An electrical device housing, a sub-film textured coating and a method of making the same

Abstract

The present application relates to the technical field of housings of electrical equipment, manufacturing of synthetic materials, coatings and the like, and provides an electrical equipment housing, a sub-film texture coating and a preparation method thereof, the electrical equipment housing has a decorative effect, the sub-film texture coating is used to form the decorative effect, and the sub-film texture coating comprises: 20-30% of polyurethane UV3 resin in terms of weight percentage, 40-60% of silicon modified 15 functional resin in terms of weight percentage, 10-20% of polyurethane acrylic resin in terms of weight percentage, 2-10% of hexanediol diacrylate in terms of weight percentage and 0.1-1% of a photoinitiator in terms of weight percentage. The VOC emission of the sub-film texture coating is very low, the environmental friendliness of a texture setting process of the electrical equipment housing can be improved, and the sub-film texture coating has good stretchability.

Description

Technical Field

[0001] This invention relates to the technical fields of electrical equipment housings, synthetic material manufacturing, and curing coatings, and particularly to an electrical equipment housing, a sub-film textured coating, and a method for preparing the same. Background Technology

[0002] In the design and production of casings for electronic devices such as mobile phones and tablets, as well as automotive interior parts, casings typically need to be designed with specific textures to achieve decorative effects in order to meet consumer demands for casing appearance. The design of these textures requires a series of texturing processes. These processes mainly involve applying a master texture coating to a textured mold to obtain a textured master film, and then applying a daughter texture coating to the master film to obtain a textured daughter film with decorative effects. The textured daughter film, as a film with a textured decorative effect, is then bonded to the casing substrate to form a textured and decorative electronic device casing. However, in existing technologies, the daughter film texture coatings have high VOC emissions and low environmental performance.

[0003] In summary, existing technologies for forming textures on the casings of electrical equipment suffer from problems such as high VOC emissions and low environmental performance of the sub-film texture coatings. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention provides an electrical equipment casing, a sub-film texture coating, and a method for preparing the same, thereby reducing VOC emissions from the sub-film texture coating and improving the environmental friendliness of the electrical equipment casing texture setting process.

[0005] In a first aspect, the present invention provides an electrical device housing having a decorative effect, the decorative effect being formed using a subfilm texture coating, the subfilm texture coating comprising: 20-30% by weight of polyurethane UV3 functional resin, 40-60% by weight of silicone-modified 15 functional resin, 10-20% by weight of polyurethane acrylic resin, 2-10% by weight of hexanediol diacrylate, and 0.1-1% by weight of photoinitiator.

[0006] In a second aspect, the present invention provides a subfilm texture coating comprising: 20-30% by weight of polyurethane UV3 functional resin, 40-60% by weight of silicone-modified 15 functional resin, 10-20% by weight of polyurethane acrylic resin, 2-10% by weight of hexanediol diacrylate, and 0.1-1% by weight of photoinitiator.

[0007] Thirdly, the present invention provides a method for preparing a sub-film textured coating, comprising:

[0008] Hexanediol diacrylate and photoinitiator were stirred and mixed to obtain the first mixture;

[0009] Polyurethane acrylic resin, silicone-modified 15-functional resin and polyurethane UV3-functional resin were added sequentially to the first mixture and stirred to obtain a second mixture.

[0010] The second mixture is subjected to degassing treatment to obtain the sub-film texture coating.

[0011] Compared with the prior art, the beneficial effects of this invention are as follows:

[0012] This invention provides an electrical equipment casing, a subfilm texture coating, and a method for preparing the same. The electrical equipment casing has a decorative effect, which is achieved using a subfilm texture coating. The subfilm texture coating comprises: 20-30% by weight of polyurethane UV3 functional resin, 40-60% by weight of silicone-modified 15 functional resin, 10-20% by weight of polyurethane acrylic resin, 2-10% by weight of hexanediol diacrylate, and 0.1-1% by weight of photoinitiator. The subfilm texture coating has very low VOC emissions, which can improve the environmental friendliness of the electrical equipment casing texture setting process. Furthermore, the subfilm texture coating has good tensile properties. Attached Figure Description

[0013] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. Some specific embodiments of the invention will be described in detail below with reference to the accompanying drawings in an exemplary and non-limiting manner. The same reference numerals in the drawings designate the same or similar parts or components. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the drawings:

[0014] Figure 1 This is a schematic flowchart of a method for preparing a sub-film textured coating according to an embodiment of the present invention.

[0015] Figure 2 This is a statistical chart of experimental data showing the characteristics of the test samples of the membrane texture coating in Embodiments 1 to 5 of the present invention. Detailed Implementation

[0016] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0017] Example 1

[0018] See Figures 1-2 This embodiment provides an electrical device housing with a decorative effect. The decorative effect is achieved using a subfilm texture coating, which comprises: 20-30% by weight of polyurethane UV3 functional resin, 40-60% by weight of silicone-modified 15 functional resin, 10-20% by weight of polyurethane acrylic resin, 2-10% by weight of hexanediol diacrylate, and 0.1-1% by weight of photoinitiator. The following specific implementation method can be used to produce the subfilm texture coating.

[0019] In Embodiment 1, the subfilm texture coating comprises: 25% by weight of polyurethane UV3 functional resin, 55% by weight of silicone-modified 15-functional resin, 15% by weight of polyurethane acrylic resin, 4% by weight of hexanediol diacrylate, and 1% by weight of photoinitiator. After the weight percentages are selected, the hexanediol diacrylate and photoinitiator are stirred and mixed, and then the polyurethane acrylic resin, silicone-modified 15-functional resin, and polyurethane UV3 functional resin are added sequentially and stirred. Degassing is then performed to obtain the subfilm texture coating.

