METHOD AND PROCESS OF VACUUM PLACING FOR BONDING PLASTICS

Abstract

METHOD AND PROCESS FOR VACUUM PLATING FOR BONDING PLASTICS The invention provides a method and process for vacuum plating for bonding plastics. By uniformly applying a semi-transparent primer to the back of the plastic substrate, the invention improves adhesion and cohesion between the vacuum plating and the substrate, preventing the plating from detaching or puckering during prolonged use. By using an opaque black paint as a chrome- or aluminized-type vacuum plating, the invention effectively prevents light leakage. The interposition of the semi-transparent primer between the plastic substrate and the vacuum plating enhances adhesion and cohesion, as well as resistance to hot and humid environments.Adding a protective varnish to the back increases the reliability of the bond while eliminating traces of the glue layer. Figure to be published with the abbreviation: Figure 1.

Description

Title of the invention: METHOD AND PROCESS FOR VACUUM PLATING FOR BONDING PLASTICS FIELD OF THE INVENTION

[0001] The invention relates to the technical field of automotive parts processing, and more particularly, relates to a process and method of vacuum plating for bonding plastics. STATE OF THE ART

[0002] With the development of the automotive industry, the colors of car interiors are also becoming increasingly varied. Due to environmental requirements, plating processes that are significantly harmful to the environment are being phased out and replaced by vacuum plating. Vacuum plating, also known as physical vapor deposition (PVD), is a process that involves vaporizing the surface of a source material (solid or liquid) under vacuum into gaseous atoms or molecules, or partially ionizing it into ions, while simultaneously depositing, via a low-pressure gas (or plasma) process, a film or coating with a specific function onto the substrate surface. Modifying the source material can adjust the color of the film or coating, resulting in a wider and richer range of colors.Furthermore, compared to traditional plating processes, this process is more environmentally friendly and non-polluting.

[0003] In the manufacture of automotive electronic components, vacuum plating is often used for surface treatment of parts so that they can serve as decorative pieces bonded to the surface of automotive electronic components. However, the existing vacuum plating process presents significant problems.

[0004] The vacuum plating process described in patent CN116949393A exhibits several defects during actual use after bonding manufactured parts to the surface of electronic components. Firstly, after prolonged use or when the vehicle is exposed to intense heat, difficult-to-remove adhesive residue appears on the surface of the parts, severely affecting the product's aesthetic quality. Secondly, in this method, the adhesion and cohesion between the coating and the substrate are insufficient, making resistance to high-temperature and high-humidity environments difficult. This can easily lead to delamination or damage of the coating, reducing the lifespan and reliability of the parts.

[0005] Furthermore, existing processes are not very effective at improving the wear resistance of the surface of the parts, and do not effectively protect the substrate. At the same time, their performance in terms of visual effect is also insufficient, which does not meet the high requirements of automotive electronic components regarding decorative appearance.

[0006] In conclusion, current vacuum plating processes have many drawbacks with regard to adhesive residue, coating adhesion and cohesion, substrate protection, wear resistance, display effect, etc. It is therefore necessary to develop new and improved vacuum plating processes and methods for bonding plastics to overcome these problems. Accordingly, we present improvements and propose a vacuum plating process for bonding plastics. Description of the invention

[0007] The objective of the invention is to address the problems raised by the prior art. To achieve the objective of the invention mentioned above, the invention proposes a method for manufacturing a substrate comprising a front face and a back face onto which a coating is applied by vacuum plating, characterized in that it comprises the following steps:

[0008] SI. Preparation of materials:

[0009] - select a transparent plastic substrate and a protective varnish intended to be applied to the front face of the substrate;

[0010] - prepare a semi-transparent primer;

[0011] - select a coating material for vacuum plating;

[0012] - prepare a finishing varnish and a protective varnish intended to be applied to the rear face of the substrate;

[0013] S2. Application of the protective varnish to the front face of the substrate:

[0014] - apply the protective varnish by spraying or brushing onto the front face of the substrate;

[0015] - use ultraviolet equipment on the front side to then harden the varnish applied to the front surface, in order to form a high-hardness, high-gloss varnish film;

[0016] S3. Application of the semi-transparent primer:

[0017] - apply the semi-transparent primer evenly to the back face of the substrate;

[0018] - proceed with high-temperature drying of the rear side of the coated substrate semi-transparent primer;

[0019] S4. Vacuum plating:

[0020] - place the substrate coated with the semi-transparent primer in equipment vacuum plating for vacuum plating treatment on semi-transparent primer;

[0021] S5. Application of the finishing varnish:

[0022] - after vacuum plating, apply the finishing varnish by spraying or brushing on the external surface of the veneer;

[0023] S6. Application of the protective varnish to the rear side:

[0024] - apply the protective varnish to the back side of the outer surface of the varnish finishing.

[0025] The term "semi-transparent" in describing the primer means that it allows 30% to 65% of light to pass through it, according to ISO 13468-2 "Plastics - Determination of the total luminous flux transmission factor of transparent materials. Part 2: Double beam instrument".

[0026] According to a particular feature of the invention, in step SI, said transparent plastic material substrate is an acrylic plastic material substrate, such as PMMA, or a polycarbonate (PC) substrate.

[0027] According to a particular feature of the invention, in step S2, said front-side protective varnish is a UV varnish with a thickness of 10 to 50 µm or said front-side protective varnish is a varnish crosslinked by ultraviolet radiation, the raw material of which is an epoxy resin.

