Automobile ornament wood grain color-changing paint and production process thereof

Abstract

The application relates to the technical field of paint, in particular to a wood grain color-changing paint for automobile ornaments and a production process thereof; the wood grain color-changing paint for automobile ornaments comprises a bottom layer paint, a colored layer paint and a surface layer paint; the bottom layer paint is made of water-based hydroxyl acrylic resin, nano calcium carbonate, nano cerium oxide, mica powder, an ultraviolet resistance agent, a dispersing agent, a curing agent and deionized water; the colored layer paint is made of water-based linseed oil resin, pigments, nano cellulose, water-based acrylic emulsion, n-butyl acetate and ethylene glycol ether; and the surface layer paint is made of water-based fluorocarbon resin, hydroxyl acrylic resin, a functional additive, a stabilizer, a leveling agent, a curing agent and deionized water; the wood grain color-changing paint for automobile ornaments produced by the application not only has excellent anti-aging performance and antibacterial performance, but also has good wear resistance, effectively guarantees the quality, and prolongs the service life.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a wood grain color-changing coating for automotive trim and its production process. Background Technology

[0002] With the continuous development of the automotive industry, consumers' demands for the aesthetics, comfort, and personalization of car interiors are increasing. Solid wood and wood-look trim, due to their unique natural texture and warm feel, are widely used in interior components such as dashboards, door panels, and center consoles to enhance the overall luxury and sophistication of the vehicle. However, automotive interior components face extremely harsh operating environments, including high-temperature exposure, low-temperature freezing, high humidity, and frequent ultraviolet radiation. This places extremely high demands on the weather resistance, yellowing resistance, adhesion, and aesthetics of the wood-look trim surface coating.

[0003] Currently, automotive interior wood grain coatings mainly use solvent-based polyurethane or acrylic systems. These systems release large amounts of volatile organic compounds (VOCs) during application, posing a threat to the environment and the health of workers. With increasingly stringent environmental regulations, water-based coatings have become an inevitable trend in the industry, but existing water-based wood grain coatings still have many shortcomings in performance.

[0004] Firstly, at the primer level, the surface of wood (especially solid wood or artificial wood veneer) has natural pores. Differences in porosity in different areas can lead to uneven penetration of subsequent coatings, resulting in significant color variations and affecting the decorative effect. Current technologies often fail to completely solve this problem with simple sealing primers and require multiple coats, increasing costs.

[0005] Secondly, regarding the coloring layer, traditional colorants typically use solvents as carriers, resulting in rapid drying and a short application window. This makes it difficult for operators to evenly apply the color to the wood grain channels within a short time, easily leading to uneven coloring and blurred wood grain. Furthermore, the rapid evaporation of solvents also results in high VOC emissions, which is detrimental to environmental protection.

[0006] Finally, at the topcoat level, water-based resins generally have inferior weather resistance, scratch resistance, and antibacterial properties compared to solvent-based resins. For example, due to the relatively poor film density of water-based resins, the paint film is prone to yellowing, chalking, and loss of gloss under long-term ultraviolet radiation. Furthermore, the interior environment of a car is a breeding ground for bacteria and mold; coatings lacking antibacterial properties will foster microbial growth after prolonged use, affecting in-car air quality and even posing health risks.

[0007] Based on the above description, the present invention provides a wood grain color-changing coating for automotive trim and its manufacturing process to solve the aforementioned technical problems. Summary of the Invention

[0008] The purpose of this invention is to provide a wood grain color-changing coating for automotive trim and its production process. The produced wood grain color-changing coating for automotive trim not only has excellent anti-aging and antibacterial properties, but also has good wear resistance, effectively ensuring its quality and extending its service life to a certain extent.