[0020] In embodiment 2, the subfilm texture coating comprises: 20% by weight of polyurethane UV3 functional resin, 60% by weight of silicone-modified 15 functional resin, 10% by weight of polyurethane acrylic resin, 9.9% by weight of hexanediol diacrylate, and 0.1% by weight of photoinitiator. After selecting the weight percentages, the hexanediol diacrylate and photoinitiator are stirred and mixed, and then the polyurethane acrylic resin, silicone-modified 15 functional resin, and polyurethane UV3 functional resin are added sequentially and stirred. Degassing is then performed to obtain the subfilm texture coating.

[0021] In embodiment 3, the subfilm texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 50% by weight of silicone-modified 15-functional resin, 15% by weight of polyurethane acrylic resin, 4.5% by weight of hexanediol diacrylate, and 0.5% by weight of photoinitiator. After selecting the weight percentages, the hexanediol diacrylate and photoinitiator are stirred and mixed, and then the polyurethane acrylic resin, silicone-modified 15-functional resin, and polyurethane UV3 functional resin are added sequentially and stirred. Degassing is then performed to obtain the subfilm texture coating.

[0022] In embodiment 4, the subfilm texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 40% by weight of silicone-modified 15 functional resin, 20% by weight of polyurethane acrylic resin, 9% by weight of hexanediol diacrylate, and 1% by weight of photoinitiator. After selecting the weight percentages, the hexanediol diacrylate and photoinitiator are stirred and mixed, and then the polyurethane acrylic resin, silicone-modified 15 functional resin, and polyurethane UV3 functional resin are added sequentially and stirred. A degassing treatment is then performed to obtain the subfilm texture coating.

[0023] In embodiment 5, the subfilm texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 40% by weight of silicone-modified 15 functional resin, 19.4% by weight of polyurethane acrylate resin, 10% by weight of hexanediol diacrylate, and 0.6% by weight of photoinitiator. After selecting the weight percentages, the hexanediol diacrylate and photoinitiator are stirred and mixed, and then the polyurethane acrylate resin, silicone-modified 15 functional resin, and polyurethane UV3 functional resin are added sequentially and stirred. Degassing is then performed to obtain the subfilm texture coating.

[0024] It should be noted that, Figure 2 This demonstrates the characteristics of the test samples of the sub-film textured coatings used in embodiments 1 to 5. See also... Figure 2Polyurethane UV3 functional resin (PU(UV3)) provides certain flexibility, toughness, and impact resistance. Due to its polyurethane properties, it also contributes to good abrasion resistance and overall mechanical properties. Silicon-modified 15-functional resin is a high-functionality acrylic resin with the introduction of silicon groups, which often significantly improves crosslinking density, hardness, and weather resistance, and also helps with surface smoothness and hydrophobicity. However, excessive use may cause the system to become brittle or reduce elasticity. Polyurethane acrylic resin (PU acrylic) combines certain toughness and moderate hardness, improving adhesion, impact resistance, and flexural strength. The amount used affects overall flexibility and tensile properties. Hexanediol diacrylate (HDDA) is a typical bifunctional reactive diluent that can adjust viscosity and participate in crosslinking. Higher content often results in greater crosslinking density, higher hardness, modulus, and glass transition temperature (Tg), but often reduces elongation and impact performance. Photoinitiators determine the curing speed and degree of curing during UV curing. Too low a content may result in incomplete curing and unstable performance, while too high a content may lead to yellowing, odor, and other problems. In the above embodiments, the photoinitiator content is between 0.1% and 1%, which meets the curing requirements. Specifically, in embodiment 1, the content of silicone-modified 15-functional resin is relatively high (55%), resulting in a denser overall crosslinking network. However, due to the low HDDA content (4%), the dilution dosage of the system is low, and the crosslinking density is moderate. PU (UV3) accounts for 25%, and PU acrylic acid accounts for 15%, providing the system with a certain degree of flexibility and toughness, allowing for a moderately high elongation at break (e.g., 60-80%). The tensile strength and flexural strength of the test samples of the subfilm textured coating are at a moderate level (e.g., tensile strength 28-32 MPa), and the impact strength also shows good performance (12-14 kJ / m²). The high Tg (75-80℃) reflects the certain rigidity contribution brought by the high-functionality silicone resin. In Embodiment 2, the content of silicone-modified 15-functional resin is as high as 60%, and HDDA is also as high as 9.9%, resulting in a fairly high crosslinking density. PU(UV3) is only 20%, and PU acrylic acid is 10%, with relatively few flexible components, thus the elongation at break is usually low (e.g., 30-45%). The test samples of the film texture coating have high rigidity indicators such as tensile elastic modulus and flexural elastic modulus (e.g., 1100-1300 MPa, 1300-1500 MPa). Tensile strength and flexural strength also reach relatively high levels (e.g., 35-40 MPa, 45-50 MPa). Tg increases significantly (85-95℃), but toughness (impact strength) decreases slightly (9-11 kJ / m²), which is a common characteristic of high crosslinking density: "high modulus, low elongation". In Embodiment 3, compared to Embodiments 1 and 2, the PU(UV3) content is higher (30%), and the HDDA content is moderate (4.5%), thus the system is more elastic.While the content of silicone-modified 15-functional resin is also 50%, it is slightly lower than the 60% in Method 2, resulting in a slight decrease in overall crosslinking density and improved flexibility. Test samples of the subfilm textured coating showed high elongation at break (up to 70-90%), but slightly lower tensile and flexural strength (25-30 MPa, 30-35 MPa, respectively). Impact strength was good due to improved elasticity (13-15 kJ / m²). Tg was slightly lower (70-75℃), corresponding to a slight decrease in the rigidity of the crosslinking network. In Method 4, compared to Method 3, the content of silicone-modified 15-functional resin further decreased (40%), but HDDA increased to 9%. This has two effects: the low silicone-modified resin content results in a relatively reduced contribution from high-functionality branches, giving the material some flexibility; however, the high HDDA content of 9% enhances crosslinking and hardness, thus maintaining a moderately high overall crosslinking density. Simultaneously, the PU acrylic acid content was increased to 20%, also increasing toughness. The tensile and flexural strengths of the test samples of the subfilm textured coating were at a medium-to-high level (e.g., 32-36 MPa, 40-45 MPa), and the tensile modulus and elongation at break were also maintained in a balanced range (800-1000 MPa, 55-65%). The impact strength remained good (12-14 kJ / m²), and the Tg was around 80-85℃. In Embodiment 5, the overall structure was similar to Method 4, but the HDDA was increased to 10%, resulting in a further increase in crosslinking density compared to Embodiment 4. Since the total amount of PU(UV3) and PU acrylic acid was still relatively high, the toughness would not decrease excessively; however, the elongation would be slightly lower than that of Method 4 (45-60%). The tensile strength, flexural strength, and modulus of the test samples of the subfilm textured coating were improved (e.g., 35-40 MPa, 42-48 MPa, 900-1100 MPa - even 1200 MPa). The impact strength was close to or slightly lower than that of Method 4 (11-13 kJ / m²). Tg is approximately 80-90℃, slightly higher than in method 4.

