductive graphene powder, flake shape, sheet thickness of 0.5nm, Deyang Carbon Technology Co., Ltd.;

Antioxidant: Antioxidant 1010, BASF.

Examples and comparative examples The preparation method of the antistatic polyamide composition: mix the polyamide resin and nanostructure carbon evenly according to the proportion, then add the main feeding port of the twin-screw extruder, pass the isotropic pitch-based carbon fiber through the first The feeder on one side is fed into the twin-screw extruder, and the mineral fiber is fed into the twin-screw extruder through the second side feeder, melted, extruded, and granulated to obtain an antistatic polyamide composition; wherein, the rotational speed of the screw The range is 300-400rpm, the aspect ratio is 48:1, and the temperature range is 270-320°C.

Test Methods:

(1) Dust generation test: The sample is injection molded into samples A and B of 40mm×40mm×1.0mm. The sample test scene is as follows: (1) The dust generation test is carried out immediately within 2 hours after the injection molding is completed. This sample is called A Sample; (2) After being placed in a daily house (temperature 23°C, humidity 67%) for 168 hours, the dust generation test (to characterize the antistatic and dust-absorbing properties of the material), this sample is called B sample. Place the template in 500mL of deionized water contained in a beaker, put the beaker containing the sample into an ultrasonic cleaner, and after washing (ultrasonic frequency 40kHz, time A board 20 minutes, B board 2 minutes), clean the sample Take out the deionized water and place it in a liquid pool, test it with a liquid particle counter at 23°C for 5 minutes, use a software program to count the number Fa of dust with a diameter greater than 10 μm, and use it as a characteristic parameter of the dust generation of the material. The dust generation rating is defined as follows : Grade 1 (excellent) is Fa<5, Grade 2 (excellent) is 5≤Fa<20, Grade 3 (good) is 20≤Fa<35, Grade 4 (medium) is 35≤Fa<50, Grade 5 (difference) is 50≤Fa. Among them, the instrument model of the liquid particle counter is RION KS-42BF, and the instrument model of the ultrasonic cleaner is BK-240J. Among them, grades 1-3 are qualified, and grades 1 and 2 belong to the low self-dusting level.

(2) Volume resistivity: measured with reference to IEC 60093-1980, the material sample (100mm×100mm×2.0mm) was kept under 500V DC for 1 minute, and the current passing through the sample material was measured, and calculated to obtain the material Volume resistivity, in ohm cm.

(3) Surface roughness: measure with reference to GB/T 1031-2009, use the contour method to test the surface roughness of the injection molded sample of 40mm×40mm×1.0mm, use the center line system (contour method) to evaluate the surface roughness, and select the contour The arithmetic mean deviation Ra value is used as a characterization parameter, the sampling reference length lr is preferably 2.5mm, and the evaluation length value of 5×lr is selected during measurement to ensure the accuracy of the test, and the unit of the arithmetic mean deviation Ra value is μm.

Table 1: Contents (parts by weight) and test results of each component of the antistatic polyamide composition of Examples 1-11

the	Example 1	Example 2	Example 3	Example 4	Example 5
PA6T/66	60	the	the	the	the
PA10T	the	60	the	the	the
PA10T/1010	the	the	60	the	the
PA66	the	the	the	60	the
PA612	the	the	the	the	60
PA12	the	the	the	the	the

Isotropic pitch-based carbon fiber A	10	10	10	10	10
Calcium Sulfate Fiber A	20	20	20	20	20
single-armed carbon nanotubes	2	2	2	2	2
antioxidant	0.3	0.3	0.3	0.3	0.3
Dust generation test (A sample)	Level 1	Level 1	Level 1	level 2	level 2
Dust generation test (B sample)	Level 1	Level 1	Level 1	Level 1	Level 1
Volume resistivity, ohm cm	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

It can be seen from Examples 1-11 that when a combination of aliphatic polyamide and semi-aromatic polyamide resin is used, the preferred semi-aromatic and aliphatic ratios have better dust generation suppression (self-dusting, electrostatic dust collection), And the surface smoothness is high (low roughness). In particular, pure aliphatic polyamide compositions have a higher surface roughness, which results in somewhat poorer self-dusting resistance.

Continuation of Table 1:

the	Example 6	Example 7	Example 8	Example 9	Example 10	Example 11
PA6T/66	the	the	the	the	45	the
PA10T	59	51	45	39	the	the
PA10T/1010	the	the	the	the	the	45
PA66	the	the	the	the	15	the
PA612	1	9	15	twenty one	the	the
PA12	the	the	the	the	the	15
Isotropic pitch-based carbon fiber A	10	10	10	10	10	10
Calcium Sulfate Fiber A	20	20	20	20	20	20
single-armed carbon nanotubes	2	2	2	2	2	2
antioxidant	0.3	0.3	0.3	0.3	0.3	0.3
Dust generation test (A sample)	Level 1	Level 1	Level 1	Level 1	Level 1	Level 1
Dust generation test (B sample)	Level 1	level 2	level 2	Level 3	level 2	level 2
Volume resistivity, ohm cm	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: Contents (parts by weight) and test results of each component of the antistatic polyamide composition of Examples 12-20

From Examples 8/12-15, it can be known that the average diameter of the mineral fibers is preferably in the range of 2-8 microns.

It can be seen from Examples 8/16-20 that with the increase of the content of isotropic pitch-based carbon fibers and single-armed carbon nanotubes, the volume resistivity decreases, but the surface roughness increases, resulting in an increase in self-dust generation.

