Coating for automobile ornament multi-coating chromatography laser etching scheme, preparation method and application

Abstract

The invention discloses a coating for a multi-coating chromatography laser etching scheme of an automobile ornament, a preparation method and application, and relates to the technical field of industrial coatings, the coating comprises the following specific components: a primer, a chromatography layer and a finishing coat; the primer is prepared from epoxy modified acrylate, nano silicon dioxide, a plasticizer, a photoinitiator, a diluent, a dispersing agent and a flatting agent; the color register layer comprises polyurethane resin, nanoscale color paste, a light stabilizer, a diluent, a dispersing agent and a defoaming agent; the finish paint comprises aliphatic polyurethane acrylate, a reactive diluent, a photoinitiator, a light stabilizer and an antioxidant. Epoxy modified acrylate primer, a color register layer for optimizing the laser absorption characteristic and nano-filler enhanced finish paint are adopted. Wherein it is guaranteed that the primer still has good interlayer adhesive force after multiple times of baking, the color register layer achieves precise laser etching through a specific laser absorbent, the finish paint enhances the anti-scraping capacity and the leveling property, and the surface obtained after laser etching is smoother.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial coatings, and specifically provides a coating, a preparation method and an application for a multi-layer color-matching laser engraving solution for automotive trim parts. Background Art

[0002] In the field of automotive trim parts, the multi-layer color-matching laser engraving process is widely used in the production of high-end decorative parts such as center console panels, door panel trims, and steering wheel decorative strips. Among them, the traditional "wet-on-wet" process (such as 3C1B or 3C2B) is prone to interface blurring and unclear patterns during laser engraving due to incomplete curing between layers. Therefore, the "three-spray three-bake" (3C3B) process is generally adopted in the market, that is, the primer, color-matching layer and topcoat are sprayed separately and baked independently to ensure high contrast and clarity of the laser engraved pattern. However, this solution has the following key problems:

[0003] The adhesion between layers decreases, and it is easy to peel off after long-term use;

[0004] Due to the need for multiple high-temperature baking in the 3C3B process, the multi-layer coatings may be over-cured, resulting in a decrease in the adhesion between layers. Especially the bonding force between the primer and the color-matching layer, and between the color-matching layer and the topcoat is insufficient, and coating delamination or peeling may occur after long-term use.

[0005] Surface defects after laser engraving affect the quality of subsequent coatings;

[0006] The traditional color-matching layer is prone to produce uneven interfaces during laser engraving, affecting the leveling effect of the subsequent topcoat. Especially for high-film-thickness UV coatings with poor fluidity, they cannot effectively fill the uneven surface after laser engraving, thus affecting the overall appearance and durability of the trim parts. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the present invention provides a coating, a preparation method and an application for a multi-layer color-matching laser engraving solution for automotive trim parts to solve the problems raised in the above background art.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] An embodiment of the present invention provides a coating for a multi-layer color-matching laser engraving solution for automotive trim parts, which includes the following specific components: primer, color-matching layer, topcoat;

[0010] The primer includes epoxy-modified acrylate, nano-silica, plasticizer, photoinitiator, diluent, dispersant, leveling agent;

[0011] The color-matching layer includes polyurethane resin, nano-level color paste, light stabilizer, diluent, dispersant, defoaming agent;

[0012] The topcoat includes aliphatic polyurethane acrylate, reactive diluent, photoinitiator, light stabilizer, and antioxidant.

[0013] To further optimize this technical solution, in the primer, it includes the following parts by mass:

[0014] Epoxy-modified acrylate is 50 - 60 parts;

[0015] Nano-silica is 5 - 10 parts;

[0016] Plasticizer is 3 - 5 parts;

[0017] Photoinitiator is 2 - 4 parts;

[0018] Diluent is 20 - 30 parts;

[0019] Dispersant is 1 - 2 parts;

[0020] Leveling agent is 1 - 2 parts.

