Anti-oxidation formula and preparation method of macaron color pencil coating

Abstract

The invention discloses an antioxidant formula of a macaron-color pencil coating and a preparation method, and particularly relates to the field of antioxidant pencil coatings. The water-based paint is prepared from water-based acrylic resin, water-based polyurethane resin, rutile type titanium dioxide, silane coupling agent surface modified nano diatomite, a natural plant extract, an ultraviolet light absorber, a dispersing agent and water-based environment-friendly color paste. The nano diatomite is ground and subjected to surface modification, so that the dispersion stability of the nano diatomite in a resin system is improved, and through the synergistic effect of plant extracts such as green tea, grape seeds and rosemary and an ultraviolet light absorber, oxidation fading of the coating under natural illumination and air conditions is effectively inhibited. The method comprises the steps of base paste dispersing, resin mixing, color paste blending, plant extract dissolving, vacuum defoaming and the like, the prepared coating has the advantages of being soft in color, high in stability, excellent in oxidation resistance and the like, and the durability and appearance retentivity of a macaron color pencil coating can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of antioxidant pencil coatings, and in particular to an antioxidant formulation and preparation method for macaron-colored pencil coatings. Background Technology

[0002] The field of pencil coating formulation technology encompasses the research and application of chemical materials such as coatings, pigments, and additives, primarily involving the design and optimization of coatings for pencils. The core of this technology includes studying how to improve pencil performance, such as color, hardness, gloss, and durability, by adjusting the coating formulation. In addition, the environmental friendliness and production cost of pencil coatings are also important aspects of this field. The antioxidant, UV-resistant, and abrasion-resistant properties of the coating are also key technical requirements for improving the quality of pencil coatings. In recent years, with the increasing demand for personalization and environmental protection, pencil coating design has begun to focus on innovation and multifunctionality.

[0003] Most existing coatings for pencil surfaces use water-based or solvent-based resin systems to meet environmental and safety requirements. Light-colored macaron-style coatings require high hiding power, durability, and resistance to yellowing, but common water-based systems are prone to yellowing, fading, and surface wear under long-term use or UV exposure, affecting the pencil's appearance and lifespan.

[0004] Patent CN116904047B addresses the problem of easy oxidation and slagging of anode carbon blocks used in aluminum electrolysis at high temperatures. It provides an environmentally friendly coating primarily made from electrolytic cell covering material, using anode material powder derived from electrolytic waste. The core of this coating lies in the recycling of electrolytic waste, obtaining low-iron anode material powder which is then mixed with phosphoric acid, aluminum hydroxide, and other ingredients to form the coating. This coating forms a dense protective layer at high temperatures, effectively isolating oxygen, and can melt and participate in the reaction at electrolysis temperatures without affecting the electrolysis process. It extends the anode's lifespan, utilizes waste resources, is low-cost, and has good environmental compatibility.

[0005] Patent CN116462997B addresses the oxidation protection of silicon steel during high-temperature heating. Its main components are fused magnesia, calcium aluminate cement, anhydrous sodium carbonate, and blast furnace slag, completely eliminating the use of chromium-containing materials to avoid environmental pollution. This coating forms a stable layer at high temperatures, exhibiting strong adhesion, resistance to cracking, and easy peeling after cooling. It reduces oxidation loss of silicon steel by more than 75%, with costs only 30% of similar products on the market. This invention offers strong high-temperature stability, is environmentally friendly, and low-cost, making it suitable for high-temperature protection in the steel industry.

[0006] Patent CN109294298A discloses an anti-oxidation coating for high-temperature steel and its preparation method, belonging to the field of high-temperature protective coating technology. This coating is based on an inorganic binder and contains components such as bauxite, chromium oxide, high-purity magnesia, feldspar, industrial aluminum powder, and functional additives. Through optimized proportioning and ball milling, it is produced as a water-based coating with a fineness of less than 30 micrometers. This coating is suitable for heat treatment environments of 1000–1250℃ and features simple application, low cost, and wide adaptability.

[0007] To address the aforementioned issues, a water-based coating formulation is needed that maintains the soft visual appeal of macaron colors while also providing good coverage, abrasion resistance, UV resistance, and antioxidant properties. Furthermore, the formulation should be simple, environmentally friendly, and easy to industrialize. Therefore, this solution proposes an antioxidant formulation and preparation method for macaron-colored pencil coatings to address these problems. Summary of the Invention

[0008] The main objective of this invention is to provide an antioxidant formulation and preparation method for macaron-colored pencil coatings, which can effectively solve the problem of high requirements for hiding power, durability and anti-yellowing properties of macaron-colored coatings.