[0025] In general, silicone-modified 15-functional resins have high multifunctionality. The silicone modification improves surface properties and weather resistance, and contributes to a higher crosslinking density. Higher dosages often result in higher hardness, modulus, and Tg, but elongation and impact toughness may decrease slightly. PU (UV3) and PU acrylic are both PU-based resins that enhance the system's flexibility, adhesion, and toughness. Higher content results in a softer and tougher material, often with better elongation at break and impact strength, but modulus and Tg may relatively decrease. HDDA (hexanediol diacrylate), a common bifunctional reactive diluent, forms a network structure during curing. Higher content increases the overall crosslinking density, improving material hardness, rigidity, and Tg, but elongation and impact strength tend to decrease.

[0026] In some preferred embodiments, a master film texture coating is applied to a textured mold and cured to form a textured master film. A daughter film texture coating is then applied to the master film, and after curing, it forms a textured daughter film with a decorative effect. This textured daughter film is then bonded to the substrate of the electrical equipment housing to obtain a decorative electrical equipment housing. It should be noted that applying the master film texture coating to the textured mold allows for precise replication of the minute texture structures on the mold surface. The fine textures on the mold can be completely replicated to the master film surface through the curing process of the master film texture coating, thus ensuring the accuracy and clarity of the texture. The function of the textured master film is to provide a precise and stable texture template, ensuring that the texture design is accurately presented on the final product. Furthermore, the textured master film formed after the master film texture coating has a certain strength and durability, effectively protecting the mold texture and ensuring that the texture is not damaged or deformed during subsequent operations due to operational or environmental influences. As an intermediate layer, the master film prevents the daughter film from directly contacting the mold surface and also reduces the risk of texture damage. Furthermore, in large-scale production, decorative textures can be replicated in batches and rapidly by using standardized molds and prefabricated master films, thereby improving production efficiency. In addition, both the master film and the daughter film are coated layers, cured using photoinitiators during the curing process, avoiding VOC emissions and improving the environmental performance of the production process, meeting the requirements of modern environmentally friendly manufacturing.

[0027] In some preferred embodiments, when the master film texture coating is applied to and cured on a textured mold, an LED cold light curing device is used to irradiate the master film texture coating applied to the mold, so that the master film texture coating is cured to form the textured master film. It should be noted that the light emitted by the LED cold light curing device has low heat, and during the curing process, excessive heat is not generated, thus protecting the mold and coating quality. Using cold light curing can reduce the decomposition or performance degradation of the coating due to overheating, ensuring the stability of the textured master film quality and avoiding surface defects or uneven curing. The LED curing device has high-precision light control, enabling uniform and directional irradiation. Uniform light ensures that the master film texture coating is cured evenly across the entire surface, thereby forming a clear and complete textured master film, without localized insufficient or over-curing. Furthermore, LED cold light curing has lower energy consumption compared to traditional UV lamps or high-temperature curing equipment, which can reduce energy consumption during the production process.

[0028] In some preferred embodiments, curing the sub-film textured coating applied to the textured master film includes: irradiating the sub-film textured coating applied to the textured master film with an LED cold light curing device to cure the sub-film textured coating with LED cold light. When the textured sub-film is bonded to the substrate of the electrical device housing, it includes: irradiating the textured sub-film with a mercury lamp curing device to bond the textured sub-film to the substrate of the electrical device housing. It should be noted that the LED cold light curing device generates less heat compared to traditional UV lamps or high-temperature curing devices. Excessive temperature during the curing of the sub-film textured coating can affect the already formed textured master film and sub-film coating, leading to film deformation, shrinkage, or surface defects. Using LED cold light curing can reduce thermal damage to the sub-film, ensuring the stability and uniformity of the coating structure. Mercury lamp curing devices can provide high-energy-density ultraviolet light, especially with strong irradiation capabilities in the UV-C band. For scenarios requiring high-intensity curing in a short time, mercury lamps can provide sufficient energy to ensure rapid and complete curing of the textured sub-film when bonded to the substrate. Compared to LED curing devices, mercury lamps can cure coatings much faster. The high energy output of mercury lamps allows for deep penetration between the subfilm and the substrate, achieving deep curing, which improves the adhesion strength of the coating and ensures that the cured subfilm has excellent physical properties, such as abrasion resistance, corrosion resistance, and high-temperature resistance.