[0021] To further optimize this technical solution, in the overprint layer, it includes the following parts by mass:

[0022] Polyurethane resin is 50 - 60 parts;

[0023] Nanoscale color paste is 5 - 10 parts;

[0024] Light stabilizer is 3 - 5 parts;

[0025] Diluent is 20 - 30 parts;

[0026] Dispersant is 1 - 2 parts;

[0027] Defoaming agent is 1 - 2 parts.

[0028] To further optimize this technical solution, in the topcoat, it includes the following parts by mass:

[0029] Aliphatic polyurethane acrylate is 40 - 50 parts;

[0030] Reactive diluent is 10 - 20 parts;

[0031] Photoinitiator is 3 - 5 parts;

[0032] Light stabilizer is 2 - 3 parts;

[0033] Antioxidant is 0.5 - 1 part.

[0034] A method for preparing a coating for a multi-layer overprint laser engraving scheme of automotive trim parts, which is prepared based on the coating for the multi-layer overprint laser engraving scheme of automotive trim parts described above, and includes the preparation of the primer, overprint layer, and topcoat;

[0035] When preparing the primer:

[0036] Add nano-silica into the diluent and disperse it evenly.

[0037] Add epoxy-modified acrylate and stir.

[0038] Add a plasticizer, a dispersant, a photoinitiator in sequence, and finally add a leveling agent, and stir evenly to obtain a primer.

[0039] When preparing the overprint varnish layer:

[0040] Add nano-level color paste into the diluent and grind it with a sand mill to control the particle size of the pigment particles below 100 nm.

[0041] Add polyurethane resin and stir.

[0042] Add a light stabilizer, a dispersant, and an antifoaming agent in sequence, and stir evenly to obtain the overprint varnish layer.

[0043] When preparing the topcoat:

[0044] Add aliphatic polyurethane acrylate into the reactive diluent and stir.

[0045] Add a photoinitiator, a light stabilizer, and an antioxidant in sequence, and continue to stir for 20 - 30 minutes to obtain the topcoat.

[0046] To further optimize this technical solution, when preparing the epoxy-modified acrylate, it includes:

[0047] Add epoxy resin and acrylic acid into the flask in proportion, stir until completely dissolved, add a catalyst and an inhibitor, continue to stir for 10 minutes, heat in an oil bath to 80 - 90 °C, turn on the condensing reflux device, and maintain this temperature for reaction for 3 - 4 hours.

[0048] Cool down to 60 °C, slowly add triethylamine to neutralize the excessive acid, adjust the pH to 6.5 - 7.5, add a diluent, and filter while it is hot to remove insoluble impurities; remove the solvent by vacuum distillation to obtain the epoxy-modified acrylate.

[0049] To further optimize this technical solution, when preparing the aliphatic polyurethane acrylate, it includes:

[0050] Add a catalyst and an inhibitor to the dehydrated polyol, and stir evenly; then slowly add aliphatic diisocyanate, control the dropping rate to keep the reaction temperature not exceeding 80 °C; after the dropping is completed, react at 70 - 80 °C for 2 - 3 hours.

[0051] Lower the reaction temperature to about 60 °C, slowly dropwise add hydroxy acrylate, control the dropping rate so that the reaction temperature does not exceed 70 °C; after the dropping is completed, continue the reaction at 60 - 70 °C for 2 - 3 hours until the NCO content drops to undetectable, obtaining aliphatic polyurethane acrylate.

[0052] The coating application of a multi - coating color - overprinting laser engraving solution for automotive trim parts, based on the coating of the above - mentioned multi - coating color - overprinting laser engraving solution for automotive trim parts, includes the application of primer, color - overprinting layer, and topcoat;

[0053] When applying the primer:

[0054] Pretreat the substrate;

[0055] Spray the primer on the substrate by spraying, and let it flow and stand still for 5 - 10 minutes;

[0056] Cure it in an oven at 80 - 120 °C for 30 minutes to ensure complete cross - linking of the coating, and then naturally cool to room temperature;

[0057] When applying the color - overprinting layer:

[0058] Select a single - color or gradient color - overprinting scheme according to the design requirements;

[0059] Spray the color - overprinting layer by wiping or spraying, and let it stand still for 10 minutes after spraying;

[0060] Cure it in an oven at 80 - 100 °C for 20 - 30 minutes to ensure the curing of the coating, and then naturally cool to room temperature;

[0061] When applying the topcoat:

[0062] Uniformly apply the topcoat by spraying or roller coating;

[0063] After spraying, put it into a UV curing device, and make the topcoat cure quickly by ultraviolet irradiation to improve durability and scratch resistance.

