Stain-resistant and scratch-resistant coating and preparation method thereof

Abstract

The invention relates to the technical field of coatings, and discloses a stain-resistant and scratch-resistant coating and a preparation method thereof. The stain-resistant and scratch-resistant coating is prepared from the following components in parts by weight: 0.3 to 0.8 part of cellulose, 0.2 to 1.0 part of chitosan, 22 to 26 parts of titanium dioxide, 0.5 to 3 parts of kaolin, 10 to 15 parts of precipitated barium sulfate, 0.05 to 0.3 part of LS bentonite, 0.5 to 1.5 parts of nano aluminum oxide, 30 to 38 parts of styrene-acrylic emulsion, 6 parts of covering emulsion, 0.2 to 1.0 part of scratch-resistant aid, 5.0 to 8.0 parts of aid and 15 to 20 parts of water. The coating disclosed by the invention has excellent stain resistance and scratch resistance, has very good storage stability, and is odorless and environment-friendly; the raw materials are convenient to purchase and prepare, and the cost advantage is achieved; the preparation method is simple, is suitable for large-scale production and popularization in an existing coating factory, is suitable for various construction modes, and has a wide market prospect.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and in particular to a stain-resistant and scratch-resistant coating and a preparation method thereof. Background Art

[0002] Existing stain-resistant and scratch-resistant technology products are mostly used in the fields of furniture, automobiles, electronic products, etc., and the product technology mostly uses two-component coatings, polyurethane coatings, epoxy coatings, UV curing coatings, graphene coatings, etc., which have high manufacturing costs and are relatively environmentally unfriendly. For example, the invention patent "Stain-resistant coating composition" with the publication number CN112424246B discloses a coating composition, which is prepared by (i) urethane acrylate resin particles; (ii) an aqueous dispersion of a mixture of acrylic resin particles; and (iii) a matting agent, a method for imparting stain resistance to a substrate; the invention patent "A high-hardness stain-resistant coating and its preparation method and application" with the publication number CN118620523A discloses an organic-inorganic hybrid binder synthesized by epoxy resin, silicone resin, tetraethoxysilane, silane coupling agent, tetrabutylphthalate or tetraisopropyl titanate, etc., which can be applied to any inorganic and plastic materials, and the coating film has high hardness (hardness can reach 5H), high gloss, stain resistance, and moderate toughness and softness.

[0003] Most of the functional coatings for interior walls have only single properties of stain resistance and scratch resistance, and the stain resistance function is mostly achieved through fluorocarbon resins, silicone coatings, nano coatings, etc. First, the raw materials used are expensive, and second, the silicone and nanoparticles used are all hydrophobic. For example, the invention patent with publication number CN119331477A "Anti-sewage coating, preparation method and application" discloses that a certain amount of silicon carbide powder and nano silicon dioxide are added to the compound of water-based fluorocarbon emulsion resin and water-based acrylic polyurethane resin to produce a synergistic effect of improving the adhesion of water-based coatings. Scratch-resistant coatings are mostly achieved through artistic paints containing sand or hollow glass beads. For example, the invention patent with publication number CN119101393A, "A scratch-resistant agent, a coating composition, and its preparation method and application", discloses that the scratch-resistant agent is added with sand powder, and is used in combination with high molecular weight and low molecular weight polydimethylsiloxane. When used in the coating composition, it can synergistically enhance the scratch resistance of the formed paint film in multiple dimensions while ensuring the paint film effect, especially for velvet artistic paint, without affecting the pearlescent effect of the paint film.

[0004] Therefore, there is an urgent need for a stain-resistant and scratch-resistant coating and a preparation method thereof to solve the above-mentioned technical problems. Summary of the invention

[0005] The present invention aims to overcome the existing technical problems and provide a stain-resistant and scratch-resistant coating and a preparation method thereof.

[0006] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0007] A stain-resistant and scratch-resistant coating comprises the following components in parts by weight:

[0008] 0.3-0.8 parts of cellulose, 0.2-1.0 parts of chitosan, 22-26 parts of titanium dioxide, 0.5-3 parts of kaolin, 10-15 parts of precipitated barium sulfate, 0.05-0.3 parts of LS bentonite, 0.5-1.5 parts of nano-alumina, 30-38 parts of styrene-acrylic emulsion, 6 parts of covering emulsion, 0.2-1.0 parts of anti-scratch additive, 5.0-8.0 parts of additives, 15-20 parts of water;

[0009] The auxiliary agents include dispersants, wetting agents, pre-defoaming agents, pH regulators, film-forming aids, post-defoaming agents, antifreeze agents, bactericidal preservatives, and thickeners.

