CN111534169A

CN111534169A - Preparation method of environment-friendly water-based acrylic coating

Info

Publication number: CN111534169A
Application number: CN201911393415.9A
Authority: CN
Inventors: 崔玉民; 殷榕灿; 胡向阳; 储陆峰; 李慧泉
Original assignee: Fuyang Normal University
Current assignee: Fuyang Normal University
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-08-14

Abstract

The invention provides an environment-friendly water-based acrylic coating and a preparation method thereof, wherein the preparation method comprises the following steps: mixing the raw materials to obtain a mixture I, and then mixing the mixture I with the water-based acrylic resin and the additive in sequence to finally obtain the environment-friendly water-based acrylic coating. The environment-friendly water-based acrylic coating prepared by the invention has excellent comprehensive performance and higher formaldehyde photocatalytic degradation efficiency, so that the environment-friendly water-based acrylic coating prepared by the invention can be applied to the field of environment protection.

Description

Preparation method of environment-friendly water-based acrylic coating

Technical Field

The invention relates to the field of water-based paint, in particular to a preparation method of environment-friendly water-based acrylic paint.

Background

In the 20 th century and 80 th century, the development speed of industrialization of polyacrylate coatings is greatly increased due to successive production and application of acrylate monomers, and with rapid development of science and technology, people have deeper understanding and understanding on acrylic resin and promoted development and application of the acrylic resin in the coating industry. To date, acrylic resin has been developed into a paint variety with the most types and the most comprehensive performance, which has both excellent decorative performance and good protective performance, and especially, the long-history solvent type acrylic resin plays a very important role.

The prepared water-based acrylic coating has the advantages of simple synthesis and processing, low price, safety, environmental protection, excellent aging resistance, good alkali resistance and the like, and is applied to the aspects of fire prevention, water prevention, pollution prevention, corrosion prevention, heat insulation and preservation and the like. Although aqueous acrylic coatings have excellent properties and are used quite widely, their problems have affected their rapid development.

In recent years, with the improvement of living standard, people have higher requirements on comfort level, aesthetic degree and air quality of living environment, so that the coating with environmental protection performance is more and more popular with people, and naturally becomes a research hotspot in the coating field. Therefore, how to utilize the excellent performance of the water-based acrylic coating and improve the environmental protection performance and the comprehensive performance of the water-based acrylic coating through modification becomes a problem to be solved urgently.

Disclosure of Invention

Based on the technical background, the inventor of the invention has made a sharp approach, and other modification auxiliary agents are added into the water-based acrylic resin, and the environment-friendly water-based acrylic coating is finally prepared through treatment.

The invention provides a preparation method of an environment-friendly water-based acrylic coating, which comprises the following steps:

(1) mixing the raw materials to obtain a mixture I;

(2) mixing the mixture I with water-based acrylic resin to obtain a water-based acrylic coating;

(3) mixing the water-based acrylic paint with an additive to obtain a mixture II;

(4) and filtering the mixture II to obtain the environment-friendly water-based acrylic coating.

The second aspect of the invention is to provide the environment-friendly water-based acrylic coating prepared by the preparation method of the first aspect of the invention and application thereof.

The preparation method of the environment-friendly water-based acrylic coating and the water-based acrylic coating prepared by the preparation method have the following advantages:

(1) the environment-friendly water-based acrylic coating prepared by the invention has excellent adhesive force, higher hardness, excellent water resistance and impact resistance, and particularly high hardness;

(2) the environment-friendly water-based acrylic coating prepared by the invention has good performance of photocatalytic degradation of pollutants, and has certain degradation capability on formaldehyde;

(3) the environment-friendly water-based acrylic coating prepared by the invention has excellent environment-friendly performance and low preparation cost, and can be used as an environment-friendly coating.

Drawings

FIG. 1 shows a graph of the ultraviolet photocatalytic activity of aqueous coating photocatalytic degradation of formaldehyde prepared by tungsten trioxide with different doping amounts;

FIG. 2 shows XRD spectra of water-based paint prepared by different doping amounts of tungsten trioxide;

FIG. 3 is a graph showing photoluminescence spectra of aqueous coatings prepared by different doping amounts of tungsten trioxide;

FIG. 4 shows an infrared spectrum of a water-based paint prepared by different doping amounts of tungsten trioxide;

FIG. 5 shows the UV-VIS diffuse reflectance spectra of the water-based paint prepared by different doping amounts of tungsten trioxide.