[0009] To achieve the above objectives, the technical solution adopted by the present invention mainly includes the following steps: An antioxidant formulation for macaron-colored pencil paint comprises the following components by weight: Preferably, the composition includes 30-40 parts waterborne acrylic resin, 15-20 parts waterborne polyurethane resin, 10-15 parts nano-grade diatomaceous earth, 1-3 parts natural plant extracts, 1-2 parts ultraviolet absorber, 0.5-1.5 parts antioxidant, 10-20 parts titanium dioxide, 0.1-2.0 parts waterborne environmentally friendly color paste, 0.2-0.5 parts defoamer, 1-3 parts dispersant, and 30-35 parts deionized water.

[0010] More preferably, the titanium dioxide is rutile titanium dioxide.

[0011] Preferably, the dispersant is a 5-10% aqueous solution of sodium polycarboxylate dispersant, wherein the sodium polycarboxylate dispersant content accounts for 3.0-8.0% of the total solid weight.

[0012] Preferably, the nano-sized diatomaceous earth has a particle size of 50–200 nm and a specific surface area of ​​200–500 m². 2 / g and the surface is chemically modified with epoxy silane or methacryloxy silane.

[0013] Preferably, the natural plant extract is one of green tea extract, grape seed extract, rosemary extract, olive leaf extract, and tea tree essential oil extract, with a purity of 80-95%, and all extracts have undergone decolorization treatment.

[0014] More preferably, the natural plant extract is encapsulated by β-cyclodextrin.

[0015] Preferably, the water-based environmentally friendly color paste is any one or more of water-based red, water-based green, and water-based blue pigments mixed with titanium dioxide to form a macaron color system.

[0016] Preferably, the ultraviolet absorber is one of the following: emulsion-type hydroxyphenyl triazine ultraviolet absorber, UV-1215, UV-400, and UV-5151.

[0017] Preferably, the solvent for the natural plant extract includes: a solvent composed of 3-8 parts deionized water, 2-6 parts propylene glycol, and 0.05-0.2 parts AMP-95 capable of dissolving either green tea extract or olive leaf extract; a solvent composed of 3-7 parts propylene glycol, 2-5 parts propylene glycol methyl ether, and 0.5-1.5 parts polysorbate-20 capable of dissolving grape seed extract; a solvent composed of 2-4 parts propylene glycol butyl ether, 4-7 parts propylene glycol, 1.5-3 parts polysorbate-80, and 0.5-1.5 parts deionized water capable of dissolving rosemary extract; and a solvent composed of 2-4 parts propylene glycol butyl ether, 3-6 parts propylene glycol, 3-6 parts polysorbate-80, and 0.5-1.5 parts deionized water capable of dissolving tea tree essential oil extract.

[0018] Preferably, the antioxidant is one of water-soluble vitamin E derivatives, hydrogenated dibenzothiophene, and vanillin.

[0019] A method for preparing an antioxidant formulation for macaron-colored pencil paint includes the following steps: S1: Mix and disperse 60-80% of the formula amount of deionized water, defoamer, pretreated nano-sized diatomaceous earth, titanium dioxide and dispersant at 2000-3000 rpm for 15-20 min to obtain a stable white base slurry. S2: Mix the water-based acrylic resin and water-based polyurethane resin in the formula amount and add them to the white base slurry of S1 to form a resin mixture. Reduce the stirring speed to 1000-1200 rpm and disperse for 10-15 min. Add water-based environmentally friendly color paste and the remaining deionized water. Continue to disperse at 25-35℃ for 30-40 min to obtain the base color paint. S3: Dissolve the natural plant extract in the formula with the solvent, add it to the base paint, and stir magnetically at 25-30℃ for 5-10 minutes. Add the UV absorber and antioxidant in the formula, mix and stir at 300-600 rpm for 8-12 minutes under vacuum to remove bubbles. Let it stand for 24 hours without any layering to obtain macaron-colored pencil paint.

[0020] Preferably, the pretreatment step of nano-sized diatomaceous earth in step S1 is as follows: wash the untreated diatomaceous earth with deionized water 2-3 times, grind it with 0.6-1.0 mm zirconia beads at room temperature for 4-6 hours, add 0.5-2% epoxy silane or methacryloxy silane and react for 2-4 hours, then dry it for later use to obtain nano-sized diatomaceous earth.

