A thick paste type composite imitation stone paint and preparation method thereof

Abstract

The present invention relates to the technical field of stone-like paint research and development, and discloses a thick paste type composite stone-like paint and a preparation method, the thick paste type composite stone-like paint is composed of a composite primer, a stone-like paint main paint, and a finishing paint, wherein the preparation method of the finishing paint includes: synthesizing a light-stable coupling monomer and a light stabilizer; modifying titanium dioxide nanoparticles using a light-stable coupling monomer and / or a light stabilizer to prepare light-stable titanium dioxide nanoparticles; based on π-π stacking, the light-stable titanium dioxide nanoparticles are subjected to a composite treatment of graphene nanosheets modified with trimethoxy (2-phenylethyl) silane to prepare a graphene-titanium dioxide composite material; modifying the finishing paint by the graphene-titanium dioxide composite material to prepare a composite finishing paint. The present invention provides a method for preparing a finishing paint, and prepares a finishing paint with excellent weather resistance.

Description

Technical Field

[0001] The invention relates to the technical field of research and development of stone-like paints, in particular to a thick paste type composite stone-like paint and a preparation method thereof. Background Art

[0002] The decorative effect of imitation stone paint is comparable to that of stone, and it is easier to shape various arts than stone. It has rich texture, high hardness and economical cost, so it is widely used. The common problem of the traditional standard construction process of imitation stone paint (mortar, putty, primer, intermediate paint, imitation stone paint main paint, topcoat) and the traditional process for renovation of old walls such as ceramic tile mosaics (interface agent, anti-cracking mortar, mesh cloth, flexible putty, primer, intermediate paint, imitation stone paint main paint, topcoat) is that there are too many construction processes.

[0003] Since imitation stone paint is exposed to the outside, it is easily affected by environmental and physical factors, such as ultraviolet rays, weathering, water vapor and mechanical wear, which may cause the surface to peel, crack and have color difference. In order to protect the surface of imitation stone paint and increase weather resistance, it is recommended to use topcoat for protection after applying imitation stone paint.

[0004] At present, the main way to increase the weather resistance of imitation stone paint is to add anticorrosive additives and light stabilizing additives to the topcoat. For example, the Chinese patent with publication number CN115340776A discloses the use of 2'-dihydroxy-5,5'-dichlorodiphenylmethane as an anticorrosive agent to prepare a water-based, multi-color, high-imitation granite colored stone paint texture paint to achieve mildew and anticorrosion performance; the Chinese patent with publication number CN113444414A discloses a limestone-like high weather-resistant antibacterial paint and its preparation method, which significantly improves the weather resistance of the paint by adding inorganic ultraviolet light shielding agents such as nano zinc oxide and nano titanium dioxide. In addition, there are reports in the prior art on using graphene to improve the weather resistance of paint. Summary of the invention

[0005] In view of the defects of the prior art, the present invention provides a thick paste type composite imitation stone paint, which consists of a composite primer, a main imitation stone paint and a finishing paint. No matter whether the thick paste type composite imitation stone paint is used on new or old walls, only mortar, a composite primer, a main imitation stone paint and a finishing paint are needed, thereby effectively overcoming the technical defects of alkali efflux, insufficient thickness, obvious thick imitation stone feeling, poor weather resistance and high cost to achieve the same effect. Among them, the composite primer provides the functions of base treatment and leveling, adhesion to the substrate, product thickness, modeling, crack resistance, waterproofing, coloring and the like; the main imitation stone paint provides the functions of imitation stone color, stone texture, weather resistance, waterproofing and crack resistance and the like; the finishing paint provides the functions of weather resistance, waterproofing and anti-fouling and the like; and further research and development is carried out on the weather resistance of the finishing paint to provide a finishing paint with excellent weather resistance.

[0006] A thick paste type composite stone-imitation paint, the thick paste type composite stone-imitation paint is composed of a composite primer, a stone-imitation paint main paint, and a topcoat. The preparation method of the topcoat is as follows:

[0007] Step 1: Synthesis of photostable coupling monomers;

[0008] The photostable coupling monomer is a photostable coupling monomer M1, and its chemical structure is:

[0009]

[0010] Step 2: modifying titanium dioxide nanoparticles with a photostable coupling monomer or modifying titanium dioxide nanoparticles with a photostable coupling monomer and a photostabilizer to prepare photostable titanium dioxide nanoparticles; based on the π-π stacking effect, compounding the photostable titanium dioxide nanoparticles with graphene nanosheets modified with trimethoxy(2-phenylethyl)silane to prepare a graphene-titanium dioxide composite material, which is a weathering modifier;

[0011] Step three: prepare a topcoat, which is obtained by uniformly mixing 55-75wt% of a base paint, 5-15wt% of a protective adhesive and 10-40wt% of a continuous phase; the base paint contains a weathering modifier in an amount of 3-8wt%.