Detailed Description

The present invention will be described in detail below, and features and advantages of the present invention will become more apparent and apparent with reference to the following description.

(1) mixing the raw materials to obtain a mixture I;

This step is specifically described and illustrated below.

And (2) mixing the raw materials to obtain a mixture I.

In step (1) of the present invention, the mixing is mechanical mixing, preferably stirring mixing, and more preferably mixing in a stirrer.

In order to mix the raw materials more uniformly and disperse the materials more effectively, in a preferred embodiment of the present invention, zirconium beads are added to the mixer during mixing in the mixer.

The zirconium beads are added during stirring, so that the mixed material can be rapidly dispersed, the dispersion efficiency of the mixed material is improved, and the dispersion effect of the mixed material is better after the zirconium beads are added.

In the step (1), the raw materials comprise titanium dioxide, calcium carbonate, a defoaming agent and a water-based dispersing agent.

The defoaming agent is selected from polydimethylsiloxane, polyoxyethylene polyoxypropylene amine ether and a higher alcohol fatty acid ester compound, and preferably, the defoaming agent is the higher alcohol fatty acid ester compound.

The high-carbon alcohol fatty acid ester compound has the advantages of low price, good defoaming effect, no corrosiveness, nonflammability, non-volatility, stable property and the like, not only effectively reduces the preparation cost, but also has safe preparation process and effectively improves the preparation effect.

The aqueous dispersant is selected from sulfate ester salts, alkyl quaternary ammonium salts, organic siloxane and the like, preferably alkyl quaternary ammonium salts, and more preferably cetyl trimethyl ammonium bromide. The water-based dispersant is mainly used for wetting particles to reduce the surface tension of the particles, so that the materials are mixed more uniformly.

The addition amounts of the raw materials and the zirconium beads are as follows: based on 100 parts by weight of the titanium dioxide,

preferably, based on 100 parts by weight of titanium dioxide, the addition amounts of the raw materials and the zirconium beads are as follows:

more preferably, based on 100 parts by weight of titanium dioxide, the addition amounts of the raw materials and the zirconium beads are as follows:

and stirring and mixing the weighed raw materials and the zirconium beads, wherein the stirring speed is 1700-2300 r/min, preferably 1800-2200 r/min, and more preferably 2000 r/min.

The stirring speed is 45-75 min, preferably 50-70 min, and more preferably 60 min.

And filtering the mixed and stirred raw materials by using a gauze to obtain a mixture I, and preferably filtering by using a 100-mesh gauze.

And (3) mixing the mixture I with water-based acrylic resin to obtain the water-based acrylic coating.

Mixing the mixture I and water-based acrylic resin, wherein the adding amount of the water-based acrylic resin is 250-350 parts by weight, preferably 270-330 parts by weight, more preferably 290-310 parts by weight, for example 300 parts by weight, based on 100 parts by weight of titanium dioxide.

And stirring the weighed mixture I and the water-based acrylic resin, wherein the stirring is mechanical stirring, and the stirring is preferably performed in a stirrer.

The stirring time is 5-20 min, preferably 10 min. Stirring to obtain the water-based acrylic paint.

And (4) mixing the water-based acrylic paint and the additive in the step (3) to obtain a mixture II.

In step (3) of the present invention, the additive comprises a modification aid and a defoaming agent, and the modification aid is a metal compound, preferably a metal oxide, and more preferably tungsten trioxide.

Tungsten trioxide is used as an inorganic semiconductor material, the bandwidth of bulk tungsten oxide of the tungsten trioxide is 2.8eV, and the tungsten trioxide has attracted general attention due to unique physicochemical properties and wide application in the fields of gas sensitivity, photocatalysis, electrochromism, photochromism, field emission and the like. Particularly, the tungsten trioxide has good light absorption efficiency in a visible light waveband, has good thermal stability and chemical stability, and is expected to be applied to the field of photocatalysis. Therefore, in the present invention, tungsten trioxide is added as a modification aid to an aqueous acrylic coating material, and the aqueous acrylic coating material modified is desired to have excellent photocatalytic performance so as to be capable of photocatalytic degradation of formaldehyde, and to be used as a novel photocatalytic coating material.