[0010] Preferably, the cellulose is hydrophobically modified hydroxyethyl cellulose.

[0011] More preferably, the hydrophobically modified hydroxyethyl cellulose is a hydrophobically modified associative cellulose polymer, the backbone of which is connected with hydroxyethyl and alkyl groups, and the viscosity is 150 to 500 cp. TM Plus 330HMHEC.

[0012] Preferably, the relative molecular weight of the chitosan is 10,000 to 30,000; and the particle size of the nano-alumina is 20 to 60 nm.

[0013] Preferably, the precipitated barium sulfate is a mixture of modified precipitated barium sulfate and modified nano-precipitated barium sulfate, wherein the mass ratio of the modified precipitated barium sulfate to the modified nano-precipitated barium sulfate is (1-3):1; the particle size of the modified precipitated barium sulfate is 1250 mesh, and the particle size of the modified nano-precipitated barium sulfate is 30-400 nm.

[0014] Specifically, the 1250-mesh modified precipitated barium sulfate can be the modified precipitated barium sulfate from Shaanxi Fuhua.

[0015] Preferably, the preparation method of the modified nano-precipitated barium sulfate is as follows: micron-scale precipitated barium sulfate is configured into a slurry with a solid content of 40-60wt%, and the precipitated barium sulfate slurry of nanometer level is obtained by grinding; the precipitated barium sulfate slurry is added into a reaction kettle, and a modified coating agent of 1-3wt% of the mass of the precipitated barium sulfate and a starch modifier of 4-8wt% of the mass of the precipitated barium sulfate are added, and then homogenized, and then filtered, washed, dried and crushed to obtain modified nano-precipitated barium sulfate powder; wherein the modified coating agent is a nano-silicon dioxide slurry with a concentration of 100g / L, and the starch modifier is sodium dodecylbenzene sulfonate.

[0016] Specifically, the preparation method of modified nano-precipitated barium sulfate is as follows:

[0017] The precipitated barium sulfate with a solid content of 1250 mesh is prepared into a slurry with a solid content of 40-60wt%, and the precipitated barium sulfate slurry with a nanometer level is obtained through grinding; the precipitated barium sulfate slurry is added into a reaction kettle, the temperature is kept at 50-95°C, and a modified coating agent with a mass percentage of 1-3wt% of the precipitated barium sulfate and a starch modifier with a mass percentage of 4-8wt% of the precipitated barium sulfate are added; the modified coating agent and the starch modifier are added dropwise at a uniform speed within 40-60min to obtain a reaction solution; the pH value of the reaction solution is adjusted to be within the range of 6.5-8.5, and the reaction solution is homogenized for 40-60min; and then the reaction solution is filtered, washed, dried and crushed to obtain a modified nano-precipitated barium sulfate powder; wherein the modified coating agent is a nano-silicon dioxide slurry with a concentration of 100g / L, and the starch modifier is sodium dodecylbenzene sulfonate.

[0018] Specifically, the nano-silicon dioxide slurry uses nano-silicon dioxide with a particle size of 30 to 60 nm.

[0019] Specifically, 1250 mesh modified precipitated barium sulfate comes from Shaanxi Fuhua Chemical Co., Ltd.

[0020] Preferably, the titanium dioxide, kaolin and precipitated barium sulfate are all pigments and fillers; the pigments and fillers account for 35-40% of the weight of the stain-resistant and scratch-resistant coating; the mass ratio of the precipitated barium sulfate to the pigments and fillers is (0.2-0.4):1.

[0021] Preferably, the styrene acrylic emulsion is a high TG (glass transition temperature) emulsion, the TG range is 40-42° C., and the mass ratio of the styrene acrylic emulsion to the pigment and filler is (0.75-1.0):1.

[0022] Preferably, the anti-scratch agent is a silicone aqueous dispersion with an ultra-high molecular weight, the molecular weight of which is greater than 1 million.

[0023] More preferably, the silicone aqueous dispersion with ultra-high molecular weight is at least one of adhesion promoters containing silane coupling agent components such as polydimethylsiloxane, vinyl trimethoxysilane, vinyl triethoxysilane, etc. Specifically, any one of LAS255, Dow Corning 5-7299 silicone dispersion, EL-2551, YF-664 silicone dispersion, etc. can be used.

