Electrical equipment shell, sub-film texture coating and preparation method thereof

Abstract

The invention relates to the technical field of shells of electrical equipment, manufacturing of synthetic materials, coatings and the like, and provides an electrical equipment shell, a sub-film texture coating and a preparation method thereof, the electrical equipment shell has a decorative effect, and the sub-film texture coating is used for forming the decorative effect. The sub-film texture coating is prepared from the following components in percentage by weight: 20 to 30 percent of polyurethane UV3 functional resin, 40 to 60 percent of silicon modified 15 functional resin, 10 to 20 percent of polyurethane acrylic resin, 2 to 10 percent of hexanediol diacrylate and 0.1 to 1 percent of photoinitiator. The VOC emission of the sub-film texture coating is very low, the environmental protection property of the electrical equipment shell texture setting process can be improved, and the sub-film texture coating is good in stretchability.

Description

Technical Field

[0001] The invention relates to the technical fields of housing of electric equipment, manufacture of synthetic materials, curing coatings, and the like, and in particular to a housing of electric equipment, a sub-film texture coating, and a preparation method thereof. Background Art

[0002] In the shell appearance design and production of electronic devices such as mobile phones and tablets, as well as automotive interior parts, in order to meet consumers' demand for shell appearance, the shell usually needs to be designed with a specific texture with decorative effects. Among them, the design of the shell texture requires a series of texture treatment processes. These texture treatment processes mainly include applying a mother film texture coating on a textured mold to obtain a textured mother film, and then applying a sub-film texture coating on the textured mother film to obtain a textured sub-film with a decorative effect. The textured sub-film, as a diaphragm with a textured decorative effect, can form an electrical equipment housing with a textured decorative effect after being bonded to the base material of the shell. In the prior art, the sub-film texture coating has high VOC emissions and low environmental performance.

[0003] In summary, in the prior art, the texture forming technology for the casing of electrical equipment has technical problems such as high VOC emissions of sub-film texture coatings and low environmental performance. Summary of the invention

[0004] In view of the deficiencies in the above-mentioned prior art, the present invention provides an electrical equipment housing, a sub-film texture coating and a preparation method thereof, so as to reduce the VOC emissions of the sub-film texture coating and improve the environmental friendliness of the electrical equipment housing texture setting process.

[0005] In a first aspect, the present invention provides an electrical equipment casing having a decorative effect, wherein a sub-film texture coating is used to form the decorative effect, wherein the sub-film texture coating comprises: 20-30% by weight of a polyurethane UV3-functional resin, 40-60% by weight of a silicon-modified 15-functional resin, 10-20% by weight of a polyurethane acrylic resin, 2-10% by weight of hexanediol diacrylate, and 0.1-1% by weight of a photoinitiator.

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

[0007] In a third aspect, the present invention provides a method for preparing a sub-film texture coating, comprising: Stirring and mixing hexanediol diacrylate and a photoinitiator to obtain a first mixture; Adding polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3-functional resin to the first mixture in sequence and stirring to obtain a second mixture; The second mixture is subjected to a degassing treatment to obtain the sub-film texture coating.

[0008] Compared with the prior art, the present invention has the following beneficial effects: The invention provides an electric equipment shell, a sub-film texture coating and a preparation method thereof. The electric equipment shell has a decorative effect. The sub-film texture coating is used to form the decorative effect. The sub-film texture coating comprises: 20-30% by weight of a polyurethane UV3-functional resin, 40-60% by weight of a silicon-modified 15-functional resin, 10-20% by weight of a polyurethane acrylic resin, 2-10% by weight of hexanediol diacrylate and 0.1-1% by weight of a photoinitiator. The sub-film texture coating has very low VOC emissions, can improve the environmental friendliness of a texture setting process for an electric equipment shell, and has good stretchability. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention and do not constitute an improper limitation of the present invention. Some specific embodiments of the present invention will be described in detail in an exemplary and non-restrictive manner with reference to the drawings. The same reference numerals in the drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 The present invention is a schematic flow chart of a method for preparing a sub-film texture coating according to an embodiment of the present invention.

[0010] Figure 2 It is a statistical graph of experimental data of the characteristics of the test samples of the sub-film texture coating in embodiments 1 to 5 of the present invention. DETAILED DESCRIPTION

[0011] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0012] Embodiment 1 See also Figure 1-Figure 2 This embodiment provides an electrical device housing, which has a decorative effect. The decorative effect is formed by using a sub-film texture coating, which includes: 20-30% by weight of polyurethane UV3-functional resin, 40-60% by weight of silicon-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 a photoinitiator. When producing the sub-film texture coating, the following specific implementation methods can be used.

[0013] Embodiment 1, the sub-film texture coating comprises: 25% by weight of polyurethane UV3 functional resin, 55% by weight of silicon-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 percentage is selected, the hexanediol diacrylate and the photoinitiator are stirred and mixed, and the polyurethane acrylic resin, silicon-modified 15 functional resin and polyurethane UV3 functional resin are added in sequence and stirred, and degassing treatment is performed to obtain the sub-film texture coating.

[0014] Embodiment 2, the sub-film texture coating comprises: 20% by weight of polyurethane UV3 functional resin, 60% by weight of silicon-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 the weight percentage is selected, the hexanediol diacrylate and the photoinitiator are stirred and mixed, and the polyurethane acrylic resin, silicon-modified 15 functional resin and polyurethane UV3 functional resin are added in sequence and stirred, and degassing treatment is performed to obtain the sub-film texture coating.

