Preparation method of automobile rearview mirror shell based on thermoplastic carbon fiber composite material
By using vacuum forming and molding technology, and combining polycarbonate and carbon fiber layers, the molding problem of thermoplastic carbon fiber composite materials on complex large curved automotive rearview mirror housings has been solved, achieving efficient and low-cost mass production and material recycling.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-17
- Publication Date
- 2026-03-10
AI Technical Summary
In existing technologies, thermoplastic carbon fiber composite materials are prone to fiber twisting, wrinkling, layup instability, and poor interfacial bonding during the molding process of complex large curved automotive rearview mirror shells with small minimum curvature radii, making it difficult to achieve efficient and low-cost mass production.
A polycarbonate layer is prepared using vacuum forming as a preform carrier. Combined with carbon fiber dry cloth and molding technology, the carbon fiber flexibility is maintained at room temperature through the design of the shaping layer, and in-situ pre-impregnation is achieved during the molding process to form a stable thermoplastic carbon fiber composite material.
Achieving stable molding of fiber-free, wrinkle-free appearance on large curved surfaces with a small minimum radius of curvature significantly shortens the molding cycle, reduces costs, and enables material recyclability, thus solving the application problem of thermoplastic carbon fiber composite materials in complex large curved automotive exterior parts.
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Figure CN121625482A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of automobile trim, in particular to a preparation method of an automobile rearview mirror shell based on thermoplastic carbon fiber composite material. BACKGROUND
[0002] With the continuous improvement of light weight and appearance quality requirements of new energy vehicles, carbon fiber composite materials are gradually applied to automobile rearview mirror shells and other exterior trim parts. In the prior art, the automobile rearview mirror shell is mostly made of thermosetting epoxy resin carbon fiber prepreg, which is formed by autoclave or molding process. Such materials have good operability at room temperature and can adapt to certain degree of curved surface forming requirements.
[0003] However, these forming methods in the prior art generally have the problems of long preparation period, low production efficiency, high cost and difficult recycling, which are not conducive to mass industrial production. In order to meet the demand of cost reduction and efficiency increase and carbon emission reduction, thermoplastic carbon fiber composite material is tried to replace thermosetting material, but the thermoplastic carbon fiber composite material has large rigidity at room temperature and poor conformability, especially in the forming process of complex large curved surface rearview mirror shell with small minimum curvature radius, which is prone to defects such as fiber twisting, wrinkling, ply instability and poor interface bonding. SUMMARY
[0004] An object of the present application is to provide a preparation method of an automobile rearview mirror shell based on thermoplastic carbon fiber composite material, which solves the technical problem that the prior art cannot realize efficient, low-cost and batch forming of thermoplastic carbon fiber composite material on complex large curved surface automobile rearview mirror shell with small minimum curvature radius while ensuring appearance quality and structural stability.
[0005] Another object of the present application is to further improve the forming stability of the rearview mirror shell.
[0006] According to the object of the present application, the present application provides a preparation method of an automobile rearview mirror shell based on thermoplastic carbon fiber composite material, comprising: a first polycarbonate layer and a second polycarbonate layer with a predetermined thickness are prepared by using a vacuum forming process; the first polycarbonate layer is clamped on the surface of a first metal mold core, and a shaping layer is prepared on the surface of the polycarbonate layer, the thickness of the shaping layer being any value in the range of 0.05mm-0.10mm; a carbon fiber layer with a predetermined size is laid on the surface of the shaping layer; the second polycarbonate layer is placed on the surface of the carbon fiber layer to prepare a laminated rearview mirror shell, and a second metal mold core is clamped on the surface of the second polycarbonate layer; the rearview mirror shell is subjected to a molding forming treatment to prepare the automobile rearview mirror shell; wherein, The preset thickness is any value between 0.1mm and 0.2mm, and the minimum radius of curvature of the rearview mirror housing is less than or equal to 50mm.
[0007] Optionally, the shaping layer contains 70-80 parts polyurethane, 5-10 parts ethyl acetate, and 10-15 parts epoxy resin.
[0008] Optionally, the molding process includes preheating, heat preservation, pressure holding, cooling and demolding processes performed sequentially.
[0009] Optionally, the pressure holding pressure of the pressure holding process is any value between 2MPa and 5MPa.
[0010] Optionally, the pressure holding temperature of the pressure holding process is any value between 240℃ and 260℃.
[0011] Optionally, the pressure holding time of the pressure holding process is any value between 300s and 600s.