[0028] According to a particular feature of the invention, at step S3, said semi-transparent primer has a thickness of 10 to 60 sqm.

[0029] According to a particular feature of the invention, in step S4, said vacuum plating coating has a thickness of 0.1 to 15 sqm, said coating then being a coloured paint with a chrome layer or a coloured paint with an aluminized layer or said vacuum plating coating has a thickness of 20 to 50 sqm, said coating then being an opaque black paint.

[0030] According to a particular feature of the invention, in step S6, said protective varnish on the back side is a UV varnish or a PU varnish with a thickness of 10 to 50 µm, said varnish being film-forming.

[0031] According to a particular feature of the invention, after step S5, the following additional steps are carried out:

[0032] S5i. Laser engraving of symbols on the rear side: - Laser engrave required display symbols by removing the semi-transparent primer, vacuum plating coating and finishing varnish, the color of the symbols being that of the substrate; S52:: Ink printing:

[0033] Print a layer of translucent ink on the symbols, the color of the ink being determined according to the required display of the symbols;

[0034] the rear-side protective varnish of step S6 being then applied to the external surfaces of the finishing varnish and the printed ink; and by the fact that after step S6,

[0035] an LED light source is disposed behind the rear-side protective varnish; the LED light passes through the rear-side protective varnish and the printed ink, then through the substrate and the front-side protective varnish to be visible.

[0036] According to a particular feature of the invention, in step S5i, the specific steps of laser engraving the symbols are as follows:

[0037] al: Prepare the laser engraving equipment; fix the substrate already treated with the semi-transparent primer, the vacuum plating coating and the finishing varnish on the work table of the laser engraving equipment;

[0038] bl: Set the laser engraving parameters, which include: the laser power configured between 50 and 60 W, the engraving speed between 0 and 85 mm / min, the positioning repetition accuracy: + 0.1 mm;

[0039] cl: Start the laser engraving equipment and begin the engraving operation; the laser beam engraves, according to the predefined graphic data, the semi-transparent primer, the vacuum plating coating and the finishing varnish, in order to reveal the required symbols;

[0040] dl: After engraving, check the quality of the symbols, the color of which must be the transparent color of the substrate;

[0041] el: Clean the engraved part to remove debris and impurities generated during engraving.

[0042] According to a particular feature of the invention, in step S52, the specific steps of said ink printing are as follows:

[0043] Step a2: Prepare the ink according to the symbol display requirements, place the part on which the symbols have been laser engraved onto the printing equipment, and then use this equipment to print ink onto the symbols;

[0044] Step b2: Adjust the parameters of the printing equipment, which include: printing pressure, speed, and ink flow control, with the printing pressure set between 10 and 30 N / cm2, the printing speed set between 100 and 500 mm / s, and the ink flow set between 0.5 and 2 g / m2;

[0045] Step c2: The thickness of the printed ink layer is between 1 and 20 sqm; the ink color is selected for printing according to the required display of the symbols.

[0046] According to a particular feature of the invention, after step S6, an LED light source with a diameter of 2 to 6 mm and a power of 0.2 to 1.6 W is arranged behind the protective varnish on the rear side.

[0047] In other words, the invention relates to a vacuum plating process for bonding plastics, which comprises the following steps: SI. Material preparation:

[0048] - select a transparent plastic substrate and a protective varnish on the front side;

[0049] - prepare a semi-transparent primer;

[0050] - select the coating material for vacuum plating;

[0051] - prepare a finishing varnish and a protective varnish for the back side.

[0052] S2. Application of the protective varnish to the front side:

[0053] - apply by spraying or brushing onto the front face of the plastic substrate;

[0054] - use ultraviolet equipment to cure the protective varnish on the front side applied, in order to form a high-hardness, high-gloss varnish film.

[0055] S3. Application of the semi-transparent primer:

[0056] - apply the semi-transparent primer evenly to the back face of the substrate plastic;

[0057] - proceed to high-temperature drying of the rear face of the coated plastic substrate semi-transparent primer.

[0058] S4. Vacuum plating:

[0059] - place the substrate coated with the semi-transparent primer in a piece of equipment vacuum plating for vacuum plating treatment;

[0060] S5. Application of the finishing varnish:

[0061] - after vacuum plating, apply the finishing varnish by spraying or coating on the external surface;

[0062] S6. Application of the protective varnish to the rear side:

[0063] - apply the protective varnish to the back side of the external surfaces of the varnish finishing.

[0064] According to a preferred embodiment of the invention, in step SI, Material preparation: said plastic substrate is a transparent plastic substrate, said transparent plastic substrate comprises a PMMA (acrylic) substrate and a PC (polycarbonate) substrate.

[0065] According to a preferred embodiment of the invention, in step S2, Application of the protective varnish on the front side: said protective varnish on the front side is a UV varnish with a thickness of 10 to 50 µm; it is a varnish cross-linked by ultraviolet radiation, the raw material of which is an epoxy resin; it has high hardness and gloss, and is intended to protect the substrate as well as to improve the wear resistance of the surface of the parts.

[0066] According to a preferred embodiment of the invention, in step S3, Application of the semi-transparent primer: said semi-transparent base coat has a thickness of 10 to 60 µm, it is intended to strengthen the adhesion and cohesion between the coating and the vacuum plating substrate, in order to withstand high temperature and high humidity environments.

[0067] According to a preferred embodiment of the invention, in step S4, said vacuum plating coating has a thickness of 0.1 to 15 pm, said coating is a colored paint with a chrome layer or a colored paint with an aluminized layer, said vacuum plating coating has a thickness of 20 to 50 pm, said coating is an opaque black paint to prevent light leakage.

