CN111500062B - Antistatic heat-aging-resistant polyamide composite material and preparation method and application thereof - Google Patents

Abstract

The invention discloses an antistatic heat-aging-resistant polyamide composite material which comprises the following components in parts by weight: 27-100 parts of polyamide resin; 0.3-10 parts of carbon nano tubes; 0-60 parts of reinforcing filler; 0.05-3 parts of secondary amine compound; 0.05-2 parts of inorganic phosphate. The antistatic heat-resistant aging polyamide composition provided by the invention has the surface resistivity as low as 105, and the retention rate of unnotched impact strength after 150 ℃/250h of thermal oxidation aging can be as high as 92%, so that the application field of the polyamide composite material is greatly expanded.

Description

A kind of antistatic heat aging resistant polyamide composite material and its preparation method and application

technical field

The invention relates to the technical field of polymer material modification, in particular to a carbon nanotube-filled modified polyamide composite material with excellent heat aging resistance and antistatic performance, and a preparation method and application thereof.

Background technique

With the rapid development of automobile lightweight process, the scope of application of non-metal products is also expanding, of which the most widely used is plastic products, the application of plastic has been extended from interior decoration to parts and components, "replacing steel with plastic" , "Replacing aluminum with plastic" has become a trend.

Polyamide resin in plastics is widely used in various parts of automobiles because of its good heat resistance, high temperature and external high and low temperature changes caused by the operation of automobile engines, and excellent aging resistance and wear resistance. Especially heat-resistant functional parts under the hood and gas and oil pipelines. As auto parts, especially those used around the engine, it is easy to generate static electricity due to motion friction and induction. If the generated static electricity cannot be eliminated in time, when it accumulates to a certain amount, it will cause dust absorption, electric shock, and even fire after sparks are generated. , explosion and other safety hazards, for this reason, many auto parts have antistatic requirements for their materials. But as we all know, polyamide resin is an excellent insulating material, and its surface resistivity is usually 1014-1016Ω, and only when the surface resistivity of polyamide reaches 108-1010Ω, it has antistatic properties. Therefore, in order to avoid the accumulation of static electricity when polyamide products are used as much as possible, it is necessary to carry out antistatic modification of polyamide to endow it with lower surface resistivity and eliminate static electricity hazards.

Furthermore, as a polyamide composite material for the peripheral parts of the automobile engine, it must not only have good antistatic performance, but also have good heat aging resistance, especially the unnotched impact strength cannot decay too quickly, because the engine peripheral Parts need to be exposed to high temperature environment during their service life, and they are in a state of vibration for a long time during work. If the impact performance decays too quickly, it will directly cause the parts to fail early before their normal service life. The recall of all problematic vehicles not only brings inconvenience and worry to car consumers, but also brings huge economic losses to car manufacturers. Therefore, it is very necessary to research and develop polyamide composite materials with antistatic and heat aging resistance properties, which has great practical significance.

At present, the most commonly used method to improve the antistatic performance of polyamide materials is to add conductive filler antistatic agents, such as metal fibers, carbon fibers, carbon black, carbon nanotubes, etc. However, metal fiber and carbon fiber have disadvantages such as high addition amount, high price, and large fluctuation of surface resistivity, which restrict their application; carbon black needs to be added in large quantities due to low conductivity, which will easily lead to the decline of physical and mechanical properties of nylon resin, and the decline of fluidity. Carbon nanotubes are one-dimensional nanomaterials with excellent mechanical properties and electrical conductivity. They are used to replace carbon black to improve the antistatic properties of polyamides. The influence is small, and even a slight enhancement can be achieved within a certain range, and the surface resistivity is relatively more stable.

The present inventor uses carbon nanotubes to fill the modified polyamide. Although the obtained composite material meets the antistatic performance requirements, its heat aging resistance is not ideal, and it needs to be modified. However, after a large number of experimental verifications, it is surprising It was found that using the technical means of improving the heat aging resistance of polyamides recognized in the art—adding heat stabilizers such as copper compounds/halogen compounds did not improve the heat aging resistance of carbon nanotubes/polyamide-based composites. Satisfactory, especially the unnotched impact strength attenuation is too fast, the specific performance is that the unnotched impact strength retention rate after 150°C/250h heat aging is only 40%.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a carbon nanotube filled modified polyamide composite material with excellent heat aging resistance and antistatic performance, the carbon nanotube filled modified polyamide composite material in While having good antistatic performance, it also has good heat aging resistance. After heat aging at 150°C for 250 hours, the retention rate of unnotched impact strength can be maintained at about 90%.