[0012] Optionally, a release agent is coated on the side of the first metal mold core facing the first polycarbonate layer, and the release agent is coated on the side of the second metal mold core facing the second polycarbonate layer.
[0013] Optionally, the temperature of the demolding process is any value between 70℃ and 90℃.
[0014] This invention constructs a molding path for thermoplastic carbon fiber composite materials, using a vacuum-formed polycarbonate layer as a preform carrier, dry carbon fiber fabric as a reinforcing phase, and in-situ prepreg via molding. This allows the carbon fiber to be in a highly flexible and easily conformable state before prepreg, achieving fiber-free, wrinkle-free, and aesthetically stable automotive rearview mirror housings that can be mass-produced even in large curved surfaces with a minimum radius of curvature R less than or equal to 50 mm. Compared to existing thermosetting epoxy prepreg molding methods, this embodiment significantly shortens the molding cycle, reduces manufacturing costs, and enables material recyclability while ensuring appearance and mechanical properties. It solves the technical challenge of applying thermoplastic carbon fiber composite materials to complex, large-curvature automotive exterior parts.
[0015] Furthermore, the molding process of the present invention includes preheating, heat preservation, pressure holding, cooling and demolding processes performed sequentially, so that the heating and pressure processes of the rearview mirror housing at each stage of the molding process are controllable, continuous and stable.
[0016] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description
[0017] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic flowchart of a method for manufacturing a rearview mirror housing according to an embodiment of the present invention; Figure 2 This is a schematic partial structural diagram of a rearview mirror housing according to an embodiment of the present invention.
[0018] Figure label: 100 - Rearview mirror housing, 10 - First polycarbonate layer, 20 - Second polycarbonate layer, 30 - First metal core, 40 - Shaping layer, 50 - Carbon fiber layer, 60 - Second metal core. Detailed Implementation
[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.
[0020] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.
[0021] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.
[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0023] Figure 1 This is a schematic flowchart of a method for manufacturing a rearview mirror housing according to an embodiment of the present invention. Figure 2 This is a schematic partial structural diagram of a rearview mirror housing according to an embodiment of the present invention.
[0024] like Figure 1 As shown, the present invention provides a method for preparing a car rearview mirror housing 100 based on thermoplastic carbon fiber composite material, comprising the following steps: Step S100: Prepare a first polycarbonate layer 10 and a second polycarbonate layer 20 with a preset thickness using a vacuum forming process; Step S200: The first polycarbonate layer 10 is attached to the surface of the first metal mold core 30, and a shaping layer 40 is prepared on the surface of the polycarbonate layer. The thickness of the shaping layer 40 is any value between 0.05mm and 0.10mm. Step S300: Lay a carbon fiber layer 50 of a preset size on the surface of the shaping layer 40; Step S400: Place the second polycarbonate layer 20 on the surface of the carbon fiber layer 50 to prepare a rearview mirror housing 100 with a stacked arrangement, and snap the second metal mold core 60 onto the surface of the second polycarbonate layer. Step S500: The rearview mirror housing 100 is subjected to compression molding to obtain the automotive rearview mirror housing 100, wherein the preset thickness is any value between 0.1mm and 0.2mm, and the minimum radius of curvature R of the rearview mirror housing 100 is less than or equal to 50mm.
[0025] In this embodiment, the method for preparing the automotive rearview mirror housing 100 involves first preparing a first metal mold core 30, then attaching a first polycarbonate layer 10 prepared using a vacuum forming process to the surface of the first metal mold core 30, then coating the surface of the first polycarbonate with a shaping layer 40 of any thickness between 0.05mm and 0.10mm, then laying a carbon fiber layer 50 cut to a preset size on the surface of the shaping layer 40, placing a second polycarbonate layer 20 on the surface of the carbon fiber layer 50, thus obtaining a rearview mirror housing 100 with a stacked arrangement, then attaching a second metal mold core 60 to the surface of the second polycarbonate, and finally performing a compression molding process on the rearview mirror housing 100 to obtain the automotive rearview mirror housing 100. Here, the thickness of the shaping layer 40 can be 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm or 0.1mm, or any other value between 0.05mm and 0.1mm. The thickness of the first polycarbonate layer 10 and the second polycarbonate layer 20 can be 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm or 0.2mm, or any other value between 0.1mm and 0.2mm. The minimum radius of curvature R of the rearview mirror housing 100 obtained can be 50mm, 40mm, 30mm or 20mm.