[0068] According to a preferred embodiment of the invention, in step S6, Application of the protective varnish on the back side: said protective varnish on the back side is a UV varnish or a PU varnish with a thickness of 10 to 50 µm, which forms a film naturally. The varnish film, relatively thin and not very hard, exhibits exceptional adhesion. Its gloss is uniform, without excessive brightness, which provides an excellent visual effect. Furthermore, it improves the reliability of the bond after application and eliminates visible adhesive residue caused by high temperature and humidity environments.

[0069] The invention also relates to a vacuum plating treatment method for bonding plastics, characterized in that it comprises the following steps:

[0070] Step 1: Apply a protective varnish to the front side of the plastic substrate by spraying or brushing; then, use ultraviolet equipment to cure said varnish, in order to form a high-hardness, high-gloss varnish film;

[0071] Step 2: Apply the semi-transparent primer evenly to the back face of the plastic substrate; then, proceed to dry the back face of the plastic substrate coated with the semi-transparent primer at high temperature.

[0072] Step 3: Place the substrate coated with the semi-transparent primer into a vacuum plating equipment for vacuum plating treatment, the thickness of the plating coating being between 0.1 pm and 15 pm;

[0073] Step 4: After vacuum plating, apply the finishing varnish by spraying or brushing onto the external surface;

[0074] Step 5: Laser engraving of symbols: Laser engrave the required display symbols by removing the semi-transparent primer, vacuum plating coating and finishing varnish, the color of the symbols being that of the plastic substrate;

[0075] Step 6: Printing the ink: Print a layer of translucent ink over the symbols, the color of the ink being determined according to the required display of the symbols;

[0076] Step 7: Apply a protective varnish to the front side of the external surfaces of the finishing varnish and the printed ink;

[0077] Step 8: An LED light source is arranged behind the back side of the protective varnish; the LED light passes through the back side of the protective varnish and the printed ink, then through the plastic substrate and the back side of the protective varnish to be visible.

[0078] According to a preferred embodiment of the invention, in step 5, Laser engraving of symbols, the specific steps are as follows:

[0079] Step 51: Prepare the laser engraving equipment; fix the part already treated with the semi-transparent primer, vacuum plating coating and finishing varnish on the work table of the laser engraving equipment; ensuring that the part is stable and positioned accurately; import the graphic data corresponding to the symbols to be displayed into the control system of the laser engraving equipment according to the required design.

[0080] Step 52: Set the laser engraving parameters, which include: laser power configured between 50 and 60 W, engraving speed between 0 and 85 mm / min, positioning repeat accuracy: +0.1 mm;

[0081] Step 53: Start the laser engraving equipment and begin the engraving operation; the laser beam engraves, according to the predefined graphic data, the semi-transparent primer, the vacuum plating coating and the finishing varnish, in order to reveal the required symbols;

[0082] Step 54: After engraving, check the quality of the symbols, the color of which must be the transparent color of the plastic substrate; Check if the symbols are complete, clear, if their edges are regular and if there are any residues of primer, plating coating or finishing varnish.

[0083] Step 55: Clean the engraved part to remove debris and impurities generated during engraving.

[0084] According to a preferred embodiment of the invention, in step 6, the specific steps of the ink printing are as follows:

[0085] Step 61: Prepare the ink according to the symbol display requirements, place the part on which the symbols have been laser engraved onto the printing equipment, and then use this equipment to print ink over the symbols.

[0086] Step 62: Adjust the printing equipment settings, which include: printing pressure, speed, and ink flow control, with printing pressure set between 10 and 30 N / cm2; printing speed set between 100 and 500 mm / s; ink flow set between 0.5 and 2 g / m2;

[0087] Step 63: The thickness of the printed ink layer is between 1 and 20 sqm; the ink color is selected for printing according to the required display of the symbols.

[0088] According to a preferred embodiment of the invention, in step 8: an LED light source with a diameter of 2 mm to 6 mm and a power of 0.2 W to 1.6 W is arranged behind the protective varnish on the rear side.

[0089] Compared to the prior art, the invention has the following beneficial effects:

[0090] In the context of the invention: a semi-transparent primer layer is disposed between the vacuum plating layer and the plastic substrate, serving to strengthen the adhesion and cohesion between the vacuum plating coating and the substrate, as well as to resist high temperature and high humidity environments.

[0091] The addition of the protective varnish on the back side improves the reliability of the bond after gluing and eliminates visible glue residue caused by high-temperature and high-humidity environments. This solves the problem inherent in the prior art where, after gluing the part to the surface of the electronic component, glue residue appears that cannot be removed due to prolonged exposure or excessive heat to the vehicle, thus contributing to increased product quality and reliability.

[0092] By applying a UV varnish to the front face of the plastic substrate as a protective front-side varnish, a high-hardness, high-gloss varnish film is formed, significantly improving the wear resistance of the part's surface. This helps to extend the product's service life and reduce appearance and functionality problems caused by wear.

[0093] Thanks to the uniform application of the semi-transparent primer on the back face of the plastic substrate, the adhesion and cohesion between the vacuum plating coating and the substrate are strengthened, ensuring that the coating does not peel or blister easily during prolonged use, and improving the reliability and stability of the product. By using a colored paint with a chrome or alumina layer that is opaque black, the phenomenon of light leakage during the vacuum plating process is effectively prevented.

