Anti-aging and acid and alkali resistant furniture coating and preparation method thereof

Abstract

The invention discloses an anti-aging and acid-alkali-resistant furniture coating and a preparation method thereof in the field of furniture coatings. The coating comprises an acrylic polyurethane copolymer, light-resistant and chemical-resistant synergistic modifiers A and B and the like. The modifier A is obtained by stirring specific raw materials in a solvent at room temperature under the protection of nitrogen, then carrying out heating reaction, reduced pressure distillation and other steps to prepare an intermediate, and further reacting the intermediate with catechol; the modifier B is prepared by carrying out heating reaction, extraction, pH regulation and other operations on corresponding raw materials to obtain an intermediate, then reacting the intermediate with sodium p-toluenesulfonate and purifying. When the coating is prepared, all the components are dispersed in a high-speed dispersion machine under the protection of nitrogen, then transferred to a sand mill to be sanded to the specified fineness, and finally filtered. Through the synergistic effect of the modifier, the coating has good aging resistance and acid and alkali resistance.

Description

Technical Field

[0001] This invention relates to the field of furniture coating technology, specifically to an anti-aging and acid / alkali resistant furniture coating and its preparation method. Background Art

[0002] As an important part of daily life and work environment, furniture's surface coating not only serves a decorative function but also directly affects the product's durability and lifespan. Traditional furniture coatings use synthetic resins such as polyurethane and acrylates as the main film-forming substances, forming a protective coating through physical film formation or chemical cross-linking, which can give furniture surfaces gloss, wear resistance, and a certain degree of stain resistance. However, during long-term use, furniture coatings are prone to performance degradation under complex environmental stresses, especially coating failure caused by photoaging and chemical corrosion, which has become a key technical bottleneck restricting the improvement of furniture quality.

[0003] From the perspective of photoaging mechanisms, ultraviolet (UV) radiation from the sun is the core trigger for the breakage of molecular chains in coatings. When UV radiation acts on traditional coatings, its energy is sufficient to break the chemical bonds in the polymer backbone, leading to the breakage of polymer chains and the generation of free radicals. These free radicals further trigger a chain reaction of oxidation, altering the chromophore structure in the coating, manifesting as yellowing, chalking, and a decrease in mechanical strength of the paint film. Simultaneously, oxygen and heat in the environment accelerate this process, creating a synergistic aging effect. For example, furniture placed near windows indoors or used outdoors often shows noticeable discoloration and roughening within months of prolonged UV exposure, severely impacting its aesthetics and protective function. Traditional solutions often rely on adding a single type of UV absorber or hindered amine light stabilizer. However, these additives only work on specific aging stages and lack a synergistic effect, making it difficult to form a comprehensive protective network, resulting in inevitable aging and failure of the coating after long-term use.

[0004] On the other hand, furniture frequently comes into contact with acidic and alkaline substances during daily cleaning and maintenance, further exacerbating the risk of chemical degradation of the coating. Acidic environments attack sensitive groups such as ester and urethane bonds in the coating, triggering hydrolysis reactions that generate small molecule products. Alkaline environments promote the oxidative degradation of polymer chains and the destruction of cross-linked structures, causing the coating to lose elasticity and adhesion. Traditional coatings, in order to balance cost and performance, typically add only a small amount of inert filler or simple acid-base neutralizers. However, these measures only provide temporary protection. When acidic or alkaline substances penetrate into the coating, the unmodified resin matrix still suffers irreversible chemical damage, manifesting as blistering, peeling, or even substrate corrosion. Especially in high-humidity environments such as kitchens and bathrooms where contact with chemical reagents is frequent, ordinary furniture coatings often require repainting within one to two years, increasing maintenance costs and causing resource waste and environmental pollution.

[0005] The aforementioned problems place higher demands on the performance of furniture coatings: they must enhance the coating's resistance to ultraviolet radiation and slow down photoaging through molecular-level modification; and they must also strengthen its chemical stability against acids and alkalis to block the penetration of corrosive media in the environment. However, existing technologies for improving anti-aging and acid / alkali resistance often employ physical mixing methods with added additives. These additives have poor compatibility with the resin matrix and are prone to migration, precipitation, or aggregation during long-term use, leading to a decline in protective effectiveness over time. Therefore, developing a novel modified compound that synergistically integrates light-stabilizing and chemical-resistant properties through chemical structure design and introducing it into the coating system to form a stable protective network has become a key breakthrough direction for solving the above problems. This invention is based on this technical requirement, and through the design of a novel modifier with dual-functional synergistic effects and optimization of the coating preparation process, it achieves a significant improvement in the anti-aging and acid / alkali resistance of furniture coatings. Summary of the Invention

[0006] The purpose of this invention is to provide an anti-aging and acid-alkali resistant furniture coating and its preparation method, which solves the technical problems of insufficient anti-aging and acid-alkali resistance of existing coatings, overcomes the defects of existing coatings such as easy photoaging, chemical corrosion leading to yellowing, chalking, and peeling, and improves the long-term stability and service life of the coating.

[0007] The present invention achieves the above objectives through the following technical solutions:

[0008] An anti-aging and acid / alkali resistant furniture coating comprises the following raw materials in parts by weight:

[0009] Acrylic polyurethane copolymer: 300-500 parts by weight;

[0010] Photo-chemical resistance synergistic modifier A: 5-20 parts by weight;

[0011] Photo-chemical resistance synergistic modifier B: 3-15 parts by weight;

[0012] Xylene: 100-200 parts by weight;

[0013] Propylene glycol methyl ether acetate: 100-150 parts by weight;

[0014] Dispersant: 5-15 parts by weight;

[0015] Defoamer: 1-3 parts by weight;

[0016] Leveling agent: 2-5 parts by weight;

[0017] Nano silica: 10-30 parts by weight;

[0018] Film-forming aid: 20-50 parts by weight;

[0019] The preparation method of the photo-chemical synergistic modifier A includes: A1. Under nitrogen protection, 4-hydroxy-3,5-di-tert-butylbenzoic acid and 1-ethyl-(3-dimethylaminopropyl)carbodiimide are added to dry N,N-dimethylformamide and stirred at room temperature; then N-hydroxysuccinimide is added and stirring is continued to form an active ester intermediate; then octadecylamine is added dropwise and the temperature is raised to 45-50℃ for reaction; after the reaction is completed, the mixture is distilled under reduced pressure, the residue is extracted with ethyl acetate, the organic phases are combined and washed with saturated brine, dried with anhydrous sodium sulfate and filtered, and the intermediate is obtained by rotary evaporation; A2. The intermediate and catechol are added to N,N-dimethylformamide, anhydrous K2CO3 is added, and the temperature is raised to 80-85℃ for reaction; after the reaction is completed, the mixture is cooled to room temperature, the mixture is slowly poured into ice water, the precipitated solid is collected by suction filtration, washed with deionized water until neutral; the crude product is recrystallized with ethanol and dried.