[0026] In this embodiment, a thermoplastic carbon fiber composite material molding path is constructed, using a vacuum-formed polycarbonate layer as a preform carrier, carbon fiber dry cloth as a reinforcing phase, and in-situ prepreg via molding. This allows the carbon fiber to be in a highly flexible and easily conformable state before prepreg, achieving fiber-free, wrinkle-free, and aesthetically stable automotive rearview mirror housing 100 that can be mass-produced even in large curved surface areas with a minimum radius of curvature R less than or equal to 50 mm. Compared to existing thermosetting epoxy prepreg molding methods, this embodiment significantly shortens the molding cycle, reduces manufacturing costs, and enables material recyclability while ensuring appearance and mechanical properties. It solves the technical challenge of applying thermoplastic carbon fiber composite materials to complex large curved automotive exterior parts.
[0027] In step S100, a first polycarbonate layer 10 and a second polycarbonate layer 20 with a preset thickness are prepared using a vacuum forming process. The vacuum forming process allows the first polycarbonate layer 10 and the second polycarbonate layer 20 to obtain a three-dimensional large curved surface shape consistent with the rearview mirror housing 100 in the early stage of molding, avoiding the instability of the layup due to excessive overall deformation during the subsequent molding process. Furthermore, by setting the thickness of the first polycarbonate layer 10 and the second polycarbonate layer 20 in the range of 0.1mm-0.2mm, the first polycarbonate layer 10 and the second polycarbonate layer 20 have sufficient molding rigidity and can fully melt and penetrate into the carbon fiber layer 50 during the molding stage, providing a resin source for subsequent prepreg. In other words, it provides a stable, low-cost, and easily formable large curved surface bearing interface for the subsequent laying of the carbon fiber layer 50 and molding prepreg.
[0028] In step S200, the first polycarbonate layer 10 is clamped onto the surface of the first metal mold core 30, and a shaping layer 40 with a thickness of 0.05mm-0.10mm is prepared on its surface. The first metal mold core 30 provides precise curved surface support for the vacuum forming of the first polycarbonate layer 10, ensuring the geometric accuracy of the large curved surface. The shaping layer 40 is used to temporarily fix the carbon fiber dry cloth to the surface of the first polycarbonate layer 10 under normal temperature or low temperature conditions, preventing slippage or warping during subsequent laying and molding processes. The thickness of the shaping layer 40 is controlled so that it can provide sufficient adhesion without forming a barrier layer during the high-temperature molding stage, thereby affecting the full wetting of the carbon fiber by the polycarbonate.
[0029] In step S300, by laying a carbon fiber layer 50 of a preset size on the surface of the shaping layer 40, it is kept in a soft state during the laying stage, which significantly improves its conformability to surfaces with double curvature and large curvature. In conjunction with the shaping layer 40, the carbon fiber layer 50 can still maintain uniform adhesion in areas with small curvature radii.
[0030] In step S400, the second polycarbonate layer 20 is placed on the surface of the carbon fiber layer 50 to form a stacked rearview mirror housing 100. The second metal mold core 60 is then attached to the surface of the second polycarbonate layer 20, so that the second polycarbonate layer 20 and the first polycarbonate layer 10 together form a sandwich structure, providing a bidirectional resin source for the carbon fiber layer 50. Furthermore, the symmetrical arrangement is beneficial for forming uniform pressure and heat conduction conditions during the molding process, avoiding local dry spots or warping caused by insufficient penetration on one side. The second metal mold core 60 further limits the shape accuracy of the rearview mirror housing 100, ensuring the consistency and repeatability of the large curved surface, so that the entire structure has a stable, symmetrical, and controllable prepreg configuration before entering the molding stage.
[0031] In a further embodiment, the shaping layer 40 contains 70-80 parts of polyurethane, 5-10 parts of ethyl acetate, and 10-15 parts of epoxy resin. That is, the polyurethane in the shaping layer 40 can be 70, 72, 74, 76, 78, or 80 parts, or any other value among 70-80 parts; the ethyl acetate can be 5, 6, 7, 8, 9, or 10 parts, or any other value among 5-10 parts; and the epoxy resin can be 10, 11, 12, 13, 14, or 15 parts, or any other value among 10-15 parts. In this embodiment, by setting the ratio of polyurethane, ethyl acetate, and epoxy resin in the shaping layer 40 within the aforementioned range, the shaping layer 40 simultaneously possesses good flexibility, adhesion, and leveling properties during the carbon fiber layer 50 layup stage. This allows the carbon fiber layer 50 to be stably fixed to the polycarbonate layer surface in large curved areas with a small minimum radius of curvature, preventing slippage, springback, or wrinkling during the layup process. Simultaneously, during the subsequent molding and heating process, ethyl acetate can volatilize or migrate, preventing the shaping layer 40 from forming a barrier interface. Under high temperature and high pressure conditions, the polyurethane and epoxy resin exhibit good interfacial compatibility and bonding with the molten polycarbonate layer, allowing the polycarbonate resin to fully penetrate the interior of the carbon fiber layer 50 for pre-impregnation, thereby significantly improving the bonding stability between the carbon fiber layer 50 and the polycarbonate layer.