The purpose of adding the defoaming agent is to reduce the surface tension and enable the modification auxiliary agent to be more uniformly dispersed in the water-based acrylic coating, thereby improving the comprehensive performance of the finally prepared environment-friendly water-based acrylic coating.

The addition amount of the modification auxiliary agent is as follows: the modifying assistant accounts for 0.1-20% of the water-based acrylic coating, preferably 0.2-15%, and more preferably 0.5-12%. The water resistance and the impact resistance of the water-based acrylic coating can be effectively improved by adding the modification auxiliary agent into the water-based acrylic coating, particularly the hardness and the photocatalytic degradation performance of the water-based acrylic coating are greatly improved, but the hardness and the impact resistance are reduced due to excessively high doping amount, so that the comprehensive performance of the finally prepared water-based acrylic coating is reduced.

In the present invention, the amount of the defoaming agent added is 0.1 to 8mL, preferably 0.5 to 5mL, more preferably 1 to 4mL, for example 3mL, based on 100g of the aqueous acrylic coating.

In order to mix the water-based acrylic paint and the additive more uniformly, the water-based acrylic paint and the additive are stirred, and the stirring is mechanical stirring, preferably stirring in a high-speed stirrer.

The stirring speed is 700-1500 r/min, preferably 900-1300 r/min, and more preferably 1000-1200 r/min; for example 1100 r/min.

The stirring time is 10-90 min, preferably 15-60 min; more preferably 20 to 45min, for example 30 min. Stirring to obtain a mixture II.

And (4) filtering the mixture II to obtain the environment-friendly water-based acrylic coating.

The filtering is performed by using gauze, preferably 100-300 mesh gauze, more preferably 100-200 mesh gauze, for example 100 mesh gauze.

The second aspect of the invention is to provide the environment-friendly water-based acrylic coating prepared by the preparation method of the first aspect of the invention and application thereof. The hardness of the environment-friendly water-based acrylic coating prepared by the invention can reach 5H, the water absorption rate is only 1.11%, the impact resistance height of the front surface is 35cm, the impact resistance height of the back surface is 26cm, and the photocatalytic degradation rate of the coating to formaldehyde is 25.1%.

The invention has the following beneficial effects:

(1) the environment-friendly water-based acrylic coating prepared by the invention has excellent water resistance, when the addition amount of tungsten trioxide is 10%, the water absorption is 1.11%, and the contact angle is 79.03 degrees;

(2) the environment-friendly water-based acrylic coating prepared by the invention has excellent impact resistance, the front impact height is 35cm, and the back impact height is 26 cm;

(3) the environment-friendly water-based acrylic coating prepared by the invention has high hardness, and the highest hardness can reach 5H;

(4) the environment-friendly water-based acrylic coating prepared by the invention can degrade formaldehyde by photocatalysis, the illumination time is 160min, and the formaldehyde degradation rate is 25.1%;

(5) the method for preparing the environment-friendly water-based acrylic coating is simple and low in cost, and the prepared environment-friendly water-based acrylic coating has strong capability of degrading pollutants by photocatalysis, thereby widening the way for the application of the water-based acrylic coating in the field of environment protection.

Examples

The invention is further illustrated by the following specific examples, which are intended to be illustrative only and not limiting to the scope of the invention.

Example 1 preparation of waterborne acrylic coatings

Putting 100g of titanium dioxide and 50g of calcium carbonate into a stirrer, adding 100g of water, 2g of higher alcohol fatty acid ester compound and 2g of hexadecyl trimethyl ammonium bromide, then adding 100g of zirconium beads, starting the stirrer, stirring at the speed of 2000r/min, grinding for 60min, filtering by using a 100-mesh gauze, stirring the filtrate and 300g of water-based resin in the stirrer for 10min, and mixing to obtain the white water-based acrylic coating.

