A washable wall coating and its preparation method

Abstract

This invention discloses a washable wall coating and its preparation method, relating to the technical field of wall coatings. A washable wall coating comprises a modified styrene-acrylic emulsion, functional additives, pigments and fillers, protective additives, and water. The modified styrene-acrylic emulsion is synthesized from functionalized POSS with a functionality of 4-8 as a functional monomer. The functional additives include at least a dispersant and a film-forming aid. The dispersant is a fatty acid polyoxyethylene ester dispersant, and the film-forming aid includes one or more combinations of alcohol ester film-forming aids and ether ester film-forming aids. Through the technical solution of this application, while ensuring the wall coating has high environmental friendliness and low VOC content, it also possesses excellent washability, good application and film-forming properties, scratch resistance, and water resistance.

Description

Technical Field

[0001] This invention relates to the field of wall coatings, and in particular to a washable wall coating and its preparation method. Background Technology

[0002] As an important material for interior decoration, wall paint's performance directly affects the quality of living spaces and subsequent maintenance costs. With consumers increasingly demanding durability and health and safety in their living environments, wall paints not only need basic decorative functions but also must meet higher standards in terms of environmental friendliness and durability. Among these, washability is a core mechanical performance indicator for measuring the lifespan and quality grade of wall paint, and it directly relates to whether the wall surface can withstand repeated wiping and washing without revealing the substrate or powdering.

[0003] In existing technologies, the main approaches to improving the washability of wall coatings include the following: enhancing the cohesiveness of the wall coating by increasing the crosslinking degree of the emulsion polymer, or introducing more inorganic nanoparticles such as nano-silica and nano-calcium carbonate to improve the surface hardness and density of the wall paint film, or introducing epoxy resin or organosilicon to modify the emulsion to improve the hardness of the paint film.

[0004] However, the aforementioned technologies generally have limitations in implementation. First, simply increasing the crosslinking degree of the emulsion can easily lead to an increase in the minimum film-forming temperature of the wall coating, resulting in poorer film-forming properties at low or room temperatures, directly affecting the workability tolerance and film integrity. Second, the dispersion stability of inorganic nanoparticles in organic film-forming systems is difficult to control, easily leading to agglomeration and stress concentration points, which limits the improvement of the film's washability and may even cause microcracks, affecting its service life. Furthermore, while some solutions that modify the emulsion by introducing epoxy resin and silicone increase hardness, they often require the simultaneous introduction of a large number of film-forming aids to balance workability, such as alkylphenol polyoxyethylene ether surfactants. However, alkylphenol polyoxyethylene ether surfactants have long been included in the national limited control scope due to their environmental pollution, making it difficult to meet high environmental protection standards.

[0005] Therefore, developing a wall coating that combines excellent washability, high environmental friendliness, and good film-forming properties to address the shortcomings of existing technologies is of great practical significance for promoting technological progress in this field and meeting the high-quality demands of the interior decoration market. Summary of the Invention

[0006] In order to improve the washability of wall coatings while ensuring their high environmental friendliness and good workability, this application provides a washable wall coating and its preparation method.

[0007] Firstly, the washable wall coating provided in this application adopts the following technical solution: A washable wall coating, comprising the following raw materials by weight percentage based on the total mass of the wall coating: Modified styrene-acrylic emulsion 20-28%, functional additives 5-8%, pigments and fillers 35-40%, protective additives 0.5-0.8%, balance is water; The raw materials for preparing the modified styrene-acrylic emulsion include functionalized POSS, wherein the functional groups of the functionalized POSS are one or more of alkenyl, epoxy and acryloyloxy groups, and the functionality is 4-8. The functional additives include at least a dispersant and a film-forming aid, wherein the dispersant is a fatty acid polyoxyethylene ester dispersant, and the film-forming aid includes one or a combination of two of alcohol ester film-forming aids and ether ester film-forming aids.

[0008] By adopting the above technical solution, modified styrene-acrylic emulsions are prepared by introducing multifunctionalized POSS, and this emulsion is used as the main film-forming substance in wall coatings. Combined with fatty acid polyoxyethylene ester dispersants and alcohol or ether ester film-forming aids, the use of alkylphenol polyoxyethylene ether surfactants in wall coatings can be effectively reduced, ensuring the wall coatings have good environmental friendliness and low VOC content. Simultaneously, through the crosslinking characteristics of multifunctionalized POSS, crosslinking centers can be formed in the coating, creating a dense three-dimensional crosslinked network structure. This significantly improves the surface hardness and adhesion of the coating, thus enabling the wall coating to possess excellent washability, good film-forming properties, scratch resistance, and water resistance.

[0009] Optionally, the modified styrene-acrylic emulsion comprises the following raw materials by mass percentage: Soft monomers 28-35%, hard monomers 16-20%, functional monomers 5-8%, emulsifiers 5-8%, initiators 1.5-3%, balance is water; The functional monomer is a composition of functionalized POSS and acrylic acid, and the mass ratio of the functionalized POSS to the acrylic acid is 1:(1-4).

