A heat-resistant and oxidation-resistant polypropylene composite material, its preparation method and application

Abstract

The present invention discloses a heat-resistant and oxidation-resistant polypropylene composite material, a preparation method thereof and an application. The heat-resistant and oxidation-resistant polypropylene composite material of the present invention comprises the following components: polypropylene resin, a laser marking composite, a primary antioxidant and a secondary antioxidant; the laser marking composite comprises an ABS resin and multi-walled carbon nanotubes, and the mass ratio of the ABS resin to the multi-walled carbon nanotubes is (10-30):(70-90). The present invention combines the ABS resin with multi-walled carbon nanotubes to form a laser marking composite, and uses the multi-walled carbon nanotubes to improve the laser absorption capacity of the polypropylene composite material. By combining the photothermal conversion effect of the ABS resin and the axial heat conduction effect of the multi-walled carbon nanotubes, not only can the laser marking efficiency be enhanced to improve the laser marking performance, but also the heat-resistant and oxidation-resistant performance of the polypropylene composite material can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of compositions of polymer compounds, and more specifically, to a heat-resistant and oxidation-resistant polypropylene composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Due to its good chemical resistance, insulation property, and excellent mechanical properties, polypropylene is applied in fields such as electronics and electrical appliances. Taking household appliances as an example, it is often necessary to carry out marking or decoration on their surfaces to improve their recognition and ornamental value. Compared with traditional ink jet coding, laser marking technology has characteristics such as fast marking and high freedom, and is widely used in the marking and decoration of plastic products. However, polyolefins represented by polypropylene are difficult to form clear laser marks because they cannot effectively absorb laser of corresponding wavelengths.

[0003] Currently, the marking effect of polyolefins is mainly improved by adding a large amount of marking aids. Commonly used marking aids are mostly composed of metal oxides, acetylene carbon black, etc. For example, a laser-markable polypropylene plastic is disclosed in the prior art. Mica flakes modified with copper oxide and antimony trioxide are used as laser absorbers, combined with specific black pigments to form a marking aid, and the heat absorption effect of the oxide and the role of the mica flakes in reflecting laser beams are used to improve the laser marking effect; however, this marking aid will induce and accelerate the aging of polypropylene during long-term heat-oxygen aging, thereby reducing the service life of the polypropylene material. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects and deficiencies that existing polypropylene composite materials are difficult to have both good marking performance and heat-resistant and oxidation-resistant performance, and to provide a heat-resistant and oxidation-resistant polypropylene composite material.

[0005] Another purpose of the present invention is to provide a preparation method of a heat-resistant and oxidation-resistant polypropylene composite material.

[0006] Another purpose of the present invention is to provide an application of a heat-resistant and oxidation-resistant polypropylene composite material in automotive marking parts or electronic product casings.

[0007] Another purpose of the present invention is to provide an electronic product casing.

[0008] The above purposes of the present invention are achieved by the following technical solutions:

[0009] The present invention protects a heat-resistant and oxidation-resistant polypropylene composite material, which comprises the following components in parts by weight:

[0010] 100 parts of polypropylene resin, 0.03 - 0.1 part of laser marking composite, 0.1 - 0.5 part of primary antioxidant, 0.1 - 0.5 part of secondary antioxidant; the laser marking composite includes ABS resin and multi-walled carbon nanotubes, and the mass ratio of the ABS resin to the multi-walled carbon nanotubes is (10 - 30):(70 - 90).

[0011] In the present invention, an ABS resin and multi-walled carbon nanotubes are combined to form a laser marking composite. The multi-walled carbon nanotubes are used to improve the laser absorption ability of the polypropylene composite material. Combining the photothermal conversion effect of the ABS resin and the axial heat conduction effect of the multi-walled carbon nanotubes can not only enhance the laser marking efficiency to improve the laser marking performance; at the same time, it can also enable the heat in the polypropylene composite material during the long-term thermo-oxidative aging process to be rapidly conducted along the axis of the multi-walled carbon nanotubes to prevent the radial diffusion of heat to play a role in protecting the resin matrix, thereby improving the heat-resistant and oxygen-aging performance of the polypropylene composite material.