[0009] A wood grain color-changing coating for automotive trim includes a base coat, a coloring layer coat, and a top coat coat; wherein... The underlying coating is made from the following raw materials in parts by weight: 60-85 parts waterborne hydroxyl acrylic resin, 15-25 parts nano calcium carbonate, 6-12 parts nano cerium oxide, 2-5 parts mica powder, 1-3 parts UV stabilizer, 1-2 parts dispersant, 20-25 parts first curing agent, and 10-15 parts deionized water. The coloring coating is made from the following raw materials in parts by weight: 35-50 parts water-based linseed oil resin, 25-35 parts pigment, 5-8 parts nanocellulose, 12-18 parts water-based acrylic emulsion, 20-25 parts n-butyl acetate and 5-8 parts ethylene glycol ethyl ether. The topcoat is made from the following raw materials in parts by weight: 60-75 parts waterborne fluorocarbon resin, 20-30 parts hydroxyl acrylic resin, 5-8 parts functional additives, 1-3 parts stabilizer, 1-2 parts leveling agent, 20-25 parts secondary curing agent, and 10-15 parts deionized water.

[0010] Furthermore, the pigment is selected from any one of iron oxide yellow, titanium nickel yellow, iron oxide red, iron oxide green, iron oxide orange, and cobalt blue.

[0011] Furthermore, the UV protectant is selected from any one of UV-320, UV-531, UV-326, UV-234, UV-327, and UV-328.

[0012] Furthermore, the dispersant is selected from any one of BYK-190, AFCONA4530, and EDAPLAN490.

[0013] Furthermore, the stabilizer is selected from any one of Tinuvin 622, Tinuvin 400, Tinuvin 292, Tinuvin 400, and Tinuvin 5060.

[0014] Furthermore, the leveling agent is selected from any one of BYK-300, BYK-310, BYK-320, BYK-333, BYK-346, and TEGO450.

[0015] Furthermore, the preparation method of the functional additive includes the following steps: Step 1: Disperse the spherical substrate uniformly in an ethanol aqueous solution with a volume concentration of 80-85% at a dosage ratio of 20-50 g / L. Then add 0.8-1.2 times the mass of the spherical substrate and react at 70-80℃ for 4-6 hours. After that, filter, wash, and vacuum dry and grind the reaction solution to obtain the pretreated spherical substrate. Step 2: Dissolve chitosan fully in an aqueous solution of acetic acid with a concentration of 0.5-0.8 wt% and a mass of 15-20 times that of chitosan. Then add pretreated spherical substrate with a mass of 0.2-0.5 times that of chitosan. Stir and react at 40-60℃ for 2-4 hours. Then filter, wash and vacuum dry the reaction solution to obtain the functional additive. The aqueous solution of acetic acid contains 6-10 wt% dialcyldimethylammonium chloride.

[0016] Furthermore, the preparation method of the spherical substrate includes the following steps: cetylamine, 0.08-0.12 mol / L potassium chloride solution, deionized water and ethanol are mixed evenly, and isopropyl titanate with a volume of 4-6 times that of potassium chloride solution is added at 800-1200 r / min at 25-30℃. After standing for 15-20 h, the reaction solution is centrifuged, washed with ethanol, vacuum dried and sintered in sequence to obtain the spherical substrate. The ratio of cetylamine, potassium chloride solution, deionized water and ethanol used is (0.6-1)g:(0.3-0.5)mL:(0.4-0.6)mL:(100-150)mL.

[0017] Furthermore, the vacuum drying temperature is 40-60℃ and the drying time is 10-15h; the sintering temperature is 450-550℃ and the sintering time is 2-3h.

