Single-component room-temperature-drying high-hardness chemical-resistant ultra-matte black coating for bathroom

Abstract

The invention discloses a single-component room-temperature-dried high-hardness chemical-resistant extra-matte black coating for bathroom accessories. The single-component room-temperature-dried high-hardness chemical-resistant extra-matte black coating is prepared from, by mass, 30%-45% of self-drying nano organic silicon resin, 5%-15% of low-acid-value acrylic resin, 5%-15% of low-molecular-weight modified epoxy resin, 5%-12% of resin-free black paste, 1%-2% of hydrophobic matting powder, 0.2%-0.3% of a flatting agent, 0.2%-0.3% of a defoaming agent, 0.1%-0.3% of a rheological additive and 25%-40% of a mixed organic solvent. The ultra-matte black coating is simple and convenient to construct, can be self-dried to form a film at normal temperature, does not need to be baked, and reduces energy consumption; the pencil hardness is greater than or equal to 4H, the hardness is high, and the scratch resistance is excellent; the performance of resisting acid, alkali, salt, alcohol, bleaching agents and coloring agents is comprehensive; the method is suitable for various substrates such as metal, ceramic, enamel and artificial stone.

Description

Technical Field

[0001] This invention belongs to the field of surface coating technology, specifically relating to a single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use, which is particularly suitable for the decoration and protection of substrates such as metal, ceramic, enamel, and artificial stone. Background Technology

[0002] To meet more personalized needs, many bathroom products now have surface coatings, serving both protective and decorative purposes, such as different colors. Matte black is particularly popular due to its understated and sophisticated aesthetic.

[0003] Bathroom products, during long-term use, are frequently exposed to acidic cleaners, alkaline detergents, bleach, alcohol disinfectants, pigment-containing cleaning solutions, and high-humidity and heat environments. Under these conditions, ordinary coatings may lose their gloss, discolor, blister, crack, or even peel off. Extra-matte (gloss level around 10) black paint, compared to other colors (such as white, transparent, pink, etc.), is more prone to loss of gloss and discoloration (whitening) in terms of chemical resistance.

[0004] Existing chemical-resistant black coatings are mostly two-component systems, requiring on-site mixing and curing, resulting in complex application procedures and short shelf lives. Some products require heating and baking for curing and drying, increasing energy consumption and application costs. While some single-component silicone-modified coatings possess certain chemical resistance, they often fail to meet the long-term resistance requirements of various chemical media. Therefore, it is crucial to develop a simple (single-component) black coating that can dry at room temperature, possesses high hardness (≥4H), and exhibits excellent chemical resistance (especially resistance to alcohols, acids, and alkalis). Summary of the Invention