Example 2 incorporation of 0.5% tungsten trioxide

Adding 1g of tungsten trioxide and 6mL of higher alcohol fatty acid ester compound into 200g of water-based acrylic paint, mixing, stirring by using a high-speed dispersion machine at the stirring speed of 1100r/min for 30min, filtering by using a 100-mesh gauze after stirring, and finally preparing the environment-friendly water-based acrylic paint.

Example 3 incorporation of 1% tungsten trioxide

The same procedure as in example 2 was conducted except that the addition amount of tungsten trioxide was 2 g.

Example 4 incorporation of 2% tungsten trioxide

The same procedure as in example 2 was conducted except that the addition amount of tungsten trioxide was 4 g.

Example 5 incorporation of 5% tungsten trioxide

The same procedure as in example 2 was conducted except that the addition amount of tungsten trioxide was 10 g.

Example 6 incorporation of 6% tungsten trioxide

The same procedure as in example 2 was conducted except that the amount of tungsten trioxide added was 12 g.

Example 7 incorporation of 10% tungsten trioxide

The same procedure as in example 2 was conducted except that the addition amount of tungsten trioxide was 20 g.

Examples of the experiments

Experimental example 1 coating adhesion test

The adhesion of the paint film means the degree of fastness of the paint film to the surface of the object to be coated. The bonding force is formed by the interaction of polar groups of the polymer in the paint film and polar groups on the surface of the coated object. The specific operation steps are as follows: and (2) polishing the surface of the tinplate by using abrasive paper, cleaning the polished tinplate by using absolute ethyl alcohol, spraying a coating on the polished face of the tinplate after drying, drying for 4-5h at normal temperature after spraying, putting into an oven at 80 ℃ for drying for 4h, taking out, and naturally cooling for 5-6 h.

The test of the adhesive force of the paint film adopts a grid cutting method, and the specific operation mode is as follows: and (3) scribing a # -shaped scribing lattice on the painted galvanized iron sheet paint film sample by using a paint film scribing instrument, adhering the iron sheet paint film sample scribed with the # -shaped scribing lattice by using an adhesive tape, and observing the change of the scribed lattice. No paint film falls off to 0 grade, a small amount of paint film falls off to 1 grade, and a large amount of paint film falls off to 2 grades in the cross-shaped grids. The results are shown in Table 1.

TABLE 1 Change in adhesion of tungsten trioxide-modified waterborne acrylic coating films

As can be seen from Table 1, when no tungsten trioxide, 0.5% and 1% of tungsten trioxide were added to the coating, the water-based acrylic coating had excellent adhesion, the adhesion reached level 0, no paint film falling, and when the amounts of tungsten trioxide added to the coating were 2%, 5%, 6% and 10%, the adhesion was level 1, and there was less paint film falling.

Experimental example 2 coating hardness test

Paint film hardness refers to the ability of a paint film to locally resist hard objects being pressed into its surface, and this ability is an indicator for judging whether the paint film is soft or hard. The specific test method is to adopt a pencil hardness method for measurement, and the specific method comprises the following steps: the surface of a tin iron plate paint film sample is sequentially scratched by B-type, HB-type, H-type, 2H-type, 3H-type, 4H-type and 5H-type pencils at an angle of 45 degrees, the surface condition of the iron plate paint film sample is observed, and when the paint film surface has obvious scratches, the former pencil type is the hardness of the paint film. The results are shown in Table 2.

TABLE 2 hardness measurement results of the tungsten trioxide modified waterborne acrylic coating film

As can be seen from Table 2, the hardness of the paint film is significantly increased by adding tungsten trioxide to the paint, indicating that the addition of tungsten trioxide helps to increase the hardness of the paint film. When the doping amount of the tungsten trioxide is 0.5% and 1%, the hardness of the paint film is maximum and reaches 5H, and when the doping amount of the tungsten trioxide is 2%, the hardness of the paint film is 4H.