[0020] In this invention, the synthesis of the photo-chemical synergistic modifier A involves a multi-step chemical reaction to construct a molecular structure with synergistic effects of UV absorption and tertiary amine antioxidant activity. The core reaction is divided into two stages: the formation of an active ester intermediate and the functionalization of the tertiary amine. In the initial stage, the reaction system uses a dry polar aprotic solvent as the medium. Under nitrogen-free oxygen protection, a raw material containing benzotriazole structural units (hereinafter referred to as "benzotriazole derivative") and a highly reactive carbodiimide compound (hereinafter referred to as "carbodiimide") are first introduced. The molecular structure of carbodiimide contains a highly activated carbon-nitrogen double bond. During stirring at room temperature, its carbon atom can undergo a nucleophilic addition reaction with the oxygen atom in the carboxyl group of the benzotriazole derivative, forming an unstable intermediate state. This intermediate state rapidly transforms into an active ester intermediate through intramolecular rearrangement. This is a highly reactive ester compound whose carbonyl carbon atom exhibits stronger electrophilicity due to the electronic effect of the adjacent nitrogen atom, providing a key active site for subsequent steps. The purpose of room temperature stirring in this stage is to promote uniform dispersion of the raw materials and complete the initial intermolecular contact. The subsequently added compound containing a sulfonamide structure (hereinafter referred to as "sulfonamide") further undergoes a nucleophilic reaction with the active ester intermediate. The lone pair electrons on the nitrogen atom of the sulfonamide attack the carbonyl carbon of the active ester, forming a stable amide bond structure, ultimately constructing an active ester intermediate with a specific spatial configuration. This intermediate not only retains the UV absorption characteristics of the benzotriazole derivative (effectively shielding ultraviolet light in the 280-400 nm band) but also introduces the steric hindrance effect of the sulfonamide group, providing reaction sites for the subsequent incorporation of the tertiary amine segment. The key reaction in the second stage is the functionalization modification of the tertiary amine. The above-mentioned active ester intermediate is mixed with a raw material containing a long-chain aliphatic amine (hereinafter referred to as "aliphatic amine") in a polar aprotic solvent, and a weakly basic carbonate compound (hereinafter referred to as "carbonate") is added as an acid-binding agent. When the system is heated to a specific temperature range, the primary nitrogen atom in the aliphatic amine acts as a strong nucleophile, attacking the carbonyl carbon atom in the reactive ester intermediate. This carbon atom retains high electrophilic activity due to the electronic effect of the previous sulfonamide bond. After the nucleophilic addition reaction occurs, an unstable tetrahedral intermediate is first formed. Subsequently, by eliminating carbonate and reaction byproducts (such as small alcohol molecules), a stable amide bond structure is finally formed, introducing the long chain of the aliphatic amine into the molecular backbone. In this process, the role of carbonate is to neutralize the acidic byproducts generated in the reaction (such as protonated sulfonamides), maintain the alkaline environment of the reaction system, and thus accelerate the nucleophilic reaction.In the final modified agent A molecule structure, the benzotriazole derivative provides the ability to absorb ultraviolet light (by consuming ultraviolet energy through intramolecular electronic transitions, preventing it from causing polymer chain breakage), while the tertiary amine group (derived from aliphatic amines) serves as an antioxidant active center, which can interrupt the free radical chain reaction by providing lone pair electrons to react with free radicals (such as capturing peroxide free radicals and alkyl free radicals), thereby synergistically improving the stability of the coating in light and oxidative environments.

[0021] According to a preferred embodiment of the present invention, the acrylic polyurethane copolymer was purchased from Wanhua Chemical Group Co., Ltd., and the product name is [not specified]. PU-2300.

[0022] According to a preferred embodiment of the present invention, the nitrogen gas is purchased from Air Liquide (China) Investment Co., Ltd., and is industrial-grade high-purity nitrogen gas (99.999%).

[0023] According to a preferred embodiment of the present invention, the 4-hydroxy-3,5-di-tert-butylbenzoic acid was purchased from Aladdin Reagent (Shanghai) Co., Ltd., and the product name is 4-hydroxy-3,5-di-tert-butylbenzoic acid standard.

[0024] According to a preferred embodiment of the present invention, the 1-ethyl-(3-dimethylaminopropyl)carbodiimide was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., and the product name was EDC·HCl (CAS No.: 1892-57-5).

[0025] According to a preferred embodiment of the present invention, the N,N-dimethylformamide was purchased from Sinopharm Chemical Reagent Co., Ltd., and the product was analytical grade DMF (CAS No.: 68-12-2).

[0026] According to a preferred embodiment of the present invention, the N-hydroxysuccinimide was purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd., model number NHS (CAS No.: 6066-82-6).

[0027] According to a preferred embodiment of the present invention, the octadecylamine was purchased from Nanjing Datang Chemical Co., Ltd., and the product name is octadecylamine (CAS No.: 124-30-1).

[0028] According to a preferred embodiment of the present invention, the ethyl acetate was purchased from Tianjin Damao Chemical Reagent Factory, and the product was analytical grade ethyl acetate (CAS No.: 141-78-6).

[0029] According to a preferred embodiment of the present invention, the saturated saline solution was purchased from Xilong Scientific Co., Ltd., and is a sodium chloride saturated aqueous solution (analytical grade).

[0030] According to a preferred embodiment of the present invention, the anhydrous sodium sulfate was purchased from Guangdong Guanghua Technology Co., Ltd., and the product is anhydrous sodium sulfate (CAS No.: 7757-82-6).

[0031] According to a preferred embodiment of the present invention, the catechol was purchased from Shanghai Yuanye Biotechnology Co., Ltd., and the product name is 1,2-dihydroxybenzene (CAS No.: 120-80-9).

[0032] According to a preferred embodiment of the present invention, the K2CO3 was purchased from Chengdu Kelong Chemical Co., Ltd., and the product is anhydrous potassium carbonate (CAS No.: 584-08-7).

[0033] According to a preferred embodiment of the present invention, the ethanol was purchased from Sinopharm Chemical Reagent Co., Ltd., and the product was analytical grade anhydrous ethanol (CAS No.: 64-17-5).

[0034] According to a preferred embodiment of the present invention, the xylene was purchased from China Petrochemical Corporation Jinling Petrochemical Co., Ltd., and the product type was industrial grade xylene (CAS No.: 1330-20-7).

[0035] According to a preferred embodiment of the present invention, the propylene glycol methyl ether acetate was purchased from Jiangsu Dena Chemical Co., Ltd., and its product name is PMAC (CAS No.: 88-89-1).

[0036] According to a preferred embodiment of the present invention, the dispersant is purchased from BYK Chemical Technology Consulting (Shanghai) Co., Ltd., and the model number is BYK-190.

[0037] According to a preferred embodiment of the present invention, the defoamer is purchased from BYK Chemical Technology Consulting (Shanghai) Co., Ltd., and the model number is BYK-052.

[0038] According to a preferred embodiment of the present invention, the leveling agent is purchased from BYK Chemical Technology Consulting (Shanghai) Co., Ltd., and the model number is BYK-333.

[0039] According to a preferred embodiment of the present invention, the nano-silica is purchased from Evonik Specialty Chemicals (Shanghai) Co., Ltd., and the product is [model number missing]. R972.

[0040] According to a preferred embodiment of the present invention, the film-forming aid is purchased from Eastman Chemical Company (China agent: Shanghai Yiqing Trading Co., Ltd.), and the product is [model number missing]. Alcohol ester twelve.

[0041] According to a preferred embodiment of the present invention, in step A1, the stirring time at room temperature is 30-40 min; the stirring time is continued for 20-40 min; and the reaction time is 12-14 h when the temperature is raised to 45-50°C.

[0042] According to a preferred embodiment of the present invention, in step A2, the reaction time is 18-20 hours after heating to 80-85°C.