[0005] The purpose of this invention is to provide a single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use. It is easy to apply, dries to form a film at room temperature, and has both high hardness (4H) and excellent chemical resistance. In particular, the coating can maintain a good appearance even under various chemical media such as acids, alkalis, salts, alcohols, bleaching agents, and colorants, thus meeting the dual needs of high-end decoration and protection in the bathroom industry.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: This invention discloses a single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use, comprising the following components by mass fraction: self-drying nano-organic silicone resin: 30%–45%, low-acid-value acrylic resin: 5%–15%, low-molecular-weight modified epoxy resin: 5%–15%, resin-free black paste: 5%–12%, hydrophobic matting agent: 1%–2%, leveling agent: 0.2%–0.3%, defoamer: 0.2%–0.3%, rheology modifier: 0.1%–0.3%, and mixed organic solvent: 25%–40%. The self-drying nano-organic silicone resin is a modified organosilicone resin with terminal methoxy groups (-OCH3) prepared by sol-gel method using epoxy-modified organosilane monomers and / or amino-modified organosilane monomers as raw materials. It has a particle size of 15-25 nm, a viscosity of 100-300 mPa·S at 25°C, and a solid content of 52%-58%. For example, Z4807 self-drying nano-organic silicone resin from Shanghai Shuaike Chemical Co., Ltd. The low-acid-value acrylic resin is a thermoplastic acrylate polymer with an acid value of 3-7 mgKOH / g, a glass transition temperature (Tg) of 80±5℃, a viscosity of 11000-16000 mPa·S at 25℃, and a solid content of 52%-58%; for example, RS2518-55 from Bogo Synthetic Materials. The low molecular weight modified epoxy resin is a xylene solution of a "Type 1" low molecular weight epoxy resin generated by the reaction of epichlorohydrin and bisphenol A, with an epoxy equivalent (g / eq) of 425–350, a viscosity of 11,000–16,000 mPa·s at 25°C, and a solid content of 72%–78%; for example, Dow Chemical's DER671-X75. The resin-free black paste is a highly dispersed carbon black paste without resin, with a particle size ≤0.5μm and a pigment content of 18% to 23%, such as Index Pigment's carbon black BK9008-UNR. The hydrophobic matting powder is a hydrophobic, high-porosity amorphous silica powder with an organic wax-treated surface. It has an average particle size of 4.6±1.2μm and an oil absorption value of approximately 200-500g / 100g; for example, Grace's SYLOID7000 matting powder. The defoamer is at least one of modified polysiloxane defoamer or modified polyether polymer solution, such as DEFOM 5300 from Hemings Dechian, BYK 141 and BYK 052N from BYK Chemicals; the leveling agent is a polyester modified polysiloxane solution, such as BYK 310 polyester modified polysiloxane solution from BYK Chemicals; the rheology modifier is a urea modified polyamide solution, such as BYK 430 polyester modified polysiloxane solution from BYK Chemicals. The mixed organic solvent is a mixture of propylene glycol methyl ether acetate (PMA) and butyl acetate in a mass ratio of 1:(0.9 to 1.2).

[0007] Compared with the prior art, the present invention has the following technical advantages: This invention utilizes self-drying nano-organic silicone resin to improve the hardness and some chemical resistance of the matte black coating, but its alcohol and alkali resistance are slightly inferior; low-acid-value acrylic resin can improve the alcohol resistance of the matte black coating, but its hardness is insufficient; low molecular weight modified epoxy resin can improve the adhesion of the coating, further enhancing chemical resistance, flexibility, and salt spray resistance, but its hardness is low. The optimized combination of the above three resins results in a single-component, room-temperature drying, high-hardness, chemical-resistant matte black coating for bathroom use. This single-component system has a storage stability of over 6 months, self-dries at 15–35°C without the need for additional curing agents or baking processes, and can be directly sprayed for easy application without on-site mixing; it self-dries at room temperature without baking, reducing energy consumption; it has a pencil hardness ≥4H, high hardness, and excellent scratch resistance; it exhibits comprehensive resistance to acids, alkalis, salts, alcohols, bleach, and colorants; and it is suitable for various substrates such as metals, ceramics, enamel, and artificial stone. Detailed Implementation

[0008] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0009] Examples 1-3 The mass fractions of the raw materials and components of the single-component, room-temperature-drying, high-hardness, chemical-resistant, matte black coatings for bathroom use in Examples 1-3 are listed in Table 1. The preparation method includes the following steps: (1) While the machine is stopped, add 15% of the total mass of mixed organic solvent (PMA to butyl acetate mass ratio 1:1) to the stirring container, then add self-drying nano silicone resin Z4807, low acid value acrylic resin RS2518-55 and low molecular weight modified epoxy resin DER671-X75 in sequence, and then stir at a speed of 500 rpm. (2) Add leveling agent BYK310, defoamer DEFOM 5300 and rheology modifier BYK430 under stirring; then stir and disperse at 1000 rpm for 50 min. (3) While stirring at 500 rpm, slowly add SYLOID 7000 hydrophobic matting powder, then disperse at 1600 rpm for 20 min, with a fineness ≤25 μm; (4) Add resin-free black paste BK9008-UNR under low speed (500 rpm) stirring, stir for 5 min, then add the remaining mixed organic solvent and stir well.

[0010] Among them, the self-drying nano-organic silicone resin is Z4807 self-drying nano-organic silicone resin from Shanghai Shuaike Chemical Co., Ltd.; the low acid value acrylic resin is RS2518-55 from Bogao Synthetic Materials Co., Ltd.; the low molecular weight modified epoxy resin is DER671-X75 from Dow Chemical Co., Ltd.; the resin-free black paste is carbon black BK9008-UNR from Yingdeco Pigment Co., Ltd.; the defoamer is BYK141 and BYK 052N from BYK Chemical Co., Ltd.; the leveling agent is BYK310 from BYK Chemical Co., Ltd.; the rheology modifier is BYK430 from BYK Chemical Co., Ltd.; and the hydrophobic matting powder is SYLOID 7000 matting powder.

