Composite material plate with patterns, preparation method of composite material plate and electronic product shell

Abstract

The invention provides a composite material plate with patterns, a preparation method of the composite material plate and an electronic product shell. The preparation method comprises the steps that a release film, a glass fiber prepreg and a heat transfer printing film are sequentially stacked and integrally formed in a hot pressing mode; and after hot pressing is finished, removing the release film, and meanwhile, removing the base material layer of the heat transfer printing film to obtain the composite material plate with the patterns. According to the integrated forming process of the composite material substrate and the heat transfer printing membrane, namely the preparation method of the composite material plate with the patterns, provided by the invention, the glass fiber prepreg and the heat transfer printing membrane can be integrally formed; the steps of cutting and the like are included, so that precise operation such as precise alignment is not needed, the production process is greatly simplified, and the machining period is shortened; meanwhile, the heat transfer printing membrane and the glass fiber prepreg are attached in a hot-pressing mode, the binding force of the heat transfer printing membrane and the glass fiber prepreg is improved, and the problems of stripping and the like cannot occur in the long-term use process.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of composite material forming, and particularly relates to a composite material plate with a pattern, a preparation method thereof and an electronic product shell. BACKGROUND

[0002] In the field of consumer electronics, with the increasing demand of users for the portability, durability and personalized appearance of devices, composite materials gradually become the core shell material to replace traditional metals, plastics and glasses due to their lightweight and high-strength structural characteristics. Among them, glass fiber reinforced composite materials are widely used in the appearance shell manufacturing of smart phones, tablet computers, wearable devices and other products due to their high specific strength and good formability.

[0003] To meet the lightweight and high-strength structural characteristics and the appearance characteristics of the pattern decoration of the shell, the existing technology usually adopts the process route of "step forming + post-surface treatment": first, glass fibers are combined with a resin matrix by molding, injection molding and other methods to form a shell blank with basic structural strength; then, the surface of the shell blank is decorated by film lamination (such as heat transfer film, decorative film) or paint spraying (such as UV paint, color paint) to achieve texture, color and other appearance effects.

[0004] However, this process has significant defects: on the one hand, the step-by-step processing leads to low production efficiency, film lamination requires accurate alignment, paint spraying requires multiple drying and curing processes, and the single product processing cycle is long, which is difficult to adapt to the large-scale production demand of the consumer electronics industry; on the other hand, the equipment cost is high, film lamination requires special hot pressing equipment, paint spraying requires a dust-free workshop and a waste gas treatment system, and the post-processing process is easily affected by the flatness of the blank surface, resulting in a low yield. In addition, the adhesion between the film layer or the paint layer and the composite material substrate is limited, and problems such as peeling and wear are likely to occur during long-term use, affecting the service life and appearance consistency of the product.

[0005] Therefore, it is urgent to develop an integrated process that can integrate structural forming and appearance decoration to solve the problems of low efficiency, high cost and unstable performance in the prior art. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a composite material plate with a pattern and a preparation method thereof and an electronic product shell.

[0007] To achieve this application purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a preparation method of a composite material plate with a pattern, which comprises:

[0009] stacking and hot pressing the release film, the glass fiber semi-cured sheet and the heat transfer film in sequence to form an integrated body;

[0010] After the hot pressing is finished, the release film is removed, and the base material layer of the thermal transfer film piece is removed, to obtain the composite material plate with the pattern.

[0011] The application provides an integrated forming process for a composite material substrate and a thermal transfer film piece. The preparation method provided by the application can integrally form the glass fiber prepreg and the thermal transfer film piece. When applied to the appearance shell of an electronic product, the preparation method can save the lamination process of the film piece and the glass fiber plate, simplifies the manufacturing process, effectively improves the product productivity, only needs equipment such as hot pressing, and reduces the production cost.

[0012] Meanwhile, the preparation method provided by the application further includes steps such as cutting, so that precise alignment and other precise operations are not needed, the production process is greatly simplified, and the processing cycle is shortened; and the thermal transfer film piece and the glass fiber prepreg are laminated by hot pressing, the bonding force of the thermal transfer film piece and the glass fiber prepreg is improved, and peeling and other problems do not occur in the long-term use process.

[0013] Preferably, the temperature of the hot pressing is 110-150℃, for example, 110℃, 120℃, 130℃, 140℃, 150℃, etc., the time is 5-10min, for example, 5min, 6min, 7min, 8min, 9min, 10min, etc., and the forming pressure is 2-6MPa, for example, 2MPa, 3MPa, 3.5MPa, 4MPa, 5MPa, 6MPa, etc.

