A MoS2 slurry, coating and its preparation method

Abstract

This invention relates to the field of coating slurry technology, specifically to a MoS2 slurry, coating, and its preparation method. The MoS2 slurry comprises the following raw materials by weight percentage: 20% nanosheet MoS2 dispersion, 60-80% aqueous polyurethane resin, and additives; the nanosheet MoS2 dispersion comprises the following raw materials by weight percentage: 5-15% MoS2 powder, 5-15% dispersant, and 70-90% solvent, wherein the solvent includes propylene glycol and water. This slurry contains a nanosheet MoS2 dispersion, exhibiting excellent wear resistance and flexural strength. The nanosheet MoS2 dispersion is prepared by using MoS2 powder and a solvent containing propylene glycol, with propylene glycol used as an exfoliating solvent. The prepared dispersion can be directly used to mix the MoS2 slurry without drying it into a solid, effectively improving work efficiency.

Description

Technical Field

[0001] This invention relates to the field of coating slurry technology, specifically to a MoS2 slurry, coating, and preparation method thereof. Background Technology

[0002] Everyday athletic shoes need to be lightweight, comfortable, and breathable, and mesh is often used as the upper material for running shoes and training shoes. Sandwich mesh, a commonly used upper material, is mostly made of textiles or polyester. In addition to being lightweight, comfortable, and breathable, it can also be water-repellent, anti-wicking, and oil-repellent. However, it does not have abrasion resistance or scratch resistance, which limits its application in competitive sports.

[0003] To enhance the abrasion resistance of shoe upper mesh, abrasion-resistant substances, such as wax powder or abrasive powder, can be added to the surface coating of the mesh. For example, Chinese invention patent application number 201910953933.5 discloses a white fused alumina waterborne polyurethane coating and its preparation and application. The white fused alumina waterborne polyurethane coating provided uses a rigid abrasion-resistant material—white fused alumina modified waterborne polyurethane—as a basis. Footwear, accessories, or clothing made of polyester or nylon mesh coated with this material exhibits extremely high abrasion resistance and scratch resistance, is soft and durable, and provides maximum comfort. While this method can improve the overall abrasion resistance of the fabric, it generally suffers from a decrease in the overall coating's bending resistance, sometimes even falling below the bending resistance test standards. This is mainly because the abrasion-resistant material particles are large and have poor compatibility with the main resin of the coating, causing surface cracking during long-term wear and use, thus affecting the lifespan of the shoe upper. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: how to provide a slurry that can make the obtained coating have both excellent wear resistance and bending resistance, and its preparation method and the obtained coating.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a MoS2 slurry, comprising the following raw materials by weight percentage: 11.2-20% nano-sheet MoS2 dispersion, 60-80% aqueous polyurethane resin and additives;

[0006] The nanosheet MoS2 dispersion comprises the following raw materials in weight percentages: 5-15% MoS2 powder, 5-15% dispersant and 70-90% solvent.

[0007] Another technical solution adopted in this invention is: a coating obtained by printing with the above-mentioned MoS2 slurry.

[0008] Another technical solution adopted in this invention is: a method for preparing the above-mentioned MoS2 slurry, comprising the following steps:

[0009] S1: MoS2 powder, dispersant and solvent are mixed and ultrasonically treated to obtain nanosheet MoS2 dispersion;

[0010] S2: Mix and disperse nanosheet MoS2 dispersion, waterborne polyurethane resin and additives, and then grind to obtain MoS2 slurry.

[0011] The beneficial effects of the present invention are as follows: the slurry of the present invention contains nano-sheet MoS2 dispersion, which can achieve the effect of being thinner, lighter, and more elastic, obtaining a softer hand feel, and having excellent wear resistance and bending resistance. Detailed Implementation

[0012] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments.

[0013] A MoS2 slurry comprises the following raw materials by weight percentage: 11.2–20% nano-sheet MoS2 dispersion, 60–80% aqueous polyurethane resin, and additives;

[0014] The nanosheet MoS2 dispersion comprises the following raw materials in weight percentages: 5-15% MoS2 powder, 5-15% dispersant and 70-90% solvent.

