Acrylic mirror panel for acoustic panel and manufacturing method thereof

Abstract

The application discloses an acrylic mirror panel for a sound panel, which comprises, from top to bottom, a varnish protection layer, an aluminum plating layer and an acrylic substrate layer, wherein the varnish protection layer is formed by a varnish spray curing process with components of acrylate resin, polyurethane acrylate resin and photoinitiator. A preparation method of the acrylic mirror panel for the sound panel comprises vacuum aluminum plating, varnish spraying and curing steps, and the panel has excellent wear resistance, adhesion and high reflectivity.

Description

Technical Field

[0001] This application relates to the field of surface treatment technology, and more specifically, it relates to an acrylic mirror panel for an audio panel and a method for preparing the same. Background Technology

[0002] Acrylic mirror panels are widely used in the manufacture of high-end audio panels due to their excellent light transmittance, aesthetics, and processing performance. To enhance the decorative effect, vacuum aluminum plating is typically performed on the back of the acrylic substrate to form a highly reflective metallic mirror layer. However, the aluminum plating layer is chemically reactive and soft, making it highly susceptible to damage from scratches, oxidation, or humid environments, leading to a decline in its optical performance. In related technologies, a protective film made of photoresist is usually applied to the aluminum plating layer for protection.

[0003] Regarding the aforementioned technologies, the photoresist film itself suffers from quality problems such as white marks, pitting, and "ghosting" that are difficult to eliminate. Furthermore, during the lamination process, dust, improper handling, or film defects can easily lead to bubbles, wrinkles, impurities, or poor adhesion, resulting in an overall defect rate exceeding 30%, causing significant waste of materials and time. Moreover, the interfacial adhesion between the photoresist film and the aluminized layer is limited, making it prone to peeling under long-term use or in environments with changing temperature and humidity, affecting product lifespan and reliability.

[0004] Furthermore, the coating structure has obvious physical interfaces, which affects the optical consistency and overall aesthetics of the product, making it difficult to meet the stringent requirements of high-end audio equipment for appearance quality. Summary of the Invention

[0005] To address the problems in related technologies where the use of a photoresist protective layer to protect the aluminum plating layer on an acrylic substrate results in low yield, poor lifespan and reliability, and difficulty in meeting the stringent appearance quality requirements of high-end audio equipment, this application provides an acrylic mirror panel for audio panels and its preparation method.

[0006] In a first aspect, this application provides an acrylic mirror panel for an audio panel, employing the following technical solution:

[0007] An acrylic mirror panel for an audio panel includes, from top to bottom, a varnish protective layer, an aluminum plating layer, and an acrylic substrate layer. The varnish protective layer is formed by coating the aluminum plating layer with varnish, and the varnish contains the following components in parts by weight:

[0008] 40-60 parts of acrylate resin;

[0009] 20-30 parts of polyurethane acrylate resin;

[0010] 10-20 parts of reactive diluent;

[0011] 3-8 parts of photoinitiator;

[0012] Leveling agent 0.5-2 parts;

[0013] 0.3-1 part defoamer;

[0014] Adhesion promoter 1-5 parts.

[0015] By adopting the above technical solution, the protective layer formed by the formulation of varnish mainly composed of acrylic resin and polyurethane acrylic resin avoids the appearance defects such as white marks, pitting, and "ghosting" commonly found in traditional varnish films, significantly reducing the appearance defect rate. Simultaneously, the protective layer and the aluminized layer are seamlessly covered, eliminating the physical interface and significantly improving the optical uniformity and overall aesthetics of the product, meeting the stringent appearance requirements of high-end audio equipment. Furthermore, the adhesion promoters and other components in the formulation enhance the interfacial bonding between the protective layer and the aluminized layer, effectively overcoming the problem of easy peeling of traditional coatings and improving the long-term reliability of the product under varying temperature and humidity conditions.

[0016] Preferably, the method for preparing the varnish includes the following steps:

[0017] Step S1: Place the acrylate resin, polyurethane acrylate resin and reactive diluent into a reaction vessel and mix them, stirring at 40-60°C for 20-40 minutes.

