CN114472112A

CN114472112A - Electronic equipment, shell and preparation method thereof

Info

Publication number: CN114472112A
Application number: CN202210103088.4A
Authority: CN
Inventors: 宋泽凯; 徐幸河; 吴亮
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2022-01-27
Filing date: 2022-01-27
Publication date: 2022-05-13
Anticipated expiration: 2042-01-27
Also published as: CN114472112B

Abstract

The application provides an electronic device, a shell and a preparation method thereof; the preparation method comprises the following steps: providing a substrate; spraying and forming a primer layer on the substrate; wherein the primer layer comprises sand grain powder; spraying and forming a middle paint layer on the primer layer; and spraying the intermediate paint layer to form a finish paint layer. According to the preparation method of the shell, the shell with the glittering point effect can be obtained by doping the sand grain powder into the primer, and the appearance expressive force of the product can be improved; the method has simple process and excellent adhesion reliability between the coatings.

Description

Electronic equipment, shell and preparation method thereof

Technical Field

The invention relates to the technical field of electronic equipment shell preparation processes, in particular to electronic equipment, a shell and a preparation method thereof.

Background

The common material of plastic decoration in current metal cell-phone is PC. In order to solve the problems of poor surface texture and poor scratch resistance of plastics, a technical scheme of NCVM (Non Conductive vacuum metallization, discontinuous coating technology or Non-Conductive electroplating technology) + spraying is generally adopted, and a high-gloss or matte coating is sprayed on the surface by adopting a process of common spraying and NCVM to realize a surface effect.

Disclosure of Invention

A first aspect of an embodiment of the present application provides a method for manufacturing a housing, where the method includes:

providing a substrate;

spraying and forming a primer layer on the substrate; wherein the primer layer comprises sand grain powder;

spraying and forming a middle paint layer on the primer layer;

and spraying the intermediate paint layer to form a finish paint layer.

In a second aspect, embodiments of the present application provide a housing, which includes a substrate, and a primer layer, a middle paint layer, and a finish paint layer, which are stacked on the substrate at one time; wherein, the priming paint layer comprises sand grain powder.

In addition, this application embodiment provides an electronic equipment again, electronic equipment includes display screen module, control circuit board and the casing in the above-mentioned embodiment, the display screen module with the casing cooperation forms the accommodation space, control circuit board locates the accommodation space, and with display screen module electric connection.

According to the preparation method of the shell, the shell with the glittering point effect can be obtained by doping the sand grain powder into the primer, and the appearance expressive force of the product can be improved; the method has simple process and excellent adhesion reliability between the coatings.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic flow chart of an embodiment of a method of making the shell of the present application;

FIG. 2 is a schematic flow chart of forming a primer layer on a substrate;

FIG. 3 is a schematic cross-sectional view of the structure after formation of a primer layer on the substrate;

FIG. 4 is a schematic cross-sectional view of the structure after formation of the intermediate paint layer;

FIG. 5 is a schematic cross-sectional view of the structure after formation of the topcoat layer;

FIG. 6 is a schematic flow chart of another embodiment of a method of making the shell of the present application;

FIG. 7 is a schematic cross-sectional view of the structure after formation of a primer layer;

FIG. 8 is a schematic cross-sectional view of the housing construction after the application has been finished;

FIG. 9 is a schematic structural diagram of an embodiment of an electronic device of the present application;

FIG. 10 is a schematic sectional view of the electronic device at A-A in the embodiment of FIG. 9;

fig. 11 is a block diagram illustrating a structural composition of an embodiment of an electronic device according to the present application.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be noted that the following examples are only illustrative of the present invention, and do not limit the scope of the present invention. Likewise, the following examples are only some but not all examples of the present invention, and all other examples obtained by those skilled in the art without any inventive step are within the scope of the present invention.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

