Preparation method of efficient waterproof odorless latex applied to indoor wall surface of building

Abstract

The invention discloses a preparation method of efficient waterproof odorless latex applied to an indoor wall surface of a building, and relates to the technical field of building materials, the method comprises the following components: S1, an emulsion preparation stage, S2, a kettle bottom material preparation stage, S3, a polymerization reaction stage, S4, a product refining stage, and S5, a product post-treatment stage. The building indoor wall latex with efficient waterproof performance is successfully prepared through fine formula design and strict production process control, and the selected raw materials including the acrylamide solution, the n-butyl acrylate and the styrene are fully emulsified and dispersed in the emulsion preparation stage, so that the emulsion is fully emulsified and dispersed; according to the present invention, the latex is combined with the nano-scale silica or nano calcium carbonate particle filler so as to form the compact and water-resistant coating structure, and in addition, the reaction condition and the dripping speed are accurately controlled in the polymerization reaction stage so as to ensure the full crosslinking and curing of the polymer chain in the latex, such that the waterproof performance is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, in particular to a method for preparing a high-efficiency waterproof and odor-free latex applied to indoor walls of buildings. Background Art

[0002] With the continuous development of the modern construction industry, the requirements for interior wall materials are increasing day by day, especially the demand for their waterproof performance and environmental protection characteristics is becoming more and more urgent. As a new type of interior wall decoration material, high-efficiency waterproof and odor-free latex has attracted much attention due to its excellent waterproof performance and environmental protection and odor-free characteristics.

[0003] The traditional preparation method of building interior wall latex has obvious deficiencies in waterproof performance and environmental protection characteristics. On the one hand, the waterproof performance of traditional latex is often not ideal, and it is difficult to keep the wall dry and clean for a long time, which can easily lead to leakage and mildew problems, which not only affects the living experience, but may also cause damage to the building structure. On the other hand, traditional latex may use raw materials and additives containing volatile organic compounds in the preparation process. These substances will release harmful gases during construction and use, causing potential harm to human health and the environment. In addition, the preparation process of traditional latex is relatively simple, lacking sophisticated formula design and strict production control, resulting in unstable product quality, which is difficult to meet the needs of modern buildings for high-quality, high-performance wall materials.

[0004] In summary, traditional building interior wall latex has obvious defects in waterproof performance and environmental protection characteristics, which makes it difficult to meet the demand of the modern construction industry for high-quality, high-performance wall materials. Therefore, it is particularly important to develop a preparation method for high-efficiency waterproof and odor-free latex for use in building interior walls. Summary of the Invention

