Anti-yellowing high-light-shining powder, preparation method and application thereof

Abstract

The present application relates to the technical field of high light flash powder, and particularly relates to an anti-yellowing high light flash powder, a preparation method and application thereof. The anti-yellowing high light flash powder is coated with a silver layer on the surface of a glass powder, and from inside to outside on the surface of the silver layer, a chemical anchoring layer, a surfactant layer and a protective film layer are sequentially coated; wherein the chemical anchoring layer, the surfactant layer and the protective film layer form a hierarchical structure to jointly constitute an anti-oxidation layer. The present application also discloses a preparation method of the anti-yellowing high light flash powder and application thereof in paint. The present application also discloses a paint, which comprises: a film-forming material and the anti-yellowing high light flash powder. The present application selects lipoic acid, silicone oil and a surfactant (lecithin and betaine) as the antioxidants, which cooperate with each other to form an anti-oxidation layer with a hierarchical structure, so that the anti-oxidation performance of the flash powder can be greatly improved, yellowing can be prevented, the high light flash powder can also maintain good dispersion stability and hydrophobicity, and good gloss and reflectivity can be maintained.

Description

Technical Field

[0001] This invention relates to the field of high-gloss glitter technology, and in particular to an anti-yellowing high-gloss glitter, its preparation method, and its application. Background Technology

[0002] With the increasing demands for decorative effects and material performance, high-gloss glitter has been widely used in coatings, plastics, cosmetics, printing, and other fields. Traditional high-gloss glitter mostly uses materials such as metal powder or ordinary glass powder, which has some limitations. Metal powder has poor oxidation resistance, easily discoloring and yellowing, affecting the durability of the decorative effect; ordinary glass powder has poor gloss and reflectivity, making it difficult to achieve the ideal high-gloss effect. Furthermore, the existing processing technology for high-gloss glitter is complex and costly, limiting its widespread application. Therefore, developing a new type of anti-yellowing high-gloss glitter material is of significant practical importance. Summary of the Invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes an anti-yellowing high-gloss glitter powder, its preparation method and application. The present invention selects thioctic acid, silicone oil and surfactants (lecithin and betaine) as antioxidants. They work together to form an antioxidant layer with a hierarchical structure, which can greatly improve the antioxidant performance of the glitter powder, prevent yellowing, and also maintain the high-gloss glitter powder with good dispersion stability and hydrophobicity, as well as maintain good gloss and reflectivity.

[0004] This invention proposes an anti-yellowing high-gloss glitter powder, which has a silver layer coated on the surface of glass powder, and a chemical anchoring layer, a surfactant layer, and a protective film layer coated on the surface of the silver layer from the inside out; wherein, the hierarchical structure formed by the chemical anchoring layer, the surfactant layer, and the protective film layer together constitutes an antioxidant layer.

[0005] Preferably, the chemical anchoring layer is a thioctic acid layer and the protective film layer is a silicone oil layer.

[0006] Preferably, the surfactant is lecithin and betaine.

[0007] Preferably, the glass powder is pretreated before being coated with a silver layer.

[0008] Preferably, the pretreatment step includes: washing the glass powder sequentially with a chelating agent solution, washing it with water, drying it, soaking it in an activator solution, washing it with water, and drying it.

[0009] Before washing with the chelating agent solution, the solution is first subjected to acid washing and alkali washing.

[0010] Acidic washing can be performed using hydrochloric acid solution, and alkaline washing can be performed using sodium hydroxide solution or potassium hydroxide solution. The order of acid washing and alkaline washing is not limited.

[0011] Preferably, the chelating agent is at least one of sodium gluconate and aminotrimethylenephosphonic acid.

[0012] Preferably, the concentration of the chelating agent solution is 0.01-0.7 g / ml, more preferably 0.01-0.07 g / ml.

[0013] Preferably, the solvent of the chelating agent solution is water.