As used herein, an "electronic device" (or simply "terminal") includes, but is not limited to, an apparatus that is configured to receive/transmit communication signals via a wireline connection, such as via a Public Switched Telephone Network (PSTN), a Digital Subscriber Line (DSL), a digital cable, a direct cable connection, and/or another data connection/network, and/or via a wireless interface (e.g., for a cellular network, a Wireless Local Area Network (WLAN), a digital television network such as a DVB-H network, a satellite network, an AM-FM broadcast transmitter, and/or another communication terminal). A communication terminal arranged to communicate over a wireless interface may be referred to as a "wireless communication terminal", "wireless terminal" or "mobile terminal". Examples of mobile terminals include, but are not limited to, satellite or cellular telephones; a Personal Communications System (PCS) terminal that may combine a cellular radiotelephone with data processing, facsimile and data communications capabilities; PDAs that may include radiotelephones, pagers, internet/intranet access, Web browsers, notepads, calendars, and/or Global Positioning System (GPS) receivers; and conventional laptop and/or palmtop receivers or other electronic devices that include a radiotelephone transceiver. A cellular phone is an electronic device equipped with a cellular communication module.

Referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of a method for manufacturing a housing according to the present application; the shell obtained by the preparation method in the application can be used in electronic equipment, and the electronic equipment can include a mobile phone, a tablet computer, a notebook computer, wearable equipment, and the like. Specifically, the method for manufacturing the housing in this embodiment includes, but is not limited to, the following steps. It should be noted that the terms "comprises" and "comprising," and any variations thereof, in the embodiments of the present application, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements but may alternatively include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In step S100, a substrate is provided.

In this step, the substrate may be made of PET (Polyethylene terephthalate, abbreviated as PET or PEIT, commonly called polyester resin, a polycondensate of terephthalic acid and ethylene glycol), PMMA (poly (methyl methacrylate), abbreviated as PMMA), also called acryl, Acrylic or organic glass, PC (Polycarbonate, Polycarbonate is a high molecular polymer containing a carbonate group in a molecular chain), PI (Polyimide) ABS (terpolymer) of three monomers of acrylonitrile (a), butadiene (B), and styrene (S), and the like. Further material types for the substrate are not listed and detailed here within the understanding of the person skilled in the art.

Selecting a proper substrate, generally selecting PC (PC material has high strength, excellent fatigue resistance, weather resistance and good dimensional stability, is widely applied in the electronic industry), wiping the material by using dust-free cloth before spraying, and performing electrostatic dust removal.

Referring to fig. 1, the method for manufacturing the housing of the present embodiment further includes:

step S200, spraying and forming a primer layer on the substrate.

Referring to fig. 2 and fig. 3 together, fig. 2 is a schematic flow chart of forming a primer layer on a substrate, fig. 3 is a schematic cross-sectional view of a structure after forming the primer layer on the substrate, and optionally, step S200 (spraying the primer layer on the substrate) specifically includes step 210, in which a first primer layer is sprayed on the substrate.

Preparing a coating: all the coatings are stirred for 3-5min by a stirrer at the rotating speed of 400-600r/min before spraying so as to ensure that all components of the coatings can be fully and uniformly mixed, the viscosity is measured by an NK-2 type viscosity cup, the viscosity of each coating is kept at 8-10s (the viscosity is too high, the spraying construction is difficult, the coating cannot be effectively atomized, the viscosity is too low, the film thickness is thin after spraying), and after the measurement, each coating is filtered by 300-mesh nylon gauze so as to remove impurities in the coating.

Wherein (the coating of) the first primer layer 121 includes a first film-forming resin, a first monomer, a first initiator, and a first solvent; alternatively, the first film-forming resin may include urethane acrylate, and specifically may be 2-functional (refer to 2 functional groups, the same applies hereinafter) urethane acrylate; the first monomer may include trimethylolpropane triacrylate (TMPTA) and 1, 6-hexanediol diacrylate (HDDA); the first initiator may include diphenyl (2,4, 6-Trimethylbenzoyl) Phosphine Oxide (TPO); the first solvent comprises at least one of ethylene glycol monobutyl ether, isopropanol, butanone, ethyl acetate and butyl acetate.

Compressed air is selected as spraying gas of the first primer layer 121, the spraying pressure is 0.2-0.4Mpa (too low, the coating cannot be sprayed out smoothly, the spraying pressure is too high, the material product is easy to shake, and the spraying is poor), the spraying atomization is controlled to be 1.5-1.7 (too small, the material film is uneven, too large, the material film is too low), the spraying room temperature is 20-30 ℃, the spraying room humidity is 60-80% RH, the spraying film thickness is about 20-30um (the film thickness is too thin, the excellent mirror leveling effect cannot be formed, the interlayer adhesion is affected by too thick spraying), the coating needs to be leveled in an oven of 60-70 ℃ for 8-10min after the spraying is finished to ensure that the solvent is completely volatilized, and after the leveling is finished, the coating is cured for 1-2min in an UV room with the UV lamp strength of 700 and 1000mj/mW2 to ensure that the coating is completely cured, the adhesive force performance is ensured.