[0012] Preferably, the photostable coupling monomer is a photostable coupling monomer M2, and its chemical structure is:

[0013]

[0014] Preferably, the chemical structural formula of the light stabilizer is:

[0015]

[0016] Preferably, the preparation method of the photostable coupling monomer M1 is:

[0017] Step S4-1: generating sodium 1,3-propanedithiol by an acid-base neutralization reaction between 1,3-propanedithiol and sodium hydroxide;

[0018] Step S4-2: using the Williamson ether synthesis reaction mechanism, a nucleophilic substitution reaction is carried out between sodium 1,3-propanedithiolate and 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol in equal molar equivalents, followed by acidification with an inorganic proton acid to generate thiopropyl UV-326-based thiol;

[0019] Step S4-3: alkaline substances catalyze the nucleophilic addition reaction between the thiol functional group of thiopropyl UV-326 mercaptan and the alkenyl functional group of the silane coupling agent YDH-171 to generate a light-stable coupling monomer M1.

[0020] Preferably, the preparation method of the light-stable coupling monomer M2 is:

[0021] Step S5-1: generating sodium 1,4-benzenedimethanethiol by an acid-base neutralization reaction between 1,4-benzenedimethanethiol and sodium hydroxide;

[0022] Step S5-2: using the Williamson ether synthesis reaction mechanism, a nucleophilic substitution reaction is carried out with the same molar equivalent of sodium 1,4-benzenedimethanethiolate and 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol, followed by acidification with an inorganic proton acid to generate thiophenyl UV-326-yl thiol;

[0023] Step S5-3: alkaline substances catalyze the nucleophilic addition reaction between the thiol functional group of thiophenyl UV-326-based thiol and the alkenyl functional group of the silane coupling agent YDH-171 to generate a light-stable coupling monomer M2.

[0024] Preferably, the inorganic protonic acid is one of hydrochloric acid, sulfuric acid and phosphoric acid;

[0025] Preferably, the alkaline substance is one of sodium hydroxide, sodium carbonate and sodium ethoxide.

[0026] Preferably, the preparation method of the light stabilizer is: utilizing the Williamson ether synthesis reaction mechanism, a nucleophilic substitution reaction is carried out between 1 molar equivalent of sodium 1,3-propanedithiolate and 2 molar equivalents of 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol to generate the light stabilizer.

[0027] Preferably, the formula of the base paint is: 10-20wt% deionized water, 10-20wt% resin, 5-10wt% cellulose, 20-40wt% filler, 1-5wt% heat insulating agent, 3-8wt% weathering modifier, 0.1-1wt% antifreeze agent, 0.1-1wt% film-forming aid, 0.1-1wt% pH regulator, 0.1-1wt% dispersant, 0.1-1wt% wetting agent, 10-30wt% base paint emulsion and 1-3wt% color powder;

[0028] The resin is an organosilicon-modified polyester resin emulsion;

[0029] The cellulose is one or a combination of hydroxyethyl cellulose and hydroxyethyl methyl cellulose;

[0030] The filler is one or a combination of kaolin, quartz sand, talcum powder, and calcium carbonate;

[0031] The heat insulating agent is one or a combination of titanium dioxide, mica flakes, and boron nitride;

[0032] The antifreeze agent is one or a combination of propylene glycol, ethylene glycol, polyethylene glycol, and polypropylene glycol;

[0033] The film-forming aid is alcohol ester dodecahydrate;

[0034] The pH regulator is one or a combination of 2-amino-2-methyl-1-propanol and N,N-dimethylethanolamine;

[0035] The dispersant is an ammonium polyacrylate dispersant;

[0036] The wetting agent is octylphenol polyoxyethylene ether;

[0037] The base paint emulsion is a silicone-acrylic emulsion;

[0038] The toner is iron red.