[0014] This invention discovered that when using aminothiol chelating agents for washing, the silver layer after plating lacks sufficient density, is prone to peeling, and has low gloss. Through numerous experiments, this invention unexpectedly discovered that glass powder contains various metal ions (such as... , , , , , (etc.), while aminothiols mainly function by forming sulfur-metal bonds with metal ions, and only work with soft acid-type metal ions (such as... , , (etc.) have extremely strong chelating ability, but for common glass powders... , , , Hard acid ions have poor chelating ability and cannot be removed; this leads to problems such as low silver coverage, easy detachment of the silver layer, and low gloss after silver plating with glass powder. Furthermore, aminothiol chelating agents are generally stable in weakly acidic to neutral environments; however, they are easily oxidized and degraded (e.g., by disulfides) in strongly alkaline / strongly oxidizing environments, and may even produce odors or corrosion.

[0015] Therefore, through numerous experiments, this invention has found that sodium gluconate and aminotrimethylenephosphonic acid, when used as chelating agents, have a strong chelating ability with the aforementioned metal ions, and can effectively chelate and remove these metal ions at relatively low concentrations; furthermore, sodium gluconate and aminotrimethylenephosphonic acid have a wide pH range and good process compatibility.

[0016] This invention uses a specific chelating agent to wash the glass powder, which can chelate and remove metal ions from the surface of the glass powder, thereby improving the cleanliness of the glass powder. It can also improve the adhesion between the silver layer and the glass powder during silver plating, increase the coverage of the silver layer, avoid the problem of the silver layer easily falling off, which would lead to a decrease in gloss and reflectivity, and maintain the long-term stability of the high-gloss effect. The silver layer coverage has been tested to be as high as 99%.

[0017] Preferably, the solute in the activator solution is at least one of ferrous sulfate and sodium dithionite.

[0018] Preferably, the solute concentration of the activator solution is 0.001-0.0015 mol / L.

[0019] Preferably, the solvent of the activator solution is water.

[0020] Preferably, the sample is soaked in an activator solution for 1-3 hours.

[0021] Preferably, the thickness of the silver layer is 50-100 nm.

[0022] Preferably, the glass powder has a particle size of 50-150 μm.

[0023] The present invention also proposes a method for preparing the above-mentioned anti-yellowing high-gloss glitter powder, comprising the following steps: pretreating glass powder, then silver plating it to obtain silver-coated glass powder; mixing the silver-coated glass powder with an antioxidant solution, reacting, washing, and drying to obtain anti-yellowing high-gloss glitter powder.

[0024] Preferably, the antioxidants include: lipoic acid, silicone oil, and surfactants.

[0025] Preferably, the weight ratio of thioctic acid, silicone oil, and surfactant is 0.1-1:0.5-2:0.5-2.

[0026] The surfactants are lecithin and betaine; the weight ratio of lecithin to betaine can be 1:0.8-1.

[0027] Preferably, the amount of thioctic acid used is 0.1-1 wt% of the mass of the silver-coated glass powder.

[0028] Preferably, the solvent for the antioxidant solution is water.

[0029] Preferably, the concentration of lipoic acid in the antioxidant solution is 0.01-0.03 mol / L.

[0030] Preferably, the reaction is carried out at room temperature for 0.5-2 hours.

[0031] The above silver plating steps include: mixing the pretreated glass powder with a reducing agent solution, then adding a silver source solution to perform silver plating treatment, thereby obtaining silver-coated glass powder.

[0032] In the reducing agent solution, the concentration of the reducing agent is 20-50 g / L, and the solvent is water.

[0033] In the silver source solution, the concentration of silver ions is 10-30 g / L, and the solvent is water.

[0034] Silver plating is performed by adding silver source solution dropwise at 30-60℃ while stirring, for a total of 1-3 hours.

[0035] The reducing agent can be sodium ascorbate, etc., and the silver source can be silver nitrate, etc.

[0036] By selecting appropriate silver plating solutions and processes, this invention can control the silver deposition rate and the uniformity of the silver layer, and improve the adhesion of the silver layer.

