White coating for building

Abstract

The invention relates to the technical field of coatings, in particular to a white coating for buildings, which comprises titanium dioxide color paste, and a preparation method of the titanium dioxide color paste comprises the following steps: mixing titanium dioxide, a humectant, an auxiliary agent and a bridging agent, and carrying out heat treatment to obtain a mixed solution, the bridging agent comprises a compound containing an epoxy group, the epoxy equivalent of the epoxy group is 130-200g / equivalent, and the heat treatment temperature is 60-80 DEG C; a first dispersing agent is added into the mixed solution and mixed, the white coating is obtained, and the first dispersing agent comprises a polymer containing an affinity group. The bridging agent and titanium dioxide are connected together through heat treatment, then the dispersing agent is added, the oleophylic end of the dispersing agent reacts with the bridging agent, the hydrophilic end of the dispersing agent is dissolved in an aqueous solution at the outer end, and the stability of the water-based pigment ink is improved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and in particular to a white coating for buildings. Background Art

[0002] Architectural decorative ink is a special ink used to decorate and protect the surface of buildings. With the advancement of technology and the demand for environmental protection, architectural decorative ink has achieved remarkable development in many aspects. Through organic polymer materials, inorganic non-metallic materials, metal materials or composite materials, the application scope of architectural decorative ink is becoming more and more extensive, including walls, floors, ceilings and other building materials. However, at present, architectural decorative ink generally focuses on adsorption and antibacterial properties, but ignores the stability of architectural decorative ink and color uniformity.

[0003] White ink with good covering properties is usually used to cover building substrates, and titanium dioxide is usually used as a pigment for the white ink. However, due to the high specific gravity of titanium dioxide inorganic pigments, when such pigments are used in low-viscosity inkjet inks, the pigment is prone to sedimentation, which becomes a problem and greatly affects the stability of the white ink. If the particle size of titanium dioxide is reduced in order to suppress the sedimentation of the pigment, the degree of sedimentation can be reduced, but there are problems such as easy deterioration of white coloring, poor covering properties, and rapid deterioration.

[0004] The prior art discloses a method for preparing a water-based UV stabilizer for exterior wall paint, which is mainly composed of nano silicon dioxide. The specific gravity of silicon dioxide is lower than that of titanium dioxide, which can prevent sedimentation. However, the whiteness of silicon dioxide is lower than that of titanium dioxide, so the white coverage of the building substrate is relatively poor. In addition, this patent increases the anti-aging performance of the paint by adding a UV stabilizer, but the stability and weather resistance of the paint are not ideal. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of poor stability, poor whiteness and high sedimentation rate of architectural coatings in the prior art, thereby providing a white architectural coating.

[0006] Another technical problem to be solved by the present invention is to overcome the defect of poor weather resistance of architectural decorative coatings in the prior art, thereby providing a white architectural coating.

[0007] On the one hand, the present invention provides a white paint for construction, including titanium dioxide color paste. The preparation method of the titanium dioxide color paste includes the following steps: mixing titanium dioxide, a humectant, an auxiliary agent and a bridging agent, and heat-treating to obtain a mixed solution, wherein the titanium dioxide includes titanium dioxide surface-modified with aluminum oxide, the bridging agent includes a compound containing an epoxy group, the epoxy equivalent of the epoxy group is 130-200 g / equivalent, and the temperature of the heat treatment is 60°C-80°C; adding a first dispersant to the mixed solution, mixing to obtain a white paint, wherein the first dispersant includes a polymer containing an affinity group.

[0008] Since there are positive and negative charges on the surface of titanium dioxide, they will attract each other due to electrostatic effects, resulting in the aggregation of titanium dioxide, which is more likely to cause sedimentation, and even cause the printing nozzle to be blocked in severe cases. The present invention connects the bridging agent and titanium dioxide together through heat treatment, and further adds a first dispersant to enhance the water solubility of the cross-linked titanium dioxide. The oleophilic end of the first dispersant reacts with the bridging agent, and the hydrophilic end is soluble in the aqueous solution at the outer end, which helps to improve the stability of the water-based pigment ink. At the same time, after the bridging agent and the dispersant are connected, the steric hindrance of the titanium dioxide particles increases. Therefore, even if the particle size of the titanium dioxide is reduced by grinding, the titanium dioxide paste provided by the present invention will not aggregate because the particle size of the titanium dioxide becomes smaller and the surface energy becomes larger.

[0009] Furthermore, the embodiment of the present invention uses alumina to modify titanium dioxide. First, the surface energy of alumina is lower than that of titanium dioxide. After modification, titanium dioxide is less likely to aggregate. Second, since alumina has a higher ability to reflect and refract light, it helps to improve the overall whiteness of white paint for buildings. Third, the chemical inertness of alumina helps to improve the weather resistance, acid and alkali resistance and other properties of white paint for buildings. Furthermore, at room temperature, epoxy resin has excellent adhesion to alumina, and under the reaction conditions of 60℃-80℃, the epoxy resin will chemically bond with the alumina on the surface of titanium dioxide after ring opening, thereby successfully connecting the epoxy resin chain to the surface of titanium dioxide.