[0043] According to a preferred embodiment of the present invention, the preparation method of the photo-chemical synergistic modifier B includes: B1, adding 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and epichlorohydrin to a dry three-necked flask equipped with a mechanical stirrer and a reflux condenser, then adding NaOH, and heating to 60-65°C for reaction; after the reaction is completed, cooling to room temperature, extracting the organic phase with dichloromethane, adjusting the pH of the aqueous phase to neutral with dilute hydrochloric acid, combining the organic phases, drying with anhydrous magnesium sulfate, filtering, and removing dichloromethane by rotary evaporation to obtain an intermediate; B2, adding the intermediate and sodium p-toluenesulfonate to acetone, then adding triethylamine, heating to 50-55°C for reaction, filtering after the reaction is completed, extracting the filtrate with ethyl acetate, combining the organic phases and washing with deionized water to neutral; purifying the crude product by silica gel column chromatography.

[0044] In this invention, the synthesis of photo-chemical synergistic modifier B involves an epoxy ring-opening reaction and a nucleophilic substitution reaction to construct a composite functional molecule containing a hindered phenolic structure and a sulfonic acid group. The reaction process can be divided into two key steps: epoxy group activation and nucleophilic addition modification. The core reaction in the initial stage is the ring-opening reaction of epichlorohydrin. In a closed reactor equipped with mechanical stirring and reflux condensation, a raw material containing a benzotriazole structure (hereinafter referred to as "phenolic derivative") is mixed with a chlorinated epoxy monomer (hereinafter referred to as "epoxy monomer"), and a strongly basic compound (hereinafter referred to as "base") is added. The base catalyzes the ring-opening of the epoxy ring in the epichlorohydrin molecule by abstracting a proton from the carbon atom bonded to the oxygen atom in the epoxy monomer (or directly attacking the carbon atom of the epoxy ring), releasing the stress on the epoxy ring and forming an activated ring-opening intermediate state. At this point, the hydroxyl oxygen atom (possessing a lone pair of electrons) in the phenolic derivative acts as a nucleophile, attacking the positively charged carbon atom in the ring-opening intermediate, resulting in a nucleophilic substitution reaction and forming a stable ether-linked structure. During this process, the addition of a base not only accelerates the ring-opening rate of the epoxy ring but also maintains the alkaline environment of the reaction system by neutralizing the hydrogen chloride (HCl) byproduct generated in the reaction, preventing the phenolic hydroxyl group from being protonated and reducing its nucleophilic activity. The reflux condenser maintains a stable reaction temperature and prevents the volatilization of low-boiling-point solvents, ensuring the reaction proceeds fully. After the reaction is complete, the organic phase (containing the target intermediate and unreacted raw materials) is extracted and separated using a polar solvent (hereinafter referred to as the "extractant"). The aqueous phase is adjusted to neutral with dilute acid to remove residual alkaline substances. Finally, after drying and solvent removal, an intermediate containing ether-linked bonds is obtained. The molecular skeleton of this intermediate retains both the benzene ring structure of the phenolic derivative (which can later be converted into a hindered phenolic antioxidant group) and the hydroxyl or chlorine atom introduced after the ring-opening of the epoxy monomer (as a subsequent reaction site). The key reaction in the second stage is the introduction and functionalization modification of sulfonic acid groups. The aforementioned intermediate is mixed with a raw material containing sulfonic acid groups (hereinafter referred to as "sulfonic acid raw material") in a polar solvent (hereinafter referred to as "reaction solvent"), and a tertiary amine compound with electron-donating effect (hereinafter referred to as "tertiary amine") is added as a catalyst. When the system is heated to a specific temperature range, the sulfonate ion (or sulfonyl chloride group) in the sulfonic acid raw material acts as an electrophile, competing with the hydrogen atoms at the ortho or para positions of the phenolic hydroxyl group in the intermediate. Under the catalysis of the tertiary amine, the oxygen atom of the phenolic hydroxyl group is first activated (forming an oxygen anion), which then attacks the electrophilic sites in the sulfonic acid raw material (such as the carbon atom of the sulfonyl chloride), forming a stable CO bond structure through nucleophilic substitution, thus introducing the sulfonic acid group into the molecular framework. In this process, the tertiary amine catalyst accelerates the incorporation rate of the sulfonic acid group by providing lone pairs of electrons to form coordination bonds with the reaction intermediate.In the final modified agent B molecule structure, the benzene ring of the phenolic derivative is functionalized to form a hindered phenolic structure (which inhibits the oxidation of phenolic hydroxyl groups through steric hindrance), which can effectively capture free radicals (such as peroxy free radicals). The sulfonic acid group provides additional polar sites, which enhances the compatibility between the molecule and the polymer matrix, and can stabilize the polymer chain segments through hydrogen bonding, thus synergistically improving the coating's tolerance in acidic and alkaline environments.

[0045] According to a preferred embodiment of the present invention, the three-necked flask was purchased from Shanghai Yuzhuo Instrument Co., Ltd., and is a 250mL glass three-necked flask (with reflux condenser and mechanical stirrer).

[0046] According to a preferred embodiment of the present invention, the 2-(2'-hydroxy-5'-methylphenyl)benzotriazole was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., and the product name is 2-(2H-benzotriazole-2-yl)-4-methylphenol (CAS No.: 2440-22-4).

[0047] According to a preferred embodiment of the present invention, the epichlorohydrin was purchased from China Petrochemical Corporation Jinling Petrochemical Co., Ltd., and is industrial grade epichlorohydrin (CAS No.: 106-89-8).

[0048] According to a preferred embodiment of the present invention, the NaOH was purchased from Xilong Scientific Co., Ltd., and the product was analytical grade sodium hydroxide (CAS No.: 1310-73-2).

[0049] According to a preferred embodiment of the present invention, the dichloromethane was purchased from Sinopharm Chemical Reagent Co., Ltd., and the product was analytical grade dichloromethane (CAS No.: 75-09-2).

[0050] According to a preferred embodiment of the present invention, the dilute hydrochloric acid was purchased from Guangdong Guanghua Technology Co., Ltd., and was an analytical grade hydrochloric acid solution (concentration of approximately 10%).

[0051] According to a preferred embodiment of the present invention, the magnesium sulfate was purchased from Tianjin Damao Chemical Reagent Factory, and the product is anhydrous magnesium sulfate (CAS No.: 7487-88-9).

[0052] According to a preferred embodiment of the present invention, the sodium p-toluenesulfonate was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., and the product name is sodium p-toluenesulfonate (CAS No.: 657-84-1).

[0053] According to a preferred embodiment of the present invention, the acetone was purchased from Tianjin Kemei Chemical Reagent Co., Ltd., and the product was analytical grade acetone (CAS No.: 67-64-1).

[0054] According to a preferred embodiment of the present invention, the triethylamine was purchased from Shanghai Yuanye Biotechnology Co., Ltd., and the product name is triethylamine (CAS No.: 121-44-8).

[0055] According to a preferred embodiment of the present invention, the ethyl acetate was purchased from Tianjin Damao Chemical Reagent Factory, and the product was analytical grade ethyl acetate (CAS No.: 141-78-6).

[0056] According to a preferred embodiment of the present invention, the silica gel column is purchased from Qingdao Ocean Chemical Co., Ltd., and is a 200-300 mesh silica gel column chromatography packing material (packing size: Ф10×200mm).

[0057] According to a preferred embodiment of the present invention, the high-speed disperser was purchased from Fluko Fluid Machinery Manufacturing Co., Ltd., and is a FLUKO FA25 high-shear dispersing emulsifier (with an adjustable speed of 800-1200 rpm).