[0064] To further optimize this technical solution, the coating application also includes the application of laser engraving, including surface treatment, equipment debugging, positioning and clamping, engraving operation, and laser engraving effect inspection.

[0065] To further optimize this technical solution, during the engraving operation, align with the pattern position, use a CCD vision positioning system to ensure precise engraving, adopt a line - by - line scanning method to remove the color - overprinting layer, expose the primer or substrate, and adjust the focal length and scanning times to ensure that the depth of laser engraving is 3 - 10 μm.

[0066] Compared with the prior art, the present invention provides a coating, preparation method and application of a multi - coating color - overprinting laser engraving solution for automotive trim parts, having the following beneficial effects:

[0067] The coating, preparation method and application of the multi - coating color - matching laser engraving solution for automotive trim parts adopt an epoxy - modified acrylate primer, a color - matching layer with optimized laser absorption characteristics, and a topcoat enhanced with nano - fillers. Among them, the primer ensures good inter - layer adhesion after multiple bakings. The color - matching layer realizes precise laser engraving through specific laser absorbers, and the topcoat enhances the scratch - resistance and leveling property, making the surface after laser engraving smoother. It not only improves the clarity of the laser - engraved pattern and the inter - layer bonding force, but also effectively expands the scope of application in the fields of automotive trim parts, home coatings and industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following - described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0069] Figure 1 It is a schematic diagram of the composition of the coating for a multi - coating color - matching laser engraving solution for automotive trim parts proposed by the present invention;

[0070] Figure 2 It is a schematic flow chart of the preparation method of the coating for a multi - coating color - matching laser engraving solution for automotive trim parts proposed by the present invention;

[0071] Figure 3 It is a schematic flow chart of the application of the coating for a multi - coating color - matching laser engraving solution for automotive trim parts proposed by the present invention;

[0072] Figure 4 It is a schematic diagram of one of the products of the coating for a multi - coating color - matching laser engraving solution for automotive trim parts proposed by the present invention;

[0073] Figure 5 It is a schematic diagram of the second product of the coating for a multi - coating color - matching laser engraving solution for automotive trim parts proposed by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0074] To make the above - mentioned objects, features and advantages of the present invention more obvious and understandable, the following will give a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings of the specification.

[0075] In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can also be implemented in other ways different from this description. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0076] Secondly, the "one embodiment" or "embodiment" mentioned herein refers to specific features, structures or characteristics that may be included in at least one implementation of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or selectively exclusive embodiments from other embodiments.

[0077] Embodiment 1:

[0078] Referring to Figure 1 , which is the first embodiment of the present invention. This embodiment provides a coating for a multi - layer color - matching laser engraving solution for automotive trim parts, including the following specific components: primer, color - matching layer, and topcoat;

[0079] The primer includes epoxy - modified acrylate, nano - silica, plasticizer, photo - initiator, diluent, dispersant, and leveling agent.

[0080] The color - matching layer includes polyurethane resin, nano - level color paste, light stabilizer, diluent, dispersant, and defoaming agent.

[0081] The topcoat includes aliphatic polyurethane acrylate, reactive diluent, photo - initiator, light stabilizer, and antioxidant.

[0082] In the primer, by mass fraction, it includes:

[0083] Epoxy - modified acrylate is 50 - 60 parts;

[0084] Nano - silica is 5 - 10 parts;

[0085] The plasticizer uses dibutyl phthalate, which is 3 - 5 parts;

[0086] The photo - initiator uses TPO - L, which is 2 - 4 parts;

[0087] The diluent uses toluene or ethyl acetate, which is 20 - 30 parts;

[0088] The dispersant uses BYK - 110, which is 1 - 2 parts;

[0089] The leveling agent uses EFKA - 3030, which is 1 - 2 parts.