[0005] The purpose of the present invention is to make up for the shortcomings of the existing technology and provide a preparation method of high-efficiency waterproof and odor-free latex for use on indoor walls of buildings. It can prepare indoor wall latex of buildings that has both high-efficiency waterproof performance and meets environmental protection and odor-free requirements through careful formula design and strict production process control. The implementation of this preparation method will help improve the waterproof performance of indoor walls of buildings, extend the service life of buildings, reduce the maintenance costs and troubles caused by leakage, and meet the higher requirements of modern buildings for green and environmental protection.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for preparing a high-efficiency waterproof and odor-free latex for use on indoor walls of buildings, the specific steps of the method are: S1, emulsion preparation stage Select an anionic emulsifier to prepare emulsifier 1 solution and ensure that it is completely dissolved in water to form a homogeneous system. Add water to the emulsifier kettle, start stirring, adjust the speed to 50HZ, add the dissolved emulsifier 1, and stir for 15 minutes; Add acrylamide solution, n-butyl acrylate and styrene, select nano-silica, and then add the above mixed system; Continue emulsification for 45 minutes, then adjust the stirring speed to 20 Hz. When there is 1 hour left in the dropwise addition, increase the stirring speed of the emulsifier to 40 Hz and add the crosslinking agent. S2, kettle bottom material preparation stage First, add water to the polymerization reactor, start stirring, set the speed to 18HZ, and pass steam through the jacket to increase the temperature; When the temperature reaches 80°C, add dissolved sodium carbonate, emulsifier 2, sodium dodecyl diphenyl ether disulfonate, and sodium chloride or potassium chloride as electrolyte particles to control the early reaction speed and prevent the reaction from being too fast and producing slag; S3, polymerization reaction stage Heat the reaction system to 84°C, add the dissolved ammonium persulfate initiator, and stir for one minute; Simultaneously, start adding the emulsion of component A and the initiator ammonium persulfate of component D dropwise. The drop rate of the emulsion of component A is controlled at 30-50 drops per minute, and the drop rate of the initiator ammonium persulfate of component D is controlled at 25-40 drops per minute. The dropwise addition time of component A is 3 hours. The reaction temperature is controlled at 90-92°C for the first half hour and at 88-90°C for the next two hours. The dropwise addition time of component D is 3 hours and 10 minutes. After the addition of components A and D is completed, rinse the reactor with water and then keep it warm for 1 hour at 91-93°C. During the warming period, the temperature can be appropriately increased to promote the reaction. S4, product refining stage After the insulation was completed, the reaction system was cooled to 70°C and TBHP aqueous solution was prepared as component E and component G; Slowly add component E dropwise and stir for 5 minutes to prepare sodium bisulfite or ascorbic acid aqueous solution as component F and component H; Add component F dropwise over 20 minutes, keep warm for 15 minutes, slowly add component G, and stir for 5 minutes; Add component H dropwise within 20 minutes and keep warm for 15 minutes. The entire addition process must be carried out in the dark. The temperature in the kettle was controlled at 70°C, the kettle was vacuumed, and degassing was performed for 4 hours to remove the remaining monomers in the emulsion by thermal degassing; S5, product post-processing stage The reaction system was cooled to 40°C, and an ammonia solution was prepared as component I. Component I was slowly added dropwise while the pH value of the emulsion was monitored in real time using a pH meter. The mixture was stirred for 5 minutes. Add silicone defoamer as component J and add emulsion; Add preservative component K and component L in a specific ratio and stir for 5 minutes to effectively extend the shelf life of the emulsion; The material was discharged and filtered through 120 mesh for testing; The volatile oil is extracted from lemon by steam distillation as a natural plant fragrance. After passing the test, it is added into the emulsion and the stirring speed is controlled at 20-30HZ to make the fragrance evenly dispersed in the latex.

[0007] Furthermore, in the emulsion preparation stage, the dissolved emulsifier 1 is an anionic emulsifier with a concentration of 3-5 g / L. Before adding acrylamide solution, n-butyl acrylate and styrene, it is necessary to ensure that the emulsifier 1 is completely dissolved in water and forms a uniform emulsified system.

[0008] Furthermore, the nano-scale silica or nano-calcium carbonate particles added during the emulsion preparation stage have a particle size range of 20-50 nm, and the added amount is 0.5%-1.5% of the total mass of n-butyl acrylate and styrene. Ultrasonic dispersion equipment is used to disperse them for 15-30 minutes before addition to ensure that the nanoparticles are evenly distributed in the latex system.

[0009] Furthermore, the electrolyte particles added in the kettle bottom material preparation stage are sodium chloride or potassium chloride, and the addition amount is 0.1-0.3g per liter of water. By precisely controlling the addition amount of electrolyte particles, the reaction speed in the early stage of the reaction is accurately regulated to ensure stable reaction.

[0010] Furthermore, during the polymerization reaction stage, the droplet addition rate of the emulsion of component A is controlled at 30-50 drops per minute, and the droplet addition rate of the initiator ammonium persulfate of component D is controlled at 25-40 drops per minute. During the droplet addition process, the viscosity of the reaction system is monitored every 15-20 minutes. If the viscosity change exceeds ±10% of the set range, the stirring speed is adjusted accordingly.

[0011] Furthermore, in the product refining stage, components E and G used to remove residual monomers are aqueous solutions with a concentration of 5-10%, and the reducing agent in components F and H is sodium bisulfite or ascorbic acid, and its concentration is 3-7% aqueous solution. The dropwise addition process needs to be carried out under light-proof conditions to prevent the reducing agent from being oxidized.

[0012] Furthermore, in the post-processing stage of the product, component I for adjusting the pH value is an ammonia solution with a concentration of 10-15%, which needs to be added slowly dropwise, and a pH meter is used to monitor the pH value of the emulsion in real time to ensure that the final pH value is stable between 7.2-7.8.