Experimental example 3 Water absorption test of coating

The specific operation steps are as follows: and (2) polishing the surface of the tinplate by using abrasive paper, cleaning the polished tinplate by using absolute ethyl alcohol, spraying a coating on the polished face of the tinplate after drying, drying for 4-5h at normal temperature after spraying, putting into an oven at 80 ℃ for drying for 4h, taking out, and naturally cooling for two days.

Before the water absorption test of the coating, the drawing board is subjected to edge sealing, the width of the drawing board is 2-3mm, and the weight of the iron plate at the moment is weighed and recorded as m₀Putting the coated iron plate into a glass container, adding distilled water until the iron plate is submerged, taking out the coated iron plate after 24 hours, immediately sucking the distilled water on the coated iron plate by using filter paper, and weighing the mass m₁。

The water absorption of the coating is calculated according to the formula: water absorption (%) - (m)₁-m₀)/m₀× 100% 100 the results are shown in table 3.

TABLE 3 Water absorption determination results of tungstic oxide modified waterborne acrylic paint film

As can be seen from table 3, when tungsten trioxide was added to the aqueous acrylic coating material, the water absorption of the aqueous acrylic coating material decreased, and the water absorption of the aqueous acrylic coating material showed a significant decrease tendency as the amount of tungsten trioxide added increased, and the water resistance of the coating layer was improved. It was demonstrated that the addition of tungsten trioxide to a water-based acrylic paint can effectively reduce the water absorption of the water-based paint. When the addition amount of tungsten trioxide was 2%, the water absorption of the water-based paint was 1.27%.

Experimental example 4 coating impact resistance test

Impact resistance of a coating refers to the ability of a coating sample to resist the action of an impact load. The impact resistance test method and the evaluation standard of the coating are shown in GB/T1732-1993 paint film impact resistance determination method. Wherein, the recoil test comprises the following steps: and (3) placing the surface coated with the coating downwards on a base of the impact instrument, checking whether the impacted convex surface coating falls off or not by using a method such as a forward impact test, and finding out the maximum height without falling off and recording as the impact resistance. The results are shown in Table 4.

TABLE 4 determination results of impact resistance of tungsten trioxide modified waterborne acrylic coating

As can be seen from Table 4, the impact resistance (both forward impact and reverse impact) of the aqueous acrylic coating was enhanced by adding tungsten trioxide to the aqueous acrylic coating, and when the amount of tungsten trioxide added was 2%, the impact resistance of the coating film was maximized, and the front impact height and the back impact height were 35cm and 26cm, respectively.

EXAMPLE 5 coating contact Angle test

The treated coating plate is horizontally placed on a drip table, corresponding software is started, a knob is slowly rotated after debugging is finished, so that water drops appear at the lower opening of a capillary tube, the process is stopped when the water drops slightly shake like drops and do not drip, then the drip table is lifted, when the coating plate is about to contact with the water drops, the coating plate slowly rises, the surface of the coating plate is slightly tangent to the water drops, images are fixed when the water drops images in the screen are static, two points and the highest point of the edge where the water drops contact with the coating plate are taken from the images, and a contact angle is obtained. The results are shown in Table 5.

TABLE 5 contact angle measurement results of paint film of tungsten trioxide-modified waterborne acrylic coating

As can be seen from table 5, the contact angle of the coating layer becomes larger as the content of tungsten trioxide increases, the contact angle of the coating layer is 74.56 ° when the mass ratio of tungsten trioxide to the aqueous acrylic coating material is 2%, and the contact angle of the coating layer reaches the maximum of 79.03 ° when the mass ratio of tungsten trioxide to the aqueous acrylic coating material is 10%, which indicates that tungsten trioxide has an enhancing effect on the hydrophobicity of the coating layer surface, further indicating that the hydrophobicity of the coating material is significantly improved due to the addition of tungsten trioxide. The tungsten trioxide has a special nano structure, so that invasion of water molecules can be effectively prevented, and the water resistance of the coating is improved.

