Structural component, method for manufacturing structural component, and electronic device

Abstract

The present application provides a structural component, a method for preparing the structural component, and an electronic device. The structural component includes a substrate and a metal coating layer, the substrate includes an outer surface, and the metal coating layer is provided on the outer surface, wherein the substrate is made of a polymer material having polar groups, the thermal deformation temperature of the polymer material is greater than or equal to 175°C, and the thermal expansion coefficient of the polymer material is less than or equal to 60*10 ‑6 / K. In the structural component shown in this application, the substrate is made of a polymer material having polar groups. The polar groups of the polymer material help to form a strong bonding force with the metal coating layer. The metal coating layer can be formed directly on the outer surface of the substrate without the need to design a base layer between the metal coating layer and the outer surface. This simplifies the preparation process of the structural component and improves the production efficiency of the structural component.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment, and in particular to a structural component, a method for preparing the structural component, and an electronic device. Background Art

[0002] With the continuous advancement of science and technology, electronic devices such as mobile phones are widely used in people's daily lives and work, becoming indispensable daily necessities. In current electronic devices, structural components are often primed on the substrate surface before being plated to achieve a metal-like effect, enhancing the component's aesthetics. This complicates the component preparation process and reduces production efficiency. Summary of the Invention

[0003] The present application provides a structural component, a method for preparing the structural component, and an electronic device, which simplify the preparation process of the structural component and improve the production efficiency of the structural component.

[0004] In a first aspect, the present application provides a structural part, comprising a substrate and a metal coating layer, wherein the substrate comprises an outer surface, and the metal coating layer is provided on the outer surface, wherein the substrate is made of a polymer material having a polar group, the thermal deformation temperature of the polymer material is greater than or equal to 175°C, and the thermal expansion coefficient of the polymer material is less than or equal to 60*10 -6 / K.

[0005] In the structural component described in this application, the substrate is made of a polymer material having polar groups. The polymer material has a high heat deformation temperature and a low thermal expansion coefficient. The polar groups of the polymer material can form a strong bond with the metal atoms in the metal coating layer, resulting in a strong bond between the substrate and the metal coating layer. Therefore, the metal coating layer can be formed directly on the outer surface of the substrate, eliminating the need for a primer layer between the metal coating layer and the outer surface. This simplifies the manufacturing process of the structural component and improves its production efficiency. Furthermore, since the primer layer does not need to be sprayed, the production process of the structural component does not require the use of large amounts of solvents, reducing pollution caused by the structural component manufacturing process.

[0006] Furthermore, during the formation of the metal coating layer, the substrate will not experience thermal deformation due to the good heat resistance of the polymer material. This not only facilitates the formation of the metal coating layer, improves the bonding strength between the substrate and the metal coating layer, ensures the quality of the metal coating layer, but also effectively improves the yield of the structural component. Furthermore, during the formation of the metal coating layer, the ambient temperature of the substrate in which the metal coating layer is formed will undergo a process of changing from low temperature (such as room temperature) to high temperature (such as the temperature at which metal coating can be performed) and then to low temperature (such as the temperature after cooling). Due to the low thermal expansion coefficient of the polymer material, the substrate will not experience significant expansion or contraction, which helps improve the quality of the metal coating layer and ensures the reliability of the structural component.

[0007] Moreover, since the thermal expansion coefficient of the metal coating layer is 5*10 -6 / K to 25*10 -6 / K, the lower thermal expansion coefficient of the polymer material can not only reduce the difference in thermal expansion coefficient between the substrate and the metal coating layer, but also when the structural parts are used in high or low temperature environments, the deformation difference between the substrate and the metal coating layer will not be too large, which not only helps to improve the structural stability between the substrate and the metal coating layer, but also can avoid cracking of the metal coating layer.

[0008] Among them, the test of the heat deformation temperature of polymer materials meets the international standard ISO 75-1 / -2, and the test of the thermal expansion coefficient of polymer materials meets the international standard ISO 11359.

[0009] In one embodiment, a polymer material weighing 2.16 kg has a flow rate of greater than or equal to 22 g / 10 min at 350°C. The polymer material's fluidity test complies with international standard ISO 1133. In other words, the polymer material used in the substrate has a high melt index and high flowability. This not only helps achieve a high-quality outer surface when the substrate is injection molded, but also helps achieve high-precision molding of the substrate, reducing other appearance defects such as weld marks on the substrate.

[0010] In one embodiment, the outer surface of the substrate has a mirror finish grade of less than or equal to A3, and the outer surface roughness of the substrate is less than or equal to 0.06 μm. In other words, the high quality of the outer surface of the substrate helps to improve the bonding strength between the substrate and the metal coating layer.

[0011] In one embodiment, the surface hardness of the outer surface of the substrate is greater than or equal to F, that is, the outer surface of the substrate has a higher surface hardness, which not only helps to reduce scratches on the substrate, but also prevents cracking of the metal coating layer.

