Plastic structural member, preparation method therefor and electronic device

Abstract

The present application relates to the technical field of terminals, and provides a plastic structural member, a preparation method therefor and an electronic device. The plastic structural member comprises: a plastic substrate and a paint layer provided on the outer surface of the plastic substrate, the paint layer at least comprising a top coat layer; the top coat layer has a plurality of brushed textures distributed at intervals, the depth of the brushed textures being less than or equal to the thickness of the top coat layer; all of the brushed textures are distributed on the outer surface of the top coat layer in full circles, the top coat layer forming the appearance surface of the plastic structural member. Thus, there is no parting line on the outer surface of the plastic substrate of the plastic structural member, and the plurality of brushed textures macroscopically continuously distributed in full circles are provided on at least the top coat layer formed on the outer surface of the plastic substrate. These brushed textures simulate the texture of bushed metal textures, and meet product requirements for good appearance and high quality. Moreover, the top coat layer covers dirt, shrinkage and particles of the plastic substrate, thereby improving the yield and reliability.

Description

Plastic structural member, preparation method thereof and electronic device

[0001] The present application claims priority to the Chinese patent application No. 202411134475.X, filed on August 16, 2024, and entitled "Plastic structural member, preparation method thereof and electronic device", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of terminals, and in particular to a plastic structural member, a preparation method thereof and an electronic device. BACKGROUND

[0003] With the development of technology, electronic devices such as mobile phones are becoming more and more important in people's lives and are being used more and more frequently. For electronic devices, an attractive appearance can improve the satisfaction of users and attract the attention of potential consumers.

[0004] Many ways to improve the appearance of electronic devices are provided in the related art. For some structural members in electronic devices, such as the surface of a middle frame, performing wire drawing processing on the surface is one of the ways.

[0005] Traditional wire drawing processes are mostly directly wire drawing on the surface of a base material to make it a structural member. When the material of the structural member is metal, although a complete circle of wire drawing can be formed, the cost of equipment and process is high, and the cost is expensive. When the material of the structural member is plastic, it is usually impossible to achieve a complete circle of wire drawing, and the appearance effect is poor. SUMMARY

[0006] The present application provides a plastic structural member, a preparation method thereof and an electronic device. By forming wire drawing on the surface of the topcoat layer of the plastic base body and without wire clamping on the outer surface of the plastic base body, the dirt, shrinkage and particles of the plastic base body can be covered by the topcoat layer, which greatly improves the yield and increases the reliability. At the same time, the wire drawing is macroscopically distributed in a complete circle, and also has the texture of imitated metal wire drawing, which meets the needs of high color value and high texture of products.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, a plastic structural member is provided, which includes a plastic base body and a paint layer arranged on the outer surface of the plastic base body. The paint layer includes at least a topcoat layer, which forms the appearance surface of the plastic structural member. The topcoat layer has a plurality of wire drawings distributed at intervals. The depth of the wire drawing is less than or equal to the thickness of the topcoat layer. All the wire drawings are distributed in a complete circle on the outer surface of the topcoat layer.

[0009] The embodiment of the application provides a plastic structural member, at least a surface paint layer is formed on the outer surface of a plastic base body, then the surface paint layer is subjected to wire drawing treatment, a plurality of macroscopically visible whole-circle continuous wire lines are formed, the wire lines have a metal-like texture, the appearance effect of the surface wire drawing of a metal base material can be achieved, and the surface fiber floating problem is avoided, meanwhile, the surface paint layer can also cover dirt, shrinkage and particles and the like of the plastic base body, the product yield is greatly improved, the gloss and reliability of the product are increased, and the requirements of high color value and high texture and the like of the product are met.

[0010] In a possible implementation manner of the first aspect, the material of the surface paint layer comprises polyurethane acrylic resin, ethyl acetate and a photoinitiator; and / or, the hardness range of the surface paint layer with a pencil includes HB-4H; and / or, the thickness range of the surface paint layer includes 15-55 mu m.

[0011] In the implementation manner, the surface paint layer is transparent ultraviolet curing paint, can be quickly cured after irradiation by an ultraviolet lamp, has good wear resistance and a suitable thickness, is convenient for wire drawing, can guarantee that the wire lines do not penetrate the surface paint layer as much as possible, and can guarantee the persistence of the wire lines.

[0012] In a possible implementation manner of the first aspect, the interval range between two adjacent wire lines includes 4-7 mu m; and / or, the maximum surface width range of each wire line includes 1-3 mu m; and / or, the depth range of each wire line includes 10-55 mu m.

[0013] In the implementation manner, by designing the interval, width and depth of the wire lines and the like, various wire lines can be obtained, and the appearance aesthetic degree of the plastic structural member is enriched.

[0014] In a possible implementation manner of the first aspect, when the depth of the wire line is less than the thickness of the surface paint layer, the depth range of the wire line includes 10-50 mu m.

[0015] In the implementation manner, the wire line does not penetrate the surface paint layer, and the performance of the whole plastic structural member is ensured.

[0016] In a possible implementation manner of the first aspect, the paint layer includes a plastic base, a first primer layer, a second primer layer, a plating layer, a color paint layer, and a topcoat layer. The first primer layer is arranged between the plastic base and the second primer layer. The second primer layer is arranged between the first primer layer and the plating layer. The plating layer is arranged between the second primer layer and the color paint layer. The color paint layer is arranged between the plating layer and the topcoat layer. The material of the first primer layer includes a first thermosetting paint, which includes a first thermosetting resin, a first curing agent, a first pigment, a first filler, a first solvent, and a first additive. The thickness of the first primer layer ranges from 10 μm to 30 μm. The material of the second primer layer includes a first ultraviolet curing paint, which includes a first resin, a first monomer, a first photoinitiator, and a first photosensitive additive. The thickness of the second primer layer ranges from 20 μm to 30 μm. The material of the plating layer includes indium. The thickness of the plating layer is less than or equal to 1 μm. The material of the color paint layer includes a second ultraviolet curing paint, which includes a second resin, a second monomer, a second photoinitiator, and a second photosensitive additive. The thickness of the color paint layer ranges from 5 μm to 10 μm.

[0017] In this implementation manner, a plastic structural part with a specific structure can be obtained.

[0018] In a possible implementation manner of the first aspect, the paint layer includes a plastic base, a second primer layer, a color paint layer, and a topcoat layer. The second primer layer is arranged between the plastic base and the color paint layer. The color paint layer is arranged between the second primer layer and the topcoat layer. The material of the second primer layer includes a second thermosetting paint, which can include a second thermosetting resin, a second curing agent, a second pigment, a second filler, a second solvent, and a second additive. The thickness of the second primer layer ranges from 5 μm to 10 μm. The material of the color paint layer includes a third thermosetting paint, which can include a third thermosetting resin, a third curing agent, a third pigment, a third filler, a third solvent, and a third additive. The thickness of the color paint layer ranges from 5 μm to 10 μm.

[0019] In this implementation manner, a plastic structural part with a specific structure can be obtained.

[0020] In a possible implementation manner of the first aspect, the paint layer includes a plastic base, a first primer layer, a second primer layer, a color paint layer, and a topcoat layer, the first primer layer is arranged between the plastic base and the second primer layer, the second primer layer is arranged between the first primer layer and the color paint layer, and the color paint layer is arranged between the second primer layer and the topcoat layer; a material of the first primer layer includes a first thermosetting paint, the first thermosetting paint includes a first thermosetting resin, a first curing agent, a first pigment, a first filler, a first solvent, and a first additive, and a thickness range of the first primer layer includes 10 μm to 15 μm; a material of the second primer layer includes a first ultraviolet curing paint, the first ultraviolet curing paint includes a first resin, a first monomer, a first photoinitiator, and a first photosensitive additive, and a thickness range of the second primer layer includes 20 μm to 30 μm; a material of the color paint layer includes a second ultraviolet curing paint, the second ultraviolet curing paint includes a second resin, a second monomer, a second photoinitiator, and a second photosensitive additive, and a thickness range of the color paint layer includes 5 μm to 10 μm.

[0021] In this implementation manner, a plastic structural part with a specific structure can be obtained.

[0022] In a possible implementation manner of the first aspect, a material of the plastic base includes at least one of polycarbonate, polyamide, polyethylene imine, polycarbonate and glass fiber, polyamide and glass fiber, and polyethylene imine and glass fiber; and / or, a Vickers hardness range of the plastic base includes 60 HV to 90 HV.