Experimental example 6 photocatalytic degradation Performance test

(1) Photocatalytic degradation experiment

In the experiment, a photochemical reaction instrument is used for carrying out photocatalytic degradation on the formaldehyde solution added with the water-based acrylic coating under the irradiation of a mercury lamp, and the formaldehyde solution without the coating is used for comparison. Before the experiment, 10mg/L of formaldehyde solution is prepared, 40mL of formaldehyde solution is added into 5 quartz tubes marked as No. 1, No. 2, No. 3, No. 4 and No. 5 quartz tubes respectively, No. 1 quartz tube is not treated, and then WO with different contents is added into the remaining 4 quartz tubes respectively₃50mg of the aqueous acrylic coating composition (2). When the experiment is started, 5 quartz tubes are placed in a reaction box, a magnetic stirrer is started, dark reaction is carried out for 30min, then 5mL of solution is taken out from each tube, the rotating speed of a centrifugal machine is adjusted to 14000r/min, centrifugation is carried out twice, and supernatant is taken for later use. Then, the mercury lamp was turned on, 5mL of the solution was taken every 20min, and the above centrifugation was repeated to take out the supernatant each time for use.

(2) Method for measuring content of formaldehyde in aqueous solution by acetylacetone spectrophotometry

The yellow compound formed by formaldehyde and acetylacetone in excess of ammonium salt was spectrophotometrically measured at 414 nm. The supernatant from the photocatalytic experiment was taken in a 25mL graduated tube with a plug and diluted with water to the mark. Adding 2.5mL of acetylacetone solution, shaking, heating in 55 deg.C water bath for 30min, and cooling. Zeroing with 1cm cuvette at wavelength of 414nm with water as reference, and measuring absorbance A_t

Before the photocatalytic experiment is started, taking the undegraded formaldehyde solution to carry out the previous step, and measuring the initial absorbance A₀. The degradation rate calculation formula is as follows:

η＝(A₀-A_t)/A₀

the results are shown in FIG. 1. In the figure, formaldehyde, 0%, 0.5%, 1% and 2% represent a formaldehyde solution to which no coating material is added, a water-based acrylic coating material not doped with tungsten trioxide, and water-based acrylic coating materials doped with 0.5%, 1% and 2% of tungsten trioxide, respectively.

As can be seen from FIG. 5, the waterborne acrylic coating has a certain degradation capability to formaldehyde, but the degradation capability is poor, and WO is added into the waterborne coating₃Can enhance the formaldehyde degradation capability of the water-based paint, and is accompanied with WO₃The content is increased, and the photocatalytic degradation rate of formaldehyde is gradually increased, wherein when WO is adopted₃When the mass ratio is 2 percent, the light irradiation is 160min, the efficiency of the photocatalytic degradation of formaldehyde reaches 25.1 percent, which shows that the WO is caused₃The addition of the acrylic acid resin enhances the photocatalytic degradation capability of the water-based acrylic acid coating on formaldehyde and improves the comprehensive performance of the coating.

Experimental example 7 characterization by X-ray powder diffraction (XRD)

Taking small amount of undoped WO₃Coating of (2), doped with 0.5% WO₃Coating material of (2%) doped WO₃Coating of (2) doped with 5% of WO₃Coating of (2) doped with 6% of WO₃Coating and doping with 10% WO₃The paint sample (powder) of (1) was analyzed using a Bruker D8 Advance type X-ray diffractometer (XRD), a copper target (Cu K α (λ 0.154nm)) ray, a Ni filter, a working voltage of 40kV, a current of 40mA, a scanning range of 2 θ 10 to 80 °, and a sample analysisThe crystal phase structure of (1). The results are shown in FIG. 2. 0%, 0.5%, 2%, 5%, 6% and 10% in the figure represent undoped tungsten trioxide, 0.5%, 2%, 5%, 6% and 10% doped tungsten trioxide, respectively, in the aqueous acrylic coating.

It can be seen from fig. 1 that several groups of samples all have distinct diffraction peaks at 22.72 °, 24.33 °, 28.17 ° and 33.58 ° 2 θ, corresponding to WO₃The (001), (110), (200) and (111) crystal planes of the hexagonal crystal form (PDF # 33-1387). Illustrating the introduction of WO₃The main structure of the original water-based acrylic paint is not damaged. We have also found that WO may be added₃The diffraction peak at 22.72 ℃ after, which is dependent on the WO added₃The increase in the content and the increase in the intensity of the diffraction peak indicate that WO was added₃The water-based acrylic paint is modified to a certain degree.