[0018] A production process for a wood grain color-changing coating for automotive trim includes the following steps: Step 1: Preparation of the base coat: Water-based hydroxyl acrylic resin and deionized water are mixed evenly, then nano calcium carbonate, nano cerium oxide and mica powder are added and evenly dispersed. The remaining raw materials are then added and evenly emulsified to obtain the base coat. Step 2: Preparation of coloring layer coating: Mix water-based linseed oil resin and pigment evenly, then add the remaining raw materials, and emulsify evenly to obtain the coloring layer coating; Step 3: Preparation of topcoat: Mix water-based fluorocarbon resin and hydroxyl acrylic resin evenly, then add the remaining raw materials, and emulsify evenly to obtain the topcoat.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses isopropyl titanate, cetylamine, and potassium chloride as raw materials to prepare nano-titanium dioxide with high specific surface area and porous structure, i.e., spherical substrates, via a sol-gel method. Subsequently, the spherical substrates are surface-modified with α-aminopropyltrimethoxysilane to introduce amino functional groups, enabling them to chemically bond with chitosan. The pretreated spherical substrates with amino groups are uniformly dispersed in a chitosan-acetic acid solution containing dialcyldimethylammonium chloride. As a natural polymer, the amino groups on chitosan's molecular chain react with the silane coupling agent on the surface of the pretreated substrate, thereby firmly coating the spherical substrate surface with a chitosan shell, forming a composite functional additive with spherical titanium dioxide as the core and chitosan as the shell. Simultaneously, the chitosan shell effectively encapsulates and fixes the dialcyldimethylammonium chloride adsorbed on the surface of the spherical substrate, allowing it to synergistically interact with the nano-titanium dioxide and chitosan to improve antibacterial properties. The functional additive prepared in this invention plays multiple roles in topcoats. First, the spherical titanium dioxide core acts as a UV shield, absorbing and scattering ultraviolet rays to prevent yellowing and aging of the paint film. Furthermore, the synergistic effect of chitosan, nano-titanium dioxide, and dialcyldimethylammonium chloride gives the prepared functional additive excellent antibacterial properties.

[0020] 2. This invention, by constructing a multi-layer coating system of primer-coloring layer-topcoat, synergistically solves the shortcomings of traditional wood grain color-changing coatings in terms of color difference control, application window, and weather resistance, greatly expanding its application prospects in the automotive interior field. Specifically, the base coat uses water-based hydroxyl acrylic resin, compounded with nano-calcium carbonate, nano-cerium oxide, and mica powder. The synergistic effect of nano-calcium carbonate and nano-cerium oxide, combined with the layered structure of mica powder, effectively seals the uneven penetration caused by differences in porosity on the wood surface, thereby significantly controlling and reducing color difference. The coloring layer uses water-based linseed oil resin as a carrier, compounded with nano-cellulose. Utilizing the excellent thixotropic properties of nano-cellulose, the open time of the colorant can be extended, providing more ample time for wiping and touch-up, resulting in more uniform coloring and clearer wood grain contrast. The topcoat achieves a good balance between hardness and flexibility through the compounding of water-based fluorocarbon resin and hydroxyl acrylic resin. At the same time, the combination of functional additives and stabilizers greatly improves the antibacterial properties, UV aging resistance and wear resistance of the paint film, ensuring that automotive interior parts can maintain their lasting beauty and stable performance even after long-term use and in complex environments.

[0021] In summary, the wood grain color-changing coating for automotive trim produced by this invention not only has excellent anti-aging and antibacterial properties, but also good wear resistance, effectively ensuring its quality while extending its service life to a certain extent. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] The aqueous hydroxyl acrylic resin used in the following examples and comparative examples was purchased from Shenzhen Haide New Material Technology Co., Ltd., with the product number XTN-5365; The water-based linseed oil resin is PA350 water-based linseed oil resin from Dongguan Jielu Chemical Technology Co., Ltd. The waterborne fluorocarbon resin was purchased from Shanghai Dongfu Chemical Technology Co., Ltd., model number DF-300. Hydroxyacrylate resin is a copolymer of hydroxyacrylates, with a solid content of 59-62% and a specific gravity of 0.95-1.05 g / cm³. 3 The viscosity is 5500-6500cp (25℃), the acid value is 5-12mgKOH / g (100%), and the hydroxyl value is 53-56mgKOH / g; The first curing agent is an aqueous isocyanate curing agent, purchased from Covestro Polymers (China) Co., Ltd., product code BayhydurXP 2655; The second curing agent is BASF curing agent Basonat HI190B / S.