[0021] More preferably, the macaron-colored pencil coatings prepared in the above steps can be used as the outer coating of wooden pencils.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. This solution modifies the surface and micronizes diatomaceous earth filler, combined with rutile titanium dioxide and water-based color paste, to improve the hiding power of the coating while maintaining the soft appearance of the macaron light color series. Combined with plant extracts, antioxidants and UV absorbers, it significantly reduces yellowing and color difference, enhances the UV anti-aging performance of the coating, and prolongs the durability and abrasion resistance of the pencil appearance.

[0023] 2. This solution will use a water-based, solvent-free resin system, select additives with low volatility, and decolorize and encapsulate the plant extracts to reduce VOC emissions. The combination of natural antioxidants and macaron colors provides good anti-mildew capabilities and is more suitable for personalized products with high environmental protection requirements. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the preparation process of the macaron-colored pencil paint of the present invention; Detailed Implementation

[0025] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise range thresholds, and these range thresholds should be understood to include values ​​close to these range thresholds. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0026] The present invention proposes an antioxidant formulation and preparation method for macaron-colored pencil paint, which mainly includes the following materials and specific implementation steps: An antioxidant formula for macaron-colored pencil paint, comprising the following components by weight: 30-40 parts water-based acrylic resin, 15-20 parts water-based polyurethane resin, 10-15 parts nano-grade diatomaceous earth, 1-3 parts natural plant extracts, 1-2 parts ultraviolet absorber, 0.5-1.5 parts antioxidant, 10-20 parts titanium dioxide, 0.1-2.0 parts water-based environmentally friendly color paste, 0.2-0.5 parts defoamer, 1-3 parts dispersant, 30-35 parts deionized water.

[0027] The natural plant extracts are one of the following: green tea extract, grape seed extract, rosemary extract, olive leaf extract, and tea tree essential oil extract. Their purity is between 80% and 95%, and all extracts have undergone decolorization treatment.

[0028] Water-based environmentally friendly color pastes include water-based red, water-based green, and water-based blue, which can be mixed with titanium dioxide to form macaron colors. The ultraviolet absorber used is one of the following: emulsion-type hydroxyphenyl triazine ultraviolet absorber, UV-1215, UV-400, and UV-5151; the antioxidant is one of the following: water-soluble vitamin E derivative, hydrogenated dibenzothiophene, and vanillin.

[0029] The water-based environmentally friendly pigments used include any one of water-based red, water-based green, and water-based blue pigments, mixed with rutile titanium dioxide in a ratio based on mass, i.e., the total amount of pigments. Light macaron colors are prepared using a ratio of magenta pigment to titanium dioxide of 0.01 to 0.03. Medium macaron colors are prepared using a ratio of ultramarine blue pigment to titanium dioxide of 0.03 to 0.06. Saturated macaron colors are prepared using a ratio of chrome green pigment to titanium dioxide of 0.06 to 0.12.

[0030] The pretreatment of nano-diatomaceous earth involves selecting untreated 200-300 mesh diatomaceous earth, washing it with deionized water until the diatomaceous earth is completely submerged, agitated to ensure thorough contact, filtering to remove impurities, and repeating the washing process 2-3 times. In the second wash, 0.1-0.5% dilute sulfuric acid is added to remove some acid-soluble heavy metal impurities. Finally, the diatomaceous earth is rinsed with deionized water until all sulfuric acid and impurities are removed. The washed diatomaceous earth is then sieved, selecting the 200-300 mesh fraction, and dried in an oven at 60-80℃ for 6-8 hours until the moisture content of the diatomaceous earth is below 5%.

[0031] Then select 0.6-1.0 mm zirconia beads as the grinding medium. Zirconia is hard and wear-resistant, which can effectively break up diatomaceous earth and avoid introducing impurities due to the breakage of the grinding medium. Grind the treated diatomaceous earth and deionized water at a mass ratio of 1:3 at room temperature for 4-6 hours. Use a particle size analyzer to ensure that the particle size of the ground diatomaceous earth reaches the range of 50-200 nm.

[0032] Finally, 0.5–2% of epoxy silane or methacryloxy silane provides amino functional groups as a surface modifier. 0.5–2% of epoxy silane or methacryloxy silane is ultrasonically dissolved in deionized water. The micronized diatomaceous earth is mixed with the surface modifier at a ratio of 1:2 and reacted at 100–300 rpm at room temperature for 2–4 hours to form an amino-functionalized layer on the surface of the diatomaceous earth.