[0012] In one embodiment, the substrate has a notched impact strength greater than or equal to 4 kJ / m 2 The notched impact strength test of the substrate meets the international standard ISO 180. The substrate has high impact strength, which helps to improve the toughness and impact strength of the structural parts and enhance the reliability of the structural parts.

[0013] In one embodiment, the substrate has a flexural modulus greater than or equal to 2500 MPa. The flexural modulus of the substrate is tested in accordance with international standard ISO 178. The high modulus of the substrate not only helps improve the strength and rigidity of the structural component, but also allows the metal coating layer to be directly formed on the outer surface of the substrate without the need for a base coat.

[0014] In one embodiment, the outer surface is provided with a texture pattern comprising a plurality of texture pattern units, and the texture pattern is covered by a metal coating layer. For example, each texture pattern unit has a triangular cross-section. Because the metal coating layer can be formed directly on the outer surface, without a base layer deposited at the sharp corners between adjacent texture pattern units, the sharp corners of each texture pattern unit are not altered, thereby enhancing the metallic texture of the structural component.

[0015] In one embodiment, the polar group is an imide group, a sulfone group, a diphenylsulfone group, or a phthalamide group, wherein the polar group has high temperature resistance.

[0016] In one embodiment, the polymer material includes at least one of polyetherimide, polysulfone plastic, polyethersulfone, polyphenylenesulfone resin, and polyphthalamide, wherein the polymer material complies with international standards ISO 75-1 / -2.

[0017] In one embodiment, the substrate does not contain weld lines.

[0018] In one embodiment, the material of the metal coating layer includes at least one of titanium, chromium, tungsten, vanadium, niobium, zirconium, hafnium, titanium carbide and tungsten carbide.

[0019] In one embodiment, the thickness of the metal coating layer is between 0.2 μm and 8 μm.

[0020] In one embodiment, the metal coating layer has a pencil hardness of ≥2H and an adhesion of ≥4B. The metal coating layer not only provides a high-quality metallic effect but also allows for different colors to be achieved by selecting different metal materials, facilitating the personalized design of structural components. The adhesion of the metal coating layer is measured using a 100-grid test.

[0021] In a second aspect, the present application provides an electronic device, comprising a housing and any one of the above-mentioned structural components, wherein the structural component is mounted on the housing.

[0022] In the electronic device described in this application, the substrate of the structural component is made of a polymer material with polar groups. The polar groups of the polymer material help form a strong bond with the metal coating layer. The metal coating layer can be formed directly on the outer surface of the substrate, eliminating the need for a primer layer between the metal coating layer and the outer surface. This simplifies the manufacturing process of the structural component and improves the production efficiency of the structural component. Furthermore, since the primer layer does not need to be sprayed, the large amount of solvent used in the structural component manufacturing process is eliminated, reducing the pollution caused by the structural component manufacturing process.

[0023] In one embodiment, the structural component is a button, a card holder or a decorative component.

[0024] In one embodiment, the housing has the same structure as the structural member.

[0025] In a third aspect, the present application provides a method for preparing a structural member, comprising:

[0026] The polymer material with polar groups is injection molded to form a substrate, the thermal deformation temperature of the polymer material is greater than or equal to 175 ° C, and the thermal expansion coefficient of the polymer material is less than or equal to 60*10 -6 / K, wherein the substrate comprises an outer surface;

[0027] A metal plating film is formed on the outer surface.

[0028] In the method for preparing a structural component disclosed in this application, a metal coating layer is directly formed on the outer surface of a substrate. This method can easily produce highly refined structural components with a simulated metal appearance. These structural components have high gloss, good flatness, excellent reliability, and strong product performance. They are low-cost and lightweight. The metal coating layer and the substrate are firmly bonded, exhibit excellent wear resistance, and are not prone to cracking or falling off. The structural components prepared by this method combine a refined appearance with a light weight, and have strong product performance. Furthermore, the structural components prepared using this method have high strength, good toughness, good dimensional stability, and excellent chemical resistance.

[0029] In one embodiment, in the step of forming a metal coating on the outer surface, the metal coating is formed using a physical vapor deposition process. Exemplarily, the metal coating layer is formed using a high-temperature sputtering coating process. Not only does the metal coating layer have high purity and good density, and has strong bonding with the substrate, which helps improve the reliability of the structural component, but the high-temperature sputtering coating process is also simpler and pollution-free compared to conventional vacuum non-conductive coating processes used to form metal coating layers. Furthermore, the non-conductive vacuum coating process is often used for surface decoration of glass-fiber-filled polycarbonate resin parts. Using a physical vapor deposition process can eliminate three spraying steps. Parts using non-conductive vacuum coating are particularly prone to resin accumulation and fat edges, which are not conducive to achieving high-quality metallization effects.