[0039] Preferably, the formula of the protective glue solution is: 90-95wt% deionized water, 3-8wt% protective glue and 0.1-2wt% protective glue auxiliary agent;

[0040] The protective glue is one or a combination of magnesium aluminum silicate and magnesium lithium silicate;

[0041] The protective glue auxiliary agent is one or a combination of inorganic bentonite and xanthan gum.

[0042] Preferably, the formula of the continuous phase is: 20-40wt% deionized water, 1-5wt% weathering modifier, 0.5-2wt% thickener, 1-5wt% crosslinking agent, 1-5wt% defoamer and 50-70wt% continuous phase emulsion;

[0043] The thickener is polyacrylate;

[0044] The cross-linking agent is one or a combination of polycarbodiimide and N,N-methylenebisacrylamide.

[0045] The defoamer is an organosilicon defoamer;

[0046] The continuous phase emulsion is acrylic emulsion.

[0047] Preferably, the formula of the base paint is: 10-20wt% deionized water, 10-20wt% organosilicon modified polyester resin emulsion, 2-5wt% hydroxyethyl cellulose, 2-5wt% hydroxyethyl methyl cellulose, 5-15wt% kaolin, 15-25wt% quartz sand, 1-5wt% titanium dioxide, 3-8wt% graphene-titanium dioxide composite material, 0.1-1wt% propylene glycol, 0.1-1wt% alcohol ester dodecyl, 0.1-1wt% 2-amino-2-methyl-1-propanol, 0.1-1wt% polyacrylate ammonium salt dispersant, 0.1-1wt% octylphenol polyoxyethylene ether, 10-30wt% silicone acrylic emulsion and 1-3wt% iron red.

[0048] Preferably, the formula of the protective colloid is: 90-95wt% deionized water, 3-8wt% magnesium aluminum silicate and 0.1-2wt% inorganic bentonite.

[0049] Preferably, the formula of the continuous phase is: 20-40wt% deionized water, 1-5wt% graphene-titanium dioxide composite material, 0.5-2wt% polyacrylate, 1-5wt% polycarbodiimide, 1-5wt% silicone defoamer and 50-70wt% acrylic emulsion.

[0050] Beneficial effects:

[0051] The present invention synthesizes two novel light-stable coupling monomers and a novel light stabilizer, uses the light-stable coupling monomers and / or the novel light stabilizer to modify graphene and titanium dioxide to obtain a graphene-titanium dioxide composite material, introduces the graphene-titanium dioxide composite material into a topcoat to obtain a topcoat with excellent weather resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The synthetic route for the photostable coupling monomer M1;

[0053] Figure 2 is the hydrogen spectrum of the photostable coupling monomer M1;

[0054] Figure 3 is the hydrogen spectrum of the photostable coupling monomer M2;

[0055] Figure 4 It is a synthetic route for light stabilizers;

[0056] Figure 5 is the hydrogen spectrum of the light stabilizer;

[0057] Figure 6 These are the performance test results of the topcoat. DETAILED DESCRIPTION

[0058] The present invention combines the properties of graphene and nano-titanium dioxide by a newly developed light-stable coupling monomer and / or a novel light stabilizer to prepare a graphene-titanium dioxide (GO-TiO2) composite material, which is used in topcoat to improve weather resistance.

[0059] Experimental Example 1:

[0060] Prepare the photostable coupling monomer M1, such as Figure 1 As shown, the synthesis steps are as follows:

[0061] Step 1: 1,3-propanedithiol and sodium hydroxide undergo an acid-base neutralization reaction to generate sodium 1,3-propanedithiol;

[0062] Step 2: Using the Williamson ether synthesis reaction mechanism, a nucleophilic substitution reaction is carried out by reacting the same molar equivalent of sodium 1,3-propanedithiolate and 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol (ultraviolet absorber UV-326), followed by acidification with an inorganic proton acid to generate thiopropyl UV-326-based thiol;

[0063] The inorganic protonic acid is one of hydrochloric acid, sulfuric acid and phosphoric acid; hydrochloric acid is selected in this experimental example;

[0064] Step 3: alkaline substances catalyze the nucleophilic addition reaction between the thiol functional group of thiopropyl UV-326 mercaptan and the alkenyl functional group of the silane coupling agent YDH-171 (vinyl trimethoxy silane) to generate a light-stable coupling monomer M1;