[0023] In this implementation manner, the formed plastic structural part can have good hardness, light weight, and strong plasticity.

[0024] In a possible implementation manner of the first aspect, the plastic base is an injection molded part, and an outer surface of the plastic base is free of wire clamps.

[0025] In this implementation manner, the plastic base material is first molded and injection molded through a mold to form a plastic base with wire clamps, and then the wire clamps on the outer surface of the plastic base are removed. Since the outer surface of the plastic base is free of wire clamps, the formed plastic structural part is also free of wire clamps, further improving the appearance delicacy.

[0026] In a possible implementation manner of the first aspect, the plastic structural part includes at least one of a housing of a notebook computer, a middle frame of a mobile phone, a middle frame of a tablet computer, and a battery cover.

[0027] In this implementation manner, the outer surface of the housing of the notebook computer, the middle frame of the mobile phone, the middle frame of the tablet computer, and the battery cover can be seen as a whole continuous wire pattern in macro view, and a metal wire drawing effect is also obtained, and the appearance effect is greatly improved.

[0028] In a second aspect, an electronic device is provided, comprising the plastic structural member as in the first aspect or any possible implementation of the first aspect.

[0029] The electronic device provided by the embodiments of the present application has an outer surface of the plastic structural member on which a whole-circle continuous silk grain can be seen macroscopically, and a metal-drawing-like texture is also obtained, thereby meeting the requirements of high color value and high texture of the electronic device.

[0030] In a third aspect, a preparation method of a plastic structural member is provided, comprising: forming a plastic base body without wire clamping on an outer surface; forming a paint layer on the outer surface corresponding to a wire-drawing area of the plastic base body; wherein the paint layer at least comprises a topcoat layer; performing wire-drawing processing on the topcoat layer to form the plastic structural member; wherein the topcoat layer has a plurality of spaced silk grains, the depth of the silk grain is less than or equal to the thickness of the topcoat layer, all the silk grains are distributed in a whole circle on the outer surface of the topcoat layer, and the topcoat layer forms an appearance surface of the plastic structural member.

[0031] The preparation method of the plastic structural member provided by the embodiments of the present application first forms a plastic base body with wire clamping through a mold forming process and an injection molding process and the like, then removes the wire clamping on the outer surface of the plastic base body, then forms at least a topcoat layer on the outer surface of the plastic base body, and then performs wire-drawing processing on the topcoat layer to form a plurality of whole-circle continuous silk grains that can be seen macroscopically. The silk grains have a metal-drawing-like texture, can achieve the appearance effect of wire-drawing on the surface of a metal base material, and avoid the problem of surface fiber floating. In addition, the topcoat layer can also cover dirt, shrinkage and particles and the like of the plastic base body, thereby greatly improving the product yield, increasing the gloss and reliability of the product, and meeting the requirements of high color value and high texture of the product. In addition, the preparation method of the plastic structural member is simple and easy to implement.

[0032] In a possible implementation of the third aspect, the forming of the plastic base body comprises: using a mold forming and injection molding on a plastic raw material to form a first structural member; wherein the outer surface of the first structural member has wire clamping; and the wire clamping is removed to form the plastic base body.

[0033] In this implementation, the plastic base body without wire clamping on the outer surface can be obtained, thereby ensuring that the silk grain of the plastic structural member has no wire clamping, and the implementation is simple.

[0034] In a possible implementation of the third aspect, the method of removing the wire clamping comprises a grinding process or a computer numerical control process.

[0035] In this implementation, the wire clamping can be effectively removed, and the implementation is simple.

[0036] In a possible implementation manner of the third aspect, the surface paint layer is subjected to the wire drawing treatment to form the plastic structural member, including: subjecting the surface paint layer to the wire drawing treatment by using a wire drawing wheel, and wiping the outer surface of the surface paint layer by using a brightening liquid to form the plastic structural member.

[0037] In this implementation manner, the wire drawing on the outer surface of the surface paint layer can be well achieved, and the outer surface of the surface paint layer can be effectively cleaned by wiping the outer surface of the surface paint layer by the brightening liquid, so that the product appearance surface is brightened and smoothed, the appearance of the plastic structural member is greatly improved, and the plastic structural member has better metal-like texture and high light effect.

[0038] In a possible implementation manner of the third aspect, the wire drawing wheel includes a flying wing wheel, and a material of the flying wing wheel includes resin, nylon and aluminum powder; and / or, a Vickers hardness range of the flying wing wheel includes 60HV-70HV.

[0039] In this implementation manner, the flying wing wheel is not so hard, so that the flying wing wheel can break the outer surface of the surface paint layer to form the wire drawing, and the depth of the wire drawing can be well controlled and will not be too deep, so that the surface paint layer is not broken.

[0040] The embodiments of the present application provide a plastic structural member, a preparation method thereof and an electronic device. The plastic base material is first formed into a plastic base body with a wire through a mold forming and injection molding, then the wire on the outer surface of the plastic base body is removed, then at least a surface paint layer is formed on the outer surface of the plastic base body, and then the surface paint layer is subjected to wire drawing treatment to form a plurality of macroscopically visible whole-circle continuous wire drawings. The wire drawings have a metal-like texture and can achieve the appearance effect of the surface wire drawing of the metal base material, and the surface fiber floating problem is avoided. Meanwhile, the surface paint layer can also cover the dirt, shrinkage and particles of the plastic base body, and the product yield is greatly improved, the gloss and reliability of the product are increased, and the high color value and high texture requirements of the product are met. When applied to the electronic device, the appearance of the electronic device can be greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0041] FIG. 1 is a schematic diagram of the overall structure of an electronic device according to an embodiment of the present application;

[0042] FIG. 2 is a schematic diagram of the split structure of the electronic device of FIG. 1;

[0043] FIG. 3 is a schematic diagram of a metal wheel for wire drawing of a metal base material according to the related art;

[0044] FIG. 4 is a schematic diagram of the structure of the metal base material after the wire drawing in FIG. 3 is completed;

[0045] FIG. 5 is a schematic diagram of a four-face sliding block mold for wire drawing of a plastic base material according to the related art;

[0046] FIG. 6 is a schematic diagram of a prior art upper and lower split mold for drawing a plastic substrate;

[0047] FIG. 7 is a schematic diagram of a four-sided slider clamp according to an embodiment of the present application;

[0048] FIG. 8 is a schematic diagram of a drawing wheel drawing a plastic structure according to an embodiment of the present application;

[0049] FIG. 9 is a schematic diagram of a first structure according to an embodiment of the present application;

[0050] FIG. 10 is a schematic diagram of another first structure according to an embodiment of the present application;

[0051] FIG. 11 is a schematic diagram of yet another first structure according to an embodiment of the present application;

[0052] FIG. 12 is a schematic diagram of a drawing wheel drawing four first structures according to an embodiment of the present application;

[0053] FIG. 13 is a schematic diagram of a thread pattern of a plastic structure according to an embodiment of the present application;

[0054] FIG. 14 is a schematic diagram of a thread pattern of a first surface of a top coat layer according to an embodiment of the present application;

[0055] FIG. 15 is a cross-sectional view of the top coat layer according to an embodiment of the present application;

[0056] FIG. 16 is a cross-sectional view of a plastic structure according to an embodiment of the present application;

[0057] Label: 01 - mobile phone; 100 - display screen; 101 - middle frame; 102 - back shell; 103 - circuit board assembly; 1031 - mainboard; 1032 - electronic components; 104 - battery; 105 - battery cover; 200 - shaft; 201 - metal wheel; 202 - mechanical hand; 203 - metal base material; 204 - metal structural part; 205 - metal wire drawing pattern; 301 - first sliding block; 302 - second sliding block; 303 - third sliding block; 304 - fourth sliding block; 3051 - first splicing area; 3052 - second splicing area; 3053 - third splicing area; 3054 - fourth splicing area; 3011 - first textured surface; 306 - plastic base material; 307 - first plastic base material forming part; 308 - first plastic wire drawing pattern; 309 - first plastic clamping line; 401 - upper die; 402 - lower die; 404 - second plastic base material forming part; 405 - second plastic clamping line; 406 - second plastic wire drawing pattern; 1 - third plastic base material forming part; 2 - fourth plastic base material forming part; 21 - third plastic clamping line; 22 - fourth plastic clamping line; 3 - plastic base; 4 - first structural part; 5 - wire drawing wheel; 6 - fixed rod; 7 - jig rod; 8 - plastic structural part; 9 - wire pattern; 10 - first primer layer; 11 - second primer layer; 12 - plating layer; 13 - color paint layer; 14 - topcoat layer; 141 - first surface of topcoat layer; 15 - anti-fingerprint layer. DETAILED DESCRIPTION

[0058] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " represents the meaning of or, for example, A / B can represent A or B; "and / or" in the text only describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone.