[0010] As can be seen from the above scheme, the epoxy resin is linked to the surface of titanium dioxide to avoid aggregation between titanium dioxide. However, since the solubility of epoxy resin in water is not high, it is easy to precipitate in water-based pigment ink, affecting the stability of the ink. Therefore, the embodiment of the present invention can interact with the other end of the epoxy resin by adding a first dispersant having an affinity group polymer, which can not only enhance the water solubility of the titanium dioxide color paste, but also increase steric hindrance and play a dispersive role. Further, the long chain of the epoxy resin forms a steric hindrance, so that titanium dioxide is not easy to gather together and enhance the anti-sedimentation property. At the same time, the titanium dioxide combined with the epoxy resin has better whiteness and opacity. The epoxy resin with an epoxy equivalent of 130-200g / equivalent can react with alumina at a lower temperature. The epoxy equivalent is too low to fully encapsulate the titanium dioxide, and the epoxy equivalent is too high, which affects the flexibility of the ink.

[0011] In some embodiments, the bridging agent includes one of propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether and 2-ethylhexyl glycidyl ether. Exemplary, the specific product models are EX-920, EX-211 and EX-121 prepared by Nagase ChemteX Corporation, wherein the epoxy equivalent of EX-920 is 178g / equivalent, the epoxy equivalent of EX-211 is 138g / equivalent, and the epoxy equivalent of EX-121 is 187g / equivalent.

[0012] In order to further improve the dispersibility of titanium dioxide in the titanium dioxide dispersion and enhance the anti-settling effect of the titanium dioxide dispersion, in some embodiments, the epoxy equivalent of the epoxy group in the bridging agent is 138-187 g / equivalent.

[0013] In some of the embodiments, titanium dioxide, moisturizing agent, auxiliary agent and bridging agent are mixed under stirring, the stirring speed is 2000 rpm-4000 rpm, and the stirring time is 2h-5h.

[0014] In some of the embodiments, the first dispersant is added to the mixed solution under stirring, the stirring speed is 2000 rpm-4000 rpm, and the stirring time is 30 min-60 min.

[0015] In order to further enhance the anti-settling effect of the titanium dioxide dispersion and the whiteness of the formed coating, in some embodiments, after the mixed liquid and the first dispersant are mixed, the step of grinding the dispersant formed by the mixed liquid and the first dispersant is also included, the grinding speed is 2300-3000rpm, the grinding time is 3-5h, and after grinding, the particle size of titanium dioxide in the titanium dioxide color paste is 100-200nm.

[0016] In some embodiments, the titanium dioxide content in the titanium dioxide paste is 50%-60%, the first dispersant content is 10%-15%, the moisturizer content is 10%-20%, the auxiliary content is 0.5%-1%, and the bridging agent content is 0.5%-1%. Within the above content ranges of each component, the architectural white paint can provide sufficient whiteness and avoid the precipitation of titanium dioxide.

[0017] In some embodiments, the titanium dioxide surface modified with alumina includes TIPAQUE PF-726 prepared by Ishihara Industry Co., Ltd., JR-806 prepared by Tili Power Co., Ltd., TiPure 200 prepared by EI DuPont de Nemours Co., Ltd. TM R700, R900, TiPure TM R796、TiPure TM R706 and TiPure TM R906 and Chemours At least one of R960.

[0018] Furthermore, in the embodiment of the present invention, the first dispersant includes at least one of BYK2010, TEGO Dispers 752W, Dispersogen PL30, and OROTAN 1618.

[0019] Alcohols and ethers both have a moisturizing effect, which can prevent the color paste or ink from being too dry and solidified during placement. Ethers are more volatile than alcohols, so ether solvents can be used to adjust the range of dryness and moisturizing properties, which can not only moisturize the ink, but also make the ink dry quickly during printing to avoid ink flow. In some embodiments, the moisturizing agent includes at least one of glycerin, ethylene glycol, propylene glycol, glycerol, 1,6-hexanediol, and propylene glycol monobutyl ether.

[0020] In order to avoid excessive foam or poor wettability during the printing process causing inkjet hole breakage and affecting the quality of the printed pattern, in some embodiments, the auxiliary agent includes at least one of sodium dodecylbenzene sulfonate, organic silicone, and acetylene glycol surfactants.

[0021] The architectural white paint further comprises polyurethane, a second dispersant, a thickener, a surfactant and a wetting agent.

[0022] In terms of mass percentage, in the white architectural paint, the content of titanium dioxide color paste is 20%-30%, the content of polyurethane is 10%-25%, the content of the second dispersant is 0.1%-0.5%, the content of the thickener is 1%-5%, and the content of the wetting agent is 0.1%-0.5%.

[0023] Wherein, the thickener includes sodium alginate; the surfactant includes acetylene glycol surfactant; and the wetting agent includes siloxane compound.

