High-weather-resistance UV nano coating and preparation method thereof

Abstract

The invention belongs to the technical field of coatings, and relates to a high-weather-resistance UV nano coating and a preparation method thereof.The coating comprises a UV finish paint layer, a vacuum coating layer and a UV primer layer which are sequentially arranged from outside to inside; the UV finish paint layer is composed of at least two sub UV finish paint layers, each sub UV finish paint layer contains a nanometer strengthening phase, and the concentration of the nanometer strengthening phase of each sub UV finish paint layer is gradually decreased from outside to inside in a gradient mode. The defects of an existing coating in the aspects of weather resistance, decorative effect and physical and mechanical properties are effectively overcome, a brand new high-performance coating structure is constructed by ingeniously combining a UV curing technology, a vacuum coating technology and a nanometer strengthening technology, and comprehensive improvement of the coating performance is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings and relates to a highly weather-resistant UV nano-coating and a preparation method thereof. Background Art

[0002] With the rapid development of technology and the continuous improvement of industrial application requirements, more stringent requirements are put forward for the coating performance of material surfaces. When facing extreme environmental conditions, traditional coatings often exhibit problems such as poor weather resistance, easy fading of decorative effects, and insufficient mechanical properties.

[0003] As an efficient and environmentally friendly coating curing method, UV curing technology has been widely used in the coating industry due to its advantages such as rapid curing, low energy consumption, and low VOC emissions. However, when using UV-cured coatings alone, their weather resistance and mechanical properties still need to be improved. Especially when exposed to harsh environments such as ultraviolet rays, high temperature, and high humidity for a long time, the coatings are prone to aging, cracking, and discoloration. Vacuum coating technology is well-known for its ability to form a uniform, dense, and highly glossy metal or non-metal thin film layer on the material surface, providing excellent decorative effects and certain protective functions for the coatings. However, the weather resistance and scratch resistance of the vacuum coating layer itself are limited, and it is difficult to meet the long-term use requirements under complex environments alone. Therefore, it is particularly important to develop a new type of coating that has both high weather resistance and good decorative effects and mechanical properties.

[0004] Nano-reinforcement technology, as an important breakthrough in the field of materials science in recent years, significantly improves the mechanical properties, thermal stability, and weather resistance of materials by introducing nano-scale particles or fibers as reinforcement phases. The characteristics of the nano-reinforcement phase such as small size effect, surface effect, and quantum size effect make it have unique advantages in improving material properties. Applying nano-reinforcement technology to the coating field can not only enhance the physical and mechanical properties of the coatings, such as hardness, wear resistance, and scratch resistance, but also improve the weather resistance and corrosion resistance of the coatings. This provides a new idea for solving the deficiencies of UV-cured coatings and vacuum coating layers in terms of weather resistance.

[0005] In view of this, there is an urgent need to propose a new type of coating to solve the deficiencies of existing coatings in terms of weather resistance, decorative effects, and mechanical properties, and to meet the stringent requirements of modern industrial scenarios for coating performance. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a highly weather-resistant UV nano-coating and a preparation method thereof. This coating organically combines UV curing technology, vacuum coating technology, and nano-reinforcement technology to solve the deficiencies of existing coatings in terms of weather resistance, decorative effects, and mechanical properties, and thus meet the stringent requirements of modern industrial scenarios for coating performance.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A highly weather-resistant UV nano-coating, comprising a UV topcoat layer, a vacuum coating layer, and a UV primer layer arranged in sequence from the surface to the inside;

[0009] The UV topcoat layer is composed of at least two sub-UV topcoat layers. Each sub-UV topcoat layer contains a nano-reinforcing phase, and the concentration of the nano-reinforcing phase in the sub-UV topcoat layer shows a gradient change decreasing in sequence from the surface to the inside.