[0029] In further preferred embodiments, the LED cold light curing of the subfilm textured coating includes: automatically controlling the LED cold light curing device to cure the subfilm textured coating with an appropriate light intensity and irradiation time based on the different weight percentages of the photoinitiator. It should be noted that the photoinitiator releases active substances under LED light irradiation, initiating the polymerization reaction of the resin in the subfilm textured coating, leading to coating curing. The weight percentage (concentration) of the photoinitiator directly determines the activity and efficiency of the photoreaction. If the photoinitiator concentration is high, the photocuring reaction rate is fast, and the required irradiation time can be shortened; if the photoinitiator concentration is low, the reaction rate is slow, requiring a longer irradiation time or a stronger light intensity to ensure sufficient curing. In this embodiment, by automatically adjusting the irradiation time of the LED cold light curing device according to the photoinitiator concentration, it can be ensured that the coating can be fully and uniformly cured under different formulations, avoiding problems of insufficient or over-curing. This improves the adaptability and flexibility of the curing process. Furthermore, the concentration of the photoinitiator affects the depth and speed of photocuring. When the photoinitiator concentration is low, the weak light intensity may not be able to penetrate the coating, resulting in rapid surface curing but insufficient deep curing and incomplete curing. Conversely, when the photoinitiator concentration is high, the high light intensity may cause the curing speed to be too fast, resulting in coating shrinkage, deformation, or surface defects. Therefore, the light intensity needs to be adjusted according to the initiator concentration to ensure that the coating can cure evenly and completely.

[0030] In further preferred embodiments, when the weight percentage of the photoinitiator is 0.1%, the light intensity is 500-700 mW / cm², and the irradiation time is 30-60 seconds; when the weight percentage of the photoinitiator is 0.5%, the light intensity is 300-500 mW / cm², and the irradiation time is 20-40 seconds; and when the weight percentage of the photoinitiator is 1%, the light intensity is 100-300 mW / cm², and the irradiation time is 10-20 seconds. It should be noted that when the photoinitiator concentration is 0.1%, the amount of initiator is relatively small, and the efficiency of light energy absorption is relatively low. To ensure sufficient curing, it is necessary to increase the light intensity and extend the irradiation time to provide more energy for the photoinitiator to activate and fully initiate the polymerization reaction. Low concentrations of photoinitiator may lead to insufficient curing reaction initiation, especially in areas with thick coatings or complex textures. Higher light intensity ensures that the initiator can absorb sufficient light energy, while longer irradiation time ensures that the initiator continues to function, preventing insufficient curing. When the photoinitiator concentration is 0.5%, the initiator concentration in the coating is moderate, enabling efficient absorption of light energy and initiation of the polymerization reaction. In this case, the light intensity and irradiation time can be maintained at a moderate level, ensuring rapid curing of the coating while avoiding localized over-curing caused by excessive initiator consumption. Moderate light intensity and irradiation time provide sufficient energy to the coating, ensuring uniform and efficient curing. Moderate light conditions guarantee the curing effect without causing excessively rapid curing that could lead to coating shrinkage or deformation. When the photoinitiator concentration is 1%, there is enough initiator in the coating to quickly absorb light energy and initiate the curing reaction. In this case, it is necessary to reduce the light intensity and shorten the irradiation time to avoid over-reaction, leading to problems such as excessively rapid curing, film shrinkage, and uneven surface hardening. Excessively high photoinitiator concentrations and strong light conditions may lead to over-curing, especially in the case of thicker coatings, where the surface cures too quickly while the interior remains insufficiently cured. By reducing the light intensity and irradiation time, a more uniform curing process can be ensured, preventing coating cracking or deformation caused by over-curing. Understandably, when the photoinitiator concentration is low (0.1%), it is necessary to increase the light intensity and extend the irradiation time to ensure sufficient curing reaction; when the concentration is moderate (0.5%), moderate light intensity and time can ensure efficient and uniform curing; while when the photoinitiator concentration is high (1%), it is necessary to reduce the light intensity and shorten the irradiation time to avoid over-curing or coating defects. This automated adjustment mechanism in this embodiment can ensure the curing effect of coatings under different formulations, improving process flexibility and product quality stability.

[0031] Example 2

[0032] See Figures 1-2This embodiment provides a subfilm texture coating, which comprises: 20-30% by weight of polyurethane UV3 functional resin, 40-60% by weight of silicone-modified 15 functional resin, 10-20% by weight of polyurethane acrylic resin, 2-10% by weight of hexanediol diacrylate, and 0.1-1% by weight of photoinitiator. The following specific implementation method can be used to produce the subfilm texture coating.

[0033] In Embodiment 1, the subfilm texture coating comprises: 25% by weight of polyurethane UV3 functional resin, 55% by weight of silicone-modified 15-functional resin, 15% by weight of polyurethane acrylic resin, 4% by weight of hexanediol diacrylate, and 1% by weight of photoinitiator. After the weight percentages are selected, the hexanediol diacrylate and photoinitiator are stirred and mixed, and then the polyurethane acrylic resin, silicone-modified 15-functional resin, and polyurethane UV3 functional resin are added sequentially and stirred. Degassing is then performed to obtain the subfilm texture coating.

[0034] In embodiment 2, the subfilm texture coating comprises: 20% by weight of polyurethane UV3 functional resin, 60% by weight of silicone-modified 15 functional resin, 10% by weight of polyurethane acrylic resin, 9.9% by weight of hexanediol diacrylate, and 0.1% by weight of photoinitiator. After selecting the weight percentages, the hexanediol diacrylate and photoinitiator are stirred and mixed, and then the polyurethane acrylic resin, silicone-modified 15 functional resin, and polyurethane UV3 functional resin are added sequentially and stirred. Degassing is then performed to obtain the subfilm texture coating.