[0024] Furthermore, in the embodiment of the present invention, the second dispersant includes at least one of BYK2010, TEGO Dispers 752W, Dispersogen PL30, and OROTAN 1618.

[0025] The white paint for construction also includes a pH regulator and a fungicide. The pH regulator is triethanolamine, and the fungicide includes at least one of isothiazolinone and 1,2-phenylisothiazoline-3-one.

[0026] The technical solution of the present invention has the following advantages:

[0027] The present invention provides a white paint for construction, including titanium dioxide color paste, and the preparation method of the titanium dioxide color paste includes the following steps: mixing titanium dioxide, a moisturizing agent, an auxiliary agent and a bridging agent, and heat treating to obtain a mixed solution, wherein the bridging agent includes a compound containing an epoxy group, and the epoxy equivalent of the epoxy group is 130g / equivalent to 200g / equivalent, and the temperature of the heat treatment is 60°C to 80°C; adding a first dispersant to the mixed solution, mixing, and obtaining a white paint, wherein the first dispersant includes a polymer containing an affinity group. Since there are positive and negative charges on the surface of titanium dioxide, they will attract each other due to electrostatic effects, resulting in the aggregation of titanium dioxide, which is more likely to cause sedimentation, and even cause the printing nozzle to be blocked in severe cases. The present invention connects the bridging agent and titanium dioxide together through heat treatment, and further, in order to enhance the water solubility of the cross-linked titanium dioxide, a dispersant is added, and the lipophilic end of the dispersant reacts with the bridging agent, and the hydrophilic end is soluble in the aqueous solution at the outer end, which helps to improve the stability of the water-based pigment ink. At the same time, after the bridging agent and the dispersant are connected, the steric hindrance of the titanium dioxide particles is increased, thereby avoiding the phenomenon of aggregation due to the increase of the surface energy of the titanium dioxide.

[0028] At the same time, alumina is used to modify titanium dioxide. First, the surface energy of alumina is lower than that of titanium dioxide. After modification, titanium dioxide is less likely to aggregate. Second, alumina has higher ability to reflect and refract light, which helps to improve the overall whiteness of white architectural paint. Third, the chemical inertness of alumina helps to improve the weather resistance, acid and alkali resistance and other properties of white architectural paint.

[0029] Furthermore, since epoxy resin has excellent adhesion to alumina at room temperature, and under the reaction conditions of 60℃-80℃, epoxy resin is used as a bridging agent. After the epoxy resin is ring-opened, it will chemically bond with the alumina on the surface of titanium dioxide, thereby successfully connecting the epoxy resin chain to the surface of titanium dioxide. The long chain of epoxy resin forms a steric hindrance, so titanium dioxide is not easy to gather together and enhance the anti-sedimentation property, so that the titanium dioxide combined with epoxy resin has better whiteness and opacity. Epoxy resin with an epoxy equivalent of 130-200g / equivalent can react with alumina at a lower temperature. If the epoxy equivalent is too low, it cannot fully encapsulate titanium dioxide. If the epoxy equivalent is too high, it will affect the flexibility of the ink.

[0030] Furthermore, the embodiment of the present invention can interact with the other end of the epoxy resin by adding a dispersant having an affinity group polymer, which can not only enhance the water solubility of the titanium dioxide color paste, but also increase the steric hindrance and play a dispersing role. DETAILED DESCRIPTION

[0031] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0032] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0033] The titanium dioxide in the embodiment of the present invention is selected from TIPAQUE PF-726 prepared by Ishihara Industry Co., Ltd., JR-806 prepared by Tili Power Co., Ltd., TiPure 100 prepared by EI DuPont de Nemours Co., Ltd. TM R700、TiPure TM R900、TiPure TM R796、TiPure TM R706 and TiPure TM R906 and Chemours R960.

[0034] The bridging agent is selected from at least one of propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether and 2-ethylhexyl glycidyl ether. The specific product models are EX-920 (propylene glycol diglycidyl ether), EX-211 (pentanediol diglycidyl ether), EX-121 (2-ethylhexyl glycidyl ether), EX-201 (resorcinol diglycidyl ether) and EX-146 (tert-butylphenyl glycidyl ether) prepared by Nagase ChemteX Corporation, wherein the epoxy equivalent of EX-920 is 178 g / equivalent, the epoxy equivalent of EX-211 is 138 g / equivalent, the epoxy equivalent of EX-121 is 187 g / equivalent, the epoxy equivalent of EX-201 is 117 g / equivalent, and the epoxy equivalent of EX-146 is 225 g / equivalent.

[0035] The first dispersant and the second dispersant are selected from BYK2010, TEGO Dispers 752W, Dispersogen PL30 and OROTAN 1618.