[0010] In view of the respective advantages of UV curing technology, vacuum coating technology, and nano-reinforcing technology, the present invention combines the three technologies to construct a brand-new high-performance UV nano-coating, which solves the problems of insufficient decorative effect, weather resistance, and mechanical properties of traditional coatings; and through reasonable design of the coating structure, the UV primer layer, the vacuum coating layer, and the nano-reinforced UV topcoat layer are organically combined, which can give full play to their respective advantages and achieve a comprehensive improvement in the coating performance. The UV primer layer provides good adhesion and flexibility; the vacuum coating layer endows the coating with a unique decorative effect; the nano-reinforced UV topcoat layer, through the gradient change of the nano-reinforcing phase concentration, where the nano-reinforcing phase concentration of the sub-UV topcoat layer close to the surface layer is extremely high and the thickness is extremely thin, enables the surface layer to fully reflect ultraviolet rays and also improves comprehensive properties such as scratch resistance, wear resistance, and corrosion resistance; the lower the concentration of the nano-reinforcing phase closer to the vacuum coating layer, and it mainly plays a role in absorbing ultraviolet rays and reducing the ultraviolet ray scattering path length inside, which can maximize the shielding effect of the nano-reinforcing phase on ultraviolet rays, thereby obtaining high weather resistance, and the gradual change in concentration helps to release stress in the coating. Through this gradient change design of the nano-reinforcing phase concentration, high weather resistance and excellent protection can be achieved simultaneously, providing a brand-new solution for the surface protection of high-end industrial products.

[0011] Further, the total thickness of the coating is 10 - 100 μm, the thickness of the UV primer layer is 5 - 40 μm, the thickness of the vacuum coating layer is 0.1 - 1 μm, the thickness of the UV topcoat layer is 5 - 60 μm, and the thickness of the sub-UV topcoat layer arranged on the outermost surface is 1 - 10 μm.

[0012] Further, the thickness of the sub-UV topcoat layer arranged closest to the vacuum coating layer in the UV topcoat layer is greater than the thickness of the sub-UV topcoat layer arranged on the outermost surface.

[0013] Further, the nano-reinforcing phase in the UV topcoat layer is nano-SiO 2 , nano-TiO 2 , nano-ZnO, nano-CeO 2 , nano-ZrO 2 , nano-Al 2 O3 , nano-Fe 2 O 3 , one or more of carbon nanotubes and graphene, and the particle size of the nano-reinforcing phase is in the range of 1 to 500 nm.

[0014] Furthermore, for coatings with high gloss requirements, the particle size of the nano-reinforcing phase is preferably in the range of 1 to 50 nm.

[0015] Furthermore, the nano-reinforcing phase concentration in the sub-UV topcoat layer arranged on the outermost layer of the UV topcoat layer is 20 to 60 wt.%, and the nano-reinforcing phase concentration in the sub-UV topcoat layer arranged on the innermost layer is 0.5 to 20 wt.%.

[0016] On the other hand, the present invention also provides a method for preparing a high weather-resistant UV nano-coating, which is characterized by including the following steps:

[0017] Step 1. Coating a UV coating on a substrate to prepare a UV primer layer;

[0018] Step 2. Preparing a vacuum coating layer on the UV primer layer by using a vacuum coating technology;

[0019] Step 3. Coating at least two layers of nano-modified UV coatings with different nano-reinforcing phase concentrations on the vacuum coating layer to prepare a UV topcoat layer, and controlling the nano-reinforcing phase concentration of the UV topcoat layer to show a gradient change decreasing from the surface to the inside.

[0020] Furthermore, the nano-modified UV coating is prepared by a dilution evaporation production method, and the specific preparation steps are as follows:

[0021] First, add the nano-reinforcing phase to the coating to form a slurry masterbatch, then add an organic solvent to form a diluent. After the diluent is mixed evenly, evaporate the organic solvent. Finally, add different amounts of coating in batches according to needs and stir to obtain nano-modified UV coatings with different nano-reinforcing phase concentrations.

[0022] Furthermore, the nano-reinforcing phase is added to the coating in the form of solid powder, or first prepared as a dispersion in an organic solvent and then added to the coating;

[0023] If the mass of the slurry masterbatch is m, the initial concentration of the nano-reinforcing phase is ω 0 , and the ratio of the organic solvent to the slurry masterbatch is x. When the target concentration of the nano-reinforcing phase is ω 纳米 , the amount of coating to be added is and control the range of x to be 0.5 to 4.

[0024] Furthermore, one or more of ultrasonic crushing, nano sand mill grinding, high-speed shearing, and mechanical stirring are used to mix the nano-reinforced phase into the coating.

[0025] Furthermore, the vacuum coating technology is one of magnetron sputtering, evaporation coating, and ion plating, and is prepared by a single machine or an automatic continuous coating production line.