[0015] Embodiment 3, the sub-film texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 50% by weight of silicon-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 the weight percentage is selected, the hexanediol diacrylate and the photoinitiator are stirred and mixed, and the polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3 functional resin are added in sequence and stirred, and degassing treatment is performed to obtain the sub-film texture coating.

[0016] Embodiment 4, the sub-film texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 40% by weight of silicon-modified 15 functional resin, 20% by weight of polyurethane acrylic resin, 9% by weight of hexanediol diacrylate and 1% by weight of photoinitiator. After the weight percentage is selected, the hexanediol diacrylate and the photoinitiator are stirred and mixed, and the polyurethane acrylic resin, silicon-modified 15 functional resin and polyurethane UV3 functional resin are added in sequence and stirred, and degassing treatment is performed to obtain the sub-film texture coating.

[0017] Embodiment 5, the sub-film texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 40% by weight of silicon-modified 15 functional resin, 19.4% by weight of polyurethane acrylic resin, 10% by weight of hexanediol diacrylate and 0.6% by weight of photoinitiator. After the weight percentage is selected, the hexanediol diacrylate and the photoinitiator are stirred and mixed, and the polyurethane acrylic resin, silicon-modified 15 functional resin and polyurethane UV3 functional resin are added in sequence and stirred, and degassing treatment is performed to obtain the sub-film texture coating.

[0018] It should be noted that Figure 2 The characteristics of the test samples of the sub-film texture coating in embodiments 1 to 5 are reflected. Figure 2, polyurethane UV3 functional resin (abbreviated as PU(UV3)) can provide certain flexibility, toughness and impact resistance, and at the same time, due to its polyurethane characteristics, it can also contribute to good wear resistance and comprehensive mechanical properties. Silicone-modified 15-functional resin belongs to high-functionality acrylic resin, and the introduction of silicon groups (Silicone Modification) can often significantly improve the crosslinking density, hardness, weather resistance, and help with surface smoothness, hydrophobicity, etc. However, when the amount used is too high, it may also make the system brittle or reduce elasticity. Polyurethane acrylic resin (abbreviated as: PU acrylic) has certain toughness and moderate hardness, which can improve adhesion, impact resistance and bending resistance. The amount used will affect the overall flexibility and tensile properties. Hexanediol diacrylate (HDDA) is a typical difunctional active diluent that can adjust viscosity and participate in crosslinking. The higher the content, the greater the crosslinking density, the higher the hardness, modulus, and glass transition temperature (abbreviated as: Tg), but the elongation and impact performance tend to decrease. The photoinitiator determines the curing speed and degree of curing during the UV curing process. If the content is too low, incomplete curing and unstable performance may occur. If the content is too high, yellowing and odor may occur. In the above embodiments, the photoinitiator content is between 0.1-1%, which can meet the curing requirements. Specifically, in embodiment 1, the content of silicon-modified 15-functional resin is relatively high (55%), and the overall cross-linking network is relatively dense, but because HDDA is only 4%, the diluent amount of the system is low and the cross-linking density is moderate. PU (UV3) accounts for 25%, and PU acrylic acid accounts for 15%, which provides a certain flexibility and toughness for the system, and the elongation at break can be medium to high (such as 60-80%). The tensile strength and flexural strength of the test samples of the sub-film texture coating are at a medium level (for example, tensile strength 28-32MPa), and the impact strength also has a good performance (12-14 kJ / m²). Tg is relatively high (75-80℃), reflecting a certain rigidity contribution brought by high-functionality silicone resin. In implementation mode 2, the content of silicon-modified 15-functional resin is as high as 60%, and HDDA is as high as 9.9%, forming a fairly high crosslinking density. PU (UV3) is only 20%, PU acrylic acid is 10%, and the flexible component is relatively small, so the elongation at break is usually low (such as 30-45%). The test samples of the sub-film texture coating have high rigidity indicators such as tensile elastic modulus and bending elastic modulus (such as 1100-1300 MPa, 1300-1500 MPa). The tensile strength and bending strength also reach a high level (such as 35-40 MPa, 45-50MPa). Tg rises significantly (85-95℃), but the toughness (impact strength) will decrease slightly (9-11 kJ / m²), which is the "high modulus, low elongation" characteristic common to high crosslinking density. In implementation mode 3, compared with implementation modes 1 and 2, the PU (UV3) content is higher (30%), and the HDDA content is moderate (4.5%), so the system is more elastic.At the same time, although the content of silicon-modified 15-functional resin is also 50%, it is slightly lower than the 60% in method 2, which makes the overall cross-linking density slightly lower and the flexibility is improved. The test samples of the sub-film texture coating show high elongation at break (up to 70-90%), but the tensile strength and bending strength are slightly lower (25-30 MPa, 30-35 MPa). The impact strength is good due to the improved elasticity (13-15 kJ / m²). Tg is slightly lower (70-75℃), corresponding to a slight reduction in the rigidity of the cross-linked network. In embodiment 4, compared with embodiment 3, the content of silicon-modified 15-functional resin is further reduced (40%), but HDDA is increased to 9%, which will have two effects: low silicon-modified resin content brings relatively reduced high-functionality branch chain contribution, so that the material has a certain flexibility space; but up to 9% HDDA will enhance cross-linking and hardness, so the overall cross-linking density is still maintained at a medium to high level. At the same time, PU acrylic acid is increased to 20%, which also increases toughness. The tensile and flexural strengths of the test samples of the sub-film texture coating are at an upper-middle level (e.g., 32-36 MPa, 40-45 MPa), and the tensile elastic modulus and elongation at break are also maintained in a balanced range (800-1000 MPa, 55-65%). The impact strength is still good (12-14 kJ / m²), and the Tg is around 80-85°C. In implementation mode 5, the overall is similar to implementation mode 4, but the HDDA is increased to 10%, so that the crosslinking density is further increased compared with implementation mode 4. Since the total amount of PU (UV3) and PU acrylic acid is still high, the toughness will not decrease excessively; but the elongation will be slightly lower than that of implementation mode 4 (45-60%). The tensile strength, flexural strength and modulus of the test samples of the sub-film texture coating are improved (e.g., 35-40 MPa, 42-48 MPa, 900-1100 MPa-even 1200MPa). The impact strength is close to or slightly decreased from that of implementation mode 4 (11-13 kJ / m²). Tg is about 80-90℃, slightly higher than method 4.