[0010] By adopting the above technical solution and optimizing the ratio and composition of each monomer, on the one hand, functionalized POSS and acrylic acid can synergistically form stable crosslinking centers during polymerization, significantly improving the film density and cohesiveness of the modified styrene-acrylic emulsion. On the other hand, it can prevent the degradation of the workability and later film-forming properties of the modified styrene-acrylic emulsion due to the large number of overall hard segments or functional monomers. This is conducive to balancing the workability and film-forming properties of the emulsion while greatly improving the scrub resistance and surface hardness of the wall coating, reducing the introduction of subsequent surfactants such as alkylphenol polyoxyethylene ethers, and ensuring the environmental friendliness of the coating.

[0011] Optionally, the soft monomer is a composition of butyl acrylate, isooctyl acrylate and isodecanyl acrylate, and the mass ratio of butyl acrylate, isooctyl acrylate and isodecanyl acrylate is 1:(0.7-1):(0.1-0.3).

[0012] The hard monomer is a composition of styrene and methyl methacrylate, and the mass ratio of styrene to methyl methacrylate is 1:(1.5-3).

[0013] By adopting the above technical solution, the modified styrene-acrylic emulsion can be endowed with a suitable balance of flexibility and rigidity. At the same time, the overall steric hindrance can be adjusted so that the functionalized POSS and acrylic acid can stably participate in the reaction and form a uniform and dense cross-linked network, which is conducive to achieving a balance of rigidity and toughness in wall coatings.

[0014] Optionally, the functionalized POSS is tetraglycidyl etheroxypropyl-tetraisooctyl POSS, and the functionalized POSS accounts for 2-4% of the total mass of the raw materials of the modified styrene-acrylic emulsion.

[0015] By adopting the above technical solution, the four-functionalized POSS can fully participate in the reaction as a crosslinking center and form a dense network. At the same time, it can prevent the eight-functionalized POSS from generating excessive crosslinking sites or causing local density to be too high due to partial aggregation, which would lead to defect sites in the subsequent coating. This is beneficial to ensure that the wall coating has excellent and uniform scrub resistance while maintaining good overall surface performance.

[0016] Optionally, the preparation method of the modified styrene-acrylic emulsion includes the following steps: A1. By weight, mix 15-25% emulsifier and 45-55% water to obtain the base liquid; mix soft monomer, hard monomer, 55-65% emulsifier and 15-25% water to obtain the pre-emulsified monomer liquid; mix functional monomer, the remaining emulsifier and 15-25% water to obtain the pre-emulsified functional liquid; mix initiator and the remaining water to obtain the initiator liquid. A2. By weight, heat the base liquid to 80-83℃, add 10-15% initiator, stir evenly, and then slowly add the pre-emulsified monomer liquid, functional monomer liquid and 80-85% initiator liquid. Continue stirring the reaction and keep the temperature within 80-85℃. The addition should be completed within 3 hours, and the pre-emulsified monomer liquid, pre-emulsified functional liquid and 80-85% initiator liquid should be added simultaneously according to the mass ratio. A3. After the addition is complete, continue stirring for 10-15 minutes, add the remaining initiator solution, and heat to 88-90℃. Keep warm and continue stirring for 60-90 minutes. Adjust and control the pH value at 7-8 during the reaction to obtain the emulsion matrix. After taking a sample from the emulsion matrix and smelling it until there is no obvious irritating odor, cool it down to below 40℃ and filter it to obtain the modified styrene-acrylic emulsion.

[0017] By adopting the above technical solution, it is beneficial to improve the conversion rate of copolymerization reaction between functional monomers and other monomers, while reducing the enrichment of residual unreacted small molecule monomer byproducts, thereby reducing the irritating odor and VOC precursors in modified styrene-acrylic emulsions.

[0018] Optionally, the functional additives may further include defoamers, wetting agents, thickeners, solubilizers, and leveling agents, wherein the defoamers include front-end defoamers and back-end defoamers.

[0019] The defoamer in the pre-process is a defoamer added in the early stage of the preparation process. It is used to suppress and eliminate a large number of bubbles generated by mechanical shearing and the surface activity of wetting agents during the high-speed dispersion or grinding of pigments, fillers and other powder substances, so as to ensure the uniformity and fineness of the slurry.

[0020] The defoamer mentioned above is added in the later stages of the preparation process. It is used to eliminate newly generated or residual micro-bubbles during the addition of components such as emulsions, leveling agents, and protective additives, as well as during subsequent low-speed stirring, to avoid defects such as pinholes and craters in the finished paint film and to improve the application performance of the coating.

[0021] By adopting the above technical solutions, it is beneficial to improve the relevant performance of wall coatings during the preparation and construction process, and ensure that the wall coatings have excellent construction performance and coating appearance, and prevent defects such as bubbles and sagging from affecting the washability and decorative effect of the coating.

[0022] Optionally, the film-forming aid is a composition of hexadecyl alcohol ester and propylene glycol methyl ether propionate, and the mass ratio of the hexadecyl alcohol ester to the propylene glycol methyl ether propionate is (2.25-5.5):1.

[0023] By adopting the above technical solution, compared with using dodecyl alcohol ester or propylene glycol methyl ether propionate alone, the compounded film-forming aid can not only significantly reduce the VOC content of wall coatings, but also effectively shorten the surface drying time of the coating and maintain a high surface hardness. It overcomes the defects of single ether ester film-forming aids that lead to a decrease in surface hardness and a significant increase in VOC content, and is conducive to balancing environmental protection and good mechanical properties.

