Polycarbonate composition as well as preparation method and application thereof

Abstract

The invention discloses a polycarbonate composition as well as a preparation method and application thereof. The polycarbonate composition is prepared from the following components in parts by weight: 50 to 80 parts of polycarbonate; 20 to 50 parts of siloxane polycarbonate; 0.3 to 2 parts of a triazine ultraviolet light absorber; 0.1 to 0.8 part of a hindered phenol antioxidant; 0.1 to 0.5 part of yellow toner; the yellow toner is selected from at least one of azo yellow, quinophthalone yellow or isoindolinone yellow. According to the polycarbonate composition disclosed by the invention, through the synergistic effect of the hindered phenol antioxidant and the triazine ultraviolet absorber, the photooxidative degradation of a polycarbonate matrix is radically retarded; meanwhile, specific yellow toner is added and can be controllably and moderately degraded under long-term UVB irradiation, and the yellow variable of a matrix is made up macroscopically, so that the chromatic aberration change of the whole material system after long-term UVB aging is effectively reduced, excellent color stability is shown, and meanwhile, the mechanical property stability and the light transmittance stability of the material are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a polycarbonate composition, its preparation method, and its application. Background Technology

[0002] Polycarbonate (PC) has become a preferred material for some transparent parts due to its excellent mechanical properties, high transparency, and good processability. For some exterior parts that operate in outdoor environments (such as key components like headlight covers and dashboard covers for two-wheeled electric vehicles), which need to be continuously exposed to ultraviolet radiation for a long time, the carbonate bonds in the PC molecular chain are extremely sensitive to ultraviolet light (especially the UVB band of 290-320nm). Under long-term outdoor exposure, it is prone to photo-oxidation and Fries rearrangement reactions, leading to yellowing, decreased light transmittance, and deterioration of mechanical properties, which seriously affects the appearance quality and service life.

[0003] With the rapid development of the outdoor products market and the increasing demands of consumers for product quality, the industry has placed higher requirements on the color stability and performance retention of PC materials under UVB aging conditions. Although existing technologies, such as patent WO2024210563A1, propose an improved solution using siloxane copolymerized polycarbonate (Si-PC) in combination with triazine UV absorbers, in actual use environments requiring long-term, harsh UVB irradiation, existing solutions still struggle to meet the extreme pursuit of long-term color stability in such application scenarios. Especially in the high-end two-wheeled electric vehicle sector, the color consistency of transparent components directly affects the product's aesthetics and brand image; any perceptible color change will reduce the product's market competitiveness.

[0004] Therefore, developing a polycarbonate composition that can maintain excellent color stability and mechanical properties under long-term UVB irradiation is key to driving technological upgrades in the industry and meeting market demands. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a polycarbonate composition that is resistant to UV aging and has excellent color stability.

[0006] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a polycarbonate composition comprising, by weight parts: 50-80 parts polycarbonate; 20-50 parts of siloxane polycarbonate; 0.3-2 parts of triazine ultraviolet absorber; 0.1-0.8 parts of hindered phenolic antioxidants; 0.1-0.5 parts of yellow pigment; The yellow pigment is selected from at least one of azo yellow, quinoline yellow, or isoindolinone yellow.

[0007] The polycarbonate may be in parts by weight of 50, 55, 60, 65, 70, 75 or 80 parts, or specific parts between the above values.

[0008] Preferably, the polycarbonate has a number-average molecular weight of 18,000-32,000. The number-average molecular weight is determined using gel permeation chromatography (GPC).

[0009] The polycarbonate composition contains 50%-80% polycarbonate by weight.

[0010] The weight percentage of the siloxane polycarbonate can be 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, or 50 parts, as well as specific values ​​between the above-mentioned values.

[0011] Preferably, the silicon content of the siloxane polycarbonate is 6%-10%. The silicon content is determined by the intensity of the SI-O peaks in a 1H NMR spectrum.

[0012] Preferably, the triazine ultraviolet absorber is selected from at least one of triazine or hydroxyphenyl triazine. Further, the triazine ultraviolet absorber is selected from at least one of 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol, 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl)-5-(octoxy)phenol, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, and 2-(2-hydroxy-5-tert-octylphenyl)-1,3,5-triazine.

[0013] Preferably, the hindered phenolic antioxidant is selected from at least one of monophenolic antioxidants, bisphenolic antioxidants, polyphenolic antioxidants, and thiobisphenolic antioxidants.

[0014] The monophenolic antioxidant is selected from at least one of 2,6-di-tert-butyl-4-methylphenol, octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and hexadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; the bisphenolic antioxidant is selected from at least one of 2,2'-methylenebis-(4-methyl-6-tert-butylphenol), 4,4'-thiobis(2-tert-butyl-5-methylphenol), and 2,2'-methylenebis-(4-ethyl-6-tert-butylphenol); the polyphenolic antioxidant is selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris( ... At least one of the following: (-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 3,9-bis[2-(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane; and at least one of the following thiobisphenol antioxidants: 2,2'-thiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(2-tert-butyl-5-methylphenol), and 2,2'-thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0015] Preferably, the mass ratio of the triazine ultraviolet absorber to the hindered phenolic antioxidant is (1-15):1, more preferably (3-8):1.

