A mica-based aqueous slurry composition

Abstract

This invention provides a mica-based aqueous slurry composition, relating to the field of insulating and heat-insulating materials. It comprises 60%–80% mica powder, 15%–30% aqueous binder, 1%–5% dispersant, 0.5%–3% short fiber material, and 2%–8% deionized water. The composition is a uniform and stable suspension with a Ford cup viscosity of 20s–40s, and shows no stratification or sedimentation after standing for 72 hours. Through reasonable formulation and optimized preparation process, the problems of uneven dispersion, poor stability, insufficient environmental friendliness, and weak coating adhesion of existing slurries are solved. It features uniform dispersion, good stability, environmental friendliness, energy saving, and convenient construction.

Description

Technical Field

[0001] This invention relates to the field of insulating and heat-insulating materials, and in particular to a mica-based aqueous slurry composition. Background Technology

[0002] Currently, most spray coatings used for insulating and heat-insulating coatings on metal substrates use organic resins as the base material and mica powder as an auxiliary filler. These coatings suffer from poor dispersion uniformity, insufficient stability, and poor environmental performance. Some coatings lack dispersants or use inappropriate dispersants, leading to mica powder agglomeration, resulting in poor coating density and high porosity after spraying. This severely affects the insulation and heat-insulating performance and makes the coating prone to pinholes and sagging defects. Furthermore, existing coatings often lack reinforcing components, resulting in insufficient adhesion and strength after spraying. Long-term use leads to cracking and peeling, shortening the service life of metal components. Traditional methods of heat insulation treatment for metal parts using mica boards, mica backing boards, and mica paper wrapping are not only complex processes but also have weak bonding strength and environmental problems.

[0003] Furthermore, existing water-based spray coating slurries suffer from the drawback of difficulty in viscosity control. High viscosity can easily lead to spray gun clogging, while low viscosity can cause sagging, both affecting construction efficiency and coating quality. Some slurries have stringent requirements for the purity and particle size of mica raw materials, significantly increasing raw material procurement costs and making them unsuitable for large-scale industrial production. Existing mica-based spray coating slurry compositions cannot simultaneously achieve good dispersibility, stability, environmental friendliness, and coating performance, failing to meet the stringent requirements for insulation and thermal protection of metal components in the new energy and energy storage sectors. Therefore, developing a mica-based water-based slurry composition that is uniformly dispersed, stable, environmentally friendly, energy-saving, and can improve coating adhesion and strength has become a pressing technical problem for the industry.

[0004] In the prior art, Chinese patent CN117659811B (Anhui Shenjian New Material Co., Ltd.) discloses a fire-retardant and insulating powder coating for metal substrates and its preparation method. This prior art is a powder coating, which requires high-temperature curing, resulting in high energy consumption, poor environmental performance, and the use of mica powder as an auxiliary filler without the addition of short fibers, leading to insufficient coating strength. Chinese patent CN116656194B (Anhui Zuoyan Chemical Technology Co., Ltd.) discloses an aerogel composite high-temperature resistant fire-retardant coating, which uses acrylic emulsion as a base material without the addition of short fibers, resulting in insufficient coating strength and poor slurry dispersibility and stability, easily leading to agglomeration and delamination. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a mica-based spraying slurry that is uniformly dispersed, highly stable, environmentally friendly, and energy-saving.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a mica-based water-based slurry composition, which, by mass percentage, is composed of the following components mixed together: 60%–80% mica powder, 15%–30% water-based binder, 1%–5% dispersant, 0.5%–3% short fiber material, and 2%–8% deionized water; the composition is a uniform and stable suspension with a Ford cup viscosity of 20s–40s, and exhibits no stratification or sedimentation after standing for 72 hours, making it suitable for air spraying, airless spraying, and electrostatic spraying.

[0007] Furthermore, the mica powder is natural mica powder or modified mica powder, with a particle size of 325 mesh to 1250 mesh; the modified mica powder is silane coupling agent modified mica powder, and the amount of silane coupling agent added is 0.1% to 0.5% of the mass of mica powder, which can further improve the compatibility of mica powder with water-based binders and reduce agglomeration.

[0008] Furthermore, the water-based adhesive is one or more of water-based silicate adhesive, water-based acrylic adhesive, or water-based polyurethane adhesive; wherein, when water-based silicate adhesive and water-based acrylic adhesive are used in combination, the mass ratio is 1:1 to 3, which can take into account both the insulation performance and flexibility of the coating and avoid coating cracking.

[0009] Furthermore, the dispersant is a polycarboxylate dispersant or a lignin sulfonate dispersant, preferably a polycarboxylate dispersant, which has excellent dispersing effect, can effectively prevent mica powder agglomeration, improve slurry stability, and has good compatibility with water-based systems, without affecting the coating insulation performance.