[0013] Furthermore, the defoaming agent J added in the product post-processing stage is a silicone defoaming agent, and the added amount is 0.05%-0.15% of the total mass of the emulsion. The speed during stirring is controlled at 15-25HZ, and the stirring time is strictly controlled at 10-12 minutes to ensure effective elimination of foam in the emulsion system.

[0014] Furthermore, the natural plant flavor is volatile oil extracted from lemon, the extraction method adopts steam distillation, the extraction rate is not less than 0.5%, and it is added after the product is tested and qualified in the post-processing stage. The added amount is 0.01%-0.03% of the total mass of the emulsion. After addition, the stirring speed is controlled at 20-30HZ, and the stirring time is 15-20 minutes.

[0015] Compared with the prior art, the preparation method of the high-efficiency waterproof and odor-free latex applied to interior walls of buildings has the following beneficial effects: 1. This preparation method successfully prepares a building interior wall latex with high-efficiency waterproof performance through careful formula design and strict production process control. Among them, the selected acrylamide solution, n-butyl acrylate and styrene raw materials are fully emulsified and dispersed in the emulsion preparation stage, and work together with nano-scale silica or nano-calcium carbonate particle fillers to form a dense and water-resistant coating structure. In addition, in the polymerization reaction stage, by precisely controlling the reaction conditions and dripping speed, it is ensured that the polymer chains in the latex are fully cross-linked and cured, thereby further improving its waterproof performance. The use of this high-efficiency waterproof and odor-free latex can significantly improve the waterproof performance of building interior walls, extend the service life of the building, and at the same time reduce the maintenance costs and troubles caused by leakage.

[0016] 2. This preparation method reduces potential harm to the environment and human body by selecting low-volatility, low-toxicity raw materials and additives in the emulsion preparation and polymerization reaction stages. Secondly, in the product refining stage, the thermal degassing method is used to remove residual monomers in the emulsion, which effectively reduces the odor and irritation of the product. In addition, this preparation method also uses volatile oil extracted from lemon as a natural plant fragrance, which not only increases the natural aroma of the product, but also further enhances its environmental performance. This odorless and environmentally friendly characteristic makes the high-efficiency waterproof and odorless latex safer and healthier when used on interior walls of buildings, meeting the higher requirements of modern buildings for green and environmental protection.

[0017] Other advantages, objects and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be learned from the practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0019] Figure 1 The present invention is a process flow chart of a method for preparing a high-efficiency waterproof and odor-free latex used for interior walls of buildings. DETAILED DESCRIPTION

[0020] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments. Comparative Example

[0021] An anionic emulsifier was used to prepare the emulsifier 1 solution with a concentration of 4 g / L, and it was ensured to be completely dissolved in water to form a homogeneous system.

[0022] Add appropriate amount of water into the emulsification kettle, start stirring, adjust the speed to 50HZ, add the dissolved emulsifier 1, and stir for 15 minutes.

[0023] Add acrylamide solution, n-butyl acrylate and styrene, select nano-silica with a particle size range of 30nm, and add it in an amount of 1% of the total mass of n-butyl acrylate and styrene. Use ultrasonic dispersion equipment to disperse it for 20 minutes before adding it, and then add it to the above mixed system.

[0024] Emulsification was continued for 45 minutes, after which the stirring speed was adjusted to 20 Hz. When there was 1 hour remaining in the dropwise addition, the stirring speed of the emulsification kettle was increased to 40 Hz, and the cross-linking agent was added.

[0025] First, add an appropriate amount of water into the polymerization reactor, start stirring, set the speed to 18HZ, and pass steam through the jacket to increase the temperature.

[0026] When the temperature reaches 80°C, add dissolved sodium carbonate, emulsifier 2, and sodium dodecyl diphenyl ether disulfonate, and add sodium chloride as electrolyte particles in an amount of 0.2g per liter of water to regulate the early reaction speed and prevent the reaction from being too fast and producing slag.

[0027] The reaction system was heated to 84°C, and the dissolved ammonium persulfate initiator was added and stirred for one minute.

[0028] At the same time, start adding the emulsion of component A and the initiator ammonium persulfate of component D dropwise. The drop rate of the emulsion of component A is controlled at 40 drops per minute, and the drop rate of the initiator ammonium persulfate of component D is controlled at 30 drops per minute. During the dropwise addition process, monitor the viscosity of the reaction system every 15 minutes. If the viscosity change exceeds ±10% of the set range, adjust the stirring speed accordingly.