[0024] Preferably, the dispersant is ammonium polyacrylate; the auxiliary agent includes the following components in parts by weight: 0.6-0.9 parts of ammonium polyacrylate dispersant, 0.1-0.3 parts of wetting agent, 0.2-0.3 parts of pre-defoaming agent, 0.2-0.4 parts of pH regulator, 1-3 parts of film-forming auxiliary agent, 0.2-0.5 parts of post-defoaming agent, 0.8-1.5 parts of antifreeze agent, 0.3-0.5 parts of bactericidal preservative, and 0.2-0.5 parts of thickener.

[0025] Further preferably, the thickener can be selected from one, two, or more types, one of which is an alkali-swellable anionic thickener, which is a cross-linked polymer emulsion thickener formed by copolymerization of ethyl acrylate and methacrylic acid.

[0026] Specifically, the thickener can be at least one of Dow TT615, Dow TT935, Dow ASE60, Shanghai Caiyang 305, Aorun Chemical TA260, and Dow Chemical RM-8W.

[0027] In the present invention, the pre-defoaming agent is used to suppress the generation of mechanical bubbles; the post-defoaming agent is used to eliminate microbubbles. Those skilled in the art can select specific types according to actual use requirements. The present invention also includes a method for preparing a stain-resistant and scratch-resistant coating, comprising the following steps:

[0028] (1) adding water to a stirring device, and sequentially adding cellulose and chitosan while stirring; after the cellulose and chitosan are dissolved, adding a wetting agent, a dispersant, a pre-defoaming agent, and a film-forming aid, and stirring;

[0029] (2) adding titanium dioxide, kaolin, precipitated barium sulfate, nano-alumina, LS bentonite and pH adjuster and stirring, then adding styrene acrylic emulsion, covering emulsion, anti-scratch additive, post-defoaming agent, antifreeze agent, bactericidal preservative, thickener, stirring evenly to obtain a finished product of anti-fouling and anti-scratch coating.

[0030] Specifically, the following steps are included:

[0031] (1) adding water to a stirring device, adding cellulose and chitosan in sequence while stirring, adding a wetting agent, a dispersant, a pre-defoaming agent, and a film-forming aid after the cellulose and chitosan are dissolved, stirring evenly and switching to high-speed stirring;

[0032] (2) Add titanium dioxide, kaolin, precipitated barium sulfate, nano alumina, LS bentonite and pH adjuster, stir at high speed until dispersed evenly, then adjust to low speed, dispersibility ≤ 50 μm, add styrene acrylic emulsion, covering emulsion, anti-scratch additive, post-defoaming agent, antifreeze agent, bactericidal preservative, thickener, stir evenly to obtain a stain-resistant and scratch-resistant coating product.

[0033] Working principle:

[0034] (1) The physical adsorption and chemical bonding between chitosan and modified nano-precipitated barium sulfate and nano-alumina form a fine, uniform and hard network structure, which can significantly improve the wear resistance and scratch resistance of the coating. At the same time, the high surface activity and particle adsorption capacity of nano-alumina and modified nano-precipitated barium sulfate can greatly improve the adhesion and leveling properties of the coating, and significantly improve the stain resistance of the coating. The charge interaction between chitosan and modified nano-precipitated barium sulfate and nano-alumina also effectively improves the dispersion stability of nano-oxides in the coating.

[0035] (2) Precipitated barium sulfate with high Mohs hardness is used as filler to improve the hardness of the paint film and make it have good anti-scratch performance, and the precipitated barium sulfate accounts for 30-40% of the overall pigment filler; LS bentonite is used in combination to play a suspending and anti-settling role; if the amount of precipitated barium sulfate is too low, the anti-scratch performance will be affected, and if the amount is too high, the gloss and storage stability will be affected. The present invention selects a suitable amount, so that it has good anti-scratch performance while not affecting the gloss and storage stability.

[0036] (3) The present invention selects a suitable styrene acrylic emulsion and applies a high TG styrene acrylic emulsion with high hardness and good anti-sticking effect. The content of the styrene acrylic emulsion should be greater than 30%, accounting for 30% to 38% of the mass of the stain-resistant and scratch-resistant coating, and the appropriate ratio of the styrene acrylic emulsion to the pigment and filler is (0.75 to 1.0): 1, which further improves the stain resistance and scratch resistance of the product.

[0037] (4) The dispersant used is polyacrylate ammonium salt dispersant, which can improve the water resistance of the paint film and further improve the stain resistance and scratch resistance of the coating.