[0094] Thanks to the natural film formation mode of the protective varnish on the back side, the varnish film is relatively thin but has excellent adhesion; its gloss is uniform but not excessive, which allows LED light to pass through and present clear and bright symbols, thus enhancing the visual effect and the appeal of the product. DESCRIPTION OF THE FIGURES

[0095] [Fig.1] is a logic diagram of the method without backlighting according to the invention.

[0096] [Fig.2] is a logic diagram of the method with backlighting according to the invention. DETAILED IMPLEMENTATION METHODS

[0097] To make the objectives, technical solutions, and advantages of the embodiments of the invention clearer, the technical solutions of the embodiments of the invention will be clearly and fully described below with reference to the accompanying figures. It is understood that the embodiments described represent a specific execution of the invention, without covering all possible embodiments.

[0098] Therefore, the detailed description below of embodiments of the invention is not intended to limit the scope of the invention, but only to represent certain embodiments of the invention. All other embodiments obtained by a person skilled in the art based on the embodiments of the invention without creative effort fall within the scope of the invention.

[0099] It should be noted that, in non-conflicting cases, embodiments of the invention, as well as their technical features and solutions, can be combined. It should also be noted that numerical references and similar letters designate analogous elements in the figures below. Therefore, once an element is defined in a figure, it is no longer necessary to redefine or explain it further in subsequent figures.

[0100] Embodiment 1: [Fig. 1] represents a vacuum plating treatment process for bonding plastics without backlighting, which comprises the following steps:

[0101] SI. Preparation of materials:

[0102] - select a transparent plastic substrate and a protective varnish on the front side;

[0103] - prepare a semi-transparent primer;

[0104] - select the coating material for vacuum plating;

[0105] - prepare a finishing varnish and a protective varnish for the back side.

[0106] S2. Application of the protective varnish to the front side:

[0107] - apply by spraying or brushing onto the front face of the plastic substrate;

[0108] - use ultraviolet equipment to then harden the protective varnish on the side before application, in order to form a high-hardness, high-gloss varnish film.

[0109] S3. Application of the semi-transparent primer:

[0110] - apply the semi-transparent primer evenly to the back face of the substrate plastic;

[0111] - proceed with high-temperature drying of the rear side of the coated plastic substrate semi-transparent primer.

[0112] S4. Vacuum plating:

[0113] - place the substrate coated with the semi-transparent primer in equipment vacuum plating for vacuum plating treatment;

[0114] S5. Application of the finishing varnish:

[0115] - after vacuum plating, apply the finishing varnish by spraying or coating on the external surface;

[0116] S6. Application of the protective varnish to the rear side:

[0117] - apply the protective varnish to the back side of the external surfaces of the varnish finishing and printing ink.

[0118] SI. Material preparation: said plastic substrate is a transparent plastic substrate, said transparent plastic substrate comprises a PMMA (acrylic) substrate and a PC (polycarbonate) substrate.

[0119] S2. Application of the protective varnish on the front side: said protective varnish on the front side is a UV varnish with a thickness of 10 to 50 sqm; it is a varnish crosslinked by ultraviolet radiation, the raw material of which is an epoxy resin; it has high hardness and gloss, and is intended to protect the substrate as well as to improve the wear resistance of the surface of the parts.

[0120] S3. Application of the semi-transparent primer: said semi-transparent base coat It has a thickness of 10 to 60 sqm, it is intended to strengthen the adhesion and cohesion between the coating and the vacuum plating substrate, in order to withstand high temperature and high humidity environments.

[0121] S4. Vacuum plating, said vacuum plating coating has a thickness from 0.1 to 15 sqm, said coating is a colored paint with a chrome layer or a colored paint with an aluminized layer, said vacuum plating coating has a thickness of 20 to 50 sqm, said coating is an opaque black paint to prevent light leakage.

[0122] S6. Application of the protective varnish to the rear side: said protective varnish to the rear This is a UV or PU varnish, 10 to 50 sq m thick, that forms a film naturally. The varnish film, relatively thin and soft, exhibits exceptional adhesion. Its gloss is uniform, without excessive brightness, providing an excellent display effect. Furthermore, it improves the reliability of the bond after application and eliminates visible adhesive residue caused by high-temperature and high-humidity environments.

[0123] Embodiment 2: [Fig. 1] represents a vacuum plating treatment process for bonding plastics with backlighting, which comprises the following steps:

[0124] Step 1: Apply a protective varnish to the front side of the plastic substrate by spraying or brushing; then harden said varnish by exposure to ultraviolet light to form a hard, high-gloss film.

[0125] Step 2: Apply the semi-transparent primer evenly to the back face of the plastic substrate; then, proceed to high-temperature drying of the back side of the plastic substrate coated with the semi-transparent primer.

[0126] Step 3: Place the substrate coated with the semi-transparent primer into a vacuum plating equipment for vacuum plating treatment, the thickness of the plating coating being between 0.1 pm and 15 pm;

[0127] Step 4: After vacuum plating, apply the finishing varnish by spraying or brushing onto the external surface;

[0128] Step 5: Laser engraving of symbols: Laser engrave the required display symbols by removing the semi-transparent primer, vacuum plating coating and finishing varnish, the color of the symbols being that of the plastic substrate.

[0129] Step 6: Printing the ink: Print a layer of translucent ink over the symbols, the color of the ink being determined according to the required display of the symbols;

[0130] Step 7: Apply a protective varnish to the front side of the external surfaces of the finishing varnish and printed ink;

[0131] Step 8: An LED light source is arranged behind the protective varnish on the back side; the LED light passes through the protective varnish on the back side and the printed ink, then through the plastic substrate and the protective varnish on the front side to be visible.

