A high-permeability crystalline microporous honeycomb-like breathable cement-based protective dry powder paint and a preparation method thereof

Abstract

This invention discloses a cement-based protective dry powder coating based on high-permeability crystallization and honeycomb microporous breathing structure and its preparation method. This invention solves the industry problems of water seepage, efflorescence, and mold growth on walls in humid environments, simplifies the construction process, improves the long-term effectiveness and applicability of protective materials, and lowers the barriers to transportation and construction of traditional protective coatings.

Description

Technical Field

[0001] This invention relates to the field of building protection materials technology, and in particular to a high-permeability crystalline microporous honeycomb breathable cement-based protective dry powder coating and its preparation method. Background Technology

[0002] The walls of medical institutions such as clinics and community health centers, as well as building walls in damp environments like basements and bathrooms, often face persistent problems such as water seepage, efflorescence, efflorescence, and mold growth. These issues not only affect the aesthetics and lifespan of the walls but can also potentially endanger human health. While traditional organic latex paints are aesthetically pleasing, they tend to form a "sealed film" in damp environments, preventing moisture from escaping and creating osmotic pressure that causes the paint film to peel and blister, failing to fundamentally solve the dampness problem.

[0003] To address this issue, cement-based penetrating crystalline waterproofing materials are widely used, but their hard texture makes them prone to cracking and their poor decorative properties, failing to meet practical construction and usage requirements. Ordinary inorganic coatings are mostly liquid, inconvenient for long-distance transportation and storage, and require strict application techniques, with stringent control over the moisture content of the substrate, increasing construction costs and difficulty. Therefore, developing a single-component, breathable, efflorescence-resistant, and micro-crack-repairing cement-based dry powder protective material has become an urgent need in the field of building protection. Summary of the Invention

[0004] One objective of this invention is to provide a high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating and its preparation method. This invention solves the problems of traditional protective coatings being prone to peeling, efflorescence, and mold growth in humid environments, reduces the barriers to construction and transportation, and improves the longevity and applicability of protective materials.

[0005] According to an embodiment of the present invention, a high-permeability crystalline microporous honeycomb breathable cement-based protective dry powder coating is a single-component powder mixture. During application, water is added at a water-cement ratio of 0.30-0.45 and stirred to form a paste. By weight, its raw material composition includes: 40.0-55.0 parts of ordinary silicate cement, 6.0-12.0 parts of cellulose-modified bentonite, 2.5-7.5 parts of plant-derived modified adhesive powder, 4.0-9.0 parts of active soft fiber filaments loaded with calcium hydroxide, 8.0-15.0 parts of cement-based penetrating crystalline waterproof masterbatch, 10.0-20.0 parts of nano-grade active silica-alumina powder filler, and 0.5-2.0 parts of powder crack-resistant reinforcing agent. Its preparation method includes three steps: premixing, modified composite, and fiber implantation. It is ready to use immediately after mixing, making application convenient.

[0006] The beneficial effects of this invention are: 1. Completely blocks efflorescence and mold: The honeycomb microporous structure has excellent air permeability and moisture wicking performance, which destroys the moisture conditions required by mold. At the same time, the active soft fiber filaments loaded with calcium hydroxide keep the coating strongly alkaline (pH>11), inhibiting the germination of mold spores from a biochemical level, neutralizing acidic substances to prevent efflorescence, and solving the stubborn problem of walls in humid environments. 2. Convenient construction: It adopts a single-component dry powder form, which is convenient for transportation and storage. It can be mixed with water to form a paste for construction. No complicated equipment is required. The moisture content of the construction substrate can be relaxed to more than 15%, which reduces the construction threshold and cost. 3. Deep self-healing and long-lasting waterproofing: It has a high-penetration crystallization function, and the active chemical substances can penetrate deep into the wall to generate insoluble crystals, automatically repairing micro-cracks within 0.4 mm in the substrate and achieving deep sealing; 4. Long service life: It is homogeneous with mineral substrates and will not blister or peel off. Its service life is synchronized with that of the wall, which improves the long-term effectiveness of building protection and has great application and promotion value. Attached Figure Description

[0007] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating the preparation method of a high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating proposed in this invention. Detailed Implementation

[0008] Example 1: A high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating, by weight, comprises: 50.0% ordinary silicate cement (PO 42.5), 8.0% cellulose-modified bentonite, 4.0% plant-derived modified adhesive powder, 6.0% active soft fiber filaments loaded with calcium hydroxide, 12.0% cement-based penetrating crystalline waterproof masterbatch, 18.0% nano-grade active silica-alumina powder filler, and 2.0% powder crack-resistant reinforcing agent.

