Anti-shadow building coating and preparation method thereof

Abstract

The invention relates to an anti-shadow building coating and a preparation method thereof. The preparation method comprises the following steps: mixing silicon dioxide microspheres, a waterborne polyurethane resin emulsion, a waterborne hydroxy acrylic emulsion, colloidal silicon dioxide and water, then adding a curing agent, stirring and dispersing uniformly, then adding a titanic acid aqueous solution, and heating for hydrothermal treatment to obtain silicon dioxide microsphere slurry coated with a titanium coating; mixing the slurry with a waterborne polyurethane resin emulsion, a waterborne hydroxyl acrylic emulsion, colloidal silicon dioxide and water, then adding a curing agent, stirring and dispersing uniformly, then adding an orthosilicic acid aqueous solution, and reacting to obtain a composite slurry; and adding the acrylate polymer dispersant emulsion, the polyurethane modified acrylic resin and the water, and uniformly dispersing to obtain the coating. The building coating can greatly reduce the shadow problem and has a good application prospect.

Description

Technical Field

[0001] The invention relates to the field of coatings, in particular to an anti-shadow architectural coating and a preparation method thereof. Background Art

[0002] With the development of social economy, people's living standards are getting higher and higher, people's awareness of healthy living is improving, and increasingly stringent environmental protection regulations have put forward higher and higher requirements for the development of coatings, making the application of traditional coatings more and more restricted, making modern coatings develop in the direction of high performance, high efficiency, high environmental protection and high decorativeness.

[0003] The current architectural coatings have a serious shadow problem during the construction process, which affects the aesthetics of the exterior wall decoration coatings. The shadow problem of coatings is mainly caused by the following aspects: (1) Coating shadows caused by uneven lighting are most likely to occur in single-color coatings, especially dark coatings; (2) Coating shadows caused by uneven construction are most likely to occur in light-colored coatings; (3) Coating shadows caused by uneven base layers will cyclically appear or disappear with the change of coating temperature, that is, the shadow phenomenon caused by the coating cooling down. Summary of the invention

[0004] The purpose of the present invention is to provide a shadow-proof architectural coating and a preparation method thereof in order to overcome the defects of the above-mentioned prior art. The architectural coating of the present invention selects a slurry with a high refractive index, and the selected pigment and filler particle size is relatively coarse. The coating has a short-term energy storage function, releases heat at low temperatures, and absorbs heat at high temperatures, thereby adjusting the temperature change between the coating and the base layer to be consistent, and reducing the uneven heat absorption or heat release caused by the uneven base material.

[0005] The present invention solves the above technical problems through the following technical solutions: A method for preparing an anti-shadow architectural coating comprises the following steps: (1) mixing silica microspheres, aqueous polyurethane resin emulsion, aqueous hydroxy acrylic emulsion, colloidal silica, and water, adding a curing agent, stirring and dispersing the mixture evenly, adding a titanic acid aqueous solution, and heating the mixture for hydrothermal treatment to obtain a silica microsphere slurry coated with a titanium coating; (2) mixing the slurry obtained in step (1) with an aqueous polyurethane resin emulsion, an aqueous hydroxy acrylic emulsion, colloidal silica, and water, adding a curing agent, stirring and dispersing the mixture evenly, and then adding an aqueous solution of orthosilicic acid to react to obtain a composite slurry; (3) After adding acrylic polymer dispersant emulsion, polyurethane modified acrylic resin and water, the mixture is evenly dispersed. The acrylic polymer dispersant emulsion is prepared by the following method: in a solvent, methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate are polymerized under the action of an initiator and a surfactant to obtain an acrylic polymer dispersant emulsion.

[0006] Preferably, the titanic acid aqueous solution is prepared by the following steps: uniformly mixing titanium tetrachloride aqueous solution and ammonia water to obtain a mixed solution, then adding hydrogen peroxide and water, and stirring to react to obtain the titanic acid aqueous solution.

[0007] The pH value of the mixed solution is preferably 9-10.

[0008] The stirring reaction temperature is preferably 80-90° C., and the stirring reaction time is preferably 1-2 hours.