[0030] In one embodiment, in the step of injection molding a polymer material having polar groups to form a substrate, the mold temperature of the injection mold is between 135°C and 170°C, the temperature of the polymer material is between 330°C and 400°C, the injection pressure of the polymer material into the injection mold is between 700 bar and 1500 bar, and the injection speed is greater than or equal to 20 mm / s to improve the surface quality of the substrate.

[0031] In one embodiment, the polymer material is injected into the injection mold by a single-point injection method, which helps to reduce appearance defects such as weld lines on the outer surface of the substrate and improve the surface quality of the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be described below.

[0033] Figure 1 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0034] Figure 2 yes Figure 1 A schematic diagram of the back structure of the electronic device shown;

[0035] Figure 3 yes Figure 2 A schematic cross-sectional view of a structural component in the electronic device shown in the first embodiment;

[0036] Figure 4 yes Figure 3 An enlarged structural diagram of area A in the structural member shown;

[0037] Figure 5 yes Figure 2 A schematic cross-sectional view of a structural component in the electronic device shown in the second embodiment;

[0038] Figure 6 yes Figure 5 An enlarged structural diagram of area B in the structural member shown;

[0039] Figure 7 yes Figure 2 A schematic cross-sectional view of a structural component in the electronic device shown in the third embodiment;

[0040] Figure 8 yes Figure 2 A schematic cross-sectional view of a structural component in the electronic device shown in the fourth embodiment;

[0041] Figure 9 This is a process flow chart of a method for preparing a structural part provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0043] See also Figure 1 and Figure 2 , Figure 1 is a structural diagram of an electronic device 1000 provided in an embodiment of the present application. Figure 2 yes Figure 1 A schematic diagram of the back structure of the electronic device 1000 is shown.

[0044] The electronic device 1000 can be an electronic product such as a mobile phone, a tablet computer, a laptop computer, a car computer, a smart watch, a smart bracelet, a POS terminal (point of sales terminal), etc. Next, the embodiment of the present application is described by taking the electronic device 1000 as an example of a mobile phone. For the convenience of description, the width direction of the electronic device 1000 is defined as the X-axis direction, the length direction of the electronic device 1000 is defined as the Y-axis direction, and the thickness direction of the electronic device 1000 is defined as the Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other.

[0045] The electronic device 1000 includes a shell 100, a display module 200, a circuit board 300, a processor (not shown), a camera module 400, a button 500, a card tray 600 and a decorative part 700. The display module 200, the circuit board 300, the processor, the camera module 400, the button 500, the card tray 600 and the decorative part 700 are all installed on the shell 100.

[0046] The housing 100 includes a frame 110 and a back cover 120, which is mounted on the frame 110. The frame 110 may be the middle frame of the electronic device 1000, and the back cover 120 may be the battery cover of the electronic device 1000. In other embodiments, the frame 110 may also be another structural member in the electronic device 1000 that serves as a support.

[0047] The frame 110 is provided with a button hole 1101 and a card holder hole 1102. The openings of the button hole 1101 and the card holder hole 1102 are both located on the circumference of the frame 110 (not marked in the figure). The button hole 1101 and the card holder hole 1102 are both recessed from the circumference of the frame 110 toward the inner side of the frame 110, and pass through the frame 110 to connect the inner and outer sides of the frame 110. Among them, the button hole 1101 is located on the left side of the frame 110, and the card holder hole 1102 is located on the bottom side of the frame 110. In some other embodiments, the button hole 1101 may also be located on the right side, top side or bottom side of the frame 110, and / or the card holder hole 1102 may also be located on the top side, left side or right side of the frame 110.

[0048] It should be noted that the directional terms such as “top”, “bottom”, “upper”, “lower”, “left” and “right” in this application are referenced to the attached Figure 1 The description of the orientations shown, with the positive direction of the Y axis as the "top", the negative direction of the Y axis as the "bottom", the positive direction of the Z axis as the "up", the negative direction of the Z axis as the "down", the positive direction of the X axis as the "right", and the negative direction of the X axis as the "left", does not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present application.

[0049] The back cover 120 is mounted on one side of the frame 110. Exemplarily, the back cover 120 can be mounted on the frame 110 in a detachable manner to facilitate the repair and replacement of internal components or modules of the electronic device 1000. The back cover 120 is provided with a avoidance hole (not shown), which is located on the top side of the back cover 120. The opening of the avoidance hole is located on the upper surface of the back cover 120 (not marked in the figure). The avoidance hole is recessed in the direction (negative direction of the Z axis in the figure) from the upper surface of the back cover 120 to the lower surface (not marked in the figure) of the back cover 120, and passes through the lower surface of the back cover 120. That is, the avoidance hole passes through the back cover 120 along the thickness direction of the back cover 120.