Continuing with fig. 2, step S200 (spray forming a primer layer on the substrate) further includes step 220, spray forming a second primer layer on the first primer layer.

Optionally, the primer layer 120 in the embodiment of the present application includes a first primer layer 121 and a second primer layer 122, and in some other embodiments, may further include a structural form of a multi-layer primer layer, which is not listed and described in detail herein.

Optionally, second primer layer 122 in this embodiment includes a second film-forming resin, a second monomer, a second initiator, a second solvent, and a gritty powder; wherein the second film-forming resin comprises urethane acrylate, and specifically can be 2-functional urethane acrylate; the second monomer comprises trimethylolpropane triacrylate (TMPTA) and 1, 6-hexanediol diacrylate (HDDA); the second initiator comprises 2-hydroxy-2-methyl-1-phenyl-1-acetone (1173 chemical name of the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-acetone, called HMPP for short, and the structural formula is C6H5COC (CH3)2OH, English name is photoinitiator 1173), and the second solvent comprises toluene and acetophenone; the sand grain powder is organic silicon modified polymethyl methacrylate (organic silicon modified PMMA). Referring to the table below, the table below shows the refractive index contrast of the gritty powder to the conventional material.

Type (B)	Organic silicon modified PMMA	PMMA	Photocurable coatings
				Refractive index	1.65	1.5	1.45-1.5

Compared with common PMMA and photocureable coatings, the PMMA sand grain powder modified by organic silicon has higher refractive index, and can generate stronger scattering effect after light incidence, thereby showing appearance effect which is completely different from common highlight.

Adding the sand grain powder into the second primer layer coating according to the proportion of 2-5%, and stirring for 3-5min at the rotating speed of 400-600r/min by using a stirrer; the spraying gas is compressed air, the spraying pressure is 0.3-0.5Mpa (the spraying pressure is too low, sand grain powder cannot be smoothly and uniformly sprayed, the spraying pressure is too high, the shaking of a material product is easily caused, and the spraying is poor), the spraying atomization is controlled to be 1.5-1.7 (the atomization is too small, the thickness of the material film is uneven, the atomization is too large, the thickness of the material film is too low), the temperature of a spraying room is 20-30 ℃, the humidity of the spraying room is 60-80% RH, the thickness of the spraying film is about 6-10um (the thickness of the film is too thin, the defect of the material cannot be covered, the thickness of the film is too thick, effective interlayer adhesion cannot be formed), the spraying is leveled for 8-10min in an oven at the temperature of 60-70 ℃ after the spraying is finished, the solvent is completely volatilized, after the leveling is finished, the coating is cured for 1-2min in an UV chamber with the intensity of 700 mj/mW2, so as to ensure the complete curing of the coating, the adhesive force performance is ensured.

Referring to fig. 1, the method for manufacturing the housing in this embodiment further includes a step S300 of spraying a middle paint layer on the primer layer.

Referring to fig. 4, fig. 4 is a schematic cross-sectional view of a structure after forming the intermediate paint layer, in the present embodiment, the intermediate paint layer 130 is formed on the second primer layer 122.

Optionally, the intermediate paint layer (paint) in this embodiment includes a third film forming resin, a third initiator, a third solvent, and a color paste; wherein the third film-forming resin comprises a solvent-based acrylic resin; the third initiator comprises phenyl bis (2,4, 6-trimethylbenzoyl) phosphine oxide (819 for short, chemical formula C26H27O 3P); the third solvent comprises one or more of methyl ethyl butyl ketone, ethyl acetate and butyl acetate; the color paste comprises carbon powder, titanium dioxide and the like.