[0029] The dropwise addition time of component A was 3 hours, the reaction temperature was controlled at 91°C in the first half hour and then at 89°C for the next two hours, and the dropwise addition time of component D was 3 hours and 10 minutes.

[0030] After the addition of components A and D was completed, the reactor was rinsed with water and then kept warm for 1 hour at 92°C. The temperature was appropriately increased during the warming period to promote the reaction to proceed fully.

[0031] After the insulation was completed, the reaction system was cooled to 70° C., and an 8% TBHP aqueous solution was prepared as component E and component G.

[0032] Component E was slowly added dropwise and stirred for 5 minutes. A 5% aqueous sodium bisulfite solution was prepared as components F and H.

[0033] Add component F dropwise over 20 minutes, keep warm for 15 minutes, slowly add component G, and stir for 5 minutes.

[0034] Add component H dropwise within 20 minutes and keep warm for 15 minutes. The entire addition process must be carried out in the dark.

[0035] The temperature in the kettle was controlled at 70° C., the kettle was vacuumed, and degassing was performed for 4 hours. The remaining monomers in the emulsion were removed by thermal degassing.

[0036] The reaction system was cooled to 40°C, and a 12% ammonia aqueous solution was prepared as component I. Component I was slowly added dropwise while the pH value of the emulsion was monitored in real time using a pH meter. The mixture was stirred for 5 minutes to ensure that the final pH value was stable at 7.5.

[0037] An organosilicon defoamer was added as component J in an amount of 0.1% of the total mass of the emulsion. The stirring speed was controlled at 20 Hz and the stirring time was 10 minutes.

[0038] Add preservative component K and component L in a specific ratio and stir for 5 minutes to effectively extend the shelf life of the emulsion.

[0039] The material was discharged and filtered through 120 mesh for testing.

[0040] The steam distillation method was used to extract volatile oil from lemon as a natural plant flavor, with an extraction rate of 0.6%. After passing the test, the volatile oil was added to the emulsion in an amount of 0.02% of the total mass of the emulsion. The stirring speed was controlled at 25HZ and the stirring time was 15 minutes to ensure that the flavor was evenly dispersed in the latex. Example 1

[0041] According to the above comparative examples 1, 2 and 3, only the content of nano-silicon dioxide was changed, and an anionic emulsifier was selected to prepare the emulsifier 1 solution to a concentration of 4 g / L, and it was ensured to be completely dissolved in water to form a uniform system.

[0042] Add appropriate amount of water into the emulsification kettle, start stirring, adjust the speed to 50HZ, add the dissolved emulsifier 1, and stir for 15 minutes.

[0043] Add acrylamide solution, n-butyl acrylate and styrene, select nano-scale silica with a particle size range of 30nm, and add 0.75% of the total mass of n-butyl acrylate and styrene. Use ultrasonic dispersion equipment to disperse for 20 minutes before adding, and then add the above mixed system.

[0044] Emulsification was continued for 45 minutes, after which the stirring speed was adjusted to 20 Hz. When there was 1 hour remaining in the dropwise addition, the stirring speed of the emulsification kettle was increased to 40 Hz, and the cross-linking agent was added.

[0045] Effect: The water-impermeability is 0.25MPa, and it is water-impermeable for 30 minutes. The nano-silica content is lower than that of the original embodiment, the pore filling effect is slightly inferior, and the waterproof pressure is slightly lower, but it can also meet the basic waterproofing requirements of indoor walls.

[0046] After 6 months of accelerated aging test simulation when stored at room temperature of 25°C and relative humidity of 60%, the change rate of the latex's tensile strength and elongation at break performance indicators was within ±10%. The reduction in nano-silica content had a certain impact on the structural stability, resulting in slightly larger fluctuations in performance indicators after aging. Example 2

[0047] An anionic emulsifier was used to prepare the emulsifier 1 solution with a concentration of 4 g / L, and it was ensured to be completely dissolved in water to form a homogeneous system.

[0048] Add appropriate amount of water into the emulsification kettle, start stirring, adjust the speed to 50HZ, add the dissolved emulsifier 1, and stir for 15 minutes.