[0035] In embodiment 3, the subfilm texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 50% by weight of silicone-modified 15-functional resin, 15% by weight of polyurethane acrylic resin, 4.5% by weight of hexanediol diacrylate, and 0.5% by weight of photoinitiator. After selecting the weight percentages, the hexanediol diacrylate and photoinitiator are stirred and mixed, and then the polyurethane acrylic resin, silicone-modified 15-functional resin, and polyurethane UV3 functional resin are added sequentially and stirred. Degassing is then performed to obtain the subfilm texture coating.

[0036] In embodiment 4, the subfilm texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 40% by weight of silicone-modified 15 functional resin, 20% by weight of polyurethane acrylic resin, 9% by weight of hexanediol diacrylate, and 1% by weight of photoinitiator. After selecting the weight percentages, the hexanediol diacrylate and photoinitiator are stirred and mixed, and then the polyurethane acrylic resin, silicone-modified 15 functional resin, and polyurethane UV3 functional resin are added sequentially and stirred. A degassing treatment is then performed to obtain the subfilm texture coating.

[0037] In embodiment 5, the subfilm texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 40% by weight of silicone-modified 15 functional resin, 19.4% by weight of polyurethane acrylate resin, 10% by weight of hexanediol diacrylate, and 0.6% by weight of photoinitiator. After selecting the weight percentages, the hexanediol diacrylate and photoinitiator are stirred and mixed, and then the polyurethane acrylate resin, silicone-modified 15 functional resin, and polyurethane UV3 functional resin are added sequentially and stirred. Degassing is then performed to obtain the subfilm texture coating.

[0038] It should be noted that, Figure 2 This demonstrates the characteristics of the test samples of the sub-film textured coatings used in embodiments 1 to 5. See also... Figure 2Polyurethane UV3 functional resin (PU(UV3)) provides certain flexibility, toughness, and impact resistance. Due to its polyurethane properties, it also contributes to good abrasion resistance and overall mechanical properties. Silicon-modified 15-functional resin is a high-functionality acrylic resin with the introduction of silicon groups, which often significantly improves crosslinking density, hardness, and weather resistance, and also helps with surface smoothness and hydrophobicity. However, excessive use may cause the system to become brittle or reduce elasticity. Polyurethane acrylic resin (PU acrylic) combines certain toughness and moderate hardness, improving adhesion, impact resistance, and flexural strength. The amount used affects overall flexibility and tensile properties. Hexanediol diacrylate (HDDA) is a typical bifunctional reactive diluent that can adjust viscosity and participate in crosslinking. Higher content often results in greater crosslinking density, higher hardness, modulus, and glass transition temperature (Tg), but often reduces elongation and impact performance. Photoinitiators determine the curing speed and degree of curing during UV curing. Too low a content may result in incomplete curing and unstable performance, while too high a content may lead to yellowing, odor, and other problems. In the above embodiments, the photoinitiator content is between 0.1% and 1%, which meets the curing requirements. Specifically, in embodiment 1, the content of silicone-modified 15-functional resin is relatively high (55%), resulting in a denser overall crosslinking network. However, due to the low HDDA content (4%), the dilution dosage of the system is low, and the crosslinking density is moderate. PU (UV3) accounts for 25%, and PU acrylic acid accounts for 15%, providing the system with a certain degree of flexibility and toughness, allowing for a moderately high elongation at break (e.g., 60-80%). The tensile strength and flexural strength of the test samples of the subfilm textured coating are at a moderate level (e.g., tensile strength 28-32 MPa), and the impact strength also shows good performance (12-14 kJ / m²). The high Tg (75-80℃) reflects the certain rigidity contribution brought by the high-functionality silicone resin. In Embodiment 2, the content of silicone-modified 15-functional resin is as high as 60%, and HDDA is also as high as 9.9%, resulting in a fairly high crosslinking density. PU(UV3) is only 20%, and PU acrylic acid is 10%, with relatively few flexible components, thus the elongation at break is usually low (e.g., 30-45%). The test samples of the film texture coating have high rigidity indicators such as tensile elastic modulus and flexural elastic modulus (e.g., 1100-1300 MPa, 1300-1500 MPa). Tensile strength and flexural strength also reach relatively high levels (e.g., 35-40 MPa, 45-50 MPa). Tg increases significantly (85-95℃), but toughness (impact strength) decreases slightly (9-11 kJ / m²), which is a common characteristic of high crosslinking density: "high modulus, low elongation". In Embodiment 3, compared to Embodiments 1 and 2, the PU(UV3) content is higher (30%), and the HDDA content is moderate (4.5%), thus the system is more elastic.While the content of silicone-modified 15-functional resin is also 50%, it is slightly lower than the 60% in Method 2, resulting in a slight decrease in overall crosslinking density and improved flexibility. Test samples of the subfilm textured coating showed high elongation at break (up to 70-90%), but slightly lower tensile and flexural strength (25-30 MPa, 30-35 MPa, respectively). Impact strength was good due to improved elasticity (13-15 kJ / m²). Tg was slightly lower (70-75℃), corresponding to a slight decrease in the rigidity of the crosslinking network. In Method 4, compared to Method 3, the content of silicone-modified 15-functional resin further decreased (40%), but HDDA increased to 9%. This has two effects: the low silicone-modified resin content results in a relatively reduced contribution from high-functionality branches, giving the material some flexibility; however, the high HDDA content of 9% enhances crosslinking and hardness, thus maintaining a moderately high overall crosslinking density. Simultaneously, the PU acrylic acid content was increased to 20%, also increasing toughness. The tensile and flexural strengths of the test samples of the subfilm textured coating were at a medium-to-high level (e.g., 32-36 MPa, 40-45 MPa), and the tensile modulus and elongation at break were also maintained in a balanced range (800-1000 MPa, 55-65%). The impact strength remained good (12-14 kJ / m²), and the Tg was around 80-85℃. In Embodiment 5, the overall structure was similar to Method 4, but the HDDA was increased to 10%, resulting in a further increase in crosslinking density compared to Embodiment 4. Since the total amount of PU(UV3) and PU acrylic acid was still relatively high, the toughness would not decrease excessively; however, the elongation would be slightly lower than that of Method 4 (45-60%). The tensile strength, flexural strength, and modulus of the test samples of the subfilm textured coating were improved (e.g., 35-40 MPa, 42-48 MPa, 900-1100 MPa - even 1200 MPa). The impact strength was close to or slightly lower than that of Method 4 (11-13 kJ / m²). Tg is approximately 80-90℃, slightly higher than in method 4.