[0026] The beneficial effects of the present invention are:

[0027] The present invention proposes an innovative high-weather-resistant UV nano coating and its preparation method, which effectively solves the shortcomings of existing coatings in terms of weather resistance, decorative effects and physical and mechanical properties. By cleverly combining UV curing technology, vacuum coating technology and nano-strengthening technology, the present invention constructs a new high-performance coating structure and achieves a comprehensive improvement in coating performance.

[0028] First of all, the design of the coating structure is very innovative. The UV primer layer provides good adhesion and flexibility, laying the foundation for the close combination of the coating and the substrate; the vacuum coating layer gives the coating a unique decorative effect, improving the aesthetics of the product; and the nano-reinforced UV topcoat layer, through the gradient change of the nano-reinforced phase concentration, not only enhances the coating's scratch resistance, wear resistance and corrosion resistance, but also maximizes the shielding effect of the nano-reinforced phase against ultraviolet rays, significantly improving the coating's weather resistance. This functionally integrated design enables the coating to exhibit excellent performance in many aspects.

[0029] Secondly, the performance improvement effect of the present invention is significant. The high concentration of nano-reinforced phase on the surface can fully reflect ultraviolet rays, effectively resist the erosion of the external environment, and at the same time improve the hardness and wear resistance of the coating. The lower concentration of nano-reinforced phase inside mainly absorbs ultraviolet rays and reduces the length of the scattering path, further enhancing the weather resistance of the coating. This gradient structure design not only improves the overall performance of the coating, but also achieves a perfect combination of high weather resistance and excellent protection.

[0030] In addition, the addition of organic solvents in the preparation of nano-modified UV coatings reduces the viscosity of the slurry masterbatch and increases the compatibility of nanoparticles in the diluent. Under the action of high-energy mixing, the nano-reinforced phase is evenly dispersed, avoiding the occurrence of agglomeration.

[0031] In addition, the process of the present invention has strong universality and has broad application prospects. The coating system can be applied to the surfaces of various substrates, such as metals, plastics, glass, etc., and can use a variety of nano-reinforcement phases, such as nano-SiO 2 、Nano-TiO 2etc., to meet the needs of different fields. At the same time, the flexibility of the preparation method also makes the coating system easy to promote and apply, providing a brand-new solution for the surface protection of high-end industrial products.

[0032] In summary, through the innovative coating structure design and the application of nano-strengthening technology, the present invention has successfully solved the deficiencies of traditional coatings in terms of weather resistance, decorative effect, and physical and mechanical properties, providing an effective solution for the stringent requirements of coating performance in modern industrial scenarios. This technical solution not only has remarkable innovation and practicality but also has broad application prospects and market value.

[0033] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0035] Figure 1 is a schematic flow chart of the preparation process of a preparation method for a high-weather-resistant UV nano-coating in the present invention;

[0036] Figure 2 is a schematic structural diagram of a high-weather-resistant UV nano-coating in Example 1;

[0037] Figure 3 is Figure 1 the SEM distribution diagram of the nano-strengthening phase in the UV topcoat layer 1 in

[0038] Figure 4 is Figure 1 the SEM distribution diagram of the nano-strengthening phase in the UV topcoat layer 2 in

[0039] Figure 5 is the distribution diagram of the thickness of each layer and the concentration of the nano-strengthening phase in the UV topcoat layer in Example 2. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0041] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams rather than actual pictures, and should not be construed as a limitation on the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which do not represent the dimensions of actual products; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0042] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as a limitation on the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0043] Embodiment 1

[0044] Please refer to Figures 1 to 4 , which is a highly weather-resistant UV nano-coating, including a UV topcoat layer, a vacuum coating layer, and a UV primer layer arranged in sequence from the surface to the inside. The raw materials of the UV coating (UV primer layer and UV topcoat layer) are epoxy resin systems. The UV primer layer is manually sprayed directly on the substrate, and the coating thickness is 20 μm; the vacuum coating layer is prepared by an evaporation coating machine to form a pure metal Al film, showing a silver-white luster, and the film thickness is 300 nm; the UV topcoat layer contains two layers, namely a UV topcoat layer 1 and a UV topcoat layer 2 arranged in sequence from the inside to the outside. The nano-strengthening phase is Al 2 O 3, due to its small particle size, it can transmit visible light, and its refractive index is close to that of the coating without causing scattering. After being added to the coating, it will not significantly reduce the gloss of the coating, and the whole still presents a silver-white color. Among them, the thickness of the UV topcoat layer 1 is 25 μm, the concentration of the nano-reinforcing phase is 10 wt.%, the thickness of the UV topcoat layer 2 is 3 μm, and the concentration of the reinforcing phase is 50 wt.%.