[0038] (5) Use alkali-swellable anionic thickener, which has plastic function and can create patterns and texture effects, so that it can be used in various construction methods and with different effect requirements.

[0039] (6) Add anti-scratch additives to improve the film-forming effect. The organic and inorganic functional groups contained in the anti-scratch additives react with styrene acrylic emulsion, thickener and filler, especially nano-alumina and modified nano-precipitated barium sulfate to further form a dense network silicon film, improve the adhesion to the substrate, etc., which can further improve the anti-scratch effect of the coating.

[0040] (7) The modified nano-precipitated barium sulfate prepared by the method of the present invention has a network-like multi-mesoporous structure and a high specific surface area on its surface due to nano-silicon dioxide, and is modified by a starch modifier to have good dispersion stability due to steric hindrance and surface charge; therefore, it has good adhesion when used in the coating system of the present invention, and can significantly improve the stain resistance and scratch resistance of the coating.

[0041] The formula design and raw material selection of the coating of the present invention are based on creative research, and the synergy between the raw materials is comprehensively utilized. In combination with sufficient experimental data and use effect support, it is proved that the coating of the present invention has excellent stain resistance and scratch resistance. The number of wash resistance of the coating of the present invention reaches more than 60,000 times, the stain resistance level reaches level 1, the hardness reaches more than 2H, and it has very good storage stability, and is odorless and environmentally friendly.

[0042] Beneficial effects:

[0043] The coating of the present invention has excellent stain resistance and scratch resistance. The number of times the coating of the present invention can be washed reaches more than 60,000 times, the stain resistance level reaches level 1, the hardness reaches more than 2H, and it has very good storage stability, is odorless and environmentally friendly; it is a cost-effective and environmentally friendly stain-resistant and scratch-resistant functional interior wall coating; the raw materials used in the coating of the present invention are easy to purchase and prepare, and have cost advantages; the preparation method of the present invention is simple, suitable for large-scale production and promotion in existing coating factories, suitable for various construction methods, and has broad market prospects. DETAILED DESCRIPTION

[0044] The present invention is further described below with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0045] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0046] There is no particular limitation on the purity of all raw materials in the present invention, and the present invention preferably adopts the conventional purity used in the art.

[0047] The devices used in the present invention are not particularly limited and can be any of the commonly used devices in the art.

[0048] The sources of some of the chemical materials used in the following embodiments and comparative examples are shown in the following table:

[0049]

[0050] The particle size of the nano-alumina used in the following examples and comparative examples is 20 to 60 nm.

[0051] The preparation method of the modified nano-precipitated barium sulfate used in Examples 1 to 3, Comparative Example 1, Comparative Example 4, and Comparative Example 5 is as follows:

[0052] The 1250 mesh precipitated barium sulfate is configured into a slurry with a solid content of 50wt%, and the precipitated barium sulfate slurry of nanometer level is obtained by grinding; the precipitated barium sulfate slurry is added into a reaction kettle, the temperature is kept at 75°C, and a modified coating agent of 2.5wt% based on the mass fraction of the precipitated barium sulfate and a starch modifier of 5wt% based on the mass fraction of the precipitated barium sulfate are added; the modified coating agent and the starch modifier are uniformly added dropwise within 40 to 60 minutes to obtain a reaction solution, the pH of the reaction solution is adjusted to be controlled within the range of 7.0, and homogenized for 60 minutes; then filtered, washed, dried and crushed to obtain a modified nano precipitated barium sulfate powder; wherein the modified coating agent is a nano silicon dioxide slurry with a concentration of 100g / L (concentration of 100g / L based on silicon dioxide), and the starch modifier is sodium dodecylbenzene sulfonate. The nano silicon dioxide slurry uses nano silicon oxide with a particle size of 30 to 60nm.

[0053] Example 1

[0054] A method for preparing a stain-resistant and scratch-resistant coating comprises the following steps:

[0055] Add 16.5 parts of water to a clean dispersion tank, place it in a stirring device, add 0.3 parts of hydrophobically modified hydroxyethyl cellulose and 0.5 parts of chitosan in sequence while stirring, add 0.3 parts of pre-defoaming agent, 0.20 parts of wetting agent, 0.8 parts of polyacrylate ammonium salt dispersant, 2.0 parts of odorless film-forming agent (film-forming aid) after dissolution, increase the speed after stirring evenly, add 24 parts of titanium dioxide, 1.0 parts of kaolin, 9.0 parts of modified precipitated barium sulfate, 4.5 parts of modified nano-precipitated barium sulfate, 1 part of nano-alumina, 0.08 parts of LS bentonite and 0.3 parts of pH adjuster are dispersed evenly at a high speed of 2000-2500 r / min, then the speed is lowered to 600-900 r / min, 31.0 parts of high TG styrene acrylic emulsion, 6.0 parts of covering emulsion, 0.3 parts of LAS255 (anti-scratch additive), 0.4 parts of post-defoaming agent, 1.0 parts of ethylene glycol (antifreeze agent), 0.4 parts of bactericidal preservative, 0.10 parts of thickener and 0.25 parts of thickening and leveling agent are added, and the mixture is stirred evenly to obtain a stain-resistant and scratch-resistant coating.

[0056] Example 2

[0057] A method for preparing a stain-resistant and scratch-resistant coating comprises the following steps:

[0058] Add 18.3 parts of water to a clean dispersion tank, place it in a stirring device, add 0.3 parts of hydrophobically modified hydroxyethyl cellulose and 0.3 parts of chitosan in sequence while stirring, add 0.3 parts of pre-defoaming agent, 0.20 parts of wetting agent, 0.8 parts of polyacrylate ammonium salt dispersant, 2.0 parts of odor-free film-forming agent after dissolution, stir evenly, increase the speed, add 24 parts of titanium dioxide, 2.0 parts of kaolin, 8.0 parts of modified precipitated barium sulfate, 3.0 parts of modified nano-precipitated barium sulfate, and 0.8 parts of nano-alumina , 0.08 parts of LS bentonite, 0.3 parts of pH adjuster, disperse evenly at a high speed of 2000-2500r / min, then lower the speed to 600-900r / min, add 31.0 parts of high TG styrene acrylic emulsion, 6.0 parts of covering emulsion, 0.4 parts of LAS255 (anti-scratch additive), 0.4 parts of post-defoaming agent, 1.0 parts of ethylene glycol, 0.4 parts of bactericidal preservative, 0.1 parts of thickener, and 0.25 parts of thickening and leveling agent, stir evenly to obtain a stain-resistant and scratch-resistant coating.

[0059] Example 3

[0060] A method for preparing a stain-resistant and scratch-resistant coating comprises the following steps:

[0061] Add 15.2 parts of water to a clean dispersion tank, place it in a stirring device, and add 0.3 parts of hydrophobically modified hydroxyethyl cellulose and 0.5 parts of chitosan in sequence while stirring. After dissolving, add 0.3 parts of pre-defoaming agent, 0.20 parts of wetting agent, 0.8 parts of polyacrylate ammonium salt dispersant, 2.0 parts of odor-free film-forming agent, stir evenly, increase the speed, add 24 parts of titanium dioxide, 1.0 parts of kaolin, 6.0 parts of modified precipitated barium sulfate, 6.0 parts of modified nano-precipitated barium sulfate, and 0.8 parts of nano-alumina. , 0.1 parts of LS bentonite, 0.3 parts of pH adjuster, disperse evenly at a high speed of 2000-2500r / min, then lower the speed to 600-900r / min, add 34.0 parts of high TG styrene acrylic emulsion, 6.0 parts of covering emulsion, 0.3 parts of LAS255 (anti-scratch additive), 0.4 parts of post-defoaming agent, 1.0 parts of ethylene glycol, 0.4 parts of bactericidal preservative, 0.1 parts of thickener, 0.25 parts of thickening and leveling agent, stir evenly to obtain a stain-resistant and scratch-resistant coating.

[0062] Comparative Example 1 (without chitosan)

[0063] Add 17 parts of water to a clean dispersion tank, place it in a stirring device, add 0.3 parts of hydrophobically modified hydroxyethyl cellulose while stirring, add 0.3 parts of pre-defoaming agent, 0.20 parts of wetting agent, 0.8 parts of polyacrylate ammonium salt dispersant, 2.0 parts of odor-free film-forming agent after dissolving, stir evenly, increase the speed, add 24 parts of titanium dioxide, 1.0 parts of kaolin, 9.0 parts of modified precipitated barium sulfate, 4.5 parts of modified nano-precipitated barium sulfate, 1.0 parts of nano-alumina, LS swelling agent. Add 0.08 parts of soil and 0.3 parts of pH regulator, disperse evenly at a high speed of 2000-2500r / min, then lower the speed to 600-900r / min, add 31.0 parts of high TG styrene acrylic emulsion, 6.0 parts of covering emulsion, 0.3 parts of LAS255 (anti-scratch aid), 0.4 parts of post-defoaming agent, 1.0 parts of ethylene glycol, 0.4 parts of bactericidal preservative, 0.20 parts of thickener and 0.25 parts of thickening and leveling agent, stir evenly to obtain the coating.