[0037] The drying temperature is 50-80℃, and the drying time is 2-6 hours.

[0038] The present invention also proposes the application of the above-mentioned anti-yellowing high-gloss glitter powder in coatings.

[0039] The present invention also proposes a coating comprising: a film-forming substance and the above-mentioned anti-yellowing high-gloss glitter powder.

[0040] The film-forming substances mentioned above can be acrylic resin, epoxy resin, polyurethane, etc.

[0041] In the above coatings, the volume fraction of anti-yellowing high-gloss glitter can be 10-18 vol.

[0042] The aforementioned coatings may also include: antioxidants, dispersants, flame retardants, fillers, etc.

[0043] First, in the antioxidants described in this invention, lipoic acid preferentially anchors tightly to the surface of the silver layer through chemical adsorption (such as disulfide bonds, carboxyl groups, etc.), forming a dense basic hydrophobic layer, and causing the hydrophobic carbon chains to be distributed outward. Furthermore, lipoic acid can also scavenge free radicals on the surface of the silver layer, preventing oxidation reactions. Surfactants (lecithin and betaine) can be further adsorbed on the surface treated with lipoic acid, or fill the gaps in the basic hydrophobic layer of lipoic acid. The hydrophobic chains of lecithin and betaine can interact with the hydrophobic chains of lipoic acid through van der Waals forces, and the hydrophilic head groups of lecithin and betaine can form a specific structure facing the silver layer. Silicone oil can form a continuous physical coating film around the hydrophobic chains, which can encapsulate lipoic acid, lecithin, and betaine.

[0044] The aforementioned substances work synergistically to form a unique hierarchical structure, namely, a chemical anchoring layer (i.e., lipoic acid layer), a surfactant layer (i.e., lecithin and betaine), and a protective film layer (i.e., silicone oil layer) are sequentially coated on the surface of the silver layer from the inside out. This hierarchical structure forms a denser, more uniform, and more stable antioxidant layer, providing a stronger hydrophobic barrier that can better isolate water molecules and improve antioxidant performance.

[0045] Secondly, the hydrophobic chains of lecithin and betaine can work synergistically with the hydrophobic chains of lipoic acid to enhance the steric hindrance effect. In addition, the silicone oil layer also has strong steric hindrance. The three layers work together to improve the dispersion stability of the anti-yellowing high-gloss powder. Furthermore, the carboxyl groups of lipoic acid, the zwitterionic charge of betaine, and the phosphate ester / quaternary ammonium groups of lecithin can generate electrostatic repulsion in water or slightly polar systems to prevent agglomeration. Although the anchoring layer and surfactant layer are covered by the silicone oil layer, they can still generate a certain electrostatic effect when particles approach each other. The electrostatic effect is stronger, especially in water or slightly polar dispersion media, which can further improve the dispersion stability of the anti-yellowing high-gloss powder.

[0046] The aforementioned antioxidant layer, through the synergistic effect of multi-layered steric hindrance and electrostatic repulsion, significantly improves the dispersion stability of anti-yellowing high-gloss glitter and avoids agglomeration.

[0047] Third, the hydrophobic groups of lipoic acid, lecithin, betaine, and silicone oil in the above-mentioned antioxidant layer interact with each other, enhancing the stability of the entire antioxidant layer. The combination of lipoic acid, lecithin, betaine, and silicone oil can effectively transform the high-energy state of the silver layer surface into a low-energy hydrophobic state that matches the target non-polar medium (such as ink base material, organic solvent, etc.), achieving optimal wettability and compatibility, and improving the performance of anti-yellowing high-gloss glitter in the application of the target medium.

[0048] This invention selects thioctic acid, silicone oil, and surfactants (lecithin and betaine) as antioxidants. They work together to form an antioxidant layer with a hierarchical structure, which can significantly improve the antioxidant performance of high-gloss glitter, prevent yellowing, and maintain the high-gloss glitter's good dispersion stability and hydrophobicity, as well as good gloss and reflectivity. Attached Figure Description

[0049] Figure 1 This is a SEM image of the silver-coated glass powder prepared in Example 1.