[0045] Please refer to Figure 1 , which details the preparation process of the UV topcoat layer:

[0046] First, 200 g of nano-Al 2 O 3 is added to 200 g of the coating to form a slurry masterbatch with ω 0 of 50 wt.% and a total of 500 g. Then, 1600 g of methyl ethyl ketone (MEK) is added to the slurry masterbatch to form a diluent to increase fluidity and compatibility. Then, it is ground by a nano-sand mill for 60 min to mix it evenly. Subsequently, it is baked in a vacuum drying oven at 75 °C for 120 min to remove the solvent. The remaining slurry masterbatch is divided into two parts of 450 g and 50 g. According to the formula, 1800 g of epoxy resin UV coating needs to be added to 450 g of the slurry and then sprayed on the vacuum coating layer as the UV topcoat layer 1, while 50 g of the slurry is directly sprayed on the UV topcoat layer 1 without adding additional coating as the UV topcoat layer 2;

[0047] After spraying, it is baked at 70 °C for 8 min to volatilize the solvent in the UV coating. Finally, it is irradiated under a light intensity of 80 mW / cm 2 to accumulate an energy of 900 mJ / cm 2 to complete UV curing. This coating structure is as Figure 2 shown, where the distribution of the nano-reinforcing phase in the UV topcoat layer 1 and the UV topcoat layer 2 is as Figure 3 and Figure 4 shown.

[0048] At the same time, a varnish coating with a UV topcoat layer thickness of 28 μm was prepared as a control group, and a number of performance tests were carried out on the two groups of coatings.

[0049] Example 2

[0050] A highly weather-resistant UV nano-coating, including a UV primer layer, a vacuum coating layer, and a UV topcoat layer arranged in sequence from the inside to the outside. Among them, the raw materials of the UV coating (UV primer layer and UV topcoat layer) are polyurethane acrylate systems. The UV primer layer is sprayed by a production line robot and directly sprayed on the substrate, and the coating thickness is 10 μm; the vacuum coating layer is prepared by an automatic continuous magnetron sputtering coating system to deposit an AlN film, and its thickness is adjusted to 80 nm to obtain a thin film with a sapphire blue luster;

[0051] The UV topcoat layer consists of 4 layers in total. As Figure 5 shown, the concentration of the nano-reinforced phase in these 4 coating layers gradually decreases from the surface to the interior, being 20wt.%, 12wt.%, 8wt.% and 4wt.% respectively, and the corresponding coating thicknesses are 5, 15, 15 and 15 μm respectively;

[0052] Please refer to Figure 1 , and the coating preparation process is as follows:

[0053] Firstly, 400 g of nano-TiO2 is added to 600 g of coating (a polyurethane acrylate-based coating) to form a slurry masterbatch of 1000 g with ω 0 being 40wt.%. Then, 1000 g of ethyl acetate (EAC) is added to the slurry masterbatch to form a diluent to increase fluidity and compatibility. Then, it is ultrasonically mixed evenly for 30 min by a polyenergy ultrasonic crusher. Subsequently, it is baked in a vacuum drying oven at 70 °C for 60 min to remove the solvent. The remaining slurry masterbatch is divided into four portions of 300, 300, 300 and 100 g. According to the formula, 2700 g of coating is added to the first portion, 1200 g of coating is added to the second portion, 700 g of coating is added to the third portion, and 100 g of coating is added to the fourth portion, and they are sprayed in sequence by a robot. After spraying, it is baked at 60 °C for 6 min to volatilize the solvent in the UV coating. Finally, it is irradiated under a light intensity of 60 mW / cm 2 to accumulate an energy of 1400 mJ / cm 2 to complete UV curing.

[0054] Meanwhile, a varnish coating with a UV topcoat layer thickness of 50 μm is prepared as a control group, and a number of performance tests are carried out on the two groups of coatings.