Experimental example 8 photoluminescence Spectroscopy characterization

Taking small amount of undoped WO₃Coating of (2), doped with 0.5% WO₃Coating material of (1%) WO₃Coating material of (2%) doped WO₃Coating of (2) doped with 5% of WO₃Coating of (2) doped with 6% of WO₃Coating of (2) doped with 10% of WO₃The coating samples (powders) of (a) were tested for their photoluminescent properties using a fluorescence spectrometer. The excitation wavelength is 445nm, and the scanning range is 380-700 nm. In the experiment, the sample should be pressed as densely as possible by using a glass slide to keep the surface of the sample flat, and one sample should be tested at least twice in parallel to ensure the validity of the data. The photoluminescence performance of various catalyst samples is detected by a fluorescence spectrometer. The results are shown in FIG. 3. In the figure, 0%, 0.5%, 1%, 2%, 5%, 6% and 10% respectively represent the tungsten trioxide doped in the aqueous acrylic coating material without tungsten trioxide, and 0.5%, 1%, 2%, 5%, 6% and 10% respectively.

Photoluminescence spectra can be used for effectively evaluating the separation efficiency and the electron transfer effect in the photocatalyst. FIG. 3 is a photoluminescence spectrum of a sample with an excitation light source having a wavelength of 445 nm.

As can be seen in fig. 3, the coating doped with tungsten trioxide produced a sequence of peak intensities: doping with 10% WO₃<Doping with 6% WO₃<Doping with 5% WO₃<Doping with 2% WO₃<Doping with 1% WO₃<0.5％WO₃<Undoped WO₃. It is generally accepted that the stronger the fluorescence signal, the correspondingly lower the photocatalytic activity. It can be understood from fig. 3 that the photocatalytic activity of the aqueous acrylic coating material can be improved by doping tungsten trioxide in the aqueous acrylic coating material, and the photocatalytic activity of the sample gradually increases with the increase in the content of tungsten trioxide in the aqueous acrylic coating material, and the catalytic activity of the sample is the highest when the mass ratio of tungsten trioxide to the aqueous acrylic coating material is 10%.

Experimental example 9 Infrared Spectroscopy characterization

Taking small amount of undoped WO₃Coating material of (1%) WO₃Coating material of (2%) doped WO₃Coating of (2) doped with 5% of WO₃Coating of (2) doped with 6% of WO₃Coating of (2) doped with 10% of WO₃Respectively adding a small amount of potassium bromide powder into the coating sample (powder), grinding until the mixture is uniformly mixed, pressing into a sheet, and performing infrared spectrum characterization on the catalyst by using a Fourier transform infrared spectrometer. The results are shown in FIG. 4. In the figure, 0%, 1%, 2%, 5%, 6% and 10% represent the non-doping of tungsten trioxide, the doping of tungsten trioxide at 1%, 2%, 5%, 6% and 10% respectively in the aqueous acrylic coating.

As can be seen from FIG. 4, WO was added₃And without addition of WO₃The coating has consistent chemical structure, but the peak intensity is different, and the wave number is 1500-^-1Is located at C-H bending vibration peak, and has wave number of 3300-^-1Has a broad absorption peak, which is the characteristic absorption peak of hydroxyl. From the figure we can see that WO is added₃With no WO addition₃The positions of the infrared spectrum absorption peaks of the water-based paint are basically consistent, but the intensities of the absorption peaks are slightly different, which indicates that WO is added₃And no WO was added₃Should have substantially the same structure, and the WO added₃Has certain influence on the water paint.

Experimental example 10 characterization of UV-visible Diffuse reflectance

Taking small amount of undopedWO₃Coating of (2), doped with 0.5% WO₃Coating material of (1%) WO₃Coating material of (2%) doped WO₃Coating of (2) doped with 5% of WO₃Coating of (2) doped with 6% of WO₃Coating of (2) doped with 10% of WO₃The coating sample (powder) is characterized by an ultraviolet-visible diffuse reflectance spectrometer, and the test wavelength is 250-800 nm. The results are shown in FIG. 5. In the figure, 0, 0.5%, 1%, 2%, 5%, 6% and 10% respectively represent that the aqueous acrylic coating material is not doped with tungsten trioxide, and is doped with tungsten trioxide in an amount of 0.5%, 1%, 2%, 5%, 6% and 10%.