[0024] Example 1

[0025] A wood grain color-changing coating for automotive trim includes a base coat, a coloring layer coat, and a top coat coat; wherein... The base coat is made from the following raw materials in parts by weight: 60 parts water-based hydroxyl acrylic resin, 15 parts nano calcium carbonate, 6 parts nano cerium oxide, 2 parts mica powder, 1 part UV stabilizer UV-320, 1 part dispersant BYK-190, 20 parts first curing agent and 10 parts deionized water; The coloring coating is made from the following raw materials in parts by weight: 35 parts water-based linseed oil resin, 25 parts iron oxide yellow, 5 parts nanocellulose, 12 parts water-based acrylic emulsion, 20 parts n-butyl acetate and 5 parts ethylene glycol ethyl ether. The topcoat is made from the following raw materials in parts by weight: 60 parts waterborne fluorocarbon resin, 20 parts hydroxyl acrylic resin, 5 parts functional additives, 1 part stabilizer Tinuvin 622, 1 part leveling agent BYK-300, 20 parts second curing agent and 10 parts deionized water.

[0026] The preparation method of functional additives includes the following steps: Step 1: Disperse the spherical substrate uniformly in an 80% ethanol aqueous solution at a dosage ratio of 20 g / L, then add 0.8 times the mass of the spherical substrate of -aminopropyltrimethoxysilane, react at 70℃ for 6 h, and then filter, wash, and vacuum dry and grind the reaction solution to obtain the pretreated spherical substrate. Step 2: Dissolve chitosan fully in an aqueous solution of acetic acid with a concentration of 0.5 wt% and a mass of 15 times that of chitosan. Then add a pretreated spherical substrate with a mass of 0.2 times that of chitosan. Stir and react at 40°C for 4 hours. Then filter, wash and vacuum dry the reaction solution to obtain the functional additive. The aqueous solution of acetic acid contains 6 wt% dialcyldimethylammonium chloride.

[0027] The preparation method of the spherical substrate includes the following steps: cetylamine, 0.08 mol / L potassium chloride solution, deionized water and ethanol are mixed evenly, and isopropyl titanate with a volume of 4 times that of potassium chloride solution is added at 800 r / min at 25℃. After standing for 15 h, the reaction solution is centrifuged, washed with ethanol, vacuum dried and sintered in sequence to obtain the spherical substrate. The ratio of cetylamine, potassium chloride solution, deionized water and ethanol used is 0.6g:0.3mL:0.4mL:100mL. The vacuum drying temperature is 40℃ and the drying time is 15h; the sintering temperature is 450℃ and the sintering time is 3h.

[0028] A production process for a wood grain color-changing coating for automotive trim includes the following steps: Step 1: Preparation of the base coat: Water-based hydroxyl acrylic resin and deionized water are mixed evenly, then nano calcium carbonate, nano cerium oxide and mica powder are added and evenly dispersed. The remaining raw materials are then added and evenly emulsified to obtain the base coat. Step 2: Preparation of coloring layer coating: Mix water-based linseed oil resin and pigment evenly, then add the remaining raw materials, and emulsify evenly to obtain the coloring layer coating; Step 3: Preparation of topcoat: Mix water-based fluorocarbon resin and hydroxyl acrylic resin evenly, then add the remaining raw materials, and emulsify evenly to obtain the topcoat.

[0029] Example 2

[0030] A wood grain color-changing coating for automotive trim includes a base coat, a coloring layer coat, and a top coat coat; wherein... The base coat is made from the following raw materials in parts by weight: 75 parts water-based hydroxyl acrylic resin, 20 parts nano calcium carbonate, 10 parts nano cerium oxide, 3 parts mica powder, 2 parts UV stabilizer UV-531, 2 parts dispersant AFCONA4530, 25 parts first curing agent and 15 parts deionized water. The coloring coating is made from the following raw materials in parts by weight: 40 parts water-based linseed oil resin, 30 parts iron oxide red, 6 parts nanocellulose, 15 parts water-based acrylic emulsion, 20 parts n-butyl acetate and 6 parts ethylene glycol ethyl ether. The topcoat is made from the following raw materials in parts by weight: 70 parts waterborne fluorocarbon resin, 25 parts hydroxyl acrylic resin, 6 parts functional additives, 2 parts stabilizer Tinuvin 400, 1 part leveling agent BYK-310, 25 parts secondary curing agent and 10 parts deionized water.