Adding color paste into the intermediate paint according to the proportion of 1-5 percent, stirring for 3-5min at the rotating speed of 400-, to ensure that the solvent is completely volatilized, and curing for 1-2min in a UV chamber with the intensity of the UV lamp of 700-1000mj/mW2 after leveling is finished so as to ensure that the coating is completely cured and the adhesive force performance is ensured. It should be noted that the terms "first", "second" and "third" in the embodiments of the present application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

Referring to fig. 1, the method for manufacturing the housing of the present embodiment further includes a step S400 of spraying a finishing paint layer on the intermediate paint layer.

Referring to fig. 5, fig. 5 is a cross-sectional view of the structure after the topcoat layer is formed. Alternatively, the topcoat layer 140 (coating) in this embodiment includes a fourth film-forming resin, a fourth monomer, a fourth initiator, and a fourth solvent; wherein the fourth film-forming resin comprises urethane acrylate, and specifically can be 9-functional urethane acrylate; the fourth monomer comprises poly dipentaerythritol hexaacrylate (DPHA for short); the fourth initiator comprises diphenyl (2,4, 6-trimethylbenzoyl) phosphine oxide (TPO for short); the fourth solvent comprises at least one of ethylene glycol monobutyl ether, isopropanol, ethyl methyl ethyl acetate and butyl acetate.

Compressed air is selected as spraying gas of the finish paint layer 140, the spraying pressure is 0.2-0.4Mpa (too low, the paint can not be sprayed out smoothly; too high, the material product is easy to shake, the spraying is poor), the spraying atomization is controlled to be 1.5-1.7 (too small, the material film is uneven, too large, the material film is low), the spraying room temperature is 20-30 ℃, the spraying room humidity is 60-80% RH, the spraying film thickness is about 20-30um (the film thickness is too thin, the finish paint can not form effective protection; the spraying thickness affects the adhesive force), the leveling is carried out in an oven at 60-70 ℃ for 8-10min after the spraying is finished, the solvent is ensured to be volatilized completely, after the leveling is finished, the curing is carried out for 1-2min in an UV chamber with the UV lamp strength of 700 mj/mW2, so as to ensure the paint to be completely cured, the adhesive force performance is ensured. The conventional process can only rely on adjusting the topcoat to achieve visual appearance, which in the examples of this application is achieved by adjusting the primer.

In the preparation method of the housing in the embodiment, the first primer layer 121 mainly provides a mirror leveling effect, and a high-gloss monomer and a high-gloss resin are selected; the second primer layer 122 mainly provides the plating property of the evaporation plating, so that urethane acrylate with better plating property is selected; the intermediate paint layer 130 is formed by solvent type polyurethane acrylate and a coating layer with excellent adhesion performance; the finish paint layer 140 is made of 9-functional polyurethane acrylate with high functionality, and the cured finish paint layer is high in crosslinking density, so that the film layer is guaranteed to have excellent wear resistance.

According to the preparation method of the shell, the shell with the glittering point effect can be obtained by doping the sand grain powder into the primer, and the appearance expressive force of the product can be improved; the method has simple process and excellent adhesion reliability between coatings.

Referring to fig. 6, fig. 6 is a schematic flow chart of another embodiment of a method for manufacturing a housing according to the present application; the method for preparing the shell in this embodiment includes, but is not limited to, the following steps.

In step S100, a substrate is provided.

The material of the substrate may be as described in the foregoing embodiments, and is not described herein again.

Step S500, a treating agent layer is formed on the substrate by spraying.

Alternatively, the treatment agent layer (coating material) in the present embodiment includes a fifth film-forming resin, a fifth monomer, a fifth initiator, and a fifth solvent; wherein, the fifth film forming resin comprises urethane acrylate, and can be 6-functional urethane acrylate. The fifth monomer may include isopropyl acrylate (IBOA) and trimethylolpropane triacrylate (TMPTA); the fifth initiator may include diphenyl (2,4, 6-trimethylbenzoyl) phosphine oxide (TPO for short); the fifth solvent may include any one or a mixture of n-butanol, acetone, ethyl acetate, and ethyl acetate.

Compressed air is selected as spraying gas of the treating agent layer, the spraying air pressure is 0.2-0.4Mpa (the spraying air pressure is too low, the coating cannot be sprayed out smoothly, the spraying pressure is too high, the material product is easy to shake, and the spraying is poor), the spraying atomization is controlled to be 1.5-1.7 (the atomization is too small, the material film thickness is uneven, the atomization is too large, the material film thickness is low), the spraying room temperature is 20-30 ℃, the spraying room humidity is 60-80% RH, the spraying film thickness is about 3-6um (the film thickness is too thin, the material defect cannot be covered, the film thickness is too thick, effective interlayer adhesion cannot be formed), and after the spraying is finished, the spraying needs to be leveled in an oven at 60-70 ℃ for 5-8min to ensure that the solvent is volatilized completely. It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present application are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.