[0049] Add acrylamide solution, n-butyl acrylate and styrene, select nano-silica with a particle size range of 30nm, and add 1.25% of the total mass of n-butyl acrylate and styrene. Use ultrasonic dispersion equipment to disperse for 20 minutes before adding, and then add the above mixed system.

[0050] Emulsification was continued for 45 minutes, after which the stirring speed was adjusted to 20 Hz. When there was 1 hour remaining in the dropwise addition, the stirring speed of the emulsification kettle was increased to 40 Hz, and the cross-linking agent was added.

[0051] Effect: Waterproofness can reach 0.35MPa, and it is watertight for 30 minutes. The higher content of nano-silica further fills the pores, enhances the density of latex, and improves waterproof performance.

[0052] After 6 months of accelerated aging test simulation when stored at room temperature of 25°C and relative humidity of 60%, the change rate of the latex's tensile strength and elongation at break performance indicators was within ±9%. The larger amount of nano-silica helps to stabilize the latex structure, and the performance indicators change less after aging. Example 3

[0053] An anionic emulsifier was used to prepare the emulsifier 1 solution with a concentration of 4 g / L, and it was ensured to be completely dissolved in water to form a homogeneous system.

[0054] Add appropriate amount of water into the emulsification kettle, start stirring, adjust the speed to 50HZ, add the dissolved emulsifier 1, and stir for 15 minutes.

[0055] Add acrylamide solution, n-butyl acrylate and styrene, select nano-silica with a particle size range of 30nm, and add 1.75% of the total mass of n-butyl acrylate and styrene. Use ultrasonic dispersion equipment to disperse for 20 minutes before adding, and then add the above mixed system.

[0056] Emulsification was continued for 45 minutes, after which the stirring speed was adjusted to 20 Hz. When there was 1 hour remaining in the dropwise addition, the stirring speed of the emulsification kettle was increased to 40 Hz, and the cross-linking agent was added.

[0057] Effect: The water-impermeability can reach 0.42MPa, and it is water-impermeable for 30 minutes. The increase in nano-silica content greatly improves the waterproof performance of latex and can more effectively block water penetration.

[0058] After 6 months of accelerated aging test simulation when stored at room temperature of 25°C and relative humidity of 60%, the change rate of the latex's tensile strength and elongation at break performance indicators was within ±7.5%. The high content of nano-silica makes the latex structure more stable and the performance fluctuations are smaller during aging. However, due to the increase in nanoparticles, the viscosity of the system may increase, which may have a certain impact on the smoothness of construction and application (further testing of construction performance-related indicators is required). Example 4

[0059] An anionic emulsifier was used to prepare the emulsifier 1 solution with a concentration of 4 g / L, and it was ensured to be completely dissolved in water to form a homogeneous system.

[0060] Add appropriate amount of water into the emulsification kettle, start stirring, adjust the speed to 50HZ, add the dissolved emulsifier 1, and stir for 15 minutes.

[0061] Add acrylamide solution, n-butyl acrylate and styrene, select nano-silica with a particle size range of 30nm, and add it in an amount of 1% of the total mass of n-butyl acrylate and styrene. Use ultrasonic dispersion equipment to disperse it for 20 minutes before adding it, and then add it to the above mixed system.

[0062] Emulsification was continued for 45 minutes, after which the stirring speed was adjusted to 20 Hz. When there was 1 hour remaining in the dropwise addition, the stirring speed of the emulsification kettle was increased to 40 Hz, and the cross-linking agent was added.

[0063] The reaction system was cooled to 40°C, a 12% ammonia solution was prepared as component I, component I was slowly added dropwise, and the pH value of the emulsion was monitored in real time using a pH meter, and stirred for 5 minutes to ensure that the final pH value was stable between 7.5, and a silicone defoamer was added as component J in an amount of 0.1% of the total mass of the emulsion. The stirring speed was controlled at 20HZ for 10 minutes, and the preservative components K and L were added in a specific proportion respectively, and stirred for 5 minutes. The material was discharged and filtered through 120 mesh for testing. Volatile oil was extracted from lemon by steam distillation as a natural plant flavor, and the extraction rate was 0.6%. After passing the test, the emulsion was added in an amount of 0.01% of the total mass of the emulsion, the stirring speed was controlled at 25HZ, and the stirring time was 15 minutes to make the flavor evenly dispersed in the latex.