[0011] Table 1. Mass fractions of raw materials and components in Examples 1-3 and Comparative Examples 1-2, in % Comparative Examples 1-6 Comparative Example 1 is a comparative example of Example 2, except that the self-drying nano-organic silicone resin in Comparative Example 1 is Z4806 polyurethane modified organic silicone resin from Shanghai Shuaike Chemical Co., Ltd.

[0012] Comparative Example 2 is a comparative example of Example 2, except that low-acid-value acrylic resin is not added in Comparative Example 2.

[0013] Comparative Example 3 is a comparative example of Example 2, except that no low molecular weight modified epoxy resin is added in Comparative Example 3.

[0014] Comparative Example 4 is a commercially available two-component polyurethane black coating, with matching isocyanate curing agent and thinner. After mixing and adjusting the viscosity according to the ratio, it is sprayed, dried at room temperature, and left to cure completely for 7 days before performance testing.

[0015] Comparative Example 5 is a commercially available high-temperature curing single-component polyester baking paint in black. After adding thinner to adjust the oil content, it was sprayed, baked at 170℃ for 30 minutes to cure into a film, and its performance was tested after 7 days.

[0016] Comparative Example 6 was a commercially available silicone-modified acrylic black coating. After adding a thinner to adjust the oil content, it was sprayed, allowed to air dry to form a film, and its performance was tested after 7 days.

[0017] Test Experiment Example The single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coatings for bathroom use from Examples 1-3 and Comparative Examples 1-6 were applied using the following method: filtration through a 100-mesh screen → manual spraying onto artificial stone → drying at 25°C for 24 hours. Performance tests were conducted 168 hours after spraying, and the results are shown in Table 2.

[0018] Table 2 Performance test results of Examples 1-3 and Comparative Examples 1-6 As can be seen from Table 2, the single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coatings for bathroom use prepared in Examples 1-3 of this invention exhibit excellent performance in multiple performance indicators: (1) Constructability: Examples 1-3 and Comparative Examples 1-3 are all single-component formulations that can self-dry and form a film in 24 hours at 15-35°C without the need for additional curing agents or diluents. Drying does not require heating; simply open the container, stir well, and it is ready for spraying. The application process is simple.

[0019] However, Comparative Example 1 only reached a hardness of 3H, and its resistance to alkalis and alcohols was slightly poor (loss of gloss, whitening). Comparative Example 2 had poor alcohol resistance, while Comparative Example 3 had poor resistance to acids, alkalis, salt spray, and impact. Comparative Example 4 (two-component polyurethane paint) required on-site mixing of the curing agent, resulting in a short usable time and a relatively cumbersome mixing process. Comparative Example 5 (one-component polyester baking paint) required high-temperature baking (170°C for 30 minutes), increasing construction and energy costs, and some workpieces were not suitable for high-temperature baking. Comparative Example 6 (one-component silicone-modified acrylic paint) was self-drying at room temperature, but its chemical resistance was significantly insufficient.

[0020] (2) Hardness and scratch resistance: The pencils in Examples 1-2 and Comparative Examples 2-3 have a hardness of 4H. However, Comparative Example 1 has poor alcohol resistance, and Comparative Example 2 has poor resistance to acids, alkalis, salt spray, and impact. The hardness of Comparative Example 1 only reaches 3H. The pencil in Example 3 has a hardness of 5H, which is significantly higher than that of Comparative Example 3 (H) and Comparative Examples 4-5 (2H). The higher hardness results in better scratch resistance.

[0021] (3) Chemical resistance In Examples 1-3, acid (10% acetic acid), alkali (10% NaOH), alcohol (70% ethanol), bleach (5% NaClO active Cl2), colorant (1% methylene blue), and salt (NaCl, 170 g / L, diluted to 50%) were dropped onto the paint film surface and left for 2 hours. After rinsing with water, the paint film showed no obvious loss of gloss, discoloration, or blistering, demonstrating excellent resistance to chemical media.