[0059] Hereinafter, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more features, and in the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more, and "at least one" means one or more.

[0060] First, some terms in the embodiments of the present application are explained and described so that those skilled in the art can better understand them.

[0061] 1, Physical vapor deposition (physical vapor deposition, PVD)

[0062] PVD refers to a technology of depositing atoms or ions in a solid target material to the surface of a substrate by evaporation or sputtering of the solid target material in a vacuum environment, to form a thin film with special functions.

[0063] PVD has the advantages of good film-substrate bonding force, uniform and dense film, good controllability of film thickness, wide range of target materials (e.g., metal target material, alloy target material, and ceramic target material, etc.), wide sputtering range, thick film deposition, good repeatability, etc.

[0064] 2. Injection molding

[0065] Injection molding is a production molding method of products, which can be realized by an injection molding machine (referred to as an injection machine or an injection molding machine) and a mold, and is used to make various shaped products from thermoplastic materials, thermosetting materials, etc.

[0066] 3. Spraying

[0067] Spraying refers to a method of dispersing a material to be sprayed, such as paint, into uniform and fine mist droplets by means of pressure or centrifugal force by a spray gun or a disc atomizer, and applying it to the surface of the coated object.

[0068] 4. Anti-fingerprint (AF) layer

[0069] The AF layer uses a special coating material that can effectively absorb the oil and sweat left by fingerprints, making the traces left by fingerprints very weak, and also preventing the traces left by fingerprints from being discovered and copied by others, improving the security and accuracy of fingerprint identification.

[0070] 5. Computerized numerical control (CNC)

[0071] CNC refers to a method of using numerical control machining equipment to process the surface of a workpiece, which usually includes precision machining, CNC machining lathes, CNC machining milling machines, and CNC machining boring and milling machines, etc.

[0072] 6. Wire drawing

[0073] Wire drawing refers to a method of surface treatment of products by mechanical processing, etc., which rubs marks on the surface of the product to form lines, thereby achieving a decorative effect.

[0074] The effect of wire drawing is a permanent, destructive, and irreversible process.

[0075] 7. Molding texturing

[0076] Mold texturing refers to the processing of texture on the mold, usually including laser processing texturing, etc. Laser processing texturing uses a high-energy laser beam to engrave a designed texture on the inner surface of the mold. This processing method is fine and can achieve excellent processing results, and is suitable for the processing of complex molds with irregular surfaces, high precision and high design freedom, etc.

[0077] 8. Non-conductive vacuum metallization (NCVM)

[0078] NCVM refers to a process in which a material is converted into particles under vacuum conditions using specific chemical and physical means, and deposited or adsorbed on the surface of a substrate to form a film.

[0079] 9. Mold

[0080] Mold is a tool or device used in industrial production to produce the desired product by methods such as injection molding, blow molding, extrusion, die casting / forging, smelting, and stamping. In short, it is a tool used to make shaped objects. There are many types of molds, such as four-face slide block molds, and top-and-bottom split molds.

[0081] A four-face slide block mold is composed of four rotatable and connected slide blocks, and the movement of the rotating slide blocks can be controlled by mechanical transmission / hydraulic devices to achieve multi-directional stamping and molding.

[0082] A top-and-bottom split mold includes a movable mold and a fixed mold that are clamped together. The fixed mold directly contacts the structural member for positioning and guiding, and the movable mold can be moved and adjusted for shape processing. Specifically, the movable mold is separated from the fixed mold to remove the workpiece, and when closed, the blank is injected into the mold cavity to form a shape. In addition, the gap between the movable mold and the fixed mold can ensure the position of the blank and prevent friction, avoiding damage to the workpiece.

[0083] 10. Vickers hardness

[0084] Vickers hardness is a standard for indicating the hardness of a material. It refers to the use of a diamond right pyramid indenter with an included angle of 136° between the opposite faces to press into the surface of the material being tested under a specified load. After a certain period of time, the load is removed, and the diagonal length of the indentation is measured. The indentation surface area is then calculated, and finally the average pressure on the indentation surface area is obtained, which is the Vickers hardness value of the material being tested, represented by the symbol HV.

[0085] 11. Plastic

[0086] Plastic, also known as plastic, refers to a plastic (flexible) material or a rigid material formed by cross-linking after processing and molding, which is mainly composed of high molecular weight synthetic resins, and appropriate additives such as plasticizers, stabilizers, flame retardants, lubricants, and colorants.

[0087] The above is a brief introduction to the terms involved in the embodiments of the present application, which will not be described below.

[0088] In order to facilitate understanding of the embodiments of the present application, the application background of the embodiments of the present application will be introduced first.

[0089] The specific type of electronic device is not limited in the embodiments of the present application. In some embodiments, the electronic device of the present application can include a mobile phone, a tablet, a notebook, a wearable device (for example, a smart bracelet, a smart watch, and a headset, etc.), a laptop, a handheld computer, an ultra-mobile personal computer (UMPC), a cellular phone, a personal digital assistant (PDA), an augmented reality (AR) \ virtual reality (VR) device, an internet of things (IOT) device, an in-vehicle electronic device, and can also be a television, a large screen, a printer, a projector, etc.

[0090] The specific form of the above electronic device is not limited in the embodiments of the present application. For convenience, the electronic device is taken as a mobile phone as an example for description.

[0091] Please refer to FIG. 1 and FIG. 2, FIG. 1 is a whole schematic diagram of a mobile phone 01 applicable to some embodiments of the present application, and FIG. 2 is a split schematic diagram of the mobile phone 01 shown in FIG. 1. The mobile phone 01 shown in FIG. 1 and FIG. 2 is taken as a tablet phone as an example for description. In other embodiments, it can also be other types of mobile phones, for example, foldable mobile phones, etc., and the specific type is subject to actual application.

[0092] In the example of FIG. 1 and FIG. 2, the mobile phone 01 can include a display screen 100, a middle frame 101, a back shell 102, a circuit board assembly 103, and a battery 104, etc. It can be understood that FIG. 1 and FIG. 2 and the related drawings below only schematically show some components in the mobile phone 01, and the actual shape, size, position, and structure of these components are not limited by FIG. 1 and FIG. 2 and the drawings below.

[0093] As shown in FIG. 1 and FIG. 2, the display screen 100 is located at one side of the middle frame 101, and the display screen 100 can be used to display images, videos, etc.

[0094] In applications, the display screen 100 can be any one of a liquid crystal display (LCD), an organic light emitting diode (OLED) display screen, a mini light emitting diode (Mini LED) display screen, a micro light emitting diode (Micro LED) display screen, and the like.

[0095] In the embodiment shown in FIG. 1, the electronic device can have a rectangular flat shape, and of course, the electronic device can also have any other shape.

[0096] In addition, when the mobile phone 01 is a foldable mobile phone, the display screen 100 can be a foldable screen, and the actual application is specific.

[0097] Referring to FIG. 2, the back cover 102 is arranged on the side of the middle frame 101 away from the display screen 100, and an internal accommodating space can be formed between the back cover 102 and the middle frame 101, which can be used to accommodate the circuit board assembly 103 and the battery 104 and the like.

[0098] The above-mentioned battery 104 can be used to provide power to the mobile phone 01, such as the display screen 100, the circuit board assembly 103, and the like. In addition, a battery cover 105 is also provided, which can protect the battery 104.

[0099] As shown in FIG. 2, the circuit board assembly 103 can include a main board 1031 and electronic elements 1032 and the like.

[0100] The main board 1031 can be used to carry the electronic elements 1032 and complete signal interaction with the electronic elements 1032. FIG. 2 takes the example of the circuit board assembly 103 including two electronic elements 1032 for illustration, and of course, the number of electronic elements 1032 can not be limited to two, and the actual application is specific.

[0101] In actual applications, the main board 1031 can include a printed circuit board (PCB), a flexible printed circuit (FPC), and the like.