[0058] According to a preferred embodiment of the present invention, the sand mill was purchased from Dongguan Langling Machinery Co., Ltd., and the model is LMZ-0.3L laboratory nano sand mill (equipped with 0.3-0.5mm zirconia beads).

[0059] According to a preferred embodiment of the present invention, the stainless steel filter screen is purchased from Shanghai Xinnuo Instrument Group Co., Ltd., and is a 200-210 mesh stainless steel plate and frame filter (equipped with 304 stainless steel filter screen).

[0060] According to a preferred embodiment of the present invention, in step B1, the reaction time is 8-10 hours after heating to 60-65°C.

[0061] According to a preferred embodiment of the present invention, in step B2, the reaction time is 15-20 hours after the temperature is raised to 50-55°C.

[0062] The present invention also provides a method for preparing the aforementioned anti-aging and acid-alkali resistant furniture coating, comprising the following steps:

[0063] S1. Acrylic polyurethane copolymer, photo-chemical synergistic modifier A, photo-chemical synergistic modifier B, xylene, propylene glycol methyl ether acetate, dispersant, defoamer, leveling agent, nano silica and film-forming aid are sequentially added to the sealed tank of a high-speed disperser and dispersed under nitrogen protection.

[0064] S2. Then the mixture is transferred to a sand mill, and the feeding speed and cooling temperature are controlled to grind it to a fineness of ≤15μm;

[0065] S3. Finally, filter with a stainless steel filter.

[0066] In this invention, the final performance of the anti-aging and acid-alkali resistant furniture coating is achieved through the synergistic effect of the acrylic polyurethane copolymer matrix and two modifiers. Its mechanism of action can be divided into three levels: UV protection, free radical capture, and acid-alkali neutralization. The acrylic polyurethane copolymer, as the main film-forming substance of the coating, contains a large number of sensitive groups such as ester groups and urethane bonds in its molecular chain, which are easily corroded by ultraviolet light, oxygen, and acids and alkalis. Under long-term light exposure, the unmodified copolymer will experience ester group breakage (generating free radicals and small molecule carboxylic acids), leading to coating film chalking and yellowing. In acidic or alkaline environments, urethane bonds are prone to hydrolysis (breaking to generate isocyanates and alcohols), destroying the cross-linked network of the coating film. The introduction of photo-chemical synergistic modifier A enhances the aging resistance of coatings through a dual mechanism: its benzotriazole structural unit can absorb more than 90% of ultraviolet light (especially high-energy ultraviolet light with wavelengths of 300-400nm), converting ultraviolet energy into harmless heat energy through intramolecular electronic transitions, thereby preventing the direct damage of ultraviolet light to the copolymer chain; the tertiary amine group acts as an active free radical scavenger, which can react with peroxy radicals (ROO·) and alkyl radicals (R·) generated during copolymer degradation (such as the tertiary amine nitrogen atom providing lone pair electrons to form a stable nitrogen radical intermediate with the free radical), interrupting the free radical chain reaction and delaying the oxidative aging process of the coating film. The addition of photo-chemical synergistic modifier B provides protection against acidic and alkaline environments: its hindered phenolic structure (with sterically hindered groups modifying the ortho / para positions of the hydroxyl groups on the benzene ring) preferentially captures peroxide free radicals (generating stable phenoxy free radicals), preventing free radicals from attacking the ester and urethane bonds in the copolymer chain; the sulfonic acid groups bind to the copolymer segments through hydrogen bonding, enhancing the polarity and density of the coating film, while neutralizing trace amounts of acidic substances in the environment (such as carbonic acid formed by carbon dioxide dissolving in water), slowing down the hydrolysis rate of urethane bonds by acidic media. Nano-silica, as an auxiliary filler, forms a three-dimensional network structure through physical dispersion in the coating film, further preventing ultraviolet penetration and improving the mechanical strength of the coating film; the film-forming aid optimizes the film-forming process of the copolymer, ensuring that the modifier is uniformly dispersed in the coating film, ultimately achieving a comprehensive performance improvement of the coating under long-term light exposure, high and low temperature cycling, and acid and alkaline exposure conditions.

[0067] According to a preferred embodiment of the present invention, in step S1, the rotation speed of the high-speed disperser is 800-1200 rpm, and the dispersion time is 15-20 min.

[0068] According to a preferred embodiment of the present invention, in step S2, the cooling temperature is ≤40°C.

[0069] According to a preferred embodiment of the present invention, in step S3, the material is filtered through a 200-210 mesh stainless steel filter.

[0070] The beneficial effects of the present invention are:

[0071] This invention significantly improves the anti-aging and acid / alkali resistance of furniture coatings through innovative molecular structure design and optimized preparation process, solving the performance degradation problem of traditional coatings caused by ultraviolet radiation and chemical corrosion during long-term use. Firstly, the light- and chemical-resistant synergistic modifiers A and B introduced into the coating, through a unique combination of chemical groups, block the key reaction pathways of aging and corrosion at the source. The hindered amine group in modifier A effectively captures free radicals induced by ultraviolet radiation, inhibiting the chain oxidation and breakage of polymer chains. Simultaneously, the catechol unit in its molecular structure can neutralize acidic substances, forming stable chemical bonds and preventing acid corrosion damage from extending into the coating interior. The octadecyl long chain forms a physical barrier through hydrophobic interaction, reducing the penetration rate of alkaline substances. The benzotriazole structure in modifier B selectively absorbs high-energy ultraviolet radiation and converts it into harmless heat energy, preventing photochemical reactions. The epoxy groups crosslink with the resin to form a three-dimensional network structure, significantly improving the coating's density and chemical stability. The sulfonate groups directly neutralize alkaline substances, preventing their erosion of the polymer backbone. The two modifiers form a uniformly dispersed synergistic system with the resin matrix through intermolecular hydrogen bonds, overcoming the defects of traditional additives such as easy migration and aggregation, and continuously exerting a protective effect during long-term use.

[0072] Secondly, the coating of this invention exhibits excellent durability in accelerated aging and chemical corrosion resistance tests, significantly extending the lifespan and maintenance cycle of furniture. Through the synergistic effect of modifiers A and B, the coating effectively inhibits yellowing and chalking under long-term ultraviolet irradiation, maintaining surface gloss and color stability, with significantly higher gloss retention and color fastness than traditional coatings. When exposed to acidic or alkaline cleaning agents or high-humidity environments, the coating demonstrates excellent chemical resistance, resisting ester bond hydrolysis caused by acidic substances and polymer chain oxidative degradation caused by alkaline substances, maintaining the integrity and adhesion of the coating, and preventing problems such as blistering, peeling, or substrate corrosion. This dual protection mechanism allows the coating to maintain stable protective performance under complex environmental conditions (such as kitchens, bathrooms, and outdoors), reducing the need for frequent furniture refurbishment due to coating failure, lowering maintenance costs and resource consumption, while simultaneously enhancing the user experience and product added value.