[0024] Optionally, the pigments and fillers include at least calcium carbonate and titanium dioxide, and also include one or more of wollastonite, talc and kaolin.

[0025] By adopting the above technical solutions, it is beneficial to control the overall raw material cost while ensuring excellent washability, high surface hardness, and good film-forming properties of wall coatings. Specifically, when calcium carbonate, titanium dioxide, and kaolin are used as pigments and fillers, the lamellar structure of kaolin can enhance the coating's impermeability and abrasion resistance, achieving the best balance between comprehensive performance and economic benefits. Using talc in combination with calcium carbonate and titanium dioxide improves the workability and leveling properties of the wall coating and absorbs expansion and contraction stress in the coating, preventing stress-induced cracking. Using wollastonite in combination with calcium carbonate and titanium dioxide helps to shorten the surface drying time of the coating to a certain extent, while appropriately increasing the initial hardness of the coating.

[0026] Optionally, the protective additive includes a preservative and a mildew inhibitor, and the mass ratio of the preservative to the mildew inhibitor is (1-1.5):1.

[0027] By adopting the above technical solutions, wall coatings can be endowed with long-term and stable antibacterial and anti-mildew capabilities, which helps to inhibit the spoilage, mold growth or degradation of wall coatings caused by microbial growth during storage and use, and helps to extend the service life of wall coatings.

[0028] Secondly, the method for preparing a washable wall coating provided in this application adopts the following technical solution: A method for preparing a washable wall coating includes the following steps: S1. Based on the mass fraction of each raw material, add 70-75% water to the dispersion tank and start stirring at a stirring speed of 400-600 r / min. While stirring, add the dispersant, the pre-stage defoamer and the wetting agent in sequence, and stir evenly. Then add the film-forming aid and the cosolvent in sequence, and stir evenly. Then slowly add the thickener and continue stirring until the system is obviously thickened and forms a semi-gel slurry to obtain the first slurry. S2. Maintain the stirring speed and add pigments and fillers to the first slurry. After adding, scrape the sides of the dispersion tank clean and rinse the sides of the tank and the stirring shaft with water to ensure that all pigments and fillers are fully mixed into the system. Increase the stirring speed to 1200-1500 r / min and maintain high-speed dispersion for 25-30 min. After the dispersion is completed, take a sample to test the fineness of the slurry. When the fineness of the sampled slurry is ≤50μm, the second slurry is obtained. S3. Reduce the stirring speed to 600-800 r / min, and add 15-20% water, modified styrene-acrylic emulsion, downstream defoamer, protective agent and leveling agent to the second slurry in sequence. After the addition is completed, maintain the stirring speed to disperse for 5-10 minutes. Use the remaining water to rinse the tank side and stirring shaft to ensure that all raw materials are fully mixed into the system and stirred evenly to obtain the third slurry. S4. Based on the total mass of the third slurry in the tank, release 5-10% of the third slurry through the discharge valve, then pour it back into the dispersion tank, rinse with the remaining water, continue dispersion, filter and discharge to obtain the washable wall coating.

[0029] By adopting the above technical solutions, it is beneficial to ensure that each component is evenly dispersed in the coating and reduce the risk of agglomeration. It is also beneficial to prevent the damage of modified styrene-acrylic emulsion by high shear force. Secondly, the staged addition of defoamer can effectively suppress the source of air bubbles in different process stages and ensure that the air bubbles in each stage of the slurry are fully removed. This is conducive to obtaining high-quality wall coatings with qualified fineness, high density, good appearance smoothness and high scrub resistance.

[0030] In summary, the technical solution of this application has at least one of the following beneficial effects: 1. By introducing a multifunctionalized POSS to prepare a modified styrene-acrylic emulsion, and using it as the main film-forming substance for wall coatings, combined with fatty acid polyoxyethylene ester dispersants and alcohol ester or ether ester film-forming aids, the wall coating can be ensured to have good environmental protection and low VOC content. Moreover, it can form a dense three-dimensional cross-linked network structure, which significantly improves the surface hardness and adhesion of the coating. This is conducive to enabling the wall coating to have excellent washability, good construction film-forming properties, scratch resistance and water resistance.

[0031] 2. By using tetrafunctional POSS and acrylic acid as functional monomers for modifying styrene-acrylic emulsion, it is possible to prevent the generation of excessive crosslinking sites by eight-functional POSS, or the formation of defect sites in subsequent coatings due to localized high density caused by partial agglomeration. This helps to maintain good overall surface properties while ensuring that the wall coating has excellent and uniform scrub resistance. Detailed Implementation

[0032] The present application will be further described in detail below with reference to preparation examples, embodiments and comparative examples.

[0033] All the functional POS systems were purchased from Guangzhou Yixin Technology.

[0034] Both dodecyl alcohol ester and hexadecyl alcohol ester were purchased from Runtian Chemical, with the dodecyl alcohol ester using the grade RTC-12 and the hexadecyl alcohol ester using the grade RTC-16.

[0035] The calcium carbonate was purchased from Xufeng Powder, and the grade used was NC-90A.

[0036] The titanium dioxide was purchased from Xinzhong Titanium, specifically rutile titanium dioxide, grade R369.

[0037] The kaolin was purchased from Sanxin calcined kaolin, and the grade used was SX 80A.

[0038] The talc powder was purchased from Xufeng Powder, and the grade used was BHS-818.