[0090] In the color - matching layer, by mass fraction, it includes:

[0091] Polyurethane resin is 50 - 60 parts;

[0092] The nano - level color paste uses organic / inorganic pigments, which is 5 - 10 parts;

[0093] The light stabilizer uses TINUVIN 292, which is 3 - 5 parts;

[0094] The diluent uses PMA (propylene glycol monomethyl ether acetate), with a quantity of 20 - 30 parts;

[0095] The dispersant uses BYK - 180, with a quantity of 1 - 2 parts;

[0096] The defoamer uses TEGO 410, with a quantity of 1 - 2 parts.

[0097] In the topcoat, it includes the following parts by mass:

[0098] The aliphatic polyurethane acrylate is 40 - 50 parts;

[0099] The reactive diluent uses TPGDA / ETPTA, with a quantity of 10 - 20 parts;

[0100] The photoinitiator uses TPO / 819, with a quantity of 3 - 5 parts;

[0101] The light stabilizer uses TINUVIN 123, with a quantity of 2 - 3 parts;

[0102] The antioxidant uses BHT, with a quantity of 0.5 - 1 part.

[0103] Example Two:

[0104] Refer to Figure 2 , which is the second example of the present invention. This example provides a method for preparing a coating for a multi - layer color - coated laser engraving scheme for automotive trim parts. Based on the coating for the multi - layer color - coated laser engraving scheme for automotive trim parts described in Example One, it includes the preparation of the primer, color - coated layer, and topcoat;

[0105] When preparing the primer:

[0106] Add nano - silica into the diluent and disperse it evenly;

[0107] Add epoxy - modified acrylate and stir;

[0108] Add the plasticizer, dispersant, photoinitiator in sequence, and finally add the leveling agent, stir evenly, and disperse at high speed until the viscosity ≤ 150 cP to obtain the primer;

[0109] When preparing the color - coated layer:

[0110] Add nano - scale color paste into the diluent and grind it using a sand mill to control the pigment particle size below 100 nm;

[0111] Add polyurethane resin and stir;

[0112] Add the light stabilizer, dispersant, defoamer in sequence, stir evenly to obtain the color - coated layer;

[0113] When preparing the topcoat:

[0114] Add aliphatic polyurethane acrylate to the reactive diluent and stir.

[0115] Add a photoinitiator, a light stabilizer, and an antioxidant in sequence and continue stirring for 20 - 30 minutes to obtain the topcoat.

[0116] When preparing the epoxy - modified acrylate, it includes:

[0117] Add epoxy resin and acrylic acid to a flask in proportion, stir until completely dissolved, add a catalyst (tetrabutylammonium bromide) and an inhibitor (hydroquinone), continue stirring for 10 minutes, heat in an oil bath to 80 - 90 °C, turn on the condenser reflux device, and maintain this temperature for reaction for 3 - 4 hours.

[0118] Cool down to 60 °C, slowly add triethylamine to neutralize the excess acid, adjust the pH to 6.5 - 7.5, add a diluent (such as toluene), and filter while it is hot to remove insoluble impurities; remove the solvent by vacuum distillation to obtain the epoxy - modified acrylate.

[0119] When preparing the aliphatic polyurethane acrylate, it includes:

[0120] Add a catalyst (dibutyltin dilaurate) and an inhibitor (p - methoxyphenol) to the dehydrated polyol, stir evenly; then slowly add aliphatic diisocyanate, control the dropping rate so that the reaction temperature does not exceed 80 °C; after dropping, react at 70 - 80 °C for 2 - 3 hours.

[0121] Lower the reaction temperature to about 60 °C, slowly add hydroxy - acrylate, control the dropping rate so that the reaction temperature does not exceed 70 °C; after dropping, continue to react at 60 - 70 °C for 2 - 3 hours until the NCO content cannot be detected to obtain the aliphatic polyurethane acrylate.

[0122] Example 3:

[0123] Refer to Figures 3 - 5 , which is the third embodiment of the present invention. This embodiment provides a coating application for a multi - coating color - overprinting laser engraving scheme for automotive trim parts. Based on the coating for a multi - coating color - overprinting laser engraving scheme for automotive trim parts described in Example 1, it includes the application of the primer, the color - overprinting layer, and the topcoat.