[0015] As can be seen from the above description, the beneficial effects of the present invention are as follows: The present invention adds nano-sheet MoS2 dispersion to the slurry. The nano-sheet MoS2 has a layered structure, relatively weak interlayer bonding force, and low shear strength, which plays an excellent role in lubrication and friction reduction. At the same time, it also achieves the effect of being thinner, lighter, and more elastic, resulting in a softer feel, bending resistance, and meeting the physical and mechanical properties required for shoe upper functional materials.

[0016] Adding a dispersant to a nanosheet-like MoS2 dispersion can improve the steric hindrance between the dispersions, prevent MoS2 powder from contacting, and provide good dispersion stability, which helps to form a softer sheet-like wear-resistant layer.

[0017] Furthermore, the solvent includes propylene glycol and water.

[0018] As described above, the nanosheet-like MoS2 of this invention is prepared by using MoS2 powder and a solvent containing propylene glycol. Propylene glycol is used as an exfoliating solvent, and the resulting dispersion can be directly used to mix MoS2 slurry without drying into a solid, effectively improving work efficiency. Conventional exfoliating solvents generally use volatile solvents such as methylpyrrolidine, ethanol, and isopropanol. Adding these directly to the slurry can lead to excessively rapid drying of the coating and poor film quality. This invention uses propylene glycol as an exfoliating solvent. Propylene glycol has a slow evaporation rate, and its direct addition to the slurry helps form a uniform film layer. Its drying speed meets the requirements of coating printing, avoiding both excessively rapid drying and poor film quality, and excessively slow drying, which would affect printing efficiency. Propylene glycol can alter the permeability and wettability of aqueous solutions and also has a dispersing effect, increasing the concentration of added MoS2 powder while preventing its agglomeration.

[0019] Furthermore, the solvent consists of propylene glycol and water in a volume ratio of 6 to 8:3.

[0020] As described above, excessive propylene glycol will lead to excessively fast coating drying and poor film quality; insufficient addition will result in poor peeling performance. Therefore, the solvent should be controlled to consist of propylene glycol and water in a volume ratio of 6–8:3.

[0021] Furthermore, the waterborne polyurethane resin is an aliphatic polyurethane.

[0022] As can be seen from the above description, the use of soft aliphatic polyurethane as the waterborne polyurethane resin results in good film-forming properties and a soft film with excellent wash fastness, good elongation and resilience, and excellent dye compatibility and color development.

[0023] Furthermore, the additives include at least one of leveling agents, defoamers, thickeners, and fumed silica.

[0024] As described above, leveling agents enable the slurry to form a smooth, uniform coating during the drying process, effectively reducing surface tension and improving its leveling and uniformity. Defoamers adjust the product's defoaming properties, preventing air bubbles from forming during stirring and printing, which can lead to printing defects after bursting. Thickeners adjust the viscosity and thixotropy of the slurry, while fumed silica adjusts its rheological and thixotropic properties.

[0025] Furthermore, the dispersant is a nonionic aqueous dispersant.

[0026] As described above, treating two-dimensional nanosheet materials with dispersants containing polar functional groups results in the generation of negative charges on the outer surface of the material, making it unstable. Therefore, this invention selects a nonionic aqueous dispersant.

[0027] Further, it is composed of the following raw materials in weight percentage: 11.2-20% nano-sheet MoS2 dispersion, 60-80% waterborne polyurethane resin, 0.2-1% leveling agent, 0.2-1.8% defoamer, 1-3% thickener, 1-3% fumed silica, and the balance being water.

[0028] As can be seen from the above description, excessive leveling agent content leads to a sharp decrease in the surface tension of the slurry, making the slurry prone to bubbling and causing printing defects. Insufficient leveling agent content leads to a decrease in the smoothness and uniformity of the coating during the drying and film formation process, resulting in printing quality defects.

[0029] Another technical solution adopted in this invention is: a coating obtained by printing with the above-mentioned MoS2 slurry.

[0030] As can be seen from the above description, coatings can be prepared precisely and flexibly by changing the printing pattern, avoiding waste of edges and corners and environmental pollution caused by cutting.