[0016] Preferably, the yellow pigment in the polycarbonate composition has a weight content of 0.07%-0.7%, more preferably 0.1%-0.5%.

[0017] Furthermore, the polycarbonate composition further comprises 0.05-0.5 parts by weight of a lubricant. The lubricant is selected from at least one of silicone lubricants, ester lubricants, amide lubricants, polyethylene lubricants, stearic acid lubricants, fatty acid and ester lubricants, and montmorillonite lubricants.

[0018] Secondly, the present invention provides a method for preparing the polycarbonate composition, comprising the following steps: mixing the components according to the proportion to obtain a premix, then feeding the obtained premix into a twin-screw extruder for melt mixing, and extruding and granulating to prepare the polycarbonate composition; wherein the length-to-diameter ratio of the twin-screw extruder is 40:1-48:1; the temperature of the twin-screw extruder is set to 230-300℃, and the screw speed is 300-500 rpm.

[0019] Preferably, the temperatures of the twin-screw extruder are set as follows: 230~280℃ for the first section of the barrel, 240~290℃ for the second section, 240~300℃ for the third section, 240~300℃ for the fourth section, 240~300℃ for the fifth section, 240~300℃ for the sixth section, 240~300℃ for the seventh section, 240~300℃ for the eighth section, 240~300℃ for the ninth section, and 240~300℃ for the tenth section.

[0020] Thirdly, the present invention also provides the use of the polycarbonate composition in the preparation of exterior parts for two-wheeled electric vehicles.

[0021] Fourthly, the present invention provides a component comprising the polycarbonate composition described herein. The component is an exterior part for a two-wheeled electric vehicle, an exterior part for an automobile, or a photovoltaic module.

[0022] Furthermore, the exterior components of the two-wheeled electric vehicle specifically include transparent parts such as headlight covers and dashboard covers.

[0023] The present invention has the following beneficial effects: The polycarbonate composition of this invention introduces a siloxane polycarbonate component, which reduces the sensitivity of the matrix resin to UVB light at the molecular level. Simultaneously, a triazine UV absorber and a hindered phenolic antioxidant are added. The triazine UV absorber has strong absorption capacity in the UVB band and can effectively shield ultraviolet rays; the hindered phenolic antioxidant can capture free radicals generated during polycarbonate processing or use, interrupting the photo-oxidation chain reaction. The two work synergistically to effectively inhibit the aging and yellowing of the polycarbonate matrix and the decline in mechanical properties. Furthermore, a specific yellow pigment is introduced, which undergoes controllable and moderate degradation under long-term UVB irradiation, macroscopically "compensating" for the yellowing of the matrix. This effectively reduces the color difference change of the entire material system after long-term UVB aging, exhibiting excellent color stability while ensuring the stability of the material's mechanical properties and light transmittance. Detailed Implementation

[0024] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0025] Where specific experimental steps or conditions are not specified in the examples, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0026] The materials used in the embodiments and comparative examples of this invention are described below, but are not limited to these materials.

[0027] Polycarbonate: Number average molecular weight 23,000, PC2100, Wanhua Chemical; Siloxane polycarbonate: 6% silicon content, PC ST4-3022PJ(3), Samyang, South Korea; Triazine UV absorber 1: 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol, TNUVIN 1600, BASF; Triazine UV absorber 2: 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxy-phenol, TNUVIN 1577, BASF; Benztriazole UV absorbers: 2-(2'-hydroxy-3',5'-bis(α,α-dimethylbenzyl)phenyl)benzotriazole, TNUVIN-234, BASF; Hindered phenolic antioxidant 1: β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester, RIANOX1076, Rianon; Hindered phenolic antioxidant 2: Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], RIANOX1010, Rianon; Phosphite antioxidants: RIANOX 168, Rianon; Yellow pigment 1: Azo Yellow, PV Fast Yellow HGR, Clariant; Yellow pigment 2: Quinoline Yellow, K0961, BASF; Yellow pigment 3: Isoindolinone yellow, K2060SQ, BASF; Yellow pigment 4: Benzidine Yellow, HR02, Clariant; Yellow pigment 5: Bismuth vanadate yellow pigment, Pigment Yellow 184, Shanghai Jingyan Chemical Co., Ltd. Lubricant: Ester-based lubricant, LOXIOL P 861 / 3.5, Corning, Germany.

[0028] Preparation method of polycarbonate compositions in examples and comparative examples: According to the proportions in Table 1 or Table 2, the raw materials are mixed evenly in a high-speed mixer to obtain a premix. The obtained premix is ​​then fed into a twin-screw extruder for melt mixing and extrusion granulation to prepare a polycarbonate composition. The twin-screw extruder has an aspect ratio of 48:1. The twin-screw extruder temperatures are set as follows: first section barrel temperature 240℃, second section barrel temperature 250℃, third section barrel temperature 250℃, fourth section barrel temperature 250℃, fifth section barrel temperature 270℃, sixth section barrel temperature 270℃, seventh section barrel temperature 270℃, eighth section barrel temperature 270℃, ninth section barrel temperature 280℃, and tenth section barrel temperature 280℃. The screw speed is 500 rpm.