[0132] In step 5, Laser engraving of symbols, the specific steps are as follows:

[0133] Step 51: Prepare the laser engraving equipment; secure the already treated part with semi-transparent primer, vacuum plating coating and finishing varnish on the laser engraving equipment worktable, ensuring that the part is stable and positioned accurately; import graphic data corresponding to the symbols to be displayed into the laser engraving equipment control system according to the required design.

[0134] Step 52: Set the laser engraving parameters, which include: laser power configured between 50 and 60 W, engraving speed between 0 and 85 mm / min, positioning repeat accuracy: +0.1 mm;

[0135] Step 53: Start the laser engraving equipment and begin the engraving operation; the laser beam engraves, according to the predefined graphic data, the semi-transparent primer, the vacuum plating coating and the finishing varnish, in order to reveal the required symbols;

[0136] Step 54: After engraving, check the quality of the symbols, the color of which must be the transparent color of the plastic substrate; Check if the symbols are complete, clear, if their edges are regular and if there are any residues of primer, plating coating or finishing varnish.

[0137] Step 55: Clean the engraved part to remove debris and impurities generated during engraving.

[0138] Step 6, the specific steps for printing the ink are as follows:

[0139] Step 61: Prepare the ink according to the symbol display requirements, place the part on which the symbols have been laser engraved onto the printing equipment, and then use this equipment to print ink over the symbols.

[0140] Step 62: Adjust the printing equipment settings, which include: printing pressure, speed, and ink flow control, with printing pressure set between 10 and 30 N / cm2, printing speed set between 100 and 500 mm / s, and ink flow set between 0.5 and 2 g / m2;

[0141] Step 63: The thickness of the printed ink layer is between 1 and 20 sqm; the ink color is selected for printing according to the required display of the symbols.

[0142] A protective varnish on the front side is a UV varnish with a thickness of 10 to 50 sqm; it is a varnish crosslinked by ultraviolet radiation, the raw material of which is an epoxy resin; it has high hardness and gloss, and is intended to protect the substrate as well as to improve the wear resistance of the surface of the parts.

[0143] Plastic substrate: a transparent plastic substrate is used; in this embodiment, PMMA (acrylic) is selected, but it is also possible to choose a transparent PC (polycarbonate) substrate.

[0144] Semi-transparent primer: it is of a thickness of 10 sqm to 60 sqm, used to strengthen the adhesion and cohesion between the vacuum plating coating and the substrate, in order to withstand environments with high temperature and humidity.

[0145] Vacuum plating: said vacuum plating coating has a thickness of 0.1 to 15 sqm, said coating is a coloured paint with a chrome layer or a coloured paint with an aluminized layer, said vacuum plating coating has a thickness of 20 to 50 sqm, said coating is an opaque black paint to prevent light leakage.

[0146] Protective varnish on the back side: This can be a UV or PU varnish, with a thickness of 10 to 50 sq m. In this embodiment, the protective varnish on the back side is a PU varnish, a generic term for polyester paints. It forms a film naturally, without any special process. Its characteristics are as follows: its varnish film is relatively thin and not very hard, and exhibits exceptional adhesion. Its gloss is uniform, without excessive brightness, which provides an excellent presentation. Furthermore, it improves the reliability of the bond after application and eliminates visible adhesive residue caused by high-temperature and high-humidity environments.

[0147] Laser engraving of symbols: laser engraving to remove the semi-transparent primer, vacuum plating coating and topcoat, and engraving the symbols display required, the color of the symbols being that of the plastic substrate, i.e. a transparent color.

[0148] Ink printing: A translucent ink layer with a thickness of 1 to 20 µm is printed over the symbols, the ink color being printed according to the symbol display requirements. In this embodiment, white ink is used. The LED light can pass through the protective varnish on the back side and the printed ink, then through the plastic substrate and the protective varnish on the front side to become visible.

[0149] Strengthening adhesion and cohesion: thanks to the placement of a semi-transparent primer layer between the vacuum plating coating and the plastic substrate, the adhesion and cohesion between the coating and the substrate are significantly strengthened, enabling it to withstand high temperature and high humidity environments and preventing peeling or damage to the coating.

[0150] Improved adhesion reliability: The addition of a protective varnish to the back side of the part, such as the PU varnish chosen in this invention, which exhibits excellent adhesion, increases the reliability of the adhesion after bonding. At the same time, this protective varnish eliminates adhesive residue that may appear due to high temperature and high humidity environments, thus ensuring the integrity and aesthetic appearance of the part.

[0151] Substrate protection and improved wear resistance: The use of a protective varnish on the front side, a UV-based epoxy resin varnish with a thickness of 10 to 50 µm, provides a high-hardness, high-gloss varnish film. This protective varnish effectively protects the substrate, improves the wear resistance of the part's surface, and extends the part's service life.

[0152] Adaptation to various substrates: the plastic substrate can be a PMMA (acrylic) plastic substrate, or a transparent PC (polycarbonate) substrate, thus offering more choices for design and application.

[0153] Thanks to the use of a semi-transparent primer, with a thickness of 10 to 60 µm, not only is adhesion enhanced, but during laser engraving of the symbols, the engraved symbols exhibit the transparent color of the plastic substrate. A layer of translucent ink is then printed over the symbols, and the ink color can be selected according to the display requirements of the symbols, such as the white ink used in this embodiment. This design allows the LED light to pass through the protective varnish on the back side and the printed ink, and then through the plastic substrate and the protective varnish on the front side to become visible, thus achieving an excellent display effect.