[0064] Comparative Example 2 (without adding nano oxide)

[0065] Add 17.4 parts of water to a clean dispersion tank, place it in a stirring device, add 0.3 parts of hydrophobically modified hydroxyethyl cellulose and 0.5 parts of chitosan while stirring, add 0.3 parts of pre-defoaming agent, 0.20 parts of wetting agent, 0.8 parts of polyacrylate ammonium salt dispersant, 2.0 parts of odor-free film-forming agent after dissolution, stir evenly, increase the speed, add 24 parts of titanium dioxide, 1.0 parts of kaolin, 13.5 parts of modified precipitated barium sulfate, and 0.1 parts of LS bentonite , 0.3 parts of pH regulator, disperse evenly at a high speed of 2000-2500r / min, then lower the speed to 600-900r / min, add 31.0 parts of high TG styrene acrylic emulsion, 6.0 parts of covering emulsion, 0.3 parts of LAS255 (anti-scratch additive), 0.4 parts of post-defoaming agent, 1.0 parts of ethylene glycol, 0.4 parts of bactericidal preservative, 0.20 parts of thickener, 0.25 parts of thickening and leveling agent, stir evenly to obtain the coating.

[0066] Comparative Example 3 (without precipitation of barium sulfate)

[0067] Add 18.2 parts of water to a clean dispersion tank, place it in a stirring device, add 0.3 parts of hydrophobically modified hydroxyethyl cellulose and 0.3 parts of chitosan in sequence while stirring, add 0.3 parts of pre-defoaming agent, 0.20 parts of wetting agent, 0.8 parts of polyacrylate ammonium salt dispersant, 2.0 parts of odor-free film-forming agent after dissolving, stir evenly, increase the speed, add 24 parts of titanium dioxide, 13.0 parts of kaolin, 1.0 parts of nano alumina, pH adjustment Add 0.3 parts of agent, disperse evenly at a high speed of 2000-2500 r / min, then lower the speed to 600-900 r / min, add 31.0 parts of high TG styrene acrylic emulsion, 6.0 parts of covering emulsion, 0.4 parts of LAS255 (anti-scratch additive), 0.4 parts of post-defoaming agent, 1.0 parts of ethylene glycol, 0.4 parts of bactericidal preservative, 0.20 parts of thickener and 0.25 parts of thickening and leveling agent, and stir evenly to obtain the coating.

[0068] Comparative Example 4 (using ordinary styrene acrylic emulsion, no anti-scratch agent, and sodium salt dispersant)

[0069] Add 17.0 parts of water to a clean dispersion tank, place it in a stirring device, add 0.3 parts of hydrophobically modified hydroxyethyl cellulose and 0.3 parts of chitosan in sequence while stirring, add 0.3 parts of pre-defoaming agent, 0.20 parts of wetting agent, 0.8 parts of sodium polyacrylate dispersant, 2.0 parts of odor-free film-forming agent after dissolving, stir evenly, increase the speed, add 24 parts of titanium dioxide, 1.0 parts of kaolin, 9.0 parts of modified precipitated barium sulfate, 4.5 parts of modified nano-precipitated barium sulfate 1 part, 1.0 part, nano alumina, 0.08 part, LS bentonite, 0.3 part, pH adjuster, disperse evenly at a high speed of 2000-2500r / min, then lower the speed to 600-900r / min, add 31.0 parts of ordinary styrene acrylic emulsion, 6.0 parts of covering emulsion, 0.4 part of post-defoaming agent, 1.0 part of ethylene glycol, 0.4 part of bactericidal preservative, 0.10 part of thickener, 0.25 part of thickening and leveling agent, stir evenly to obtain the coating.