[0064] Effect: The odor intensity dropped to level 3. At this time, the faint odor of latex itself can still be clearly smelled. The effect of lemon essential oil on improving the odor is limited and can only cover up part of the odor to a certain extent. Example 5

[0065] An anionic emulsifier was used to prepare the emulsifier 1 solution with a concentration of 4 g / L, and it was ensured to be completely dissolved in water to form a homogeneous system.

[0066] Add appropriate amount of water into the emulsification kettle, start stirring, adjust the speed to 50HZ, add the dissolved emulsifier 1, and stir for 15 minutes.

[0067] Add acrylamide solution, n-butyl acrylate and styrene, select nano-silica with a particle size range of 30nm, and add it in an amount of 1% of the total mass of n-butyl acrylate and styrene. Use ultrasonic dispersion equipment to disperse it for 20 minutes before adding it, and then add it to the above mixed system.

[0068] Emulsification was continued for 45 minutes, after which the stirring speed was adjusted to 20 Hz. When there was 1 hour remaining in the dropwise addition, the stirring speed of the emulsification kettle was increased to 40 Hz, and the cross-linking agent was added.

[0069] The reaction system was cooled to 40°C, a 12% ammonia solution was prepared as component I, component I was slowly added dropwise, and the pH value of the emulsion was monitored in real time using a pH meter, and stirred for 5 minutes to ensure that the final pH value was stable between 7.5, and a silicone defoamer was added as component J in an amount of 0.1% of the total mass of the emulsion. The stirring speed was controlled at 20HZ and the stirring time was 10 minutes. The preservative components K and L were added in a specific proportion and stirred for 5 minutes. The material was discharged and filtered through 120 mesh for testing. Volatile oil was extracted from lemon by steam distillation as a natural plant flavor, and the extraction rate was 0.6%. After passing the test, the emulsion was added in an amount of 0.03% of the total mass of the emulsion. The stirring speed was controlled at 25HZ and the stirring time was 15 minutes to make the flavor evenly dispersed in the latex.

[0070] Effect: The odor intensity is reduced to level 1, and the latex has almost no odor. Instead, it is replaced by a fresh lemon scent, which can create a very comfortable odor environment indoors. Example 6

[0071] An anionic emulsifier was used to prepare the emulsifier 1 solution with a concentration of 4 g / L, and it was ensured to be completely dissolved in water to form a homogeneous system.

[0072] Add appropriate amount of water into the emulsification kettle, start stirring, adjust the speed to 50HZ, add the dissolved emulsifier 1, and stir for 15 minutes.

[0073] Add acrylamide solution, n-butyl acrylate and styrene, select nano-silica with a particle size range of 30nm, and add it in an amount of 1% of the total mass of n-butyl acrylate and styrene. Use ultrasonic dispersion equipment to disperse it for 20 minutes before adding it, and then add it to the above mixed system.

[0074] Emulsification was continued for 45 minutes, after which the stirring speed was adjusted to 20 Hz. When there was 1 hour remaining in the dropwise addition, the stirring speed of the emulsification kettle was increased to 40 Hz, and the cross-linking agent was added.

[0075] The reaction system was cooled to 40°C, a 12% ammonia solution was prepared as component I, component I was slowly added dropwise, and the pH value of the emulsion was monitored in real time using a pH meter, and stirred for 5 minutes to ensure that the final pH value was stable between 7.5, and a silicone defoamer was added as component J in an amount of 0.1% of the total mass of the emulsion. The stirring speed was controlled at 20HZ and the stirring time was 10 minutes. The preservative components K and L were added in a specific proportion and stirred for 5 minutes. The material was discharged and filtered through 120 mesh for testing. Volatile oil was extracted from lemon by steam distillation as a natural plant flavor, and the extraction rate was 0.6%. After passing the test, the emulsion was added in an amount of 0.05% of the total mass of the emulsion. The stirring speed was controlled at 25HZ and the stirring time was 15 minutes to make the flavor evenly dispersed in the latex.

