A method for molding electronic appearance parts based on adhesive-coated ceramic powder

Abstract

This invention discloses a method for molding electronic appearance components based on adhesive-coated ceramic powder. The method includes the following steps: using a thermosetting adhesive as a matrix, adding ceramic powder and mixing and dispersing it evenly to obtain a fluid composite adhesive-ceramic slurry; injecting the composite adhesive-ceramic slurry into an electronic appearance component mold, heating and curing it at the curing temperature of the adhesive, demolding to obtain a preform; placing the preform in a sintering device and performing high-temperature sintering using a multi-gradient heating sintering process, causing the ceramic powder and the adhesive matrix to react in a solid phase to form a dense ceramic structure, cooling and demolding to obtain the finished electronic appearance component. This method significantly shortens the production cycle, provides excellent scratch and wear resistance, high gloss, and a delicate ceramic-like texture, meeting the performance and appearance requirements of high-end electronic appearance components.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, and in particular to a method for molding electronic appearance parts based on adhesives compounded into ceramic powder. Background Technology

[0002] Currently, electronic exterior components such as mobile phone frames, watch bezels, and decorative parts for smart wearable devices are mainly manufactured using processes such as metal CNC machining, traditional ceramic dry pressing / casting sintering, and plastic injection molding followed by spraying.

[0003] However, metal machining relies on high-precision CNC equipment, involves complex processing steps, high material loss rates, and long processing cycles for complex and irregular structures, resulting in high production costs and making it difficult to meet the demands of large-scale, efficient production. Traditional ceramic sintering processes require multiple steps, including powder forming, high-temperature densification sintering (usually above 1000℃), and precision grinding and polishing. These processes are complex, require significant equipment investment, and are prone to defects such as deformation and cracking during sintering, resulting in low yield rates and long overall production cycles. While plastic spraying offers convenient molding, the finished product has low surface hardness (usually below 3H), is easily scratched and worn, and has poor gloss and texture, making it difficult to meet the performance and appearance requirements of high-end electronic components.

[0004] It is evident that there is an urgent need for a manufacturing technology for electronic exterior parts that can balance ease of molding, low cost, high hardness, and a ceramic-like texture. Summary of the Invention

[0005] This invention provides a method for molding electronic appearance parts based on adhesive-coated ceramic powder, in order to solve the limitation that current manufacturing processes for electronic appearance parts cannot meet the performance requirements of high-end electronic appearance parts.

[0006] In a first aspect, the present invention provides a method for molding electronic appearance parts based on adhesive-coated ceramic powder, comprising the following steps: (1) Preparation of composite slurry: Using thermosetting adhesive as the matrix, add ceramic powder and mix and disperse evenly to obtain a fluid composite adhesive ceramic slurry; (2) Pre-curing and shaping: The composite adhesive is bonded into a ceramic slurry and injected into the mold of the electronic appearance part. It is then heated and cured at the curing temperature of the adhesive, demolded, and the preform is obtained. (3) High-temperature ceramicization: The preform is placed in a sintering equipment and sintered at high temperature using a multi-gradient heating sintering process, so that the ceramic powder reacts with the adhesive matrix to form a dense ceramic structure. After cooling and demolding, the finished electronic appearance part is obtained.

[0007] In some of the embodiments, the ceramic powder is a low-temperature ceramic powder, and its mass percentage in the composite adhesive ceramic slurry is 30% to 70%.

[0008] Optionally, the ceramic powder can be one or more of the JY series low-temperature ceramic powder and FR series ceramic powder from Anmi Micro-Nano New Materials (Guangzhou) Co., Ltd.

[0009] In some embodiments, the thermosetting adhesive is one or more of epoxy resin adhesive, polyurethane adhesive, phenolic resin adhesive, and silicone adhesive.

[0010] In some of these embodiments, in step (1), the mixing and dispersing stirring rate is 1000 rpm to 2000 rpm, and the stirring time is 25 min to 35 min.

[0011] In some of the embodiments, in step (2), the curing temperature is 60℃~150℃ and the curing time is 5min~30min.