[0065] The alkaline substance is one of sodium hydroxide, sodium carbonate and sodium ethoxide; sodium ethoxide is selected in this experimental example;

[0066] The specific experimental steps of the photostable coupling monomer M1 are as follows:

[0067] (1) 1.3 g of 1,3-propanedithiol and 40 mL of 0.5 mol / L sodium hydroxide aqueous solution were added to a three-necked flask, and the temperature was raised to 40° C. for reaction for 2 h under mechanical stirring, and the solvent was removed by rotary evaporation and dried to obtain sodium 1,3-propanedithiol;

[0068] (2) 0.8 g of sodium 1,3-propanedithiolate and 20 mL of anhydrous ethanol were added to a three-necked flask, and stirred at room temperature under mechanical stirring until all the solution was dissolved. Then, 30 mL of 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol solution (prepared with 1.6 g of 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol and 30 mL of anhydrous ethanol) was added dropwise to the three-necked flask, and the temperature was raised to 80° C. and refluxed for 6 h. After cooling to room temperature, 20 mL of 0.1 mol / L hydrochloric acid aqueous solution was added to the three-necked flask, and the mixture was stirred at room temperature for 1 h. The mixture was washed with deionized water, extracted with ether, dried over anhydrous magnesium sulfate, and ether was removed by rotary evaporation. The mixture was dried in vacuo to obtain thiopropyl UV-326-yl thiol.

[0069] (3) 1.0 g of thiopropyl UV-326 mercaptan, 0.5 g of sodium ethoxide and 30 mL of anhydrous ethanol were added to a three-necked flask and stirred at room temperature until all dissolved. Then, 20 mL of silane coupling agent YDH-171 solution (prepared with 0.4 g of silane coupling agent YDH-171 and 20 mL of anhydrous ethanol) was added dropwise to the three-necked flask. The mixture was heated to 65° C. and stirred for 4 h. The mixture was cooled to room temperature, washed with deionized water, dried with anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. The mixture was dried in vacuo to obtain a light-stable coupling monomer M1. The chemical structure and hydrogen spectrum (test conditions: 400 Hz, CDCl3) characterization results are shown in FIG. Figure 2 shown.

[0070] Experimental Example 2:

[0071] The light-stable coupling monomer M2 was prepared, and the synthesis steps were as follows:

[0072] Step 1: 1,4-benzenedimethanethiol and sodium hydroxide undergo an acid-base neutralization reaction to generate sodium 1,4-benzenedimethanethiolate;

[0073] Step 2: using the Williamson ether synthesis reaction mechanism, a nucleophilic substitution reaction is carried out with the same molar equivalent of sodium 1,4-benzenedimethanethiolate and 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol, followed by acidification with an inorganic proton acid to generate thiophenyl UV-326-based thiol;

[0074] The inorganic protonic acid is one of hydrochloric acid, sulfuric acid and phosphoric acid; hydrochloric acid is selected in this experimental example;

[0075] Step 3: alkaline substances catalyze the nucleophilic addition reaction between the thiol functional group of thiophenyl UV-326-based thiol and the olefinic functional group of the silane coupling agent YDH-171 to generate a light-stable coupling monomer M2;

[0076] The alkaline substance is one of sodium hydroxide, sodium carbonate and sodium ethoxide; sodium ethoxide is selected in this experimental example;

[0077] The specific experimental steps of the photostable coupling monomer M2 are as follows: only 1.9 g of 1,4-benzenedimethanethiol is used to replace 1.3 g of 1,3-propanedithiol in the photostable coupling monomer M1, and the rest of the parts are the same, to prepare the photostable coupling monomer M2, and its chemical structure and hydrogen spectrum (test conditions: 400 Hz, CDCl3) characterization results are as follows Figure 3 shown.

[0078] Experimental Example 3:

[0079] Preparation of light stabilizers, such as Figure 4 As shown, the synthesis method is as follows: using the Williamson ether synthesis reaction mechanism, a light stabilizer is generated by a nucleophilic substitution reaction between 1 molar equivalent of 1,3-propanedithiolate sodium and 2 molar equivalents of 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol. The specific experimental steps are as follows: 0.4 g of 1,3-propanedithiolate sodium and 20 mL of anhydrous ethanol are added to a three-necked flask, and stirred at room temperature until all dissolved under mechanical stirring, and then 30 mL of 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol solution (composed of 1.6 g of 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol and 30 mL of anhydrous ethanol), heated to 80°C and refluxed for 6 hours, washed with deionized water, extracted with ether, dried with anhydrous magnesium sulfate, and rotary evaporated to remove ether, and vacuum dried to obtain a light stabilizer. Its chemical structure and hydrogen spectrum (test conditions: 400 Hz, CDCl3) characterization results are shown as follows Figure 5 shown.