[0031] Another technical solution adopted in this invention is: a method for preparing the above-mentioned MoS2 slurry, comprising the following steps:

[0032] S1: MoS2 powder, dispersant and solvent are mixed and ultrasonically treated to obtain nanosheet MoS2 dispersion;

[0033] S2: Mix and disperse nanosheet MoS2 dispersion, waterborne polyurethane resin and additives, and then grind to obtain MoS2 slurry.

[0034] As described above, existing technologies typically use template methods or high-temperature calcination methods to prepare nanosheet-like MoS2, which are complex and energy-intensive. This invention utilizes ultrasonic liquid-phase exfoliation of MoS2 mineral powder, a simple and easy-to-operate process. During liquid-phase exfoliation, propanol is used as an exfoliating agent, and propylene glycol, as a low-molecular-weight alcohol, can alter the permeability and wettability of the aqueous solution, improving the efficiency of solution penetration into the MoS2 powder and thus enhancing the exfoliation efficiency.

[0035] Furthermore, during the ultrasonic treatment of S1, the temperature is 0–30°C.

[0036] As can be seen from the above description, excessively high temperatures during ultrasonic treatment can cause water and propylene glycol to evaporate too quickly, affecting the dispersion effect.

[0037] For further reduction, during ultrasonic treatment of S1, ultrasonic treatment is performed at a power of 250-350W for 4-6 hours.

[0038] Furthermore, the viscosity of the MoS2 slurry is 10,000–40,000 cps.

[0039] The materials used in the following embodiments include:

[0040] Waterborne polyurethane resin: Weng Kai'er S-335; Leveling agent: Tego-270; Defoamer: Tego Foamex 810; Thickener: BASF low-shear polyurethane thickener PU 1193; Fumed silica: Wacker HDK-N20 hydrophilic silica with a specific surface area of ​​200; MoS2 powder, purity ≥98.5%, average particle size D50, 3.0~6.0um; Nonionic aqueous dispersant: BYK-192 aqueous dispersant from BYK Chemicals, Germany; Isocyanate curing agent: Wanhua 161.

[0041] The equipment used in the following examples includes: a PTR65 three-roll mill from Guangdong Pailer Intelligent Nanotechnology Co., Ltd., with grinding parameters of 0.75KW 50Hz; and a viscometer with a 100# rotor from Shanghai Changji Geological Instrument Co., Ltd.

[0042] Embodiment 1 of the present invention is: a MoS2 slurry, the raw materials of which, by weight percentage, are: 20% nano-sheet MoS2 dispersion, 74.5% aqueous polyurethane resin, 0.5% leveling agent, 1.0% defoamer, 2.0% thickener and 2.0% fumed silica; the viscosity of the MoS2 slurry is 21000 cps.

[0043] The raw materials for the nanosheet MoS2 dispersion, by weight percentage, are: 10% MoS2 powder, 10% nonionic aqueous dispersant, 56% propylene glycol and 24% water.

[0044] Embodiment 2 of the present invention is: the preparation method of the MoS2 slurry in Embodiment 1, comprising the following steps:

[0045] S1: Mix MoS2 powder, dispersant and solvent according to the ratio and stir for 10 hours. Then, sonicate the resulting solution in a Deyisheng ultrasonic cleaner 040S at a power of 300W for 5 hours to obtain a uniformly dispersed nano-sheet MoS2 dispersion. During the sonication process, the temperature of the ultrasonic water bath is controlled below 30℃ by adding ice cubes at regular intervals.

[0046] S2: Mix and disperse the nano-sheet MoS2 dispersion, waterborne polyurethane resin, leveling agent, defoamer, thickener and fumed silica according to the specified ratio, and then grind twice using a three-roll mill PTR65 (Guangdong Pailer Intelligent Nanotechnology Co., Ltd.) until the fineness is 0-10μm to obtain MoS2 slurry.

[0047] Embodiment 3 of the present invention involves printing a coating using the aforementioned MoS2 paste. The printing method is as follows:

[0048] Step 1: Add isocyanate curing agent to the MoS2 slurry of Example 1. The mass of isocyanate curing agent is 5% of the mass of MoS2 slurry.

[0049] Step 2: Clean the printing table thoroughly and apply two coats of adhesive using a special adhesive board; ensure the table is clean and that there is no residual adhesive at the printing areas.

