Building interior wall purification coating system with dynamic migration regeneration function and preparation method thereof

Abstract

The invention discloses a building interior wall purification coating system with dynamic migration and regeneration functions and a preparation method of the building interior wall purification coating system. The system comprises a reinforcing putty layer, a permeation reinforcing primer layer and a purification functional finish paint layer which are sequentially arranged from inside to outside. The purification functional finish paint layer comprises a calcium-manganese-silicon composite functional material, an adsorption material with bimodal pore size distribution, cerium-doped titanium dioxide, an inorganic cementing material, an organic bonding film-forming substance and a plant polyphenol cross-linking agent. The calcium-manganese-silicon composite functional material has a composite phase structure of layered calcium silicate and manganese potassium ore type manganese dioxide, and the element composition of the calcium-manganese-silicon composite functional material meets a specific range. Through the arrangement of the three-layer structure and the cooperation of all components in the finish paint, the system forms a microenvironment for supporting directional migration of functional materials, so that pollutants such as formaldehyde can be subjected to continuous catalytic purification and humidity adjustment. Tests show that the 24-hour purification rate of formaldehyde is greater than 94%, and the 28-day purification durability is greater than 88%.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a building interior wall coating system with air purification and humidity regulation functions, and particularly to a coating system and its preparation method that achieves long-lasting purification performance through the dynamic migration of functional materials. Background Technology

[0002] Indoor air pollution, especially volatile organic compound (VOC) pollution such as formaldehyde, is an environmental problem that needs to be addressed. Common functional interior wall materials, such as paints with added activated carbon or diatomaceous earth, mainly purify the air through physical adsorption, but they suffer from limited adsorption capacity, easy saturation, and lack of degradation capabilities. Another type of material, such as paints with added photocatalysts or transition metal oxides, can degrade pollutants through catalytic oxidation, but it usually faces the following challenges: First, the active components often exist in the form of fixed fillers, and once their surface active sites are covered or deactivated by reaction intermediates, they cannot be replenished, leading to rapid functional decay; second, the active components have poor compatibility with the organic matrix of the paint, easily agglomerating or affecting the physical properties of the coating; third, traditional photocatalysts are inefficient under low-light indoor conditions.

[0003] Existing technologies mostly focus on the modification or simple compounding of single functional components, lacking a system-level design to achieve a dynamic balance between the consumption and replenishment of active components. This is a major reason for the insufficient durability of interior wall purification materials. Therefore, developing an interior wall coating system capable of long-lasting, self-renewing purification is an urgent problem to be solved. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the defect of poor functional durability of existing interior wall purification materials due to the fixed and easily deactivated active components.

[0005] To address the aforementioned technical problems, this invention provides a building interior wall purification coating system with dynamic migration and regeneration capabilities. The system comprises, from the inside out, a reinforcing putty layer, a penetrating reinforcing primer layer, and a purification functional topcoat layer, applied sequentially to the building substrate.

[0006] The reinforcing putty layer mainly serves to level and reinforce the substrate. The dense and alkaline base layer it forms provides a stable physical and chemical foundation for the entire system. By dry film weight percentage, its composition is: 30-60% water-resistant inorganic cementitious material, 20-50% aggregate, 0.1-2% reinforcing fiber, with the balance being water and additives.

[0007] The primary function of the penetrating and reinforcing primer layer is to deeply penetrate the pores within the putty layer and strengthen its surface. It reacts with the putty layer to form a highly adhesive, porous inorganic-organic hybrid gel network rich in silanol groups. This network provides a strong anchoring foundation for the topcoat layer and serves as a channel for moisture and ion transport. By dry film weight percentage, its composition is: 20-50% silane-modified silica sol, with the balance being water and small-molecule alcohol solvents.

[0008] The purification-functional topcoat layer is the core layer for achieving air purification and humidity regulation. By dry film weight percentage, it consists of the following components: 8-15% calcium-manganese-silicon composite functional material, 5-10% adsorbent material with a bimodal pore size distribution, 2-6% cerium-doped titanium dioxide, 15-30% inorganic cementing material, 10-25% organic binder film-forming substance, 0.5-3% plant polyphenol crosslinking agent, and the balance being water, dispersant, thickener, defoamer, and pH adjuster.