[0033] Because natural plant extracts contain a large number of polyphenolic compounds, these components are easily degraded by light, turning yellow or brown, and easily oxidized by oxygen, causing color changes. Therefore, cyclodextrin is used to isolate oxygen and does not directly develop color, thus affecting the color performance of macarons. First, β-cyclodextrin is dissolved in deionized water at 40-50℃ using a mass ratio of β-cyclodextrin:natural plant extract = 1:0.5~2:1. The plant extract is pre-dissolved in a small amount of warm water. The system temperature is controlled at 30-40℃, and the extract solution is slowly added dropwise to the cyclodextrin solution. The mixture is stirred for 1-2 hours and adjusted to pH 5-6 for inclusion. Then, the temperature is lowered to 4-10℃ to promote inclusion, and the mixture is separated by centrifugation or filtration. Finally, spray drying is used to obtain the included powder.

[0034] The flowchart of the preparation process of the antioxidant formula for macaron-colored pencil paint is as follows: Figure 1 As shown, the specific implementation steps are as follows: S1: Disperse 60-80% deionized water, 0.2-0.5 parts defoamer, 10-15 parts pretreated nano-sized diatomaceous earth, 10-20 parts titanium dioxide, and 1-3 parts dispersant in a stirred tank at a high speed of 2000-3000 rpm for 15-20 minutes to obtain a white base slurry.

[0035] S2: Pour 30-40 parts of waterborne acrylic resin and 15-20 parts of waterborne polyurethane resin into the white base slurry of S1. Reduce the stirring speed to 1000-1200 rpm and disperse for 10-15 min. Add 0.1-2.0 parts of waterborne environmentally friendly color paste. Continuously add the remaining deionized water dropwise over 15-20 min. Continue dispersing at 25-35℃ for 30-40 min to obtain the base paint. Use a slow water addition method to form a polymer dispersion structure to avoid phase separation caused by adding too quickly.

[0036] Because the two resins have significantly different viscosities, the waterborne acrylic resin with lower viscosity is added first, followed by the waterborne polyurethane resin with higher viscosity, to avoid separation caused by adding them at the same time.

[0037] S3: Weigh 1-3 parts of natural plant extract and dissolve it in a solvent at a ratio of 1:5. Stir at 25-30℃ for 5-10 minutes to form a gel-like solution. Stir and add it to the base paint, controlling the temperature after addition at 25-30℃. Stir magnetically for 5-10 minutes. Add 1-2 parts of UV absorber and 0.5-1.5 parts of antioxidant. At the same time, reduce the speed to 300-600 rpm and stir for 8-12 minutes to remove bubbles under vacuum, reducing bubbles and preventing polyphenols from undergoing self-oxidation or discoloration due to excessive temperature. After standing for 24 hours without any layering, macaron-colored pencil paint is obtained.

[0038] Natural plant extracts mainly include green tea extract, grape seed extract, rosemary extract, olive leaf extract, and tea tree essential oil extract. Most of these have color, and the color of plant extracts can affect color performance. Therefore, cyclodextrin is used to reduce the color difference caused by natural plant extracts. The addition of natural plant extracts can reduce the volatilization of VOCs. During the addition process, an appropriate amount of light stabilizer HALS can be added to prevent and slow down photoinduced degradation.

[0039] Solvents for green tea extract and olive leaf extract: 3-8 parts deionized water, 2-6 parts propylene glycol, 0.05-0.2 parts AMP-95; Grape seed extract solvent: 3-7 parts propylene glycol, 2-5 parts propylene glycol methyl ether, 0.5-1.5 parts polysorbate-20; Rosemary extract solvent: 2-4 parts propylene glycol butyl ether, 4-7 parts propylene glycol, 1.5-3 parts polysorbate-80, and 0.5-1.5 parts deionized water; The solvent for tea tree essential oil extract consists of 2-4 parts propylene glycol butyl ether, 3-6 parts propylene glycol, 3-6 parts polysorbate-80, and 0.5-1.5 parts deionized water.