[0073] Finally, the preparation method of this invention achieves efficient integration of the modifier and coating system through precise control of reaction conditions and process parameters, ensuring stable reproducibility of product performance. The synthesis of modifiers A and B employs a stepwise reaction strategy, with strict control of temperature, time, and solvent to guarantee the purity of the target product and the effective retention of active groups. During coating preparation, high-speed dispersion and sand milling processes are optimized to ensure uniform dispersion of each component and achieve the required fineness, avoiding coating defects caused by particle agglomeration. This preparation method is mature, easy to operate, and suitable for large-scale industrial production. Furthermore, the raw material ratio and process parameters can be adjusted according to actual needs, flexibly adapting to different furniture types and environmental conditions. Through molecular-level modification design and innovative preparation processes, this invention not only improves the overall performance of furniture coatings but also provides a new solution for technological upgrading in the coating industry, possessing broad market application prospects and promotional value. Detailed Implementation

[0074] The following detailed embodiments are only used to further illustrate this application and should not be construed as limiting the scope of protection of this application. Those skilled in the art can make some non-essential improvements and adjustments to this application based on the above application content.

[0075] Example 1

[0076] An anti-aging and acid / alkali resistant furniture coating comprises 400g of acrylic polyurethane copolymer, 12g of light-chemical synergistic modifier A, 9g of light-chemical synergistic modifier B, 150g of xylene, 120g of propylene glycol methyl ether acetate, 10g of dispersant, 2g of defoamer, 3g of leveling agent, 20g of nano-silica, and 35g of film-forming aid; wherein the raw materials for preparing light-chemical synergistic modifier A include 45g of 4-hydroxy-3,5-di-tert-butylbenzoic acid, 38g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 35g of N-hydroxysuccinimide, 52g of octadecylamine, 350g of N,N-dimethylformamide, 40g of catechol, and anhydrous K2CO3. 38g; The raw materials for preparing the photo-chemical synergistic modifier B include 42g of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 38g of epichlorohydrin, 12g of NaOH, 280g of dichloromethane, 38g of sodium p-toluenesulfonate, 250g of acetone, and 22g of triethylamine; The preparation steps for the anti-aging and acid-alkali resistant furniture coating are as follows: S1, add the acrylic polyurethane copolymer, photo-chemical synergistic modifier A, photo-chemical synergistic modifier B, xylene, propylene glycol methyl ether acetate, dispersant, defoamer, leveling agent, nano silica, and film-forming aid to the sealed tank of a high-speed disperser in sequence, and disperse at 1000 rpm for 18 min under nitrogen protection; S2, then transfer the mixture to a sand mill, control the feed rate and cooling temperature, and sand mill to a fineness of 13μm. The cooling temperature is 38℃; S3, finally filtered through a 205-mesh stainless steel filter; the preparation steps of the light-chemical synergistic modifier A are as follows: A1, under nitrogen protection, 45g of 4-hydroxy-3,5-di-tert-butylbenzoic acid and 38g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide are added to 350g of dried N,N-dimethylformamide, stirred at room temperature (25±2℃) for 35min, then 35g of N-hydroxysuccinimide is added and stirred for another 30min to form an active ester intermediate, then 52g of octadecylamine is added dropwise, the temperature is raised to 48℃ and the reaction is carried out for 13h, after the reaction is completed, N,N-dimethylformamide is removed by vacuum distillation (45℃, -0.09MPa), the residue is extracted twice with ethyl acetate (about 200mL), the organic phases are combined and washed three times with saturated brine (10% NaCl solution), dried with anhydrous sodium sulfate for 24h and filtered, and then rotary evaporated (40℃, -0.09MPa).08MPa) to obtain the intermediate; A2, add the intermediate and 40g of catechol to 350g of N,N-dimethylformamide, add 38g of anhydrous K2CO3, heat to 83℃ and react for 19h. After the reaction is completed, cool to room temperature (25±2℃), slowly pour the mixture into an ice-water mixture (500mL), collect the precipitated solid by suction filtration through a Buchner funnel, wash with deionized water (4℃) until the pH of the filtrate is 7 (neutral), recrystallize the crude product with ethanol (volume is 3 times the mass of the crude product) for 2h, cool to room temperature and filter again, and dry; The preparation steps of the light-chemical resistance synergistic modifier B are as follows: B1, in a dry three-necked flask equipped with a mechanical stirrer (speed 50-100rpm) and a reflux condenser (the upper end is connected to a CaCl2 drying tube), add 42g of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and 38g of epichlorohydrin, and then add NaOH. 12g (pre-ground into powder) was placed in a three-necked flask in an oil bath and heated to 63℃ for 9 hours. During the reaction, reflux was carried out through a condenser to prevent solvent evaporation. After the reaction was completed, the mixture was naturally cooled to room temperature. The mixture was transferred to a separatory funnel and the organic phase was extracted with 280g of dichloromethane (the extraction was repeated 3 times and the results were combined). The pH of the aqueous phase was adjusted to 7-8 (neutral) with dilute hydrochloric acid (1mol / L), and the remaining organic phase was extracted again with dichloromethane and the results were combined. The organic phase was dried over anhydrous magnesium sulfate for 24 hours and then filtered. The dichloromethane was removed by rotary evaporation (40℃, -0.08MPa) to obtain the intermediate. B2. The intermediate was reacted with 38g of sodium p-toluenesulfonate. Add 250g of acetone and 22g of triethylamine. Seal the reaction system and heat to 53℃ for 18 hours. After the reaction, allow it to cool naturally to room temperature. First, filter through filter paper to remove insoluble salt impurities. Extract the filtrate twice with 200g of ethyl acetate to remove residual polar impurities. Combine the organic phases and wash with deionized water until neutral (pH=7). Transfer the crude product to a silica gel column chromatography apparatus (stationary phase: 200-300 mesh silica gel; mobile phase: ethyl acetate: petroleum ether = 1:3). After purification by gradient elution, collect the target component and concentrate under reduced pressure (40℃, -0.08MPa) to obtain the photo-chemical resistance synergistic modifier B.

[0077] Example 2

[0078] The specific implementation method is the same as in Example 1, except that an anti-aging and acid-alkali resistant furniture coating includes 350g of acrylic polyurethane copolymer, 8g of light-chemical synergistic modifier A, 6g of light-chemical synergistic modifier B, 120g of xylene, 110g of propylene glycol methyl ether acetate, 8g of dispersant, 1g of defoamer, 2g of leveling agent, 15g of nano silica, and 25g of film-forming aid; wherein the raw materials for preparing light-chemical synergistic modifier A include 38g of 4-hydroxy-3,5-di-tert-butylbenzoic acid, 32g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 30g of N-hydroxysuccinimide, 45g of octadecylamine, 300g of N,N-dimethylformamide, 35g of catechol, and anhydrous K2CO3. 32g; The raw materials for preparing the photo-chemical resistance synergistic modifier B include 36g of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 32g of epichlorohydrin, and NaOH. 10g, dichloromethane 240g, sodium p-toluenesulfonate 32g, acetone 220g, triethylamine 18g; the preparation steps of the anti-aging and acid and alkali resistant furniture coating are as follows: S1, add acrylic polyurethane copolymer, photo-chemical synergistic modifier A, photo-chemical synergistic modifier B, xylene, propylene glycol methyl ether acetate, dispersant, defoamer, leveling agent, nano silica and film-forming aid to the sealed tank of a high-speed disperser in sequence, and disperse at 800 rpm for 15 min under nitrogen protection; S2, then transfer the mixture to a sand mill, control the feed rate and cooling temperature, and sand mill to a fineness of 12μm, cooling temperature 35℃; S3, finally filter through a 200-mesh stainless steel filter; the preparation steps of photo-chemical synergistic modifier A are as follows: A1, under nitrogen protection, 4-hydroxy-3 5-Di-tert-butylbenzoic acid and 1-ethyl-(3-dimethylaminopropyl)carbodiimide were added to dry N,N-dimethylformamide and stirred at room temperature for 30 min. Then, N-hydroxysuccinimide was added and stirring was continued for 20 min to form an active ester intermediate. Octadecylamine was then added dropwise, and the mixture was heated to 45 °C and reacted for 12 h. After the reaction was completed, the mixture was distilled under reduced pressure, and the residue was extracted with ethyl acetate. The organic phases were combined and washed with saturated brine. After drying with anhydrous sodium sulfate, the mixture was filtered and rotary evaporated to obtain the intermediate. A2. The intermediate and catechol were added to N,N-dimethylformamide, and anhydrous K2CO3 was added. The mixture was heated to 80 °C and reacted for 18 h. After the reaction was completed, the mixture was cooled to room temperature and poured very slowly into ice water. The precipitated solid was collected by suction filtration, washed with deionized water until neutral, and the crude product was recrystallized from ethanol and dried.The preparation steps of the photo-chemical synergistic modifier B are as follows: B1. In a dry three-necked flask equipped with a mechanical stirrer and a reflux condenser, 2-(2'-hydroxy-5'-methylbenzyl)benzotriazole and epichlorohydrin are added, followed by NaOH. The mixture is heated to 60℃ and reacted for 8 hours. After the reaction is complete, it is cooled to room temperature, and the organic phase is extracted with dichloromethane. The aqueous phase is adjusted to neutral pH with dilute hydrochloric acid, and the organic phases are combined. After drying with anhydrous magnesium sulfate, the mixture is filtered, and dichloromethane is removed by rotary evaporation to obtain the intermediate. B2. The intermediate and sodium p-toluenesulfonate are added to acetone, followed by triethylamine. The mixture is heated to 50℃ and reacted for 15 hours. After the reaction is complete, the mixture is filtered, and the filtrate is extracted with ethyl acetate. The organic phases are combined and washed with deionized water until neutral. The crude product is purified by silica gel column chromatography.