Referring to fig. 6, the method for manufacturing the housing according to the embodiment of the present disclosure further includes:

step S600, spraying and forming a primer layer on the treating agent layer.

The primer layer in this embodiment may also be in a structural form including a first primer layer and a second primer layer, please refer to fig. 7, and fig. 7 is a schematic cross-sectional view of a structure after the primer layer is formed, in which the first primer layer 121 is formed on the treating agent layer 150. For the specific material of the primer layer and the spraying parameters, reference may be made to the description of the foregoing embodiments.

and step S700, forming a metal indium layer on the second primer layer by using a vacuum coating mode.

And putting the product sprayed with the second primer layer into a vacuum evaporation electroplating furnace, wherein the plating material uses metal indium (ensuring that the surface of the product after film plating has excellent highlight effect and metal texture), the vacuum value is controlled at (5-7) × 10-2Pa, and the vacuum plating time is 30-40min (ensuring that evaporated indium atoms can be uniformly and stably deposited on the surface of the product).

Please refer to fig. 6 and 8, fig. 8 is a schematic cross-sectional view of the housing after the spraying process is completed. The preparation method of the shell in the embodiment of the application further comprises the following steps:

and step S800, spraying and forming a middle paint layer on the metal indium layer.

And S400, spraying and forming a finish paint layer on the intermediate paint layer.

For the spraying parameters of the intermediate paint layer 130 and the top paint layer 140, reference is made to the description of the previous embodiments. Wherein, the intermediate paint layer 130 is formed on the indium metal layer 160.

Referring to the table below, the following table shows the coating compositions of one embodiment of the housing of the present application.

Different from the previous embodiment, in the shell preparation method in the embodiment, the treatment agent layer is formed on the substrate, so that defects of the material can be covered, interlayer adhesion between the plating material and the primer is provided, and a monomer with strong erosive power is selected, so that the material can be better bitten, the contact area is increased, and the adhesion is improved; in addition, by forming the metallic indium layer between the primer layer and the topcoat layer, a case having excellent highlight effect and metallic feeling can be formed.

Further, an electronic device is provided in an embodiment of the present application, please refer to fig. 9 and fig. 10 together, fig. 9 is a schematic structural diagram of an embodiment of the electronic device of the present application, fig. 10 is a schematic structural sectional view of the electronic device at a position a-a in the embodiment of fig. 9, and the electronic device in the embodiment may include a display module 30, a housing 10, and a control circuit board 20. The housing 10 may be prepared by the preparation method in the foregoing embodiment.

Optionally, the display screen module 30 and the housing 10 cooperate to form an accommodating space 1000, the control circuit board 20 is disposed in the accommodating space 1000, the control circuit board 20 is electrically connected to the display screen module 30, and the control circuit board 20 is configured to control the display screen module 30. The detailed technical features of other parts of the electronic device are within the understanding of those skilled in the art, and are not described herein.

Referring to fig. 11, fig. 11 is a block diagram illustrating a structural composition of an embodiment of an electronic device according to the present application, where the electronic device may be a mobile phone, a tablet computer, a notebook computer, a wearable device, and the like, and the embodiment illustrates a mobile phone as an example. The electronic device may include an RF circuit 910, a memory 920, an input unit 930, a display unit 940 (which may be the display screen module 30 in the above embodiments), a sensor 950, an audio circuit 960, a wifi module 970, a processor 980 (which may be the control circuit board 20 in the above embodiments), a power supply 990, and the like. Wherein the RF circuit 910, the memory 920, the input unit 930, the display unit 940, the sensor 950, the audio circuit 960, and the wifi module 970 are respectively connected with the processor 980; power supply 990 is used to provide power to the entire electronic device.