[0036] Example 1

[0037] This embodiment provides a method for preparing a white paint for construction, and the specific steps and methods are as follows:

[0038] (1) Weigh titanium dioxide (produced by EI DuPont de Nemours and marketed under the trade name TiPure) according to the following mass percentages: TM R906) 50.0%, sodium dodecylbenzene sulfonate 0.6%, 1,6-hexanediol 5.0%, propylene glycol 5.0%, epoxy resin (Nagase ChemteX Corporation prepared under the trade name EX-920, epoxy equivalent of 138g / equivalent) 0.5%, deionized water 28.9% and the first dispersant under the trade name BYK2010 10%, titanium dioxide, sodium dodecylbenzene sulfonate, 1,6-hexanediol, propylene glycol and EX-920 are put into a stirring tank in sequence, the stirring speed is set to 3000rpm, and stirring is carried out for 4 hours; after the solution is mixed evenly, the reaction temperature is controlled at 60℃ by circulating hot water at 60℃ (the hot water is circulated through the outer wall of the stirring tank to control the reaction temperature in the stirring tank), and the reaction time is 1 hour; finally, the temperature of the mixed solution is naturally reduced to room temperature, the first dispersant under the trade name BYK2010 is added thereto, and after stirring at a speed of 3000rpm for 1 hour, a titanium dioxide dispersant is formed.

[0039] (2) The titanium dioxide dispersant prepared in step (1) was added to a grinding machine containing zirconium oxide with a filling rate of 75 wt % and 0.3 mm, and ground at 2500 rpm for 4 h. The average particle size of the ground product was measured to be 150 nm, thereby preparing a titanium dioxide color paste.

[0040] (3) According to the following mass percentages, 20% of the titanium dioxide color paste prepared in step (2), 25% of the water-based polyurethane emulsion (purchased from Shenzhen Yoshida, water-based polyurethane emulsion 1526), ​​15% of ethylene glycol, 5% of propylene glycol, 0.5% of a wetting agent (TEGO260), 0.2% of a surfactant (Surfynol 465), 0.1% of a second dispersant (BYK2010), 5% of sodium alginate, 0.1% of triethanolamine, 0.1% of isothiazolinone, and 29% of deionized water were weighed, and the above materials were added into a stirring tank in sequence. The stirring speed was set to 2000 rpm and stirred for 4 hours to obtain a white paint for architecture.

[0041] The obtained white paint for construction was filtered using a 0.45 um filter membrane.

[0042] Example 2

[0043] This embodiment provides a method for preparing a white paint for construction. The specific steps and parameters are the same as those in Example 1, except that an epoxy resin of equal mass (trade name EX-920 produced by Nagase ChemteX Corporation, epoxy equivalent weight 178 g / equivalent) is used to replace step (1) EX-211.

[0044] Example 3

[0045] This embodiment provides a method for preparing a white paint for construction. The specific steps and parameters are the same as those in Example 1, except that an epoxy resin of equal mass (trade name EX-121 produced by Nagase ChemteX Corporation, epoxy equivalent weight 187 g / equivalent) is used to replace step (1) EX-211.

[0046] Example 4

[0047] This embodiment provides a method for preparing a white paint for construction. The specific steps and parameters are the same as those in Example 1, except that an equal mass of titanium dioxide (TIPAQUE PF-726, a product manufactured by Ishihara Sangyo Co., Ltd.) is used to replace the titanium dioxide (TiPure, a product manufactured by EI DuPont de Nemours, Ltd., in step (1). TM R906 Titanium Dioxide.

[0048] Example 5

[0049] This embodiment provides a method for preparing a white paint for construction. The specific steps and parameters are the same as those in Example 1, except that an equal mass of titanium dioxide (JR-806 manufactured by Tili Power Co., Ltd.) is used to replace TiPure manufactured by EI DuPont de Nemours in step (1). TM R906 Titanium Dioxide.

[0050] Example 6

[0051] This embodiment provides a method for preparing a white paint for construction. The specific steps and parameters are the same as those in Example 1, except that an equal mass of titanium dioxide (trade name prepared by Chemours) is used. R960) replaces the EI DuPont de Nemours prepared in step (1) and the trade name is TiPure TM R906 Titanium Dioxide.

[0052] Example 7

[0053] This embodiment provides a method for preparing white paint for construction. The specific steps and parameters are the same as those in Embodiment 1, except that the heat treatment temperature in step (1) is set to 80°C.

[0054] Example 8

[0055] This embodiment provides a method for preparing a white paint for construction, and the specific steps and methods are as follows:

[0056] (1) Titanium dioxide (produced by EI DuPont de Nemours under the trade name TiPure TM R700) 60.0%, Surfynol 465 1.0%, glycerol 8.0%, ethylene glycol 8.0%, epoxy resin (NagaseChemteX Corporation prepared under the trade name EX-920, epoxy equivalent of 138g / equivalent) 1.0%, deionized water 7% and the first dispersant under the trade name TEGO Dispers 752W 15%, titanium dioxide, Surfynol 465, glycerol, ethylene glycol and EX-920 are put into a stirring tank in sequence, the stirring speed is set to 2000rpm, and stirring is carried out for 5 hours; after the solution is mixed evenly, the reaction temperature is controlled at 60°C using 60°C circulating hot water (the hot water is circulated through the outer wall of the stirring tank to control the reaction temperature in the stirring tank), and the reaction time is 1 hour; finally, the temperature of the mixed solution is naturally reduced to room temperature, the first dispersant under the trade name TEGO Dispers 752W is added thereto, and the titanium dioxide dispersant is formed after stirring at a speed of 4000rpm for 30min.

