Low-temperature self-film-forming real stone paint without coalescing agent and preparation method of low-temperature self-film-forming real stone paint

Abstract

The invention relates to a low-temperature self-film-forming real stone paint without a coalescing agent. The low-temperature self-film-forming real stone paint without the coalescing agent is prepared from the following components: a low-temperature self-film-forming emulsion, modified bentonite, cellulose, modified colored sand, an auxiliary agent and water, a butyl acrylate polymerization product is used as a core structure, then dodecafluoroheptyl methacrylate, butyl acrylate, methyl methacrylate and hydroxyethyl acrylate are subjected to a polymerization reaction to be used as a shell structure, and the fluorocarbon emulsion of the core-shell structure is obtained. Introducing an acrylate chain segment, a fluorine-containing acrylate chain segment and a hydroxyl group into the fluorocarbon emulsion; firstly, due to the introduction of a large number of polar groups such as hydroxyl, the hydrogen bond density of the modified bentonite is improved, and components such as cellulose and the modified bentonite generate strong hydrogen bond interaction, so that the compatibility of the modified bentonite in the components of the real stone paint is effectively improved, and the binding force among the components is also improved; the compactness and the hydrophobicity of the real stone paint are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and particularly to a film-forming assistant-free low-temperature self-film-forming real stone paint and a preparation method thereof. Background Art

[0002] As a new type of water-based environmental protection sand-wall type architectural coating, real stone paint does not have overly cumbersome construction procedures, which can greatly shorten the construction period and quickly deliver the exterior wall decoration operation of the building. Compared with the same type of coating construction operation, real stone paint can use a real stone paint spray gun to achieve rapid spraying in a regionalized manner, with higher efficiency and better spraying effect than traditional manual painting of coatings. Moreover, real stone paint is relatively inexpensive, which can reduce costs and is favored by a large number of customers.

[0003] However, when traditional real stone paint is constructed in autumn and winter seasons and in low-temperature and high-humidity areas, there are often a series of problems such as slow drying speed of the paint film, low initial strength, and poor water whitening resistance. The drying process of the paint film is generally a process of volatilization of water and solvents in the wet film. The commonly used alcohol ester twelve (C-12) film-forming assistant has a relatively high boiling point, and has a large degree of swelling on the dispersed particles. Part of it can form an association with the hydrophobic groups in the resin, making its volatilization in the paint film slow down. Therefore, the drying speed of real stone paint added with alcohol ester twelve film-forming assistant will become slower. The main function of the film-forming assistant dodecyl alcohol ester is to promote the plastic flow and elastic deformation of the polymer, improve its coalescence performance, lower the MFT (minimum film-forming temperature) of the coating, and achieve a balance between high performance and low construction temperature, so that the coating can form a film within a relatively wide construction temperature range. Therefore, if the film-forming assistant is not added, the coating cannot form a film well.

[0004] Therefore, it is necessary to develop a film-forming assistant-free low-temperature self-film-forming real stone paint. Summary of the Invention

[0005] Based on this, the present invention has developed a film-forming assistant-free low-temperature self-film-forming real stone paint and a preparation method thereof. This paint uses a core-shell structured fluorocarbon emulsion, modified bentonite, and modified colored sand as raw materials. This real stone paint has the advantages of low-temperature self-film-forming, rain mark resistance, and fast initial drying speed, and has good application prospects.

[0006] An object of the present invention is to provide a film-forming assistant-free low-temperature self-film-forming real stone paint, and the film-forming assistant-free low-temperature self-film-forming real stone paint comprises components in the following parts by mass:

[0007]

[0008]

[0009] Among them, the modified bentonite is bentonite modified with dodecafluoroheptyl methacrylate;

[0010] The fluorocarbon emulsion is an acrylate emulsion with a fluorinated core-shell structure;

[0011] The modified colored sand is colored sand modified with a silane coupling agent.