The object of the present invention is achieved through the following technical solutions:

An antistatic, heat-resistant and aging-resistant polyamide composite material comprises the following components in parts by weight:

The polyamide resin is selected from PA6, PA11, PA12, PA46, PA66, PA610, PA612, PA1010, PA1012, PA1212, PA4T, PA6T, PA9T, PA10T, PA6I, MXD6, PA66/6, PA6T/6I, PA6T/66 One or more of them; PA6, PA46, PA66, PA610, PA66/6, PA6T/66 are preferred.

The reinforcing filler is selected from fiber filler, inorganic mineral powder or a compound of fiber filler and inorganic mineral powder.

The fiber filler is selected from one or more of glass fiber, carbon fiber, basalt fiber and potassium titanate fiber.

The inorganic mineral powder is selected from one or more of talcum powder, wollastonite, mica, calcium carbonate, attapulgite, montmorillonite, zeolite and kaolin.

The secondary amine compound is selected from one or more of fully aromatic secondary amine compounds, semiaromatic secondary amine compounds and aliphatic secondary amine compounds.

Preferably, the secondary amine compound is a fully aromatic secondary amine compound and/or a semi-aromatic secondary amine compound, preferably N,N'-diphenyl-p-phenylenediamine, N-(1-3-dimethylbutylene base)-N'-phenyl-p-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, N-phenyl-1-naphthylamine, N-phenyl-2 -naphthylamine, octylated diphenylamine, 4,4'-dioctyl diphenylamine, 4,4'-di(phenylisopropyl)diphenylamine, N,N'-bis(β-naphthyl)-p- Phenylenediamine, N,N'-di-isooctyl-p-phenylenediamine, N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, N-phenyl-N'-cyclo One or more of hexyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, and N-isohexyl-N'-phenyl-p-phenylenediamine.

The inorganic phosphate is selected from potassium phosphate, sodium phosphate, calcium phosphate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, calcium dihydrogen phosphate, dipotassium hydrogen phosphate, disodium hydrogen phosphate, calcium hydrogen phosphate, potassium pyrophosphate, pyrophosphate One or more of sodium phosphate and calcium pyrophosphate.

After a large number of experiments, it was found that in the carbon nanotube/polyamide system, a small amount of secondary amine compound and inorganic phosphate were introduced, which endowed the polyamide material with excellent antistatic performance and heat aging resistance, and the obtained carbon nanotube filled modified The surface resistivity of the polyamide composite material can be as low as 105, and the unnotched impact strength retention rate after 150°C/250h thermal oxygen aging can be as high as 92%, which greatly broadens the application field of the polyamide composite material.

As a preference, the antistatic heat aging resistant polyamide composite material includes the following components in parts by weight:

Further preferably, the antistatic, heat-resistant and aging-resistant polyamide composite material includes the following components in parts by weight:

Preferably, the copper salt heat stabilizer is selected from one or more of cuprous halides, inorganic copper salts, copper carboxylate salts, and copper salt complexes.

It has been found through experiments that the copper salt heat stabilizer has almost no effect on improving the heat aging resistance of the carbon nanotube/polyamide system, and after introducing a small amount of secondary amine compound and inorganic phosphate, the prepared carbon nanotube filled improved The heat aging resistance of the permanent polyamide-based composite material has been significantly improved, and the unnotched impact strength retention rate after 150°C/250h thermal oxygen aging has been directly increased from the original 40% to 90%.

As a preference, the antistatic heat aging resistant polyamide composite material includes the following components in parts by weight:

Wherein, the reinforcing material is composed of 1-5 parts of carbon fiber and 10-40 parts of other reinforcing material; the other reinforcing material is glass fiber or/and inorganic mineral powder.