[0014] The application limits the temperature, time and pressure of the hot pressing. If the temperature, pressure or time of the hot pressing is too low, the bonding capacity of the glass fiber prepreg and the thermal transfer film piece cannot be guaranteed, and the glass fiber prepreg is prone to cracking in the application process. If the temperature, pressure or time of the hot pressing is too high, material structure damage, production efficiency reduction, warping and other defects are caused.

[0015] Preferably, the thickness of the glass fiber prepreg is greater than or equal to 0.2mm, for example, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.8mm, etc.

[0016] Preferably, the glass fiber plate prepreg includes at least two layers, and the thickness of each layer of the glass fiber prepreg is 0.05-0.15mm, for example, 0.05mm, 0.06mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, etc.

[0017] In the application, the introduction of at least two layers of glass fiber prepregs can guarantee that the composite material plate provided by the application has a certain thickness and mechanical properties, and can be better applied.

[0018] Preferably, the release film is a PC release film, and preferably the thickness of the PC release film is 0.2-0.3 mm, for example, 0.2 mm, 0.22 mm, 0.25 mm, 0.28 mm, 0.3 mm, etc.

[0019] The release film of the present invention is used as a demoulding material for hot pressing and can be removed after use.

[0020] Preferably, the method for preparing the thermal transfer film comprises:

[0021] (1) preparing an outer texture release layer on the substrate layer by transfer printing using UV release adhesive;

[0022] (2) applying a hardening liquid on the surface of the outer texture release layer and pre-curing it to form a first hardening liquid layer;

[0023] (3) After screen printing the intermediate varnish on the surface of the hardening liquid, the inner texture is transferred to form an inner texture layer;

[0024] (4) PVD coating is applied to the surface of the inner texture layer to enhance its brightness;

[0025] (5) After the coating, the bottom ink layer is silk-screened and then the adhesive film is laminated to form an adhesive layer to obtain the thermal transfer film.

[0026] Preferably, during the lamination, the adhesive film is close to one side of the glass fiber prepreg.

[0027] Preferably, the present invention can use a PC release film as the substrate layer, that is, in the present invention, the release material used in the hot pressing and the substrate layer used in the thermal transfer film are both PC release films.

[0028] Preferably, the preparation method comprises:

[0029] S1. Preparation of thermal transfer film;

[0030] S2 sequentially stack release film, glass fiber prepreg and thermal transfer film, and hot press;

[0031] S3. After the hot pressing is completed, the release film and the base layer of the thermal transfer film are removed, and the composite material plate with the pattern is obtained by cutting.

[0032] like Figure 1 As shown, the preparation method of the present invention comprises:

[0033] S1. Use a blanking machine to cut the fiberglass prepreg and thermal transfer film respectively;

[0034] S2. Optionally, preparing a thermal transfer film;

[0035] S3. Take the release film, the glass fiber prepreg and the thermal transfer film and stack them in sequence, that is, the glass fiber prepreg is located between the release film and the thermal transfer film;

[0036] S4. The structure set in S2 is sequentially stacked and hot-pressed to obtain a semi-finished product;

[0037] S5. removing the release film and the substrate layer of the thermal transfer film, and cutting the semi-finished product by CNC (Computer Numerical Control) to obtain the composite material plate with the pattern.

[0038] The present invention preferably controls the cutting process through CNC automation, thereby significantly improving production efficiency, reducing miscutting, improving product precision and quality, processing burrs and corners of the product, and solving the problem of fuzz on the product appearance.

[0039] The method provided by the present invention can improve product yield by 5-10%, reduce product cost by about 20%, and can be used for preparing electronic product appearance shells, etc., solving the current existing technical problems.

[0040] like Figure 2 As shown, the preparation method of the thermal transfer film of the present invention includes:

[0041] S21. Take a 0.2 mm release film and use UV release adhesive to transfer the outer texture release layer through a transfer process;

[0042] S22 in step S21 based on the coating 15-30 micron thick hardening liquid layer, 60-90 ℃ baking 30min;

[0043] S23. In step S22, based on the silk screen 5-15 micron thick intermediate varnish layer, the inner texture transfer glue transfer inner texture layer;

[0044] S24. Perform PVD coating brightening based on step S23;

[0045] S25. On the basis of step S24, a bottom ink layer is screen-printed and baked at 60-80° C. for 2 h.