[0012] Preferably, the heat-resistant and oxygen-aging polypropylene composite material includes the following components by weight:

[0013] 100 parts of polypropylene resin, 0.05 - 0.08 part of laser marking composite, 0.1 - 0.5 part of primary antioxidant, 0.1 - 0.5 part of secondary antioxidant.

[0014] Optionally, the mass ratio of the ABS resin to the multi-walled carbon nanotubes in the laser marking composite can specifically be 15:85, 20:80, 25:75, 30:70; preferably (10 - 20):(80 - 90).

[0015] Optionally, the laser marking composite can be prepared by the following method:

[0016] The ABS resin solution and the multi-walled carbon nanotubes are ultrasonically mixed and the solvent is removed to obtain the laser marking composite; the ABS resin solution includes an ABS resin and an organic solvent.

[0017] Optionally, the polypropylene resin is measured to have a melt mass flow rate of 1 - 60 g / 10 min at 230 °C and 2.16 kg according to the ISO 1133-2022 standard, and specifically can be 5 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min or 55 g / 10 min.

[0018] Optionally, the acrylonitrile (AN) content in the ABS resin is 20% to 25%, specifically, it can be 20%, 21%, 22%, 23%, 24% or 25%; the calculation formula of the AN content: AN(%) = 25.16 / (104.14X + 8.67), where X is A 1600cm-1 / A 2237cm-1 (absorbance at 1600 cm -1 absorbance ratio to the absorbance at 2237 cm -1 ).

[0019] Specifically, the primary antioxidant is at least one of hindered phenol antioxidants; and / or the co-antioxidant is at least one of phosphite antioxidants.

[0020] The present invention also protects a preparation method of the above heat-resistant and oxidation-resistant polypropylene composite material, which includes the following steps: mixing and melt-extruding each component to obtain the heat-resistant and oxidation-resistant polypropylene composite material.

[0021] Specifically, a twin-screw extruder can be used for melt-extrusion in the above preparation method, and the temperature of melt-extrusion is 210°C to 230°C.

[0022] The application of the above heat-resistant and oxidation-resistant polypropylene composite material in automotive marking parts or electronic product housings is also within the protection scope of the present invention.

[0023] The present invention also protects a housing of an electronic product made of the above heat-resistant and oxidation-resistant polypropylene composite material, and the housing generates laser marks through laser marking.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] In the present invention, an ABS resin is combined with multi-walled carbon nanotubes to form a laser marking composite. The multi-walled carbon nanotubes are used to improve the laser absorption ability of the polypropylene composite material. Combining the photothermal conversion effect of the ABS resin and the axial heat conduction effect of the multi-walled carbon nanotubes can not only enhance the laser marking efficiency to improve the laser marking performance; at the same time, it can also enable the heat in the polypropylene composite material to be rapidly conducted along the axis of the multi-walled carbon nanotubes during the long-term heat-resistant and oxidation-resistant process, so as to prevent the radial diffusion of heat to play a role in protecting the resin matrix, thereby improving the heat-resistant and oxidation-resistant performance of the polypropylene composite material. Specific Embodiments

[0026] The following further illustrates the present invention in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw material reagents used in the embodiments of the present invention are conventionally purchased raw material reagents.

[0027] 1. Raw Material Reagents

[0028] PP-1, with a melt mass flow rate of 30 g / 10 min, grade PP PPH-Y26, manufacturer: Sinopec;

[0029] PP-2, with a melt mass flow rate of 12 g / 10 min, grade HP500N, manufacturer: CNOOC and Shell;

[0030] ABS-1, with an AN content of 25%, grade DG-417, manufacturer: Tianjin Dagu Chemical Industry Co., Ltd.;

[0031] ABS-2, with an AN content of 20%, grade GP-22, manufacturer: Ineos Styrolution;

[0032] Multi-walled carbon nanotubes, acetylene black, single-walled carbon nanotubes and double-walled carbon nanotubes are all commercially available;

[0033] The main antioxidant is SONOX 1010, and the co-antioxidant is SONOX 168, both of which are commercially available.

