A polycarbonate composition and its preparation method and application

Abstract

The present invention discloses a polycarbonate composition. The polycarbonate composition comprises the following components, by weight: 39-61 parts of PC resin, 9-31 parts of PET resin, 5-15 parts of modified glass fiber, 10-30 parts of modified talc, 1-3.5 parts of modified mica flakes, 1-5 parts of modified wollastonite, and 0-5 parts of an additive. The mass ratio of the modified glass fiber, modified talc, modified mica flakes, and modified wollastonite is (1-5):10:(0.8-1.3):(0.5-3.5). The mass ratio of the modified mica flakes to the modified glass fiber, modified talc, and modified wollastonite is ≤1:14. The pH range of the modified glass fiber, modified talc, modified mica flakes, and modified wollastonite is 7-8. The polycarbonate composition not only has good heat resistance and dimensional stability, but also has an excellent appearance.

Description

Technical Field

[0001] The present invention belongs to the technical field of polycarbonate, and more specifically, relates to a polycarbonate composition, a preparation method and an application thereof. Background Art

[0002] With the booming new energy vehicle industry, new technologies such as assisted driving have also seen significant development. LiDAR, as an advanced detection technology, is increasingly being used in new energy vehicles. Most OEMs prefer roof-mounted LiDAR. Considering factors such as assembly, cost, and aesthetics, plastic is often used for the exterior shell of radar assemblies. Common automotive exterior materials include PP, PC / ABS, and PC / PBT alloys. Because automotive exterior materials such as LiDAR are mounted on the roof and exposed to constant sunlight, and because radar operation also generates heat, materials suitable for radar covers must possess high heat resistance. PP, however, has relatively low heat resistance, limiting its use. PC / ABS or PC / PBT solutions offer advantages such as high heat resistance and excellent paintability, resulting in high gloss finishes for exterior parts and enhancing the overall vehicle aesthetic. However, both PC / ABS and PC / PBT alloys experience significant dimensional fluctuations due to thermal expansion and contraction. These unstable dimensions can lead to loose fitting, hindering production, or create gaps in the vehicle body that impact the consumer's perception of the vehicle.

[0003] Patent CN 104693789A discloses a PA6 reinforced material filled with phlogopite and glass fiber composites. This material utilizes phlogopite and glass fiber composites in a resin matrix to fill PA6. Phlogopite powder is added to the glass fiber-reinforced PA6, addressing shortcomings of simple glass fiber-reinforced PA6, such as uneven shrinkage, poor dimensional stability, warping, poor weather resistance, and poor gloss. While the addition of phlogopite and glass fiber improves the mechanical properties and dimensional stability of the composite material to a certain extent, both mica and glass fiber are high-aspect-ratio minerals, which are prone to orientation in the plastic melt. This results in material flow properties being much stronger than those perpendicular to the flow direction, which is extremely detrimental to the production of large, stable parts. Furthermore, high-aspect-ratio minerals are difficult to evenly disperse in the resin matrix during the injection molding process, and are prone to appearing on the surface of the final product, resulting in appearance defects that affect the aesthetics. Consequently, the appearance and stability issues commonly encountered in practical applications of glass fiber-reinforced materials containing different fillers have remained unresolved. Summary of the Invention

[0004] In view of the above-mentioned existing technical problems, the primary object of the present invention is to provide a polycarbonate composition, which not only has good heat resistance and dimensional stability, but also has excellent appearance.

[0005] The second object of the present invention is to provide a method for preparing a polycarbonate composition.

[0006] The third object of the present invention is to provide an application of a polycarbonate composition in the field of automotive materials.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] A polycarbonate composition comprises the following components, measured in parts by weight: 39-61 parts of PC resin, 9-31 parts of PET resin, 5-15 parts of modified glass fiber, 10-30 parts of modified talc powder, 1-3.5 parts of modified mica flakes, 1-5 parts of modified wollastonite, and 0-5 parts of an additive; the mass ratio of the modified glass fiber, modified talc powder, modified mica flakes, and modified wollastonite is (1-5):10:(0.8-1.5):(0.5-3.5); the mass ratio of the modified mica flakes to the modified glass fiber, modified talc powder, and modified wollastonite is ≤1:14; and the pH range of the modified glass fiber, modified talc powder, modified mica flakes, and modified wollastonite is 7-8.