[0012] Specifically, the modified bentonite of the present invention can endow the paint film with good hydrophobicity, and the surface of the paint film has a lotus leaf hydrophobic effect. Rainwater is not easily penetrated into the coating, and water droplets are formed on the surface of the paint film and roll down, improving the rain mark resistance of the paint film.

[0013] Specifically, the colored sand is a mixture of colored sand with a mesh number of 40-80 meshes and 80-120 meshes, and the colored sand with 40-80 meshes accounts for 25-30% of the total weight of the colored sand.

[0014] Furthermore, the cellulose is selected from one or more of hydroxyethyl cellulose and hydroxymethyl cellulose.

[0015] Preferably, the cellulose is hydroxyethyl cellulose.

[0016] Furthermore, the auxiliary agent is selected from one or more of an antifoaming agent, a bactericide, a pH regulator, an antifreezing agent, and a thickener.

[0017] Furthermore, the bactericide is selected from one or more of isothiazolinones, benzisothiazolines, and s-triazines.

[0018] Furthermore, the pH regulator is selected from one or more of organic basic regulators and organosilicon regulators.

[0019] Furthermore, the thickener is selected from one or more of alkali-swellable thickeners and polyurethane thickeners.

[0020] Preferably, the thickener is a polyurethane thickener.

[0021] Specifically, the present invention selects the combination of hydroxyethyl cellulose and polyurethane thickener, so that the real stone paint has good atomization during construction spraying, and has good anti-settling water separation property and spraying anti-splashing property. By adding special modified bentonite, the coating has excellent thixotropy and paint film hydrophobicity, improving the rain mark resistance of the paint film.

[0022] Preferably, the antifreezing agent is ethylene glycol.

[0023] Preferably, the antifoaming agent is a mineral oil antifoaming agent.

[0024] The present invention also provides a preparation method of the low-temperature self-forming real stone paint without a film-forming auxiliary agent, comprising the following steps:

[0025] S1. Add ammonium persulfate, polyvinyl alcohol, sodium dodecylbenzenesulfonate, and sodium bicarbonate into a solvent, then add butyl acrylate, and heat for reaction to obtain a seed emulsion;

[0026] S2. Add ammonium persulfate, methyl methacrylate, 2-hydroxyethyl acrylate, butyl acrylate, and dodecafluoroheptyl methacrylate into a solvent, mix evenly, then add into the seed emulsion, and heat for reaction to obtain a fluorocarbon emulsion;

[0027] S3. Immerse bentonite in a solvent, disperse it by ultrasonic wave, then add silane coupling agent KH570, and heat for reaction to obtain pretreated bentonite;

[0028] S4. Under the protection of an inert gas, disperse the pretreated bentonite in a solvent, add dodecafluoroheptyl methacrylate, acrylic acid, and an initiator, and heat for reaction to obtain modified bentonite;

[0029] S5. Under the protection of an inert gas, add colored sand into a solvent, then add silane coupling agent KH560, and heat for reaction to obtain modified colored sand;

[0030] S6. Blend the fluorocarbon emulsion, modified bentonite, and modified colored sand with other components to obtain a low-temperature self-forming real stone paint without a film-forming aid.

[0031] Further, in step S3, the mass ratio of the bentonite to the silane coupling agent KH570 is 8 - 12:2 - 3.

[0032] Further, in step S4, the mass ratio of the pretreated bentonite, acrylic acid, and dodecafluoroheptyl methacrylate is 10 - 15:5 - 10:4 - 8.

[0033] The present invention has the following beneficial effects:

[0034] 1. First, the present invention pre-treats bentonite with a silane coupling agent, introducing a silane coupling agent containing a double bond onto the bentonite to obtain pre-treated bentonite, and then mixes it with acrylic acid and dodecafluoroheptyl methacrylate, and carries out a polymerization reaction under the action of an initiator to introduce acrylic acid segments and dodecafluoroheptyl methacrylate into the modified bentonite. The fluorine-containing segments of the modified bentonite can improve the hydrophobicity and compatibility of the components; Secondly, the present invention uses the product of butyl acrylate polymerization as the core structure, and then uses dodecafluoroheptyl methacrylate to carry out a polymerization reaction with butyl acrylate, methyl methacrylate and 2-hydroxyethyl acrylate as the shell structure to obtain a fluorocarbon emulsion with a core-shell structure. Since the fluorocarbon emulsion and the modified bentonite have similar fluorine-containing segments, the fluorine-containing segments of the two are intertwined and crosslinked, promoting the arrangement between molecular chains to be more compact, forming a stable three-dimensional crosslinked spatial network structure; In addition, the present invention also uses the silane coupling agent KH560 to modify colored sand, thereby introducing epoxy groups, enabling the modified colored sand to crosslink with the hydroxyl and carboxyl groups on the fluorocarbon emulsion and the modified bentonite, improving the binding force between the components, further improving the strength of the paint film, and enhancing the weather resistance, stain resistance and service life of the real stone paint.

[0035] 2. The real stone paint of the present invention has the advantages of self-filming at low temperature, rain mark resistance, fast initial drying speed, etc., has good application prospects, and can solve the construction problems in low-temperature and high-humidity areas; moreover, the present invention does not require additional addition of film-forming aids to assist the emulsion in film formation, which helps to improve the strength of the paint film and accelerate its drying speed. On the other hand, the product of the present invention has a lower odor and better environmental protection performance compared with existing real stone paint products. Specific Embodiments

[0036] In order to more clearly illustrate the technical solutions of the present invention, the following examples are listed. The raw materials, reactions and post-treatment means appearing in the examples are all common raw materials on the market and technical means well-known to those skilled in the art, unless otherwise specified.

[0037] The terms "preferred", "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain cases. However, in the same or other cases, other embodiments may also be preferred. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present invention.

[0038] It should be understood that, except in any operating instance or otherwise indicated, all numbers expressing quantities of ingredients, for example, used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that vary depending upon the desired properties sought to be obtained by the present invention.

[0039] Low-temperature self-forming film emulsion, Badfu RS9920.

[0040] Bentonite, sodium-based bentonite, 2000 mesh, LingShou County DongYan Mineral Products Co., Ltd.

[0041] The colored sand is a mixture of colored sand with mesh numbers of 40 - 80 mesh and 80 - 120 mesh, among which the colored sand with 40 - 80 mesh accounts for 27% of the total weight of the colored sand, Hubei Jinzhuan Mineral Products Co., Ltd.

[0042] Cellulose, hydroxyethyl cellulose, Ashland 250HHBR.

[0043] Thickener, polyurethane thickener, French Gota Coapur 817W.

[0044] Antifreeze, ethylene glycol.

[0045] Defoamer, mineral oil defoamer, British Wellman Company Defoamer 1816.

[0046] Bactericide, compound of nitrogen and sulfur heterocyclic compounds and formaldehyde, THOR Company EG-CLF.

[0047] pH regulator, aqueous silicone solution, Wacker BS168.

[0048] Polyvinyl alcohol, sigma company 360627, molecular weight 9000 - 10000.

[0049] Example 1

[0050] A kind of low-temperature self-forming film real stone paint without film-forming aid, the low-temperature self-forming film real stone paint without film-forming aid comprises the following components in parts by mass:

[0051]

[0052] The preparation method of the above-mentioned low-temperature self-forming film real stone paint without film-forming aid is as follows:

[0053] S1. Mix 0.5 part of ammonium persulfate, 0.2 part of polyvinyl alcohol, 4 parts of sodium dodecylbenzenesulfonate, 0.4 part of sodium bicarbonate and 60 parts of deionized water evenly, heat to 50 °C, raise the temperature to 70 °C after 10 min, add 26 parts of butyl acrylate after stirring, and heat and react at 80 °C for 2 h to obtain a seed emulsion;