[0039] The wollastonite was purchased from Siyuan Mining, and their ultrafine wollastonite powder for paints and coatings was selected. Preparation Example

[0040]

Preparation Example 1

[0041] In this embodiment, the soft monomers include 12.5 kg of butyl acrylate, 16.25 kg of isooctyl acrylate, and 1.25 kg of isodecanyl acrylate. The hard monomers include 4 kg of styrene and 12 kg of methyl methacrylate.

[0042] In this embodiment, the functional monomer includes 2 kg of functionalized POSS and 6 kg of acrylic acid, wherein the functionalized POSS is specifically selected as octaacryloyloxypropyl POSS, with the brand name Ecotion POSS 1013.

[0043] In this embodiment, the emulsifier was purchased from Nanjing Baiju Technology, and the brand name was EP-10. The initiator was potassium persulfate.

[0044] A method for preparing a modified styrene-acrylic emulsion includes the following steps: A1. By weight, mix 20% emulsifier and 50% water to obtain the base liquid; mix soft monomer, hard monomer, 60% emulsifier and 20% water to obtain the pre-emulsified monomer liquid; mix functionalized monomer, 20% emulsifier and 20% water to obtain the pre-emulsified functional liquid; mix initiator and the remaining water to obtain the initiator liquid. A2. By mass, heat the base liquid to 83°C, add 10% initiator, stir evenly, and slowly add the pre-emulsified monomer liquid, functional monomer liquid and 85% initiator liquid. Continue stirring the reaction and keep the temperature within 80-85°C. The addition should be completed within 3 hours, and the pre-emulsified monomer liquid, pre-emulsified functional liquid and 85% initiator liquid should be added simultaneously according to the mass ratio. A3. After the addition is complete, continue stirring and reacting for 15 minutes. Add the remaining initiator solution and heat to 88°C. Keep warm and continue stirring and reacting for 60 minutes. Adjust and control the pH value between 7 and 8 during the reaction to obtain the emulsion matrix. After taking a sample from the emulsion matrix and smelling it until there is no obvious irritating odor, cool it to below 40°C and filter it through nylon cloth to obtain the modified styrene-acrylic emulsion.

[0045]

Preparation Example 2

[0046] In this preparation example, the soft monomers include 13 kg of butyl acrylate, 9.1 kg of isooctyl acrylate, and 3.9 kg of isodecanyl acrylate. The hard monomers include 8 kg of styrene and 12 kg of methyl methacrylate.

[0047] In this preparation example, the functional monomers include 1 kg of functionalized POSS and 4 kg of acrylic acid, wherein the functionalized POSS is specifically selected as octaglycidyl etheroxypropyl POSS, with the brand name Ecotion POSS 101.

[0048]

Preparation Example 3

[0049] In this preparation example, the functionalized POSS specifically used is octavinyl POSS, with the brand name Ecotion POSS 106.

[0050]

Preparation Example 4

[0051] In this preparation example, the functionalized POSS specifically selected is octaglycidyloxypropyl POSS, with the brand name EcotionPOSS 101.

[0052]

Preparation Example 5

[0053] In this preparation example, the functionalized POSS specifically selected is tetraglycidyl oxypropyl-tetraisooctyl POSS, brand name Ecotion POSS 409.

[0054]

Preparation Example 6

[0055] In this preparation example, the functional monomers include 4 kg of functionalized POSS and 4 kg of acrylic acid.

[0056]

Preparation Example 7

[0057] In this preparation example, the functional monomers include 6 kg of functionalized POSS and 2 kg of acrylic acid.

[0058]

Preparation Example 8

[0059] In this preparation example, the functional monomer includes 8 kg of acrylic acid.

[0060]

Preparation Example 9

[0061] In this preparation example, the functionalized POSS specifically selected is monoacryloyloxy-heptaisobutyl POSS, brand name Ecotion POSS 301. Example

[0062]

Example 1

[0063] In this embodiment, the modified styrene-acrylic emulsion was prepared according to [Preparation Example 1].

[0064] In this embodiment, the functional additives include 0.7 kg of dispersant, 2.6 kg of film-forming aid, 1 kg of defoamer, 0.1 kg of wetting agent, 0.25 kg of thickener, 1.2 kg of solubilizer and 0.6 kg of leveling agent.

[0065] The dispersant used is a fatty acid polyoxyethylene ester dispersant from Jiangsu Haian Petrochemical, brand name A-105. The film-forming aid is an alcohol ester film-forming aid, specifically a dodecyl alcohol ester. The defoamer includes 0.6 kg of pre-stage defoamer and 0.4 kg of post-stage defoamer. The pre-stage defoamer is purchased from German company TEGE FOAMEX-810, and the post-stage defoamer is purchased from Sannopco, brand name NOPCO NXZ-K. The wetting agent is purchased from German company TEGE, brand name WET 580 Terra. The thickener is hydroxyethyl cellulose from Korean company Lotte, brand name HECELLOSETM B100K. The co-solvent is ethylene glycol. The leveling agent is an associative thickening and leveling agent from BYK Chemicals, brand name OPTIFLO-L150.

[0066] In this embodiment, the pigment and filler are a composition of calcium carbonate, titanium dioxide and kaolin, specifically including 20 kg of calcium carbonate, 10 kg of titanium dioxide and 5 kg of kaolin.