[0009] The key to this invention lies in the aforementioned calcium-manganese-silicon composite functional material. This material is obtained through hydrothermal synthesis and possesses a two-phase composite structure of layered calcium silicate and manganese potassium oxide. Its manganese content is 9.0-15.0% by weight, and the calcium-silicon molar ratio is 1.6:1-2.1:1. This unique composition and structure endow it with two important properties: excellent catalytic oxidation activity and good compatibility with the inorganic network of the coating, as well as moderate surface hydrophilicity.

[0010] In the three-dimensional elastic network formed by the curing of the topcoat layer, which is constructed from an organic binder film-forming substance containing a specific silicone-acrylic emulsion and a starch graft copolymer, and a tannic acid crosslinking agent, the material particles are not completely fixed. When changes in ambient humidity cause moisture transport within the coating, the hydrophilic calcium manganese silicon particles can use water molecules as a medium to slowly and directionally migrate from the coating's abundant interior to the region where surface active sites are consumed, driven by capillary action and concentration gradients. This "dynamic migration" characteristic is the core mechanism by which this system achieves functional regeneration.

[0011] In the adsorbent material with a bimodal pore size distribution, micropores are used to efficiently adsorb small molecule pollutants such as formaldehyde and enrich them near the catalytic site; mesopores mainly undertake the adsorption and desorption of water to achieve the humidity regulation function, and at the same time provide a transport channel for pollutant molecules and migrating functional material particles.

[0012] The cerium-doped titanium dioxide serves as an auxiliary catalyst. The doping of cerium extends its photoresponse range to the visible light region. Under indoor light conditions, it can produce a synergistic catalytic effect with calcium manganese silicon materials, further improving the purification efficiency.

[0013] The organic binder and the plant polyphenol crosslinking agent work together to provide the coating with the necessary mechanical strength and toughness. More importantly, they form a moderately crosslinked polymer network rich in hydrophilic groups and with microchannels. This network can stably disperse functional materials while allowing water molecules and ions to pass through, providing the necessary pathways and driving forces for the migration of functional materials.

[0014] In summary, the reinforced putty layer, the penetrating and reinforcing primer layer, and the purifying topcoat layer constitute an organic whole. The putty layer and the primer layer form a stable alkaline porous substrate, which is conducive to maintaining the ion balance and humidity buffering of the topcoat layer network; the topcoat layer itself constructs a microcirculation system that supports the directional migration of functional materials. This system-level design ensures the long-term effectiveness of the purification function.

[0015] The present invention also provides a core purification function topcoat composition for the coating system, a continuous hydrothermal synthesis method for the calcium manganese silicon composite functional material, a preparation method for the purification function topcoat composition, and a building using the coating system.

[0016] The beneficial effects of this invention are that by designing a migratory calcium-manganese-silicon composite functional material with a specific structure and combining it with a three-layer coating structure that supports migration, the active catalytic components are dynamically replenished from the inside of the coating to the surface. This helps overcome the shortcomings of traditional fixed catalysts, which are prone to deactivation, and improves the durability of the purification function. Each layer and component produces a synergistic effect through precise coordination. As shown in the examples, the coating system of this invention has a high initial formaldehyde purification rate, and its 28-day purification durability is significantly better than the comparative example, demonstrating the system's long-lasting advantage. It also possesses excellent adhesion, humidity regulation, and antibacterial properties. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto.

[0018] Example 1: Preparation of calcium-manganese-silicon composite functional materials

[0019] 74.1 g of calcium hydroxide, 34.8 g of electrolytic manganese dioxide, and 30.0 g of highly active nano-rice husk ash were weighed and added to a reaction vessel containing 500 mL of deionized water. The mixture was stirred to form a homogeneous slurry. The slurry was transferred to a high-pressure reactor and reacted at 180 °C for 8 hours. After the reaction, the mixture was cooled, and the resulting slurry was spray-dried at an inlet temperature of 220 °C and an outlet temperature of 85 °C to obtain a light brown powder. X-ray diffraction analysis showed that the product spectrum simultaneously exhibited characteristic peaks of layered calcium silicate and manganese potassium oxide-type manganese dioxide, confirming a two-phase composite structure. X-ray fluorescence spectroscopy analysis indicated that the manganese content in the material was 12.1% by weight, and the molar ratio of calcium to silicon was 1.83:1.