[0050] The display module 200 is mounted on one side of the housing 100. Specifically, the display module 200 is mounted on the other side of the frame 110. That is, the display module 200 is mounted on the side of the frame 110 that is away from the back cover 120. In other words, the display module 200 and the back cover 120 are respectively mounted on opposite sides of the frame 110. When the user uses the electronic device 1000, the display module 200 is placed toward the user, and the back cover 120 is placed away from the user. Among them, the display module 200 can be a display screen such as LCD (liquid crystal display) or OLED (organic light-emitting diode), and is used to display information such as images or text.

[0051] The circuit board 300, the processor and the camera module 400 are all installed on the inner side of the housing 100. The processor can be installed on the circuit board 300 and electrically connected to the circuit board 300. Among them, the circuit board 300 can be the mainboard of the electronic device 1000, and the processor can be the CPU (central processing unit) of the electronic device 1000. The camera module 400 is installed on the top side of the housing 100 and is electrically connected to the circuit board 300 to achieve electrical connection with the processor. Among them, the camera module 400 can serve as a rear camera module of the electronic device 1000, and the camera surface of the camera module 400 (not shown) can be exposed relative to the avoidance hole of the rear cover 120. The camera module 400 can receive the information acquisition signal sent by the processor through the circuit board 300, and collect light outside the electronic device 1000 through the camera surface to form corresponding image data.

[0052] The button 500 and the card tray 600 are both mounted on the frame 110. Specifically, the button 500 is mounted in the button hole 1101, and the card tray 600 is mounted in the card tray hole 1102. The button 500 can be a function button such as the power button, volume button, or lock button of the electronic device 1000, and the card tray 600 can hold a SIM card (Subscriber Identity Module) or a TF card (Trans-flash Card).

[0053] In this embodiment, the decorative piece 700 may be a camera decorative piece. The decorative piece 700 is mounted on the back cover 120 and covers the camera module 400. This not only protects the camera module 400 but also enhances the aesthetics of the electronic device 1000. For example, the decorative piece 700 is annular in shape. In other embodiments, the decorative piece 700 may also be another decorative piece for the electronic device 1000. For example, the decorative piece 700 may be an earpiece decorative piece, mounted in the earpiece hole of the frame 110.

[0054] It is understood that the housing 100, button 500, card tray 600, and decorative element 700 are all structural components 800 of the electronic device 1000 and all contribute to the aesthetic appeal of the electronic device 1000. Therefore, during the fabrication of the structural components 800, a metal coating layer is often formed using a coating process to achieve a metallic effect, thereby enhancing the aesthetic appeal of the electronic device 1000. Next, the structural components 800 of the electronic device 1000 will be described in detail, using the decorative element 700 as an example.

[0055] See also Figure 3 and Figure 4 , Figure 3 yes Figure 2The cross-sectional structure diagram of the structural component 800a in the electronic device 1000 in the first embodiment is shown. Figure 4 yes Figure 3 An enlarged structural diagram of region A in the structural member 800a is shown.

[0056] In this embodiment, the structural member 800a includes a substrate 10a, a base layer 20a, and a metal coating layer 30a. The substrate 10a includes an outer surface 101a, the base layer 20a is provided on the outer surface 101a, and the metal coating layer 30a is provided on the surface of the base layer 20a facing away from the outer surface 101a. Specifically, the outer surface 101a is provided with a texture pattern, the texture pattern includes a plurality of texture pattern units 12a, and the base layer 20a covers the plurality of texture pattern units 12a. Exemplarily, each texture pattern unit 12a is in the shape of a quadrangular pyramid, and the cross-section of each texture pattern unit 12a is triangular. It should be noted that the texture pattern is part of the substrate 10a, and the texture pattern is formed by performing a shape processing on the outer surface 101a of the substrate 10a.

[0057] The substrate 10a is made of conventional engineering plastics. For example, the conventional engineering plastics may be one or more of polycarbonate (PC), polyacrylic acid (PA), acrylonitrile butadiene styrene (ABS), and a composite of polycarbonate and acrylonitrile butadiene styrene.

[0058] It should be noted that in the above-described embodiment, due to the characteristics of conventional engineering plastics, which lack polar groups and have a high coefficient of thermal expansion, the bonding between conventional engineering plastics and the metal atoms in the metal coating layer 30a is poor. Consequently, when the metal coating layer 30a is formed on the outer surface 101a of the substrate 10a, the adhesion of the metal coating layer 30a is poor, which affects the reliability of the structural component 800a. Therefore, it is often necessary to first prime the outer surface 101a of the substrate 10a to form the base layer 20a, and then use a nonconductive vacuum metallization (NCVM) process to form the metal coating layer 30a on the surface of the base layer 20a facing away from the substrate 10a. The manufacturing process for the structural component 800a is complex, resulting in low production efficiency. Furthermore, the spraying process for forming the base layer 20a requires the use of a large amount of solvent, resulting in significant pollution. In addition, since the base layer 20a is often formed by solidifying liquid resin, due to the good fluidity of the liquid resin, it will accumulate at the sharp corner position S1a between two adjacent texture pattern units 12a, resulting in resin accumulation, and the sharp corner position S2a of the texture pattern unit 12a will produce a sudden change, etc. After the liquid resin is subsequently solidified to form the base layer 20a, the base layer 20a will reduce the metal texture of the structural part 800a.