[0009] The present invention utilizes modified glass fiber, modified talc, modified mica flakes, and modified wollastonite in a specific ratio. Within this ratio, the heat resistance, dimensional stability, and appearance of the polycarbonate composition are significantly improved. Outside this ratio, the appearance, heat resistance, and dimensional stability of the polycarbonate composition are not balanced.

[0010] The inventors further discovered that among various mineral powders, mica flakes generally have the largest aspect ratio. This can easily lead to orientation during the PC / PET molding process, affecting the overall material performance. Furthermore, an excessively large aspect ratio can cause the mineral powder to float on the surface of the part, creating a rough feel and affecting the appearance. However, when the mass ratio of modified mica flakes to modified glass fiber, modified talc, and modified wollastonite is ≤ 1:14, the modified mica flakes, combined with the other mineral powders, can be more evenly dispersed in the resin matrix. The mica that originally floated on the surface can be better encapsulated by the resin, thereby leveraging its high rigidity. This, in turn, not only meets the high heat resistance and high rigidity requirements of the polycarbonate composition, but also further enhances the composition's appearance and sprayability.

[0011] In addition, the present invention also pre-treats the mineral powder through a mineral powder pre-treatment method, thereby reducing the pH value of the mineral powder, avoiding the catalytic degradation of the ester bond structure in PC and PET by the alkaline mineral powder, improving the thermal stability of the polycarbonate composition, and avoiding the generation of material flowers, silver wires and other undesirable appearance problems during the injection molding process.

[0012] The present invention controls the compounding ratio of the modified mineral powder, controls the mass ratio of the modified mica flakes to other modified mineral powders in the modified mineral powder, optimizes the pH value of the mineral powder, and combines other components in the composition system to ensure that the composition has excellent heat resistance and dimensional stability while also having an excellent appearance.

[0013] Preferably, the aspect ratio of the modified glass fiber is (10-30):1; more preferably, the aspect ratio of the modified glass fiber is (18-20):1.

[0014] Preferably, the aspect ratio of the modified talc powder is (8-15):1; more preferably, the aspect ratio of the modified talc powder is (9-12):1.

[0015] Preferably, the aspect ratio of the modified mica sheet is (25-40):1; more preferably, the aspect ratio of the modified mica sheet is (28-32):1.

[0016] Preferably, the aspect ratio of the modified wollastonite is (10-15):1; more preferably, the aspect ratio of the modified wollastonite is (12-13):1.

[0017] In the present invention, the aspect ratio of modified glass fiber, modified talc, modified mica flakes and modified wollastonite is measured by randomly selecting 100 modified mineral powders for measurement using a two-dimensional microscope, and finally calculating their aspect ratios to obtain an average value.

[0018] Preferably, the PC resin has a melt index of 15 to 25 g / 10 min at 300° C. and 1.2 kg; more preferably, the PC resin has a melt index of 19 to 20 g / 10 min at 300° C. and 1.2 kg. The PC resin is tested in accordance with ISO-1133-2011.

[0019] Specifically, in the polycarbonate composition, the content of the PC resin is not less than 38.6%.

[0020] Preferably, the PET resin has a melt index of 35 to 45 g / 10 min at 250° C. and 5 kg; more preferably, the PET resin has a melt index of 38 to 42 g / 10 min at 250° C. and 5 kg. The PET resin is tested in accordance with ISO-1133-2011.

[0021] Preferably, the auxiliary agent is a lubricant.