[0009] The temperature of the hydrothermal treatment is preferably 120-140° C., and the time of the hydrothermal treatment is preferably 1-2 hours.

[0010] In step (1), the particle size of the silica microspheres is preferably 100-120 microns.

[0011] In step (1), the aqueous polyurethane resin emulsion is preferably an aqueous polyurethane resin emulsion with a brand number of 1099R produced by Jining Fangyu Chemical Co., Ltd.

[0012] In step (1), the aqueous hydroxylated acrylic emulsion is preferably an aqueous hydroxylated acrylic emulsion with a brand name of CX-822 produced by Jining Fangyu Chemical Co., Ltd.

[0013] In step (1), the curing agent is preferably Evonik B1530 curing agent.

[0014] In step (2), the aqueous polyurethane resin emulsion is preferably an aqueous polyurethane resin emulsion with a brand number of 1099R produced by Jining Fangyu Chemical Co., Ltd.

[0015] In step (2), the aqueous hydroxylated acrylic emulsion is preferably an aqueous hydroxylated acrylic emulsion with a brand name of CX-822 produced by Jining Fangyu Chemical Co., Ltd.

[0016] In step (2), the curing agent is preferably Evonik B1530 curing agent.

[0017] In step (3), the polyurethane modified acrylic resin is preferably prepared by the following method: mixing hydroxy acrylate and isocyanate and heating them to react to obtain a polyurethane prepolymer; adding an organic solvent and polymerizing the polyurethane prepolymer with methyl methacrylate to obtain the polyurethane modified acrylic resin.

[0018] In a preferred embodiment of the present invention, the architectural coating may further include various additives.

[0019] If an auxiliary agent is included, it is added in step (3).

[0020] The invention also provides a shadow-proof architectural coating prepared by the preparation method.

[0021] Compared with the prior art, the present invention has the following beneficial effects: the present invention adopts the method of coating the surface of silica microspheres with a titanium coating and then coating the surface of the silica microspheres with a silica coating, and the different monomers and multiple reactive functional groups of the aqueous polyurethane resin emulsion and the aqueous hydroxy acrylic emulsion have good reactivity with multiple reactive groups on the surface of the silica microspheres, and the obtained composite slurry has a high refractive index. The composite slurry is applied to architectural coatings, which can greatly reduce the shadow problem of the coatings, and the prepared coating has a short-time energy storage function, releases heat at low temperatures, and absorbs heat at high temperatures, thereby adjusting the temperature changes between the coating and the base layer to be consistent, and reducing the uneven heat absorption or heat release caused by the uneven base material. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a photo of the exterior wall coating of Example 1 of the present invention Figure 2 This is a photo of the exterior wall coating of Example 2 of the present invention Figure 3 This is a photo of the coating in the prior art DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to specific embodiments.

[0024] In the following embodiments, the aqueous hydroxyl acrylic emulsion is the aqueous hydroxyl acrylic emulsion with the brand CX-822 produced by Jining Fangyu Chemical Co., Ltd.; the curing agent is Evonik B1530 curing agent; and the aqueous polyurethane resin emulsion is the aqueous polyurethane resin emulsion with the brand 1099R produced by Jining Fangyu Chemical Co., Ltd.