[0059] It should be understood that when the structural component 800a is used in an electronic device, the outer surface 101a of the substrate 10a is the surface of the substrate 10a facing the outside of the electronic device 1000, that is, the outer surface 101a of the substrate 10a is the surface of the substrate 10a facing away from the inside of the electronic device 1000, and the description of the "outer surface" in this application document can be understood in the same way.

[0060] See also Figure 5 and Figure 6 , Figure 5 yes Figure 2 The cross-sectional structure diagram of the structural component 800 in the electronic device 1000 in the second embodiment is shown. Figure 6 yes Figure 5 An enlarged structural diagram of area B in the structural member 800 is shown.

[0061] The structural member 800 includes a substrate 10 and a metal coating layer 20. The substrate 10 includes an outer surface 101, and the metal coating layer 20 is provided on the outer surface 101. Specifically, the outer surface 101 is provided with a texture pattern, and the texture pattern includes a plurality of texture pattern units 12, and the metal coating layer 20 covers the texture pattern. In this embodiment, the substrate 10 is made of a polymer material having a polar group. Among them, the polar group has high temperature resistance, and the polar group can be an imide group, a sulfone group, a diphenyl sulfone group, or a phthalamide group. It should be noted that, in some other embodiments, the substrate 10 may not include the texture pattern unit 12, and this application does not impose specific restrictions on this.

[0062] Among them, the polymer material is special engineering plastics, and the special engineering plastics can be at least one of polyetherimide (PEI), polysulfone (PSU), polyethersulfone (PES), polyphenylene sulfone resin (PPSU) and polyphthalamide (PPA).

[0063] It should be noted that the substrate 10 is made of a non-crystalline specialty engineering plastic. The polar groups in the specialty engineering plastic can form a strong bond with the metal coating layer 20. The strong bond between the substrate 10 and the metal coating layer 20 allows the metal coating layer 20 to be formed directly on the outer surface 101 of the substrate 10, eliminating the need for a primer layer between the metal coating layer 20 and the outer surface 101. This not only simplifies the manufacturing process of the structural component 800 and improves the production efficiency of the structural component 800, but also eliminates the need for spraying to form a primer layer, eliminating the need for large amounts of solvents during the manufacturing process of the structural component 800, thereby reducing pollution caused by the manufacturing process of the structural component 800. Furthermore, since the metal coating layer 20 can be formed directly on the outer surface 101, there is no primer layer accumulated at the sharp corner S1 between two adjacent texture pattern units 12, and the sharp corner S2 of the texture pattern unit 12 is not staggered, which helps to enhance the metallic texture of the structural component 800.

[0064] The flow rate of a polymer material weighing 2.16 kg at a temperature of 350 degrees Celsius is greater than or equal to 22 g / min. The flowability test of the polymer material used in substrate 10 meets the international standard ISO 1133. In other words, the polymer material used in substrate 10 has a high melt index and high flowability. When injection molding substrate 10, it not only helps to obtain a high-quality outer surface, but also helps to achieve high-precision molding of substrate 10, which can reduce other appearance defects such as weld marks on substrate 10. It is understood that the flowability of the polymer material can be adjusted by controlling the molecular weight and adding plasticizers.

[0065] The heat deformation temperature of the polymer material used in the substrate 10 is greater than or equal to 175 degrees Celsius. The heat deformation temperature test of the polymer material used in the substrate 10 meets the international standard ISO 75-1 / -2. In other words, the polymer material used in the substrate 10 has high heat resistance. When the polymer material is used to form the substrate 10 by injection molding, high-temperature and high-speed injection molding can be performed to obtain a substrate 10 with high surface quality. In addition, the good heat resistance helps the substrate 10 to be sputtered at high temperature to form a metal coating layer 20 in the later stage. Moreover, during the formation process of the metal coating layer 20, due to the high heat resistance of the polymer material, the substrate 10 will not be thermally deformed. Not only can the metal coating layer 20 be better formed on the outer surface 101, the bonding force between the substrate 10 and the metal coating layer 20 is improved, the quality of the metal coating layer 20 can be guaranteed, and the yield of the metal coating layer 20 can also be improved. The mirror effect grade of the outer surface of the substrate 10 is less than or equal to A3, and the roughness Ra is less than or equal to 0.06μm. The high surface quality of the substrate 10 helps to improve the bonding strength between the substrate 10 and the metal coating layer 20 .