[0055] Table 1 Comparison table of the performance of pure UV coatings and nano-reinforced UV coatings

[0056]

[0057] The results of various performance tests of the coating systems in the above respective embodiments are shown in Table 1, which can be used to evaluate the comprehensive performance of the coatings. All the above coatings have good adhesion. For the nano-reinforced UV coating with a gradient structure, compared with the corresponding pure UV coating, there are significant improvements in pencil hardness, resistance to CASS salt spray, resistance to boiling water performance and anti-photoaging performance, and there are also obvious advantages in yellowing resistance and color retention. It truly realizes the unity of high weather resistance, excellent decorative effect and good mechanical properties. This coating system has a wide application prospect in the field of exterior parts.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A highly weather-resistant UV nano coating, characterized in that: It includes a UV topcoat layer, a vacuum coating layer and a UV primer layer which are arranged in sequence from the outside to the inside; The UV topcoat layer is composed of at least two sub-UV topcoat layers, each of which contains a nano-reinforced phase, and the concentration of the nano-reinforced phase in the sub-UV topcoat layer decreases gradually from the surface to the inside.

2. The highly weather-resistant UV nano coating according to claim 1, characterized in that: The total thickness of the coating is 10-100 μm, the thickness of the UV primer layer is 5-40 μm, the thickness of the vacuum coating layer is 0.1-1 μm, the thickness of the UV topcoat layer is 5-60 μm, and the thickness of the sub-UV topcoat layer arranged on the outermost layer is 1-10 μm.

3. The highly weather-resistant UV nano coating according to claim 1, characterized in that: The nano-reinforced phase in the UV topcoat layer is one or more of nano-SiO2, nano-TiO2, nano-ZnO, nano-CeO2, nano-ZrO2, nano-Al2O3, nano-Fe2O3, carbon nanotubes and graphene, and the particle size of the nano-reinforced phase is in the range of 1 to 500 nm.

4. The highly weather-resistant UV nano coating according to claim 1, characterized in that: The nano-reinforced phase concentration of the sub-UV topcoat layer arranged on the outermost layer of the UV topcoat layer is 20-60wt.%, and the nano-reinforced phase concentration of the sub-UV topcoat layer arranged on the innermost layer is 0.5-20wt.%.

5. A method for preparing a highly weather-resistant UV nano coating, characterized in that: The following steps are involved: Step 1. Applying UV coating on a substrate to prepare a UV primer layer; Step 2. preparing a vacuum coating layer on the UV primer layer by using vacuum coating technology; Step 3. Coating at least two layers of nano-modified UV coatings with different nano-reinforced phase concentrations on the vacuum coating layer to prepare a UV topcoat layer, and controlling the nano-reinforced phase concentration of the UV topcoat layer to show a gradient change from the surface to the inside.

6. The method for preparing a highly weather-resistant UV nano coating according to claim 5, characterized in that: The nano-modified UV coating is prepared by a dilution evaporation production method, and the specific preparation steps are as follows: First, the nano-reinforced phase is added to the coating to form a slurry masterbatch, and then an organic solvent is added to form a diluent. After the diluent is evenly mixed, the organic solvent is evaporated. Finally, different amounts of coating are added in batches according to needs and stirred to obtain nano-modified UV coatings with different nano-reinforced phase concentrations.

7. The method for preparing a highly weather-resistant UV nano coating according to claim 6, characterized in that: The nano-reinforced phase is added to the coating in the form of solid powder, or is first prepared as a dispersion in an organic solvent and then added to the coating; If the mass of the slurry masterbatch is m, the initial concentration of the nano-reinforced phase is ω0, and the ratio of the organic solvent to the slurry masterbatch is x, when the target concentration of the nano-reinforced phase is ω 纳米 The amount of coating to be added is And the range of x is controlled to be 0.5-4.

8. The method for preparing a highly weather-resistant UV nano coating according to claim 6, characterized in that: One or more of ultrasonic wave crushing, nano sand mill grinding, high-speed shearing and mechanical stirring are used to mix the nano reinforcement phase into the coating.

9. The method for preparing a highly weather-resistant UV nano coating according to claim 5, characterized in that: The vacuum coating technology is one of magnetron sputtering, evaporation coating, and ion plating, and is prepared by a single machine or an automatic continuous coating production line.

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