[0076] Effect: The odor intensity is level 1, but the lemon scent is too strong. Some people may find it pungent and may feel uncomfortable if they stay in this environment for a long time.

[0077] The specific contents are shown in the following table:

[0078] As shown in the table above, Examples 1 to 3 only change the proportion of nano-silica in the total mass of n-butyl acrylate and styrene, and other parameters remain unchanged, which will cause obvious differences in the performance of the latex. When the nano-silica content is 0.75%, it has a certain waterproof ability, but the performance index fluctuates relatively greatly after aging. When the content is increased to 1.25%, the waterproof performance is improved to 0.35MPa of impermeability, and it is impermeable for 30 minutes. The change of aging performance index is reduced. When the content reaches 1.75%, the waterproof performance is further improved to 0.42MPa, and it is impermeable for 30 minutes. The change of aging performance index is even smaller, but it may have a potential impact on the construction performance. It can be seen that an appropriate increase in the nano-silica content can effectively improve the waterproof performance and stability of the latex. In actual applications, it is necessary to comprehensively consider its impact on other properties in order to determine the optimal formula. Examples 4 to 6 only change the amount of lemon volatile oil added, which will have a significant impact on the odor of the latex. When the addition amount is 0.01% of the total mass of the emulsion, the odor improvement effect is poor, and the latex odor can still be smelled. When the addition amount is increased to 0.03%, the odor intensity is reduced to level 1, which can effectively remove the odor and bring a fresh lemon aroma, creating a comfortable environment. When the addition amount reaches 0.05%, although the odor intensity is still level 1, the lemon aroma is too strong and may cause discomfort to some people. Therefore, in actual production, it is necessary to comprehensively consider the public's acceptance of the odor and select the appropriate amount of lemon volatile oil added to achieve the best odor improvement effect while ensuring other properties of the latex.

[0079] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a high-efficiency waterproof and odor-free latex for use on indoor building walls, characterized in that: The specific steps of the preparation method are: S1, emulsion preparation stage Select an anionic emulsifier to prepare emulsifier 1 solution and ensure that it is completely dissolved in water to form a homogeneous system. Add water to the emulsifier kettle, start stirring, adjust the speed to 50HZ, add the dissolved emulsifier 1, and stir for 15 minutes; Add acrylamide solution, n-butyl acrylate and styrene, select nano-silica, and then add the above mixed system; Continue emulsification for 45 minutes, then adjust the stirring speed to 20 Hz. When there is 1 hour left in the dropwise addition, increase the stirring speed of the emulsifier to 40 Hz and add the crosslinking agent. S2, kettle bottom material preparation stage First, add water to the polymerization reactor, start stirring, set the speed to 18HZ, and pass steam through the jacket to increase the temperature; When the temperature reaches 80°C, add dissolved sodium carbonate, emulsifier 2, sodium dodecyl diphenyl ether disulfonate, and sodium chloride or potassium chloride as electrolyte particles to control the early reaction speed and prevent the reaction from being too fast and producing slag; S3, polymerization reaction stage Heat the reaction system to 84°C, add the dissolved ammonium persulfate initiator, and stir for one minute; Simultaneously, start adding the emulsion of component A and the initiator ammonium persulfate of component D dropwise. The drop rate of the emulsion of component A is controlled at 30-50 drops per minute, and the drop rate of the initiator ammonium persulfate of component D is controlled at 25-40 drops per minute. The dropwise addition time of component A is 3 hours. The reaction temperature is controlled at 90-92°C for the first half hour and at 88-90°C for the next two hours. The dropwise addition time of component D is 3 hours and 10 minutes. After the addition of components A and D is completed, rinse the reactor with water and then keep it warm for 1 hour at 91-93°C. During the warming period, the temperature can be appropriately increased to promote the reaction. S4, product refining stage After the insulation was completed, the reaction system was cooled to 70°C and TBHP aqueous solution was prepared as component E and component G; Slowly add component E dropwise and stir for 5 minutes to prepare sodium bisulfite or ascorbic acid aqueous solution as component F and component H; Add component F dropwise over 20 minutes, keep warm for 15 minutes, slowly add component G, and stir for 5 minutes; Add component H dropwise within 20 minutes and keep warm for 15 minutes. The entire addition process must be carried out in the dark. The temperature in the kettle was controlled at 70°C, the kettle was vacuumed, and degassing was performed for 4 hours to remove the remaining monomers in the emulsion by thermal degassing; S5, product post-processing stage The reaction system was cooled to 40°C, and an ammonia solution was prepared as component I. Component I was slowly added dropwise while the pH value of the emulsion was monitored in real time using a pH meter. The mixture was stirred for 5 minutes. Add silicone defoamer as component J and add emulsion; Add preservative component K and component L in a specific ratio and stir for 5 minutes to effectively extend the shelf life of the emulsion; The material was discharged and filtered through 120 mesh for testing; The volatile oil is extracted from lemon by steam distillation as a natural plant fragrance. After passing the test, it is added into the emulsion and the stirring speed is controlled at 20-30HZ to make the fragrance evenly dispersed in the latex.