[0019] In general, the multifunctionality of silicon-modified 15-functional resin is high, and the silicon-modified part can improve the surface performance and weather resistance, and contribute to a higher crosslinking density. The more the amount used, the higher the hardness, modulus, and Tg, but the elongation and impact toughness will decrease slightly. PU (UV3) and PU acrylic are both PU-based resins that can improve the flexibility, adhesion and toughness of the system. The higher the content, the softer and tougher the material, and the elongation at break and impact strength are often better, but the modulus and Tg may be relatively lower. HDDA (hexanediol diacrylate) is a common difunctional active diluent. HDDA will form a network structure during the curing process. The higher the content, the greater the overall crosslinking density, the harder, rigid, and Tg of the material, but the elongation and impact strength are prone to decrease.

[0020] In some preferred embodiments, the mother film texture coating is applied to a mold with a texture and cured to form a texture mother film, and the sub-film texture coating is applied to the texture mother film, and the sub-film texture coating is cured to form a texture sub-film with a decorative effect, and the texture sub-film is bonded to the substrate of the electrical device housing to obtain an electrical device housing with a decorative effect. It should be noted that the mother film texture coating is applied to a mold with a texture, and the micro-texture structure on the mold surface can be accurately replicated. The fine texture on the mold can be completely replicated to the mother film surface through the curing process of the mother film texture coating, thereby ensuring the accuracy and clarity of the texture. The role of the texture mother film is to provide an accurate and stable texture template to ensure that the texture design is accurately presented on the final product. In addition, the texture mother film formed after the mother film texture coating is cured has a certain strength and durability, which can effectively protect the mold texture and ensure that the texture will not be damaged or deformed due to operation or environmental influences in subsequent operations. The mother film, as an intermediate layer, prevents the sub-film from directly contacting the mold surface and reduces the risk of texture damage. In addition, in large-scale production, by using a unified mold and prefabricated master film, the decorative texture can be quickly replicated in batches, thereby improving production efficiency. In addition, both the master film and the daughter film are applied coating layers, and photoinitiators are used for curing during the curing process to avoid VOC emissions, improve the environmental performance of the production process, and meet the requirements of modern environmentally friendly manufacturing.

[0021] In some preferred embodiments, when the master film texture coating is applied to a mold with a texture and cured, 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 texture 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, no excessive heat is generated, thereby protecting the mold and coating quality. Using cold light curing can reduce the decomposition or performance degradation of the coating due to overheating, ensure the quality stability of the texture master film, and avoid surface defects or uneven curing. The LED curing device has a high-precision light control function, which can achieve uniform and directional irradiation. The uniform light ensures that the master film texture coating is uniformly cured on the entire surface, thereby forming a clear and complete texture master film, and there will be no local insufficient curing or over-curing. In addition, compared with traditional UV lamps or high-temperature curing equipment, LED cold light curing has lower energy consumption, which can reduce energy consumption in the production process.

[0022] In some preferred embodiments, when curing the sub-film texture coating applied on the texture mother film, it includes: using an LED cold light curing device to irradiate the sub-film texture coating applied on the texture mother film to perform LED cold light curing on the sub-film texture coating. When the texture sub-film is attached to the substrate of the electrical device housing, it includes: using a mercury lamp curing device to irradiate the texture sub-film so that the texture sub-film is attached to the substrate of the electrical device housing. It should be noted that the LED cold light curing device generates less heat than the traditional UV lamp or high temperature curing device. When curing the sub-film texture coating, excessively high temperature will affect the texture mother film and sub-film coating that have been formed, resulting in deformation, shrinkage or surface defects of the film layer. Using LED cold light curing can reduce thermal damage to the sub-film and ensure the stability and uniformity of the coating structure. The mercury lamp curing device can provide ultraviolet rays with higher energy density, especially with strong irradiation ability in the UV-C band. For scenes where high-intensity curing needs to be achieved in a short time, the mercury lamp can provide sufficient energy to ensure that the texture sub-film is quickly and fully cured when it is attached to the substrate. Compared with LED curing devices, mercury lamps can cure coatings more quickly. The high energy output of mercury lamps can penetrate deeply between the sub-film and the substrate to achieve deep curing, which can improve the bonding strength of the coating and ensure that the cured sub-film has excellent physical properties, such as wear resistance, corrosion resistance and high temperature resistance.