[0031] The preparation method of functional additives includes the following steps: Step 1: Disperse the spherical substrate uniformly in an 85% ethanol aqueous solution at a dosage ratio of 40g / L, then add α-aminopropyltrimethoxysilane in an equal mass to the spherical substrate, react at 75℃ for 5h, and then filter, wash, and vacuum dry and grind the reaction solution to obtain the pretreated spherical substrate. Step 2: Dissolve chitosan fully in an aqueous solution of acetic acid with a concentration of 0.6 wt% and a mass of 20 times that of chitosan. Then add a pretreated spherical substrate with a mass of 0.4 times that of chitosan. Stir the reaction at 50°C for 3 hours. Then filter, wash and vacuum dry the reaction solution to obtain the functional additive. The aqueous solution of acetic acid contains 8 wt% dialcyldimethylammonium chloride.

[0032] The preparation method of the spherical substrate includes the following steps: cetylamine, 0.1 mol / L potassium chloride solution, deionized water and ethanol are mixed evenly, and isopropyl titanate with a volume of 5 times that of potassium chloride solution is added at 30°C and stirred at 1000 r / min. After standing for 20 h, the reaction solution is centrifuged, washed with ethanol, vacuum dried and sintered in sequence to obtain the spherical substrate. The ratio of cetylamine, potassium chloride solution, deionized water and ethanol used is 0.8g:0.4mL:0.5mL:150mL. The vacuum drying temperature is 50℃ and the drying time is 10h; the sintering temperature is 500℃ and the sintering time is 2h.

[0033] A production process for a wood grain color-changing coating for automotive trim includes the following steps: Step 1: Preparation of the base coat: Water-based hydroxyl acrylic resin and deionized water are mixed evenly, then nano calcium carbonate, nano cerium oxide and mica powder are added and evenly dispersed. The remaining raw materials are then added and evenly emulsified to obtain the base coat. Step 2: Preparation of coloring layer coating: Mix water-based linseed oil resin and pigment evenly, then add the remaining raw materials, and emulsify evenly to obtain the coloring layer coating; Step 3: Preparation of topcoat: Mix water-based fluorocarbon resin and hydroxyl acrylic resin evenly, then add the remaining raw materials, and emulsify evenly to obtain the topcoat.

[0034] Example 3

[0035] A wood grain color-changing coating for automotive trim includes a base coat, a coloring layer coat, and a top coat coat; wherein... The base coat is made from the following raw materials in parts by weight: 85 parts water-based hydroxyl acrylic resin, 25 parts nano calcium carbonate, 12 parts nano cerium oxide, 5 parts mica powder, 3 parts UV stabilizer UV-326, 2 parts dispersant EDAPLAN490, 25 parts first curing agent and 15 parts deionized water. The coloring coating is made from the following raw materials in parts by weight: 50 parts water-based linseed oil resin, 35 parts iron oxide orange, 8 parts nanocellulose, 18 parts water-based acrylic emulsion, 25 parts n-butyl acetate and 8 parts ethylene glycol ethyl ether. The topcoat is made from the following raw materials in parts by weight: 75 parts waterborne fluorocarbon resin, 30 parts hydroxyl acrylic resin, 8 parts functional additives, 3 parts stabilizer Tinuvin 292, 2 parts leveling agent BYK-320, 25 parts secondary curing agent and 15 parts deionized water.

[0036] The preparation method of functional additives includes the following steps: Step 1: Disperse the spherical substrate uniformly in an 85% ethanol aqueous solution at a dosage ratio of 50 g / L, then add 1.2 times the mass of the spherical substrate of -aminopropyltrimethoxysilane, react at 80℃ for 4 h, and then filter, wash, and vacuum dry and grind the reaction solution to obtain the pretreated spherical substrate. Step 2: Dissolve chitosan fully in an aqueous solution of acetic acid with a concentration of 0.8 wt% and a mass of 20 times that of chitosan. Then add a pretreated spherical substrate with a mass of 0.5 times that of chitosan. Stir the reaction at 60°C for 2 hours. Then filter, wash and vacuum dry the reaction solution to obtain the functional additive. The aqueous solution of acetic acid contains 10 wt% dialcyldimethylammonium chloride.