[0022] Furthermore, the present invention claims protection for a method for preparing a polycarbonate composition, comprising the following steps:

[0023] (1) Pretreatment: mixing the mineral powder with an acetic acid aqueous solution, stirring, filtering, collecting the solid matter, and drying to obtain a modified mineral powder; the modified mineral powder includes modified glass fiber, modified talc, modified mica flakes, and modified wollastonite;

[0024] (2) PC resin, PET resin, modified glass fiber, modified talc powder, modified mica flakes, modified wollastonite and additives are mixed and melt-extruded to obtain a polycarbonate composition.

[0025] The present invention pre-treats the mineral powder in the polycarbonate composition, thereby effectively reducing impurities in the raw mineral powder, significantly reducing the pH value of the modified mineral powder, avoiding the catalytic degradation of the ester bond structure in PC and PET resins by the alkaline mineral powder, and ensuring the stability of the material performance.

[0026] Preferably, in step (1), the mass volume ratio of the mineral powder to the acetic acid aqueous solution is (2-1): 1 kg / L.

[0027] Preferably, in the acetic acid aqueous solution, the volume ratio of acetic acid to water is (18-22):1.

[0028] Preferably, in step (1), the drying temperature is 90-100°C.

[0029] Preferably, in step (1), the mixing speed is 1000-2000 rpm.

[0030] Preferably, in step (2), a twin-screw extruder is used for melt extrusion, and the aspect ratio of the twin-screw extruder is 42 to 48:1.

[0031] Preferably, in step (2), the screw speed of the twin-screw extruder is 450 to 650 rpm.

[0032] Preferably, in step (2), the temperature of the melt extrusion is 255-265°C.

[0033] Furthermore, the present invention also seeks to protect the application of the polycarbonate composition in the field of automotive materials. Specifically, the polycarbonate composition can be used as an automotive exterior material such as a lidar cover, especially in applications with high requirements for heat resistance, size, and appearance.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] By controlling the compounding ratio of the modified mineral powder, controlling the mass ratio of the modified mica flakes to other modified mineral powders in the modified mineral powder, optimizing the pH value of the mineral powder, and combining the other components of the composition system, the present invention ensures that the polycarbonate composition not only has excellent heat resistance and dimensional stability, but also has an excellent appearance. After heat stability testing and spray testing, the polycarbonate composition did not experience cracking, blistering, or discoloration, and the overall sample was free of deformation. Furthermore, the polycarbonate composition has an excellent appearance, with no silver streaks, material flakes, or air marks observed on the product surface. DETAILED DESCRIPTION

[0036] The present invention is further described below with reference to the specification and specific examples, which are not intended to limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0037] The raw materials of the embodiments and comparative examples are as follows:

[0038] PC resin 1, melt index at 300°C, 1.2 kg, is 20 g / 10 min, brand CH8225, produced by Cangzhou Dahua.

[0039] PC resin 2, melt index at 300°C, 1.2 kg, is 22 g / 10 min, brand PC 2220, manufactured by Wanhua Chemical.

[0040] PC resin 3, with a melt index of 19 g / 10 min at 300°C and 1.2 kg, is POLYCARBONATERESIN TARFLON FN1900, with a glossy finish.

[0041] PET resin 1, with a melt index of 40 g / 10 min at 250° C. and 5 kg, brand PET BG80, produced by Yizheng Chemical Fiber.

[0042] PET resin 2, with a melt index of 45 g / 10 min at 250°C and 5 kg, brand PET FG604, produced by Yizheng Chemical Fiber.

[0043] PET resin 3, melt index of 35 g / 10 min at 250°C and 5 kg, brand PET CR7702, produced by China Resources Chemical.

[0044] Glass fiber 1, aspect ratio 20:1, pH 8-9, brand HMG436S-10-4.0, Taishan Fiberglass.

[0045] Glass fiber 2, aspect ratio of 23:1, pH 8-9, brand ECS13-4.5-534A, Jushi Glass Fiber.

[0046] Glass fiber 3, aspect ratio of 16:1, pH 8-9, brand glass fiber ECS13-3.0-T436W, Jushi Glass Fiber.