[0154] The invention solves the problem posed by the appearance of ineradicable traces of glue after the part has been glued to the surface of the electronic component due to a prolonged use or exposure to intense heat from the vehicle, thus improving the quality and reliability of the product.

[0155] In embodiment 3, [Fig. 1] represents a vacuum plating treatment process for bonding plastics, which uses the following materials: a transparent PMMA (acrylic) plastic substrate is chosen; a semi-transparent primer with a thickness of 30 µm is prepared; a vacuum plating material is used to form a coating layer; in this embodiment, a chrome layer with a thickness of 5 µm is chosen; an opaque black colored paint with a thickness of 30 µm is chosen; a PU varnish with a thickness of 30 µm is chosen for the protective varnish on the back side; a white ink with a thickness of 10 µm is chosen for printing the symbols; a UV varnish with a thickness of 30 µm is chosen for the protective varnish on the front side.

[0156] Application of the semi-transparent primer: Clean the PMMA plastic substrate to remove dust and impurities from its surface. Apply the semi-transparent primer evenly to the plastic substrate using application equipment, ensuring a thickness of 30 sq m. Place the primer-coated substrate in a drying oven and dry it at a suitable temperature to enhance adhesion between the primer and the substrate.

[0157] Vacuum plating: Place the primer-coated substrate in a vacuum plating unit. Under vacuum conditions, heat the chrome material until it evaporates to form gaseous atoms or molecules, which are deposited on the substrate surface to form a chrome layer 5 µm thick.

[0158] Application of the colored paint: After the vacuum plating is complete, remove the substrate and cool it to room temperature. Apply the black paint evenly over the chrome layer using application equipment, ensuring a colored paint thickness of 30 sq m. Place the colored-painted substrate back into an oven for drying.

[0159] Application of the protective varnish to the back side: After the colored paint has dried, remove the substrate and apply the PU varnish to its back side, with a thickness of 30 sq m. Allow the PU varnish to form a film naturally, without the need for special processes.

[0160] Application of the protective varnish to the front side: After printing the ink, apply the UV varnish to the front face of the substrate, with a thickness of 30 sq m. Use ultraviolet irradiation equipment to cure the UV varnish, so that it forms a high-hardness and high-gloss film, thus protecting the substrate and improving the wear resistance of the surface of the part.

[0161] Thanks to the specific embodiments above, it is possible to implement a vacuum plating treatment process for bonding plastics. This process effectively prevents the appearance of glue residue during practical use, while offering the product more diverse and enriched colours, and being more ecological and non-polluting.

[0162] In embodiment 4, [Fig.2] represents a vacuum plating treatment process for bonding plastics, which uses the following materials: a transparent PC (polycarbonate) plastic substrate is selected; a semi-transparent primer with a thickness of 40 µm is selected; an aluminized layer with a thickness of 8 µm is selected as the vacuum plating material; a black colored paint with a thickness of 40 µm is selected; a UV backside protective varnish with a thickness of 40 µm is selected; a blue printing ink with a thickness of 15 µm is selected; a UV frontside protective varnish with a thickness of 40 µm is selected.

[0163] Application of the semi-transparent primer: Clean the PC plastic substrate to obtain a clean surface, and apply the semi-transparent primer evenly to the plastic substrate using application equipment, ensuring a primer thickness of 40 µm. Place the primer-coated substrate in a drying oven to dry at the appropriate temperature.

[0164] Vacuum plating: Place the substrate in a vacuum plating unit. Under vacuum conditions, heat the aluminum material until it vaporizes, so that it is deposited as atoms or gaseous molecules on the surface of the substrate to form an aluminized layer with a thickness of 8 pm.

[0165] Application of the colored paint: After the vacuum plating is complete, remove the substrate and allow it to cool. Use application equipment to evenly deposit the black paint onto the aluminized layer, ensuring a thickness of 40 µm. Place the colored-paint coated substrate in an oven to dry.

[0166] Application of protective varnish on the back side: After the colored paint has dried, remove the substrate and apply the UV varnish to its back side, with a thickness of 40 µm.

[0167] Use ultraviolet rays to harden the UV varnish, so as to form a protective layer.

[0168] Laser engraving of symbols: Use laser engraving technology to remove the semi-transparent primer, vacuum plating coating, and colored paint according to the required design, in order to form the required display symbols. The color of the symbols is that of the plastic substrate.

[0169] Ink printing: Above the engraved symbols, use printing equipment to print a layer of blue ink with a thickness of 15 µm.

[0170] Application of the protective varnish to the front side: After printing the ink, apply the UV varnish to the front side of the substrate, with a thickness of 40 µm. The UV varnish is hardened by exposure to ultraviolet light to form a solid film, which serves to protect the substrate and improve surface performance.

[0171] Application of the front-side protective varnish: On the front face of the plastic substrate, apply the front-side protective varnish (UV varnish) by spraying or brushing, with a thickness between 10 and 50 sqm, use ultraviolet equipment to cure the applied front-side protective varnish, so that it forms a high-hardness and high-gloss film, which protects the substrate and improves the wear resistance of the surface of the part.