[0079] Example 3

[0080] The specific implementation method is the same as in Example 1, except that an anti-aging and acid-alkali resistant furniture coating includes 480g of acrylic polyurethane copolymer, 18g of light-chemical synergistic modifier A, 13g of light-chemical synergistic modifier B, 180g of xylene, 140g of propylene glycol methyl ether acetate, 14g of dispersant, 3g of defoamer, 5g of leveling agent, 28g of nano silica, and 45g of film-forming aid; wherein the raw materials for preparing light-chemical synergistic modifier A include 52g of 4-hydroxy-3,5-di-tert-butylbenzoic acid, 45g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 42g of N-hydroxysuccinimide, 60g of octadecylamine, 400g of N,N-dimethylformamide, 45g of catechol, and anhydrous K2CO3. 42g; The raw materials for preparing the photo-chemical synergistic modifier B include 48g of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 42g of epichlorohydrin, 14g of NaOH, 300g of dichloromethane, 42g of sodium p-toluenesulfonate, 280g of acetone, and 25g of triethylamine; The preparation steps for the anti-aging and acid-alkali resistant furniture coating are as follows: S1, add the acrylic polyurethane copolymer, photo-chemical synergistic modifier A, photo-chemical synergistic modifier B, xylene, propylene glycol methyl ether ester, dispersant, defoamer, leveling agent, nano silica, and film-forming aid to the sealed tank of a high-speed disperser in sequence, and disperse at 1200 rpm for 20 min under nitrogen protection; S2, then transfer the mixture to a sand mill, control the feed rate and cooling temperature, and sand mill to a fineness of 14μm, with a cooling temperature of 39℃; S3, finally filter through a 210-mesh stainless steel filter; among which the photo-chemical synergistic modifier B... The preparation steps of the synergistic modifier A are as follows: A1. Under nitrogen protection, 4-hydroxy-3,5-di-tert-butylbenzoic acid and 1-ethyl-(3-dimethylaminopropyl)carbodiimide are added to dry N,N-dimethylformamide and stirred at room temperature for 40 min. Then, N-hydroxysuccinimide is added and stirring is continued for 40 min to form an active ester intermediate. Octadecylamine is then added dropwise, and the temperature is raised to 50℃ for 14 h. After the reaction is completed, the mixture is distilled under reduced pressure, and the residue is extracted with ethyl acetate. The organic phases are combined and washed with saturated brine. After drying with anhydrous sodium sulfate, the mixture is filtered and rotary evaporated to obtain the intermediate. A2. The intermediate and catechol are added to N,N-dimethylformamide, and anhydrous K2CO3 is added. The temperature is raised to 85℃ for 20 h. After the reaction is completed, the mixture is cooled to room temperature and slowly poured into ice water. The precipitated solid is collected by suction filtration, washed with deionized water until neutral, and the crude product is recrystallized with ethanol and dried.The preparation steps of the photo-chemical synergistic modifier B are as follows: B1. In a dry three-necked flask equipped with a mechanical stirrer and a reflux condenser, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and epichlorohydrin are added, followed by NaOH. The mixture is heated to 65℃ and reacted for 10 hours. After the reaction is complete, it is cooled to room temperature. The organic phase is extracted with dichloromethane. The pH of the aqueous phase is adjusted to neutral with dilute hydrochloric acid, and the organic phases are combined. After drying with anhydrous magnesium sulfate, the mixture is filtered, and dichloromethane is removed by rotary evaporation to obtain the intermediate. B2. The intermediate and sodium p-toluenesulfonate are added to acetone, followed by triethylamine. The mixture is heated to 55℃ and reacted for 20 hours. After the reaction is complete, the mixture is filtered, and the filtrate is extracted with ethyl acetate. The organic phases are combined and washed with deionized water until neutral. The crude product is purified by silica gel column chromatography.

[0081] Comparative Example 1

[0082] The specific implementation method is the same as in Example 1, except that a furniture coating includes 400g of acrylic polyurethane copolymer, 150g of xylene, 120g of propylene glycol methyl ether acetate, 10g of dispersant, 2g of defoamer, 3g of leveling agent, 20g of nano silica, and 35g of film-forming aid. The preparation steps of the anti-aging and acid and alkali resistant furniture coating are as follows: S1, the acrylic polyurethane copolymer, xylene, propylene glycol methyl ether acetate, dispersant, defoamer, leveling agent, nano silica and film-forming aid are added sequentially to the sealed tank of a high-speed disperser and dispersed at 1000 rpm for 18 minutes under nitrogen protection; S2, the mixture is then transferred to a sand mill, the feed rate and cooling temperature are controlled, and the mixture is sand-milled to a fineness of 13μm and cooled to 38℃; S3, finally filtered through a 205-mesh stainless steel filter.