[0050] Step 3: Fix the mesh fabric onto the printing table with the marked position lines;

[0051] Step 4: Print the paste onto the mesh multiple times until the paste thickness is 0.5mm. After each printing, dry it at 70℃ until the surface is dry (not sticky to the touch) before printing the next layer. Continue printing until the printing is complete, and then let it air dry at room temperature for 24 hours.

[0052] Embodiment four of the present invention is as follows:

[0053] The only difference between Example 4 and Example 3 is that, by weight percentage, the raw materials for the nanosheet MoS2 dispersion are: 5% MoS2 powder, 15% nonionic aqueous dispersant, 56% propylene glycol and 24% water; the viscosity of the MoS2 slurry is 20000 cps.

[0054] Embodiment five of the present invention is as follows:

[0055] The difference between Example 5 and Example 3 is only that: the MoS2 slurry, by weight percentage, consists of: 20% nano-sheet MoS2 dispersion, 60% aqueous polyurethane resin, 0.2% leveling agent, 0.2% defoamer, 1% thickener, 1% fumed silica, and 17.6% water; the viscosity of the MoS2 slurry is 10000 cps.

[0056] The raw materials for the nanosheet MoS2 dispersion, by weight percentage, are: 5% MoS2 powder, 5% nonionic aqueous dispersant, 62% propylene glycol and 28% water;

[0057] When preparing MoS2 slurry, grind it to a fineness of 1 μm.

[0058] Embodiment six of the present invention is as follows:

[0059] The difference between Example 6 and Example 3 is only that: the MoS2 slurry, by weight percentage, consists of: 11.20% nano-sheet MoS2 dispersion, 80% waterborne polyurethane resin, 1% leveling agent, 1.8% defoamer, 3% thickener and 3% fumed silica; the viscosity of the MoS2 slurry is 40000 cps.

[0060] The raw materials for the nanosheet MoS2 dispersion, by weight percentage, are: 15% MoS2 powder, 15% nonionic aqueous dispersant, 50% propylene glycol and 20% water;

[0061] When preparing MoS2 slurry, grind it to a fineness of 5μm.

[0062] Embodiment seven of the present invention is as follows:

[0063] The difference between Example 7 and Example 3 is only that: the MoS2 slurry, by weight percentage, consists of: 20% nano-sheet MoS2 dispersion, 70% aqueous polyurethane resin, 0.6% leveling agent, 1% defoamer, 2% thickener, 2% fumed silica, and 4.4% water; the viscosity of the MoS2 slurry is 23000 cps.

[0064] Comparative Example 1 of the present invention is:

[0065] The only difference between Comparative Example 1 and Example 3 is:

[0066] The raw materials for the nanosheet MoS2 dispersion, by weight percentage, are: 3% MoS2 powder, 17% nonionic aqueous dispersant, 56% propylene glycol and 24% water; the viscosity of the MoS2 slurry is 17000 cps.

[0067] Comparative Example 2 of the present invention is as follows:

[0068] The only difference between Comparative Example 2 and Example 3 is:

[0069] The raw materials for the nanosheet MoS2 dispersion, by weight percentage, are: 18% MoS2 powder, 7% nonionic aqueous dispersant, 52.5% propylene glycol and 22.5% water; the viscosity of the MoS2 slurry is 23000 cps; the MoS2 slurry is prepared by grinding to a fineness of 6 μm.

[0070] Comparative Example 3 of the present invention is as follows:

[0071] The only difference between Comparative Example 3 and Example 3 is:

[0072] The raw materials for the nanosheet MoS2 dispersion, by weight percentage, are: 20% MoS2 powder, 5% nonionic aqueous dispersant, 52.5% propylene glycol and 22.5% water; the viscosity of the MoS2 slurry is 25000 cps; the MoS2 slurry is prepared by grinding to a fineness of 10 μm.

[0073] Comparative Example 4 of the present invention is as follows:

[0074] The only difference between Comparative Example 4 and Example 3 is that the nanosheet MoS2 dispersion in the slurry was replaced with an equal mass of water.

[0075] Comparative Example 5 of the present invention is:

[0076] The only difference between Comparative Example 5 and Example 3 is that the propylene glycol in the slurry is replaced with an equal mass of ethanol.