[0172] Application of the semi-transparent primer: On the back face of the plastic substrate, apply the semi-transparent primer evenly, with a thickness between 10 and 60 sqm; ensure complete drying of the primer to strengthen the adhesion and cohesion between the vacuum plating coating and the substrate, in order to improve the stability of the product in high temperature and high humidity environments.

[0173] Vacuum plating: Place the plastic substrate coated with the semi-transparent primer in vacuum plating equipment for vacuum plating treatment. Choose a colored chrome-plated or aluminized-plated paint as the coating material, and control the plating thickness between 0.1 and 15 sqm, and the coating thickness between 20 and 50 sqm;

[0174] To ensure a uniform and dense coating, and consists of an opaque black paint, in order to prevent light leakage.

[0175] Application of the finishing varnish: After vacuum plating, apply the finishing varnish by spraying or brushing onto the external surface to improve the appearance quality and corrosion resistance of the product; ensure complete drying of the finishing varnish to form a uniform and smooth varnish film.

[0176] Printing ink adjustment: On the outer surface of the finishing varnish, adjust the ink by printing; ensure that the printed ink patterns are clear, precise and the colors are vivid.

[0177] Laser engraving of symbols: Use laser engraving equipment to engrave the required symbols onto the printed ink; control the laser engraving parameters to ensure the clarity and accuracy of the symbols.

[0178] Application of the protective varnish on the back side: On the external surfaces of the finishing varnish and the printed ink, apply the protective varnish on the back side (UV or PU varnish), with a thickness between 10 and 50 sqm.

[0179] Experimental example

[0180] Objective of the experiment:

[0181] 1. Check if the new process eliminates traces of glue.

[0182] 2. Test whether the adhesion and cohesion of the coating are enhanced within the framework of the new process.

[0183] 3. Verify whether the new process can improve the wear resistance of the surface parts.

[0184] 4. Evaluate whether the visual effect of the new process meets the specifications.

[0185] Experimental materials:

[0186] Transparent PMMA (acrylic) plastic substrate; semi-transparent primer; vacuum plating coating (chrome layer); protective varnish on the front side (UV varnish); protective varnish on the back side (PU varnish); translucent ink.

[0187] Experimental steps:

[0188] Step 1. Prepare a PMMA substrate and clean the surface.

[0189] Step 2. Apply a semi-transparent primer with a thickness of 10 to 60 sq m on the PMMA substrate, then perform vacuum plating after hardening to form a chrome layer with a thickness of 0.1 to 15 sqm.

[0190] Step 3. Apply an opaque black paint with a thickness of 20 to 50 sqm over the chrome layer to prevent light leakage.

[0191] Step 4. Apply a PU varnish with a thickness of 10 to 50 sqm as a protective varnish on the back side.

[0192] Step 5. Use a laser engraving machine to engrave the required symbols on the surface of the part and reveal the color of the PMMA substrate.

[0193] Step 6. Print a layer of translucent white ink with a thickness of 1 to 20 sqm over the symbols.

[0194] Step 7. Once the above steps have been completed, subject the part to aging tests under conditions of high temperature and high humidity, as well as abrasion tests and an evaluation of the visual effect.

[0195] Experimental data: Test Item Parameter Traditional Process Result New Process Result Improvement Rate (%) Glue Traces Glue Traces after High Temperature Exposure Visible Traces No Trace 100 Coating Adhesion Adhesion Test (N / mm2) 5 6.5 30 Abrasion Resistance Number of Abrasion Cycles 1000 1200 20 Visual Effect Clarity and Vibrancy of Colors Clear, Vibrant Colors -

[0196] Experimental analyses:

[0197] 1. Traces of glue:

[0198] In the traditional process, obvious traces of glue appear after exposure to high temperature, which seriously affects the aesthetic quality of the product.

[0199] The new process effectively eliminates traces of glue caused by high temperature and high humidity environments by adding a PU protective varnish to the back of the parts as a protective layer, in order to preserve the integrity and aesthetics of the part.

[0200] 2. Coating adhesion:

[0201] The adhesion of the coating of the traditional process is only 5N / mm2, which is a low figure, and it is likely to detach or be damaged in a high temperature and high humidity environment.

[0202] By interposing a semi-transparent primer layer between the vacuum plating coating and the plastic substrate, the new process significantly strengthens the adhesion of the coating to 6.5 N / mm2, an increase of 30%, and improves resistance to high temperature and high humidity environments.

[0203] 3. Wear resistance:

[0204] The traditional process exhibits low wear resistance, with only 1,000 abrasion cycles supported, which considerably limits the product's lifespan.

[0205] By using a UV varnish as a protective varnish for the front face, the new process improves the wear resistance of the surface of the parts, and increases the number of abrasion cycles to 1200, which is equivalent to an increase in service life of at least 20%.

[0206] 4. Display effect:

[0207] In terms of display effect, the traditional method has drawbacks: the symbols are not sufficiently clear and the colours lack vibrancy.

[0208] The new process, thanks to its design incorporating a semi-transparent primer and translucent ink, allows LED light to pass through the protective varnish on the back side and the printed ink, then through the plastic substrate and the protective varnish on the front side to become visible. This results in optimal display with perfectly legible symbols and vibrant colors.

[0209] Conclusion: The vacuum plating process for bonding plastics proposed by the invention successfully solves several key problems of the existing process: glue residue, insufficient coating adhesion, low wear resistance, and poor display effect. Experimental tests confirm that the new process significantly improves product quality and reliability.

[0210] Specific advantages:

[0211] - Total elimination of traces of glue after exposure to high temperature, which preserves the integrity and aesthetics of the pieces.