[0070] Comparative Example 5 (without anti-scratch additive)

[0071] Add 17.0 parts of water to a clean dispersion tank, place it in a stirring device, add 0.3 parts of hydrophobically modified hydroxyethyl cellulose and 0.3 parts of chitosan in sequence while stirring, add 0.3 parts of pre-defoaming agent, 0.20 parts of wetting agent, 0.8 parts of polyacrylate ammonium salt dispersant, 2.0 parts of odor-free film-forming agent after dissolving, stir evenly, increase the speed, add 24 parts of titanium dioxide, 1.0 parts of kaolin, 9.0 parts of modified precipitated barium sulfate, 4.5 parts of modified nano-precipitated barium sulfate 1 part, 1.0 part, nano alumina, 0.08 part, LS bentonite, 0.3 part, pH adjuster, disperse evenly at a high speed of 2000-2500r / min, then lower the speed to 600-900r / min, add 31.0 parts of high TG styrene acrylic emulsion, 6.0 parts of covering emulsion, 0.4 parts of post-defoaming agent, 1.0 part of ethylene glycol, 0.4 parts of bactericidal preservative, 0.10 parts of thickener, 0.25 parts of thickening and leveling agent, stir evenly to obtain the coating.

[0072] Comparative Example 6 (using commercially available modified nano-precipitated barium sulfate, i.e., modified nano-precipitated barium sulfate from Shaanxi Fuhua)

[0073] Add 16.5 parts of water to a clean dispersion tank, place it in a stirring device, add 0.3 parts of hydrophobically modified hydroxyethyl cellulose and 0.5 parts of chitosan in sequence while stirring, add 0.3 parts of pre-defoaming agent, 0.20 parts of wetting agent, 0.8 parts of polyacrylate ammonium salt dispersant, 2.0 parts of odor-free film-forming agent after dissolution, increase the speed after stirring evenly, add 24 parts of titanium dioxide, 1.0 parts of kaolin, 9.0 parts of modified precipitated barium sulfate, 4.5 parts of commercially available modified nano-precipitated barium sulfate, and nano-alumina. 1 part, LS bentonite 0.08 part, pH adjuster 0.3 part, disperse evenly at a high speed of 2000-2500r / min, then lower the speed to 600-900r / min, add high TG styrene acrylic emulsion 31.0 parts, covering emulsion 6.0 parts, LAS255 (anti-scratch aid) 0.3 parts, post-defoaming agent 0.4 parts, ethylene glycol 1.0 parts, bactericidal preservative 0.4 parts, thickener 0.10 parts, thickening and leveling agent 0.25 parts, stir evenly to obtain the coating.

[0074] Experiments and Results

[0075] According to the technical requirements of topcoat in GB / T9756-2018 "Synthetic resin emulsion interior wall paint", the various technical indicators of the coatings obtained in Examples 1-3 and Comparative Examples 1-6 were tested, the stain resistance test was based on the industry general standard HG / T4756-2014 "Interior wall stain-resistant latex paint" detection, the adhesion test was based on the GB / T 9286-2021 cross-cut method, and the hardness was tested according to GB / T6739-2022.

[0076] Table 1 Test data of various embodiments 1-3

[0077]

[0078] Table 2 Test data of comparative examples 1-6

[0079]

[0080] It can be seen from the data results in the table that the comprehensive stain resistance level and anti-scratch effect of the stain and scratch resistant coatings of Examples 1 to 3 are relatively high in terms of adhesion and hardness index, the number of wash resistance reaches more than 60,000 times, the hardness reaches more than 2H, and the adhesion with the substrate reaches below level 0; Example 1 is the best embodiment, and the ratio of modified precipitated barium sulfate and modified nano-precipitated barium sulfate, and the ratio of emulsion to filler relative to Example 1 can affect the adhesion of the coating to the paint film and the hardness of the paint film to a certain extent; Comparative Examples 1-2 do not add chitosan and nano-oxides, and the stain resistance, hardness and adhesion of the paint film are significantly reduced, thereby reducing the stain resistance and anti-scratch performance; Comparative Example 3 does not use precipitated barium sulfate, and the hardness of the paint film is significantly reduced; Comparative Examples 4-5 use general styrene-acrylic emulsions without anti-scratch additives, use polycarboxylic acid sodium salt dispersants, and only do not use anti-scratch additives, and the overall stain resistance and hardness and anti-scratch performance of the paint film are significantly reduced. Comparative Example 6 is relative to Example 1. The modified precipitated barium sulfate generally available on the market also has a significant effect on the adhesion and hardness performance of the final finished product.

[0081] In summary, the stain-resistant and scratch-resistant coating formula provided by the present invention is scientific and reasonable by combining the advantages and synergistic effects of various raw materials, has a simple preparation process, is suitable for large-scale production and promotion in existing coating factories, and has broad market prospects.