[0022] Comparative Example 1 showed slightly poorer resistance to alkalis and alcohols (loss of gloss, whitening). Comparative Example 2 showed poor alcohol resistance, while Comparative Example 3 showed poor resistance to acids, alkalis, and salt spray.

[0023] Comparative Example 4 showed whitening and loss of gloss in an acidic environment and in an alkaline environment. Comparative Example 6 showed whitening and loss of gloss in an acidic environment and in an ethanol environment.

[0024] (4) Salt spray resistance: Examples 1-3 showed no rust or blistering and the coating remained intact during a 500-hour neutral salt spray test.

[0025] Comparative Example 1 showed poor alcohol resistance, while Comparative Example 2 showed poor resistance to acids, alkalis, and salt spray.

[0026] Comparative Example 4 showed pitting and small bubbling during a 500-hour neutral salt spray test, while Comparative Example 6 showed slight rust.

[0027] In summary, Embodiments 1-3 of the present invention are significantly superior to commonly used two-component polyurethane paints, single-component polyester paints, and single-component silicone-modified acrylic paints in terms of ease of construction, room temperature self-drying, high hardness, multi-media resistance, and resistance to neutral salt spray. They are especially suitable for high-end decoration and protection of bathroom products and components made of metal, ceramics, enamel, artificial stone, etc.

Claims

1. A single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use, characterized in that: The product comprises the following components by mass fraction: self-drying nano-silicone resin: 30%–45%, low acid value acrylic resin: 5%–15%, low molecular weight modified epoxy resin: 5%–15%, resin-free black paste: 5%–12%, hydrophobic matting agent: 1%–2%, leveling agent: 0.2%–0.3%, defoamer: 0.2%–0.3%, rheology modifier: 0.1%–0.3%, and mixed organic solvents: 25%–40%.

2. The single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use according to claim 1, characterized in that, The self-drying nano-organic silicone resin is a methoxy-terminated (-OCH3) modified organic silicone resin prepared by sol-gel method using epoxy-modified organosilane monomers and / or amino-modified organosilane monomers as raw materials. It has a particle size of 15-25 nm, a viscosity of 100-300 mPa·S at 25°C, and a solid content of 52%-58%.

3. The single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use according to claim 1, characterized in that, The example of the self-drying nano-organic silicone resin is Z4807 self-drying nano-organic silicone resin from Shanghai Shuaike Chemical Co., Ltd.

4. The single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use according to claim 1, characterized in that, The low-acid-value acrylic resin is a thermoplastic acrylate polymer with an acid value of 3-7 mgKOH / g, a glass transition temperature (Tg) of 80±5℃, a viscosity of 11000-16000 mPa·S at 25℃, and a solid content of 52%-58%.

5. The single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use according to claim 1, characterized in that, The low molecular weight modified epoxy resin is a xylene solution of "Type 1" low molecular weight epoxy resin generated by the reaction of epichlorohydrin and bisphenol A, with an epoxy equivalent (g / eq) of 425-350, a viscosity of 11000-16000 mPa·S at 25°C, and a solid content of 72%-78%.

6. The single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use according to claim 1, characterized in that, The resin-free black paste is a highly dispersed carbon black paste without resin, with a particle size ≤0.5μm and a pigment content of 18% to 23%.

7. The single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use according to claim 1, characterized in that, The hydrophobic matting powder is a hydrophobic, high-porosity amorphous silica powder with an organic wax-treated surface. It has an average particle size of 4.6±1.2μm and an oil absorption value of approximately 200-500g / 100g.

8. The single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use according to claim 1, characterized in that, The defoamer is at least one of a modified polysiloxane defoamer or a modified polyether polymer solution; the leveling agent is a polyester-modified polysiloxane solution; and the rheology modifier is a urea-modified polyamide solution.

9. The single-component, room-temperature drying, high-hardness, chemical-resistant, matte black coating for bathroom use according to claim 1, characterized in that, The mixed organic solvent is a mixture of propylene glycol methyl ether acetate and butyl acetate in a mass ratio of 1:(0.9-1.2).

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