[0057] (2) The titanium dioxide dispersant prepared in step (1) was added to a grinding machine containing zirconium oxide with a filling rate of 75 wt % and a diameter of 0.3 mm. The grinding was performed at 2300 rpm for 5 h. The average particle size of the ground product was measured to be 200 nm, thereby preparing a titanium dioxide color paste.

[0058] (3) According to the following mass percentages, 30% of the titanium dioxide color paste prepared in step (2), 10% of the aqueous polyurethane emulsion (purchased from Shenzhen Yoshida, aqueous polyurethane emulsion 1526), ​​15% of ethylene glycol, 5% of propylene glycol, 0.1% of a wetting agent (TEGO260), 0.2% of a surfactant (Surfynol 465), 0.5% of a second dispersant (BYK2010), 1% of sodium alginate, 0.1% of triethanolamine, 0.1% of isothiazolinone, and 38% of deionized water were weighed, and the above materials were added into a stirring tank in sequence. The stirring speed was set to 2000 rpm and stirred for 4 hours to obtain a white paint for architecture.

[0059] The obtained white paint for construction was filtered using a 0.45 um filter membrane.

[0060] Example 9

[0061] This embodiment provides a method for preparing a white paint for construction, and the specific steps and methods are as follows:

[0062] (1) Weigh titanium dioxide (produced by EI DuPont de Nemours and marketed under the trade name TiPure) according to the following mass percentages: TM R900) 50.0%, sodium dodecylbenzene sulfonate 0.5%, propylene glycol monobutyl ether 10.0%, glycerol 10.0%, epoxy resin (Nagase ChemteX Corporation prepared under the trade name EX-920, epoxy equivalent of 138g / equivalent) 0.5%, deionized water 19% and the first dispersant under the trade name Dispersogen PL30 10%, titanium dioxide, sodium dodecylbenzene sulfonate, 1,6-hexanediol, propylene glycol and EX-920 are put into a stirring tank in sequence, the stirring speed is set to 4000rpm, and stirring is carried out for 2 hours; after the solution is mixed evenly, the reaction temperature is controlled at 60°C by circulating hot water at 60°C (the hot water is circulated through the outer wall of the stirring tank to control the reaction temperature in the stirring tank), and the reaction time is 2 hours; finally, the temperature of the mixed solution is naturally reduced to room temperature, and the first dispersant under the trade name Dispersogen PL30 is added thereto, and after stirring at a speed of 2000rpm for 1 hour, a titanium dioxide dispersant is formed.

[0063] (2) The titanium dioxide dispersant prepared in step (1) was added to a grinding machine containing zirconium oxide with a filling rate of 75 wt% and a diameter of 0.3 mm. The grinding was carried out at 3000 rpm for 3 h. The average particle size of the ground product was measured to be 200 nm, thereby preparing a titanium dioxide color paste.

[0064] (3) According to the following mass percentages, 20% of the titanium dioxide color paste prepared in step (2), 25% of the water-based polyurethane emulsion (purchased from Shenzhen Yoshida, water-based polyurethane emulsion 1526), ​​15% of ethylene glycol, 5% of propylene glycol, 0.5% of a wetting agent (TEGO260), 0.2% of a surfactant (Surfynol 465), 0.1% of a second dispersant (OROTAN 1618), 5% of sodium alginate, 0.1% of triethanolamine, 0.1% of 1,2-phenylisothiazoline-3-one, and 29% of deionized water were weighed, and the above materials were added into a stirring tank in sequence. The stirring speed was set to 2000 rpm and stirred for 4 hours to obtain a white paint for construction.

[0065] The obtained white paint for construction was filtered using a 0.45 um filter membrane.

[0066] Example 10

[0067] This embodiment provides a method for preparing a white paint for construction, and the specific steps and methods are as follows:

[0068] (1) Weigh titanium dioxide (produced by EI DuPont de Nemours and marketed under the trade name TiPure) according to the following mass percentages: TM R796) 50.0%, sodium dodecylbenzene sulfonate 0.6%, 1,6-hexanediol 5.0%, propylene glycol 5.0%, epoxy resin (Nagase ChemteX Corporation prepared under the trade name EX-920, epoxy equivalent of 138g / equivalent) 0.5%, deionized water 28.9% and the first dispersant under the trade name OROTAN1618 10%, titanium dioxide, sodium dodecylbenzene sulfonate, 1,6-hexanediol, propylene glycol and EX-920 are put into a stirring tank in sequence, the stirring speed is set to 3000rpm, and stirring is carried out for 4 hours; after the solution is evenly mixed, the reaction temperature is controlled at 60℃ by using 60℃ circulating hot water (the hot water is circulated through the outer wall of the stirring tank to control the reaction temperature in the stirring tank), and the reaction time is 1 hour; finally, the temperature of the mixed solution is naturally reduced to room temperature, and the first dispersant under the trade name OROTAN 1618 is added thereto, and after stirring at a speed of 3000rpm for 1 hour, a titanium dioxide dispersant is formed.