[0067] In this embodiment, the protective additives include 0.3 kg of preservative and 0.2 kg of fungicide. The preservative was purchased from Shanghai Rigan Chemical Co., Ltd., and the brand name is KS-25; the fungicide was purchased from Troy Chemicals Ltd. in the United States, and the brand name is Polyphase-678.

[0068] A method for preparing a washable wall coating includes the following steps: S1. Based on the mass fraction of each raw material, add 75% water to the dispersion tank and start stirring at a stirring speed of 500 r / min. While stirring, add the dispersant, the pre-stage defoamer and the wetting agent in sequence, and stir evenly. Then add the film-forming aid and the cosolvent in sequence, and stir evenly. Then slowly add the thickener and continue stirring until the system is obviously thickened and forms a semi-gel slurry to obtain the first slurry. S2. Maintain the stirring speed and add pigments and fillers to the first slurry. After the addition is complete, scrape the sides of the dispersion tank clean and rinse the sides of the tank and the stirring shaft with 2% water to ensure that all pigments and fillers are fully mixed into the system. Increase the stirring speed to 1200 r / min and maintain high-speed dispersion for 30 min. After the end, take a sample to test the fineness of the slurry. When the fineness of the sampled slurry is ≤50μm, the second slurry is obtained. S3. Reduce the stirring speed to 600 r / min, and add 20% water, modified styrene-acrylic emulsion, downstream defoamer, protective agent and leveling agent to the second slurry in sequence. After the addition is completed, maintain the stirring speed to disperse for 10 minutes. Use 2% water to rinse the tank side and stirring shaft to ensure that all raw materials are fully mixed into the system and stirred evenly to obtain the third slurry. S4. Based on the total mass of the third slurry in the tank, release 5% of the third slurry through the discharge valve, then pour it back into the dispersion tank, rinse with the remaining water, continue dispersion for 5 minutes, take a sample for testing, and after passing the test, filter and discharge the material to obtain the washable wall coating.

[0069]

Example 2

[0070] In this embodiment, the modified styrene-acrylic emulsion was prepared according to [Preparation Example 2].

[0071] In this embodiment, the functional additives include 1 kg of dispersant, 3 kg of film-forming aid, 1.2 kg of defoamer, 0.2 kg of wetting agent, 0.2 kg of thickener, 1.6 kg of solubilizer and 0.8 kg of leveling agent.

[0072] The film-forming aids include 2.5 kg of alcohol ester film-forming aids and 0.5 kg of ether ester film-forming aids, wherein the alcohol ester film-forming aid is selected from hexadecyl alcohol esters, and the ether ester film-forming aid is selected from propylene glycol methyl ether propionate. The defoamer includes 0.8 kg of pre-defoamer and 0.4 kg of post-defoamer. All other components are the same as in [Example 1].

[0073] In this embodiment, the pigment and filler is a composition of calcium carbonate, titanium dioxide and talc, specifically including 20 kg of calcium carbonate, 12 kg of titanium dioxide and 8 kg of talc.

[0074] In this embodiment, the protective additives include 0.45 kg of preservative and 0.35 kg of mildew inhibitor. The rest is the same as in [Example 1].

[0075] A method for preparing a washable wall coating includes the following steps: S1. Based on the mass fraction of each raw material, add 75% water to the dispersion tank and start stirring at a stirring speed of 600 r / min. While stirring, add the dispersant, the pre-stage defoamer and the wetting agent in sequence, and stir evenly. Then add the film-forming aid and the cosolvent in sequence, and stir evenly. Then slowly add the thickener and continue stirring until the system is obviously thickened and forms a semi-gel slurry to obtain the first slurry. S2. Maintain the stirring speed and add pigments and fillers to the first slurry. After adding, scrape the sides of the dispersion tank clean and rinse the sides of the tank and the stirring shaft with 2% water to ensure that all pigments and fillers are fully mixed into the system. Increase the stirring speed to 1500 r / min and maintain high-speed dispersion for 25 min. After the process, take a sample to test the fineness of the slurry. When the fineness of the sampled slurry is ≤50μm, the second slurry is obtained. S3. Reduce the stirring speed to 800 r / min, and add 20% water, modified styrene-acrylic emulsion, downstream defoamer, protective agent and leveling agent to the second slurry in sequence. After the addition is completed, maintain the stirring speed to disperse for 8 minutes. Use 2% water to rinse the tank side and stirring shaft to ensure that all raw materials are fully mixed into the system and stirred evenly to obtain the third slurry. S4. Based on the total mass of the third slurry in the tank, release 5% of the third slurry through the discharge valve, then pour it back into the dispersion tank, rinse with the remaining water, continue dispersion for 5 minutes, take a sample for testing, and after passing the test, filter and discharge the material to obtain the washable wall coating.

[0076]

Example 3

[0077] In this embodiment, the modified styrene-acrylic emulsion was specifically prepared according to [Preparation Example 3].

[0078]

Example 4

[0079] In this embodiment, the modified styrene-acrylic emulsion was specifically prepared according to [Preparation Example 4].

[0080]

Example 5

[0081] In this embodiment, the modified styrene-acrylic emulsion was specifically prepared according to [Preparation Example 5].

[0082]

Example 6

[0083] In this embodiment, the modified styrene-acrylic emulsion was specifically prepared according to [Preparation Example 6].