2. The method for preparing a high-efficiency waterproof and odor-free latex for use on interior walls of buildings according to claim 1, wherein: During the emulsion preparation stage, the dissolved emulsifier 1 is an anionic emulsifier with a concentration of 3-5 g / L. Before adding acrylamide solution, n-butyl acrylate and styrene, it is necessary to ensure that the emulsifier 1 is completely dissolved in water and forms a uniform emulsified system.

3. The method for preparing a high-efficiency waterproof and odor-free latex for use on interior walls of buildings according to claim 1, wherein: The nano-scale silicon dioxide or nano-calcium carbonate particles added in the emulsion preparation stage have a particle size range of 20-50 nm and an addition amount of 0.5%-1.5% of the total mass of n-butyl acrylate and styrene. Ultrasonic dispersion equipment is used to disperse the particles for 15-30 minutes before addition.

4. The method for preparing a high-efficiency waterproof and odor-free latex for use on interior walls of buildings according to claim 1, wherein: The electrolyte particles added in the kettle bottom material preparation stage are sodium chloride or potassium chloride, and the addition amount is 0.1-0.3g per liter of water. The reaction speed in the early stage of the reaction is precisely controlled by precisely controlling the addition amount of the electrolyte particles.

5. The method for preparing a high-efficiency waterproof and odor-free latex for use on interior walls of buildings according to claim 1, wherein: During the polymerization reaction stage, the droplet addition rate of the emulsion of component A is controlled at 30-50 drops per minute, and the droplet addition rate of the initiator ammonium persulfate of component D is controlled at 25-40 drops per minute. During the droplet addition process, the viscosity of the reaction system is monitored every 15-20 minutes. If the viscosity change exceeds ±10% of the set range, the stirring speed is adjusted accordingly.

6. The method for preparing a high-efficiency waterproof and odor-free latex for use on interior walls of buildings according to claim 1, characterized in that: In the product refining stage, components E and G used to remove residual monomers are aqueous solutions with a concentration of 5-10%, and the reducing agent in components F and H is sodium bisulfite or ascorbic acid with a concentration of 3-7% aqueous solution. The dropwise addition process must be carried out in the dark to prevent the reducing agent from being oxidized.

7. The method for preparing a high-efficiency waterproof and odor-free latex for use on interior walls of buildings according to claim 1, characterized in that: Component I for adjusting the pH value in the post-processing stage of the product is an ammonia solution with a concentration of 10-15%, which needs to be added slowly dropwise. At the same time, a pH meter is used to monitor the pH value of the emulsion in real time to ensure that the final pH value is stable between 7.2-7.

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8. The method for preparing a high-efficiency waterproof and odor-free latex for use on interior walls of buildings according to claim 1, characterized in that: The defoamer J added in the post-processing stage of the product is a silicone defoamer, and the added amount is 0.05%-0.15% of the total mass of the emulsion. The speed during stirring is controlled at 15-25HZ, and the stirring time is strictly controlled at 10-12 minutes.

9. The method for preparing a high-efficiency waterproof and odor-free latex for use on interior walls of buildings according to claim 1, characterized in that: The natural plant fragrance is volatile oil extracted from lemon, and the extraction method adopts steam distillation, with an extraction rate of not less than 0.5%. It is added after the product is tested and qualified in the post-processing stage, and the added amount is 0.01%-0.03% of the total mass of the emulsion. After addition, the stirring speed is controlled at 20-30HZ, and the stirring time is 15-20 minutes.

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