[0020] Example 2: Preparation of Purifying Functional Topcoat Composition

[0021] Raw material ratio: 120 parts by weight of the above-mentioned calcium manganese silicon composite functional material; 80 parts by weight of attapulgite clay modified with silane coupling agent KH-550 (its micropore diameter is about 1.0 nm and its mesopore diameter is about 30 nm); 40 parts by weight of titanium dioxide powder with a cerium doping amount of 1.2 atomic percentage; 90 parts by weight of white silicate cement; 30 parts by weight of gray calcium; 40 parts by weight of metakaolin; 120 parts by weight of silicone acrylic emulsion with a glass transition temperature of 15℃; 60 parts by weight of aqueous solution (dry weight) of starch-acrylic monomer graft copolymer with a grafting rate of 20%; 10 parts by weight of tannic acid; 5 parts of polycarboxylate dispersant; 2 parts of mineral oil defoamer; 1.5 parts of hydroxyethyl cellulose thickener; and 150 parts of deionized water.

[0022] Preparation process:

[0023] (1) Add deionized water, dispersant, defoamer and all powder raw materials to the dispersion tank, and disperse at a high speed of 1200 rpm at a temperature below 45°C until the slurry fineness D90 is 45 microns. (2) Reduce the speed to 800 rpm, control the system temperature to 38°C, and slowly add silicone acrylic emulsion, starch graft copolymer solution and pre-prepared lime slurry.

[0024] (3) Add tannic acid and thickener, transfer to a curing tank, and cure by stirring at 30°C and 15 rpm for 2.5 hours. Adjust the viscosity to 102 KU and the pH to 8.5 by monitoring with an online rotational viscometer to obtain the topcoat composition.

[0025] Example 3: Coating System Application and Performance Testing

[0026] The substrate was a standard cement mortar test board. Construction process: ① Apply a water-resistant putty layer with sulfoaluminate cement as the binder and let it dry; ② Apply a penetrating reinforcing primer containing 35% silane-modified silica sol by roller and let it dry to the surface; ③ Apply the topcoat composition obtained in Example 2, with a dry film thickness of 1.8 mm, and cure for 7 days under standard conditions to form a complete coating system.

[0027] Performance test results:

[0028] Formaldehyde purification performance was tested according to JC / T 1074-2008: 24-hour purification rate was 94.2%, and 28-day purification durability was 88.5%.

[0029] The adhesion was tested according to GB / T 5210-2006: 2.53 MPa.

[0030] Humidity conditioning performance was tested according to JIS A 1470-1:2008: 27.8 g / m².

[0031] The antibacterial performance was tested according to GB / T 21866-2008: the antibacterial rate against Staphylococcus aureus was 99.94%.

[0032] The limit for hazardous substances was tested according to GB 18582-2020: VOC content was 1.2 g / L.

[0033] To investigate the mechanism of long-term purification of the system, cross-sectional analysis was performed on the coating samples after a 28-day purification durability test. Scanning electron microscopy combined with X-ray energy dispersive spectroscopy was used for line scanning analysis of the coating cross-section. The results showed that compared with the unused initial coating, the ratio of manganese signal intensity to calcium in the 0-50 micrometer depth region of the sample surface increased by an average of approximately 18%, while this ratio decreased accordingly in the 100-200 micrometer depth region of the middle of the topcoat layer. This gradient change in elemental distribution indicates that during long-term use, the manganese active component in the calcium-manganese-silicon composite functional material did indeed undergo directional migration from the interior of the coating to the surface, thereby continuously replenishing the catalytic active sites on the surface. This phenomenon confirms the effectiveness of the hydrophilic transport channel jointly constructed by the penetrating and reinforcing primer layer and the purification functional topcoat layer, and directly explains the intrinsic reason for the high durability of the system's purification performance.

[0034] Example 4: Continuous Production of Calcium-Manganese-Silicon Composite Functional Materials

[0035] A tubular continuous hydrothermal reaction system was employed. Calcium hydroxide, manganese sulfate, and silica sol were mixed in a calcium:manganese:silicon molar ratio of 5:2:3 to form a homogeneous slurry with a solid content of 30%. This slurry was pumped into a preheated tubular reactor at a constant flow rate using a high-pressure pump. The reaction zone temperature was controlled at 180℃, the pressure at 2.0 MPa, and the average residence time at 8 hours. The effluent was spray-dried to obtain a powder product. After 24 hours of continuous operation, sampling and analysis showed that the manganese content of the product ranged from 11.8% to 12.3% by weight, and the calcium:silicon molar ratio fluctuated between 1.95 and 2.05, indicating good stability.