[0083] Comparative Example 2

[0084] The specific implementation method is the same as in Example 1, except that a furniture coating includes 400g of acrylic polyurethane copolymer, 12g of light-chemical synergistic modifier A, 150g of xylene, 120g of propylene glycol methyl ether acetate, 10g of dispersant, 2g of defoamer, 3g of leveling agent, 20g of nano silica, and 35g of film-forming aid; wherein the raw materials for preparing light-chemical synergistic modifier A include 45g of 4-hydroxy-3,5-ditert-benzoic acid, 38g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, 35g of N-hydroxysuccinimide, 52g of octadecylamine, 350g of N,N-dimethylformamide, 40g of catechol, and anhydrous K2CO3. 38g; The preparation steps of the photo-chemical synergistic modifier A are as follows: A1. Under nitrogen protection, 4-hydroxy-3,5-ditert-benzoic acid and 1-ethyl-(3-dimethylaminopropyl)carbodiimide are added to dry N,N-dimethylformamide and stirred at room temperature for 35 min. Then, N-hydroxysuccinylimide is added and stirring is continued for 30 min to form an active ester intermediate. Octadecylamine is then added dropwise, and the temperature is raised to 48℃ and reacted for 13 h. After the reaction is completed, the mixture is distilled under reduced pressure, and the residue is extracted with ethyl acetate. The organic phases are combined and washed with saturated brine. After drying with anhydrous sodium sulfate, the mixture is filtered and rotary evaporated to obtain the intermediate; A2. The intermediate and catechol are added to N,N-dimethylformamide, anhydrous K2CO3 is added, and the temperature is raised to 83℃ and reacted. After 19 hours of reaction, cool to room temperature and slowly pour the mixture into ice water. Collect the precipitated solid by suction filtration, wash with deionized water until neutral, recrystallize the crude product with ethanol, and dry. The preparation steps of the anti-aging and acid-alkali resistant furniture coating are as follows: S1, add acrylic polyurethane copolymer, light-chemical synergistic modifier A, xylene, propylene glycol methyl ether acetate, dispersant, defoamer, leveling agent, nano silica and film-forming aid to the sealed tank of a high-speed disperser in sequence, and disperse at 1000 rpm for 18 min under nitrogen protection; S2, then transfer the mixture to a sand mill, control the feed rate and cooling temperature, and sand mill to a fineness of 13 μm, cooling temperature 38℃; S3, finally filter through a 205 mesh stainless steel filter.

[0085] Comparative Example 3

[0086] The specific implementation method is the same as in Example 1, except that a furniture coating includes 400g of acrylic polyurethane copolymer, 9g of light-chemical synergistic modifier B, 150g of xylene, 120g of propylene glycol methyl ether acetate, 10g of dispersant, 2g of defoamer, 3g of leveling agent, 20g of nano silica, and 35g of film-forming aid; wherein the raw materials for preparing light-chemical synergistic modifier B include 42g of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 38g of epichlorohydrin, and NaOH. 12g, dichloromethane 280g, sodium p-toluenesulfonate 38g, acetone 250g, triethylamine 22g; the preparation steps of the photo-chemical resistance synergistic modifier B are as follows: B1, in a dry three-necked flask equipped with a mechanical stirrer and a reflux condenser, add 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and epichlorohydrin, then add NaOH, heat to 63℃ and react for 9h. After the reaction is completed, cool to room temperature, extract the organic phase with dichloromethane, adjust the pH of the aqueous phase to neutral with dilute hydrochloric acid, combine the organic phases, dry with anhydrous magnesium sulfate, filter, and remove dichloromethane by rotary evaporation to obtain the intermediate; B2, add the intermediate and sodium p-toluenesulfonate to acetone, then add triethylamine, heat to 53℃ and react for 18 hours. h, after the reaction is complete, filter, extract the filtrate with ethyl acetate, combine the organic electrodes and wash with deionized water until neutral, and purify the crude product by silica gel column chromatography; the preparation steps of the anti-aging and acid and alkali resistant furniture coating are as follows: S1, add acrylic polyurethane copolymer, light-chemical synergistic modifier B, xylene, propylene glycol methyl ether acetate, dispersant, defoamer, leveling agent, nano silica and film-forming aid to the sealed tank of high-speed disperser in sequence, and disperse at 1000 rpm for 18 min under nitrogen protection; S2, then transfer the mixture to a sand mill, control the feed rate and cooling temperature, and sand mill to a fineness of 13 μm, cooling temperature 38℃; S3, finally filter through a 205 mesh stainless steel filter.

[0087] Performance testing

[0088] The furniture coatings prepared in Examples 1-3 and Comparative Examples 1-3 were applied to the surface of tinplate (120mm × 50mm × 0.2mm) according to GB / T 1727-1992 "General Method for Preparation of Coating Film". The dry film thickness was controlled at (50±5)μm. After curing at room temperature for 7 days, the performance was tested according to the following test methods:

[0089] 1. Aging resistance test: According to GB / T 1865-2009 "Artificial climate aging and artificial radiation exposure (filtered xenon arc radiation) of paints and varnishes", the accelerated aging test of the coating film was carried out using a xenon lamp aging test chamber (wavelength range 290-800nm, black panel temperature 65±3℃, relative humidity 50±5%, light / condensation cycle of 18h light / 4h condensation) for a test cycle of 1000h. After the aging test, the color difference (ΔE) of the coating surface was measured using a colorimeter (accuracy ΔE≤0.1). The microstructure of the coating surface was observed by scanning electron microscopy (SEM) and the chalking grade was recorded (graded according to GB / T 1766-2008 "Rating Method for Aging of Paint and Varnish Coatings", grade 0 is no chalking and grade 5 is severe chalking). At the same time, a pencil hardness tester (according to GB / T 6739-2006 "Determination of Hardness of Paint and Varnish Film by Pencil Method") was used to test the change in coating hardness (expressed as the hardness retention rate before and after aging, hardness retention rate = pencil hardness grade after aging / initial pencil hardness grade × 100%).

[0090] 2. Acid and Alkali Resistance Tests: For acid resistance testing, a 5% sulfuric acid solution (pH≈0.3) was used; for alkali resistance testing, a 5% sodium hydroxide solution (pH≈14) was used. The cured coating test panels were immersed in these solutions at (25±1)℃ for 72 hours. After immersion, the test panels were removed, rinsed with deionized water, and allowed to air dry. The coating surface was observed for defects such as blistering, peeling, and discoloration (rated according to GB / T1763-1979 "Determination of Chemical Resistance of Coatings," with grade 0 indicating no abnormalities and grade 5 indicating severe damage). The contact angle between the coating surface and water was measured using a contact angle meter (accuracy ±0.1°). The initial contact angle was the measured value of the un-immersed coating; the contact angle after immersion was used to assess changes in hydrophobic properties.

[0091] 3. Mechanical property testing: According to GB / T 1732-1993 "Determination of impact resistance of paint film", the impact resistance of the coating film is tested using a paint film impactor (dropping weight 1kg, impact height 50cm) (expressed as the maximum impact height without cracks or peeling of the coating film); according to GB / T 9286-1998 "Cross-cut test of paint and varnish film", the adhesion of the coating film is tested using a cross-cut tester (1mm spacing) (graded according to GB / T 9286-1998, grade 0 is that the cut edge is completely smooth and no squares are peeled off, grade 5 is that all squares are peeled off).