[0018] Step S2: Add the photoinitiator, leveling agent, defoamer and adhesion promoter to the reaction vessel, and continue stirring for 10-20 minutes;

[0019] Step S3: After vacuum degassing, a uniform varnish is obtained.

[0020] By adopting the above technical solution, the step-by-step mixing and temperature-controlled stirring process ensures that the components are fully dispersed and compatible, improving the uniformity and stability of the varnish. This ensures the consistency of the final protective layer in terms of film quality, adhesion performance and appearance, which is beneficial to quality control in industrial production.

[0021] Preferably, in the varnish, the reactive diluent is at least one of dipropylene glycol diacrylate, trimethylolpropane triacrylate, or 1,6-hexanediol diacrylate.

[0022] By adopting the above technical solution, acrylate diluents have moderate reactivity and dilution capacity, which can optimize the viscosity of varnish, improve the leveling properties of curtain coating, and participate in curing crosslinking, which helps to form a dense cured film with a balance of hardness and toughness, and further avoid coating defects such as pitting and flow marks.

[0023] Preferably, the photoinitiator is at least one of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, or 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

[0024] By adopting the above technical solutions, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, or 2,4,6-trimethylbenzoyl diphenylphosphine oxide, as photoinitiators, have the characteristics of efficient absorption of ultraviolet light and suitable initiation rate. This ensures that the varnish is cured quickly and thoroughly during the UV curing stage, forming a smooth and scratch-resistant protective layer, while reducing the problem of coating stickiness or decreased durability caused by incomplete curing.

[0025] Preferably, the thickness of the varnish protective layer is 10-20 μm.

[0026] By adopting the above technical solution, the thickness of the varnish protective layer is limited to 10-20μm. This range ensures sufficient protection while maximizing the metallic texture and optical reflection effect of the aluminum plating layer. Too thin a layer can lead to insufficient protection, while too thick a layer can affect the uniformity of light transmission and increase costs. This thickness range achieves the best balance between protection and aesthetics.

[0027] Preferably, the thickness of the aluminum plating layer is 20-40 μm.

[0028] By adopting the above technical solution, the thickness of the aluminum plating layer is 20-40μm. This thickness range can ensure that the aluminum layer has high reflectivity and excellent metallic mirror effect, while avoiding the increase of internal stress or the decrease of adhesion caused by excessive thickness, thus providing a stable and flat substrate for the varnish protective layer.

[0029] Secondly, this application provides a method for manufacturing an acrylic mirror panel for an audio panel, employing the following technical solution:

[0030] A method for preparing an acrylic mirror panel for use in audio panels includes the following steps:

[0031] Step A1: Prepare the acrylic substrate by putting the raw material of the substrate into an extruder for extrusion molding, cutting the molded substrate into the required size, and grinding, polishing and cleaning the cut substrate.

[0032] Step A2: Vacuum aluminum plating. The acrylic substrate obtained in step A1 is placed into a vacuum coating machine for vacuum evaporation to obtain an aluminum plating layer. The vacuum degree in the vacuum coating machine is 5.0 × 10⁻⁶. -3 Pa, the coating material is aluminum wire with a purity of ≥99.9%, the evaporation current is 150-250 A, the substrate temperature is 40-60℃, and the coating time is 90-180 seconds;

[0033] Step A3: Apply varnish. Transfer the aluminized sheet to the coating machine. The coating used in the coating machine is varnish. The baking temperature of the coating machine is 16-18℃. The density of the varnish is 1.1g / cm³ to 1.2g / cm³. The conveying speed of the coating machine conveyor belt is 3-5 m / min.