It was found through tests that the carbon nanotube-filled modified polyamide composite material obtained by using this formula system not only has excellent heat aging resistance, comprehensive mechanical properties and antistatic properties, but also has almost no fluctuation in the surface resistivity value of the composite material. The antistatic performance is more stable, which is very suitable for the peripheral parts of automobile engines with high requirements on the stability of antistatic performance and comprehensive mechanical properties, and it is more guaranteed for the safety of automobile use.

Further preferably, the antistatic, heat-resistant and aging-resistant polyamide composite material includes the following components in parts by weight:

It has been found through tests that the carbon nanotube-filled modified polyamide composite material obtained by using this formula system can not only ensure excellent heat aging resistance, comprehensive mechanical and antistatic properties, but also have excellent dimensional molded products. The stability and apparent flatness further enhance the competitiveness of the product.

The present invention also provides a preparation method for the above-mentioned antistatic heat-resistant aging polyamide composite material, which includes the following steps: premixing other components except fiber fillers, and feeding from the main feeding port; The material is discharged from the feeding port, and extruded and granulated by the screw extruder.

The above-mentioned antistatic, heat-resistant and aging polyamide composite materials are used in parts under the engine hood, charge air cooler, oil pan, thermostat, cylinder head, resonator, muffler, intake manifold, throttle valve, catalytic converter Applications in automotive parts such as housings, intercooler intake ports, and engine cooling systems.

Compared with prior art, the present invention has following advantage:

The present invention introduces carbon nanotubes, secondary amine compounds and inorganic phosphates into the polyamide resin matrix, and uses the synergistic effect of the three materials of carbon nanotubes/secondary amine compounds/inorganic phosphates to form an excellent antistatic/heat-resistant The aging synergistic system endows the polyamide composite with good antistatic performance and excellent heat aging resistance. The prepared antistatic and heat-resistant aging polyamide composite material has a low surface resistivity (105-1010Ω), and after heat aging at 150°C for 250 hours, its unnotched impact strength retention rate can reach about 90%, which is very suitable for high heat-resistant Structural or functional parts around automobile engines with high vibration strength and high impact strength required by aging performance broaden the application field of polyamide materials.

Detailed ways

The present invention will be further described below through specific implementation methods. The following examples are preferred implementation forms of the present invention. Those skilled in the art can analyze and understand the various examples and combine the existing knowledge with the technical solutions provided by the present invention. A series of deformations and equivalent replacements are made, and the new technical solutions obtained by the deformations and equivalent replacements are also included in the present invention.

In order to enable readers to better understand the gist of the present invention, a series of the most representative experimental data are given as examples. Readers should have general technical knowledge in this field when reading, so as to facilitate and accurately understand the logical relationship contained in the data.

The raw materials used in the examples and comparative examples are now described as follows, but not limited to these materials:

PA66 resin: EPR27, Pingdingshan Shenma Engineering Plastics Co., Ltd.;

PA6 resin: M2400, Guangdong Xinhui Meida Nylon Co., Ltd.;

PA6T/66 resin: N-600, Zhejiang NHU Co., Ltd.;

Glass fiber: ECS-301CL-4.5, Chongqing International Composite Materials Co., Ltd.;

Carbon fiber: ZOLTEK ^TM PX35, Japan Toray Industries Co., Ltd.;

Mica: PW30, LKAB company;

Carbon nanotube 1: FT-7001, Jiangsu Tiannai Material Technology Co., Ltd.

Carbon nanotube 2: GT-300, Shandong Dazhan Nanomaterials Co., Ltd.

Secondary amine compound 1: N,N'-diphenyl-p-phenylenediamine, American Chemtura

Secondary amine compound 2: N-(1-3-dimethylbutyl)-N’-phenyl-p-phenylenediamine, American Chemtura

Secondary amine compound 3: 2,2,4-trimethyl-1,2-dihydroquinoline polymer, Chemtura, USA

Inorganic phosphate 1: Calcium phosphate, analytically pure, Tianjin Jinhui Taiya Chemical Reagent Co., Ltd.