[0054] S2. Mix 0.1 part of ammonium persulfate, 40 parts of methyl methacrylate, 20 parts of 2-hydroxyethyl acrylate, 30 parts of butyl acrylate, 1 part of dodecafluoroheptyl methacrylate and 90 parts of deionized water evenly, then add them into the seed emulsion, heat and react at 80 °C for 2 h, cool to room temperature, and filter to obtain the fluorocarbon emulsion;

[0055] S3. Soak 8 parts of bentonite in 150 parts of 80 wt% ethanol aqueous solution, ultrasonically disperse for 30 min, then add 2 parts of silane coupling agent KH570, heat and react at 40 °C for 3 h, filter and wash, and obtain the pretreated bentonite after drying;

[0056] S4. Under the protection of nitrogen, disperse 10 parts of the pretreated bentonite in 150 parts of deionized water, add 5 parts of acrylic acid, 4 parts of dodecafluoroheptyl methacrylate and 0.5 part of potassium persulfate, heat and react at 80 °C for 3 h, filter and wash, and obtain the modified bentonite after drying;

[0057] S5. Under the protection of nitrogen, mix 5 parts of colored sand and 100 parts of absolute ethanol evenly, then add 1 part of silane coupling agent KH560, heat to 60 °C and react for 4 h, wash, filter and dry to obtain the modified colored sand;

[0058] S6. According to the above mass parts, blend the fluorocarbon emulsion, the modified bentonite and the modified colored sand with other components to obtain the film-forming aid-free low-temperature self-film-forming real stone paint.

[0059] Example 2

[0060] A film-forming aid-free low-temperature self-film-forming real stone paint, and the film-forming aid-free low-temperature self-film-forming real stone paint comprises the following components in mass parts:

[0061]

[0062] The preparation method of the above film-forming aid-free low-temperature self-film-forming real stone paint is as follows:

[0063] S1. Mix 0.5 part of ammonium persulfate, 0.2 part of polyvinyl alcohol, 4 parts of sodium dodecylbenzenesulfonate, 0.4 part of sodium bicarbonate and 60 parts of deionized water evenly, heat to 50 °C, raise the temperature to 70 °C after 10 min, stir and add 26 parts of butyl acrylate, heat and react at 80 °C for 2 h to obtain the seed emulsion;

[0064] S2. Mix 0.1 part of ammonium persulfate, 40 parts of methyl methacrylate, 20 parts of 2-hydroxyethyl acrylate, 30 parts of butyl acrylate, 1 part of dodecafluoroheptyl methacrylate and 90 parts of deionized water evenly, then add them into the seed emulsion, heat and react at 80 °C for 2 h, cool to room temperature, and filter to obtain the fluorocarbon emulsion;

[0065] S3. Soak 8 parts of bentonite in 150 parts of 80 wt% ethanol aqueous solution, ultrasonically disperse for 30 min, then add 2 parts of silane coupling agent KH570, heat and react at 40 °C for 3 h, filter, wash, and dry to obtain pretreated bentonite;

[0066] S4. Under the protection of nitrogen, disperse 10 parts of pretreated bentonite in 150 parts of deionized water, add 5 parts of acrylic acid, 4 parts of dodecafluoroheptyl methacrylate and 0.5 part of potassium persulfate, heat and react at 80 °C for 3 h, filter, wash, and dry to obtain modified bentonite;

[0067] S5. Under the protection of nitrogen, mix 5 parts of colored sand and 100 parts of absolute ethanol evenly, then add 1 part of silane coupling agent KH560, heat to 60 °C and react for 4 h, wash, filter, and dry to obtain modified colored sand;

[0068] S6. According to the above mass parts, blend fluorocarbon emulsion, modified bentonite and modified colored sand with other components to obtain a low-temperature self-forming real stone paint without film-forming aids.