[0037] The preparation method of the spherical substrate includes the following steps: cetylamine, 0.12 mol / L potassium chloride solution, deionized water and ethanol are mixed evenly, and isopropyl titanate with a volume of 6 times that of potassium chloride solution is added at 1200 r / min at 30℃. After standing for 20 h, the reaction solution is centrifuged, washed with ethanol, vacuum dried and sintered in sequence to obtain the spherical substrate. The ratio of cetylamine, potassium chloride solution, deionized water and ethanol used is 1g:0.5mL:0.6mL:150mL. The vacuum drying temperature is 60℃ and the drying time is 10h; the sintering temperature is 550℃ and the sintering time is 2h.

[0038] A production process for a wood grain color-changing coating for automotive trim includes the following steps: Step 1: Preparation of the base coat: Water-based hydroxyl acrylic resin and deionized water are mixed evenly, then nano calcium carbonate, nano cerium oxide and mica powder are added and evenly dispersed. The remaining raw materials are then added and evenly emulsified to obtain the base coat. Step 2: Preparation of coloring layer coating: Mix water-based linseed oil resin and pigment evenly, then add the remaining raw materials, and emulsify evenly to obtain the coloring layer coating; Step 3: Preparation of topcoat: Mix water-based fluorocarbon resin and hydroxyl acrylic resin evenly, then add the remaining raw materials, and emulsify evenly to obtain the topcoat.

[0039] Comparative Example 1: The difference between this comparative example and Example 1 is that the topcoat in this comparative example does not contain functional additives.

[0040] Comparative Example 2: The difference between this comparative example and Example 1 is that a spherical substrate is used in this comparative example instead of an equal amount of functional additives.

[0041] Comparative Example 3: The difference between this comparative example and Example 1 is that the aqueous acetic acid solution used in the preparation of the functional additive in this comparative example does not contain dialcyldimethylammonium chloride.

[0042] Performance testing The relevant properties of the wood grain color-changing coatings for automotive trim produced in Examples 1-3 and Comparative Examples 1-4 were tested respectively, and the experimental data are recorded in the table below: Adhesion (cross-cut test): According to GB / T9286-1998 standard, use a cross-cut tester to draw squares on the coating film, use 3M tape to pull it off, observe the coating film peeling off, and evaluate the grade (0 is the best, 5 is the worst).

[0043] Abrasion resistance: According to GB / T1768-2006 standard, use Taber abrasion tester (CS-10 grinding wheel, 1000g load, 500 rpm) to record the abrasion amount (mg).

[0044] 3. Yellowing resistance (QUV aging): According to GB / T23987-2009 standard, a QUV aging test chamber (UVA-340 lamp, irradiance 0.68W / m@340nm, light temperature 60℃, condensation temperature 50℃, cycle: 4h light exposure + 4h condensation) was used. After 1000h of testing, the E value (color difference value) was measured using a colorimeter. The smaller the E value, the better the yellowing resistance.

[0045] 4. Antibacterial properties: Antibacterial properties were tested according to GB 21551.2-2010 standard.

[0046] By comparing and analyzing the relevant data in the table, it can be seen that the wood grain color-changing coating for automotive trim produced by this invention not only has excellent anti-aging and antibacterial properties, but also good wear resistance, effectively ensuring its quality while extending its service life to a certain extent. This indicates that the wood grain color-changing coating for automotive trim and its production process provided by this invention have a broader market prospect and are more suitable for promotion.

[0047] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0048] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A wood grain color-changing coating for automotive trim, characterized in that, It includes a base coat, a color coat, and a top coat; among which, The underlying coating is made from the following raw materials in parts by weight: 60-85 parts waterborne hydroxyl acrylic resin, 15-25 parts nano calcium carbonate, 6-12 parts nano cerium oxide, 2-5 parts mica powder, 1-3 parts UV stabilizer, 1-2 parts dispersant, 20-25 parts first curing agent, and 10-15 parts deionized water. The coloring coating is made from the following raw materials in parts by weight: 35-50 parts water-based linseed oil resin, 25-35 parts pigment, 5-8 parts nanocellulose, 12-18 parts water-based acrylic emulsion, 20-25 parts n-butyl acetate and 5-8 parts ethylene glycol ethyl ether. The topcoat is made from the following raw materials in parts by weight: 60-75 parts waterborne fluorocarbon resin, 20-30 parts hydroxyl acrylic resin, 5-8 parts functional additives, 1-3 parts stabilizer, 1-2 parts leveling agent, 20-25 parts secondary curing agent, and 10-15 parts deionized water.