[0039] In general, silicone-modified 15-functional resins have high multifunctionality. The silicone modification improves surface properties and weather resistance, and contributes to a higher crosslinking density. Higher dosages often result in higher hardness, modulus, and Tg, but elongation and impact toughness may decrease slightly. PU (UV3) and PU acrylic are both PU-based resins that enhance the system's flexibility, adhesion, and toughness. Higher content results in a softer and tougher material, often with better elongation at break and impact strength, but modulus and Tg may relatively decrease. HDDA (hexanediol diacrylate), a common bifunctional reactive diluent, forms a network structure during curing. Higher content increases the overall crosslinking density, improving material hardness, rigidity, and Tg, but elongation and impact strength tend to decrease.

[0040] Example 3

[0041] See Figure 1 This embodiment provides a method for preparing a sub-film textured coating, including the following steps:

[0042] S101. Hexanediol diacrylate and photoinitiator are stirred and mixed to obtain the first mixture;

[0043] S102. Polyurethane acrylic resin, silicone-modified 15-functional resin and polyurethane UV3-functional resin are added sequentially to the first mixture and stirred to obtain a second mixture.

[0044] S103. The second mixture is subjected to degassing treatment to obtain the sub-film texture coating.

[0045] It should be noted that in step S101, the hexanediol diacrylate and photoinitiator are mixed. Hexanediol diacrylate is a low-viscosity liquid with bifunctional groups, which is easy to mix uniformly with the photoinitiator. Stirring ensures that the photoinitiator is evenly distributed throughout the coating. This ensures that the photoinitiator can play a role in every part of the coating during the subsequent photocuring process, guaranteeing the uniformity of the curing reaction. Mixing the photoinitiator with the low-viscosity hexanediol diacrylate before mixing with other components helps to avoid premature reactions due to excessively high local concentrations when mixing other components. In addition, hexanediol diacrylate itself has good fluidity, and as a solvent or dispersion medium in the initial stage of the reaction, it can reduce the viscosity of the system, facilitating the uniform dispersion of the initiator. In step S102, polyurethane acrylic resin, silicone-modified 15-functional resin, and polyurethane UV3-functional resin are added sequentially and stirred. Polyurethane acrylic resin, silicone-modified 15-functional resin, and polyurethane UV3-functional resin are the main components of the subfilm textured coating, and each component has different physicochemical properties. Adding components sequentially and stirring helps avoid sudden increases in viscosity or uneven composition. Polyurethane acrylic resin is relatively soft and easily mixed with the first mixture, while the silicone-modified 15-functional resin and polyurethane UV3-functional resin are gradually mixed afterwards to ensure moderate overall system viscosity and easy uniform mixing. Adding these components gradually effectively controls viscosity changes, preventing uneven mixing or localized uneven distribution caused by adding high-viscosity materials all at once. Sequential addition ensures more thorough mixing and better resin dispersion. In step S103, air may be introduced into the mixture during the preceding stirring process, generating bubbles. The presence of bubbles can lead to a decrease in the mechanical properties of the coating, such as reduced adhesion strength and impacted structural uniformity after curing. Degassing improves the uniformity and stability of the coating, enhances the performance of the final film, and ensures the integrity and durability of the sub-film textured coating.

[0046] It is understandable that the first mixture refers to the mixture of hexanediol diacrylate and photoinitiator. Hexanediol diacrylate has low viscosity, so the first mixture behaves as a low-viscosity liquid, which helps the photoinitiator to be evenly distributed throughout the coating, ensuring uniform curing. Due to its low viscosity, the first mixture has good flowability, is easy to mix and disperse, and can effectively encapsulate and transfer the photoinitiator. In addition, hexanediol diacrylate is an active monomer containing diacrylate groups, which can undergo crosslinking reactions with subsequently added resins and form a solid structure through photocuring under the action of the photoinitiator. Its bifunctional groups can participate in resin crosslinking, improving the crosslinking density and strength of the final coating film. Since hexanediol diacrylate is a good solvent, the photoinitiator can be uniformly dissolved or dispersed in it, ensuring uniform reaction during curing. The second mixture refers to the mixture of the first mixture with polyurethane acrylic resin, silicone-modified 15-functional resin, and polyurethane UV3-functional resin. With the addition of polymeric resins (such as polyurethane acrylic resin and silicone-modified 15-functional resin), the viscosity of the second mixture gradually increases, becoming a medium- to high-viscosity liquid. Higher viscosity helps improve the film-forming properties of the coating, ensuring it can be well applied to the mold surface and form a uniform film layer. Polyurethane acrylic resin and silicone-modified 15-functional resin enhance the coating's toughness, weather resistance, and anti-yellowing properties, giving the cured coating excellent mechanical properties and long-term stability. Furthermore, the resin components in the second mixture (such as polyurethane UV3-functional resin and silicone-modified 15-functional resin) are the main film-forming materials and possess photocuring reactivity. Under the action of a photoinitiator, the acrylic groups of these resins can participate in the photocuring crosslinking reaction, forming a dense network structure and improving the strength and durability of the coating film. Polyurethane acrylic resin provides high toughness and impact resistance, silicone-modified 15-functional resin improves the coating's weather resistance and chemical corrosion resistance, while polyurethane UV3-functional resin provides good mechanical properties and transparency. The blending of these resins endows the coatings with a variety of properties, such as high strength, abrasion resistance, and UV resistance.