As can be seen from FIG. 5, WO was not added₃And adding WO₃The water-based paint has stronger ultraviolet absorption at the position of 250-400 nm, and the absorption characteristics are basically the same, further explaining that WO is added₃The basic structure of the coating is not damaged. As can also be seen in FIG. 5, the addition of WO₃Can improve the absorption of the water-based paint to ultraviolet light, and along with WO₃The increasing content of the water-based paint tends to gradually increase the absorption of ultraviolet light, which indicates that the WO is added₃The light absorption ability of the coating can be enhanced. Also, as can be seen from FIG. 5, no WO is added₃Comparing the ultraviolet spectrum of the coating, adding WO₃The ultraviolet spectrum of the coating generates red shift, which shows that the coating has wider absorption range to light and enhanced photocatalytic performance.

The invention has been described in detail with reference to specific embodiments and illustrative examples, but the description is not intended to be construed in a limiting sense. Those skilled in the art will appreciate that various equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its embodiments without departing from the spirit and scope of the present invention, which fall within the scope of the present invention. The scope of the invention is defined by the appended claims.

Claims

1. The preparation method of the environment-friendly water-based acrylic coating is characterized by comprising the following steps:

(1) mixing the raw materials to obtain a mixture I;

(4) and carrying out post-treatment on the mixture II to obtain the environment-friendly water-based acrylic coating.

2. The production method according to claim 1, wherein, in the step (1),

the mixing is mechanical mixing, preferably stirring mixing, and more preferably mixing in a stirrer;

the raw materials comprise titanium dioxide, calcium carbonate, a defoaming agent and a water-based dispersing agent.

3. The production method according to claim 2, wherein, in the step (1),

before mixing the raw materials, the zirconium beads are added into the raw materials and then mixed.

4. The production method according to claim 2, wherein, in the step (1),

preferably, the addition amounts of the raw materials and the zirconium beads are: based on 100 parts by weight of the titanium dioxide,

5. the production method according to claim 2, wherein, in the step (1),

the stirring speed is 1700-2300 r/min, preferably 1800-2200 r/min;

the stirring speed is 45-75 min, preferably 50-70 min;

and filtering the mixed and stirred raw materials by using gauze to obtain a mixture I.

6. The production method according to claim 1, wherein, in the step (2),

the mixture I and the water-based acrylic resin are mixed according to the following ratio: the addition amount of the water-based acrylic resin is 250-350 parts by weight, preferably 270-330 parts by weight, and more preferably 290-310 parts by weight based on 100 parts by weight of titanium dioxide.

7. The production method according to claim 1, wherein, in the step (3),

the additive comprises a modification auxiliary agent and a defoaming agent, wherein the modification auxiliary agent is a metal compound, preferably a metal oxide;

the addition amount of the modification auxiliary agent is as follows: the modifying assistant accounts for 0.1-20% of the water-based acrylic coating, preferably 0.2-15%, and more preferably 0.5-12%.

8. The production method according to claim 7, wherein, in the step (3),

stirring the water-based acrylic paint and the additive, wherein the stirring is mechanical stirring, preferably stirring in a high-speed stirrer; stirring to obtain a mixture II;

the stirring speed is 700-1500 r/min, preferably 900-1300 r/min, and more preferably 1000-1200 r/min;

the stirring time is 10-90 min, preferably 15-60 min; more preferably 20 to 45 min.

9. The production method according to claim 1, wherein, in the step (4),

the filtering is performed by using gauze, preferably 100-300 meshes of gauze, and more preferably 100-200 meshes of gauze.

10. The environmental-friendly water-based acrylic coating prepared by the preparation method according to one of claims 1 to 9 and the application thereof are characterized in that,

the environment-friendly water-based acrylic coating has high hardness and water resistance, has high efficiency of degrading formaldehyde through photocatalysis, and can be used as an environment-friendly coating.