[0124] When applying the primer:

[0125] Pretreat the substrate. For example, for a metal substrate, use sandblasting and phosphating treatments to increase surface roughness and activity.

[0126] Spray the primer on the substrate by spraying, and let it flow and stand still for 5 - 10 minutes.

[0127] Cure at 80 - 120 °C in an oven for 30 minutes to ensure complete cross-linking of the coating, and then cool naturally to room temperature;

[0128] When applying the overprint layer:

[0129] Select a single-color or gradient overprinting scheme according to the design requirements;

[0130] Spray the overprint layer by rubbing or spraying, and let it stand for 10 minutes after spraying;

[0131] Cure at 80 - 100 °C in an oven for 20 - 30 minutes to ensure coating curing, and then cool naturally to room temperature;

[0132] When applying the topcoat:

[0133] Apply the topcoat evenly by spraying or rolling;

[0134] After spraying, put it into a UV curing device, and cure the topcoat quickly by ultraviolet irradiation to improve durability and scratch resistance.

[0135] The coating application also includes the application of laser engraving, which is carried out after the application of the overprint layer and before the application of the topcoat; specifically including:

[0136] Surface treatment: Use solvents such as alcohol and acetone or equipment such as high-pressure water guns to remove oil stains, dust, impurities, etc. on the material surface to ensure good coating adhesion and laser engraving effect.

[0137] Equipment debugging: Select a suitable laser device according to the material characteristics and laser engraving requirements, and debug parameters such as laser power, speed, and frequency.

[0138] Positioning and clamping: Place the workpiece coated with the coating accurately on the working table of the laser engraving machine and fix it with a fixture to ensure no movement during the engraving process.

[0139] Engraving operation: Start the laser engraving machine and engrave according to the preset pattern and parameters. The laser beam acts on the coating surface to cause physical or chemical changes in the coating to form a pattern.

[0140] Inspection of laser engraving effect: Check the clarity, accuracy, integrity of the laser engraving pattern, as well as the adhesion between the coating and the substrate, etc. Rework or scrap unqualified products.

[0141] Furthermore, during the engraving operation, align with the pattern position, use a CCD vision positioning system to ensure precise engraving, adopt a line-by-line scanning method to remove the overprint layer, expose the primer or substrate, and adjust the focal length and scanning times to ensure that the laser engraving depth is 3 - 10 μm. Thus, a coating product with a laser pattern as shown in Figure 4 and Figure 5 can be obtained.

[0142] At the same time, performance tests are carried out on the coating products using the test items shown in Table 1.

[0143] Table 1 Performance Test

[0144]

[0145]

[0146]

[0147] Example 4:

[0148] In order to adapt to different application environments and requirements, the following several changeable design schemes are proposed in this example:

[0149] Regarding the primer:

[0150] Adjust the type and dosage of photoinitiators, select photoinitiators that match the laser wavelength and energy, such as for ultraviolet laser engraving, select photoinitiators with absorption peaks close to the laser wavelength, and determine the optimal dosage through experiments to improve the speed and accuracy of engraving.

[0151] Add functional fillers, such as carbon black, carbon nanotubes, etc., to increase the absorption of laser energy by the primer and make the engraved pattern clearer and the contrast higher.

[0152] Add plasticizers to the primer, use resins with better flexibility, such as polyurethane acrylate elastomers, and use them in combination with other resins to adjust the balance between the flexibility and hardness of the primer to adapt to different usage scenarios.

[0153] Optimize the rheological properties of the primer. By adding rheological aids, such as fumed silica, bentonite, etc., adjust the viscosity and thixotropy of the primer so that it is not prone to sagging during spraying or brushing, and at the same time has good leveling properties.

[0154] Regarding the overprint layer:

[0155] Select pigments with high purity, uniform particle size and good dispersibility. For example, use organic pigments to replace part of the inorganic pigments to improve the color brightness and saturation.

[0156] After spraying the primer, bake it. After baking at 60 °C for 45 minutes, then spray the overprint layer to ensure uniform film thickness and avoid bleeding with the primer.