[0023] In some further preferred embodiments, when the sub-film texture coating is subjected to LED cold light curing, the method includes: automatically controlling the LED cold light curing device to cure the sub-film texture coating with an adapted light wave intensity and irradiation time according to the different weight percentages of the photoinitiator. It should be noted that the photoinitiator releases active substances under the irradiation of LED light, triggering the polymerization reaction of the resin in the sub-film texture coating, resulting in the curing of the coating. The weight percentage (concentration) of the photoinitiator can directly determine the activity and efficiency of the photoreaction. If the concentration of the photoinitiator is high, the photocuring reaction rate is fast, and the required irradiation time can be shortened; if the concentration of the photoinitiator is low, the reaction rate is slow, and a longer irradiation time or a stronger light intensity is required to ensure sufficient curing. In this embodiment, by automatically adjusting the irradiation time of the LED cold light curing device according to the concentration of the photoinitiator, it can be ensured that the coating can be fully and evenly cured under different formulations, avoiding the problem of insufficient curing or over-curing. This can improve the adaptability and flexibility of the curing process. In addition, the concentration of the photoinitiator affects the depth and speed of the photocuring. When the photoinitiator concentration is low, the weaker light intensity may not penetrate deep into the coating, resulting in faster curing of the surface layer but insufficient curing of the deep layer, causing incomplete curing. Conversely, when the photoinitiator concentration is high, the higher 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 be cured evenly and thoroughly.

[0024] In some further preferred embodiments, when the weight percentage of the photoinitiator is 0.1%, the light wave 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 wave intensity is 300-500 mW / cm², and the irradiation time is 20-40 seconds; when the weight percentage of the photoinitiator is 1%, the light wave intensity is 100-300 mW / cm², and the irradiation time is 10-20 seconds. It should be noted that when the concentration of the photoinitiator is 0.1%, the amount of initiator is small and the efficiency of absorbing light energy is relatively low. In order to ensure sufficient curing, it is necessary to increase the light wave intensity and extend the irradiation time to provide more energy to activate the photoinitiator and fully initiate the polymerization reaction. Low concentration of photoinitiator may lead to insufficient initiation of the curing reaction, especially in areas with thick coatings or complex textures. Higher light wave intensity ensures that the initiator can absorb sufficient light energy, and longer irradiation time ensures that the initiator can continue to work to prevent insufficient curing. When the photoinitiator concentration is 0.5%, the initiator concentration in the coating is moderate, which can absorb light energy and initiate polymerization reaction more efficiently. In this case, the light wave intensity and irradiation time can be kept at a moderate level, which can not only cure the coating quickly, but also avoid the problem of local over-curing caused by excessive consumption of initiator. Moderate intensity light waves and moderate irradiation time can provide enough energy for the coating to ensure uniform and efficient curing. Moderate lighting conditions can ensure the curing effect without causing too fast curing to cause shrinkage or deformation of the coating. When the photoinitiator concentration is 1%, there are enough initiators in the coating to quickly absorb light energy and start the curing reaction. In this case, it is necessary to reduce the light wave intensity and shorten the irradiation time to avoid excessive reaction, resulting in too fast curing, film shrinkage, uneven surface hardening and other problems. Too high a photoinitiator concentration and strong light conditions may lead to over-curing, especially in the case of thicker coatings, where the surface cures too quickly and the interior cures insufficiently. By reducing the light wave intensity and reducing the irradiation time, the curing process of the coating can be ensured to be more uniform, and the cracking or deformation of the coating caused by over-curing can be prevented. It is understandable that when the photoinitiator concentration is low (0.1%), it is necessary to increase the light wave intensity and extend the irradiation time to ensure sufficient curing reaction; when the concentration is moderate (0.5%), moderate light wave intensity and time can ensure efficient and uniform curing; and when the photoinitiator concentration is high (1%), it is necessary to reduce the light wave intensity and shorten the irradiation time to avoid over-curing or coating defects. This automatic adjustment mechanism in this embodiment can ensure the curing effect of the coating under different formulations, improve the flexibility of the process and the stability of product quality.

[0025] Embodiment 2 See also Figure 1-Figure 2The present embodiment provides a sub-film texture coating, the sub-film texture coating comprising: 20-30% by weight of polyurethane UV3-functional resin, 40-60% by weight of silicon-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. When producing the sub-film texture coating, the following specific implementation methods can be used.

[0026] Embodiment 1, the sub-film texture coating comprises: 25% by weight of polyurethane UV3 functional resin, 55% by weight of silicon-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 percentage is selected, the hexanediol diacrylate and the photoinitiator are stirred and mixed, and the polyurethane acrylic resin, silicon-modified 15 functional resin and polyurethane UV3 functional resin are added in sequence and stirred, and degassing treatment is performed to obtain the sub-film texture coating.

[0027] Embodiment 2, the sub-film texture coating comprises: 20% by weight of polyurethane UV3 functional resin, 60% by weight of silicon-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 the weight percentage is selected, the hexanediol diacrylate and the photoinitiator are stirred and mixed, and the polyurethane acrylic resin, silicon-modified 15 functional resin and polyurethane UV3 functional resin are added in sequence and stirred, and degassing treatment is performed to obtain the sub-film texture coating.