[0047] Talc 1, aspect ratio 10:1, pH 9-10, brand TYT-777A, Haicheng Tianyuan.

[0048] Talc 2, aspect ratio of 15:1, pH 9-10, brand HTP Ultra 5L, Aihai Yimi.

[0049] Talc 3, aspect ratio 8:1, pH 9-10, brand SDC-9489, Xinda.

[0050] Mica flake 1, aspect ratio 30:1, pH 9-10, brand 300HC, Huajing Mica.

[0051] Mica flake 2, aspect ratio 25:1, pH 9-10, brand YM-SW500, Suzhou Zhongwei.

[0052] Mica flakes 3, aspect ratio 40:1, pH 9-10, brand mica powder-P-325 mesh, Jingda Mica.

[0053] Wollastonite 1, aspect ratio 11:1, pH 9-10, brand WFC5, Fengjiashan silica fiber.

[0054] Wollastonite 2, aspect ratio of 12:1, pH 9-10, brand NYAD 400, NYCO.

[0055] Wollastonite 3, aspect ratio 10:1, pH 9-10, brand XYNFW-SW 6.5, southern wollastonite.

[0056] The above-mentioned mineral powder is processed by the following pretreatment method to obtain modified mineral powder:

[0057] The above-mentioned mineral powders (glass fiber, talc, mica flakes, or wollastonite) were mixed with an acetic acid aqueous solution (acetic acid to water volume ratio of 20:1) at a ratio of 1 L of solution to 1 kg of mineral powder at room temperature, stirred thoroughly, and mixed evenly for 6 hours. The solid matter was filtered and collected, and then dried in a 100°C oven for 12 hours to obtain modified mineral powders (corresponding to modified glass fiber, modified talc, modified mica flakes, or modified wollastonite, respectively). The following modified glass fiber 1 was prepared by modifying glass fiber 1, modified talc 1 was prepared by modifying talc 1, modified mica flake 1 was prepared by modifying mica flake 1, and so on.

[0058] Modified glass fiber 1, pH value 7 to 7.5.

[0059] Modified glass fiber 2, pH value 7 to 7.5.

[0060] Modified glass fiber 3, pH value 7 to 7.5.

[0061] Modified talc 1, pH value 7.5~8.

[0062] Modified talc 2, pH value 7.5~8.

[0063] Modified talc 3, pH value 7.5~8.

[0064] Modified mica flake 1, pH value 7.5-8.

[0065] Modified mica flakes 2, pH value 7.5-8.

[0066] Modified mica flakes 3, pH value 7.5-8.

[0067] Modified wollastonite 1, pH value 7.5-8.

[0068] Modified wollastonite 2, pH value 7.5-8.

[0069] Modified wollastonite 3, pH value 7.5~8.

[0070] Additive, lubricant, pentaerythritol stearate, commercially available.

[0071] Acetic acid, commercially available.

[0072] Unless otherwise specified, the components (such as lubricants) used in the parallel examples and comparative examples are all the same commercially available products.

[0073] Example 1

[0074] The weight parts of the raw materials used in Example 1 are shown in Table 1.

[0075] A method for preparing a polycarbonate composition, comprising the following steps:

[0076] (1) According to the raw material ratio in Table 1, PC resin, PET resin, modified glass fiber, modified talc powder, modified mica flakes, modified wollastonite and additives were put into a high-speed mixer and mixed uniformly at a speed of 1000 to 2000 rpm. The final mixture was put into a twin-screw extruder (length-to-diameter ratio 45:1, speed 550 rpm), extruded and granulated at 260° C. to obtain a polycarbonate composition.

[0077] Examples 2 to 17

[0078] The weight parts of the raw materials used in the following examples are shown in Table 1.

[0079] The specific preparation steps of the following examples are the same as those of Example 1.

[0080] Comparative Examples 1 to 11

[0081] The weight parts of the raw materials used in the following comparative examples are shown in Table 2.

[0082] The specific preparation steps of each comparative example are the same as those of Example 1.