Inorganic phosphate 2: sodium dihydrogen phosphate, analytically pure, Tianjin Jinhui Taiya Chemical Reagent Co., Ltd.

Inorganic phosphate 3: Dipotassium hydrogen phosphate, analytically pure, Tianjin Jinhui Taiya Chemical Reagent Co., Ltd.

Hindered phenol antioxidant: 1098, BASF

Copper salt heat stabilizer: H318, Bruggemann, Germany

Lubricant: TAF, Suzhou Xingtai Photochemical Auxiliary Company

The parts by weight of the raw materials used in the following examples and comparative examples are shown in Table 1 and Table 2 respectively.

The following examples and comparative examples adopt the same preparation method, and the specific steps include: the examples and the comparative examples are respectively according to the proportions by weight described in Table 1 and Table 2, and the other components except the fiber filler are first mixed uniformly , and then use a twin-screw extruder to extrude and granulate. The aspect ratio of the twin-screw extruder is 40:1, the screw speed is 280r/min, and the strands are water-cut and pelletized. After the particles are dried (usually baked in a vacuum oven at 80° C. for 5 to 8 hours), the standard specimens corresponding to the test are molded in an injection molding machine, and the performance test is carried out. The performance test results of the examples and comparative examples are shown in Table 1 and Table 2 respectively. .

Thermal aging performance evaluation: According to ISO179-1, prepare a test sample with a length of 80mm, a width of 10mm, and a thickness of 4mm by molding, and test the unnotched impact strength before and after aging (test results of at least 10 samples of the same composition and shape The average value of the average value), hot air aging using a thermal aging box, adjust the temperature to 150 ° C, after reaching 250 hours, the sample is taken out of the aging box, and after cooling to room temperature, it is heat-sealed with an aluminum foil bag to prevent any absorption before evaluating the mechanical properties. moisture. Compared with the corresponding mechanical properties before aging, the retention rate of unnotched impact strength was calculated and expressed as a percentage.

Surface resistivity test method: test according to IEC60093 standard, sample size φ100×3mm.

Test method of unnotched impact strength: test according to ISO 179 standard, sample size is 55×6×4mm.

Table 1 Embodiment 1～13 polyamide composite material formula and performance test result (weight part)

Table 2 Comparative Examples 1-11 polyamide composite formulation and performance test results (parts by weight)

From the performance test results of Examples 1 to 13 in Table 1 and Comparative Examples 1 to 11 in Table 2, it can be clearly seen that the present invention introduces a small amount of secondary amine compound and inorganic phosphate into the carbon nanotube/polyamide system. , can significantly improve the long-term heat aging resistance of polyamide composite materials, and the unnotched impact strength retention rate after 150°C/250h heat aging is very high (about 90%), and unexpected technical effects have been achieved. And the secondary amine compound and inorganic phosphate are only helpful to the improvement of the thermal aging resistance of the carbon nanotube/polyamide system, and have almost no effect on the improvement of the thermal aging resistance of the carbon nanotube-free system (Comparative Example 10). Inorganic phosphate used alone in the carbon nanotube/polyamide system (Comparative Example 9) cannot improve its thermal aging resistance. And add conventional copper salt thermal stabilizer (comparative example 2, comparative example 5 and comparative example 7) alone, or add copper salt thermal stability and hindered phenolic antioxidant (comparative example 3), to improving carbon nanotube/polyamide The heat aging resistance of the system has almost no contribution, and the unnotched impact strength retention rate is only about 40% after 150°C/250h, compared with the carbon nanotube/polyamide system without any heat stabilizer (comparative example 1 and comparative example 6 ) have comparable thermal aging resistance.

Though above-mentioned embodiment has done more detailed text description to the design idea of the present invention, these text descriptions are only the simple text description to the design idea of the present invention, rather than the restriction to the design idea of the present invention, any not exceeding the combination of the design idea of the present invention, Additions or modifications all fall within the protection scope of the present invention.