[0028] Embodiment 3, the sub-film texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 50% by weight of silicon-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 the weight percentage is selected, the hexanediol diacrylate and the photoinitiator are stirred and mixed, and the polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3 functional resin are added in sequence and stirred, and degassing treatment is performed to obtain the sub-film texture coating.

[0029] Embodiment 4, the sub-film texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 40% by weight of silicon-modified 15 functional resin, 20% by weight of polyurethane acrylic resin, 9% by weight of hexanediol diacrylate and 1% by weight of photoinitiator. After the weight percentage is selected, the hexanediol diacrylate and the photoinitiator are stirred and mixed, and the polyurethane acrylic resin, silicon-modified 15 functional resin and polyurethane UV3 functional resin are added in sequence and stirred, and degassing treatment is performed to obtain the sub-film texture coating.

[0030] Embodiment 5, the sub-film texture coating comprises: 30% by weight of polyurethane UV3 functional resin, 40% by weight of silicon-modified 15 functional resin, 19.4% by weight of polyurethane acrylic resin, 10% by weight of hexanediol diacrylate and 0.6% by weight of photoinitiator. After the weight percentage is selected, the hexanediol diacrylate and the photoinitiator are stirred and mixed, and the polyurethane acrylic resin, silicon-modified 15 functional resin and polyurethane UV3 functional resin are added in sequence and stirred, and degassing treatment is performed to obtain the sub-film texture coating.

[0031] It should be noted that Figure 2 The characteristics of the test samples of the sub-film texture coating in embodiments 1 to 5 are reflected. Figure 2, polyurethane UV3 functional resin (abbreviated as PU(UV3)) can provide certain flexibility, toughness and impact resistance, and at the same time, due to its polyurethane characteristics, it can also contribute to good wear resistance and comprehensive mechanical properties. Silicone-modified 15-functional resin belongs to high-functionality acrylic resin, and the introduction of silicon groups (Silicone Modification) can often significantly improve the crosslinking density, hardness, weather resistance, and help with surface smoothness, hydrophobicity, etc. However, when the amount used is too high, it may also make the system brittle or reduce elasticity. Polyurethane acrylic resin (abbreviated as: PU acrylic) has certain toughness and moderate hardness, which can improve adhesion, impact resistance and bending resistance. The amount used will affect the overall flexibility and tensile properties. Hexanediol diacrylate (HDDA) is a typical difunctional active diluent that can adjust viscosity and participate in crosslinking. The higher the content, the greater the crosslinking density, the higher the hardness, modulus, and glass transition temperature (abbreviated as: Tg), but the elongation and impact performance tend to decrease. The photoinitiator determines the curing speed and degree of curing during the UV curing process. If the content is too low, incomplete curing and unstable performance may occur. If the content is too high, yellowing and odor may occur. In the above embodiments, the photoinitiator content is between 0.1-1%, which can meet the curing requirements. Specifically, in embodiment 1, the content of silicon-modified 15-functional resin is relatively high (55%), and the overall cross-linking network is relatively dense, but because HDDA is only 4%, the diluent amount of the system is low and the cross-linking density is moderate. PU (UV3) accounts for 25%, and PU acrylic acid accounts for 15%, which provides a certain flexibility and toughness for the system, and the elongation at break can be medium to high (such as 60-80%). The tensile strength and flexural strength of the test samples of the sub-film texture coating are at a medium level (for example, tensile strength 28-32MPa), and the impact strength also has a good performance (12-14 kJ / m²). Tg is relatively high (75-80℃), reflecting a certain rigidity contribution brought by high-functionality silicone resin. In implementation mode 2, the content of silicon-modified 15-functional resin is as high as 60%, and HDDA is as high as 9.9%, forming a fairly high crosslinking density. PU (UV3) is only 20%, PU acrylic acid is 10%, and the flexible component is relatively small, so the elongation at break is usually low (such as 30-45%). The test samples of the sub-film texture coating have high rigidity indicators such as tensile elastic modulus and bending elastic modulus (such as 1100-1300 MPa, 1300-1500 MPa). The tensile strength and bending strength also reach a high level (such as 35-40 MPa, 45-50MPa). Tg rises significantly (85-95℃), but the toughness (impact strength) will decrease slightly (9-11 kJ / m²), which is the "high modulus, low elongation" characteristic common to high crosslinking density. In implementation mode 3, compared with implementation modes 1 and 2, the PU (UV3) content is higher (30%), and the HDDA content is moderate (4.5%), so the system is more elastic.At the same time, although the content of silicon-modified 15-functional resin is also 50%, it is slightly lower than the 60% in method 2, which makes the overall cross-linking density slightly lower and the flexibility is improved. The test samples of the sub-film texture coating show high elongation at break (up to 70-90%), but the tensile strength and bending strength are slightly lower (25-30 MPa, 30-35 MPa). The impact strength is good due to the improved elasticity (13-15 kJ / m²). Tg is slightly lower (70-75℃), corresponding to a slight reduction in the rigidity of the cross-linked network. In embodiment 4, compared with embodiment 3, the content of silicon-modified 15-functional resin is further reduced (40%), but HDDA is increased to 9%, which will have two effects: low silicon-modified resin content brings relatively reduced high-functionality branch chain contribution, so that the material has a certain flexibility space; but up to 9% HDDA will enhance cross-linking and hardness, so the overall cross-linking density is still maintained at a medium to high level. At the same time, PU acrylic acid is increased to 20%, which also increases toughness. The tensile and flexural strengths of the test samples of the sub-film texture coating are at an upper-middle level (e.g., 32-36 MPa, 40-45 MPa), and the tensile elastic modulus and elongation at break are also maintained in a balanced range (800-1000 MPa, 55-65%). The impact strength is still good (12-14 kJ / m²), and the Tg is around 80-85°C. In implementation mode 5, the overall is similar to implementation mode 4, but the HDDA is increased to 10%, so that the crosslinking density is further increased compared with implementation mode 4. Since the total amount of PU (UV3) and PU acrylic acid is still high, the toughness will not decrease excessively; but the elongation will be slightly lower than that of implementation mode 4 (45-60%). The tensile strength, flexural strength and modulus of the test samples of the sub-film texture coating are improved (e.g., 35-40 MPa, 42-48 MPa, 900-1100 MPa-even 1200MPa). The impact strength is close to or slightly decreased from that of implementation mode 4 (11-13 kJ / m²). Tg is about 80-90℃, slightly higher than method 4.