[0034] 2. The laser marking composite of the present invention can be prepared by the following preparation method:

[0035] Dissolve the ABS resin in dichloromethane to form an ABS solution, then add carbon nanotubes or acetylene black to the ABS solution, ultrasonically mix at room temperature for 1 - 2 h, and then remove dichloromethane by rotary evaporation to obtain different laser marking composites; among them, the weight parts of the ABS resin and carbon nanotubes or acetylene black in the laser marking composite are shown in Table 1.

[0036] Table 1 Laser marking composites 1 - 9

[0037]

[0038]

[0039] 3. The heat-resistant oxygen-aged polypropylene composite materials of the examples and comparative examples of the present invention are prepared by the following preparation method:

[0040] Weigh each component according to the formula, mix them evenly, and then add them to a twin-screw extruder for melt blending and extrusion granulation to obtain the heat-resistant oxygen-aged polypropylene composite material; among them, the melting and extrusion temperature of the twin-screw extruder is 220 °C.

[0041] 4. Performance testing

[0042] (1) Laser marking test: After the heat-oxidative aging-resistant polypropylene composite materials in each embodiment and comparative example were dried in a blast oven at 80°C for 2 hours, they were respectively added to an injection molding machine for injection molding into a color plate with a size of 83 mm*54 mm*2 mm and smooth on both sides; the color plate was then marked using a Han's Laser EP12 infrared marking machine (red light wavelength 1064 nm, marking process: frequency 24 kHz, current 16 A); then a Datacolor 1050 colorimeter was used to measure the L, a, and b values ​​of the color plate before and after marking under the SCI mode UVD65 light source, and the color difference ΔE before and after marking was calculated according to the CIE 1976 color difference formula.

[0043] (2) Thermal oxygen aging test: Accelerate thermal aging at 130°C, observe whether there are any abnormal appearances such as powdering and cracking on the surface, and record the time when powdering or cracking occurs; the time when powdering or cracking occurs is used to evaluate the thermal oxygen aging resistance of the polypropylene composite material. The longer the time when powdering or cracking occurs, the better the thermal oxygen aging resistance of the polypropylene composite material.

[0044] Examples 1 to 8 and Comparative Examples 1 to 7

[0045] The weight proportions of the components in the heat-oxidative aging-resistant polypropylene composite materials in Examples 1 to 8 and Comparative Examples 1 to 7 are shown in Tables 2 and 3.

[0046] Table 2 Weight fractions of each component in the heat-oxidative aging-resistant polypropylene composite material in Examples 1 to 8

[0047]

[0048]

[0049] Table 3 Weight fractions of each component in the heat-oxidative aging-resistant polypropylene composite material in Comparative Examples 1 to 7

[0050] Comparative Example 1 2 3 4 5 6 7 PP-1 100 100 100 100 100 100 100 Laser Marking Composite 1 / / / / 0.01 / / Laser Marking Composite 5 / / / / / 0.05 / Laser Marking Composite 6 / / / / / / 0.05 Laser Marking Composite 7 0.05 / / / / / / Laser Marking Composite 8 / 0.05 / / / / / Laser Marking Composite 9 / / 0.05 / / / / ABS-1 / / / 0.005 / / / Multi-Walled Carbon Nanotubes / / / 0.045 / / / Primary Antioxidant 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Secondary Antioxidant 0.2 0.2 0.2 0.2 0.2 0.2 0.2

[0051] The performance test results of the heat-oxidative aging-resistant polypropylene composite materials in each embodiment and comparative example according to the above-mentioned method are shown in Table 4.