[0012] In some embodiments, the multi-gradient heating sintering process includes: The temperature is increased to 400~550℃ at a heating rate of 5℃ / min and held for 20min~40min to cause the adhesive matrix to undergo organic matrix pyrolysis, main chain side group removal and main chain oxidation. Continue heating at a rate of 5℃ / min to 550℃~600℃ and hold for 20min~60min to melt the glass phase in the ceramic powder and form a glassy liquid phase to wet and bridge the inorganic filler. Continue heating at a rate of 5℃ / min to 600℃~800℃ to complete the solid-phase reaction.

[0013] Furthermore, the process of sintering the adhesive-coated ceramic powder using multi-gradient heating includes the following reaction stages: 1. During the pyrolysis stage at 400℃~550℃ (taking silicone adhesive as an example), the main chain side groups are removed, and the main chain is oxidized to produce amorphous SiO2: ; 2. During the 450℃~550℃ ceramic powder melting stage, low-melting-point glass powder softens and melts (physical phase transition): ; 3.550℃~600℃ liquid phase wetting and bridging stage: The liquid phase encapsulates SiO2 and inorganic fillers, forming bonding bridges (mainly physical bonding): ; 4. During the high-temperature sintering stage above 600℃, the glassy phase reacts with SiO2 and fillers in a solid-phase reaction to produce dense silicate ceramics. .

[0014] In a second aspect, the present invention also provides an electronic appearance component, which is manufactured based on the electronic appearance component molding method of adhesive-based composite ceramic powder as described in the first aspect, wherein the electronic appearance component has a surface hardness ≥5H and a surface gloss ≥80GU.

[0015] In some of these embodiments, the electronic appearance component includes a mobile phone frame, a watch bezel, or a decorative component for a smart wearable device.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. Simplified process and significantly improved efficiency: The adhesive is heated and cured to replace the traditional CNC machining and multi-stage ceramic sintering processes, which are complex. The molding time of a single workpiece is shortened (pre-curing is only 5-30 minutes), the production cycle is significantly shortened, and it is suitable for large-scale automated production. 2. Significantly reduced costs: By reducing high-precision processing equipment and complex process steps, material waste is reduced. High-end ceramic sintering equipment is not required, which greatly reduces equipment investment, labor and material costs. Compared with traditional processes, production costs can be reduced by more than 80%. 3. Strong structural adaptability: The adhesive can be molded into any shape, easily producing irregular and complex curved surface structures, solving the technical problem that traditional processes (such as ceramic sintering and metal machining) cannot process complex shapes, and greatly improving the freedom of product design; 4. Excellent performance meets standards: After being composited with ceramic powder and treated at high temperature, the surface hardness of the finished product can reach 5H or above, with excellent scratch and wear resistance. It also has high gloss and delicate imitation ceramic texture, comparable to traditional ceramic appearance parts, meeting the performance and appearance requirements of high-end electronic appearance parts. Detailed Implementation

[0017] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0018] As used herein, the terms “prepared from” and “comprising” are synonymous. The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0019] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, it should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Unless otherwise specified, the raw materials used in the following examples and comparative examples are commercially available industrial products, and all conditions not otherwise specified are conventional. Example 1

[0021] A method for forming a watch bezel includes the following steps: (1) Preparation of composite slurry: Using epoxy resin adhesive as the matrix, add 40% by mass of low temperature ceramic powder, place it in a high-speed stirring device and stir at 1200 rpm for 30 min to make the ceramic powder disperse evenly and obtain a fluid composite adhesive ceramic slurry. (2) Pre-curing and shaping: The composite adhesive is bonded into a ceramic slurry and injected into the watch bezel mold. It is placed in a heating furnace, heated to 120℃ and kept warm for 20 minutes to cure. The mold is then removed to obtain the watch bezel preform. (3) High-temperature ceramic forming: The preform is placed in a high-temperature sintering furnace and heated to 500°C at a heating rate of 5°C / min, and held for 40 min; then heated to 600°C at a heating rate of 5°C / min, and held for 50 min; then heated to 750°C at a heating rate of 5°C / min, and then cooled naturally and demolded to obtain the finished watch bezel. Example 2