[0032] In general, the multifunctionality of silicon-modified 15-functional resin is high, and the silicon-modified part can improve the surface performance and weather resistance, and contribute to a higher crosslinking density. The more the amount used, the higher the hardness, modulus, and Tg, but the elongation and impact toughness will decrease slightly. PU (UV3) and PU acrylic are both PU-based resins that can improve the flexibility, adhesion and toughness of the system. The higher the content, the softer and tougher the material, and the elongation at break and impact strength are often better, but the modulus and Tg may be relatively lower. HDDA (hexanediol diacrylate) is a common difunctional active diluent. HDDA will form a network structure during the curing process. The higher the content, the greater the overall crosslinking density, the harder, rigid, and Tg of the material, but the elongation and impact strength are prone to decrease.

[0033] Embodiment 3 See also Figure 1 This embodiment provides a method for preparing a sub-film texture coating, comprising the following steps: S101, stirring and mixing hexanediol diacrylate and a photoinitiator to obtain a first mixture; S102, sequentially adding polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3-functional resin to the first mixture and stirring to obtain a second mixture; S103, performing a degassing treatment on the second mixture to obtain the sub-film texture coating.

[0034] It should be noted that in step S101, hexanediol diacrylate and photoinitiator are mixed. Hexanediol diacrylate is a low-viscosity liquid with a bifunctional group, which is easy to mix evenly with the photoinitiator. By stirring, the photoinitiator is ensured to be 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, ensuring the uniformity of the curing reaction. Before the photoinitiator is mixed with the low-viscosity hexanediol diacrylate with other components, it helps to avoid premature reaction due to excessive local concentration when mixing other components. In addition, hexanediol diacrylate itself has good fluidity. As a solvent or dispersion medium in the early stage of the reaction, it can reduce the viscosity of the system and facilitate the uniform dispersion of the initiator. In step S102, polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3-functional resin are added in sequence and stirred. Polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3-functional resin are the main components of the sub-film texture coating, and each component has different physical and chemical properties. Adding and stirring in sequence can avoid the problem of sudden increase in viscosity or uneven composition. Polyurethane acrylic resin is relatively soft and easier to mix with the first mixture, while the silicon-modified 15-functional resin and polyurethane UV3-functional resin are gradually mixed thereafter to ensure that the overall system viscosity is moderate and easy to stir evenly. When these ingredients are gradually added, the viscosity change of the system can be effectively controlled to avoid uneven mixing or uneven local distribution of materials caused by adding high-viscosity materials at one time. By adding in sequence, the mixing is more sufficient and the dispersion of the resin is better. In step S103, it is taken into account that air may be introduced into the mixture during the previous stirring process to produce bubbles. The presence of bubbles will cause the mechanical properties of the coating to decrease, such as reducing the adhesion strength and affecting the uniformity of the structure after curing. By degassing, the uniformity and stability of the coating can be improved, the performance of the final coating can be improved, and the integrity and durability of the sub-film texture coating can be ensured.

[0035] It is understood that the first mixture refers to a mixture of hexanediol diacrylate and a photoinitiator. Hexanediol diacrylate has a low viscosity, so the first mixture behaves as a low-viscosity liquid, which helps the photoinitiator to be evenly distributed throughout the coating and ensure subsequent uniform curing. Due to the low viscosity, the first mixture has good fluidity, is easy to mix and disperse, and can well wrap and transfer the photoinitiator. In addition, hexanediol diacrylate is an active monomer containing a diacrylate group, which can undergo a cross-linking reaction with the resin added later, and form a solid structure through a photocuring reaction under the action of a photoinitiator. Its bifunctional group can participate in the cross-linking of the resin and improve the cross-linking density and strength of the final coating. Since hexanediol diacrylate is a good solvent, the photoinitiator can be evenly dissolved or dispersed therein to ensure the uniformity of the reaction during curing. The second mixture refers to a mixture of the first mixture after adding polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3-functional resin. With the addition of polymer resins (such as polyurethane acrylic resins and silicon-modified 15-functional resins), the viscosity of the second mixture gradually increases and becomes a medium or high viscosity liquid. Higher viscosity helps to improve the film-forming property of the coating, ensuring that it can be well coated on the mold surface and form a uniform film layer. Polyurethane acrylic resins and silicon-modified 15-functional resins can enhance the toughness, weather resistance and anti-yellowing properties of the coating, so that the coating formed by the second mixture after curing has excellent mechanical properties and long-term stability. In addition, the resin components in the second mixture (such as polyurethane UV3-functional resins and silicon-modified 15-functional resins) are the main film-forming materials and have photocuring reaction activity. Under the action of photoinitiators, the acrylic groups of these resins can participate in the photocuring cross-linking reaction to form a dense network structure, thereby improving the strength and durability of the coating. Polyurethane acrylic resins provide higher toughness and impact resistance, silicon-modified 15-functional resins improve the weather resistance and chemical corrosion resistance of the coating, and polyurethane UV3-functional resins provide good mechanical properties and transparency. The mixture of these resins gives the coating a variety of properties, such as high strength, wear resistance, and UV resistance.