[0032] In a further embodiment, the compression molding process includes sequential preheating, heat preservation, pressure holding, cooling, and demolding, ensuring that the heating and pressure processes of the rearview mirror housing 100 are controllable, continuous, and stable at each stage of the molding process. Specifically, the preheating process gradually softens the first polycarbonate layer 10 and the second polycarbonate layer 20, reducing their melt viscosity and preventing displacement or wrinkling of the carbon fiber layer 50 due to sudden temperature increases. The heat preservation process ensures that the polycarbonate layers are fully melted and form a stable resin supply environment on both sides of the carbon fiber layer 50. The pressure holding process promotes the uniform penetration of molten polycarbonate resin into the interior of the carbon fiber layer 50 under pressure, completing sufficient pre-impregnation and eliminating voids in the sandwich structure. The cooling process allows the composite structure to gradually solidify and shape under pressure, locking the large curved surface shape and suppressing internal stress concentration. The demolding process is performed after the material's mechanical properties have stabilized, thereby avoiding warping, delamination, or surface defects. This ensures that even with a large curved surface and a small minimum radius of curvature, a smooth-looking, fiber-twisted, and dimensionally accurate thermoplastic carbon fiber composite automotive rearview mirror housing 100 can still be produced. Here, the demolding process involves removing the first metal mold core 30 and the second metal mold core 60.
[0033] In a further embodiment, the holding pressure of the pressure holding process is any value between 2MPa and 5MPa. That is, the holding pressure of the pressure holding process can be 2MPa, 2.5MPa, 3MPa, 3.5MPa, 4MPa, 4.5MPa, or 5MPa, or any other value between 2MPa and 5MPa. In this embodiment, by limiting the holding pressure of the pressure holding process to the range of 2MPa-5MPa, the molten polycarbonate resin during the compression molding process can stably and uniformly penetrate into the interior of the carbon fiber cloth under pressure. This ensures that the carbon fiber cloth is fully pre-impregnated between the upper and lower polycarbonate layers and effectively removes air from the interlayer, avoiding the formation of pores or dry spots. At the same time, this pressure range can reliably compact and position the carbon fiber cloth, preventing it from slipping, arching, or wrinkling in the large curved area. It also avoids problems such as crushing of the carbon fiber cloth texture, excessive loss of polycarbonate resin, or loss of control over the thickness of the part due to excessive pressure. Thus, under the condition of a large curved surface with a small minimum radius of curvature, it balances sufficient pre-impregnation, appearance quality, and structural stability.
[0034] In a further embodiment, the holding temperature of the pressure holding process is any value between 240℃ and 260℃, that is, the holding temperature can be 240℃, 245℃, 250℃, 255℃, or 260℃, or any other value between 240℃ and 260℃. In this embodiment, by limiting the holding temperature of the pressure holding process to the range of 240℃-260℃, the polycarbonate layer can be fully melted during the pressure holding stage and maintain suitable melt flowability, thereby uniformly penetrating into the interior of the carbon fiber cloth under pressure to complete a stable and sufficient pre-impregnation. Furthermore, the above temperature range is both higher than the melting and flow temperature range of the polycarbonate material, which can avoid the problem of insufficient resin penetration and poor interfacial bonding due to insufficient temperature, and lower than the temperature threshold for significant thermal degradation or performance deterioration of polycarbonate and polyurethane and epoxy resin in the shaping layer 40, thereby preventing material yellowing, embrittlement, or interfacial failure. At the same time, under this temperature condition and with controlled pressure, it is beneficial for polycarbonate resin to achieve stable flow and uniform distribution in the large curved area, reducing the risk of fiber twisting, wrinkling or surface defects caused by excessively high or low viscosity.