[0052] Table 4 Test results of heat-oxidative aging-resistant polypropylene composite materials in various embodiments and comparative examples

[0053]

[0054]

[0055] According to the data in Table 4, it can be seen that the color difference △E of the heat-resistant and oxidation-resistant polypropylene composites in Examples 1 to 8 all reached more than 30, and at the same time, the time when powdering or cracking occurred during accelerated heat aging at 130 °C was greater than or equal to 576 h, indicating that the heat-resistant and oxidation-resistant polypropylene composites of the present invention not only have good laser marking performance, but also have excellent heat-resistant and oxidation-resistant performance.

[0056] In addition, it can be seen from Comparative Examples 1, 2, and 3 that although acetylene black, single-walled carbon nanotubes or double-walled carbon nanotubes have a certain improvement effect on the marking performance and heat-resistant and oxidation-resistant performance of polypropylene composites, the improvement effect is limited.

[0057] According to Comparative Example 4, it was found that when ABS and multi-walled carbon nanotubes were directly added to the polypropylene resin, due to the poor dispersibility of ABS and multi-walled carbon nanotubes in the system, it was difficult for ABS and multi-walled carbon nanotubes to play a synergistic role, resulting in poor laser marking performance of the polypropylene composite.

[0058] It can be seen from Example 1, Comparative Example 5, Comparative Example 6, and Comparative Example 7 that when the amount of the laser marking composite in the system is small, or the ratio of multi-walled carbon nanotubes and ABS is small, it is difficult to achieve the technical effects of the present invention.

[0059] The above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A heat-resistant and oxidation-resistant polypropylene composite material, characterized in that, By weight parts, it comprises the following components: 100 parts of polypropylene resin, 0.03 - 0.1 part of laser marking composite, 0.1 - 0.5 part of primary antioxidant, 0.1 - 0.5 part of secondary antioxidant; The laser marking composite comprises ABS resin and multi - walled carbon nanotubes, and the mass ratio of the ABS resin to the multi - walled carbon nanotubes is (10 - 30):(70 - 90); The laser marking composite is prepared by the following method: ultrasonically mixing the ABS resin solution and the multi - walled carbon nanotubes and removing the solvent to obtain the laser marking composite; The acrylonitrile content in the ABS resin is 20% - 25%.

2. The heat-resistant and oxidation-resistant polypropylene composite material according to claim 1, wherein By weight parts, it comprises the following components: 100 parts of polypropylene resin, 0.05 - 0.08 part of laser marking composite, 0.1 - 0.5 part of primary antioxidant, 0.1 - 0.5 part of secondary antioxidant.

3. The heat-resistant and oxidation-resistant polypropylene composite material according to claim 1, wherein The mass ratio of the ABS resin to the multi - walled carbon nanotubes is (10 - 20):(80 - 90).

4. The heat-resistant and oxidation-resistant polypropylene composite material according to claim 1, wherein The ABS resin solution comprises ABS resin and organic solvent.

5. The heat-resistant and oxidation-resistant polypropylene composite material according to claim 1, wherein The polypropylene resin is measured to have a melt mass - flow rate of 1 - 60 g / 10 min at 230 °C and 2.16 kg according to the ISO 1133 - 2022 standard.

6. The heat-resistant and oxidation-resistant polypropylene composite material according to claim 1, wherein The primary antioxidant is at least one of hindered phenol antioxidants; and / or the secondary antioxidant is at least one of phosphite antioxidants.

7. A method for preparing the heat-resistant and oxidation-resistant polypropylene composite material according to any one of claims 1 to 6, characterized in that, It comprises the following steps: mixing the components and melt - extruding to obtain the heat - resistant and oxidation - aging polypropylene composite material.

8. Application of the heat - resistant and oxidation - aging polypropylene composite material according to any one of claims 1 - 6 in automotive marking parts or electronic product housings.

9. A housing of an electronic product made of the heat-resistant and oxidation-resistant polypropylene composite material according to any one of claims 1 to 6, characterized in that, The housing generates laser marks through laser marking.

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