[0010] Furthermore, the short fiber material is one or more of glass short fibers, carbon fibers, or basalt short fibers, with a length of 0.1 mm to 1 mm. It is uniformly dispersed in the slurry, which can enhance the strength and crack resistance of the coating after spraying and improve the adhesion between the coating and the metal substrate. The short fiber material needs to be pretreated with a silane coupling agent for 10 min to 20 min, and then dried before use, which can improve the adhesion between the short fiber and other components.

[0011] Furthermore, the slurry composition may also contain 0.1% to 0.5% of a defoamer, which is an organosilicon defoamer, to effectively eliminate bubbles generated during slurry preparation and prevent pinhole defects in the coating after spraying; the slurry composition may also contain 0.1% to 0.3% of a leveling agent to improve the leveling properties of the slurry and prevent phenomena such as sagging and orange peel during spraying.

[0012] Compared with the prior art, the present invention has the following significant advantages: 1. Uniform dispersion and excellent stability: By rationally selecting dispersants and optimizing the ratio, combined with precise stirring process, the agglomeration of mica powder is effectively prevented, ensuring uniform dispersion of the slurry. After standing for 72 hours, there is no layering or sedimentation, and the slurry has good storage stability, making it convenient to store and use. This avoids spray gun clogging or coating defects caused by slurry agglomeration.

[0013] 2. Environmentally friendly and energy-saving, with high safety: It adopts a fully water-based system with no harmful solvents added, making it environmentally friendly and odorless. There are no harmful gas emissions during the preparation and spraying process, which is in line with the concept of green production. It does not require high-temperature sintering and is suitable for low-temperature drying or natural drying, resulting in low energy consumption and reducing environmental pressure and safety hazards in the production process.

[0014] 3. Excellent coating performance: The addition of short fiber materials, combined with the insulating and heat-insulating properties of mica powder, not only significantly improves the adhesion, strength, and crack resistance of the coating after spraying, preventing the coating from cracking and peeling, but also fully utilizes the insulating and heat-insulating advantages of mica powder, ensuring that the coating volume resistivity is ≥10¹²Ω·cm and the thermal conductivity is ≤0.15W / (m·K), meeting the insulation and heat-insulating requirements of new energy and energy storage fields.

[0015] 4. Convenient construction and strong adaptability: The viscosity is precisely controlled between 20s and 40s, and it is compatible with various spraying methods such as air spraying, airless spraying, and electrostatic spraying. There is no gun clogging or sagging during the spraying process, and the construction efficiency is high. It can be used for various metal components such as flat and irregular shapes, and has moderate requirements for mica raw materials. The raw material cost is low, and it can achieve large-scale production.

[0016] 5. Good compatibility and strong adjustability: The proportion of each group can be flexibly adjusted according to different usage scenarios to adapt to the preparation of coatings with different thicknesses and performance requirements. At the same time, it can be well bonded to various roughened metal substrates, making it widely applicable. Detailed Implementation

[0017] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments. Example

[0018] A mica-based aqueous slurry composition, by mass percentage, comprises the following components: 70% natural mica powder (600 mesh), 22% aqueous silicate binder (Jiyesheng water glass with a Baume degree of 45%), 3% polycarboxylate dispersant (JHX-2000), 0.5% glass short fibers (0.5 mm in length, surface-treated with epoxy silane KH-560, first prepared as a 0.5%–2% aqueous solution of coupling agent, adjusted to pH 4–5, impregnated for 10 min, and then dried at 120°C for 2 hours), and 4.5% deionized water.

[0019] Preparation method: Add 4.5 parts of deionized water to a high-speed disperser, turn on the stirrer, and control the speed at 400 r / min. Add 3 parts of polycarboxylate dispersant and 22 parts of waterborne silicate binder in sequence, and stir for 15 min to fully dissolve and mix them. Then slowly add 70 parts of natural mica powder and 0.5 parts of pretreated glass short fibers, increase the speed to 1000 r / min, and use intermittent stirring (stop for 5 min every 20 min of stirring) for a total stirring time of 45 min. Adjust the viscosity to 30s at the Forecast cup 4 to obtain the mica-based waterborne slurry composition.