[0102] The electronic element 1032 can include, but is not limited to, a camera, a speaker, a microphone (Mic), a chip, a resistor, a capacitor, an inductor, a potentiometer, a tube, a heat sink, an electromechanical component, a connector, a semiconductor discrete device, a sensor, a power supply, a switch, a micro motor, an electronic transformer, a relay, a subscriber identity module (SIM) card, and the like.

[0103] On the basis described above, the mobile phone 01 can further include a microphone, a speaker, a camera, and other structures, which are not specifically described herein.

[0104] Electronic devices are commonly used by people, and an attractive appearance can improve the satisfaction of users and attract the attention of potential consumers. For some structural parts in electronic devices, for example, the shell of a notebook computer, the middle frame of a mobile phone, the middle frame of a tablet computer, and a battery cover, it is necessary to have a certain degree of aesthetics, so that when it is applied in an electronic device, the aesthetics of the electronic device is improved.

[0105] There are many methods in the related art to improve the aesthetics of the appearance of a structural part. One of them is to perform wire drawing processing on the outer surface of the structural part. The following takes the middle frame 101 of a mobile phone as an example to specifically describe the wire drawing processing, which is not limited to the middle frame 101 of a mobile phone.

[0106] The main materials of the middle frame 101 on the market at present include plastic, metal (for example, aluminum alloy, titanium alloy, etc.), and the like. Among them, plastic has the advantages of low cost, light weight, and strong plasticity; metal has the advantages of lightness, high strength, and good heat dissipation.

[0107] The traditional wire drawing processing is to directly perform wire drawing on the outer surface of the base material after the base material is formed, so that the outer surface of the base material has a silk pattern, and the aesthetics is improved.

[0108] The following gives two examples of directly wire drawing on the outer surface of the base material in the related art.

[0109] Example 1 (wire drawing on the outer surface of a metal base material):

[0110] FIG. 3 shows a scheme of wire drawing on the outer surface of a metal base material 203.

[0111] As shown in FIG. 3, the metal wheel 201 is movably connected to the shaft center 200, and can also rotate around the shaft center 200 along the dashed arrow direction in FIG. 3; and the mechanical arm 202 clamps the metal base material 203 and drives the metal base material 203 to revolve around the metal wheel 201, in the process, the metal wheel 201 rubs the outer surface of the metal base material 203 to draw wires on the outer surface of the metal base material 203, and form the metal structural member 204 shown in FIG. 4, which has a plurality of metal wire drawing lines 205.

[0112] In the application, the metal wheel 201 can be a metal wire drawing wheel, and the material of the metal wheel 201 is metal.

[0113] It should be noted that the metal base material 203 in FIG. 3 can rotate along the arrow direction in FIG. 3; or the metal base material can also be fixed, at this time, the metal wheel needs to rotate along the arrow direction in the drawing while also moving along the surface of the metal base material, so that the surface of the metal base material corresponding to the area to be drawn is drawn.

[0114] In addition, the size of the metal base material 203 is usually larger than that of the final metal structural member 204, so that the metal base material 203 can be processed by CNC to wash away the residual material on the outer surface, and when the metal base material 203 is drawn later, the outer surface of the metal structural member 204 will not have defects such as wire clamping, so that the whole circle of wire lines can be formed, and the whole circle of wire lines is also continuous wire lines in macro view. Therefore, the outer surface of the metal structural member 204 has a non-mirror-like metal luster, and also has a fine hair-like luster, which better retains the metal texture, and the product appearance is more beautiful and high-grade.

[0115] However, the traditional method directly draws wires on the outer surface of the metal base material 203, and the cost is very high whether in process or equipment, which is not conducive to industrial production.

[0116] Example two (drawing wires on the outer surface of a plastic base material):

[0117] The material of the plastic base material can include at least one of polycarbonate (PC), polyamide (PA), and polyethyleneimine (PEI). On this basis, the material of the plastic base material can also contain glass fiber (GF), and specifically, the GF is doped in the PC, or the GF is doped in the PA, or the GF is doped in the PEI.

[0118] Taking the material of the plastic base material as PC+GF as an example, the problems of using the above-mentioned equipment and process to draw wires on the outer surface of the metal base material to draw wires on the surface of the plastic base material are described.

[0119] When the PC and GF particles are sequentially subjected to processes such as melting and injection molding to form a plastic base material, the PC and GF particles (especially the GF particles) may accumulate on the outer surface of the plastic base material at a depth of 1-2 mm due to high temperature during preparation, and microscopically, a plurality of disordered lines are observed. When the metal base material wire drawing equipment shown in FIG. 3 is used for wire drawing, the lines are raised and form relatively rough lines, resulting in invisible or unclear lines, i.e., the surface fiber floating problem. The floating fibers originate from the plastic base material itself, and there is currently no good way to solve this problem.

[0120] Based on the above, the related art attempts to use other equipment and methods to directly draw the outer surface of the plastic base material, and one of them is to draw the plastic base material through a mold. As known, the conventional mold is composed of at least two sub-molds. First, the inner surface of at least one sub-mold is textured, the plastic base material is placed in the mold when all the sub-molds are opened, the plastic base material is drawn when all the sub-molds are closed, and the formed structure is taken out after all the sub-molds are opened. There are many types of molds known, such as four-face slider molds and up-down split molds.

[0121] The following will take four-face slider molds and up-down split molds as examples to explain the direct wire drawing on the outer surface of the plastic base material in detail.

[0122] FIG. 5 shows a scheme for directly drawing the outer surface of the plastic base material using a four-face slider mold.

[0123] First, as shown in FIG. 5a, a four-face slider mold is prepared, which has a first slider 301, a second slider 302, a third slider 303, and a fourth slider 304, which are sequentially spliced together; as shown in FIG. 5b, taking the first slider 301 as an example, a wire is directly drawn on the inner surface of the first slider 301 to form a first textured surface 3011, i.e., the four-face slider mold is textured; as shown in FIG. 5c, the plastic base material 306 is placed in the four-face slider mold, and then the sliders are closed; as shown in FIG. 5d, the first plastic base material forming piece 307 is directly injection molded after the mold is assembled, and the first plastic base material forming piece 307 has a first plastic wire drawing line 308.

[0124] It should be noted that the shape, size, material, etc. of the first slider 301, the second slider 302, the third slider 303, and the fourth slider 304 are not specifically limited, as long as the first slider 301, the second slider 302, the third slider 303, and the fourth slider 304 can be connected. Of course, the number of sliders of the mold is not limited to four, and the actual application is used as a reference.

[0125] The textured surfaces of the second slider 302, the third slider 303 and the fourth slider 304 are not shown in FIG. 5, and the inner surfaces of the second slider 302, the third slider 303 and the fourth slider 304 can be textured or not textured as needed.

[0126] The mold can be textured according to the required first plastic wire drawing texture 308, such as the wire drawing interval, the wire drawing gap, the wire drawing depth, etc. Specifically, laser processing can be used for texturing.

[0127] In addition, the shape of the first plastic base material forming piece 307, the appearance of the first plastic wire drawing texture 308, and the number of the first plastic wire drawing texture 308 shown in FIG. 5d are only examples, and of course are not limited thereto, and can be determined according to the actual process.

[0128] FIG. 6 shows a scheme for drawing wires on the outer surface of a plastic base material using an upper and lower split mold.

[0129] First, as shown in FIG. 6a, an upper and lower split mold and a plastic base material 306 are prepared, the upper and lower split mold includes an upper mold 401 and a lower mold 402 which have been textured; as shown in FIG. 6b, the plastic base material 306 is placed between the upper mold 401 and the lower mold 402, and the upper mold 401 and the lower mold 402 are closed; as shown in FIG. 6c, the upper mold 401 and the lower mold 402 are opened, and a second plastic base material forming piece 404 is taken out, the second plastic base material forming piece 404 has a second plastic wire drawing texture 406.

[0130] It should be noted that only one of the upper mold 401 and the lower mold 402 can be textured according to the actual wire drawing needs.