[0069] (2) The titanium dioxide dispersant prepared in step (1) was added to a grinding machine containing zirconium oxide with a filling rate of 75 wt % and 0.3 mm, and ground at 2500 rpm for 4 h. The average particle size of the ground product was measured to be 150 nm, thereby preparing a titanium dioxide color paste.

[0070] (3) According to the following mass percentages, 20% of the titanium dioxide color paste prepared in step (2), 25% of the aqueous polyurethane emulsion (purchased from Shenzhen Yoshida, aqueous polyurethane emulsion 1526), ​​15% of ethylene glycol, 5% of propylene glycol, 0.5% of a wetting agent (TEGO260), 0.2% of a surfactant (Surfynol 465), 0.1% of a second dispersant (TEGO Dispers 752W), 5% of sodium alginate, 0.1% of triethanolamine, 0.1% of isothiazolinone, and 29% of deionized water were weighed, and the above materials were added into a stirring tank in sequence. The stirring speed was set to 2000 rpm and stirred for 4 hours to obtain a white paint for architecture.

[0071] The obtained white paint for construction was filtered using a 0.45 um filter membrane.

[0072] Comparative Example 1

[0073] This comparative example provides a method for preparing a white paint for construction. The specific steps and methods are the same as those in Example 1, except that an equal amount of glutaraldehyde is used to replace the bridging agent in step (1).

[0074] Comparative Example 2

[0075] This comparative example provides a method for preparing a white paint for construction. The specific steps and methods are the same as those in Example 1, except that an equal mass of EX-201 is used to replace the bridging agent in step (1), and its epoxy equivalent is 117 g / equivalent.

[0076] Comparative Example 3

[0077] This comparative example provides a method for preparing a white paint for construction. The specific steps and methods are the same as those in Example 1, except that an equal mass of EX-146 is used to replace the bridging agent in step (1), and the epoxy equivalent thereof is 225 g / equivalent.

[0078] Comparative Example 4

[0079] This comparative example provides a method for preparing a white paint for construction. The specific steps and methods are the same as those in Example 1, except that an equal amount of propylene glycol is used to replace the dispersant in step (1).

[0080] Comparative Example 5

[0081] This comparative example provides a method for preparing a white paint for construction. The specific steps and methods are the same as those in Example 1, except that the heat treatment temperature is 50°C.

[0082] Comparative Example 6

[0083] This comparative example provides a method for preparing a white paint for construction. The specific steps and methods are the same as those in Example 1, except that the heat treatment temperature is 90°C.

[0084] Comparative Example 7

[0085] This comparative example provides a method for preparing a white paint for construction. The specific steps and methods are the same as those in Example 1, except that: (1) titanium dioxide (prepared by EI DuPont de Nemours and known as TiPure TM R906) 50.0%, sodium dodecylbenzene sulfonate 0.6%, 1,6-hexanediol 5.0%, propylene glycol 5.0%, epoxy resin (Nagase ChemteX Corporation's trade name is EX-920, epoxy equivalent is 138g / equivalent) 0.5%, first dispersant (BYK2010) 10%, titanium dioxide, sodium dodecylbenzene sulfonate, 1,6-hexanediol, propylene glycol and the first dispersant are put into a stirring tank in sequence, the stirring speed is set to 3000rpm, and stirring is carried out for 4 hours; after the solution is mixed evenly, 60°C circulating hot water is introduced (the hot water circulates through the outer wall of the stirring tank to control the reaction temperature in the stirring tank), the reaction temperature is controlled at 60°C, and the reaction time is 1 hour; finally, the temperature of the mixed solution is naturally reduced to room temperature, and after stirring at a speed of 3000rpm for 1 hour, a titanium dioxide dispersant is formed.

[0086] The remaining steps are the same as those in Example 1.

[0087] Comparative Example 8

[0088] This comparative example provides a method for preparing a white paint for construction. The specific steps and methods are the same as those in Example 1, except that titanium dioxide that has not been modified with alumina (Brofos-TiO2-J150 prepared by Brofos Nanotechnology (Ningbo) Co., Ltd.) is used to replace the titanium dioxide in step (1).

[0089] Experimental example

[0090] 1. Anti-settling test

[0091] The specific method of the anti-sedimentation test is as follows: the titanium dioxide color paste prepared in step (1) of Examples 1-7 and Comparative Examples 1-8 is placed in a sealed container at room temperature. Specifically, 30 mL of the prepared titanium dioxide color paste is weighed and poured into a 50 mL test bottle, the bottle cap is tightened, and the state is observed at 3 days, 7 days, 30 days, 60 days, and 90 days, respectively.

[0092] The evaluation criteria for anti-settling test are as follows:

[0093] A: No obvious particle precipitation, flocculation, etc.