[0050] Figure 2 This is a SEM image of the silver-coated glass powder prepared in Example 2.

[0051] Figure 3 The images show the coatings prepared with the anti-yellowing high-gloss glitter powder of Comparative Example 5 and Example 1 after the anti-oxidative yellowing test. The left side is Comparative Example 5, and the right side is Example 1. Detailed Implementation

[0052] The technical solution of the present invention will be described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0053] The water used in the following examples and comparative examples is deionized water.

[0054] Example 1

[0055] A method for preparing an anti-yellowing high-gloss glitter powder includes the following steps:

[0056] Take 100g of glass powder with a particle size of 50-150μm, wash it successively with 500mL of 0.1mol / L hydrochloric acid aqueous solution and 500mL of 0.1mol / L sodium hydroxide aqueous solution, then add it to 500mL of 0.07 g / mL sodium gluconate aqueous solution, stir and wash at 70℃ for 0.5h, then wash with water, dry at 100℃, then add it to 500mL of 0.001mol / L ferrous sulfate aqueous solution, soak at room temperature for 1h, wash with water, and dry at 100℃ to obtain pretreated glass powder;

[0057] 100g of pretreated glass powder was mixed with 3L of a 50 g / L ascorbic acid aqueous solution. Then, while stirring, 1.05L of a 30 g / L silver nitrate aqueous solution was added dropwise at 30℃ for silver plating. The silver plating process was carried out for 3 hours to obtain silver-coated glass powder with a silver layer thickness of 90nm. Its SEM image is shown below. Figure 1 As shown;

[0058] Mix 50g of silver-coated glass powder with an antioxidant aqueous solution, react at room temperature for 2 hours, wash, dry at 50℃ for 6 hours, and sieve to obtain anti-yellowing high-gloss glitter powder.

[0059] The antioxidants include: lipoic acid, silicone oil, and surfactants. In the aqueous solution of the antioxidants, the concentration of lipoic acid is 0.03 mol / L.

[0060] The weight ratio of thioctic acid, silicone oil, and surfactant is 0.5:1:1;

[0061] The surfactants are lecithin and betaine, with a weight ratio of 1:1.

[0062] The amount of thioctic acid used is 0.5 wt% of the mass of the silver-coated glass powder.

[0063] Example 2

[0064] A method for preparing an anti-yellowing high-gloss glitter powder includes the following steps:

[0065] Take 100g of glass powder with a particle size of 50-150μm, wash it successively with 500mL of 0.1mol / L hydrochloric acid aqueous solution and 500mL of 0.1mol / L sodium hydroxide aqueous solution, then add it to 500mL of 0.01 g / ml aminotrimethylenephosphonic acid aqueous solution, stir and wash at 50℃ for 0.5h, then wash with water, dry at 100℃, then add it to 500mL of 0.0015mol / L sodium dithionite aqueous solution, soak at room temperature for 3h, wash with water, and dry at 100℃ to obtain pretreated glass powder;

[0066] 100g of pretreated glass powder was mixed with 3L of a 20 g / L ascorbic acid aqueous solution. Then, 1745mL of a 10 g / L silver nitrate aqueous solution was added dropwise at 60℃ while stirring to perform silver plating. The addition was carried out for 1 hour to obtain silver-coated glass powder with a silver layer thickness of 50nm. The SEM image is shown below. Figure 2 As shown;

[0067] Mix 50g of silver-coated glass powder with an antioxidant aqueous solution, react at room temperature for 0.5h, wash, dry at 80℃ for 2h, and sieve to obtain anti-yellowing high-gloss glitter powder;

[0068] The antioxidants include: lipoic acid, silicone oil, and surfactants. In the aqueous solution of the antioxidants, the concentration of lipoic acid is 0.01 mol / L.