[0040] Example 1 An antioxidant formula for macaron-colored pencil paint, the main preparation process includes the following steps: S1: Disperse 60-80% deionized water, 0.2 parts defoamer, 10 parts pretreated nano-sized diatomaceous earth, 10 parts titanium dioxide, and 1 part dispersant in a stirred tank at 2000 rpm for 15 minutes to obtain a white base slurry.

[0041] S2: Pour 30 parts of water-based acrylic resin and 15 parts of water-based polyurethane resin into the white base slurry of S1, reduce the stirring speed to 1000 rpm, disperse for 10 min, add 0.1 parts of water-based environmentally friendly color paste, continuously add the remaining deionized water over 15 min, and continue to disperse at 25℃ for 30 min to obtain the base color paint. S3: Weigh 1 part of natural plant extract and dissolve it in solvent at a ratio of 1:5. Stir at 25°C for 5 minutes to form a gel-like solution. Stir and add it to the base paint, and control the temperature at 25°C after addition. Stir magnetically for 5 minutes. Add 1 part of UV-1215 and 0.5 parts of water-soluble vitamin E derivative. At the same time, reduce the speed to 300 rpm and stir for 8 minutes to remove bubbles under vacuum. Let it stand for 24 hours without any layering phenomenon to obtain macaron-colored pencil paint.

[0042] The titanium dioxide used in this scheme is rutile titanium dioxide, the natural plant extract is 85% pure decolorized grape seed extract, the solvent for dissolving the grape seed extract is composed of 55 parts propylene glycol, 25 parts propylene glycol methyl ether, and 7 parts polysorbate-20, and the dispersant is a 5% by mass aqueous solution of sodium polycarboxylate dispersant, wherein the content of sodium polycarboxylate dispersant accounts for 3.0% of the total solid weight.

[0043] Example 2 An antioxidant formula for macaron-colored pencil paint, the main preparation process includes the following steps: S1: Deionized water, 0.5 parts defoamer, 15 parts pretreated nano-sized diatomaceous earth, 20 parts titanium dioxide, and 3 parts dispersant are dispersed in a stirred tank at 3000 rpm for 20 minutes to obtain a white base slurry.

[0044] S2: Pour 40 parts of water-based acrylic resin and 20 parts of water-based polyurethane resin into the white base slurry of S1, reduce the stirring speed to 1200 rpm, disperse for 15 min, add 2.0 parts of water-based environmentally friendly color paste, continuously add the remaining deionized water over 20 min, and continue to disperse at 35℃ for 40 min to obtain the base color paint. S3: Weigh 3 parts of natural plant extract and dissolve them in a solvent at a ratio of 1:5. Stir at 30°C for 10 minutes to form a gel-like solution. Stir and add to the base paint, keeping the temperature at 30°C after addition. Stir magnetically for 10 minutes. Add 2 parts of UV-400 and 0.5 to 1.5 parts of hydrogenated dibenzothiophene. Simultaneously, reduce the speed to 600 rpm and stir for 12 minutes to remove bubbles under vacuum. Let stand for 24 hours without any layering to obtain macaron-colored pencil paint.

[0045] In this embodiment, the natural plant extract used is 85% green tea extract. The solvent for dissolving the green tea extract consists of 82 parts deionized water, 12 parts propylene glycol, and 0.3 parts AMP-95. The dispersant is a 10% sodium polycarboxylate dispersant aqueous solution, wherein the sodium polycarboxylate dispersant content accounts for 8.0% of the total solid weight.

[0046] Example 3 An antioxidant formula for macaron-colored pencil paint, the main preparation process includes the following steps: S1: Deionized water, 0.3 parts defoamer, 12 parts pretreated nano-sized diatomaceous earth, 15 parts titanium dioxide, and 2 parts dispersant are dispersed in a stirred tank at 2500 rpm for 17 minutes to obtain a white base slurry.

[0047] S2: Pour 35 parts of water-based acrylic resin and 17 parts of water-based polyurethane resin into the white base slurry of S1, reduce the stirring speed to 1100 rpm, disperse for 12 min, add 1.0 part of water-based environmentally friendly color paste, continuously add the remaining deionized water over 17 min, and continue to disperse at 30℃ for 35 min to obtain the base color paint. S3: Weigh 2 parts of natural plant extract and dissolve them in a solvent at a ratio of 1:5. Stir at 27°C for 7 minutes to form a gel-like solution. Stir and add to the base paint, and control the temperature at 27°C after addition. Stir magnetically for 7 minutes. Add 1 part of UV-5151 and 1.0 part of vanillin. At the same time, reduce the speed to 450 rpm and stir for 10 minutes to remove bubbles under vacuum. Let stand for 24 hours without any layering to obtain macaron-colored pencil paint.