[0094] B: Millimeter-sized particles flocculate and precipitate, and can be evened out by shaking;

[0095] C: Slight precipitation occurs, which can be dispersed evenly by shaking;

[0096] D: Obvious particle precipitation and stratification occur, and shaking cannot achieve uniform dispersion.

[0097] The testers for the anti-settling test were ten volunteers.

[0098] The test results are shown in Table 1.

[0099] Table 1 Anti-settling test results

[0100]

[0101]

[0102] According to Table 1, compared with Comparative Examples 1-8, the titanium dioxide dispersion prepared in the embodiment of the present invention has good anti-settling effect and a longer retention time. Specifically, Comparative Example 1 uses glutaraldehyde without epoxy groups as a bridging agent, Comparative Examples 2-3 use materials with epoxy equivalents of 117 g / equivalent and 225 g / equivalent as bridging agents, Comparative Example 4 uses propylene glycol as a dispersant, and Comparative Examples 5-6 use 50° C. and 80° C. as heat treatment temperatures to form a titanium dioxide dispersion. When the storage time is 3 days, the anti-settling effect is good, but as the storage time increases, the anti-settling effect of the titanium dioxide dispersion becomes worse, while Comparative Example 7 forms a titanium dioxide dispersion by mixing the first dispersant and other materials at the same time. The titanium dioxide dispersion formed by the modified titanium dioxide raw material is used in the liquid and comparative example 8. When the storage time is three days, the anti-sedimentation effect is very poor, which further illustrates the preparation method of the embodiment of the present invention. The bridging agent and titanium dioxide can be connected together by heat treatment. In order to enhance the water solubility of the cross-linked titanium dioxide, a dispersant is added, wherein the lipophilic end of the dispersant reacts with the bridging agent, and the hydrophilic end is soluble in the aqueous solution at the outer end, which helps to improve the stability of the aqueous pigment ink. By adding a dispersant having an affinity group polymer, it can interact with the other end of the epoxy resin, which can not only enhance the water solubility of the titanium dioxide color paste, but also increase the steric hindrance and play a dispersing role.

[0103] 2. Dispersion and whiteness test

[0104] The white architectural coatings prepared in Examples 1-7 and Comparative Examples 1-8 were respectively measured to print pure color blocks, i.e., solid pure white circular patterns, on silicate rock boards after standing for 0 days, 7 days, 14 days, and 21 days after preparation.

[0105] The L value of the pattern is tested using a colorimeter. The L value represents the brightness of the pattern. The higher the L value, the higher the brightness. The higher the brightness, the better the dispersion of titanium dioxide in the ink. The test results are shown in Table 2 below.

[0106] Table 2 Dispersion test results

[0107]

[0108] According to Table 2, compared with Comparative Examples 1-8, the dispersion of titanium dioxide in the architectural white paint prepared in the embodiment of the present invention is better and maintained for a longer time.

[0109] The whiteness test method is to test according to the method specified in Appendix B of the chemical industry standard "HG / T 4786-2014 Latex Color Paste". The relative tinting strength of the prepared titanium dioxide white paste, the relative tinting strength indicates the whiteness of the titanium dioxide paste, the higher the relative tinting strength, the better the whiteness of the titanium dioxide paste. The test results are shown in Table 3 below.

[0110] Table 3 Whiteness test results

[0111] Relative tinting strength Relative tinting strength Example 1 93 Comparative Example 2 78 Example 2 91 Comparative Example 3 76 Example 3 92 Comparative Example 4 72 Example 4 93 Comparative Example 5 75 Example 5 92 Comparative Example 6 73 Example 6 91 Comparative Example 7 71 Example 7 91 Comparative Example 8 73 Comparative Example 1 75

[0112] It can be seen from Table 3 that compared with Comparative Examples 1-8, the whiteness of the architectural white paint prepared in the embodiments of the present invention is much higher than that of the comparative examples.

[0113] Specifically, comparative example 1 uses glutaraldehyde without epoxy group as a bridging agent, comparative examples 2-3 use materials with epoxy equivalents of 117g / equivalent and 225g / equivalent as bridging agents, comparative example 4 uses propylene glycol as a dispersant, comparative examples 5-6 use 50°C and 80°C as heat treatment temperatures to form a titanium dioxide dispersion, comparative example 7 is formed by mixing the dispersant and other materials at the same time, and comparative example 8 uses modified titanium dioxide as a raw material to form a titanium dioxide dispersion. The dispersion degree of the titanium dioxide dispersion is much lower than that of the titanium dioxide dispersion formed in the examples of the present application, which further proves that the architectural white paint prepared in the examples of the present invention not only has better dispersibility but also has better whiteness and opacity.

[0114] 3. Weather resistance test

[0115] The white architectural coatings prepared in Examples 1-7 and Comparative Examples 1-8 were printed on silicate rock panels to obtain samples. The samples were tested for acid resistance, alkali resistance, aging resistance, light resistance and adhesion. The test results are shown in Table 1.