[0069] Example 3

[0070] A low-temperature self-forming real stone paint without film-forming aids, which comprises the following components in mass parts:

[0071]

[0072] The preparation method of the above low-temperature self-forming real stone paint without film-forming aids is as follows:

[0073] S1. Mix 0.5 part of ammonium persulfate, 0.2 part of polyvinyl alcohol, 4 parts of sodium dodecylbenzenesulfonate, 0.4 part of sodium bicarbonate and 60 parts of deionized water evenly, heat to 50 °C, raise the temperature to 70 °C after 10 min, stir and add 26 parts of butyl acrylate, heat and react at 80 °C for 2 h to obtain a seed emulsion;

[0074] S2. Mix 0.1 part of ammonium persulfate, 40 parts of methyl methacrylate, 20 parts of 2-hydroxyethyl acrylate, 30 parts of butyl acrylate and 1 part of dodecafluoroheptyl methacrylate and 90 parts of deionized water evenly, then add it to the seed emulsion, heat and react at 80 °C for 2 h, cool to room temperature, and filter to obtain a fluorocarbon emulsion;

[0075] S3. Soak 8 parts of bentonite in 150 parts of 80 wt% ethanol aqueous solution, ultrasonically disperse for 30 min, then add 2 parts of silane coupling agent KH570, heat and react at 40 °C for 3 h, filter, wash, and dry to obtain pretreated bentonite;

[0076] S4. Under the protection of nitrogen, disperse 10 parts of pretreated bentonite in 150 parts of deionized water, add 5 parts of acrylic acid, 4 parts of dodecafluorooctyl methacrylate and 0.5 part of potassium persulfate, heat and react at 80 °C for 3 h, filter, wash, and dry to obtain modified bentonite;

[0077] S5. Under the protection of nitrogen, mix 5 parts of colored sand and 100 parts of absolute ethanol evenly, then add 1 part of silane coupling agent KH560, heat to 60 °C and react for 4 h, wash, filter, and dry to obtain modified colored sand;

[0078] S6. According to the above mass parts, blend fluorocarbon emulsion, modified bentonite and modified colored sand with other components to obtain a low-temperature self-forming real stone paint without film-forming aids.

[0079] Comparative Example 1

[0080] The difference between this comparative example and Example 1 is that: replace the fluorocarbon emulsion with an equal mass of low-temperature self-forming emulsion (Badfu RS9920), and other components and preparation methods are the same.

[0081] Comparative Example 2

[0082] The difference between this comparative example and Example 1 is that: remove step S4, that is, only modify bentonite with silane coupling agent KH570, and other components and preparation methods are the same.

[0083] Test Example 1

[0084] Perform performance tests on the real stone paints prepared in Examples 1-3 and Comparative Examples 1-2.

[0085] Test method:

[0086] Conduct performance tests on workability, film appearance, adhesion strength and low-temperature stability in accordance with the JG / T24-2018 standard.

[0087] Drying time (surface dry) test: According to the provisions of Method B for surface dry in GB / T 1728-1979 "Determination of Drying Time of Paint Film and Putty Film", test the drying time (surface dry) of the real stone paint, and modify the constant temperature and humidity drying conditions to 5 °C and 85% humidity.

[0088] Rain mark resistance performance test: Spray the real stone paint on a calcium silicate board of 300 mm × 200 mm × 10 mm using a real stone paint spray gun. The weight of the real stone paint sprayed on each board is about 180 ± 5 g. Place the sprayed test board in a programmable constant temperature and humidity chamber at 5 °C and 85% humidity for 24 h. Then take out the test board and stand it upright under the faucet, slowly drip tap water onto the film surface, drip for 6 h at a drip rate of 1 drop per second. After the dripping is completed, take out the test board and stand it upright on the table, and wait for the paint board to dry naturally. Observe the rain mark situation on the film surface.

[0089] The environmental protection performance was detected in accordance with the limit standards for harmful substances in architectural wall coatings GB 18582-2020.

[0090] The test results are shown in Table 1-2.