[0069] The weight ratio of thioctic acid, silicone oil, and surfactant is 0.1:0.5:0.5;

[0070] The surfactants are lecithin and betaine, with a weight ratio of lecithin to betaine of 1:0.8.

[0071] The amount of thioctic acid used is 0.1 wt% of the mass of the silver-coated glass powder.

[0072] Example 3

[0073] A method for preparing an anti-yellowing high-gloss glitter powder includes the following steps:

[0074] Take 100g of glass powder with a particle size of 50-150μm, wash it successively with 500mL of 0.1mol / L sodium hydroxide aqueous solution and 500mL of 0.1mol / L hydrochloric acid aqueous solution, then add it to 500mL of 0.07 g / mL sodium gluconate aqueous solution, stir and wash at 70℃ for 0.5h, then wash with water, dry at 100℃, then add it to 500mL of 0.0012mol / L ferrous sulfate aqueous solution, soak at room temperature for 2h, wash with water, and dry at 100℃ to obtain pretreated glass powder;

[0075] 100g of pretreated glass powder was mixed with 3L of 30 g / L ascorbic acid aqueous solution. Then, 1400mL of 20 g / L silver nitrate aqueous solution was added dropwise at 45℃ while stirring to perform silver plating treatment. The addition was carried out for 2 hours to obtain silver-coated glass powder with a silver layer thickness of 80nm.

[0076] Mix 50g of silver-coated glass powder with an antioxidant aqueous solution, react at room temperature for 1 hour, wash, dry at 60℃ for 4 hours, and sieve to obtain anti-yellowing high-gloss glitter powder.

[0077] The antioxidants include: lipoic acid, silicone oil, and surfactants. In the aqueous solution of the antioxidants, the concentration of lipoic acid is 0.02 mol / L.

[0078] The weight ratio of thioctic acid, silicone oil, and surfactant is 1:1:2;

[0079] The surfactants are lecithin and betaine, with a weight ratio of 1:1.

[0080] The amount of thioctic acid used is 1 wt% of the mass of the silver-coated glass powder.

[0081] Comparative Example 1

[0082] Replace "sodium gluconate" with "cysteamine" and prepare anti-yellowing high-gloss glitter powder according to the method of Example 1.

[0083] Comparative Example 2

[0084] Replace "aminotrimethylenephosphonic acid" with "acetylcysteine" and prepare anti-yellowing high-gloss glitter powder according to the method of Example 2.

[0085] Comparative Example 3

[0086] The antioxidant does not contain surfactants, and the other anti-yellowing high-gloss glitter powders are prepared according to the method in Example 1.

[0087] Comparative Example 4

[0088] The antioxidant does not contain silicone oil, and the other anti-yellowing high-gloss glitter powders are prepared according to the method in Example 1.

[0089] Comparative Example 5

[0090] The antioxidant does not contain lipoic acid, and the other anti-yellowing high-gloss glitter powders are prepared according to the method in Example 1.

[0091] Comparative Example 6

[0092] Replace “lipoic acid” with “acetylcysteine”, and prepare the anti-yellowing high-gloss glitter powder according to the method in Example 1.

[0093] The anti-yellowing high-gloss powders obtained in Examples 1-3 and Comparative Examples 1-6 were used to prepare paints in the same amounts (paint formulation: Phase A: 65wt% thermosetting acrylic resin ethyl acetate solution with a solid content of 50wt%, 0.5wt% dispersant (BYK-163), 0.2wt% leveling agent (BYK-306), 14.8wt% mixed solvent (ethyl acetate: xylene = 1:1 v / v); Phase B: 15wt% anti-yellowing high-gloss powder, 3.5wt% talc, 1wt% spherical porous silica, 1wt% nylon-12 powder, 1wt% zinc stearate, 0.25wt% titanium dioxide (CI77891)). Coatings were prepared by scraping.

[0094] The coating's resistance to oxidative yellowing, hydrophobicity, L-value, a-value, and b-value were tested, and the uniform dispersion of each group of anti-yellowing high-gloss glitter powder in the paint was also examined. The results are shown in Table 1 and... Figure 3 As shown.