[0080] Embodiment 1:

[0081] (1) Preparation of modified titanium dioxide I: Titanium dioxide nanoparticles were modified with a light-stable coupling monomer M1 to obtain modified titanium dioxide I. The specific experimental steps were as follows: 1 g of titanium dioxide nanoparticles, 80 mL of anhydrous ethanol and 20 mL of deionized water were added to a beaker, ultrasonically treated for 10 min, heated to 40°C, and then 2 g of the light-stable coupling monomer M1 was added to the beaker. The mixture was stirred for 8 h and centrifuged. The mixture was repeatedly centrifuged and washed with anhydrous ethanol and deionized water, and vacuum dried to obtain modified titanium dioxide I.

[0082] Preparation of graphene-titania composite material I: Graphene nanosheets modified with silane coupling agent TMPES were modified with modified titanium dioxide I by π-π stacking effect to obtain graphene-titania composite material I. The specific experimental steps are as follows: 3g of modified titanium dioxide I, 5g of graphene nanosheets modified with silane coupling agent TMPES and 100mL of anhydrous ethanol were added to a beaker, ultrasonically treated for 30min, heated to 60°C and stirred for 5h, centrifuged, and repeatedly centrifuged and washed with anhydrous ethanol and deionized water in turn, and vacuum dried to obtain graphene-titania composite material I;

[0083] (2) Preparation of modified titanium dioxide II: Titanium dioxide nanoparticles are modified with a photostable coupling monomer M2 to obtain modified titanium dioxide II. The specific experimental steps are: only the photostable coupling monomer M2 is used to replace the photostable coupling monomer M1 in the photostable modified titanium dioxide I, and the rest of the parts are the same, to prepare modified titanium dioxide II;

[0084] Preparation of graphene-titania composite material II: using π-π stacking effect, the graphene nanosheets modified by the silane coupling agent TMPES are modified by modified titanium dioxide II to obtain graphene-titania composite material II, and the specific experimental steps are: only the modified titanium dioxide II is used to replace the modified titanium dioxide I in the graphene-titania composite material I, and the rest of the parts are the same, so as to prepare the graphene-titania composite material II;

[0085] (3) Preparation of modified titanium dioxide III: Titanium dioxide nanoparticles are modified by using a photostable coupling monomer M1 and a photostabilizer to obtain modified titanium dioxide III. The specific experimental steps are as follows: only 1 g of the photostabilizer coupling monomer M1 and 1 g of the photostabilizer are used to replace 2 g of the photostabilizer coupling monomer M1 in the photostabilizer modified titanium dioxide I, and the rest of the components are the same, to prepare modified titanium dioxide III.

[0086] Preparation of graphene-titania composite material III: using π-π stacking effect, the graphene nanosheets modified by the silane coupling agent TMPES are modified by modified titanium dioxide III to obtain graphene-titania composite material III, and the specific experimental steps are: only the modified titanium dioxide III is used to replace the modified titanium dioxide I in the graphene-titania composite material I, and the other parts are the same, so as to prepare the graphene-titania composite material III;

[0087] (4) Preparation of graphene-titanium dioxide blended material: physically mixing titanium dioxide nanoparticles and graphene nanosheets to obtain a graphene-titanium dioxide blended material, wherein the specific experimental steps are as follows: adding 1 g of titanium dioxide nanoparticles, 3 g of graphene nanosheets and 100 mL of anhydrous ethanol into a beaker, ultrasonically treating for 30 min, centrifuging and vacuum drying to obtain a graphene-titanium dioxide blended material;

[0088] Among them, the preparation method of graphene nanosheets modified with silane coupling agent TMPES is as follows: 3g of graphene nanosheets, 80mL of anhydrous ethanol and 20mL of deionized water are added to a beaker, ultrasonically treated for 10 minutes, heated to 40°C, and then 2g of alkane coupling agent TMPES (trimethoxy(2-phenylethyl)silane) is added to the beaker, stirred for reaction for 6 hours, centrifuged, and repeatedly centrifuged and washed with anhydrous ethanol and deionized water in turn, and vacuum dried to obtain graphene nanosheets modified with silane coupling agent TMPES.