[0048] The natural plant extract used in this embodiment is olive leaf extract. The solvent for dissolving the olive leaf extract consists of 82 parts deionized water, 12 parts propylene glycol, and 0.3 parts AMP-95. The dispersant is an aqueous solution of sodium polycarboxylate dispersant with a mass fraction of 12%, wherein the content of sodium polycarboxylate dispersant accounts for 6% of the total solid weight.

[0049] Example 4 An antioxidant formula for macaron-colored pencil paint, the main preparation process includes the following steps: S1: Deionized water, 0.3 parts defoamer, 11 parts pretreated nano-sized diatomaceous earth, 11 parts titanium dioxide, and 1 part dispersant are dispersed in a stirred tank at 2100 rpm for 16 minutes to obtain a white base slurry.

[0050] S2: Pour 31 parts of waterborne acrylic resin and 16 parts of waterborne polyurethane resin into the white base slurry of S1, reduce the stirring speed to 1050 rpm, disperse for 11 min, add 0.2 parts of waterborne environmentally friendly color paste, and continuously add the remaining deionized water over 16 min. Continue to disperse at 26℃ for 31 min to obtain the base paint. Since the viscosity of the two resins differs greatly, the waterborne acrylic resin with lower viscosity is added first, followed by the waterborne polyurethane resin with higher viscosity, to avoid separation caused by simultaneous addition.

[0051] S3: Weigh 1 part of natural plant extract and dissolve it in solvent at a ratio of 1:5. Stir at 26℃ for 6 minutes to form a gel-like solution. Stir and add it to the base paint, and control the temperature at 26℃ after addition. Stir magnetically for 6 minutes. Add 1 part of emulsion-type hydroxyphenyl triazine UV absorber and 0.6 parts of water-soluble vitamin E derivative. At the same time, reduce the speed to 350 rpm and stir for 9 minutes to remove bubbles under vacuum. Let it stand for 24 hours without any layering to obtain macaron-colored pencil paint.

[0052] In this embodiment, the natural plant extract used is 85% rosemary extract. The solvent for dissolving the rosemary extract consists of 25 parts propylene glycol butyl ether, 45 parts propylene glycol, 17 parts polysorbate-80, and 7 parts deionized water. The dispersant is an aqueous solution of sodium polycarboxylate dispersant with a mass fraction of 6%, wherein the content of sodium polycarboxylate dispersant accounts for 4.0% of the total solid weight.

[0053] Example 5 An antioxidant formula for macaron-colored pencil paint, the main preparation process includes the following steps: S1: Deionized water, 0.4 parts defoamer, 14 parts pretreated nano-sized diatomaceous earth, 19 parts titanium dioxide, and 3 parts dispersant are dispersed in a stirred tank at 2900 rpm for 19 minutes to obtain a white base slurry.

[0054] S2: Pour 39 parts of waterborne acrylic resin and 16 parts of waterborne polyurethane resin into the white base slurry of S1, reduce the stirring speed to 1150 rpm, disperse for 14 min, add 1.9 parts of waterborne environmentally friendly color paste, continuously add the remaining deionized water over 19 min, and continue to disperse at 34℃ for 39 min to obtain the base color paint. S3: Weigh 3 parts of natural plant extract and dissolve them in a solvent at a ratio of 1:5. Stir at 29°C for 9 minutes to form a gel-like solution. Stir and add the solution to the base paint, keeping the temperature at 29°C after addition. Stir magnetically for 9 minutes. Add 2 parts of UV-1215 and 1.4 parts of water-soluble vitamin E derivative. Simultaneously, reduce the speed to 550 rpm and stir for 11 minutes to remove bubbles under vacuum. Let stand for 24 hours without any layering to obtain macaron-colored pencil paint.

[0055] In this embodiment, the natural plant extract used is tea tree oil extract with a purity of 85%. The solvent for dissolving the tea tree oil extract consists of 25 parts propylene glycol butyl ether, 35 parts propylene glycol, 35 parts polysorbate-80, and 7 parts deionized water. The dispersant is an aqueous solution of sodium polycarboxylate dispersant with a mass fraction of 9%, wherein the content of sodium polycarboxylate dispersant accounts for 7.0% of the total solid weight.