[0047] It should be noted that the sub-film textured coating contains a photoinitiator (0.1-1%), and the resin is cured by ultraviolet light, eliminating the need for solvents and significantly reducing VOC emissions. The UV curing system releases almost no organic matter during the curing process, meeting environmental protection requirements, while also accelerating the curing process and improving production efficiency. Silicone-modified 15-functional resins have advantages in reducing VOC emissions because they have high crosslinking density and solids content, providing excellent coating performance and reducing solvent use. Silicone-modified 15-functional resins also have good weather resistance, chemical resistance, and stain resistance, making them suitable for decorative coatings, especially in applications where appearance is crucial, such as mobile phones, tablets, and automotive interior parts. Polyurethane UV 3-functional resins and polyurethane acrylic resins also feature low VOC emissions.

[0048] It should also be noted that polyurethane UV3 functional resins possess excellent elasticity and flexibility. The molecular structure of polyurethane contains both soft and hard segments, providing excellent tensile strength and abrasion resistance, preventing the coating from easily breaking under tension and ensuring good flexibility in the textured coating. Polyurethane acrylic resin is an engineering plastic with high strength and high toughness. By modifying it and adding it to coatings, it can not only enhance the mechanical strength of the coating but also improve its ductility. Silicon-modified 15-functional resins have excellent flexibility and low modulus, which can improve the tensile strength of the coating. Hexanediol diacrylate is an reactive diluent that can improve the flowability and flexibility of the coating. It not only reduces the viscosity of the coating, making it easier to apply, but also enhances the toughness of the coating during the curing process.

[0049] In some preferred embodiments, when mixing hexanediol diacrylate and photoinitiator, the stirring speed is 1000 rpm and the stirring time is 10 minutes; when adding polyurethane acrylic resin, silicone-modified 15-functional resin and polyurethane UV3-functional resin sequentially to the first mixture and stirring, the stirring speed is 1200 rpm and the stirring time is 15 minutes; when degassing the second mixture, the degassing treatment time is 30 minutes.

[0050] It should be noted that the main function of the photoinitiator is to excite the reaction through ultraviolet or LED light, therefore its uniform dispersion throughout the coating is crucial. A moderate stirring speed of 1000 rpm effectively promotes the uniform dispersion of the photoinitiator in the low-viscosity hexanediol diacrylate without causing excessive bubble formation or localized deposition. Hexanediol diacrylate itself is a low-viscosity liquid, and a stirring time of 10 minutes is sufficient to ensure that the photoinitiator is completely and uniformly mixed into the liquid. Due to its low viscosity, a longer stirring time is unnecessary; 10 minutes of stirring ensures that the photoinitiator is evenly distributed in the coating, avoiding excessively high local concentrations or insufficient mixing due to too short a stirring time. Longer stirring times or higher speeds may introduce a large number of bubbles, especially in low-viscosity liquids. Therefore, controlling the speed at 1000 rpm ensures thorough mixing while minimizing bubble formation, reducing the difficulty of subsequent degassing. Furthermore, the viscosity of the mixture increases significantly after adding polyurethane acrylic resin, silicone-modified 15-functional resin, and polyurethane UV3-functional resin. These high-molecular-weight resins have high molecular weight and viscosity. A high stirring speed of 1200 rpm helps overcome the mixing difficulties caused by increased viscosity, ensuring that all components are fully mixed to form a homogeneous second mixture. Adding the resins sequentially and stirring avoids adding too much high-viscosity material at once, which can lead to uneven mixing. A stirring time of 15 minutes ensures that the resin components are gradually and evenly dispersed, resulting in a final mixture with ideal flowability and homogeneity. The stirring time and speed settings ensure that all resins are fully contacted and mixed, avoiding film defects or uneven curing caused by insufficient local mixing. Simultaneously, the active functional groups in the resins also need to be evenly distributed so that the subsequent photoinitiator can effectively trigger the cross-linking reaction during curing. High-viscosity systems are prone to air incorporation at 1200 rpm; therefore, a stirring time of 15 minutes ensures a homogeneous mixture without excessively extending the time to avoid introducing too many air bubbles. Air bubbles are inevitably introduced during stirring, especially in the high-viscosity second mixture. These bubbles can affect the uniformity and mechanical properties of the coating; the degassing treatment time is set to ensure that the air bubbles are completely removed. A 30-minute vacuum degassing time is sufficient to remove most air bubbles from the mixture, ensuring coating uniformity. If air bubbles are not completely removed, pores or bubble marks may appear in the coating after curing, affecting surface smoothness, optical effects, and mechanical properties. A 30-minute degassing treatment eliminates most air bubbles, facilitating smooth subsequent coating and curing processes.

[0051] In some further preferred embodiments, during the stirring process, a viscosity sensor monitors the viscosity change of the mixture. When the mixture reaches a preset viscosity range, the stirring time and speed of the stirrer are automatically adjusted. The viscosity sensor is a rotary viscosity sensor, installed at the bottom of the stirrer, with its probe in direct contact with the mixture. It should be noted that although standard parameters are set for the stirring time and speed, in practical applications, different batches of raw materials may have differences in viscosity and mixing difficulty. By monitoring the viscosity in real time and automatically adjusting the stirring time, uniform mixing of the initiator and epoxy resin can be ensured, avoiding inconsistencies caused by insufficient or excessive stirring. Automatic adjustment of the stirring time can shorten the waiting time during the preparation process, improve the overall efficiency of the production line, and avoid unnecessary excessive stirring.