[0036] Example 5: Industrial preparation of topcoat composition

[0037] Production takes place in a 5000-liter reactor equipped with a distributed control system. Strict process control is followed according to Example 2, with key control measures including ensuring the material temperature does not exceed 45°C during the dispersion stage and that the slurry fineness (D90) is no greater than 50 micrometers before automatic transfer to the next process. During the maturation stage, a closed-loop viscosity control system is achieved through an online viscometer interlocked with a pure water addition system, ensuring that the viscosity of each batch of finished product remains stable within 101-103 KU.

[0038] Comparative Example 1

[0039] Equal masses of calcium hydroxide, electrolytic manganese dioxide, and nano-rice husk ash powders were mixed using a simple mechanical dry method to replace the hydrothermally synthesized calcium-manganese-silicon composite functional material in Example 2. All other raw materials and processes remained identical. The resulting coating achieved an initial formaldehyde purification rate of 82.0%. To simulate the consumption of active sites, the coated sample was subjected to a cyclic test involving immersion in deionized water for 12 hours and drying at 60°C for 12 hours. After 5 cycles, the purification efficiency dropped sharply to 33.7%.

[0040] Comparative Example 2

[0041] The topcoat composition obtained in Example 2 was directly applied to the cement mortar board, omitting the reinforcing putty layer and the penetrating reinforcing primer layer. Its 28-day formaldehyde purification durability was tested at 78.2%, significantly lower than the 88.5% of Example 3.

[0042] Comparative Example 3

[0043] In the formulation of Example 2, the tannic acid crosslinking agent was omitted, and the starch graft copolymer was replaced with an equal amount of hydroxypropyl methylcellulose. The penetrating primer was also replaced with a regular acrylic primer. After 30 days of accelerated aging testing, the formaldehyde purification durability of the resulting coating was only 71.5%.

[0044] The above embodiments and comparative examples demonstrate that the specific composition, structure, and preparation method of the coating system of the present invention are necessary and inseparable for realizing the functions of "dynamic migration and regeneration" and "long-term purification".

[0045] The scope of protection of this invention is defined by the claims. Any modifications based on the inventive concept should fall within the scope of protection of this invention.

Claims

1. A building interior wall purification coating system having a dynamic migration regeneration function, characterized in that, The coating comprises, from inside to outside, a reinforced putty layer, a penetrating reinforced primer layer and a purification functional topcoat layer which are successively applied on a building substrate; wherein the reinforced putty layer comprises, by dry film weight percentage, 30-60% of water-resistant inorganic cementitious material, 20-50% of aggregate, 0.1-2% of reinforcing fiber, and the balance of water and auxiliaries; the penetrating reinforced primer layer comprises, by dry film weight percentage, 20-50% of silane-modified silica sol, and the balance of water and alcohol solvent; the purification functional topcoat layer comprises, by dry film weight percentage, 8-15% of calcium-manganese-silicon composite functional material, 5-10% of adsorbent material with bimodal pore size distribution, 2-6% of cerium-doped titanium dioxide, 15-30% of inorganic cementitious material, 10-25% of organic adhesive film-forming substance, 0.5-3% of plant polyphenol crosslinking agent, and the balance of water, dispersant, thickening agent, defoaming agent and pH regulator; wherein the calcium-manganese-silicon composite functional material has a composite phase structure of layered calcium silicate and manganese potassium ore type manganese dioxide, and the manganese element content is 9.0-15.0%, and the molar ratio of calcium element to silicon element is 1.6:1-2.1:1, based on the total weight of the calcium-manganese-silicon composite functional material; the adsorbent material contains both micropores and mesopores, wherein the micropore size is 0.8-1.2 nanometers, and the mesopore size is 20-50 nanometers; in the cerium-doped titanium dioxide, the atomic doping amount of cerium element is 0.5-2.0%; the organic adhesive film-forming substance contains a silicone-acrylic emulsion with a glass transition temperature of 10-20℃, and a graft copolymer of starch and acrylic monomer with a grafting rate of 15-25%; the plant polyphenol crosslinking agent is tannic acid; and the inorganic cementitious material contains lime.