[0077] The coatings obtained from Examples 3-7 and Comparative Examples 1-3 were subjected to high temperature and high humidity resistance, flexural resistance, and abrasion resistance tests. The test results are shown in Table 1. The high temperature and high humidity resistance test was conducted according to the method specified in GB / T3903.7-2019; the flexural resistance test was conducted according to the method specified in ISO17694:2016; and the abrasion resistance test was conducted according to the method specified in QB / T 4545-2013.

[0078] Table 1

[0079]

[0080] Observing Table 1 and comparing the data of Examples 3 and 4 with Comparative Examples 1 to 3, it can be seen that the flexural resistance and abrasion resistance of the coating are related to the amount of MoS2 powder and the amount of water-based dispersant added. Comparing the data of Example 3 and Comparative Example 4, it can be seen that adding nano-sheet MoS2 dispersion can effectively improve the abrasion resistance of the coating while maintaining flexural resistance. Comparing Example 3 and Comparative Example 5, it can be seen that using a volatile reagent as a stripping agent will reduce the flexural resistance and abrasion resistance of the coating.

[0081] In summary, the MoS2 slurry, coating, and preparation method provided by this invention have the following advantages:

[0082] 1. Adding nano-sheet MoS2 dispersion to the slurry can result in a thinner, lighter, and more elastic material with a softer feel, while also providing excellent wear resistance and bending resistance.

[0083] 2. The process of ultrasonic liquid phase stripping of MoS2 mineral powder is simple and easy to operate.

[0084] 3. This invention uses propylene glycol as a stripping solvent, which can change the permeability and wettability of the aqueous solution, improve the efficiency of the solution immersing in MoS2 powder, and improve the stripping efficiency. Propylene glycol has a slow evaporation rate and can be directly added to the slurry, which helps to form a uniform film layer. Its drying speed meets the requirements of coating printing and will not cause the film to dry too quickly, resulting in poor film quality. Propylene glycol also has a dispersing effect, which can increase the concentration of added MoS2 powder while keeping the MoS2 powder from agglomerating.

[0085] 4. Adding a dispersant to the nano-sheet MoS2 dispersion can improve the steric hindrance between the dispersions, prevent the MoS2 powder from contacting, and provide good dispersion stability, which helps to form a softer sheet-like wear-resistant layer.

[0086] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made using the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A MoS2 slurry, characterized in that, It is composed of the following raw materials by weight percentage: 11.2~20% nano-sheet MoS2 dispersion, 60~80% waterborne polyurethane resin and additives; the addition of nano-sheet MoS2 dispersion can effectively improve the wear resistance of the coating while maintaining the bending resistance. The nanosheet MoS2 dispersion is composed of the following raw materials by weight percentage: 5-15% MoS2 powder, 5-15% dispersant and 70-90% solvent, wherein the solvent is composed of propylene glycol and water in a volume ratio of 6-8:3; the dispersant is a nonionic aqueous dispersant.

2. The MoS2 slurry according to claim 1, characterized in that, The additives include at least one of leveling agents, defoamers, thickeners, and fumed silica.

3. The MoS2 slurry according to claim 1, characterized in that, It is composed of the following raw materials by weight percentage: 11.2~20% nano-sheet MoS2 dispersion, 60~80% waterborne polyurethane resin, 0.2~1% leveling agent, 0.2~1.8% defoamer, 1~3% thickener, 1~3% fumed silica, and the balance being water.

4. The coating obtained by printing with the MoS2 paste according to any one of claims 1-3.

5. The method for preparing MoS2 slurry according to any one of claims 1-3, characterized in that, Includes the following steps: S1: MoS2 powder, dispersant and solvent are mixed and ultrasonically treated to obtain nanosheet MoS2 dispersion; S2: Mix and disperse nanosheet MoS2 dispersion, waterborne polyurethane resin and additives, and then grind to obtain MoS2 slurry.

6. The method for preparing MoS2 slurry according to claim 5, characterized in that, During the ultrasonic treatment of S1, the temperature is 0~30℃.

7. The method for preparing MoS2 slurry according to claim 5, characterized in that, The viscosity of the MoS2 slurry is 20,000~23,000 cps.

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