[0036] It should be noted that the sub-film texture coating contains a photoinitiator (0.1-1%), and the resin is cured by ultraviolet light, without the need for solvents, which significantly reduces VOC emissions. The UV curing system emits almost no organic matter during the curing process, which meets environmental protection requirements. At the same time, it can accelerate the curing process and improve production efficiency. Silicon-modified 15-functional resins have advantages in reducing VOC emissions because they have a high cross-linking density and solid content, can provide excellent coating properties, and reduce the use of solvents. Silicon-modified 15-functional resins also have good weather resistance, chemical resistance, and stain resistance, and are suitable for use in decorative coatings, especially in applications such as mobile phones, tablets, and automotive interiors that have high requirements for appearance. Polyurethane UV3-functional resins and polyurethane acrylic resins also have the characteristics of low VOC emissions.

[0037] It should also be noted that polyurethane UV3 functional resin has excellent elasticity and flexibility. The molecular structure of polyurethane contains soft segments and hard segments, which can provide good stretchability and wear resistance, so that the coating will not easily break when stretched, thereby ensuring that the sub-film texture coating has good flexibility. Polyurethane acrylic resin is an engineering plastic with high strength and high toughness. By modifying and adding it to the coating, it can not only enhance the mechanical strength of the coating, but also improve its ductility. Silicon-modified 15-functional resin has good flexibility and low modulus, which can improve the stretchability of the coating. Hexanediol diacrylate is an active diluent that can improve the fluidity and flexibility of the coating. It can not only reduce the viscosity of the coating and facilitate coating, but also improve the toughness of the coating during the curing process.

[0038] In some preferred embodiments, when hexanediol diacrylate and photoinitiator are stirred and mixed, the stirring speed is 1000 rpm and the stirring time is 10 minutes; when polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3-functional resin are added to the first mixture in sequence and stirred, the stirring speed is 1200 rpm and the stirring time is 15 minutes; when the second mixture is degassed, the degassed time is 30 minutes.

[0039] It should be noted that the main function of the photoinitiator is to stimulate the reaction through ultraviolet or LED light, so its uniform dispersion throughout the coating is crucial. The moderate stirring speed of 1000 rpm can effectively promote the uniform dispersion of the photoinitiator in the low-viscosity hexanediol diacrylate without causing excessive bubble formation or local 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 evenly mixed into the liquid. Due to the low viscosity, a longer stirring time is not necessary. 10 minutes of stirring can ensure that the photoinitiator is evenly distributed in the coating, avoiding local excessive concentration or insufficient mixing due to too short a time. Stirring for a longer time or at a higher speed may introduce a large number of bubbles, especially in low-viscosity liquids. Therefore, controlling the speed at 1000 rpm can minimize the generation of bubbles while ensuring sufficient mixing, reducing the difficulty of subsequent degassing. In addition, after adding polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3-functional resin, the viscosity of the mixed system will increase significantly. These polymer resins have high molecular weight and viscosity. The high stirring speed of 1200 rpm helps to overcome the mixing difficulty caused by the increased viscosity and ensure that the components can be fully mixed to form a uniform second mixture. Add the resins and stir in sequence to avoid adding too much high-viscosity material at one time, which will cause uneven stirring. The stirring time of 15 minutes can ensure that the resin components are gradually and evenly dispersed, so that the final mixture has ideal fluidity and uniformity. The setting of stirring time and speed ensures that all resins can be fully contacted and mixed, avoiding film formation defects or uneven curing caused by insufficient local mixing. At the same time, the active functional groups in the resin also need to be evenly distributed so that the subsequent photoinitiator can effectively trigger the cross-linking reaction during the curing process. The system with higher viscosity is easy to stir into air at a speed of 1200 rpm. Therefore, the stirring time is set to 15 minutes, which can ensure the uniformity of the mixture without excessively extending the time to avoid introducing too many bubbles. Bubbles are inevitably introduced during the stirring process, especially in the second mixture with higher viscosity. Bubbles may affect the uniformity and mechanical properties of the coating. The setting of the degassing treatment time is to ensure that the bubbles are completely removed. 30 minutes of vacuum degassing is long enough to remove most of the bubbles from the mixture and ensure uniformity of the coating. If the bubbles are not completely removed, pores or traces of bubbles may appear in the coating after curing, affecting surface flatness, optical effects and mechanical properties. 30 minutes of degassing can eliminate most of the bubbles, which helps the subsequent coating and curing process to proceed smoothly.