[0089] Embodiment 2:

[0090] The preparation of composite finish paint comprises the following steps:

[0091] Step 1: preparing a base paint: according to the formula of the base paint in Table 1, deionized water, silicone-modified polyester resin emulsion, hydroxyethyl cellulose, hydroxyethyl methyl cellulose, kaolin, varnish, titanium dioxide, graphene-titanium dioxide composite material, propylene glycol, alcohol ester dodecahydrate, 2-amino-2-methyl-1-propanol, polyacrylate ammonium salt dispersant, octylphenol polyoxyethylene ether and silicone-acrylic emulsion are put into a disperser and mixed, stirred at 1000 r / min for 60 min, iron red is added, and stirring is continued at 1000 r / min for 30 min to prepare a base paint;

[0092] Step 2: preparing a protective colloid: according to the formula of the protective colloid in Table 2, deionized water, magnesium aluminum silicate and inorganic bentonite were mixed in a disperser, and stirred at 200 r / min for 30 min to prepare a protective colloid;

[0093] Step 3: preparing a continuous phase: according to the formula of the continuous phase in Table 3, deionized water, graphene-titanium dioxide composite material, polyacrylate, polycarbodiimide, silicone defoamer and acrylic emulsion were mixed in a disperser, and stirred at 800 r / min for 60 min to prepare a continuous phase;

[0094] Step 4: Mix the base paint and the protective glue solution, stir at 800 r / min for 60 min, then add the continuous phase, keep stirring at 800 r / min for 60 min, and prepare a composite topcoat;

[0095] Among them, the mass ratio of base paint, protective adhesive and continuous phase is 6:1:3;

[0096] Table 1 Formula of base paint

[0097]

[0098]

[0099] Table 2 Formula of protective glue

[0100] Raw material components Feeding mass (%) Deionized water 93 Magnesium Aluminum Silicate 6 Inorganic bentonite 1

[0101] Table 3 Formulation of continuous phase

[0102] Raw material components Feeding mass (%) Deionized water 31 Graphene-titanium dioxide composites 4 Polyacrylate 1 Polycarbodiimide 2 Silicone defoamer 2 Acrylic Emulsion 60

[0103] Among them, when the graphene-titania composite materials are graphene-titania composite material I, graphene-titania composite material II, and graphene-titania composite material III, respectively, composite topcoat I, composite topcoat II, and composite topcoat III are prepared, respectively; when the graphene-titania blended material is used to replace the graphene-titania composite material, a composite topcoat a is prepared; when the graphene-titania composite material is not used, a topcoat is prepared as a comparative example.

[0104] Performance Test:

[0105] The topcoat was sprayed using a PT871A adjustable pressure spray gun, and after curing at room temperature, a stone-like paint coating was formed. The performance test was carried out, and the results are shown in Table 4 and Figure 6 shown.

[0106] Table 4 Performance test results of topcoat

[0107]

[0108] By comprehensively analyzing the above experimental results, the following conclusions can be drawn:

[0109] (1) The improvement effect of graphene and nano-titanium dioxide on topcoat without modification with photostable coupling monomers is much lower than that of graphene-titanium dioxide composites modified with photostable coupling monomers;

[0110] (2) There is almost no significant difference in weather resistance of the graphene-titanium dioxide composites prepared by using the photostable coupling monomer M1 and the photostable coupling monomer M2 as modifiers;

[0111] (3) The graphene-titanium dioxide composite materials modified with photostable coupling monomers and new photostabilizers can further effectively improve the weather resistance.

Claims

1. A thick paste type composite imitation stone paint, which is composed of a composite primer, a main imitation stone paint, and a topcoat. It is characterized in that The preparation method of the finishing paint is: Step 1: Synthesis of photostable coupling monomers; The photostable coupling monomer is a photostable coupling monomer M1, and its chemical structure is: Step 2: modifying titanium dioxide nanoparticles with a photostable coupling monomer or modifying titanium dioxide nanoparticles with a photostable coupling monomer and a photostabilizer to prepare photostable titanium dioxide nanoparticles; Based on the π-π stacking effect, light-stable titanium dioxide nanoparticles are composited with graphene nanosheets modified with trimethoxy(2-phenylethyl)silane to prepare a graphene-titanium dioxide composite material, which is a weathering modifier. Step three: prepare a topcoat, which is obtained by uniformly mixing 55-75wt% of a base paint, 5-15wt% of a protective adhesive and 10-40wt% of a continuous phase; the base paint contains a weathering modifier in an amount of 3-8wt%.