[0009] The preparation method includes the following steps: (1) Premixing: Put ordinary silicate cement and nano-grade active silica-alumina powder filler into a mixer and stir for 12 minutes to ensure uniform mixing; (2) Modification and composite: Add cellulose-modified bentonite, plant-derived modified adhesive powder and cement-based penetrating crystalline waterproof masterbatch, and continue dry mixing for 8 minutes to fully composite each component; (3) Fiber implantation: Finally, add active soft fiber filaments loaded with calcium hydroxide, use variable frequency low-speed stirring (200 rpm), stir for 5 minutes to prevent fiber bundle breakage or excessive wear, and obtain the finished dry powder coating.

[0010] The application method is as follows: When constructing, pour the dry powder coating and clean water into a container at a ratio of powder:water = 1:0.38, stir thoroughly until it becomes a fine paste, let it stand for 5 minutes, stir it again, and then apply it by scraping. The thickness of the scraping should be controlled at 1.5-2.0mm. The moisture content of the substrate should be 18%. The best protective effect can be achieved after curing for 7 days after construction.

[0011] Experimental tests show that the coating prepared in this example has a water-resistant pressure of 1.4 MPa (meeting GB / T 18445 standard) and an air permeability of 185 g / m³. 2 • After 24 hours (compliant with ASTM E96 standard), the mildew resistance rating is 0 (no growth, compliant with GB / T 1741 standard). After 240 hours of saturated alkali immersion, there is no salt precipitation or abnormality. The microstructure is a regular nano-honeycomb micropore. Its comprehensive performance is superior to ordinary cement waterproof coatings.

Claims

1. A high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating, characterized in that, include: This coating is a single-component powder mixture. During application, water is added at a water-cement ratio of 0.30-0.45 and stirred into a paste. By weight, its raw material composition includes: 40.0-55.0 parts of ordinary silicate cement, 6.0-12.0 parts of cellulose-modified bentonite, 2.5-7.5 parts of plant-derived modified adhesive powder, 4.0-9.0 parts of active soft fiber filament loaded with calcium hydroxide, 8.0-15.0 parts of cement-based penetrating crystalline waterproof masterbatch, 10.0-20.0 parts of nano-grade active silica-alumina powder filler, and 0.5-2.0 parts of powder crack-resistant reinforcing agent.

2. The high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating according to claim 1, characterized in that, The ordinary Portland cement used is Portland cement with a strength grade of PO 42.5 or PO 52.5, and its specific surface area is controlled at 320-350 m². 2 / kg.

3. The high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating according to claim 2, characterized in that, The cellulose-modified bentonite is formed by high-energy ball milling and coating sodium bentonite and hydroxypropyl methylcellulose (HPMC) in a mass ratio of 10:1-15:1; it plays a thixotropic thickening role in the system and helps to form a nanoscale honeycomb channel template.

4. The high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating according to claim 3, characterized in that, The plant-derived modified adhesive powder is a derivative of guar gum or guar gum. After being mixed with water, it forms a viscoelastic polymer gel network, which is used to improve the water retention of cementitious substrates and provide early bonding strength.

5. The high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating according to claim 1, characterized in that, The active soft fiber filament loaded with calcium hydroxide has an alkali-resistant synthetic fiber core and an active Ca(OH)2 micro powder loaded on the surface; it acts as both a physical reinforcing rib and a pH buffer in the coating to prevent alkali efflorescence on the substrate.

6. The high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating according to claim 5, characterized in that, The cement-based penetrating crystalline waterproof masterbatch contains active chemical substances that can penetrate into the interior of the wall with water and react with cement hydration products to generate insoluble crystals (such as needle-shaped ettringite), thus achieving deep sealing.

7. The high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating according to claim 6, characterized in that, After curing and drying, the coating forms a honeycomb microporous structure with an average pore size between 30 and 55 nm. This structure has selective permeability between gas and liquid phases, ensuring that the coating is breathable but not water-permeable.

8. The high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating according to claim 7, characterized in that, A method for preparing a coating as described in any one of claims 1-7, comprising the following steps: (1) premixing: ordinary silicate cement and nano-grade filler are put into a mixer and stirred for 10-15 minutes; (2) modified composite: cellulose-modified bentonite, plant-derived rubber powder and waterproof masterbatch are added and dry-mixed; (3) fiber implantation: finally active soft fiber filaments are added and frequency-controlled low-speed stirring (150-300 rpm) is used to prevent fiber bundle breakage or excessive wear.

9. The high-penetration crystalline microporous honeycomb breathable cement-based protective dry powder coating according to claim 8, characterized in that, A method for applying the coating as described in any one of claims 1-7: During construction, the dry powder is poured into clean water and stirred thoroughly until it becomes a paste. After standing for 5 minutes, it is stirred again before application. The moisture content of the substrate can be relaxed to over 15%.

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