[0157] Regarding the topcoat:

[0158] Select high-performance resins, such as aliphatic polyurethane acrylate, which has excellent weather resistance, wear resistance and flexibility, can effectively protect the engraved pattern, and at the same time make the varnish have good mechanical properties.

[0159] Reasonably mix active diluents, such as the compounding of tripropylene glycol diacrylate (TPGDA) and ethoxylated trimethylolpropane triacrylate (ETPTA), to adjust the viscosity of the varnish, ensure good leveling property and construction performance, and at the same time do not affect the properties after curing.

[0160] Add special functional additives, such as light stabilizers and antioxidants, to improve the aging resistance of the varnish and prevent problems such as yellowing and powdering after long-term use.

[0161] Adopt a dual-curing process combining UV curing and thermal curing. After applying the overprint varnish, first perform UV curing. Use ultraviolet light to initiate the photoinitiator in the coating to generate free radicals, so that the resin quickly crosslinks and cures to form a preliminary coating structure. Then, perform thermal curing. By heating, the remaining functional groups in the coating further react to complete the crosslinking and curing process, improving the final performance of the coating.

[0162] Example Five:

[0163] This example also proposes some design solutions that can be changed.

[0164] Optimization of primer material: Use an epoxy-modified acrylate primer, which has good adhesion and hardness and has good adaptability to various substrates such as metals and plastics. During the laser engraving process, it can withstand the energy impact of the laser and is not prone to primer peeling or cracking.

[0165] Personalization of the overprint varnish layer: Adjust the resin system, select resins with strong adhesion, good flexibility and excellent weather resistance, such as acrylic resins and polyurethane resins, or adopt resin compounding technology to improve the comprehensive performance of the overprint varnish layer.

[0166] Adjustment of laser engraving parameters: Introduce dynamic focusing technology to adjust the laser focal length in real time according to the laser engraving position to ensure that the laser engraving accuracy and effect are consistent at different positions, especially suitable for automotive parts with complex curved surfaces. Use galvanometer scanning technology to quickly and accurately control the movement of the laser beam, improve the laser engraving speed and flexibility, and achieve efficient laser engraving of complex patterns.

[0167] Optimization of topcoat material: Improve the hardness and wear resistance of the varnish, add fillers such as nano-scale silica and alumina to enhance the scratch resistance of the varnish.

[0168] It should be noted that the above examples are only used to illustrate the technical solutions of the present invention and are not restrictive. 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 spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A coating for multi-coating color laser engraving of automobile accessories, characterized in that: It includes the following specific components: primer, color coating, topcoat; The primer comprises epoxy modified acrylate, nano silicon dioxide, plasticizer, photoinitiator, diluent, dispersant and leveling agent; The color layer comprises polyurethane resin, nano-scale color paste, light stabilizer, diluent, dispersant and defoamer; The topcoat comprises aliphatic polyurethane acrylate, reactive diluent, photoinitiator, light stabilizer and antioxidant.

2. The coating for multi-coating color laser engraving of automobile accessories according to claim 1, characterized in that: The primer includes the following parts by mass: Epoxy modified acrylate is 50-60 parts; Nano silicon dioxide is 5-10 parts; Plasticizer is 3-5 parts; Photoinitiator is 2-4 parts; The diluent is 20-30 parts; Dispersant is 1-2 parts; The leveling agent is 1-2 parts.

3. The coating for multi-coating color laser engraving of automobile accessories according to claim 1, characterized in that: The chromatic layer includes the following parts by mass: Polyurethane resin is 50-60 parts; Nano-scale color paste is 5-10 parts; Light stabilizer is 3-5 parts; The diluent is 20-30 parts; Dispersant is 1-2 parts; The defoaming agent is 1-2 parts.

4. The coating for multi-coating color laser engraving of automobile accessories according to claim 1, characterized in that: The topcoat includes the following parts by mass: Aliphatic polyurethane acrylate is 40-50 parts; The active diluent is 10-20 parts; Photoinitiator is 3-5 parts; Light stabilizer is 2-3 parts; The antioxidant is 0.5-1 part.