[0022] A method for molding a mobile phone mid-frame includes the following steps: (1) Preparation of composite slurry: Using polyurethane adhesive as the matrix, add 70% by mass of low-temperature ceramic powder, place it in a high-speed stirring device and stir at 1000 rpm for 35 minutes to disperse the ceramic powder evenly and obtain a fluid composite adhesive ceramic slurry. (2) Pre-curing and shaping: The composite adhesive is bonded into a ceramic slurry and injected into the mobile phone frame mold. It is placed in a heating furnace, heated to 60°C and kept warm for 30 minutes to cure. The mold is then removed to obtain the pre-made mobile phone frame. (3) High-temperature ceramicization: The preform is placed in a high-temperature sintering furnace and heated to 400°C at a heating rate of 5°C / min, and held for 40 min; then heated to 550°C at a heating rate of 5°C / min, and held for 60 min; then heated to 650°C at a heating rate of 5°C / min, and then cooled naturally and demolded to obtain the finished mobile phone frame. Example 3

[0023] A method for molding a decorative part for a smart wearable device includes the following steps: (1) Preparation of composite slurry: Using phenolic resin adhesive as the matrix, add 30% by mass of low-temperature ceramic powder, place it in a high-speed stirring device and stir at 2000 rpm for 25 minutes to make the ceramic powder disperse evenly and obtain a fluid composite adhesive ceramic slurry. (2) Pre-curing and shaping: The composite adhesive is bonded into a ceramic slurry and injected into the mold of the irregular decorative part. It is placed in a heating furnace, heated to 150℃ and kept at the temperature for 5 minutes to cure. The mold is then removed to obtain the pre-made decorative part. (3) High-temperature ceramicization: The preform is placed in a high-temperature sintering furnace and heated to 550°C at a heating rate of 5°C / min, and held for 20 min; then heated to 600°C at a heating rate of 5°C / min, and held for 20 min; then heated to 800°C at a heating rate of 5°C / min, and then cooled naturally and demolded to obtain the finished decorative part.

[0024] Comparative Example 1 The difference from Example 1 is that no ceramic powder was added in Comparative Example 1.

[0025] Comparative Example 2 The difference from Example 1 is that Comparative Example 2 uses alumina / zirconia powder instead of ceramic powder.

[0026] Comparative Example 3 The difference from Example 1 is that Comparative Example 3 removes the adhesive and ceramic powder composite system, uses ceramic powder to fill the mold, and is sintered at a high temperature of 1200°C.

[0027] Comparative Example 4 The difference from Example 1 is that Comparative Example 4 directly enters step (3) after molding in step (2), instead of being placed in a heating oven for pre-curing.

[0028] Comparative Example 5 The difference from Example 1 is that Comparative Example 5 uses the following steps instead of step (3): the preform is placed in a high-temperature sintering furnace and heated to 600°C at a heating rate of 5°C / min. After holding at the temperature for 100 minutes, it is naturally cooled and demolded to obtain the finished watch bezel.

[0029] Performance testing The hardness of the finished product was tested according to GB / T 6739-2022, and the gloss of the finished product was tested according to GB / T 9754-2007. The test results are shown in Table 1.

[0030] Table 1 Performance test results of the examples and comparative examples

[0031] As shown in Table 1, the products obtained in Examples 1-3 have a hardness of 5.5H-6H and a gloss of 84-88 GU, all of which meet the requirements of hardness ≥5H and gloss ≥80 GU. Moreover, the products have no deformation or cracking and have a high yield. This indicates that the process of bonding adhesives into ceramic powder can replace traditional machining and ceramic sintering, and achieve rapid, low-cost and high-quality molding of electronic appearance parts.

[0032] Comparative Example 1, without the addition of ceramic powder, had a much lower hardness and gloss than Example 1, indicating that ceramic powder is the core component that gives the final product high hardness and high gloss. Simple thermosetting adhesives cannot form a ceramic structure after curing and cannot meet the performance requirements of appearance parts.