2. The wood grain color-changing coating for automotive trim according to claim 1, characterized in that: The pigment is selected from any one of iron oxide yellow, titanium nickel yellow, iron oxide red, iron oxide green, iron oxide orange, and cobalt blue.

3. The wood grain color-changing coating for automotive trim according to claim 1, characterized in that: The UV protectant is selected from any one of UV-320, UV-531, UV-326, UV-234, UV-327, and UV-328.

4. The wood grain color-changing coating for automotive trim according to claim 1, characterized in that: The dispersant is selected from any one of BYK-190, AFCONA4530, and EDAPLAN490.

5. The wood grain color-changing coating for automotive trim according to claim 1, characterized in that: The stabilizer is selected from any one of Tinuvin 622, Tinuvin 400, Tinuvin 292, Tinuvin 400, and Tinuvin 5060.

6. The wood grain color-changing coating for automotive trim according to claim 1, characterized in that: The leveling agent is selected from any one of BYK-300, BYK-310, BYK-320, BYK-333, BYK-346, and TEGO450.

7. The wood grain color-changing coating for automotive trim according to claim 1, characterized in that, The preparation method of the functional additive includes the following steps: Step 1: Disperse the spherical substrate uniformly in an ethanol aqueous solution with a volume concentration of 80-85% at a dosage ratio of 20-50 g / L. Then add 0.8-1.2 times the mass of the spherical substrate and react at 70-80℃ for 4-6 hours. After that, filter, wash, and vacuum dry and grind the reaction solution to obtain the pretreated spherical substrate. Step 2: Dissolve chitosan fully in an aqueous solution of acetic acid with a concentration of 0.5-0.8 wt% and a mass of 15-20 times that of chitosan. Then add pretreated spherical substrate with a mass of 0.2-0.5 times that of chitosan. Stir and react at 40-60℃ for 2-4 hours. Then filter, wash and vacuum dry the reaction solution to obtain the functional additive. The aqueous solution of acetic acid contains 6-10 wt% dialcyldimethylammonium chloride.

8. The wood grain color-changing coating for automotive trim according to claim 7, characterized in that, The preparation method of the spherical substrate includes the following steps: Cetylamine, 0.08-0.12 mol / L potassium chloride solution, deionized water and ethanol are mixed evenly, and isopropyl titanate with a volume of 4-6 times that of potassium chloride solution is added at 800-1200 r / min at 25-30℃. After standing for 15-20 h, the reaction solution is centrifuged, washed with ethanol, vacuum dried and sintered in sequence to obtain the spherical substrate. The ratio of cetylamine, potassium chloride solution, deionized water and ethanol used is (0.6-1)g:(0.3-0.5)mL:(0.4-0.6)mL:(100-150)mL.

9. The wood grain color-changing coating for automotive trim according to claim 8, characterized in that: The vacuum drying temperature is 40-60℃, and the drying time is 10-15h; the sintering temperature is 450-550℃, and the sintering time is 2-3h.

10. A production process for a wood grain color-changing coating for automotive trim parts according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Preparation of the base coat: Water-based hydroxyl acrylic resin and deionized water are mixed evenly, then nano calcium carbonate, nano cerium oxide and mica powder are added and evenly dispersed. The remaining raw materials are then added and evenly emulsified to obtain the base coat. Step 2: Preparation of coloring layer coating: Mix water-based linseed oil resin and pigment evenly, then add the remaining raw materials, and emulsify evenly to obtain the coloring layer coating; Step 3: Preparation of topcoat: Mix water-based fluorocarbon resin and hydroxyl acrylic resin evenly, then add the remaining raw materials, and emulsify evenly to obtain the topcoat.

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