[0131] Please refer to FIG. 5d and FIG. 6c again, the outer surface of the first plastic base material forming piece 307 has a first plastic wire 309, and the outer surface of the second plastic base material forming piece 404 has a second plastic wire 405, because: as shown in FIG. 7, the first plastic base material forming piece 307 has a first splicing area 3051 between the first slider 301 and the second slider 302, a second splicing area 3052 between the second slider 302 and the third slider 303, a third splicing area 3053 between the third slider 303 and the fourth slider 304, and a fourth splicing area 3054 between the fourth slider 304 and the first slider 301; similarly, the upper mold 401 and the lower mold 402 in FIG. 6 are also spliced, and there is also a splicing area between them, but the drawing example is not shown. These splicing areas will inevitably have gaps, and the gaps will inevitably cause the surface of the plastic base material forming piece to have a wire, i.e., the so-called mold line, which causes the plastic base material to be unable to achieve a macroscopically continuous wire, and the appearance effect is poorer compared with the wire of the metal base material.

[0132] It should be noted that the positions, quantities, directions, etc. of the first plastic thread clamping 309 and the second plastic thread clamping 405 can be determined according to the structure of the mold and the actual process.

[0133] Based on the above, how to consider the cost and effect of wire drawing on the outer surface of the substrate, that is, to form a macroscopic whole-circle continuous wire pattern without thread clamping after wire drawing at a lower cost, is a problem to be solved.

[0134] To solve the above problems, the embodiment of the application provides a plastic structural member. By removing the thread clamping on the surface of the plastic substrate first, the outer surface of the plastic base formed is free of thread clamping. Then, at least a finish layer is formed on the outer surface of the plastic base. At this time, the finish layer can cover the dirt, shrinkage and particles of the plastic base, greatly improving the yield and increasing the reliability. At the same time, the finish layer is drawn, and a whole-circle continuous wire pattern can be seen macroscopically. In addition, the quality of the imitation metal drawing is obtained, which meets the needs of high color value and high quality of the product.

[0135] Please refer to FIGS. 8 to 16 for a detailed introduction to the wire drawing process provided by the embodiment of the application and the plastic structural member formed by the wire drawing process.

[0136] As shown in FIG. 8, the embodiment of the application provides a preparation method of a plastic structural member, which comprises the following steps:

[0137] S10. As shown in FIG. 8a, a third plastic substrate forming member 1 and a fourth plastic substrate forming member 2 are provided respectively.

[0138] Among them, the outer surface of the third plastic substrate forming member 1 has a third plastic thread clamping 21, and the outer surface of the fourth plastic substrate forming member 2 has a fourth plastic thread clamping 22.

[0139] It should be noted that the third plastic substrate forming member 1 can be made by subjecting the plastic substrate 306 in FIG. 5 to a process other than the wire drawing process, and the other steps are the same as in FIG. 5, which will not be repeated here. Similarly, the fourth plastic substrate forming member 2 can be made by subjecting the plastic substrate 306 in FIG. 6 to a process other than the wire drawing process, and the other steps are the same as in FIG. 6, which will not be repeated here.

[0140] In application, the number and position of the third plastic thread clamping 21 and the fourth plastic thread clamping 22 can be determined according to the clamp and the process.

[0141] In applications, the Vickers hardness of the plastic base material can range from 60HV to 90HV. Typically, the Vickers hardness of the plastic base material can range from 60HV to 65HV. For example, the Vickers hardness of the plastic base material can be 60HV, 61HV, 62HV, 63HV, 64HV or 65HV. In this way, the plastic structure formed can have good hardness, light weight and strong plasticity.

[0142] As an example, when the plastic base material is composed of PC+GF, the volume percentage of GF in PC+GF can range from 10% to 50%. For example, the volume percentage of GF in PC+GF can be 10%, 15%, 20%, 30%, 40% or 50%.

[0143] As another example, when the plastic base material is composed of PA+GF, the volume percentage of GF in PA+GF can range from 10% to 50%. For example, the volume percentage of GF in PA+GF can be 15%, 20%, 30%, 40%, 50% or 55%.

[0144] S11. As shown in Figure 8b, the plastic base 3 is formed by removing the plastic lines.

[0145] In applications, the method for removing the plastic lines can include polishing, CNC processing, etc.

[0146] Typically, the third plastic lines 21 on the outer surface of the third plastic base material forming part 1 can be removed by polishing.

[0147] Typically, the fourth plastic lines 22 on the outer surface of the fourth plastic base material forming part 2 can be removed by CNC processing.

[0148] In this way, the plastic base 3 is formed by injection molding, and the outer surface of the plastic base has no plastic lines.

[0149] S12. As shown in Figure 8c, at least a surface paint layer 14 is formed on the surface corresponding to the area to be drawn on the plastic base 3, to obtain the first structure 4.

[0150] It should be understood that, as shown in Figure 8c, only the surface paint layer 14 can be formed on the surface corresponding to the area to be drawn on the plastic base 3 to form a paint layer; or, as shown in Figures 9 to 11, at least one of the first primer layer 10, the second primer layer 11, the plating layer 12 and the color paint layer 13 can be formed on the surface corresponding to the area to be drawn on the plastic base 3 in addition to the surface paint layer 14 to form a paint layer. Of course, this is not limited, and the actual application is subject to change.

[0151] In applications, the material of the topcoat layer 14 can include polyurethane acrylic resin, ethyl acetate and photoinitiator, and the topcoat layer 14 thus formed is ultraviolet (UV) curing paint, which is transparent and can be cured rapidly within a few seconds after irradiation by a UV lamp.

[0152] Meanwhile, the pencil hardness of the topcoat layer 14 ranges from HB to 4H, and typically, the pencil hardness of the topcoat layer 14 can be selected to range from F to 3H, in which case the topcoat layer 14 has good wear resistance and can ensure the persistence of the wire pattern after drawing.

[0153] It should be noted that F is one grade in the pencil hardness scale, and the pencil hardness scale is generally divided into 13 grades in the industrial standard, decreasing from the hardest 6H to the softest 6B, in which H represents hardness and B represents blackness, 6H has the highest hardness and the lightest color, and 6B has the lowest hardness and the darkest color; and further, the pencil hardness test is a test method and measurement system for determining the hardness of the topcoat layer 14, which uses pencils of different hardness to test the hardness of the topcoat layer 14, and during the test, the pencil is drawn at an angle of 45° to the topcoat layer 14 at a speed of 1 cm / s to a length of about 1 cm, and then the damage to the topcoat layer 14 is observed to evaluate its hardness. Therefore, in general, the pencil hardness scale is an important standard for describing the hardness of the pencil lead and the hardness of the topcoat layer 14.

[0154] As an example, the material of the topcoat layer 14 can be a mixture composed of polyurethane acrylic resin, ethylene glycol butyl ether, ethyl acetate, butyl acetate, propylene glycol methyl ether acetate and photoinitiator. In the mixture, the volume percentage of polyurethane acrylic resin can range from 35% to 45%, the volume percentage of ethylene glycol butyl ether can range from 5% to 10%, the volume percentage of ethyl acetate can range from 15% to 25%, the volume percentage of butyl acetate can range from 10% to 20%, the volume percentage of propylene glycol methyl ether acetate can range from 10% to 20%, and the volume percentage of photoinitiator can range from 0.5% to 3%.

[0155] As another example, the material of the topcoat layer 14 can be a mixture composed of acrylic resin, hexaurethane resin, triurethane resin, propylene glycol methyl ether acetate, butanone, butyl acetate, initiator 184, initiator 819, acrylic co-leveling agent, and adhesion promoter. Among them, the volume percentage of the acrylic resin in the mixture can be 7%, the volume percentage of the hexaurethane resin in the mixture can be 4%, the volume percentage of the triurethane resin in the mixture can be 9%, the volume percentage of the propylene glycol methyl ether acetate in the mixture can be 20%, the volume percentage of the butanone in the mixture can be 35%, the volume percentage of the butyl acetate in the mixture can be 19.8%, the volume percentage of the initiator 184 in the mixture can be 0.5% or 1%, the volume percentage of the initiator 819 in the mixture can be 0.5% or 1%, the ratio of the acrylic co-leveling agent in the mixture can be 0.2%, and the volume percentage of the adhesion promoter in the mixture can be 3%.

[0156] In the application, the topcoat layer 14 described above can be formed by spraying or the like. Specifically, spraying can be performed by a spray gun.

[0157] Further, the UV paint can be directly sprayed on the surface corresponding to the area to be drawn of the plastic base body 3, and UV curing can be performed to directly form the topcoat layer 14.