[0116] Among them, the acid resistance test method is carried out in accordance with the provisions of HG / T4343-20125.4.11;

[0117] The alkali resistance test method is carried out in accordance with the provisions of GB / T9265;

[0118] Aging resistance is carried out in accordance with the provisions of JC / T287-20136.4.13;

[0119] The adhesion test method is carried out in accordance with the provisions of GB / T9286;

[0120] Weathering test The light resistance test was carried out in accordance with the requirements of 5.9 of the inkjet printing ink industry standard QB / T2730.1-2005.

[0121] Table 4 Weathering resistance of white paint for building

[0122]

[0123]

[0124] According to Table 4, compared with Comparative Examples 1-8, the white paint for construction prepared in the embodiment of the present invention has good weather resistance. Specifically, whether it is acid resistance, alkali resistance, aging resistance, light resistance or adhesion test, the weather resistance of the white paint for construction prepared in the embodiment is better than that of Comparative Examples 1-8.

[0125] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A white paint for construction, characterized in that: The invention comprises titanium dioxide color paste, and the preparation method of the titanium dioxide color paste comprises the following steps: Titanium dioxide, moisturizing agent, auxiliary agent and bridging agent are mixed and heat treated to obtain a mixed solution. The titanium dioxide comprises titanium dioxide surface-modified with aluminum oxide, The bridging agent comprises a compound containing an epoxy group, wherein the epoxy equivalent of the epoxy group is 130 g / equivalent to 200 g / equivalent, The temperature of the heat treatment is 60°C-80°C; A first dispersant is added to the mixed solution and mixed to obtain a white coating, wherein the first dispersant includes a polymer containing an affinity group.

2. The architectural white paint according to claim 1, characterized in that: The bridging agent comprises at least one of propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether and 2-ethylhexyl glycidyl ether; and / or, The heat treatment time is 1h-2h; and / or, The epoxy equivalent of the epoxy group in the bridging agent is 138 g / equivalent to 187 g / equivalent.

3. The architectural white paint according to claim 2, characterized in that: Mix titanium dioxide, moisturizing agent, auxiliary agent and bridging agent under stirring, wherein the stirring speed is 2000rpm-4000rpm and the stirring time is 2h-5h; and / or, Under stirring, adding the first dispersant to the mixed solution, the stirring speed is 2000rpm-4000rpm, and the stirring time is 30min-60min; and / or, After the mixed liquid and the first dispersant are mixed, the method further includes grinding the dispersant formed by mixing the mixed liquid and the first dispersant. The grinding speed is 2300rpm-3000rpm, the grinding time is 3h-5h, and after grinding, the particle size of titanium dioxide in the titanium dioxide color paste is 100nm-200nm.

4. The architectural white paint according to claim 3, characterized in that: In terms of mass percentage, the titanium dioxide content in the titanium dioxide color paste is 50%-60%, the first dispersant content is 10%-15%, the moisturizer content is 10%-20%, the auxiliary agent content is 0.5%-1%, the bridging agent content is 0.5%-1%, and the balance is water.

5. The architectural white paint according to claim 4, characterized in that: The trade names of the titanium dioxide surface modified with alumina include TIPAQUE PF-726, JR-806, TiPure TM R700、TiPure TM R900、TiPure TM R796、TiPure TM R706、TiPure TM R906 and At least one of R960; and / or, The trade name of the first dispersant includes at least one of BYK2010, TEGO Dispers 752W, Dispersogen PL30, and OROTAN 1618.

6. The architectural white paint according to claim 1, characterized in that: The moisturizing agent comprises at least one of an alcohol or an ether material; and / or, The auxiliary agent includes at least one of sodium dodecylbenzene sulfonate, organic siloxanes and acetylene glycol surfactants.

7. The architectural white paint according to claim 6, characterized in that: The moisturizing agent includes at least one of glycerin, ethylene glycol, propylene glycol, glycerol, 1,6-hexanediol, and propylene glycol monobutyl ether; and / or, The architectural white paint further comprises polyurethane, a second dispersant, a thickener, a surfactant and a wetting agent.

8. The architectural white paint according to claim 7, characterized in that: In terms of mass percentage, in the white architectural paint, the content of titanium dioxide color paste is 20%-30%, the content of polyurethane is 10%-25%, the content of the second dispersant is 0.1%-0.5%, the content of the thickener is 1%-5%, and the content of the wetting agent is 0.1%-0.5%.

9. The architectural white paint according to claim 8, characterized in that: The thickener comprises sodium alginate; and / or, The surfactant comprises an acetylenic diol surfactant; and / or, The wetting agent comprises a silicone compound; and / or, The second dispersant includes at least one of BYK2010, TEGO Dispers 752W, Dispersogen PL30, and OROTAN 1618.

10. The architectural white paint according to claim 9, characterized in that: The white paint for construction also includes a pH regulator and a bactericide. The pH adjuster includes triethanolamine, The bactericide includes at least one of isothiazolinone and 1,2-phenylisothiazoline-3-one.

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