[0025] Unless otherwise specified, the following are parts by weight. Example

[0026] The anti-shadow architectural coating of this embodiment is prepared by the following method: (1) 3 parts of silica microspheres (D50 = 100 microns), 70 parts of aqueous polyurethane resin emulsion, 20 parts of aqueous hydroxy acrylic emulsion, 10 parts of colloidal silica, and 100 parts of water are mixed, and then 1 part of a curing agent is added, and after stirring and dispersing evenly, 2 parts of a titanic acid aqueous solution are added, and heated for hydrothermal treatment (120° C., 1 hour) to obtain a silica microsphere slurry coated with a titanium coating; wherein the titanic acid aqueous solution is prepared by the following steps: titanium tetrachloride aqueous solution and ammonia water are mixed evenly to obtain a mixed solution, the pH value is adjusted to 9, and then hydrogen peroxide and water are added, and the reaction is stirred at 80° C. for 1 hour to obtain a titanic acid aqueous solution; (2) 10 parts of the slurry obtained in step (1) were mixed with 70 parts of aqueous polyurethane resin emulsion, 20 parts of aqueous hydroxy acrylic emulsion, 10 parts of colloidal silica and 100 parts of water, and then 2 parts of curing agent were added. After stirring and dispersing evenly, 5 parts of orthosilicic acid aqueous solution were added, and the mixture was reacted at 110° C. to obtain a composite slurry; (3) After adding 10 parts of acrylic polymer dispersant emulsion, 50 parts of polyurethane modified acrylic resin and 100 parts of water, disperse them evenly; the acrylic polymer dispersant emulsion is prepared by the following method: in a solvent (deionized water), methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate are polymerized at 70°C under the action of an initiator (ammonium persulfate) and a surfactant (AEROSOL EF-810 of Solvay) to obtain an acrylic polymer dispersant emulsion; wherein the mass ratio of methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate is 2:1:1.

[0027] The polyurethane modified acrylic resin is prepared by the following method: hydroxy acrylate and isocyanate are mixed in a mass ratio of 1:1.2 and heated to react to obtain a polyurethane prepolymer; an organic solvent (propylene glycol ethyl ether) is added, and the polyurethane prepolymer and methyl methacrylate are polymerized for 3 hours under the initiation of ammonium persulfate; the isocyanate is diphenylmethane diisocyanate. Example

[0028] The anti-shadow architectural coating of this embodiment is prepared by the following method: (1) 5 parts of silica microspheres (D50 = 120 microns), 70 parts of aqueous polyurethane resin emulsion, 20 parts of aqueous hydroxy acrylic emulsion, 10 parts of colloidal silica, and 100 parts of water are mixed, and then 1 part of a curing agent is added, and after being stirred and dispersed evenly, 4 parts of a titanic acid aqueous solution are added, and heated for hydrothermal treatment (140° C., 2 hours) to obtain a silica microsphere slurry coated with a titanium coating; wherein the titanic acid aqueous solution is prepared by the following steps: titanium tetrachloride aqueous solution and ammonia water are mixed evenly to obtain a mixed solution, the pH value is adjusted to 10, and then hydrogen peroxide and water are added, and the reaction is stirred at 90° C. for 2 hours to obtain a titanic acid aqueous solution; (2) 15 parts of the slurry obtained in step (1) were mixed with 70 parts of aqueous polyurethane resin emulsion, 20 parts of aqueous hydroxy acrylic emulsion, 10 parts of colloidal silica and 100 parts of water, and then 3 parts of curing agent were added. After stirring and dispersing evenly, 7 parts of orthosilicic acid aqueous solution were added, and the mixture was reacted at 120° C. to obtain a composite slurry; (3) After adding 12 parts of acrylic polymer dispersant emulsion, 50 parts of polyurethane modified acrylic resin and 100 parts of water, disperse them evenly; the acrylic polymer dispersant emulsion is prepared by the following method: in a solvent (deionized water), methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate are polymerized at 80°C under the action of an initiator (ammonium persulfate) and a surfactant (AEROSOL EF-810 of Solvay) to obtain an acrylic polymer dispersant emulsion; wherein the mass ratio of methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate is 2:1:1.

[0029] The polyurethane modified acrylic resin is prepared by the following method: hydroxy acrylate and isocyanate are mixed in a mass ratio of 1:1.3 and heated to react to obtain a polyurethane prepolymer; an organic solvent (propylene glycol ethyl ether) is added, and the polyurethane prepolymer and methyl methacrylate are polymerized for 3 hours under the initiation of ammonium persulfate; the isocyanate is diphenylmethane diisocyanate. Example

[0030] The coating obtained in the above embodiment is applied to a substrate, and then dried and cured at high temperature to obtain a coating.

[0031] Coating testing standards: The storage stability test condition is baking in an oven at 42°C for 24 hours; the impact strength test is based on GB / T1732-1993; the coating appearance test is based on visual observation; the heat resistance test condition is baking in an oven at 350°C for 48 hours; the coating weather resistance test is based on GB / T14522-2008.