[0082] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A stain-resistant and scratch-resistant coating, characterized in that: The composition comprises the following components in parts by weight: 0.3-0.8 parts of cellulose, 0.2-1.0 parts of chitosan, 22-26 parts of titanium dioxide, 0.5-3 parts of kaolin, 10-15 parts of precipitated barium sulfate, 0.05-0.3 parts of LS bentonite, 0.5-1.5 parts of nano-alumina, 30-38 parts of styrene-acrylic emulsion, 6 parts of covering emulsion, 0.2-1.0 parts of anti-scratch additive, 5.0-8.0 parts of additives, 15-20 parts of water; The auxiliary agents include dispersants, wetting agents, pre-defoaming agents, pH regulators, film-forming aids, post-defoaming agents, antifreeze agents, bactericidal preservatives, and thickeners.

2. The stain-resistant and scratch-resistant coating according to claim 1, characterized in that: The cellulose is hydrophobically modified hydroxyethyl cellulose.

3. The stain-resistant and scratch-resistant coating according to claim 1, characterized in that: The relative molecular weight of the chitosan is 10,000 to 30,000; the particle size of the nano-alumina is 20 to 60 nm.

4. The stain-resistant and scratch-resistant coating according to claim 1, characterized in that: The precipitated barium sulfate is a mixture of modified precipitated barium sulfate and modified nano-precipitated barium sulfate, wherein the mass ratio of the modified precipitated barium sulfate to the modified nano-precipitated barium sulfate is (1-3):1; the particle size of the modified precipitated barium sulfate is 1250 mesh, and the particle size of the modified nano-precipitated barium sulfate is 30-400nm.

5. The stain-resistant and scratch-resistant coating according to claim 4, characterized in that: The preparation method of the modified nano-precipitated barium sulfate is as follows: micron-scale precipitated barium sulfate is configured into a slurry with a solid content of 40-60wt%, and the precipitated barium sulfate slurry is obtained by grinding; the precipitated barium sulfate slurry is added into a reaction kettle, and a modified coating agent of 1-3wt% of the mass of the precipitated barium sulfate and a starch modifier of 4-8wt% of the mass of the precipitated barium sulfate are added, and then homogenized, and then filtered, washed, dried and crushed to obtain modified nano-precipitated barium sulfate powder; The modified coating agent is a nano-silicon dioxide slurry with a concentration of 100 g / L, and the starch modifier is sodium dodecylbenzene sulfonate.

6. The stain-resistant and scratch-resistant coating according to claim 1, characterized in that: The titanium dioxide, kaolin and precipitated barium sulfate are all pigments and fillers; the pigments and fillers account for 35-40% of the mass of the anti-fouling and anti-scratch coating; the mass ratio of the precipitated barium sulfate to the pigments and fillers is (0.2-0.4):

1.

7. The stain-resistant and scratch-resistant coating according to claim 6, characterized in that: The styrene acrylic emulsion is a high TG emulsion with a TG range of 40 to 42° C. The mass ratio of the styrene acrylic emulsion to the pigment and filler is (0.75 to 1.0):

1.

8. The stain-resistant and scratch-resistant coating according to claim 1, characterized in that: The anti-scratch additive is a silicone aqueous dispersion with an ultra-high molecular weight, the molecular weight of which is greater than 1 million.

9. The stain-resistant and scratch-resistant coating according to claim 1, characterized in that: The dispersant is ammonium polyacrylate; the auxiliary agent includes the following components in parts by weight: 0.6-0.9 parts of ammonium polyacrylate dispersant, 0.1-0.3 parts of wetting agent, 0.2-0.3 parts of pre-defoaming agent, 0.2-0.4 parts of pH regulator, 1-3 parts of film-forming auxiliary agent, 0.2-0.5 parts of post-defoaming agent, 0.8-1.5 parts of antifreeze agent, 0.3-0.5 parts of bactericidal preservative, and 0.2-0.5 parts of thickener.

10. A method for preparing a stain-resistant and scratch-resistant coating according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) adding water to a stirring device, and sequentially adding cellulose and chitosan while stirring; after the cellulose and chitosan are dissolved, adding a wetting agent, a dispersant, a pre-defoaming agent, and a film-forming aid, and stirring; (2) adding titanium dioxide, kaolin, precipitated barium sulfate, nano-alumina, LS bentonite and pH adjuster and stirring, then adding styrene acrylic emulsion, covering emulsion, anti-scratch additive, post-defoaming agent, antifreeze agent, bactericidal preservative, thickener, stirring evenly to obtain a finished product of anti-fouling and anti-scratch coating.

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