[0034] Step A4: Curing and molding. After the varnish is applied, the board is placed into the infrared curing oven and the UV curing oven in sequence for baking and curing. The infrared baking temperature is 45-55℃, and the UV curing temperature is 65-75℃. By adopting the above technical solutions, after extrusion molding and cutting, grinding, polishing and cleaning are performed to ensure that the surface of the acrylic substrate achieves a high degree of flatness and cleanliness, reducing the hidden dangers such as uneven aluminum plating, pinholes or weak adhesion caused by substrate surface defects. Setting a high vacuum, using high-purity aluminum wire, and controlling appropriate evaporation current and substrate temperature ensures that aluminum atoms are densely and uniformly deposited on the substrate surface, forming a fine-grained, high-purity, and strongly adhesive aluminum plating layer. Under low temperature and specific viscosity conditions, spray coating is performed, which realizes that the varnish flows evenly and smoothly on the vertical aluminum plating layer surface, naturally forming a seamless, non-physical interface continuous liquid film. Compared with traditional lamination, it completely avoids problems such as bubbles, wrinkles, impurities and white marks caused by uneven bonding pressure, defects in the film material itself or dust entrainment, reducing the appearance defect rate from more than 30% to an extremely low level. Gentle preheating through infrared baking promotes further leveling of the varnish coating and removes residual micro-bubbles, while avoiding deformation of the aluminum plating layer or substrate caused by sudden high temperature impact. UV curing is then performed, which causes the coating to undergo a rapid cross-linking reaction under the action of a photoinitiator, forming a solid protective layer with high hardness, strong wear resistance, and tight bonding with the aluminum plating layer through chemical bonds and physical anchoring. The step-by-step curing method ensures low internal stress and maximized adhesion of the coating.

[0035] In summary, this application includes at least one of the following beneficial technical effects:

[0036] 1. In the structure of the acrylic mirror panel, a protective layer formed by a varnish formulation primarily composed of acrylate resin and polyurethane acrylate resin avoids common appearance defects such as white marks, pitting, and "ghosting" found in traditional varnish films, significantly reducing the appearance defect rate. Simultaneously, this protective layer seamlessly overlaps with the aluminized layer, eliminating the physical interface and significantly improving the product's optical uniformity and overall aesthetics, meeting the stringent appearance requirements of high-end audio equipment. Furthermore, adhesion promoters and other components in the formulation enhance the interfacial bonding between the protective layer and the aluminized layer, effectively overcoming the problem of easy peeling in traditional coatings and improving the long-term reliability of the product under varying temperature and humidity conditions.

[0037] 2. In the preparation of acrylic mirror panels, after extrusion molding and cutting, grinding, polishing, and cleaning are performed to ensure a high degree of flatness and cleanliness on the acrylic substrate surface. This reduces potential problems such as uneven aluminum plating, pinholes, or weak adhesion caused by substrate surface defects. Setting a high vacuum, using high-purity aluminum wire, and controlling appropriate evaporation current and substrate temperature ensures dense and uniform deposition of aluminum atoms on the substrate surface, forming a fine-grained, high-purity, and strongly adhesive aluminum plating layer, under low temperature and specific viscosity conditions. The coating process involves spraying to achieve a uniform and stable flow of the varnish on the vertical aluminum plating surface, naturally forming a seamless, continuous liquid film without physical interfaces. Compared to traditional lamination, this completely avoids problems such as bubbles, wrinkles, impurities, and white marks caused by uneven bonding pressure, defects in the film material itself, or dust trapping, reducing the appearance defect rate from over 30% to an extremely low level. Gentle preheating via infrared baking further promotes the leveling of the varnish coating and removes residual micro-bubbles, while preventing deformation of the aluminum plating or substrate due to sudden high-temperature impact. Subsequent UV curing, under the action of a photoinitiator, causes the coating to rapidly undergo a cross-linking reaction, forming a solid protective layer with high hardness, strong wear resistance, and a tight bond with the aluminum plating through chemical bonds and physical anchoring. This step-by-step curing method ensures low internal stress, maximized adhesion, and complete curing, significantly improving the long-term durability of the product in complex environments. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of an acrylic mirror panel for an audio panel according to this embodiment.