[0056] Comparative Example 1 In step S3, the natural plant extract is not contained in cyclodextrin but is directly added to the paint system. The remaining steps are the same as in Example 1.

[0057] Comparative Example 2 No chemical modification was performed on the nano-diatomite in step S2, and the remaining steps were the same as in Example 1.

[0058] Comparative Example 3 No natural plant extracts are added in step S3, and the remaining steps are the same as in Example 1.

[0059] Comparative Example 4 Replace the rutile titanium dioxide used in step S1 with ordinary titanium dioxide, and follow the same steps as in Example 1.

[0060] The macaron-colored pencil paints prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to the following performance tests: 1. VOC Measurement Referring to GB / T23985-2009 "Determination of Volatile Organic Compounds (VOC) Content in Paints and Varnishes - Difference Method", a fixed amount of coating was taken, and the sample was heated to allow the volatiles to enter the GC for separation and detection of VOCs. VOC (g / L) = (mass of volatiles - mass of moisture) / volume of the cured coating film.

[0061] 2. Microbial preservative assay Referring to GB / T21872 Test for Anti-mold Properties of Coating Films, macaron paint was evenly applied to uncoated pine chips and dried and cured under specified conditions. Under aseptic conditions, a mixed suspension of mold spores was evenly sprayed onto the surface of the paint film on the sample. The inoculated sample was then placed in a mold test chamber with adjusted temperature and humidity and cultured for 28 days at a temperature of 28℃±1℃ and a relative humidity of 90%±2%.

[0062] 3. Aging test Referring to GB / T16422.3-2022 "Laboratory Light Source Exposure Test Methods for Plastics - Part 3: Fluorescent Ultraviolet Lamps", the prepared macaron paint was applied to an ABS plastic sheet and cured under standard conditions until completely dry, ensuring uniform paint film thickness and compliance with test requirements. A UVA-340 fluorescent ultraviolet lamp was selected, whose spectrum, within the wavelength range of 295nm to 365nm, highly matches the ultraviolet portion of sunlight. Continuous ultraviolet irradiation for 8 hours at 60℃±3℃ initiated photodegradation of the resin and fading of the pigments. At 50℃±3℃, without light exposure and with condensation occurring for 4 hours, thermal stress and moisture penetration accelerated coating aging, blistering, and loss of adhesion.

[0063] The performance test results of Examples 1-5 and Comparative Examples 1-4 are shown in Table 1: Table 1: Summary of Performance Results of Examples and Comparative Examples The VOC content in the example groups (45–49 g / L) was significantly lower than the average of 50.3 g / L in the comparative examples. In particular, the VOC content in the comparative example group (255 g / L) was 22% higher due to insufficient adsorption capacity caused by unmodified diatomaceous earth. Regarding anti-mold performance, all examples achieved a grade of 0–1, while the anti-mold grades in comparative examples 1–3 were reduced to grades 2–3 due to the lack of plant extract inclusion technology, unmodified diatomaceous earth, or omission of extracts. Comparative example 4 achieved a grade of 1 in anti-mold performance, confirming that the type of titanium dioxide does not affect anti-mold properties, highlighting the core role of plant extract cyclodextrin inclusion technology and chemical modification of diatomaceous earth in reducing VOCs and improving anti-mold performance.

[0064] In the UV aging test, the color difference ΔE in the example group was ≤1.9, almost imperceptible to the naked eye, with only slight loss of gloss. In contrast, the comparative group had ΔE ≥3.5, and generally exhibited chalking, mold growth, and fading. Specifically, Comparative Example 1 (ΔE 3.5) showed localized mold spots due to the degradation of active ingredients caused by the direct addition of extracts; Comparative Example 2 showed chalking and decreased adhesion due to the structural defects of unmodified diatomaceous earth; Comparative Example 3 (ΔE 5.0) showed severe mold growth and fading due to the complete omission of plant extracts; and Comparative Example 4 (ΔE 4.8) confirmed that ordinary titanium dioxide has poor weather resistance, leading to the exposure of the base color and chalking.

[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An antioxidant formula for macaron-colored pencil paint, characterized in that, The antioxidant formula for the macaron-colored pencil paint comprises the following components by weight: 30-40 parts water-based acrylic resin, 15-20 parts water-based polyurethane resin, 10-15 parts nano-grade diatomaceous earth, 1-3 parts natural plant extracts, 1-2 parts ultraviolet absorber, 0.5-1.5 parts antioxidant, 10-20 parts titanium dioxide, 0.1-2.0 parts water-based environmentally friendly color paste, 0.2-0.5 parts defoamer, 1-3 parts dispersant, 40-48 parts deionized water, and 5-15 parts natural plant extract solvent.