[0040] In some further preferred embodiments, during the stirring process, the viscosity change of the mixture is monitored by a viscosity sensor, and when the mixture reaches a preset viscosity range, the stirring time and stirring speed of the stirrer are automatically adjusted; the viscosity sensor is a rotary viscosity sensor, and the rotary viscosity sensor is installed at the bottom of the stirrer, and the probe of the rotary viscosity sensor is in direct contact with the mixture. It should be noted that although standard parameters are set for the stirring time and stirring speed, in actual applications, different batches of raw materials may have differences in viscosity and mixing difficulty. By real-time monitoring of viscosity and automatically adjusting the stirring time, uniform mixing of initiator and epoxy resin can be ensured, avoiding the inconsistency problem caused by insufficient artificial setting of time or excessive stirring. By automatically adjusting the stirring time, the waiting time in the preparation process can be shortened, the overall efficiency of the production line can be improved, and unnecessary excessive stirring can be avoided.

[0041] In some further preferred embodiments, the vacuum degassing device includes a bubble detection sensor. After the stirrer completes the stirring according to the automatically adjusted stirring speed and stirring time, the bubble detection sensor monitors the number and size of bubbles in the entire solidified 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 the fixed setting of the degassing time may cause some coatings to end degassing before the bubbles are completely removed, or the bubbles have been eliminated but the unnecessary time is still extended. Through the bubble detection sensor, the vacuum degassing device can intelligently determine the end point of the degassing process, ensure that the bubbles are completely removed, and ensure the uniformity and quality of the coating. Long-term vacuum degassing may cause the properties of some materials to change or excessive water loss, affecting their final performance. By monitoring the bubble state in real time, the damage to the coating performance caused by long-term degassing can be avoided, and the physical properties and structural integrity of the coating can be ensured. It should be noted that in this embodiment, the bubble detection sensor starts working after the stirring is completed, which can save resources and computing power. In this way, the vacuum degassing device only needs to accurately monitor the bubbles in the critical vacuum degassing stage to avoid wasting unnecessary monitoring work during stirring. This improves the efficiency of the equipment while focusing on the critical quality control link in the degassing process. During the stirring process, the bubbles that the sensor may detect are only temporary due to mechanical stirring, and they may dissipate naturally during subsequent mixing or static processing. Therefore, bubble detection during stirring may cause false alarms or misjudgments. Monitoring after stirring is more accurate and can effectively monitor the bubbles remaining in the mixture and degas these bubbles.

[0042] It should be pointed out that the above embodiments are only preferred specific implementation modes of the present invention, and the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. The protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An electrical equipment housing having a decorative effect, wherein a sub-film texture coating is used to form the decorative effect, characterized in that: The sub-film texture coating comprises: 20-30% by weight of polyurethane UV3-functional resin, 40-60% by weight of silicon-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.

2. The electrical equipment housing according to claim 1, characterized in that: The sub-film texture coating is applied on the texture mother film, and after curing, a texture sub-film with a decorative effect is formed. After the texture sub-film is bonded to the substrate of the electrical equipment casing, an electrical equipment casing with a decorative effect is obtained; the texture mother film is formed by applying the mother film texture coating on a mold with a texture and curing it.

3. The electrical equipment housing according to claim 2, characterized in that: When the mother film texture coating is coated on a mold with a texture and cured, it includes: using an LED cold light curing device to irradiate the mother film texture coating coated on the mold, so that the mother film texture coating is cured to form the texture mother film.

4. The electrical equipment housing according to claim 2, characterized in that: When curing the sub-film texture coating applied on the texture mother film, it includes: using an LED cold light curing device to irradiate the sub-film texture coating applied on the texture mother film to perform LED cold light curing on the sub-film texture coating.

5. The electrical equipment housing according to claim 2, characterized in that: When the texture sub-film is bonded to the substrate of the electrical device housing, the method includes: using a mercury lamp curing device to irradiate the texture sub-film so that the texture sub-film is bonded to the substrate of the electrical device housing.

6. A sub-film texture coating, characterized in that: include: 20-30% by weight of polyurethane UV3-functional resin, 40-60% by weight of silicon-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.

7. A method for preparing a sub-film texture coating, characterized in that: include: Stirring and mixing hexanediol diacrylate and a photoinitiator to obtain a first mixture; Adding polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3-functional resin to the first mixture in sequence and stirring to obtain a second mixture; The second mixture is subjected to a degassing treatment to obtain the sub-film texture coating.

8. The method for preparing an electrical equipment housing according to claim 7, characterized in that: The weight percentage of the polyurethane UV3 functional resin is 20%, the weight percentage of the silicon-modified 15-functional resin is 60%, the weight percentage of the polyurethane acrylic resin is 10%, the weight percentage of the hexanediol diacrylate is 9.9%, and the weight percentage of the photoinitiator is 0.1%.

9. The method for preparing an electrical equipment housing according to claim 7, characterized in that: The weight percentage of the polyurethane UV3 functional resin is 25%, the weight percentage of the silicon-modified 15-functional resin is 55%, the weight percentage of the polyurethane acrylic resin is 15%, the weight percentage of the hexanediol diacrylate is 4%, and the weight percentage of the photoinitiator is 1%.

10. The method for preparing an electrical equipment housing according to claim 7, characterized in that: When hexanediol diacrylate and photoinitiator are stirred and mixed, the stirring speed is 1000 rpm and the stirring time is 10 minutes; when polyurethane acrylic resin, silicon-modified 15-functional resin and polyurethane UV3-functional resin are added to the first mixture in sequence and stirred, the stirring speed is 1200 rpm and the stirring time is 15 minutes; when the second mixture is degassed, the degassed time is 30 minutes.

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