[0066] In addition, the surface hardness of the outer surface of the substrate 10 is greater than or equal to F, that is, the outer surface of the substrate 10 has a high surface hardness, which not only helps to reduce scratches on the substrate 10, but also avoids cracking of the metal coating layer 20. It should be noted that the notched impact strength of the substrate 10 is greater than or equal to 4 kJ / m2. Among them, the notched impact strength test of the substrate 10 meets the international standard ISO 180. The substrate 10 has a high impact strength, which helps to improve the toughness and impact strength of the structural component 800 and improve the reliability of the structural component 800. The flexural modulus of the substrate 10 is greater than or equal to 2500 MPa. Among them, the flexural modulus test of the substrate 10 meets the international standard ISO 178. The substrate 10 has a high modulus, which not only helps to improve the strength and rigidity of the structural component 800, but also allows the metal coating layer 20 to be directly formed on the outer surface 101 of the substrate 10 without designing a base layer.

[0067] The thermal expansion coefficient of polymer materials is less than or equal to 60*10 -6 / K. Among them, the test of the thermal expansion coefficient of the polymer material meets the international standard ISO 11359. The thermal expansion coefficient of the polymer material is relatively low. It should be noted that during the formation of the metal coating layer 20, the ambient temperature of the substrate 10 where the metal coating layer 20 is formed will experience a process from low temperature (such as room temperature) to high temperature (such as the temperature at which metal coating can be performed) and then to low temperature (such as the temperature after cooling). Due to the low thermal expansion coefficient of the polymer material, the substrate 10 will not expand or contract significantly, which helps to improve the quality of the metal coating layer 20 and ensure the reliability of the structural component 800. Moreover. Since the thermal expansion coefficient of the metal coating layer 20 is 5*10 -6 / K to 25*10 -6 / K, the lower thermal expansion coefficient of the polymer material can not only reduce the difference in thermal expansion coefficient between the substrate 10 and the metal coating layer 20, but also when the structural component 800 is used in a high temperature or low temperature environment, the deformation difference between the substrate 10 and the metal coating layer 20 will not be too large, which helps to improve the structural stability between the substrate 10 and the metal coating layer 20 and avoid cracking of the metal coating layer 20.

[0068] In this embodiment, the material of the metal coating layer 20 includes at least one of titanium, chromium, tungsten, vanadium, niobium, zirconium, hafnium, titanium carbide, and tungsten carbide. The thickness of the metal coating layer ranges from 0.2 μm to 8 μm, with a pencil hardness of ≥ 2H and an adhesion of ≥ 4B. The metal coating layer 20 not only provides a high-quality metallic effect, such as imitating stainless steel, but also allows for different colors to be achieved by selecting different metal materials, facilitating the personalized design of the structural component 800. The adhesion of the metal coating layer 20 is measured using a 100-grid test.

[0069] See also Figure 7 , Figure 7 yes Figure 2 FIG. 1 is a schematic cross-sectional view of the structure of the structural component 800 in the electronic device 1000 in the third embodiment.

[0070] The structural member 800 shown in this embodiment differs from the structural member 800 shown in the second embodiment described above in that the structural member 800 further includes a topcoat layer 30, which is disposed on the surface of the metal coating layer 20 facing away from the substrate 10. The topcoat layer 30 not only protects the metal coating layer 20 and the substrate 10 but also serves as a decoration, enhancing the aesthetic appearance of the structural member 800.

[0071] See also Figure 8 , Figure 8 yes Figure 2 FIG. 1 is a schematic cross-sectional view of the structure of the structural component 800 in the electronic device 1000 in the fourth embodiment.

[0072] The difference between the structural part 800 shown in this embodiment and the structural part 800 shown in the third embodiment mentioned above is that the structural part 800 can also include a color paint layer 40, which is arranged on the surface of the metal coating layer 20 away from the substrate 10, and the topcoat layer 30 is arranged on the surface of the color paint layer away from the metal coating layer 20.

[0073] In the electronic device 1000 shown in this embodiment, the substrate 10 of the structural component 800 is made of a polymer material having polar groups. The polymer material has high heat resistance and a low thermal expansion coefficient. A metal coating layer 20 can be directly formed on the outer surface 101 of the substrate 10 to achieve an appearance comparable to metal, such as an appearance imitating stainless steel, without the need to design a base layer. This not only simplifies the preparation process of the structural component 800 and improves the production efficiency of the structural component 800, but also reduces the production cost and weight of the structural component 800.

[0074] See also Figure 9 , Figure 9 This is a process flow chart of a method for preparing a structural part provided in an embodiment of the present application.

[0075] The present application provides a method for preparing a structural component, which is used to prepare the structural component 800. The method for preparing the structural component includes step S1 and step S2.