[0158] In this process, the amount of UV used can range from 1000 mJ / cm 3 to 1200 mJ / cm 3 , the baking time can range from 8 min to 12 min, the baking temperature can range from 55°C to 65°C, the leveling time can range from 2 min to 4 min, the stirring time can range from 9 min to 11 min, and the viscosity of the UV paint can range from 8.2 S to 8.8 S. Of course, there can be other process parameters, which are not described one by one here.

[0159] Further, the first UV paint (the leveling and saturation of the first UV paint are both poor) can be sprayed on the surface corresponding to the area to be drawn of the plastic base body 3 first, then the second UV paint (the leveling and saturation of the second UV paint are both good) can be sprayed on the first UV paint, and then UV curing can be performed to form the topcoat layer 14.

[0160] It should be noted that the components of the first UV paint and the second UV paint can be the same, and the topcoat layer 14 formed finally has no layering when viewed in cross-section, which is simple and easy to implement.

[0161] The thickness d14 of the topcoat layer 14 obtained by the above different methods in the first direction (OY direction in FIGS. 9-11) can range from 15 μm to 55 μm, and for example, d14 can be 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or 55 μm, etc.

[0162] It should be noted that the OY direction refers to the direction from the outer surface to the inner surface of the plastic substrate 3. Here, the plastic substrate 3 is considered to be two-dimensional for the purpose of describing the thickness of the topcoat layer, but the plastic substrate 3 is actually three-dimensional.

[0163] If the topcoat layer 14 is too thin, the subsequent wire drawing of the topcoat layer 14 can easily penetrate the topcoat layer 14. If the coating layer is only the topcoat layer 14, the plastic substrate 3 can be damaged. If the coating layer also includes other layers, the wire drawing of the other layers can affect the wire drawing effect of the topcoat layer 14, resulting in poor wire drawing effect. However, when the topcoat layer 14 is too thick, the appearance effect is not good. In summary, the topcoat layer 14 in the above thickness range can achieve good wire drawing effect.

[0164] Referring to FIG. 9, the coating layer includes a first primer layer 10, a second primer layer 11, a plating layer 12, a color paint layer 13, and a topcoat layer 14, which are sequentially stacked on the plastic substrate 3.

[0165] The material of the first primer layer 10 can include a first thermosetting paint, and can be achieved by spray gun spraying, which can include a first thermosetting resin, a first curing agent, a first pigment, a first filler, a first solvent and a first additive, etc. The first thermosetting resin can include polyurethane resin, acrylic resin, thermosetting amino resin, epoxy resin (such as bisphenol A type epoxy resin) and silicone resin, etc. The first solvent can include ethyl acetate and ethylene glycol monobutyl ether, etc. The first pigment and the first filler can include iron red, talc powder and barite powder, etc. to provide color and enhance the physical properties of the first primer layer 10. The first additive can include accelerators, corrosion inhibitors, defoamers, dispersants, wetting agents and surfactants, etc. As an example, a thermosetting amino acid resin primer can include a thermosetting amino resin composition, paraffin, silicone oil, sodium hydroxide, ethyl acetate, water-based defoamer, water-based dispersant and deionized water. As another example, a thermosetting iron red acrylic paint includes water, ethylene glycol monobutyl ether, defoamer, surfactant, iron red, dispersant, barium metaphosphate, talc powder, barite powder, thermosetting acrylic resin, wetting agent, dibutyl phthalate, diethylene glycol butyl ether, ammonia and preservative. The thickness d10 of the first primer layer 10 along the OY direction can range from 10 μm to 30 μm. Exemplarily, d10 can be 10 μm, 16 μm, 17 μm, 18 μm, 19 μm or 30 μm, etc. The first primer layer 10 can fill the defects of the plastic substrate 3 and enhance the adhesion between the subsequently sprayed paint and the plastic substrate 3.

[0166] The material of the second primer layer 11 can include a first ultraviolet light-curable paint, and can be achieved by spray gun spraying, which can include a first resin, a first monomer, a first photoinitiator and a first photosensitive additive, etc. The first resin can include an acrylic modified epoxy resin, etc. The first monomer can include a trifunctional crosslinking monomer and a difunctional dilution monomer, etc. The thickness d11 of the second primer layer 11 along the OY direction can range from 20 μm to 30 μm. Exemplarily, d11 can be 20 μm, 22 μm, 24 μm, 26 μm, 28 μm or 30 μm, etc. The second primer layer 11 can fill the defects of the first primer layer 10 and make it easier for the subsequently sprayed paint to adhere to the surface of the first primer layer 10.

[0167] It should be noted that the second primer layer 11 needs to be relatively thick to make it flatter, so as to prevent the subsequent film layer 12 from being too thick, resulting in problems such as uneven reflection.

[0168] The material of the coating layer 12 can include indium (In) and the like. The coating layer 12 can be formed by plating In through the NCVM process. Since the target material of the NCVM is an indium wire, the original color is a thin layer of silver (e.g., less than 1 μm), so that the coating layer 12 can be very thin and achieve a shiny metallic texture. The thickness d12 of the coating layer 12 along the OY direction can be less than or equal to 1 μm. For example, d12 can be 0.1 μm, 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm or 1 μm, etc.

[0169] The material of the color paint layer 13 can include a second ultraviolet light-curable paint, which can be sprayed by a spray gun. The second ultraviolet light-curable paint can include a second resin, a second monomer, a second photoinitiator and a second photosensitive auxiliary agent, etc. The components of the second ultraviolet light-curable paint can be the same as or different from those of the first ultraviolet light-curable paint. The color paint layer 13 can be formed by selecting different materials to achieve different colors, which is helpful to achieve personalized design. The thickness d13 of the color paint layer 13 along the OY direction can range from 5 μm to 10 μm. For example, d13 can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, etc.

[0170] Referring to FIG. 10, the paint layer includes a second primer layer 11, a color paint layer 13 and a topcoat layer 14 which are sequentially stacked on the plastic substrate 3.

[0171] Different from the second primer layer 11 in FIG. 9, the material of the second primer layer 11 in FIG. 10 can include a second thermosetting paint, which can be sprayed by a spray gun. The second thermosetting paint can include a second thermosetting resin, a second curing agent, a second pigment, a second filler, a second solvent and a second auxiliary agent, etc. The components of the second thermosetting paint can be the same as or different from those of the first thermosetting paint. Since there is no coating layer as in FIG. 8, there is no problem of reflection in the subsequent process, so the second primer layer 11 can be thinner. The thickness d11 of the second primer layer 11 along the OY direction can range from 5 μm to 10 μm. For example, d11 can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, etc. The second primer layer 11 can fill the defects of the plastic substrate 3 and make the color paint layer 13 more easily adhere to the surface.

[0172] Different from the color paint layer 13 in FIG. 9, the material of the color paint layer 13 in FIG. 10 can include a third thermosetting paint. The third thermosetting paint can include a third thermosetting resin, a third curing agent, a third pigment, a third filler, a third solvent and a third auxiliary agent, etc. The components of the third thermosetting paint can be the same as or different from those of the first thermosetting paint.

[0173] Referring to Fig. 11, the paint layer includes the first primer layer 10, the second primer layer 11, the color paint layer 13 and the top coat layer 14 which are sequentially stacked on the plastic base 3.

[0174] In the first primer layer 10 in Fig. 10, the thickness d10 of the first primer layer 10 along the OY direction can range from 10 μm to 15 μm, and exemplarily, d10 can be 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm, etc.

[0175] S13. As shown in Fig. 8d, the drawing wheel 5 is rotationally connected to the fixed rod 6 and can rotate around the fixed rod 6, and the first structural member 4 is sleeved on the jig rod 7 and revolves around the drawing wheel 5 to rub the top coat layer on the surface of the first structural member 4 to draw the wire.

[0176] It should be noted that the drawing wheel 5 draws the wire of the cured top coat layer.

[0177] In addition, the first structural member 4 can be fixed, and only the drawing wheel 5 rotates around the first structural member 4 along the arrow direction of Fig. 8e to achieve the drawing. Of course, the drawing wheel 5 can also not rotate around the first structural member 4 along the arrow direction of Fig. 8e, and the actual application is specific.

[0178] In the application, the drawing wheel 5 can include a flying wing wheel, a metal wheel, etc.

[0179] The flying wing wheel can be made of composite materials such as resin, nylon and aluminum powder. The flying wing wheel is not so hard that it can not only damage the outer surface of the top coat layer to form the wire, but also can control the depth of the wire, which will not be too deep, and reduce or avoid the damage to the top coat layer. Therefore, the drawing wheel 5 is preferably a flying wing wheel.