Table 3: Contents (parts by weight) and test results of each component of the antistatic polyamide composition of Examples 21-28

It can be known from Example 8/21 that the preferred antistatic polyamide composition of isotropic pitch-based carbon fibers has a lower volume resistivity.

From Examples 8/22/23, it can be known that multi-armed carbon nanotubes and bifurcated array carbon nanostructures are preferred, and multi-armed carbon nanotubes are more preferred.

As can be seen from Examples 8/24-27, calcium sulfate fibers are preferred.

Table 4: Contents (parts by weight) and test results of each component of the antistatic polyamide composition of Comparative Example 1-7

It can be seen from Comparative Example 1/2 that in the system of the present invention, the technical effects of other carbon fibers are not good.

It can be seen from Comparative Example 3 that glass fiber cannot replace the mineral fiber of the present invention.

As can be seen from Comparative Examples 4-7, the technical effects of graphyne, C60, nano-scale carbon black, and graphene are not good.

Table 5: Contents (parts by weight) and test results of each component of the antistatic polyamide composition of Comparative Examples 8-11

the	Comparative example 8	Comparative example 9	Comparative example 10	Comparative example 11
PA10T	45	45	45	45
PA612	15	15	15	15
Isotropic pitch-based carbon fiber A	1	20	10	10
Calcium Sulfate Fiber A	20	20	20	20
single-armed carbon nanotubes	2	2	0.01	6
antioxidant	0.3	0.3	0.3	0.3
Dust generation test (A sample)	level 2	level 2	Level 1	Level 3
Dust generation test (B sample)	Level 5	level 4	Level 5	level 4
Volume resistivity, ohm cm	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: Contents (parts by weight) and test results of each component of the antistatic polyamide composition of Comparative Examples 12-14

the	Comparative example 12	Comparative example 13	Comparative example 14
PA10T	45	45	45
PA612	15	15	15
Isotropic pitch-based carbon fiber A	10	10	10
Magnesium Sulfate Fiber	20	the	the
polycrystalline mullite fiber	the	20	the
Alumina fiber	the	the	20
single-armed carbon nanotubes	2	2	2
antioxidant	0.3	0.3	0.3
Dust generation test (A sample)	Level 3	level 4	level 4
Dust generation test (B sample)	Level 5	level 4	Level 5
Volume resistivity, ohm cm	1.6×10 11	8.4×10 9	5.3×10 10

Surface roughness, μm

0.27

0.36

0.41

Claims (10)

1. An antistatic polyamide composition is characterized in that, by weight, it comprises the following components:

   

   The mineral fiber is selected from at least one of wollastonite fiber, calcium sulfate fiber, calcium silicate fiber, aluminum silicate fiber and sepiolite fiber.
2. Antistatic polyamide composition according to claim 1, is characterized in that, described polyamide resin is selected from at least one in semi-aromatic polyamide, aliphatic polyamide; Described semi-aromatic polyamide is selected from At least one of PA6T/66, PA6I, PA6T/6I, PA6T/M5T, PA9T, PA9T/66, PA10T, PA10T/66, PA10T/10I, PA10T/1010, PA12T, PA12I; the aliphatic polyamide At least one selected from PA6, PA66, PA610, PA612, PA1010, PA1012, PA1212, PA11, and PA12.
3. The antistatic polyamide composition according to claim 2, is characterized in that, preferably, based on the total weight of the polyamide resin, semi-aromatic polyamide 75-100wt%, aliphatic polyamide 0-25wt%; more preferably According to the total weight of the polyamide resin, the semi-aromatic polyamide is 85-100 wt%, and the aliphatic polyamide is 0-15 wt%.
4. The antistatic polyamide composition according to claim 1, wherein the average diameter of the isotropic pitch-based carbon fibers is 2-20 microns; preferably, the average diameter of the isotropic pitch-based carbon fibers 12-14 microns in diameter.
5. antistatic polyamide composition according to claim 1, is characterized in that, described nanostructure carbon is selected from single-arm carbon nanotube, multi-arm carbon nanotube, bifurcated array type carbon nanostructure at least One; Preferably, the nanostructured carbon is selected from multi-armed carbon nanotubes.
6. The antistatic polyamide composition according to claim 1 or 5, characterized in that the nano-dimensional size of the nanostructured carbon is 0.5-50 nanometers.
7. Antistatic polyamide composition according to claim 1, is characterized in that, the average diameter of described mineral fiber is 0.5-15 micron; Preferably, the average diameter of described mineral fiber is 2-8 micron; Preferably, The mineral fibers are selected from calcium sulfate fibers.
8. The antistatic polyamide composition according to any one of claims 1-7, characterized in that the volume resistivity of the antistatic polyamide composition is less than or equal to 9.9×10 ⁸ ohm·cm.
9. According to the preparation method of the antistatic polyamide composition described in any one of claims 1-8, it is characterized in that, according to the proportion, the polyamide resin and nanostructured carbon are mixed evenly, and then the main feed of the twin-screw extruder is added The isotropic pitch-based carbon fiber is fed into the twin-screw extruder through the first side feeder, and the mineral fiber is added into the twin-screw extruder through the second side feeder, melt-extruded and granulated to obtain the anti- Electrostatic polyamide composition; wherein, the rotational speed range of the screw is 200-500rpm, the aspect ratio is 40:1-48:1, and the temperature range is 270-320°C.
10. The application of the antistatic polyamide composition according to any one of claims 1-8, characterized in that it is used to prepare camera module components.