Specifically, the RF circuit 910 is used for transmitting and receiving signals; the memory 920 is used for storing data instruction information; the input unit 930 is used for inputting information, and may specifically include a touch panel 931 and other input devices 932 such as operation keys; the display unit 940 may include a display panel 941; the sensor 950 includes an infrared sensor, a laser sensor, etc. for detecting a user approach signal, a distance signal, etc.; a speaker 961 and a microphone 962 are connected to the processor 980 through the audio circuit 960 for emitting and receiving sound signals; the wifi module 970 is used for receiving and transmitting wifi signals, and the processor 980 is used for processing data information of the electronic device. For specific structural features of the electronic device, please refer to the related description of the above embodiments, and detailed descriptions thereof will not be provided herein.

In the electronic equipment in the embodiment, the shell of the electronic equipment can obtain the shell with the flashing point effect by doping the sand grain powder into the primer, so that the appearance expressive force of the product can be improved; the method has simple process and excellent adhesion reliability between the coatings.

The above description is only a part of the embodiments of the present invention, and not intended to limit the scope of the present invention, and all equivalent devices or equivalent processes performed by the present invention through the contents of the specification and the drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A method of making a housing, the method comprising:

providing a substrate;

spraying and forming a middle paint layer on the primer layer;

and spraying the intermediate paint layer to form a finish paint layer.

2. The method according to claim 1, wherein the step of spray forming a primer layer on the substrate specifically comprises: spraying and forming a first primer layer on the substrate, and spraying and forming a second primer layer on the first primer layer, wherein the second primer layer comprises sand grain powder.

3. The method of claim 2, wherein the step of spray forming a first primer layer on the substrate further comprises: spraying and forming a treating agent layer on the substrate; wherein the first primer layer is formed on the treatment agent layer.

4. A production method according to claim 2, wherein the first primer layer comprises a first film-forming resin, a first monomer, a first initiator, and a first solvent; wherein the first film-forming resin comprises urethane acrylate; the first monomer comprises trimethylolpropane triacrylate and 1, 6-hexanediol diacrylate; the first initiator comprises diphenyl (2,4, 6-trimethylbenzoyl) phosphine oxide; the first solvent comprises at least one of ethylene glycol monobutyl ether, isopropanol, butanone, ethyl acetate and butyl acetate.

5. The production method according to claim 4, wherein the second primer layer includes a second film-forming resin, a second monomer, a second initiator, a second solvent, and a graining powder; wherein the second film-forming resin comprises urethane acrylate; the second monomer comprises trimethylolpropane triacrylate and 1, 6-hexanediol diacrylate; the second initiator comprises 2-hydroxy-2-methyl-1-phenyl-1-acetone, and the second solvent comprises toluene and acetophenone; the sand grain powder is organic silicon modified polymethyl methacrylate.

6. The preparation method according to claim 1, wherein the intermediate paint layer comprises a third film-forming resin, a third initiator, a third solvent and a color paste; wherein the third film-forming resin comprises a solvent-based acrylic resin; the third initiator comprises phenyl bis (2,4, 6-trimethylbenzoyl) phosphine oxide; the third solvent comprises methyl ethyl butyl ketone, ethyl acetate and butyl acetate; the color paste comprises carbon powder and titanium dioxide.

7. The method of claim 1, wherein the topcoat layer comprises a fourth film-forming resin, a fourth monomer, a fourth initiator, and a fourth solvent; wherein the fourth film-forming resin comprises urethane acrylate; the fourth monomer comprises polydipentaerythritol hexaacrylate; the fourth initiator comprises diphenyl (2,4, 6-trimethylbenzoyl) phosphine oxide; the fourth solvent comprises at least one of ethylene glycol monobutyl ether, isopropanol, ethyl methyl ethyl acetate and butyl acetate.

8. The method of claim 3, wherein the step of spray forming a midcoat layer on the primer layer further comprises: forming a metal indium layer on the second primer layer by using a vacuum coating mode; the intermediate paint layer is formed on the metal indium layer.

9. A shell is characterized by comprising a substrate, a primer layer, a middle paint layer and a finish paint layer, wherein the primer layer, the middle paint layer and the finish paint layer are laminated on the substrate at one time; wherein, the priming paint layer comprises sand grain powder.

10. An electronic device, comprising a display module, a control circuit board and the housing of claim 9, wherein the display module and the housing cooperate to form an accommodating space, and the control circuit board is disposed in the accommodating space and electrically connected to the display module.