[0091] Table 1 Performance test results of the real stone paints of Examples 1-3 and Comparative Examples 1-2

[0092]

[0093] Table 2 Environmental protection performance test results of the real stone paints of Examples 1-3 and Comparative Examples 1-2

[0094]

[0095]

[0096] Based on the above test results, it can be seen that the film-forming assistant-free low-temperature self-film-forming real stone paint of the present invention has low-temperature self-film-forming (below 5°C), a fast film drying speed, and the product has excellent rain mark resistance, workability, and environmental protection. Each performance can meet the JG / T24-2018 standard, and each environmental protection performance parameter can pass GB 18582-2020. In Examples 1-3, modified bentonite, fluorocarbon emulsion, and modified colored sand were added, making the product have superior rain mark resistance, good hydrophobicity, and a lotus leaf hydrophobic effect on the film surface. Rainwater is not easily penetrated into the coating, and water droplets are formed on the film surface and roll down, improving the rain mark resistance of the film. Moreover, it can form a film normally at low temperature, has a high bonding strength, does not require the addition of a film-forming assistant, and has a very low VOC.

[0097] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

[0098] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A low-temperature self-filming real stone paint without film-forming aid, characterized in that: The low-temperature self-filming real stone paint without film-forming aids comprises the following components in parts by mass: Wherein, the modified bentonite is bentonite modified by dodecafluoroheptyl methacrylate; The fluorocarbon emulsion is an acrylic emulsion with a fluorine core-shell structure; The modified colored sand is colored sand modified by a silane coupling agent.

2. The low-temperature self-filming true stone paint without film-forming aid according to claim 1, characterized in that: The cellulose is selected from one or more of hydroxyethyl cellulose and hydroxymethyl cellulose.

3. The low-temperature self-filming true stone paint without film-forming aid according to claim 1, characterized in that: The auxiliary agent is selected from one or more of a defoamer, a bactericide, a pH regulator, an antifreeze agent, and a thickener.

4. The low-temperature self-filming true stone paint without film-forming aid according to claim 3, characterized in that: The bactericide is one or more of isothiazolinones, benzisothiazolines and s-triazines.

5. The low-temperature self-filming true stone paint without film-forming aid according to claim 1, characterized in that: The pH regulator is selected from one or more of an organic alkaline regulator and an organic silicon regulator.

6. The low-temperature self-filming true stone paint without film-forming aid according to claim 1, characterized in that: The thickener is selected from one or more of an alkali swelling thickener and a polyurethane thickener.

7. The method for preparing the low-temperature self-filming true stone paint without film-forming aids according to any one of claims 1 to 6, characterized in that: The steps include: S1. ammonium persulfate, polyvinyl alcohol, sodium dodecylbenzene sulfonate and sodium bicarbonate are added to a solvent, and then butyl acrylate is added and heated to react to obtain a seed emulsion; S2. ammonium persulfate, methyl methacrylate, hydroxyethyl acrylate, butyl acrylate and dodecafluoroheptyl methacrylate were added to the solvent, mixed evenly, and then added to the seed emulsion, heated to react, and obtained a fluorocarbon emulsion; S3. The bentonite was immersed in a solvent, ultrasonically dispersed, and then a silane coupling agent KH570 was added, and the reaction was heated to obtain a pretreated bentonite; S4. Under the protection of an inert gas, the pretreated bentonite is dispersed in a solvent, dodecafluoroheptyl methacrylate, acrylic acid and an initiator are added, and the reaction is heated to obtain a modified bentonite; S5. Under the protection of an inert gas, the colored sand is added to a solvent, and then a silane coupling agent KH560 is added, and the reaction is heated to obtain a modified colored sand; S6. Blending the fluorocarbon emulsion, modified bentonite and modified colored sand with other ingredients to obtain a low-temperature self-film-forming real stone paint without film-forming aids.

8. The method for preparing the low-temperature self-filming true stone paint without film-forming aid according to claim 7, characterized in that: In step S3, the mass ratio of the bentonite to the silane coupling agent KH570 is 8-12:2-3.

9. The method for preparing the low-temperature self-filming true stone paint without film-forming aid according to claim 7, characterized in that: In step S4, the mass ratio of pretreated bentonite, acrylic acid, and dodecafluoroheptyl methacrylate is 10-15:5-10:4-8.

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