[0035] In a further embodiment, the holding time of the pressure holding process is any value between 300s and 600s, that is, the holding time can be 300s, 350s, 400s, 450s, 500s, 550s, or 600s, or any other value between 300s and 600s. In this embodiment, by limiting the holding time of the pressure holding process to the range of 300s to 600s, the polycarbonate layer has sufficient time to remain molten during the pressure holding stage and continuously penetrate into the interior of the carbon fiber cloth under pressure, thereby achieving sufficient pre-impregnation of the carbon fiber cloth and densification of the sandwich structure, avoiding problems such as insufficient resin penetration, weak interfacial bonding, or residual pores due to excessively short holding time.
[0036] In a further embodiment, a release agent is coated on the side of the first metal mold core 30 facing the first polycarbonate layer 10, and a release agent is coated on the side of the second metal mold core 60 facing the second polycarbonate layer 20. This prevents the polycarbonate layer from adhering to or partially binding with the metal mold core during the compression molding process, even when it is in a molten or semi-molten state under high temperature and pressure. This allows for smooth demolding after cooling and setting, avoiding scratches, whitening, or deformation on the surface of the rearview mirror housing 100 caused by forced demolding. Simultaneously, the release agent helps ensure the integrity and smoothness of the part surface during molding, reduces local stress concentration or dimensional deviations caused by mold sticking, further improves the appearance consistency and molding stability of the large-curved rearview mirror housing 100, and helps extend the mold life and improve the yield rate.
[0037] In a further embodiment, the demolding temperature is any value between 70℃ and 90℃, that is, the demolding temperature can be 70℃, 75℃, 80℃, 85℃, or 90℃, or any other value between 70℃ and 90℃. In this embodiment, by limiting the demolding temperature to the range of 70℃-90℃, the thermoplastic carbon fiber composite rearview mirror housing 100 maintains appropriate thermal toughness and dimensional stability after cooling and shaping. Demolding within this temperature range can avoid excessively high part temperatures that could lead to shape springback, surface scratches, or interface instability, while also preventing excessively low temperatures that could cause material embrittlement and cracking, delamination, or edge chipping during demolding. At the same time, this demolding temperature range is beneficial for releasing the internal stress accumulated during the molding process, allowing the large curved surface structure to maintain a stable shape and good appearance after demolding.
[0038] The technical solution of this application will be further described below with reference to specific embodiments.
[0039] In some embodiments, a first metal core 30 is first prepared, and a first polycarbonate layer 10 prepared by vacuum forming is snapped onto the surface of the first metal core 30. Then, a shaping layer 40 with a thickness of any value between 0.05mm and 0.10mm is coated on the surface of the first polycarbonate. After that, a carbon fiber layer 50 cut to a preset size is laid on the surface of the shaping layer 40, and a second polycarbonate layer 20 is placed on the surface of the carbon fiber layer 50 to prepare a rearview mirror housing 100 with a stacked arrangement. The second metal core 60 is snapped onto the surface of the second polycarbonate. Finally, the rearview mirror housing 100 is subjected to compression molding, that is, preheating treatment, heat preservation treatment, pressure holding treatment, cooling treatment and demolding treatment are performed in sequence to prepare the automotive rearview mirror housing 100. The thickness of the first polycarbonate layer 10 and the second polycarbonate layer 20 is any value between 0.1 mm and 0.2 mm. The shaping layer 40 contains 70-80 parts of polyurethane, 5-10 parts of ethyl acetate, and 10-15 parts of epoxy resin. The pressure holding process is any value between 2 MPa and 5 MPa. The pressure holding process temperature is any value between 240℃ and 260℃. The pressure holding process time is any value between 300 s and 600 s.
[0040] Example 1 In the preparation method of the automotive rearview mirror housing 100, firstly, a first metal mold core 30 is prepared, and a first polycarbonate layer 10 prepared by vacuum forming is snapped onto the surface of the first metal mold core 30. Next, a shaping layer 40 with a thickness of 0.07 mm is coated on the surface of the first polycarbonate. Then, a carbon fiber layer 50 cut to a preset size is laid on the surface of the shaping layer 40, and a second polycarbonate layer 20 is placed on the surface of the carbon fiber layer 50 to prepare the laminated rearview mirror housing 100. The second metal mold core 60 is snapped onto the surface of the second polycarbonate. Finally, the rearview mirror housing 100 is subjected to compression molding, that is, preheating treatment, heat preservation treatment, pressure holding treatment, cooling treatment and demolding treatment are performed in sequence to prepare the automotive rearview mirror housing 100. The thickness of the first polycarbonate layer 10 and the second polycarbonate layer 20 is 0.15 mm. The shaping layer 40 contains 80 parts of polyurethane, 10 parts of ethyl acetate, and 10 parts of epoxy resin. The pressure holding process is 3 MPa, the pressure holding temperature is 250°C, and the pressure holding time is 500 s.