[0039] Reference numerals: 1. First protective film layer; 2. Varnish protective layer; 3. Aluminum plating layer; 4. Acrylic substrate layer; 5. Second protective film layer; Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] Reference Figure 1An acrylic mirror panel for use in audio panels includes, from top to bottom, a first protective film layer 1, a varnish protective layer 2, an aluminum plating layer 3, an acrylic substrate layer 4, and a second protective film layer 5. Both the first protective film layer 1 and the second protective film layer 5 are peelable films providing protection for the acrylic mirror panel during transportation. The varnish protective layer 2 has a thickness of 15 μm, and the aluminum plating layer 3 has a thickness of 30 μm. The varnish protective layer 2 is formed by coating the aluminum plating layer 3 with varnish, which contains the following components in parts by weight:

[0042] 40-60 parts of acrylate resin;

[0043] 20-30 parts of polyurethane acrylate resin;

[0044] 10-20 parts of reactive diluent;

[0045] 3-8 parts of photoinitiator;

[0046] Leveling agent 0.5-2 parts;

[0047] 0.3-1 part defoamer;

[0048] Adhesion promoter 1-5 parts.

[0049] The preparation of varnish is as follows:

[0050] Preparation Example 1 includes the following steps:

[0051] Step S1: Mix 500g of acrylate resin, 250g of polyurethane acrylate resin, and

[0052] 150g of reactive diluent was placed in a reaction vessel and mixed, and stirred at 45℃ for 30 minutes;

[0053] Step S2: Add 50g of photoinitiator, 10g of leveling agent, 5g of defoamer and 30g of adhesion promoter to the reaction vessel, and continue stirring for 15 minutes;

[0054] Step S3: After vacuum degassing, a uniform varnish is obtained.

[0055] The reactive diluent is at least one of dipropylene glycol diacrylate, trimethylolpropane triacrylate, or 1,6-hexanediol diacrylate; in this preparation example, dipropylene glycol diacrylate is used. The photoinitiator is at least one of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, or 2,4,6-trimethylbenzoyl diphenylphosphine oxide; in this preparation example, 2-hydroxy-2-methyl-1-phenylpropanone is used. The adhesion promoter is an organosilicon coupling agent.

[0056] To verify the effect of different formulations, this application also provides preparation examples 2-3 and preparation comparative examples 1-2. The differences between preparation examples 2-3 and preparation comparative examples 1-2 and preparation example 1 are shown in Table 1 below.

[0057] Table 1. Material types, amounts, and process conditions for preparation examples 1-3 and comparative examples 1-2.

[0058] Acrylic resin dosage / g 500 450 550 700 500 Polyurethane acrylate resin dosage / g 250 280 220 / 250 Dipropylene glycol diacrylate dosage / g 150 180 120 200 150 Step S1 Stirring temperature / ℃ 40 40 40 40 40 Step S1 Stirring time / minute 30 30 30 30 30 Dosage of 2-hydroxy-2-methyl-1-phenylpropanone / g 50 40 60 50 50 Organosilicon coupling agent dosage / g 30 32 28 30 / Leveling agent dosage / g 10 12 8 10 10 Defoamer dosage / g 5 6 4 5 5 Step S2 Stirring time / minute 15 15 15 15 15

[0059] Example 1

[0060] This application provides a method for manufacturing an acrylic mirror panel for an audio panel, using the following technical solution:

[0061] A method for preparing an acrylic mirror panel for use in audio panels includes the following steps:

[0062] Step A1: Prepare an acrylic substrate. Place the raw material of the substrate into an extruder for extrusion molding, cut the molded substrate into the required size, and grind, polish and clean the cut substrate to obtain acrylic substrate layer 4.

[0063] Step A2: Vacuum aluminum plating. The acrylic substrate obtained in step A1 is placed into a vacuum coating machine for vacuum evaporation to obtain an aluminum plating layer. The vacuum degree in the vacuum coating machine is 5.0 × 10⁻⁶. -3 Pa, the coating material is aluminum wire with a purity of ≥99.9%, the evaporation current is 200 A, the substrate temperature is 50℃, the coating time is 150 seconds, and an aluminum coating layer 3 is obtained;

[0064] Step A3: Apply varnish. The aluminized sheet is transferred to the coating machine. The coating material used in the coating machine is the varnish prepared in Preparation Example 1. The baking temperature of the coating machine is 17°C, the density of the varnish is 1.2 g / cm³, and the conveying speed of the coating machine conveyor belt is 4 m / min.