[0046] S26. On the basis of step S25, a glue film is pasted to form an adhesive layer to obtain the thermal transfer film.

[0047] In a second aspect, the present invention provides a composite material plate with a pattern prepared by the preparation method described in the first aspect.

[0048] The composite material board of the present invention can be used as the appearance shell of electronic products, such as mobile phone shells, laptop shells, etc., and can also be used as protective shells of electronic products, etc.

[0049] Preferably, the thickness of the composite material plate is 0.2-0.8mm, such as 0.2mm, 0.4mm, 0.45mm, 0.5mm, 0.6mm, 0.8mm, etc.

[0050] In a third aspect, the present application provides an application of the patterned composite material plate of the second aspect in the preparation of an electronic product shell.

[0051] In a fourth aspect, the present application provides an electronic product appearance shell, wherein the electronic product back cover is made of the patterned composite material plate of the second aspect.

[0052] Compared with the prior art, the present application has the following beneficial effects:

[0053] (1) The present application provides an integrated forming process of a composite material substrate and a thermal transfer film, and the preparation method provided by the present application can integrally form the glass fiber prepreg and the thermal transfer film;

[0054] (2) The preparation method provided by the present application includes the steps of cutting, etc., so that precise alignment and other precise operations are not required, and the production process is greatly simplified, and the processing cycle is shortened;

[0055] (3) In the preparation method provided by the present application, the thermal transfer film and the glass fiber prepreg are hot-pressed and attached, which improves the bonding force of the thermal transfer film and the glass fiber prepreg, and does not cause peeling and other problems in the long-term use process;

[0056] (4) When the preparation method provided by the present application is applied to the manufacture of the appearance shell of an electronic product, the attachment process of the film and the glass fiber plate can be omitted, the manufacturing process is simplified, the product production rate is effectively improved, only hot-pressing equipment is required, and the production cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 The preparation method flow chart of the patterned composite material plate of the present application;

[0058] Figure 2 The preparation method flow chart of the thermal transfer film of the present application;

[0059] Figure 3 The simple structure diagram of the release film, the glass fiber prepreg and the thermal transfer film which are sequentially stacked according to the embodiment of the present application;

[0060] 1-thermal transfer film; 2-glass fiber prepreg; 21-first glass fiber prepreg; 22-second glass fiber prepreg; 23-third glass fiber prepreg; 3-PC release film. DETAILED DESCRIPTION

[0061] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0062] The present invention provides an integrated molding process for a composite material substrate and a thermal transfer film. That is, the method for preparing a composite material plate with a pattern provided by the present invention can enable a glass fiber prepreg and a thermal transfer film to be integrally molded. The method also includes steps such as cutting, thereby eliminating the need for precise operations such as accurate alignment, greatly simplifying the production process and shortening the processing cycle. At the same time, the thermal transfer film and the glass fiber prepreg are hot-pressed together, thereby improving the bonding strength between the thermal transfer film and the glass fiber prepreg, and preventing problems such as peeling during long-term use.

[0063] When applied to the exterior shell of an electronic product, the preparation method provided by the present invention can omit the lamination process of the diaphragm and the glass fiber board, simplify the production process, effectively improve the product productivity, and only require equipment such as hot pressing, thereby reducing production costs.

[0064] In the present invention, the thermal transfer film is any thermal transfer film in the prior art. The present invention again does not impose too many limitations, and only exemplifies the preparation method of the thermal transfer film:

[0065] The present invention provides a method for preparing a thermal transfer film, as follows:

[0066] (1) Take a 0.2 mm PC release film and use a UV release adhesive (such as polyurethane acrylate) to transfer the outer texture release layer through a transfer process;

[0067] (2) coating a 20 μm thick hardening liquid layer (e.g., polydipentaerythritol hexaacrylate, methyl isobutyl ketone, methyl ethyl ketone, etc.) on the basis of step (1), and baking at 80°C for 30 minutes;

[0068] (3) After screen printing a 10 μm thick intermediate varnish layer (e.g., polycarbonate modified resin, propylene glycol methyl ether acetate, tetramethylbenzene, etc.) on the basis of step (2), the inner texture transfer glue (e.g., polyurethane acrylate, etc.) is used to transfer the inner texture layer;

[0069] (4) Performing PVD coating brightening based on step (3);

[0070] (5) On the basis of step (4), a bottom ink layer (such as polyester resin, etc.) is screen-printed and baked at 70° C. for 2 h.