[0076] Step S1, injection molding a polymer material having polar groups to form a substrate 10. The polymer material has a thermal deformation temperature greater than or equal to 175°C, and a thermal expansion coefficient less than or equal to 60*10 -6 / K, substrate 10 includes an outer surface 101. In this embodiment, outer surface 101 is provided with a texture pattern, and the texture pattern includes a plurality of texture pattern units 12. Exemplarily, texture pattern units 12 are in the shape of quadrangular pyramids, and the cross-section of texture pattern units 12 is triangular. The polymer material may be plastic particles. Exemplarily, the polymer material is a special engineering plastic, and the special engineering plastic may be at least one of polyetherimide, polysulfone plastic, polyethersulfone, polyphenylene sulfone resin, and polyphthalamide.

[0077] Specifically, the polymer material is melted and plasticized, then injected into a plastic structural component mold, and then injection molded at high temperature and high speed to obtain a substrate 10 with high surface quality. Substrate 10 does not have a weld line. The thickness of substrate 10 is greater than or equal to 0.35 mm, and the mirror finish grade of the outer surface of substrate 10 is less than or equal to A3, with a roughness Ra less than or equal to 0.06 μm. In other embodiments, the thickness of substrate 10 may also be greater than or equal to 0.25 mm.

[0078] It should be noted that during the injection molding process of substrate 10, the mold is preferably a three-plate mold with hot-to-cold runners. The mold can be an electroformed insert, and the mold surface is high-polished to a mirror finish of less than or equal to A3 and a roughness Ra of less than or equal to 0.06 μm. Furthermore, the polymer material is injected into the injection mold using a single-point injection method to avoid weld lines or deformation of substrate 10, thereby improving the surface quality of substrate 10. Specifically, the plastic particles are preferably dried at 140°C / 6 hours, the injection mold temperature (i.e., mold temperature) is between 135°C and 170°C, the polymer material temperature (i.e., material temperature) is between 330°C and 400°C, the polymer material injection pressure into the injection mold is between 700 bar and 1500 bar, and the injection speed (i.e., shot velocity) is greater than or equal to 20 mm / s, thereby improving the surface quality of substrate 10.

[0079] The polymer material weighing 2.16 kg has a fluidity of greater than or equal to 22 g / min at a temperature of 350 degrees Celsius, facilitating single-point injection molding of substrate 10. The fluidity test of the polymer material used in substrate 10 meets the international standard ISO 1133. In other words, the polymer material used in substrate 10 has a high melt index and high flow properties, which not only facilitates high-precision molding of substrate 10 but also helps achieve a high-quality outer surface, reducing weld lines and other cosmetic defects on the outer surface of substrate 10.

[0080] Step S2: Forming a metal coating layer 20 on the outer surface 101. The material of the metal coating layer 20 includes at least one of titanium, chromium, tungsten, vanadium, niobium, zirconium, hafnium, titanium carbide, and tungsten carbide. Exemplarily, the thickness of the metal coating layer 20 is 0.2 μm to 8 μm, the pencil hardness of the metal coating layer 20 is ≥ 2H, and the adhesion of the metal coating layer 20 is ≥ 4B. The metal coating layer 20 not only has a high-quality metallic effect, but also can be obtained in different colors by selecting different metal materials, which helps to improve the appearance of the structural component 800. The adhesion of the metal coating layer 20 is measured using a 100-grid test.

[0081] Specifically, the substrate 10 is placed in a vacuum coating machine for high-temperature sputtering coating to form a metal coating layer 20 on the outer surface 101. Exemplarily, physical vapor deposition (PVD) is used to form the metal coating layer 20. It should be noted that since the polymer materials used in the substrate 10 are all non-crystalline special engineering plastics, the polar groups of the non-crystalline special engineering plastics help the substrate 10 to form a strong bonding force with the metal coating layer 20, so the physical vapor deposition process can be used directly on the outer surface 101 for coating. Moreover, since the thermal deformation temperature of the polymer material used in the substrate 10 is greater than or equal to 175°C, that is, the polymer material used in the substrate 10 has high temperature resistance, it is helpful for the substrate 10 to undergo high-temperature sputtering coating. In addition, since the thermal expansion coefficient of the polymer material used in the substrate 10 is less than or equal to 60*10 -6 / K, that is, the polymer material has a low thermal expansion coefficient. The low thermal expansion coefficient of the substrate 10 not only reduces the difference in thermal expansion coefficients between the substrate 10 and the metal coating layer 20, thereby improving the structural stability between the substrate 10 and the metal coating layer 20, but also prevents cracking of the metal coating layer 20.