[0095] Figure 3 The images show the coatings prepared with the anti-yellowing high-gloss glitter powder of Comparative Example 5 and Example 1 after the anti-oxidative yellowing test. The left side is Comparative Example 5, and the right side is Example 1.

[0096] The detection methods for L-value, a-value, and b-value are as follows: Use a colorimeter to measure the L-value, a-value, and b-value of the paint film under the conditions of D65 light source / 10° observer. Measure 3-5 times at different positions on the paint film surface and take the average value.

[0097] Antioxidant yellowing test method: Place the coating in a QUV ultraviolet aging test chamber and test for 200 hours under the cycle conditions of UVA-340 lamp, irradiation at 60℃ / 8h + condensation at 50℃ / 4h. Then observe the paint film for yellowing with the naked eye.

[0098] Hydrophobicity testing method: Using a contact angle meter, drop a drop of ultrapure water (approximately 2 μL) onto the paint film surface and measure the static water contact angle. A contact angle >90° is considered hydrophobic.

[0099] Dispersion testing method: Observe under an optical microscope. Slightly dilute a drop of paint with an appropriate solvent (such as the mixed solvent in the formula) to prevent the paint film from being too thick to observe. Take a drop of diluted paint with a dropper and drop it onto a glass slide. Gently cover it with a coverslip to avoid air bubbles. Observe under a microscope in multiple fields of view whether the anti-yellowing high-gloss glitter is evenly dispersed. Dispersion directly determines the optical performance and appearance of the coating. The specular reflection effect of high-gloss glitter depends on its uniform and flat arrangement on the paint film surface. Once it agglomerates, it will become tiny bumps and depressions, turning specular reflection into diffuse reflection, resulting in decreased gloss, weakened glitter effect, or becoming mottled and uneven.

[0100]

[0101] From Table 1 and Figure 3 It can be seen that by selecting appropriate antioxidants and combining them with suitable processes, the present invention can make the glitter have a high gloss effect. Its L value, a value, and b value are all much better than those of comparative examples 1-6. After the antioxidant yellowing test, comparative example 5 showed obvious yellowing, while example 1 did not yellow and still maintained a high gloss state. The glitter described in the present invention has good antioxidant yellowing performance, hydrophobicity, and dispersibility.

[0102] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An anti-yellowing high-gloss glitter, characterized in that, The silver layer is coated on the surface of the glass powder, and from inside to outside, a chemical anchoring layer, a surfactant layer and a protective film layer are coated on the surface of the silver layer in sequence; wherein the chemical anchoring layer, the surfactant layer and the protective film layer form a hierarchical structure together to constitute an oxidation-resistant layer. The chemical anchoring layer is a lipoic acid layer, and the protective film layer is a silicone oil layer. The glass powder is coated with a silver layer after pretreatment. The pretreatment step comprises: sequentially washing the glass powder with a chelating agent solution and water, drying, immersing the glass powder in an activating agent solution, washing with water and drying. The chelating agent is at least one of sodium gluconate and amino-trimethylene phosphonic acid.

2. The anti-yellowing high-gloss sparkle powder of claim 1, wherein, The thickness of the silver layer is 50-100 nm.

3. A process for the preparation of the anti-yellowing high-gloss glitter according to claim 1 or 2, characterized in that, The method comprises the following steps: pretreating the glass powder, then carrying out silver plating treatment to obtain silver-coated glass powder; mixing the silver-coated glass powder with an anti-oxidant solution, carrying out reaction, washing and drying to obtain anti-yellowing high-light flash powder.

4. The preparation method of the anti-yellowing high-gloss glitter powder according to claim 3, characterized in that, The anti-oxidant comprises: lipoic acid, silicone oil and surfactant.

5. Application of the anti-yellowing high-light flash powder according to claim 1 or 2 in paint.

6. A coating material, characterized by It comprises: a film-forming material and the anti-yellowing high-light flash powder according to claim 1 or 2.

Images