[0071] (6) On the basis of step (5), a glue film is pasted to form an adhesive layer to obtain the thermal transfer film.

[0072] The specific embodiments of the present invention are explained below by way of examples:

[0073] Preparation Example 1

[0074] This preparation example provides a method for preparing a thermal transfer film, as follows:

[0075] (1) Take a 0.2 mm PC release film and use UV release adhesive (polyurethane acrylate) to transfer the outer texture release layer through a transfer process;

[0076] (2) Apply 20 μm of hardening liquid (polydipentaerythritol hexaacrylate) on the basis of step (1) and bake at 80°C for 30 min;

[0077] (3) After screen printing a 10 μm thick intermediate varnish (polycarbonate modified resin) on the basis of step (2), the inner texture transfer glue (polyurethane acrylate) is used to transfer the inner texture layer;

[0078] (4) Performing PVD coating brightening based on step (3);

[0079] (5) On the basis of step (4), a bottom ink layer (polyester resin) was screen-printed and baked at 70° C. for 2 h.

[0080] (6) On the basis of step (5), a glue film is pasted to form an adhesive layer to obtain the thermal transfer film.

[0081] Example 1

[0082] This embodiment provides a method for preparing a composite material plate having a pattern, comprising:

[0083] S1. Use a blanking machine to cut epoxy resin glass fiber prepreg and PC release film respectively;

[0084] S2. Thermal transfer film preparation: See Preparation Example 1 for the specific preparation method;

[0085] S3. Take the release film (0.2mm), glass fiber prepreg and thermal transfer film, such as Figure 3 As shown, the release film, the glass fiber prepreg (three layers, each layer with a thickness of 0.1 mm) and the thermal transfer film are stacked in sequence, that is, the glass fiber prepreg is located between the release film and the thermal transfer film;

[0086] S4. The stacked structure is hot-pressed and integrally formed, wherein the hot pressing temperature is 120°C, the time is 8min, and the pressure is 6MPa to obtain a semi-finished product;

[0087] S5. removing the PC release film and the substrate layer PC release film of the thermal transfer film, and cutting the semi-finished product by CNC to obtain the composite material plate with the pattern, thereby obtaining a finished product.

[0088] Example 2

[0089] This embodiment provides a method for preparing a composite material plate having a pattern.

[0090] The only difference from Example 1 is that, in this embodiment, the temperature for hot pressing integral molding is 110° C., the time is 10 min, and the pressure is 2.5 MPa.

[0091] Example 3

[0092] This embodiment provides a method for preparing a composite material plate having a pattern.

[0093] The only difference from Example 1 is that, in this embodiment, the temperature for hot pressing integral molding is 150° C., the time is 5 minutes, and the pressure is 3 MPa.

[0094] Comparative Example 1

[0095] This comparative example provides a method for preparing a composite material plate with a pattern.

[0096] The only difference from Example 1 is that in this comparative example, the temperature for hot pressing integral molding is 90° C., the time is 10 min, and the pressure is 7 MPa.

[0097] Comparative Example 2

[0098] This comparative example provides a method for preparing a composite material plate with a pattern.

[0099] The only difference from Example 1 is that in this comparative example, the temperature for hot pressing integral molding is 160° C., the time is 10 min, and the pressure is 1 MPa.

[0100] Comparative Example 3

[0101] This comparative example provides a method for preparing a composite material plate having a pattern, as follows:

[0102] S1. Use a blanking machine to cut the glass fiber prepregs;

[0103] S2. Take the release film (0.2mm), glass fiber prepreg (three layers, each layer is 0.1mm thick) and stack them in sequence;

[0104] S3. The stacked structure is hot-pressed, wherein the hot pressing temperature is 120°C, the time is 8min, the pressure is 6MPa, and the release film is removed to obtain a glass fiber cured sheet;

[0105] S4. The fiberglass cured sheet is bonded to the adhesive film on the thermal transfer film and placed in a vacuum laminating machine for vacuum hot pressing at 120°C for 4 minutes. The backing layer of the thermal transfer film is removed, and the semi-finished product is cut and processed using CNC to obtain a patterned composite material board.