[0180] The Vickers hardness of the flying wing wheel can range from 60 HV to 70 HV, and exemplarily, the Vickers hardness of the flying wing wheel can be 60 HV, 62 HV, 64 HV, 66 HV, 68 HV or 70 HV, etc. Thus, the flying wing wheel can continuously rub the outer surface of the top coat layer of the first structural member 4, and only slightly damage the top coat layer in the process, which ensures the stability of the wire and the top coat layer.

[0181] In addition, during the drawing process, the friction temperature between the flying wing wheel and the top coat layer is high, and the contact surface between the flying wing wheel and the top coat layer needs to be cooled by water spraying to reduce the temperature between the flying wing wheel and the top coat layer.

[0182] It should be noted that in actual application, the flying wing wheel may also have the risk of breaking the surface paint layer, but the probability of this case is very small.

[0183] S14. As shown in Figure 8e, the plastic structural part 8 is formed.

[0184] Wherein, the surface paint layer of the plastic structural part 8 has a plurality of spaced silk lines 9, the depth of the silk line 9 is less than or equal to the thickness of the surface paint layer, and all the silk lines 9 constitute a whole circle distributed on the outer surface of the surface paint layer.

[0185] The embodiment of the present application provides a preparation method of a plastic structural part, first, the plastic base material is formed into a plastic base body with a clamping line through a mold forming and injection molding, then the clamping line on the outer surface of the plastic base body is removed, then at least a surface paint layer is formed on the outer surface of the plastic base body, and then the surface paint layer is subjected to wire drawing treatment to form a plurality of macroscopically visible whole-circle continuous silk lines, the silk lines have a metal-like texture, can achieve the appearance effect of wire drawing on the surface of a metal base material, and avoid the problem of surface fiber floating, meanwhile, the surface paint layer can also cover dirt, shrinkage and particles of the plastic base body, greatly improves the product yield, increases the gloss and reliability of the product, and meets the needs of high color value and high texture of the product.

[0186] Optionally, as an implementable manner, as shown in Figure 12, in the step of sleeving the four first structural parts 4 on the jig rod 7 and making the four first structural parts 4 revolve around the wire drawing wheel 5 in the step S13, the four first structural parts 4 can be sleeved on the jig rod 7 and revolve around the wire drawing wheel 5, so that the wire drawing wheel 5 can simultaneously rub and draw the surface paint layer of the four first structural parts 4.

[0187] In application, the materials, sizes, rotation directions and rotation speeds of the four first structural parts 4 can be the same or different, and the specific application is subject to actual application.

[0188] It should be noted that the number of the first structural parts 4 can be multiple, and is not limited to four.

[0189] In addition, the thickness of the wire drawing wheel can be thickened to simultaneously draw more first structural parts 4.

[0190] The metal base material used in the related art has high hardness, so a metal wheel with high hardness is needed to draw the metal base material. Due to the characteristics of the metal wheel and the metal base material, the metal wheel can usually only process one metal base material, which results in low efficiency and high cost.

[0191] Based on the above, the preparation method of the plastic structural part provided in the embodiments of the present application can simultaneously perform wire drawing processing on multiple first structural parts by using a wire drawing wheel, and the thicker the thickness of the wire drawing wheel is, the more first structural parts can be stacked and wire drawn, which has the advantages of short processing time, low cost, high production capacity, etc.

[0192] Optionally, as one possible implementation manner, after step S13 and before step S14, the preparation method of the plastic structural part can further include:

[0193] S15. Using a brightening liquid to perform brightening processing on the wire-drawn first structural part.

[0194] In application, the brightening processing manner can include using at least one of a nano liquid, a pearl bead, a medium polishing liquid, etc. to wipe the wire-drawn first structural part.

[0195] The nano liquid is a liquid made by using nanotechnology, and its main components include nanoscale oxide materials and other high-molecular polymer materials. By covalent bonding of molecular bonds, a nanoscale protective layer with special protection function and stable structure is formed on the surface of the object. This protective layer can not only enhance the surface hardness, wear resistance and chemical corrosion resistance of the object, but also significantly improve the gloss and transparency of the object, thereby achieving the effect of brightening.

[0196] The pearl bead is a water-based maintenance and polishing agent, and its main components include petroleum alkanes, silicone oil and distilled water. It can effectively remove nanoscale defects such as oil stains, wine stains and coffee stains, thereby achieving the effect of brightening.

[0197] The medium polishing liquid is a water-soluble polishing agent without any sulfur, phosphorus and chlorine additives. The medium polishing liquid has good oil stain removal, cleaning and lightening properties, and can make the product have a metallic texture.

[0198] It should be noted that the brightening liquid does not react with the wire-drawn first structural part, but increases the brightness through physical action.

[0199] After wire drawing of the first structural part, a small amount of haze and blackening defects will inevitably appear on the outer surface of the topcoat layer. Based on this, the preparation method of the plastic structural part provided in the embodiments of the present application can wipe the outer surface of the topcoat layer by using the brightening liquid, which can effectively remove dirt on the outer surface of the topcoat layer, thereby brightening and smoothing the appearance of the product, greatly improving the appearance of the plastic structural part, and making it have better metallic texture and high light effect.

[0200] Please refer to FIGS. 13 to 15 for a detailed introduction to the wire pattern on the outer surface of the plastic structural part prepared by the wire drawing process provided in the embodiments of the present application.

[0201] As shown in FIG. 13, the topcoat layer 14 includes six filigree lines 9, which are distributed in a whole circle of the topcoat layer 14 and have a spacing between two adjacent filigree lines 9, and the extension directions of the six filigree lines 9 are the same.

[0202] It should be noted that the number of the filigree lines 9 is not limited to six, and the extension directions of the filigree lines 9 can be partially the same or totally different, which is subject to actual application.

[0203] On the basis of the above, FIG. 14 shows a distribution diagram of the filigree lines 9 of the first surface 141 of the topcoat layer in FIG. 13. As shown in FIG. 14, the spacing w1 and w2 between two adjacent filigree lines 9 can range from 4 μm to 7 μm, and exemplarily, w1 and w2 can be 4 μm, 5 μm, 6 μm or 7 μm, etc. Further, the number of the filigree lines 9 within 20 μm can range from 3 to 6.

[0204] It should be noted that w1 and w2 can be the same or different, which is subject to actual application.

[0205] Referring to FIG. 14 again, the maximum surface width k of each filigree line 9 along the OX direction can range from 1 μm to 3 μm, and exemplarily, k can be 1 μm, 2 μm or 3 μm, etc. It should be noted that the OX direction is perpendicular to the OY direction.

[0206] On the basis of the above, FIG. 15 shows a sectional view of the topcoat layer 14 in FIG. 13. As shown in FIG. 15, the depth s of the filigree line 9 can range from 10 μm to 55 μm, and typically, the range of s can be selected from 10 μm to 30 μm. Wherein, referring to FIG. 13 and FIG. 15, the filigree line extends from the outer surface to the inner surface of the topcoat layer to form a long strip-shaped opening structure with a certain depth.

[0207] Specifically, when the thickness of the topcoat layer along the OY direction is 15 μm and the depth s of the filigree line is 10 μm, the filigree line penetrates the topcoat layer; when the thickness of the topcoat layer along the OY direction is 15 μm and the depth s of the filigree line is 15 μm, the filigree line penetrates the whole topcoat layer, which is not specifically limited here.

[0208] It should be noted that the greater the stroke of the flying wing wheel pressed into the topcoat layer, the higher the speed and the more the number of laps, and the deeper the depth of the filigree line.

[0209] The specifications of the filigree line, such as the spacing, density, depth and extension direction, etc. can be adjusted according to the type of the paint of the topcoat layer, the thickness of the topcoat layer, etc. Exemplarily, a plurality of filigree lines can be distributed in vertical lines, horizontal lines or random lines, wherein the random lines can be at least partially different in spacing, density, depth and extension direction, etc., but as long as it is macroscopically a whole circle of continuous filigree lines.

[0210] In addition, the above-mentioned silk lines, when viewed under a microscope, can be discontinuous, but the naked eye cannot see the discontinuity under a macroscopic view.

[0211] The plastic structural member provided by the embodiment of the present application has a macroscopically continuous silk line on the outer surface of the surface paint layer, and the silk line has various textures, which enriches the appearance of the plastic structural member.