[0084]

Example 7

[0085] In this embodiment, the modified styrene-acrylic emulsion was specifically prepared according to [Preparation Example 7].

[0086]

Example 8

[0087] In this embodiment, the film-forming aid does not contain dodecyl alcohol ester, and hexadecyl alcohol ester is used to replace dodecyl alcohol ester in an equal amount, that is, the film-forming aid includes 2.6 kg of hexadecyl alcohol ester.

[0088]

Example 9

[0089] In this embodiment, the film-forming aid does not contain dodecyl alcohol ester, and an ether ester film-forming agent is used to replace the dodecyl alcohol ester in an equal amount. The ether ester film-forming agent is propylene glycol methyl ether propionate, that is, the film-forming aid includes 2.6 kg of propylene glycol methyl ether propionate.

[0090]

Example 10

[0091] In this embodiment, the film-forming aid includes 2.2 kg of alcohol ester film-forming aid and 0.4 kg of ether ester film-forming aid, wherein the alcohol ester film-forming aid is selected from hexadecyl alcohol ester and the ether ester film-forming aid is selected from propylene glycol methyl ether propionate.

[0092]

Example 11

[0093] In this embodiment, the film-forming aid includes 1.8 kg of alcohol ester film-forming aid and 0.8 kg of ether ester film-forming aid, wherein the alcohol ester film-forming aid is selected from hexadecyl alcohol ester and the ether ester film-forming aid is selected from propylene glycol methyl ether propionate.

[0094]

Example 12

[0095] In this embodiment, the pigment and filler is a composition of calcium carbonate, titanium dioxide and talc, specifically including 20 kg of calcium carbonate, 10 kg of titanium dioxide and 5 kg of talc.

[0096]

Example 13

[0097] In this embodiment, the pigment and filler are a composition of calcium carbonate, titanium dioxide and wollastonite, specifically including 20 kg of calcium carbonate, 10 kg of titanium dioxide and 5 kg of wollastonite. Comparative Example

[0098] Comparative Example 1 A wall coating, which differs from [Example 1] in that it uses a different modified styrene-acrylic emulsion.

[0099] In this embodiment, the modified styrene-acrylic emulsion was prepared according to [Preparation Example 8].

[0100] Comparative Example 2 A wall coating, which differs from [Example 1] in that it uses a different modified styrene-acrylic emulsion.

[0101] In this comparative example, the modified styrene-acrylic emulsion was prepared according to [Preparation Example 9]. Performance testing

[0102] Sample preparation: Refer to the formulations and preparation methods of each embodiment and comparative example to prepare the corresponding wall paint samples to be tested, and prepare the corresponding test panels according to each test standard.

[0103] 1. Scrub Resistance Test: The test shall be conducted in accordance with GB / T 9266-2009 Determination of Scrub Resistance of Architectural Coatings. Two test panels shall be used for the test. The specified number of scrubs shall be 6000. If the coating of at least one of the two test panels is not damaged to the point of exposing the substrate, it shall be recorded as "≥6000 times". If both test panels are scrubbed to the point of just exposing the substrate, and the number of scrubs is less than the specified number of scrubs, the result of the test panel with the higher number of scrubs shall be reported, with 100 times as the minimum reporting unit.

[0104] 2. Hardness of paint film: The test shall be conducted in accordance with GB / T 6739-2006 Determination of hardness of paint film by pencil method, and the test results of each sample shall be recorded.

[0105] 3. Water resistance test: The test shall be conducted in accordance with GB / T 1733-93 Test method for water resistance of paint film. Three test panels shall be used for the method A test. The water temperature shall be 25℃ and the soaking time shall be 72h. The condition after soaking shall be tested according to the standard requirements. If at least two of the three test panels meet the requirements, the test panel shall be "qualified". If at least two test panels show obvious deterioration such as loss of gloss, discoloration, blistering, peeling, or rusting, the condition shall be recorded.

[0106] 4. Film-forming properties: The test shall be conducted in accordance with GB / T 1728-2020 Test method for drying time of paint film and putty film. The surface drying time shall be tested according to method B. The ambient temperature shall be set at 20℃. Touch the surface every 30 minutes. If the surface feels slightly sticky but no paint or putty is left on the finger, it shall be considered dry. Record the time of touch.

[0107] 5. Hazardous Substance Testing: Testing shall be conducted in accordance with GB 18582-2020 Limits of Hazardous Substances in Building Wall Coatings. Specifically, for interior wall coatings, the VOC content (g / L) and the total content of alkylphenol polyoxyethylene ether (APEO) shall be determined (limited to octylphenol polyoxyethylene ether (OPEO)). n EO) and nonylphenol polyoxyethylene ether (NP) n EO), n=2-16) / (mg / kg), record the actual data detected by each method. If the actual content in the sample is lower than the detection limit of this method, record "not detected".

[0108] Table 1. Partial performance test data of wall coatings

[0109] Based on Example 1 and Comparative Examples 1-2, and the data in Table 1, it can be seen that by using highly functionalized POSS and acrylic acid as functional monomers to prepare a modified styrene-acrylic emulsion, and then combining it with functional additives containing non-alkylphenol polyoxyethylene ether dispersants and specific film-forming aids, a wall coating with excellent washability, low VOC content, high environmental friendliness, and good construction and film-forming properties can be obtained. Moreover, the resulting coating has high surface hardness and good water resistance, which can effectively improve the overall performance of the wall coating.