[0033] Comparative Example 2 showed that replacing the ceramic powder with alumina / zirconia powder resulted in a decrease in hardness and gloss performance. This indicates that the low-temperature ceramic powder can melt, wet, and undergo synergistic phase transformation at a lower temperature to form a dense ceramic layer. Ordinary ceramic powder does not possess this low-temperature ceramic forming characteristic and cannot be matched with the adhesive matrix to achieve effective ceramic forming.

[0034] Comparative Example 3, without adhesive, has comparable hardness and gloss to Example 1, but requires extreme high temperature (1200°C), high energy consumption, demanding equipment requirements, and the pure powder is difficult to mold into complex shapes.

[0035] Comparative Example 4, without pre-curing and shaping, had a hardness of only 3H. The gloss was not tested because direct high-temperature heating would cause the system to react and polymerize explosively, and the surface was bubbly and uneven. This shows that obtaining a well-shaped preform through adhesive curing is necessary to maintain structural integrity during the subsequent high-temperature ceramicizing process, prevent collapse and deformation, and ensure the dimensional accuracy and appearance of the final product.

[0036] Comparative Example 5, without segmented heat preservation, had significantly lower hardness and gloss than Example 1, indicating that the segmented step heating process is the key to forming a dense ceramic structure. Direct heating and heat preservation cannot effectively complete the processes of stepwise pyrolysis of the organic matrix, melting of the glass phase, liquid phase wetting and bridging, and solid phase reaction, resulting in a loose structure and poor gloss and hardness.

[0037] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0038] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for molding electronic appearance parts based on adhesive-coated ceramic powder, characterized in that, Includes the following steps: (1) Preparation of composite slurry: Using thermosetting adhesive as the matrix, add ceramic powder and mix and disperse evenly to obtain a fluid composite adhesive ceramic slurry; (2) Pre-curing and shaping: The composite adhesive is bonded into a ceramic slurry and injected into the mold of the electronic appearance part. It is then heated and cured at the curing temperature of the adhesive, demolded, and the preform is obtained. (3) High-temperature ceramicization: The preform is placed in a sintering equipment and sintered at high temperature using a multi-gradient heating sintering process, so that the ceramic powder reacts with the adhesive matrix to form a dense ceramic structure. After cooling and demolding, the finished electronic appearance part is obtained.

2. The method for molding electronic appearance parts based on adhesive-coated ceramic powder as described in claim 1, characterized in that, The ceramic powder is a low-temperature ceramic powder, and its mass percentage in the composite adhesive ceramic slurry is 30% to 70%.

3. The method for molding electronic appearance parts based on adhesive-coated ceramic powder as described in claim 1, characterized in that, The thermosetting adhesive is one or more of epoxy resin adhesive, polyurethane adhesive, phenolic resin adhesive, and silicone adhesive.

4. The method for molding electronic appearance parts based on adhesive-coated ceramic powder as described in claim 1, characterized in that, In step (1), the mixing and dispersing stirring rate is 1000rpm~2000rpm, and the stirring time is 25min~35min.

5. The method for molding electronic appearance parts based on adhesive-coated ceramic powder as described in claim 1, characterized in that, In step (2), the curing temperature is 60℃~150℃ and the curing time is 5min~30min.

6. The method for molding electronic appearance parts based on adhesive-coated ceramic powder as described in claim 1, characterized in that, The multi-gradient heating sintering process includes: The temperature is increased to 400~550℃ at a heating rate of 5℃ / min and held for 20min~40min to cause the adhesive matrix to undergo organic matrix pyrolysis, main chain side group removal and main chain oxidation. Continue heating at a rate of 5℃ / min to 550℃~600℃ and hold for 20min~60min to melt the glass phase in the ceramic powder and form a glassy liquid phase to wet and bridge the inorganic filler. Continue heating at a rate of 5℃ / min to 600℃~800℃ to complete the solid-phase reaction.

7. An electronic appearance component, characterized in that, The electronic appearance component is manufactured based on the electronic appearance component molding method according to any one of claims 1 to 6, which is based on adhesive composite ceramic powder, and the electronic appearance component has a surface hardness ≥5H and a surface gloss ≥80GU.

8. The electronic appearance component as described in claim 7, characterized in that, The electronic exterior components include mobile phone frames, watch bezels, or decorative parts for smart wearable devices.

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