[0065] Step A4: Curing and molding. The coated board is placed into an infrared curing oven and a UV curing oven in sequence for baking and curing. The infrared baking temperature is 50℃ and the UV curing temperature is 70℃. Both the infrared curing oven and the UV curing oven are curing ovens with conveyor lines, and the conveying speed is 4m / min. The board is conveyed for 0.5 minutes at this speed to obtain the varnish protective layer 2.

[0066] Example 2

[0067] The difference between Example 2 and Example 1 is that the varnish in step A3 is the varnish prepared in preparation 2.

[0068] Example 3

[0069] The difference between Example 3 and Example 1 is that the varnish in step A3 is the varnish prepared in preparation 3.

[0070] Example 4

[0071] The difference between Example 2 and Example 1 is that the varnish in step A3 is the varnish prepared in Comparative Example 1.

[0072] Example 5

[0073] The difference between Example 2 and Example 1 is that the varnish in step A3 is the varnish prepared in Comparative Example 2.

[0074] Performance testing

[0075] The acrylic mirror panels prepared according to the preparation methods of Examples 1-5 above were subjected to abrasion resistance test, adhesion test, hardness test, and reflectivity test.

[0076] Abrasion resistance test:

[0077] The abrasion resistance tester from Guangdong Yuelian Instruments Co., Ltd. was used. The test was conducted under the following conditions: a 250g load, friction with lint-free paper, a speed of 30-50T, and 10 cycles. Visible wear on the coating (whether the aluminum plating layer was exposed) was recorded.

[0078] Wear conditions in Examples 1-5:

[0079] Example 1: Minor scratches, no exposed aluminum plating layer;

[0080] Example 2: Minor scratches, no exposed aluminum plating layer;

[0081] Example 3: Slight scratches, no exposed aluminum plating layer;

[0082] Example 4: Exposed aluminum plating layer;

[0083] Example 5: Minor scratches, no exposed aluminum plating layer;

[0084] Examples 1-3 all exhibited good abrasion resistance, thanks to the use of acrylate resin and polyurethane acrylate resin in the varnish, which formed a dense, hard-tough bond. Example 4, lacking a flexible polyurethane acrylate resin, showed increased coating brittleness and a significant decrease in abrasion resistance.

[0085] Adhesion test:

[0086] The cross-cut test was conducted using 3M 610 tape. The coating peeling grade was evaluated according to ASTM D3359 standard, with 0B being the worst and 5B being the best.

[0087] Example 1: 5B

[0088] Example 2: 5B

[0089] Example 3: 5B

[0090] Example 4: 3B

[0091] Example 5: 1B

[0092] All Examples 1-3 achieved the highest 5B rating, indicating an extremely strong bond between the varnish protective layer and the aluminized layer. This is attributed to the effective action of the adhesion promoter in the formulation and the seamless interface formed by the spray coating process. Example 4 experienced decreased adhesion due to high internal stress caused by an unbalanced resin system. Example 5, lacking an adhesion promoter, suffered from severely insufficient interfacial bonding, resulting in almost complete peeling.

[0093] Reflectivity test:

[0094] The average specular reflectance of the sample in the visible light wavelength range of 380-780 nm was measured using a spectrophotometer.

[0095] Reflectivity:

[0096] Example 1: 89.5%

[0097] Example 2: 89.0%

[0098] Example 3: 88.8%

[0099] Example 4: 85.2%

[0100] Example 5: 87.5%

[0101] The reflectivity of samples in Examples 1-3 was close to 90%, and the metallic texture of the aluminum plating layer was clear. This was due to the high transparency and smoothness of the varnish protective layer, as well as its seamless bonding with the aluminum plating layer, which minimized light scattering. In Example 4, the reflectivity decreased due to potential microscopic inhomogeneities or internal defects in the coating. Although the initial reflectivity of Example 5 was acceptable, its poor adhesion meant that long-term reliability could not be guaranteed, and the reflectivity would rapidly decrease as the coating deteriorated.