[0110] As can be seen from the comparison of Example 1 and Comparative Example 1 and their performance test data, when all the functionalized POSS in the modified styrene-acrylic emulsion in Example 1 was replaced with acrylic acid, not only did the washability of the resulting wall coating decrease significantly, but its surface hardness, water resistance, surface drying time, and VOC content also deteriorated to some extent. The main reason is that the functional monomers account for a high proportion in the modified styrene-acrylic emulsion. When functionalized POSS and acrylic acid work together as functional monomers, on the one hand, functionalized POSS can form crosslinking centers during polymerization and promote the formation of a dense crosslinking network in the coating. Under the synergistic effect of acrylic acid, the washability, surface hardness, and adhesion of the wall coating are improved. On the other hand, the hydrophobic siloxane core of functionalized POSS can effectively balance the hydrophilicity of acrylic acid, reducing the hydrophilic degradation and increased surface drying time caused by excessive acrylic acid. Furthermore, when only acrylic acid is used as the functional monomer, the high proportion of acrylic acid monomer not only makes it difficult to form a stable crosslinking network as a crosslinking center, but also because acrylic acid itself contains certain volatile small molecule components. Additionally, a large amount of volatile neutralizing agent needs to be added subsequently to neutralize these components. This easily leads to insufficient crosslinking density in the coating, increased hydrophilicity, and increased VOC content in the coating, resulting in deterioration of various coating properties. Similarly, a comparison of Example 1 and Comparative Example 2 and their performance test data shows that if only a single-functionalized POSS is used, the inability to form crosslinking centers also leads to deterioration in some of its properties.

[0111] Combining Examples 1 and 3-7 with the data in Table 1, it can be seen that when non-monofunctional functionalized POSS such as octaacryloyloxypropyl POSS, octavinyl POSS, octaglycidyloxypropyl POSS, or tetraglycidyloxypropyl-tetraisooctyl POSS are used in conjunction with acrylic acid as the functional monomers of the modified styrene-acrylic emulsion, the wall coatings made from the modified styrene-acrylic emulsion all have excellent washability and low VOC content. Moreover, the resulting coating surface has high hardness and good water resistance, and all can achieve surface drying within 2 hours. Thus, the wall coating can achieve excellent washability, high environmental protection, and good film-forming properties. Furthermore, under the condition of equal mass addition, the modified styrene-acrylic emulsion prepared by using tetraglycidyl oxypropyl-tetraisooctyl POSS as a functional monomer resulted in a coating with a lower surface hardness. This may be because the functionality of the functionalized POSS determines the degree of grafting and cross-linking between the POSS molecule and other monomers. As the functionality decreases, the cross-linking density of the cured coating also decreases, thereby reducing its surface hardness. Furthermore, when the functionalized POSS of tetrafunctionality accounts for 2-4% of the total mass of the modified styrene-acrylic emulsion, as the mass proportion of functionalized POSS increases, the VOC content of the subsequent wall coating only decreases slightly, while the rest remains largely unchanged. However, when the mass proportion of functionalized POSS reaches 6%, the washability of the wall coating decreases and falls below the test requirement of 6000 cycles. This may be because as the content of functionalized POSS increases, the proportion of acrylic acid decreases, which in turn affects the film-forming properties of the modified styrene-acrylic emulsion. Moreover, it may lead to an excess of functionalized POSS, as the excess functionalized POSS molecules are difficult to participate in the cross-linking reaction and instead form excess defect sites inside the coating, resulting in poor coating adhesion and making it easy to expose the substrate under high-intensity washing.

[0112] Based on Examples 6 and 8-11 and the data in Table 1, it can be seen that compared to using only dodecyl ester as a film-forming aid, using hexadecyl ester can reduce the VOC content of the wall coating to a certain extent, but it will significantly prolong the surface drying time of the coating. Conversely, using propylene glycol methyl ether propionate can significantly shorten the surface drying time of the coating, but at the same time, it will significantly increase the VOC content of the wall coating and reduce its surface hardness. When hexadecyl ester and propylene glycol methyl ether propionate are mixed and compounded at a mass ratio of (2.25-5.5):1, the synergistic effect of the two can maintain the VOC content of the wall coating at a low level, and can also give it high surface hardness and a moderate surface drying time, resulting in good overall performance.

[0113] Based on Examples 10 and 12-13 and the data in Table 1, it can be seen that when one of kaolin, talc, and wollastonite is used in combination with calcium carbonate and titanium dioxide as pigments and fillers, wall coatings with satisfactory washability, surface hardness, and film-forming properties can be obtained. In particular, when wollastonite is used in combination with calcium carbonate and titanium dioxide, the surface drying time of the wall coating can be shortened to a certain extent, with little impact on other test properties.

[0114] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A scrub resistant wall covering, characterized by: The total mass of the wall paint includes the following percentages of raw materials: Modified styrene-acrylic emulsion 20-28%, functional additives 5-8%, pigments and fillers 35-40%, protective additives 0.5-0.8%, balance is water; The raw materials for preparing the modified styrene-acrylic emulsion include functionalized POSS, wherein the functional groups of the functionalized POSS are one or more of alkenyl, epoxy and acryloyloxy groups, and the functionality is 4-8. The functional additives include at least a dispersant and a film-forming aid, wherein the dispersant is a fatty acid polyoxyethylene ester dispersant, and the film-forming aid includes one or a combination of two of alcohol ester film-forming aids and ether ester film-forming aids.