[0106] Comparative Example 4

[0107] The only difference from Comparative Example 3 is that in this comparative example, the glass fiber hot pressing temperature is 110° C., the time is 10 min, the pressure is 2.5 MPa, and the hot pressing bonding temperature is 110° C.*4 min.

[0108] Comparative Example 5

[0109] The difference from Comparative Example 3 is that the glass fiber hot pressing temperature is 150°C, the time is 5 minutes, the pressure is 3 MPa, and the hot pressing bonding temperature is 150°C*4 minutes.

[0110] Performance Testing

[0111] Yield rate testing and cost accounting were performed on the samples provided in Examples 1-3 and Comparative Examples 1-5 (multiple batches of samples were taken for inspection and the average was calculated). The results are shown in Table 1:

[0112] Table 1

[0113] sample Yield / % cost / % Example 1 80 80 Example 2 75 80 Example 3 75 80 Comparative Example 1 70 80 Comparative Example 2 70 80 Comparative Example 3 70 100 Comparative Example 4 65 100 Comparative Example 5 65 100

[0114] Note: The data in the above table are calculated based on the cost of the preparation method of the prior art provided in Comparative Example 1.

[0115] It can be seen from the examples and performance tests that the preparation method provided by the present invention can not only reduce the process preparation cost, but also improve the product yield.

[0116] From the comparison between Example 1 and Comparative Examples 1-2, it can be seen that the parameters of the hot pressing integral molding of the present invention need to be within the preferred range of the present invention in order to achieve better effects.

[0117] Comparative Examples 3-5 are the step-by-step molding methods commonly used in the current prior art. The hot pressing parameters and the hot pressing bonding temperature of Comparative Examples 3-5 correspond to the parameters in the preparation method provided in Examples 1-3. From the comparison between Examples 1-3 and Comparative Examples 3-5, it can be seen that the hot pressing integrated molding preparation method of the invention can not only reduce the process preparation cost, but also improve the product yield.

[0118] The applicant declares that while the above-described embodiments illustrate the technical solutions of the present invention, the present invention is not limited to the above-described process steps, nor does it imply that the present invention must rely on the above-described process steps for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a composite material plate with a pattern, characterized in that: The preparation method comprises: The release film, the glass fiber prepreg and the thermal transfer film are sequentially stacked and hot pressed into one piece; After the hot pressing is completed, the release film is removed, and the base material layer of the thermal transfer film is removed at the same time to obtain the composite material plate with the pattern.

2. The preparation method according to claim 1, characterized in that The hot pressing temperature is 110-150° C., the time is 5-10 minutes, and the molding pressure is 2-6 MPa.

3. The preparation method according to claim 1 or 2, characterized in that The thickness of the glass fiber prepreg is ≥0.2mm; Preferably, the glass fiber board prepreg comprises at least two layers, and the thickness of each layer of glass fiber prepreg is 0.05-0.15 mm.

4. The preparation method according to any one of claims 1 to 3, characterized in that The release film is a PC release film, and preferably the thickness of the PC release film is 0.2-0.3 mm.

5. The preparation method according to any one of claims 1 to 4, characterized in that The preparation method of the thermal transfer film comprises: (1) preparing an outer texture release layer on the substrate layer by transfer printing using UV release adhesive; (2) applying a hardening liquid on the surface of the outer texture release layer and pre-curing it to form a first hardening liquid layer; (3) After screen printing the intermediate varnish on the surface of the hardening liquid, the inner texture is transferred to form an inner texture layer; (4) the surface of the inner texture layer is sequentially subjected to PVD coating, silk screen printing of bottom ink, and adhesive film to obtain the thermal transfer film; Preferably, during the lamination, the adhesive film is close to one side of the glass fiber prepreg.

6. The preparation method according to any one of claims 1 to 5, characterized in that The preparation method comprises: S1. Preparation of thermal transfer film; S2 sequentially stack release film, glass fiber prepreg and thermal transfer film, and hot press; S3. After the hot pressing is completed, the release film and the base layer of the thermal transfer film are removed, and the composite material plate with the pattern is obtained by cutting.

7. A composite material plate with a pattern prepared by the preparation method according to any one of claims 1 to 6.

8. The composite material plate with pattern according to claim 7, characterized in that: The thickness of the composite material plate is 0.2-0.8 mm.

9. Use of the patterned composite material plate according to claim 7 or 8 in preparing electronic product housings.

10. An electronic product housing, characterized in that: The electronic product housing is made of the composite material plate with patterns according to claim 7 or 8.

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