[0041] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the setting agent consists only of polyurethane.
[0042] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the setting agent is vinyl acetate adhesive.
[0043] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that the setting agent is epoxy resin.
[0044] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that the thickness of the first polycarbonate layer 10 and the second polycarbonate layer 20 is 0.05 mm.
[0045] Comparative Example 5 The only difference between Comparative Example 5 and Example 1 is that the thickness of the shaping layer 40 is 0.01 mm.
[0046] The rearview mirror housings 100 prepared in Example 1 and Comparative Examples 1-5 were subjected to boiling water test, damp heat aging test, weather alternation test and long-term thermal aging test, and the test results are shown in Table 1.
[0047] The boiling test conditions were as follows: 100℃, storage for 2 hours. The damp heat aging test conditions were: relative humidity 40%, temperature 100℃, storage for 240 hours. The climate cycling test included 20 single-cycle programs. Each single-cycle program consisted of: 1. Temperature increasing from 23℃ to 80℃, relative humidity increasing from 30% to 80%, duration 60 minutes; 2. Temperature 80℃, relative humidity 80%, duration 240 minutes; 3. Temperature decreasing from 80℃ to -40℃, relative humidity increasing from 80% to 30%, duration 120 minutes; 4. Temperature -40℃, duration 240 minutes; 5. Temperature increasing from -40℃ to 23℃, T>0℃, humidity controlled at 30%, duration 60 minutes.
[0048] As shown in Table 1, the rearview mirror housing 100 prepared in Example 1 showed no delamination and no surface cracks after water boiling test, damp heat aging test, weathering test, and long-cycle thermal aging test. In contrast, the rearview mirror housings 100 prepared in Comparative Examples 1-5 all showed delamination and surface cracks. This indicates that the preparation method and parameter combination used in Example 1 can significantly improve the interfacial bonding stability and overall structural reliability between carbon fiber and polycarbonate matrix in the thermoplastic carbon fiber composite rearview mirror housing 100. This allows the part to still have excellent aging resistance and delamination resistance under harsh service environments such as long-term water, damp heat, and temperature cycling, thereby improving the environmental tolerance of the rearview mirror housing 100.
[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0050] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A method for producing a housing for an automobile rearview mirror based on a thermoplastic carbon fiber composite material, characterized in that, The preparation method comprises the following steps: a first polycarbonate layer and a second polycarbonate layer with a preset thickness are prepared by a plastic uptake process; the first polycarbonate layer is clamped on the surface of a first metal mold core, and a shaping layer with a thickness of 0.05-0.10 mm is prepared on the surface of the polycarbonate layer; a carbon fiber layer with a preset size is laid on the surface of the shaping layer; the second polycarbonate layer is placed on the surface of the carbon fiber layer to obtain a laminated rearview mirror shell, and a second metal mold core is clamped on the surface of the second polycarbonate layer; the rearview mirror shell is subjected to a compression molding process to obtain the automobile rearview mirror shell; wherein the preset thickness is any value in the range of 0.1-0.2 mm, and the minimum curvature radius of the rearview mirror shell is less than or equal to 50 mm.
2. The preparation method according to claim 1, wherein the polyurethane in the shaping layer is 70-80 parts, ethyl acetate is 5-10 parts, and epoxy resin is 10-15 parts.
3. The preparation method according to claim 2, wherein the compression molding process comprises a preheating process, a holding process, a pressure maintaining process, a cooling process and a demolding process in sequence.
4. The preparation method according to claim 3, wherein the pressure maintaining pressure of the pressure maintaining process is any value in the range of 2-5 MPa.
5. The preparation method according to claim 4, wherein the pressure maintaining temperature of the pressure maintaining process is any value in the range of 240-260℃.
6. The preparation method according to claim 5, wherein the pressure maintaining time of the pressure maintaining process is any value in the range of 300-600 s.
7. The preparation method according to any one of claims 1-6, wherein the side of the first metal mold core facing the first polycarbonate layer is coated with a demolding agent, and the side of the second metal mold core facing the second polycarbonate layer is coated with the demolding agent.
8. The preparation method according to claim 7, wherein the temperature of the demolding process is any value in the range of 70-90℃.