[0083] Table 1

[0084]

[0085]

[0086]

[0087] Table 2 shows the formula components of each comparative example:

[0088] Table 2

[0089]

[0090] The polycarbonate compositions prepared in the above examples and comparative examples were tested according to the following test methods.

[0091] Heat resistance test:

[0092] (1) Heat Deformation Temperature Test: In accordance with ISO 75-2-2003, standard specimens obtained by injection molding the polycarbonate compositions prepared in the Examples and Comparative Examples were tested under a load of 1.8 MPa.

[0093] (2) Thermal shock test: The polycarbonate compositions prepared in the examples and comparative examples were injection molded into large-size samples of 365*100*3 mm. The samples were placed in a 120°C oven and observed for 48 hours to see whether cracking, blistering, or discoloration occurred on the sample surface, and whether the sample as a whole was deformed. If there was no cracking, blistering, or discoloration on the sample surface, and no overall deformation, the product was rated as Level 1; if there was no cracking, blistering, or discoloration, but slight deformation, the product was rated as Level 2; if there was cracking, blistering, or discoloration, and the product was deformed, the product was rated as Level 3.

[0094] Appearance Test: The polycarbonate compositions prepared in the Examples and Comparative Examples were injection molded into products measuring approximately 505 x 170 x 40 mm (with a wall thickness of approximately 2.5 mm). The surfaces of the products were inspected for any silver streaks, material smears, or air marks. If no silver streaks, material smears, or air marks were observed, the product was rated as Grade 1; if slight air marks were present, the product was rated as Grade 2; if silver streaks or material smears were present, the product was rated as Grade 3.

[0095] Spraying Test: The polycarbonate compositions prepared in the Examples and Comparative Examples were injection molded into parts and spray-painted. After painting, the parts were then subjected to a 120°C heat storage test. After 48 hours, the parts were observed for surface cracking, blistering, discoloration, and overall deformation. If the parts exhibited no surface cracking, blistering, discoloration, or overall deformation, they were rated Grade 1. If there was no cracking, blistering, or discoloration, but slight deformation, they were rated Grade 2. If there was both cracking, blistering, and discoloration, as well as deformation, they were rated Grade 3.

[0096] Table 3 and Table 4 are the performance test results of each embodiment and comparative example respectively.

[0097] Table 3

[0098]

[0099] Table 4

[0100]

[0101] As shown in Examples 1-17 above, the polycarbonate compositions prepared according to the present invention exhibit excellent heat resistance and dimensional stability. After heat stability testing and spray coating testing, the polycarbonate compositions exhibited heat deformation temperatures of ≥109°C, without any cracking, blistering, or discoloration, and the overall sample exhibited no deformation. Furthermore, the polycarbonate compositions exhibited excellent appearance, with no silver streaks, material flakes, or air marks observed on the product surface.

[0102] As shown in Example 1, Comparative Examples 1, and 2, when the ratio of modified mineral powders (modified glass fiber, modified talc, modified mica flakes, and modified wollastonite) in the polycarbonate system is outside the scope of protection of the present invention, the resulting polycarbonate composition exhibits slight deformation after thermal shock testing; silver streaks, material flakes, or air marks appear on the surface of the injection-molded product; and cracking, blistering, discoloration, or overall deformation occurs after spray testing. The polycarbonate composition prepared in Example 1 also exhibits a higher heat deformation temperature than the polycarbonate compositions in Comparative Examples 1 and 2.

[0103] Comparative Example 3 shows that when the mass ratio of modified mica flakes to modified glass fiber, modified talc, and modified wollastonite in the polycarbonate system is outside the scope of the present invention, the resulting polycarbonate composition exhibits silver streaks, material flakes, or gas marks; and after spray testing, cracking, blistering, discoloration, or overall deformation. The heat deformation temperature of the polycarbonate composition prepared in Example 1 is also higher than that of the polycarbonate composition in Comparative Example 3.