5. A method for preparing a coating for a multi-coat color laser engraving scheme for automobile accessories, which is prepared based on the coating for a multi-coat color laser engraving scheme for automobile accessories according to any one of claims 1 to 4, characterized in that: Including the preparation of primer, color layer and topcoat; When preparing the primer: Add nano silicon dioxide into the diluent and disperse it evenly; Add epoxy modified acrylate and stir; Add plasticizer, dispersant, photoinitiator in sequence, and finally add leveling agent, stir evenly to obtain primer; When preparing the color layer: Add nano-scale color paste to the diluent and grind it with a sand mill to control the particle size of the pigment to less than 100nm; Add polyurethane resin and stir; Add light stabilizer, dispersant and defoamer in sequence, stir evenly to obtain a color layer; When preparing the topcoat: Adding aliphatic polyurethane acrylate into the reactive diluent and stirring; Add photoinitiator, light stabilizer and antioxidant in sequence, continue stirring for 20-30 minutes to obtain topcoat.

6. The method for preparing coating for multi-coating color laser engraving of automobile accessories according to claim 5, characterized in that: The epoxy-modified acrylate comprises: Add epoxy resin and acrylic acid to the flask in proportion, stir until completely dissolved, add catalyst and inhibitor, continue stirring for 10 minutes, heat the oil bath to 80-90°C, turn on the condensation reflux device, and maintain this temperature for 3-4 hours; The temperature was lowered to 60°C, triethylamine was slowly added dropwise to neutralize the excess acid, the pH was adjusted to 6.5-7.5, a diluent was added, and insoluble impurities were removed by hot filtration; the solvent was removed by reduced pressure distillation to obtain epoxy-modified acrylate.

7. The method for preparing coating for multi-coating color laser engraving of automobile accessories according to claim 5, characterized in that: The aliphatic polyurethane acrylate, when prepared, comprises: Add the catalyst and inhibitor to the dehydrated polyol and stir evenly; then slowly drop the aliphatic diisocyanate, control the drop speed so that the reaction temperature does not exceed 80°C; after the drop addition is completed, react at 70-80°C for 2-3 hours; The reaction temperature is lowered to about 60°C, and hydroxy acrylate is slowly added dropwise, and the dropping speed is controlled so that the reaction temperature does not exceed 70°C; after the addition is completed, the reaction is continued at 60-70°C for 2-3 hours until the NCO content is reduced to undetectable level, thereby obtaining aliphatic polyurethane acrylate.

8. An application of a coating for a multi-coat color laser engraving scheme for automobile accessories, based on the application of the coating for a multi-coat color laser engraving scheme for automobile accessories according to any one of claims 1 to 4, characterized in that: Including the application of primer, color layer and topcoat; When applying the primer: Pre-treat the substrate; Spray the primer on the substrate and let it sit for 5-10 minutes; Curing in an oven at 80-120°C for 30 minutes to ensure that the coating is completely cross-linked, and then naturally cool to room temperature; When applying to a color layer: Choose a single color or gradient color scheme based on design requirements; Use rubbing or spraying to spray the color layer, and let it stand for 10 minutes after spraying; Cure in an oven at 80-100°C for 20-30 minutes to ensure the coating is cured, then cool naturally to room temperature; When applying topcoat: Apply the topcoat evenly by spraying or rolling; After spraying, it is placed in a UV curing device, where the topcoat is quickly cured by ultraviolet light to improve durability and scratch resistance.

9. The coating application of the multi-coat color laser engraving solution for automobile accessories according to claim 8 is characterized in that: The coating application also includes the application of laser, including surface treatment, equipment debugging, positioning and clamping, engraving operation, and laser engraving effect inspection.

10. The coating application of the multi-coat color laser engraving solution for automobile accessories according to claim 9, characterized in that: During the engraving operation, the pattern position is aligned, a CCD visual positioning system is used to ensure accurate engraving, a line-by-line scanning method is used to remove the color layer to expose the primer or substrate, and the focus and scanning times are adjusted to ensure that the depth of the laser engraving is 3-10 μm.

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