Claims (9)

1. An antistatic heat-resistant aging polyamide composite material is characterized in that, by weight, it comprises the following components: 27~100 parts of polyamide resin; 0.3~10 parts of carbon nanotubes; Reinforcing filler 0 ~ 60 parts; Secondary amine compound 0.05~3 parts; Inorganic phosphate 0.05~2 parts; The secondary amine compound is selected from N,N'-diphenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 2,2,4- Trimethyl-1,2-dihydroquinoline polymer, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, octylated diphenylamine, 4,4'-dioctyldi Aniline, 4,4'-di(phenylisopropyl)diphenylamine, N,N'-bis(β-naphthyl)-p-phenylenediamine, N,N'-di-isooctyl-p-phenylenediamine, N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, N-phenyl-N'-cyclohexyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine One or more of diamine, N-isohexyl-N'-phenyl-p-phenylenediamine; The inorganic phosphate is selected from one or more of potassium phosphate, sodium phosphate, calcium phosphate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, calcium dihydrogen phosphate, dipotassium hydrogen phosphate, disodium hydrogen phosphate, calcium hydrogen phosphate ; The carbon nanotubes are selected from FT-7001 of Jiangsu Tiannai Material Technology Co., Ltd. or GT-300 of Shandong Dazhan Nano Material Co., Ltd. 2. The antistatic heat-resistant aging polyamide composite material according to claim 1, wherein the polyamide resin is selected from the group consisting of PA6, PA11, PA12, PA46, PA66, PA610, PA612, PA1010, PA1012, PA1212, One or more of PA4T, PA6T, PA9T, PA10T, PA6I, MXD6, PA66/6, PA6T/6I, PA6T/66. 3. The antistatic heat-resistant aging polyamide composite material according to claim 1, wherein the reinforcing filler is selected from fiber filler, inorganic mineral powder or a compound of fiber filler and inorganic mineral powder. 4. antistatic heat-resistant aging polyamide composite material according to claim 3, is characterized in that, described fiber filler is selected from one or more in glass fiber, carbon fiber, basalt fiber, potassium titanate fiber; The inorganic mineral powder is selected from one or more of talcum powder, wollastonite, mica, calcium carbonate, attapulgite, montmorillonite, zeolite and kaolin. 5. The antistatic heat-resistant aging polyamide composite material according to any one of claims 1 to 4, wherein, in parts by weight, it comprises the following components: 40~100 parts of polyamide resin; 0.3~5 parts of carbon nanotubes; Reinforcing material 5~60 parts; Secondary amine compound 0.05~2 parts; Inorganic phosphate 0.05~1 part. 6. antistatic heat-resistant aging polyamide composite material according to claim 5, is characterized in that, by weight, comprises the following components: 40~100 parts of polyamide resin; 0.3~5 parts of carbon nanotubes; Reinforcing material 5~60 parts; Secondary amine compound 0.05~1 part; Inorganic phosphate 0.05~1 part; Copper salt heat stabilizer 0.05~1 part. 7. antistatic heat-resistant aging polyamide composite material according to claim 6, by weight, comprises the following components: 45~100 parts of polyamide resin; 0.3~5 parts of carbon nanotubes; Reinforcing material 10~45 parts; Secondary amine compound 0.05~1 part; Inorganic phosphate 0.05~0.5 parts; Copper salt heat stabilizer 0.05~1 part; Wherein, the reinforcing material is composed of 1-5 parts of carbon fiber and 10-40 parts of other reinforcing materials; the other reinforcing materials are glass fibers or/and inorganic mineral powder. 8. antistatic heat-resistant aging polyamide composite material according to claim 7, by weight, comprises the following components: 45~100 parts of polyamide resin; 0.3~5 parts of carbon nanotubes; Glass fiber 1~30 parts; Inorganic mineral powder 1~10 parts; Carbon fiber 1~5 parts; Secondary amine compound 0.05~1 part; Inorganic phosphate 0.05~0.5 parts; Copper salt heat stabilizer 0.05~1 part. 9. The application of the antistatic heat-resistant aging polyamide composite material according to any one of claims 1 to 8, wherein the antistatic heat-resistant aging polyamide composite material is used in auto parts: pressurized air cooling Applications in the radiator, oil pan, thermostat, cylinder head, resonator, muffler, intake manifold, throttle valve, catalytic converter housing, engine cooling system.