2. The antioxidant formula for macaron-colored pencil paint according to claim 1, characterized in that, The dispersant is a 5-10% aqueous solution of sodium polycarboxylate dispersant, wherein the sodium polycarboxylate dispersant content accounts for 3.0-8.0% of the total solid weight.

3. The antioxidant formulation for macaron-colored pencil paint according to claim 1, characterized in that, The nano-sized diatomaceous earth has a particle size of 50–200 nm and a specific surface area of ​​200–500 m². 2 / g and the surface is chemically modified with epoxy silane or methacryloxy silane.

4. The antioxidant formula for macaron-colored pencil paint according to claim 1, characterized in that, The natural plant extract is one of green tea extract, grape seed extract, rosemary extract, olive leaf extract, and tea tree essential oil extract, with a purity of 80% to 95%, and all extracts have undergone decolorization treatment.

5. The antioxidant formulation for macaron-colored pencil paint according to claim 1, characterized in that, The water-based environmentally friendly color paste is formed by mixing one or more of the following pigments—water-based red, water-based green, and water-based blue—with titanium dioxide to create a macaron color system.

6. The antioxidant formula for macaron-colored pencil paint according to claim 1, characterized in that, The ultraviolet absorber is one of the following: emulsion-type hydroxyphenyltriazine ultraviolet absorber, UV-1215, UV-400, and UV-5151.

7. The antioxidant formula for a macaron-colored pencil coating according to claim 1, characterized in that, The antioxidant is one of the following: a water-soluble vitamin E derivative, hydrogenated dibenzothiophene, or vanillin.

8. The antioxidant formulation for macaron-colored pencil paint according to claim 1, characterized in that, The solvents for the natural plant extracts include the following four types: a solvent composed of 3-8 parts deionized water, 2-6 parts propylene glycol, and 0.05-0.2 parts AMP-95 that can dissolve either green tea extract or olive leaf extract; a solvent composed of 3-7 parts propylene glycol, 2-5 parts propylene glycol methyl ether, and 0.5-1.5 parts polysorbate-20 that can dissolve grape seed extract; a solvent composed of 2-4 parts propylene glycol butyl ether, 4-7 parts propylene glycol, 1.5-3 parts polysorbate-80, and 0.5-1.5 parts deionized water that can dissolve rosemary extract; and a solvent composed of 2-4 parts propylene glycol butyl ether, 3-6 parts propylene glycol, 3-6 parts polysorbate-80, and 0.5-1.5 parts deionized water that can dissolve tea tree essential oil extract.

9. A method for preparing an antioxidant formulation for macaron-colored pencil paint according to any one of claims 1 to 8, characterized in that, Prepared by the following steps: S1: Mix and disperse 60-80% of the formula amount of deionized water, defoamer, pretreated nano-sized diatomaceous earth, titanium dioxide and dispersant at 2000-3000 rpm for 15-20 min to obtain a stable white base slurry. S2: Mix the water-based acrylic resin and water-based polyurethane resin in the formula amount and add them to the white base slurry of S1 to form a resin mixture. Reduce the stirring speed to 1000-1200 rpm and disperse for 10-15 min. Add water-based environmentally friendly color paste and the remaining deionized water. Continue to disperse at 25-35℃ for 30-40 min to obtain the base color paint. S3: Dissolve the natural plant extract in the formula with the solvent, add it to the base paint, and stir magnetically at 25-30℃ for 5-10 minutes. Add the UV absorber and antioxidant in the formula, mix and stir at 300-600 rpm for 8-12 minutes under vacuum to remove bubbles. Let it stand for 24 hours without any layering to obtain macaron-colored pencil paint.

10. The method for preparing the antioxidant formulation of macaron-colored pencil paint according to claim 9, characterized in that, The pretreatment step of nano-sized diatomaceous earth in step S1 is as follows: wash the untreated diatomaceous earth with deionized water 2 to 3 times, grind it with 0.6 to 1.0 mm zirconia beads at room temperature for 4 to 6 hours, add 0.5 to 2% epoxy silane or methacryloxy silane and react for 2 to 4 hours, then dry it for later use to obtain nano-sized diatomaceous earth.

Images