[0212] - Coating adhesion increased by 30%, which strengthens resistance to environments with high temperature and high humidity.

[0213] - Improved wear resistance, which extends the service life by at least 20%.

[0214] - Optimal display with legible symbols and bright colors, which satisfies the high requirements for automotive electronic components for decorative elements.

[0215] In summary, the vacuum plating process and method for bonding plastics, according to the invention, successfully solve the problems of existing processes: glue residue, insufficient adhesion, low wear resistance, and poor display effect. It significantly improves product quality and reliability.

[0216] The above embodiments serve only to illustrate the invention without limiting its technical scope. Although the description explains the invention in detail by reference to the above embodiments, the invention is not limited to these specific embodiments. Any equivalent modification or substitution to the invention, as well as any technical solution and its improvement, shall be included within the scope of the present invention.

Claims

Demands

1. A method for manufacturing a substrate having a front face and a back face on which a coating is applied by vacuum plating, characterized in that it comprises the following steps: S1. Preparation of materials: - select a transparent plastic substrate and a protective varnish for application to the front face of the substrate; - prepare a semi-transparent primer; - select a coating material for vacuum plating; - prepare a topcoat and a protective varnish for application to the back face of the substrate; S2. Application of the protective varnish to the front face of the substrate: - apply the protective varnish by spraying or brushing onto the front face of the substrate; - use ultraviolet equipment on the front side to subsequently harden the varnish applied to the front face, in order to form a high-hardness, high-gloss varnish film; S3.Application of the semi-transparent primer: - apply the semi-transparent primer evenly to the back side of the substrate; - proceed with high-temperature drying of the back side of the substrate coated with the semi-transparent primer; S4. Vacuum plating: - place the substrate coated with the semi-transparent primer in vacuum plating equipment for vacuum plating over the semi-transparent primer; S5. Application of the topcoat: - after vacuum plating, apply the topcoat by spraying or brushing onto the outer surface of the plating; S6. Application of the protective backcoat: - apply the protective backcoat over the outer surface of the topcoat.

2. A method according to claim 1, characterized in that at step SI, said transparent plastic substrate is an acrylic plastic substrate, such as PMMA, or a polycarbonate substrate, PC.

3. A method according to any one of claims 1 and 2, characterized in that at step S2, said front-side protective varnish is a UV varnish with a thickness of 10 to 50 µm or said front-side protective varnish is a varnish cross-linked by ultraviolet radiation, the raw material of which is an epoxy resin.

4. A method according to any one of claims 1 to 3, characterized in that at step S3, said semi-transparent primer has a thickness of 10 to 60 µm.

5. A method according to any one of claims 1 to 4, characterized in that at step S4, said vacuum plating coating has a thickness of 0.1 to 15 µm, said coating then being a coloured paint with a chrome layer or a coloured paint with an aluminized layer or said vacuum plating coating has a thickness of 20 to 50 µm, said coating then being an opaque black paint.

6. A method according to any one of claims 1 to 5, characterized in that at step S6, said rear-side protective varnish is a UV varnish or a PU varnish with a thickness of 10 to 50 µm, said varnish being film-forming.

7. A method according to any one of claims 1 to 6, characterized in that after step S5, the following additional steps are carried out: S5i.Backside laser engraving of symbols: - Laser engrave required display symbols by removing the semi-transparent primer, vacuum plating coating and topcoat, the color of the symbols being that of the substrate; S52:: Ink printing: Print a layer of translucent ink on the symbols, the ink color being determined according to the required display of the symbols; the backside protective varnish of step S6 is then applied to the external surfaces of the topcoat and the printed ink; and by the fact that after step S6, an LED light source is arranged behind the backside protective varnish; the LED light passes through the backside protective varnish and the printed ink, then through the substrate and the frontside protective varnish to be visible.

8. A method according to claim 7, characterized in that, in step S5i, the specific steps of laser engraving the symbols are as follows: a1: Prepare the laser engraving equipment; fix the substrate already treated with the semi-transparent primer, vacuum plating, and finishing varnish onto the worktable of the laser engraving equipment; b1: Set the laser engraving parameters, which include: the laser power configured between 50 and 60 W, the engraving speed between 0 and 85 mm / min, and the positioning repeatability: ±0.1 mm; c1: Start the laser engraving equipment and begin the engraving operation; the laser beam engraves, according to the predefined graphic data, the semi-transparent primer, vacuum plating, and finishing varnish, in order to reveal the required symbols;dl: After engraving, check the quality of the symbols, whose color must be the transparent color of the substrate; el: Clean the engraved part to remove debris and impurities generated during engraving.

9. A method according to any one of claims 7 and 8, characterized in that, at step S52, the specific steps of said ink printing are as follows: Step a2: Prepare the ink according to the symbol display requirements, place the part on which the symbols have been laser-engraved onto the printing equipment, and then use this equipment to print ink onto the symbols; Step b2: Adjust the parameters of the printing equipment, which include: printing pressure, speed, and ink flow control, the printing pressure being set between 10 and 30 N / cm2, the printing speed set between 100 and 500 mm / s, the ink flow set between 0.5 and 2 g / m2; Step c2: The thickness of the printed ink layer is between 1 and 20 sqm; The ink color is selected for printing based on the required display of symbols.

10. A method according to any one of claims 7 to 9, characterized in that after step S6, an LED light source with a diameter of 2 at 6 mm and with a power of 0.2 to 1.6 W is located behind the protective varnish on the rear side.

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