[0052] In some further preferred embodiments, the vacuum degassing device includes a bubble detection sensor. After the stirrer completes stirring according to the automatically adjusted stirring speed and time, the bubble detection sensor monitors the number and size of bubbles in the cured coating in real time. When the bubbles are completely eliminated or the set minimum residual bubble level is reached, the vacuum degassing device automatically stops the degassing process. It should be noted that a fixed degassing time setting may cause some coatings to finish degassing before the bubbles are completely removed, or the bubbles may have been eliminated but the degassing time is still unnecessarily extended. Through the bubble detection sensor, the vacuum degassing device can intelligently determine the end point of the degassing process, ensuring complete bubble removal and guaranteeing the uniformity and quality of the coating. Prolonged vacuum degassing may cause changes in the properties of some materials or excessive water loss, affecting their final performance. By monitoring the bubble state in real time, the damage to the coating performance caused by prolonged degassing can be avoided, ensuring the integrity of the coating in terms of physical properties and structure. It should be noted that in this embodiment, the bubble detection sensor only starts working after stirring is completed, saving resources and computing power. Thus, the vacuum degassing device only needs to accurately monitor bubbles during the critical vacuum degassing stage, avoiding unnecessary monitoring work during stirring. This improves equipment efficiency while allowing focus on key quality control aspects of the degassing process. During stirring, bubbles detected by sensors may only be temporary due to mechanical agitation and could naturally dissipate during subsequent mixing or settling. Therefore, bubble detection during stirring can lead to false alarms or incorrect judgments. Monitoring after stirring is more precise, effectively monitoring residual bubbles in the mixture and allowing for degassing treatment.

[0053] It should be noted that the above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention, and the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An electrical equipment housing having a decorative effect, the formation of which uses a sub-film texture paint, characterized in that, The subfilm texture coating comprises: 20-30% by weight of polyurethane UV3 functional resin, 40-60% by weight of silicone-modified 15 functional resin, 10-20% by weight of polyurethane acrylic resin, 2-10% by weight of hexanediol diacrylate, and 0.1-1% by weight of photoinitiator. The method for preparing the sub-film texture coating includes: Hexanediol diacrylate and photoinitiator were stirred and mixed to obtain the first mixture; Polyurethane acrylic resin, silicone-modified 15-functional resin and polyurethane UV3-functional resin were added sequentially to the first mixture and stirred to obtain a second mixture. The second mixture is subjected to degassing treatment to obtain the sub-film texture coating; When mixing hexanediol diacrylate and photoinitiator, the stirring speed is 1000 rpm and the stirring time is 10 minutes. When adding polyurethane acrylic resin, silicone-modified 15-functional resin and polyurethane UV3-functional resin sequentially to the first mixture and stirring, the stirring speed is 1200 rpm and the stirring time is 15 minutes. When degassing the second mixture, the degassing time is 30 minutes. During the stirring process, the viscosity change of the mixture is monitored by a viscosity sensor. When the mixture reaches the preset viscosity range, the stirring time and stirring speed of the stirrer are automatically adjusted. The viscosity sensor is a rotary viscosity sensor, which is installed at the bottom of the stirrer, and the probe of the rotary viscosity sensor is in direct contact with the mixture. After the stirrer has finished stirring according to the automatically adjusted stirring speed and stirring time, the bubble detection sensor monitors the number and size of bubbles in the overall coating in real time. When the bubbles are completely eliminated or the set minimum residual bubble level is reached, the vacuum degassing device automatically stops the degassing process. The textured coating is applied to the textured master film and cured to form a textured sub-film with a decorative effect. After the textured sub-film is bonded to the substrate of the electrical equipment housing, a decorative electrical equipment housing is obtained. The textured master film is formed by applying the textured coating to a textured mold and curing it. When curing the sub-film texture coating applied to the texture master film, the process includes: irradiating the sub-film texture coating applied to the texture master film with an LED cold light curing device to cure the sub-film texture coating with LED cold light; when curing the sub-film texture coating with LED cold light, the process includes: automatically controlling the LED cold light curing device to cure the sub-film texture coating with an appropriate light intensity and irradiation time according to the different weight percentages of the photoinitiator.

2. The electrical device housing of claim 1, wherein, When the master film texture coating is applied to and cured on a textured mold, the process includes: using an LED cold light curing device to irradiate the master film texture coating applied to the mold, so that the master film texture coating is cured to form the textured master film.

3. The electrical device housing of claim 1, wherein, When the textured sub-film is bonded to the substrate of the electrical device housing, the process includes: irradiating the textured sub-film with a mercury lamp curing device to bond the textured sub-film to the substrate of the electrical device housing.

4. The electrical device housing of claim 1, wherein, The polyurethane UV3 functional resin has a weight percentage of 20%, the silicone-modified 15 functional resin has a weight percentage of 60%, the polyurethane acrylic resin has a weight percentage of 10%, the hexanediol diacrylate has a weight percentage of 9.9%, and the photoinitiator has a weight percentage of 0.1%.

5. The electrical device housing of claim 1, wherein, The polyurethane UV3 functional resin has a weight percentage of 25%, the silicone-modified 15 functional resin has a weight percentage of 55%, the polyurethane acrylic resin has a weight percentage of 15%, the hexanediol diacrylate has a weight percentage of 4%, and the photoinitiator has a weight percentage of 1%.

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