[0102] Hardness test:

[0103] Hardness tests were conducted on the product using an electric pencil hardness tester. Pencils of varying hardness (5B, 6B, 7B) were used, with 5B being the hardest. The pencil was fixed to the hardness tester with a load of 250g and pushed at approximately 1cm / s to scratch the coating surface, leaving a 10mm mark. The same spot was scratched three times, and the scratch pattern was observed. The pencil hardness used when the coating was scratched was recorded.

[0104] Example 1: 5B

[0105] Example 2: 5B

[0106] Example 3: 5B

[0107] Example 4: 5B

[0108] Example 5: 7B

[0109] The varnish protective layer in Examples 1-3 all had a hardness of 5B, which is relatively hard. This is attributed to the dense cross-linked network formed by the acrylic resin and polyurethane acrylic resin. Example 7 had the worst hardness of 7B, which was caused by the lack of an adhesion promoter, resulting in a loose resin system structure.

[0110] In summary, this application utilizes a varnish made primarily of acrylic resin and polyurethane acrylic resin, along with key additives such as adhesion promoters, and employs a coating and curing process to produce a high-performance acrylic mirror panel for audio equipment. This panel not only eliminates the appearance defects associated with traditional lamination processes, reducing the overall defect rate to a low level, but also exhibits superior adhesion between its varnish protective layer 2 and the aluminum plating layer 3. This results in excellent performance in terms of wear resistance, aging resistance, hardness, and optical stability, meeting the stringent requirements of high-end audio equipment for appearance, quality, and reliability.

[0111] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An acrylic mirror panel for use in audio panels, characterized in that: It includes, from top to bottom, a varnish protective layer, an aluminum plating layer, and an acrylic substrate layer. The varnish protective layer is formed by coating the aluminum plating layer with varnish, and the varnish contains the following components in parts by weight: 40-60 parts of acrylate resin; 30-60 parts of polyurethane acrylate resin; 10-20 parts of reactive diluent; 3-8 parts of photoinitiator; Leveling agent 0.5-2 parts; 0.3-1 part defoamer; Adhesion promoter 1-5 parts; The preparation method of the varnish includes the following steps: Step S1: Place the acrylate resin, polyurethane acrylate resin and reactive diluent into a reaction vessel and mix them, stirring at 40-60°C for 20-40 minutes. Step S2: Add the photoinitiator, leveling agent, defoamer and adhesion promoter to the reaction vessel, and continue stirring for 10-20 minutes; Step S3: After vacuum degassing, a uniform varnish is obtained; In the varnish, the reactive diluent is at least one of dipropylene glycol diacrylate, trimethylolpropane triacrylate, or 1,6-hexanediol diacrylate. The photoinitiator is at least one of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, or 2,4,6-trimethylbenzoyl diphenylphosphine oxide; The thickness of the varnish protective layer is 10-20 μm; The thickness of the aluminum plating layer is 20-40 μm; The method for preparing an acrylic mirror panel for use in an audio panel includes the following steps: Step A1: Prepare the acrylic substrate by putting the raw material of the substrate into an extruder for extrusion molding, cutting the molded substrate into the required size, and grinding, polishing and cleaning the cut substrate. Step A2: Vacuum aluminum plating. The acrylic substrate obtained in step A1 is placed into a vacuum coating machine for vacuum evaporation to obtain an aluminum plating layer. The vacuum degree in the vacuum coating machine is 5.0 × 10⁻⁶. -3 Pa, the coating material is aluminum wire with a purity of ≥99.9%, the evaporation current is 150-250 A, the substrate temperature is 40-60℃, and the coating time is 90-180 seconds; Step A3: Apply varnish. Transfer the aluminized sheet to the coating machine. The coating used in the coating machine is varnish. The baking temperature of the coating machine is 16-18℃. The density of the varnish is 1.1g / cm³ to 1.2g / cm³. The conveying speed of the coating machine conveyor belt is 3-5m / min. Step A4: Curing and molding. After the varnish is applied, the board is placed into the infrared curing oven and the UV curing oven in sequence for baking and curing. The infrared baking temperature is 45-55℃, and the UV curing temperature is 65-75℃.

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