[0082] It should be noted that the high-temperature sputtering coating process is used to form the metal coating layer 20. Not only does the metal coating layer 20 have high purity and good density, but it also has strong bonding with the substrate 10, which helps to improve the reliability of the structural part 800. In addition, compared with the conventional vacuum non-conductive coating process used to form the metal coating layer, the high-temperature sputtering coating process is simpler and pollution-free. Furthermore, the non-conductive vacuum coating process is often used for surface decoration of glass fiber-filled polycarbonate (PC) resin parts. The use of physical vapor deposition process can eliminate three spraying steps. In particular, parts using non-conductive vacuum coating are prone to oil accumulation and fat edges, which is not conducive to achieving high-quality metallization effects.

[0083] In some other embodiments, the outer surface 101 of the substrate 10 may be directly coated by physical vapor deposition, or the outer surface 101 of the substrate 10 may be coated by vacuum non-conductive plating, ordinary spraying, water plating or other processes, and this application does not impose any specific restrictions on this.

[0084] It should be noted that the method for preparing a structural component may further include step S3 of post-processing the metal coating layer 20 and the substrate 10. Specifically, the substrate 10 formed with the metal coating layer 20 may be post-processed by computer numerical control (CNC) machining or sprayed with a transparent topcoat according to actual product requirements.

[0085] The method for preparing a structural component shown in the embodiment of the present application directly forms a metal coating layer 20 on the outer surface 101 of a substrate 10. This method can easily produce a highly refined structural component 800 with a simulated metal appearance. The structural component 800 has high gloss, good flatness, excellent reliability, strong product performance, low cost, and is lightweight. The metal coating layer 20 and the substrate 10 are firmly bonded, have excellent wear resistance, and are not prone to cracking or falling off. The structural component 800 prepared by this method combines a refined appearance with a light weight, and has strong product performance. Moreover, the structural component 800 prepared by this method has high strength, good toughness, good dimensional stability, and excellent chemical resistance.

[0086] The above description is only a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application; the embodiments of this application and the features of the embodiments can be combined with each other unless there is a conflict. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An electronic device, characterized in that: include: middle frame; A battery cover, mounted on the middle frame; A camera decorative part, the camera decorative part is mounted on the battery cover; The camera decorative part includes a substrate and a metal coating layer, wherein the metal coating layer is provided on the outer surface of the substrate, the substrate includes a polymer material having a polar group, the thermal deformation temperature of the polymer material is greater than or equal to 175°C, and the thermal expansion coefficient of the polymer material is less than or equal to 60*10 -6 / K, tested according to international standard ISO 1133, the flow rate of the polymer material at a pressure weight of 2.16 kg and 350° C. is greater than or equal to 22 g / 10 min.

2. The electronic device according to claim 1, wherein The mirror effect grade of the outer surface of the substrate is less than or equal to A3, and the outer surface roughness Ra of the substrate is less than or equal to 0.06 μm.

3. The electronic device according to claim 1 or 2, characterized in that The outer surface of the substrate is provided with a texture pattern, and the metal coating layer covers the texture pattern.

4. The electronic device according to claim 3, wherein: The texture pattern includes a plurality of texture pattern units, and a cross section of each of the texture pattern units is triangular.

5. The electronic device according to claim 1, wherein The notched impact strength of the substrate is greater than or equal to 4 kJ / m 2 .

6. The electronic device according to claim 1, wherein: The flexural modulus of the substrate is greater than or equal to 2500 MPa.

7. The electronic device according to claim 1, wherein: The adhesion of the metal coating layer is greater than or equal to 4B.

8. The electronic device according to claim 1, wherein: The thickness of the metal coating layer is between 0.2 μm and 8 μm.

9. The electronic device according to claim 1, wherein: The pencil hardness test of the metal coating layer is ≥2H.

10. The electronic device according to claim 1, wherein The polar group is an imide group, a sulfone group, a diphenylsulfone group or a phthalamide group.

11. The electronic device according to claim 10, characterized in that The polymer material includes at least one of polyetherimide, polysulfone plastic, polyethersulfone, polyphenylene sulfone resin and polyphthalamide.

12. The electronic device according to claim 1, wherein The material of the metal coating layer includes at least one of titanium, chromium, tungsten, vanadium, niobium, zirconium, hafnium, titanium carbide and tungsten carbide.

13. The electronic device according to claim 1, wherein The substrate is prepared by a single-point glue injection method.

14. The electronic device according to claim 1, wherein The substrate does not contain weld lines.

15. The electronic device according to claim 1, wherein The metal coating is formed by a physical vapor deposition process.

16. The electronic device according to claim 1, wherein The camera decorative component further includes a topcoat layer, which is disposed on a surface of the metal coating layer facing away from the substrate.

17. The electronic device according to claim 1, wherein: The camera decorative component further includes a color paint layer and a top paint layer. The color paint layer is arranged on the surface of the metal coating layer away from the substrate, and the top paint layer is arranged on the surface of the color paint layer away from the metal coating layer.

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