[0020] Tests showed that the slurry composition exhibited no stratification or sedimentation after standing for 72 hours, and was uniformly dispersed. Example

[0021] A mica-based aqueous slurry composition, by mass percentage, comprises the following components: 65% modified mica powder (800 mesh, modified with silane coupling agent), 28% aqueous acrylic binder (Wanhua Chemical WH-8020), 2% lignin sulfonate dispersant (Marasperse® C-20), 1% carbon fiber (0.8 mm, surface-treated with epoxy silane KH-560 for glass short fibers, first prepared as a 0.5%–2% aqueous solution of coupling agent, adjusted to pH 4–5, impregnated for 15 min, and then dried at 120°C for 2 hours), 4% deionized water, 0.2% organosilicon defoamer (Evonik Foamex® 888), and 0.2% leveling agent (Dow Corning® 8620).

[0022] Preparation method: Add 4 parts of deionized water to a high-speed disperser, start stirring, and control the speed at 500 r / min. Add 2 parts of lignin sulfonate dispersant and 28 parts of water-based acrylic binder in sequence, and stir for 10 min to fully dissolve and mix them. Then slowly add 65 parts of modified mica powder and 1 part of pretreated carbon fiber, increase the speed to 1200 r / min, and use intermittent stirring (stop for 5 min every 20 min of stirring), with a total stirring time of 30 min. Finally, add 0.2 parts of organosilicon defoamer and 0.2 parts of leveling agent, continue stirring for 8 min, and adjust the viscosity to 35 s at the Forecast 4 cup to obtain the mica-based water-based slurry composition.

[0023] Tests showed that the slurry composition exhibited no stratification or sedimentation after standing for 72 hours, demonstrating excellent stability. Example

[0024] A mica-based aqueous slurry composition, by mass percentage, comprises the following components: 75% natural mica powder (400 mesh), 18% aqueous polyurethane binder (WH-PU100), 4% polycarboxylate dispersant (JHX-2000), 1% basalt short fibers (0.3 mm, surface treated with epoxy silane KH-560, first prepared as a 0.5%–2% aqueous solution of coupling agent, adjusted to pH 4–5, impregnated for 10 min, and then dried at 110°C for 2 hours), 2% deionized water (tertiary or secondary grade), and 0.1% silicone defoamer (Foamex® 888).

[0025] Preparation method: Add 2 parts of deionized water to a high-speed disperser, start stirring, and control the speed at 300 r / min. Add 4 parts of polycarboxylate dispersant and 18 parts of waterborne polyurethane binder in sequence, and stir for 20 min to fully dissolve and mix them. Then slowly add 75 parts of natural mica powder and 1 part of pretreated basalt short fibers, increase the speed to 800 r / min, and use intermittent stirring (stop for 5 min every 20 min of stirring), with a total stirring time of 60 min. Finally, add 0.1 parts of organosilicon defoamer, continue stirring for 5 min, and adjust the viscosity to 25 s of Forecast cup 4 viscosity to obtain the mica-based waterborne slurry composition.

[0026] Tests showed that the slurry composition exhibited no stratification or sedimentation after standing for 72 hours, demonstrating good dispersibility.

[0027] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A mica-based aqueous slurry composition, characterized in that, The slurry composition comprises the following components by weight percentage: 60%–80% mica powder, 15%–30% aqueous binder, 1%–5% dispersant, 0.5%–3% short fiber material, and 2%–8% deionized water.

2. The mica-based aqueous slurry composition according to claim 1, characterized in that, The composition is a uniform and stable suspension with a viscosity of 20s to 40s in a Ford cup and no stratification or precipitation after standing for 72 hours.

3. The mica-based aqueous slurry composition according to claim 1, characterized in that, The mica powder is natural mica powder or modified mica powder, with a particle size of 325 mesh to 1250 mesh.

4. The mica-based aqueous slurry composition according to claim 3, characterized in that, The modified mica powder is a silane coupling agent modified mica powder, and the amount of silane coupling agent added is 0.1% to 0.5% of the mass of mica powder.

5. The mica-based aqueous slurry composition according to claim 1, characterized in that, The water-based adhesive is one or more of water-based silicate adhesive, water-based acrylic adhesive, or water-based polyurethane adhesive; when water-based silicate adhesive and water-based acrylic adhesive are used in combination, the mass ratio is 1:1 to 3.

6. The mica-based aqueous slurry composition according to claim 1, characterized in that, The dispersant is a polycarboxylate dispersant or a lignin sulfonate dispersant.

7. The mica-based aqueous slurry composition according to claim 6, characterized in that, The dispersant is a polycarboxylate dispersant.

8. The mica-based aqueous slurry composition according to claim 1, characterized in that, The short fiber material is one or more of glass short fibers, carbon fibers or basalt short fibers, with a length of 0.1 mm to 1 mm; the short fiber material is pretreated with a silane coupling agent for 10 min to 20 min.

9. The mica-based aqueous slurry composition according to claim 1, characterized in that, It also includes 0.1% to 0.5% of silicone defoamer and / or 0.1% to 0.3% of leveling agent.