2. A thick paste type composite stone-like paint according to claim 1, It is characterized in that The photostable coupling monomer is a photostable coupling monomer M2, and its chemical structure is:

3. A thick paste type composite stone-like paint according to claim 1, It is characterized in that The chemical structural formula of the light stabilizer is:

4. A thick paste type composite stone-like paint according to claim 1, It is characterized in that The preparation method of the light-stable coupling monomer M1 is as follows: Step S4-1: generating sodium 1,3-propanedithiol by an acid-base neutralization reaction between 1,3-propanedithiol and sodium hydroxide; Step S4-2: using the Williamson ether synthesis reaction mechanism, a nucleophilic substitution reaction is carried out between sodium 1,3-propanedithiolate and 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol in equal molar equivalents, followed by acidification with an inorganic proton acid to generate thiopropyl UV-326-based thiol; Step S4-3: alkaline substances catalyze the nucleophilic addition reaction between the thiol functional group of thiopropyl UV-326 mercaptan and the alkenyl functional group of the silane coupling agent YDH-171 to generate a light-stable coupling monomer M1.

5. A thick paste type composite stone-like paint according to claim 2, It is characterized in that The preparation method of the light-stable coupling monomer M2 is: Step S5-1: generating sodium 1,4-benzenedimethanethiol by an acid-base neutralization reaction between 1,4-benzenedimethanethiol and sodium hydroxide; Step S5-2: using the Williamson ether synthesis reaction mechanism, a nucleophilic substitution reaction is carried out with the same molar equivalent of sodium 1,4-benzenedimethanethiolate and 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol, followed by acidification with an inorganic proton acid to generate thiophenyl UV-326-yl thiol; Step S5-3: alkaline substances catalyze the nucleophilic addition reaction between the thiol functional group of thiophenyl UV-326-based thiol and the alkenyl functional group of the silane coupling agent YDH-171 to generate a light-stable coupling monomer M2.

6. A thick paste type composite stone-like paint according to claim 4 or 5, It is characterized in that The inorganic protonic acid is one of hydrochloric acid, sulfuric acid and phosphoric acid; The alkaline substance is one of sodium hydroxide, sodium carbonate and sodium ethoxide.

7. The thick paste composite stone-like paint according to claim 3, It is characterized in that The preparation method of the light stabilizer comprises: utilizing the Williamson ether synthesis reaction mechanism, and generating the light stabilizer by a nucleophilic substitution reaction of 1 molar equivalent of sodium 1,3-propanedithiolate and 2 molar equivalents of 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol.

8. The thick paste composite stone-like paint according to claim 1, It is characterized in that The formula of the basic paint is: 10-20wt% deionized water, 10-20wt% organosilicon modified polyester resin emulsion, 2-5wt% hydroxyethyl cellulose, 2-5wt% hydroxyethyl methyl cellulose, 5-15wt% kaolin, 15-25wt% quartz sand, 1-5wt% titanium dioxide, 3-8wt% graphene-titanium dioxide composite material, 0.1-1wt% propylene glycol, 0.1-1wt% alcohol ester dodecyl, 0.1-1wt% 2-amino-2-methyl-1-propanol, 0.1-1wt% polyacrylate ammonium salt dispersant, 0.1-1wt% octylphenol polyoxyethylene ether, 10-30wt% silicone acrylic emulsion and 1-3wt% iron red.

9. The thick paste composite stone-like paint according to claim 1, It is characterized in that The formula of the protective glue is: 90-95wt% deionized water, 3-8wt% magnesium aluminum silicate and 0.1-2wt% inorganic bentonite.

10. The thick paste composite stone-like paint according to claim 1, It is characterized in that The formula of the continuous phase is: 20-40wt% deionized water, 1-5wt% graphene-titanium dioxide composite material, 0.5-2wt% polyacrylate, 1-5wt% polycarbodiimide, 1-5wt% organosilicon defoamer and 50-70wt% acrylic emulsion.

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