[0032] The coating performance test is shown in the following table.

[0033] .

[0034] Figure 1 This is a photo of the exterior wall coating of an embodiment of the present invention. Figure 2 This is a photo of the exterior wall coating of Example 2 of the present invention. Figure 3 Comparing the three pictures, it can be seen that the coating of the present invention has no shadow phenomenon, while the coating of the prior art produces shadows due to the influence of light, which seriously hinders the beauty and application prospects of the product.

[0035] It must be emphasized that the above detailed description is a specific description of a feasible embodiment of the present invention, but the embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the technical spirit of the present invention should be included in the patent scope of the present invention.

Claims

1. A method for preparing an anti-shadow architectural coating, comprising the following steps: (1) mixing silica microspheres, aqueous polyurethane resin emulsion, aqueous hydroxy acrylic emulsion, colloidal silica, and water, adding a curing agent, stirring and dispersing the mixture evenly, adding a titanic acid aqueous solution, and heating the mixture for hydrothermal treatment to obtain a silica microsphere slurry coated with a titanium coating; (2) mixing the slurry obtained in step (1) with an aqueous polyurethane resin emulsion, an aqueous hydroxy acrylic emulsion, colloidal silica, and water, adding a curing agent, stirring and dispersing the mixture evenly, and then adding an aqueous solution of orthosilicic acid to react to obtain a composite slurry; (3) After adding acrylic polymer dispersant emulsion, polyurethane modified acrylic resin and water, the mixture is evenly dispersed. The acrylic polymer dispersant emulsion is prepared by the following method: in a solvent, methyl methacrylate, hydroxyethyl methacrylate and 1,6-hexanediol dimethacrylate are polymerized under the action of an initiator and a surfactant to obtain an acrylic polymer dispersant emulsion.

2. The preparation method according to claim 1, characterized in that The titanic acid aqueous solution is prepared by the following steps: uniformly mixing titanium tetrachloride aqueous solution and ammonia water to obtain a mixed solution, then adding hydrogen peroxide and water, and stirring to react to obtain the titanic acid aqueous solution.

3. The preparation method according to claim 2, characterized in that: The pH value of the mixed solution is preferably 9-10; The stirring reaction temperature is preferably 80-90° C., and the stirring reaction time is preferably 1-2 hours.

4. The preparation method according to claim 1, characterized in that: The temperature of the hydrothermal treatment is 120-140° C., and the time of the hydrothermal treatment is 1-2 hours.

5. The preparation method according to claim 1, characterized in that: In step (1), the particle size of the silica microspheres is preferably 100-120 μm; the aqueous polyurethane resin emulsion is an aqueous polyurethane resin emulsion with a brand number of 1099R produced by Jining Fangyu Chemical Co., Ltd.; In step (1), the aqueous hydroxylated acrylic emulsion is an aqueous hydroxylated acrylic emulsion with a brand name of CX-822 produced by Jining Fangyu Chemical Co., Ltd. In step (1), the curing agent is Evonik B1530 curing agent.

6. The preparation method according to claim 1, characterized in that: In step (2), the aqueous polyurethane resin emulsion is an aqueous polyurethane resin emulsion with a brand number of 1099R produced by Jining Fangyu Chemical Co., Ltd.

7. The preparation method according to claim 1, characterized in that: In step (2), the aqueous hydroxylated acrylic emulsion is an aqueous hydroxylated acrylic emulsion with a brand number of CX-822 produced by Jining Fangyu Chemical Co., Ltd.

8. The preparation method according to claim 1, characterized in that: In step (2), the curing agent is Evonik B1530 curing agent.

9. The preparation method according to claim 1, characterized in that: In step (3), the polyurethane modified acrylic resin is preferably prepared by the following method: mixing hydroxy acrylate and isocyanate and heating them to react to obtain a polyurethane prepolymer; adding an organic solvent and polymerizing the polyurethane prepolymer with methyl methacrylate to obtain the polyurethane modified acrylic resin.

10. An architectural coating prepared by the preparation method according to any one of claims 1 to 9.

Images