[0212] Optionally, as an implementable manner, as shown in FIG. 16, a fingerprint-proof layer 15 is further formed on the side of the surface paint layer 14 of the plastic structural member away from the plastic base 3.

[0213] The plastic structural member provided by the embodiment of the present application can enhance the wear resistance of the plastic structural member through the fingerprint-proof layer, especially when the user rubs in the palm direction, the anti-friction ability is stronger, which effectively slows down the failure speed and time of the plastic structural member, does not affect the display, and effectively improves the performance.

[0214] The above only introduces the content related to the invention points, and the remaining content can be obtained by referring to the related art, which will not be described in detail here.

[0215] It should be understood that the above is only to help those skilled in the art better understand the embodiments of the present application, and is not intended to limit the scope of the embodiments of the present application. Those skilled in the art can obviously make various equivalent modifications or changes according to the above examples. Or the combination of any two or more embodiments. Such modifications, changes or combinations also fall within the scope of the embodiments of the present application.

[0216] It should also be understood that the above description of the embodiments of the present application focuses on the differences between the various embodiments, and the same or similar parts not mentioned can be mutually referred to, and for the sake of brevity, will not be described here.

[0217] It should also be understood that the division of the modes, cases, categories and embodiments in the embodiments of the present application is only for the convenience of description, and should not be considered as a special limitation. The features in various modes, categories, cases and embodiments can be combined without contradiction.

[0218] It should also be understood that in various embodiments of the present application, the terms and / or descriptions of different embodiments are consistent and can be mutually referred to if there is no special description and logical conflict. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0219] It should be pointed out that the above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any change or replacement within the technical scope disclosed by the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A plastic structural member, characterized by, The present application relates to a plastic structure, comprising: a plastic base; a paint layer, which is arranged on the outer surface of the plastic base, the paint layer comprising at least a topcoat layer, the topcoat layer forming the appearance surface of the plastic structure; wherein the topcoat layer has a plurality of spaced filigree lines, the depth of the filigree lines being less than or equal to the thickness of the topcoat layer, and all the filigree lines are distributed in a whole circle on the outer surface of the topcoat layer.

2. The plastic structural member of claim 1, wherein The material of the topcoat layer comprises polyurethane acrylic resin, ethyl acetate and photoinitiator; and / or, The pencil hardness of the topcoat layer ranges from HB to 4H; and / or, The thickness of the topcoat layer ranges from 15 μm to 55 μm.

3. The plastic structural member according to claim 1 or 2, wherein The spacing between adjacent two filigree lines ranges from 4 μm to 7 μm; and / or, The maximum surface width of each filigree line ranges from 1 μm to 3 μm; and / or, The depth of each filigree line ranges from 10 μm to 55 μm.

4. The plastic structural member of claim 3, wherein The depth of the filigree lines is less than the thickness of the topcoat layer, and the depth of the filigree lines ranges from 10 μm to 50 μm.

5. The plastic structural member according to any one of claims 1 to 4, wherein The paint layer further comprises a first primer layer, a second primer layer, a plating layer and a color paint layer, the first primer layer is arranged between the plastic base and the second primer layer, the second primer layer is arranged between the first primer layer and the plating layer, the plating layer is arranged between the second primer layer and the color paint layer, and the color paint layer is arranged between the plating layer and the topcoat layer; The material of the first primer layer comprises a first thermosetting paint, the first thermosetting paint comprises a first thermosetting resin, a first curing agent, a first pigment, a first filler, a first solvent and a first additive, and the thickness of the first primer layer ranges from 10 μm to 30 μm; The material of the second primer layer comprises a first ultraviolet curing paint, the first ultraviolet curing paint comprises a first resin, a first monomer, a first photoinitiator and a first photosensitive additive, and the thickness of the second primer layer ranges from 20 μm to 30 μm; The material of the plating layer comprises indium, and the thickness of the plating layer is less than or equal to 1 μm; The material of the color paint layer comprises a second ultraviolet curing paint, the second ultraviolet curing paint comprises a second resin, a second monomer, a second photoinitiator and a second photosensitive additive, and the thickness of the color paint layer ranges from 5 μm to 10 μm.

6. The plastic structural member according to any one of claims 1 to 4, wherein The paint layer further comprises a second primer layer and a color paint layer, the second primer layer is arranged between the plastic base and the color paint layer, and the color paint layer is arranged between the second primer layer and the topcoat layer; The material of the second primer layer comprises a second thermosetting paint, the second thermosetting paint can comprise a second thermosetting resin, a second curing agent, a second pigment, a second filler, a second solvent and a second additive, and the thickness of the second primer layer ranges from 5 μm to 10 μm; The material of the color paint layer comprises a third thermosetting paint, the third thermosetting paint can comprise a third thermosetting resin, a third curing agent, a third pigment, a third filler, a third solvent and a third additive, and the thickness of the color paint layer ranges from 5 μm to 10 μm.

7. The plastic structural member according to any one of claims 1 to 4, wherein The paint layer further comprises a first primer layer, a second primer layer and a color paint layer, the first primer layer is arranged between the plastic base and the second primer layer, the second primer layer is arranged between the first primer layer and the color paint layer, and the color paint layer is arranged between the second primer layer and the topcoat layer; The material of the first primer layer comprises a first thermosetting paint, and the first thermosetting paint comprises a first thermosetting resin, a first curing agent, a first pigment, a first filler, a first solvent and a first additive, and the thickness of the first primer layer ranges from 10 μm to 15 μm; The material of the second primer layer comprises a first ultraviolet curing paint, and the first ultraviolet curing paint comprises a first resin, a first monomer, a first photoinitiator and a first photosensitive additive, and the thickness of the second primer layer ranges from 20 μm to 30 μm; The material of the color paint layer comprises a second ultraviolet curing paint, and the second ultraviolet curing paint comprises a second resin, a second monomer, a second photoinitiator and a second photosensitive additive, and the thickness of the color paint layer ranges from 5 μm to 10 μm.

8. The plastic structural member according to any one of claims 1 to 7, wherein, The material of the plastic base comprises at least one of polycarbonate, polyamide, polyethyleneimine, polycarbonate and glass fiber, polyamide and glass fiber, and polyethyleneimine and glass fiber. And / or, The Vickers hardness of the plastic base ranges from 60 HV to 90 HV.

9. The plastic structural member according to any one of claims 1 to 8, wherein, The plastic base is an injection molded part, and the outer surface of the plastic base is free of wire clamping.

10. The plastic structural member according to any one of claims 1 to 9, wherein, The plastic structural part comprises at least one of a notebook computer shell, a mobile phone middle frame, a tablet computer middle frame and a battery cover.

11. An electronic device, comprising: The plastic structural part comprises at least one of a notebook computer shell, a mobile phone middle frame, a tablet computer middle frame and a battery cover.

12. A method of making a plastic structural member, comprising: Forming a plastic base; wherein the outer surface of the plastic base is free of wire clamping; Forming a paint layer on the outer surface of the plastic base in the area to be drawn; wherein the paint layer comprises at least a topcoat layer; Drawing the topcoat layer to form the plastic structural part; wherein the topcoat layer has a plurality of spaced silk lines, the depth of the silk lines is less than or equal to the thickness of the topcoat layer, all silk lines are distributed in a whole circle on the outer surface of the topcoat layer, and the topcoat layer forms the appearance surface of the plastic structural part. The forming of the plastic base comprises:

13. The method of claim 12, wherein the step of forming the plastic structure is performed by injection molding. Using a mold to form a first structural part by molding and injection molding of a plastic raw material; wherein the outer surface of the first structural part has wire clamping; Removing the wire clamping to form the plastic base. The method of removing the wire clamping comprises polishing or computer numerical control processing.

14. The method of claim 13, wherein the step of forming the plastic structure is performed by injection molding. The drawing of the topcoat layer to form the plastic structural part comprises:

15. The method of claim 12 to 14, wherein Using a drawing wheel to draw the topcoat layer, and using a brightening liquid to wipe the outer surface of the topcoat layer to form the plastic structural part. The drawing wheel comprises a flying wing wheel; 16. The method of claim 15, wherein the step of forming the plastic structure is performed by injection molding. The material of the flying wing wheel comprises resin, nylon and aluminum powder; And / or, The Vickers hardness of the flying wing wheel ranges from 60 HV to 70 HV. ​

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