2. The architectural interior wall coating system with dynamic migration and regeneration according to claim 1, wherein, The calcium-manganese-silicon composite functional material is prepared by a hydrothermal method comprising the following steps: mixing a calcium source, a manganese source and an active silicon source in a molar ratio of calcium, manganese and silicon of 4.5-5.5:1.5-2.5:2.5-3.5, and hydrothermally reacting at 160-200℃ under a pressure of 1.5-2.5MPa for 6-12 hours, and then drying the obtained product to obtain.

3. The architectural interior wall coating system with dynamic migration and regeneration according to claim 1, wherein, The adsorbent material is attapulgite or diatomite which is surface-modified by a silane coupling agent.

4. The architectural interior wall coating system with dynamic migration and regeneration according to claim 1, wherein, The water-resistant inorganic cementitious material is sulphoaluminate cement or high-alumina cement.

5. A washcoat composition for use in the construction of a wall in-building purification coating system according to claim 1, characterized in that, The following raw materials are mixed, dispersed and matured to obtain: Calcium-manganese-silicon composite functional material 80-150 parts by weight; Adsorbent material with bimodal pore size distribution 50-100 parts by weight; Cerium-doped titanium dioxide 20-60 parts by weight; Inorganic cementitious material 110-230 parts by weight; Organic adhesive film-forming substance 110-230 parts by weight; Plant polyphenol crosslinking agent 5-20 parts by weight; and the balance of water, dispersant, thickening agent, defoaming agent and pH regulator, totaling 155-300 parts by weight; wherein, The calcium-manganese-silicon composite functional material has a composite phase structure of layered calcium silicate and manganite-type manganese dioxide, and contains 9.0-15.0% of manganese element by weight, and the molar ratio of calcium element to silicon element is 1.6:1-2.1:1; The adsorbing material contains micropores and mesopores, wherein the micropore size is 0.8-1.2 nm, and the mesopore size is 20-50 nm; In the cerium-doped titanium dioxide, the atomic doping amount of cerium element is 0.5-2.0%; The inorganic cementitious material is selected from one or more of white Portland cement, calcium carbonate, and metakaolin; The organic adhesive film-forming material contains a silicone-acrylate emulsion with a glass transition temperature of 10-20℃, and a graft copolymer of starch and acrylate monomers with a grafting rate of 15-25%.

6. A continuous hydrothermal synthesis method for preparing the calcium-manganese-silicon composite functional material of claim 2, characterized in that, The method comprises the following steps: S1. Preparing a homogeneous slurry with a solid content of 25-35% from a calcium source, a manganese source, and an active silicon source; S2. Pumping the slurry into a continuous hydrothermal reactor, and keeping it at 175-185℃ and a pressure of 1.8-2.2 MPa for 6-10 hours; S3. Spraying and drying the reaction product, and controlling the inlet temperature to be 210-230℃ and the outlet temperature to be 80-90℃, to obtain the calcium-manganese-silicon composite functional material in powder form.

7. A method of preparing the purifying functional finish composition of claim 5, characterized by, The method comprises the following sequential steps: (1). Powder dispersion: dispersing all the powder raw materials in a liquid medium at a temperature not higher than 45℃ and a rotation speed of 1000-1500 rpm until the fineness D90 of the slurry is ≤50 microns; (2). Emulsion mixing: reducing the rotation speed to 600-900 rpm, controlling the system temperature to be 35-40℃, and sequentially adding the silicone-acrylate emulsion, the graft copolymer of starch and acrylate monomers, and calcium carbonate, with the temperature rise of the system controlled to be not more than 8℃ during the adding process; (3). Maturation and viscosity adjustment: adding the plant polyphenol crosslinking agent and other additives, stirring and maturing at 25-35℃ and a rotation speed of 5-20 rpm for 1.5-3 hours, and monitoring and closed-loop controlling the addition amount of the adjusting liquid through an online viscometer during the process, so that the viscosity of the final product reaches 100-105 KU.

8. A building, characterized in that The inner wall surface is provided with the building inner wall purification coating system according to any one of claims 1 to 4.