2. A scrub resistant wall covering according to claim 1, wherein: The modified styrene-acrylic emulsion comprises the following raw materials by mass percentage: Soft monomers 28-35%, hard monomers 16-20%, functional monomers 5-8%, emulsifiers 5-8%, initiators 1.5-3%, balance is water; The functional monomer is a composition of functionalized POSS and acrylic acid, and the mass ratio of the functionalized POSS to the acrylic acid is 1:(1-4).

3. A scrub resistant wall covering according to claim 2, wherein: The soft monomer is a composition of butyl acrylate, isooctyl acrylate and isodecanyl acrylate, and the mass ratio of butyl acrylate, isooctyl acrylate and isodecanyl acrylate is 1:(0.7-1):(0.1-0.3). The hard monomer is a composition of styrene and methyl methacrylate, and the mass ratio of styrene to methyl methacrylate is 1:(1.5-3).

4. A scrub resistant wall covering according to claim 3, wherein: The functionalized POSS is tetraglycidyl etheroxypropyl-tetraisooctyl POSS, and the functionalized POSS accounts for 2-4% of the total mass of the raw materials of the modified styrene-acrylic emulsion.

5. A washable wall coating according to claim 2, characterized in that: The preparation method of the modified styrene-acrylic emulsion includes the following steps: A1. By weight, mix 15-25% emulsifier and 45-55% water to obtain the base liquid; mix soft monomer, hard monomer, 55-65% emulsifier and 15-25% water to obtain the pre-emulsified monomer liquid; mix functional monomer, the remaining emulsifier and 15-25% water to obtain the pre-emulsified functional liquid; mix initiator and the remaining water to obtain the initiator liquid. A2. By weight, heat the base liquid to 80-83℃, add 10-15% initiator, stir evenly, and then slowly add the pre-emulsified monomer liquid, functional monomer liquid and 80-85% initiator liquid. Continue stirring the reaction and keep the temperature within 80-85℃. The addition should be completed within 3 hours, and the pre-emulsified monomer liquid, pre-emulsified functional liquid and 80-85% initiator liquid should be added simultaneously according to the mass ratio. A3. After the addition is complete, continue stirring for 10-15 minutes, add the remaining initiator solution, and heat to 88-90℃. Keep warm and continue stirring for 60-90 minutes. Adjust and control the pH value at 7-8 during the reaction to obtain the emulsion matrix. After taking a sample from the emulsion matrix and smelling it until there is no obvious irritating odor, cool it down to below 40℃ and filter it to obtain the modified styrene-acrylic emulsion.

6. A washable wall coating according to any one of claims 1-5, characterized in that: The functional additives also include defoamers, wetting agents, thickeners, solubilizers, and leveling agents, wherein the defoamers include front-end defoamers and back-end defoamers.

7. A washable wall coating according to claim 6, characterized in that: The film-forming aid is a composition of hexadecyl alcohol ester and propylene glycol methyl ether propionate, and the mass ratio of the hexadecyl alcohol ester to the propylene glycol methyl ether propionate is (2.25-5.5):

1.

8. A washable wall coating according to claim 6, characterized in that: The pigments and fillers include at least calcium carbonate and titanium dioxide, and also include one or more of wollastonite, talc and kaolin.

9. A washable wall coating according to claim 6, characterized in that: The protective additives include preservatives and mildew inhibitors, and the mass ratio of the preservatives to the mildew inhibitors is (1-1.5):

1.

10. A method for preparing a washable wall coating, used to prepare the washable wall coating as described in any one of claims 6-9, characterized in that, Includes the following steps: S1. Based on the mass fraction of each raw material, add 70-75% water to the dispersion tank and start stirring at a stirring speed of 400-600 r / min. While stirring, add the dispersant, the pre-stage defoamer and the wetting agent in sequence, and stir evenly. Then add the film-forming aid and the cosolvent in sequence, and stir evenly. Then slowly add the thickener and continue stirring until the system is obviously thickened and forms a semi-gel slurry to obtain the first slurry. S2. Maintain the stirring speed, add pigments and fillers to the first slurry, scrape the sides of the dispersion tank clean after the addition is complete, and rinse the sides of the tank and the stirring shaft with water. Increase the stirring speed to 1200-1500 r / min, maintain high-speed dispersion for 25-30 min, and take a sample to test the fineness of the slurry. When the fineness of the sampled slurry is ≤50μm, the second slurry is obtained. S3. Reduce the stirring speed to 600-800 r / min, and add 15-20% water, modified styrene-acrylic emulsion, downstream defoamer, protective agent and leveling agent to the second slurry in sequence. After the addition is completed, maintain the stirring speed to disperse for 5-10 minutes. Use the remaining water to rinse the tank side and stirring shaft to ensure that all raw materials are fully mixed into the system and stirred evenly to obtain the third slurry. S4. Based on the total mass of the third slurry in the tank, release 5-10% of the third slurry through the discharge valve, then pour it back into the dispersion tank, rinse with the remaining water, continue dispersion, filter and discharge to obtain the washable wall coating.

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