[0029] Relevant performance testing methods: 1. Color stability test: A 2mm thick injection-molded color sample was tested using a Datacolor1050 spectrophotometer (D65 light source) to measure the L*, a*, and b* values. The sample was then subjected to 300 hours of UVB irradiation (UVB-313nm, 0.48 W·m). -2 * nm -1 After irradiation at 310 nm and a temperature of 50±3℃, the L*, a*, and b* values ​​of the color plate were tested again. When measuring the color difference of transparent materials, white paper should be placed at the bottom of the color plate to eliminate the influence. The ΔE value was calculated using the color difference calculation formula. The color difference values ​​ΔE after irradiation are shown in Table 1 or Table 2. The smaller the color difference value ΔE, the higher the color stability of the material.

[0030] 2. UV aging resistance test: Irradiation conditions: UVB -313nm, 0.48 W·m -2 * nm -1 310 nm, temperature 50±3℃; irradiation time: 300 hours; (1) The notched impact strength of the specimens before and after irradiation was tested according to ASTM D256-2010 standard. The notched impact test specimens were of American standard thickness and 3.2 mm. The notched impact strength retention rate after irradiation was calculated. (2) The transmittance of the 2mm thick color plate sample before and after irradiation was tested by an optical transmittance meter; the transmittance retention rate after irradiation was calculated.

[0031] Table 1: Distribution ratios (by weight) and performance test results for each group in Examples 1-7

[0032] Table 2: Distribution ratios (by weight) and performance test results for each group in Comparative Examples 1-7

[0033] As can be seen from the above examples and comparative examples, the polycarbonate composition of the present invention, by introducing a siloxane polycarbonate component and adding a specific proportion of triazine UV absorber and hindered phenolic antioxidant, as well as a specific yellow pigment, exhibits excellent color stability, mechanical property stability and transmittance stability. After UVB irradiation test, the color difference value ΔE ≤ 4.5, the notched impact strength retention rate ≥ 85%, and the transmittance retention rate ≥ 83%.

[0034] Comparing Comparative Examples 1 and 3 with Example 1, it can be seen that after UVB irradiation tests, the color difference value increases and the notched impact strength retention rate and light transmittance retention rate decrease when using phosphite antioxidants or without adding antioxidants.

[0035] Comparing Comparative Examples 4, 5, and 6 with Example 1, it can be seen that after UVB irradiation tests, the color difference value increases, the color stability of the material is poor, and the retention rates of notched impact strength and light transmittance also decrease when using benzidine yellow powder or bismuth vanadate yellow pigment powder or without adding yellow pigment powder.

[0036] The above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A polycarbonate composition, characterized in that, By weight, it includes the following components: 50-80 parts polycarbonate; 20-50 parts of siloxane polycarbonate; 0.3-2 parts of triazine ultraviolet absorber; 0.1-0.8 parts of hindered phenolic antioxidants; 0.1-0.5 parts of yellow pigment; The yellow pigment is selected from at least one of azo yellow, quinoline yellow, or isoindolinone yellow.

2. The polycarbonate composition according to claim 1, characterized in that, The polycarbonate has a number average molecular weight of 18,000-32,000.

3. The polycarbonate composition according to claim 1, characterized in that, The silicon content of the siloxane polycarbonate is 6%-10%.

4. The polycarbonate composition according to claim 1, characterized in that, The triazine ultraviolet absorber is selected from at least one of triazine or hydroxyphenyl triazine.

5. The polycarbonate composition according to claim 1, characterized in that, The hindered phenolic antioxidant is selected from at least one of monophenolic antioxidants, bisphenolic antioxidants, polyphenolic antioxidants, and thiobisphenolic antioxidants.

6. The polycarbonate composition according to claim 1, characterized in that, The mass ratio of the triazine ultraviolet absorber to the hindered phenolic antioxidant is (1-15):1, preferably (3-8):

1.

7. The polycarbonate composition according to claim 1, characterized in that, The yellow pigment in the polycarbonate composition has a weight content of 0.07%-0.7%, preferably 0.1%-0.5%.

8. The polycarbonate composition according to claim 1, characterized in that, It also includes 0.05-0.5 parts by weight of lubricant.

9. A method for preparing a polycarbonate composition according to any one of claims 1-8, characterized in that, Includes the following steps: The components are stirred and mixed according to the formula to obtain a premix. The obtained premix is ​​then fed into a twin-screw extruder for melt mixing and extrusion granulation to prepare a polycarbonate composition. The length-to-diameter ratio of the twin-screw extruder is 40:1-48:

1. The temperature of the twin-screw extruder is set to 230-300℃ and the screw speed is 300-500rpm.

10. A component, characterized in that, The polycarbonate composition includes any one of claims 1-8; the part is an exterior component for a two-wheeled electric vehicle, an exterior component for an automobile, or a photovoltaic module.

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