[0104] It can be seen from Example 1 and Comparative Examples 4 to 7 that when the polycarbonate system lacks one of the modified mineral powders of the present invention (modified glass fiber, modified talc, modified mica flakes, and modified wollastonite), the heat deformation temperature of the polycarbonate composition prepared in Example 1 is significantly higher than that of the polycarbonate compositions in Comparative Examples 4 to 7. In addition, the polycarbonate composition cannot meet the requirements of appearance and spraying tests, and will show slight deformation after thermal shock testing.

[0105] As shown in Example 1 and Comparative Examples 8-11, when any unmodified mineral powder is used in the polycarbonate system, the polycarbonate compositions prepared in Comparative Examples 9 and 11 exhibit slight deformation after thermal shock testing, while the polycarbonate compositions prepared in Comparative Examples 8 and 10 exhibit cracking, blistering, discoloration, and product deformation. Furthermore, the polycarbonate compositions in Comparative Examples 8, 10, and 11 exhibit silver streaks and material flakes. Furthermore, the polycarbonate compositions in Comparative Examples 9-11 exhibit cracking, blistering, discoloration, and deformation after spray testing.

[0106] The foregoing examples are merely illustrative, serving to illustrate some of the features of the method of the present invention. The appended claims are intended to claim the widest possible scope that can be envisioned, and the embodiments presented herein are demonstrated by the applicant's actual experimental results. Therefore, the applicant intends that the appended claims are not limited by the selection of examples illustrating the features of the present invention. Some numerical ranges used in the claims also include subranges therein, and variations in these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A polycarbonate composition, characterized in that The composition comprises the following components by weight: 39-61 parts of PC resin, 9-31 parts of PET resin, 5-15 parts of modified glass fiber, 10-30 parts of modified talc powder, 1-3.5 parts of modified mica flakes, 1-5 parts of modified wollastonite, and 0-5 parts of additives. The mass ratio of the modified glass fiber, modified talc powder, modified mica flakes and modified wollastonite is (1-5):10:(0.8-1.3):(0.5-3.5); The mass ratio of the modified mica flakes to the modified glass fiber, modified talc powder and modified wollastonite is ≤1:14; The pH range of the modified glass fiber, modified talc, modified mica flakes and modified wollastonite is 7 to 8; The glass fiber, talc powder, mica flake or wollastonite are respectively mixed with an acetic acid aqueous solution, stirred, filtered, solid matter is collected, and dried to obtain modified glass fiber, modified talc powder, modified mica flake and modified wollastonite.

2. The polycarbonate composition according to claim 1, wherein The aspect ratio of the modified glass fiber is (10-30):

1.

3. The polycarbonate composition according to claim 1, wherein The aspect ratio of the modified talc powder is (8-15):

1.

4. The polycarbonate composition according to claim 1, wherein The aspect ratio of the modified mica sheet is (25-40):

1.

5. The polycarbonate composition according to claim 1, wherein The aspect ratio of the modified wollastonite is (10-15):

1.

6. The polycarbonate composition according to claim 1, wherein The PC resin has a melt index of 15 to 25 g / 10 min at 300° C. and 1.2 kg.

7. The polycarbonate composition according to claim 1, wherein The PET resin has a melt index of 35 to 45 g / 10 min at 250° C. and 5 kg.

8. The method for preparing the polycarbonate composition according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Pretreatment: The mineral powder is mixed with an acetic acid aqueous solution, stirred, filtered, the solid matter is collected, and dried to obtain a modified mineral powder; The modified mineral powder includes modified glass fiber, modified talc, modified mica flakes and modified wollastonite; (2) PC resin, PET resin, modified glass fiber, modified talc powder, modified mica flakes, modified wollastonite and additives are mixed and melt-extruded to obtain a polycarbonate composition.

9. The method for preparing the polycarbonate composition according to claim 8, wherein: The mass volume ratio of the mineral powder to the acetic acid aqueous solution is (2-1): 1 kg / L.

10. Use of the polycarbonate composition according to any one of claims 1 to 7 in the field of automotive materials.

Images