[0092] 4. Performance test results:

[0093] Table 1: Performance test results of each embodiment and comparative example

[0094]

[0095]

[0096] As shown in Table 1, the anti-aging and acid-alkali resistant furniture coatings prepared in Examples 1-3 of this invention, by simultaneously adding photo-chemical synergistic modifiers A and B, significantly solve the technical problems of insufficient anti-aging and acid-alkali resistance in existing coatings. They overcome the defects of traditional coatings caused by photoaging and chemical corrosion during long-term use, such as yellowing, chalking, and peeling, and greatly improve the long-term stability and service life of the coating. From the test results, in terms of aging resistance, Examples 1-3 showed a color difference (ΔE) of only 1.2-2.0 (slight discoloration) after 1000 hours of xenon lamp aging, far lower than the 6.8-8.5 (significant yellowing) of Comparative Examples 1-3, and maintained a chalking level of 0 (no chalking), while Comparative Examples 1-3 all showed levels 2-3 (slight chalking). Meanwhile, the hardness retention rate was as high as 96.8%-98.5%, significantly higher than the 85.3%-88.1% of Comparative Examples 1-3, indicating that the photo-chemical synergistic modifiers... The 4-hydroxy-3,5-di-tert-butylbenzoic acid structure in synergistic modifier A effectively absorbs ultraviolet light, preventing yellowing and chalking caused by polymer chain breakage induced by ultraviolet light. The tertiary amine group, by capturing free radicals, interrupts the chain reaction, delaying the decrease in hardness caused by oxidative aging. Regarding acid and alkali resistance, Examples 1-3 showed no bubbling or peeling (Grade 0) after immersion in 5% sulfuric acid and 5% sodium hydroxide solutions for 72 hours, while Comparative Examples 1-3 showed slight bubbling (Grade 2) and localized peeling (Grade 3). The coating exhibited varying degrees of damage, including localized discoloration (level 2), and an increased surface contact angle of 4.8-5.5° (enhanced hydrophobicity), which was superior to the 2.5-3.3° decrease in contact angle (enhanced hydrophilicity) observed in Comparative Examples 1-3. This indicates that the hindered phenolic structure generated from the reaction of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole with epichlorohydrin in the photo-chemical synergistic modifier B can capture free radicals and inhibit oxidative corrosion. Furthermore, the sulfonic acid groups enhance the coating's density and neutralize acidic and alkaline media through hydrogen bonding, effectively blocking acid and alkali corrosion. The components affect the hydrolysis and erosion of polymer segments. Regarding mechanical properties, Examples 1-3 exhibited an impact resistance of 50-55 cm (no cracks, no peeling) and an adhesion grade of 0 (completely smooth cut edges, no cell peeling), significantly superior to Comparative Examples 1-3's 40-45 cm (slight edge cracks) and grades 1-2 (a small number of cells peeling). This indicates that the synergistic effect of the two modifiers not only enhances the coating's resistance to environmental aging but also strengthens the bond strength between the coating and the substrate, as well as its overall mechanical properties. In contrast, Comparative Example 1, without any modifier, showed rapid yellowing, blistering, and peeling under photo-aging and acid / alkali corrosion. Comparative Example 2, with only the addition of photo-chemical synergistic modifier A, could inhibit yellowing and hardness reduction caused by UV aging to some extent, but could not effectively prevent localized damage caused by acid / alkali corrosion. Comparative Example 3, with only the addition of photo-chemical synergistic modifier B, provided some protection against acidic and alkaline environments, but lacked UV protection, leading to easy photo-aging and chalking of the coating, and limited improvement in mechanical properties.Therefore, Examples 1-3, through the synergistic effect of photo-chemical resistant modifiers A and B, comprehensively solved the problem of coating performance degradation caused by ultraviolet radiation and chemical media erosion in the long-term use of existing coatings, and significantly improved the durability and reliability of furniture coatings in practical applications.

[0097] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A furniture coating that is anti-aging and resistant to acids and alkalis, characterized in that, Including the following parts by weight of raw materials: Acrylic polyurethane copolymer: 300-500 parts by weight; Photo-chemical resistance synergistic modifier A: 5-20 parts by weight; Photo-chemical resistance synergistic modifier B: 3-15 parts by weight; Xylene: 100-200 parts by weight; Propylene glycol methyl ether acetate: 100-150 parts by weight; Dispersant: 5-15 parts by weight; Defoamer: 1-3 parts by weight; Leveling agent: 2-5 parts by weight; Nano silica: 10-30 parts by weight; Film-forming aid: 20-50 parts by weight; The preparation method of the photo-chemical synergistic modifier A includes: A1. Under nitrogen protection, 4-hydroxy-3,5-di-tert-butylbenzoic acid and 1-ethyl-(3-dimethylaminopropyl)carbodiimide are added to dry N,N-dimethylformamide and stirred at room temperature; then N-hydroxysuccinimide is added and stirring is continued to form an active ester intermediate; then octadecylamine is added dropwise and the temperature is raised to 45-50℃ for reaction; after the reaction is completed, the mixture is distilled under reduced pressure, the residue is extracted with ethyl acetate, the organic phases are combined and washed with saturated brine, dried with anhydrous sodium sulfate and filtered, and the intermediate is obtained by rotary evaporation; A2. The intermediate and catechol are added to N,N-dimethylformamide, anhydrous K2CO3 is added, and the temperature is raised to 80-85℃ for reaction; after the reaction is completed, the mixture is cooled to room temperature, the mixture is slowly poured into ice water, the precipitated solid is collected by suction filtration, washed with deionized water until neutral; the crude product is recrystallized with ethanol and dried.

2. The anti-aging and acid / alkali resistant furniture coating according to claim 1, characterized in that, In step A1, the stirring time at room temperature is 30-40 min; the stirring time is continued for 20-40 min; and the reaction time is 12-14 h when the temperature is raised to 45-50℃.

3. The anti-aging and acid / alkali resistant furniture coating according to claim 1, characterized in that, In step A2, the temperature is raised to 80-85℃ and the reaction time is 18-20 hours.

4. The anti-aging and acid / alkali resistant furniture coating according to claim 1, characterized in that, The preparation method of the photo-chemical synergistic modifier B includes: B1, adding 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and epichlorohydrin to a dry three-necked flask equipped with a mechanical stirrer and a reflux condenser, then adding NaOH, and heating to 60-65℃ for reaction; after the reaction is completed, cooling to room temperature, extracting the organic phase with dichloromethane, adjusting the pH of the aqueous phase to neutral with dilute hydrochloric acid, combining the organic phases, drying with anhydrous magnesium sulfate, filtering, and removing dichloromethane by rotary evaporation to obtain the intermediate; B2, adding the intermediate and sodium p-toluenesulfonate to acetone, then adding triethylamine, heating to 50-55℃ for reaction, filtering after the reaction is completed, extracting the filtrate with ethyl acetate, combining the organic phases and washing with deionized water to neutral; purifying the crude product by silica gel column chromatography.

5. The anti-aging and acid / alkali resistant furniture coating according to claim 4, characterized in that, In step B1, the temperature is raised to 60-65℃ and the reaction time is 8-10 hours.

6. The anti-aging and acid / alkali resistant furniture coating according to claim 4, characterized in that, In step B2, the temperature is raised to 50-55℃ and the reaction time is 15-20 hours.

7. A method for preparing an anti-aging and acid-alkali resistant furniture coating according to any one of claims 1-6, characterized in that, step include: S1. Acrylic polyurethane copolymer, photo-chemical synergistic modifier A, photo-chemical synergistic modifier B, xylene, propylene glycol methyl ether acetate, dispersant, defoamer, leveling agent, nano silica and film-forming aid are sequentially added to the sealed tank of a high-speed disperser and dispersed under nitrogen protection. S2. Then the mixture is transferred to a sand mill, and the feeding speed and cooling temperature are controlled to grind it to a fineness of ≤15μm; S3. Finally, filter with a stainless steel filter.

8. The preparation method according to claim 7, characterized in that, In step S1, the rotation speed of the high-speed disperser is 800-1200 rpm, and the dispersion time is 15-20 min.

9. The preparation method according to claim 7, characterized in that, In step S2, the cooling temperature is ≤40℃.

10. The preparation method according to claim 7, characterized in that, In step S3, the filter is passed through a 200-210 mesh stainless steel filter.

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