An anti-icing coating composition and method of making the same

Abstract

The present application belongs to the technical field of coating, and particularly relates to an anti-icing coating composition and a preparation method thereof.The anti-icing coating composition comprises the following components: component A: 50.0-70.0% of fluorocarbon resin, 0.5-1.0% of defoaming agent, 0.5-1.0% of dispersing agent, 3.0-14.0% of dimethylbenzene, 10.0-20.0% of titanium white powder, 10.0-20.0% of microcapsule particles and 0.1-0.3% of leveling agent according to percentage by weight; component B: 70.0-90.0% of isocyanate curing agent and 10-30% of dimethylbenzene according to percentage by weight; and the mass ratio of component A to component B is 100:15.The present application realizes high-efficiency anti-icing / de-icing effect through the synergistic effect of low-surface-energy fluorocarbon resin and microcapsules, the contact angle of the coating can reach more than 110°, and the coating still has good anti-icing ability after being damaged by 120-mesh sandpaper polishing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coating, and particularly relates to an anti-icing coating composition and a preparation method thereof. BACKGROUND

[0002] Coal adhesion phenomenon has been an important problem for coal enterprises in the process of production, transportation and storage. Coal adhesion is divided into wet adhesion and frozen adhesion. Wet adhesion refers to an interfacial adhesion phenomenon of coal with a certain water content on the surface of storage and transportation equipment such as mine cars, which is relatively easy to clean. Frozen adhesion refers to the adhesion of coal to the surface of transportation or storage equipment due to the freezing of water in coal at low temperature, including the freezing of internal water and the freezing of water between coal and coal car wall. For coal storage and transportation, frozen adhesion is more harmful than wet adhesion, which generally occurs on the basis of wet adhesion. When the temperature is below zero, low-temperature adhesion phenomenon occurs between the frozen coal and the surface of coal storage and transportation equipment.

[0003] Under cold weather conditions, especially in an environment with an average outdoor temperature of -30 to -15°C, the coal adhesion rate of mine cars and other coal transportation vehicles is as high as 30% to 60%, which needs to be cleaned regularly by humans, which not only affects work efficiency, but also may cause damage to the carriages. In some thermal power plants and coal preparation plants, due to different coal qualities and certain water content, the adhesion of coal to the coal storage silo leads to the blockage of the coal storage silo, causing huge economic losses. At present, the problem of coal adhesion has seriously restricted the production and efficiency of coal enterprises, and it is urgent to solve the problem of frozen adhesion of coal storage and transportation equipment.

[0004] At present, the main method for coal mines to prevent and solve the problem of frozen coal adhesion during coal transportation is to spray antifreeze (such as calcium chloride and ethylene glycol solution) to prevent coal freezing. However, this approach has many drawbacks: on the one hand, it needs to be sprayed before each coal loading, and the continuous effect time is short, and the repeated use rate is low; on the other hand, the antifreeze needs to directly contact the train carriage, which not only causes corrosion damage to the equipment, but also causes serious environmental pollution. For the coal carriages that have frozen, most coal mines still use manual cleaning to solve the problem of coal adhesion of mine cars, which is time-consuming and laborious, and has low efficiency.

[0005] For coal transportation in cold regions, designing and preparing surface materials with anti-icing / anti-de-icing properties by modifying the surface properties of materials can reduce coal adhesion to the bottom and sides of the wagon in winter, reduce manual cleaning, or decrease the use of antifreeze, thereby improving the efficiency of coal transportation. Superhydrophobic materials, due to their low surface energy, can reduce the contact area with droplets, thus slowing down the freezing rate to some extent, but they cannot completely prevent ice and snow from forming, especially when the coal has a high moisture content; the coal will still freeze and adhere to the bottom of the wagon. Superhydrophobic materials typically provide good protection initially, but as coal dust wears down the material surface, the superhydrophobic structure is damaged, and the protective effect significantly decreases.

[0006] Chinese patent CN 109111849 A discloses an anti-icing coating and its preparation method. This involves mixing silicone rubber, a fluorinated monomer, a binder, and a catalyst, causing a cross-linking reaction to introduce fluorinated side chains into the silicone rubber, forming a fluorinated polysiloxane. Liquid paraffin is then added, and the mixture is heated to prepare an organosilicon gel, which is finally cured to obtain an anti-icing coating with low ice adhesion strength. However, this coating exhibits poor abrasion resistance; after scratches, the bonding strength between ice and the material increases. Simultaneously, the lubricating layer formed by the liquid paraffin loses its lubricating effect as the coating wears down. Chinese patent CN113004750 A provides an antibacterial anti-icing coating and its preparation method. This method introduces organosilicon-modified paraffin and dual-terminated vinyl silicone oil into a fluorosilicone resin, utilizing the stress difference between the coating's flexibility at low temperatures and the ice layer to reduce ice adhesion strength. However, this method also suffers from poor abrasion resistance, easy loss of the lubricating layer due to wear, and poor long-term effectiveness. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide an anti-icing coating composition and its preparation method.

[0008] To achieve the above objectives, the technical solution adopted is:

[0009] One object of the present invention is to provide an anti-icing coating composition comprising the following components:

[0010] Component A: By weight percentage, it includes 50.0-70.0% fluorocarbon resin, 0.5-1.0% defoamer, 0.5-1.0% dispersant, 3.0-14.0% xylene, 10.0-20.0% titanium dioxide, 10.0-20.0% microcapsule particles, and 0.1-0.3% leveling agent;

[0011] Component B: By weight percentage, it includes 70.0-90.0% isocyanate curing agent and 10-30% xylene;

[0012] The mass ratio of component A to component B is 100:15.

[0013] Preferably, the wall thickness of the microcapsule particles is 20-80 nm.

[0014] Preferably, the particle size of the microcapsule particles is 350-550 nm.

[0015] More preferably, the wall thickness of the microcapsule particles is 50 nm, and the particle size of the microcapsule particles is 400-500 nm.

[0016] Preferably, the method for preparing the microcapsule particles includes the following steps:

[0017] Step 1: Emulsion Preparation

[0018] ① Aqueous phase preparation: Dissolve sodium dodecyl sulfate in deionized water and add ammonium persulfate. Stir at 25°C until the solution becomes clear; ② Oil phase preparation: Mix long-chain alkane fatty acids, methyl methacrylate and styrene evenly; ③ Pre-emulsification: Slowly add the oil phase to the aqueous phase, shear to form a crude emulsion, homogenize the crude emulsion to obtain the emulsion;

[0019] Step 2: Polymerization reaction

[0020] 100 grams of emulsion were reacted under nitrogen protection at 70-80°C for 2-6 hours. The emulsion changed from a translucent state to a milky white gel. Hydroquinone was added, and then the mixture was rapidly cooled to 25°C.

[0021] Step 3: Purification and drying of microcapsules

[0022] Ethanol was added to the emulsion generated in step 2, followed by centrifugation to remove the supernatant. The mixture was then filtered and washed to ensure that the pH of the filtrate was neutral. The powder obtained by filtration was then frozen. Subsequently, the mixture was heated under vacuum to perform sublimation drying. The temperature was then raised again and maintained to obtain microcapsule particles with a wall thickness of 20-80 nm and a particle size range of 350-550 nm.

[0023] More preferably, the method for preparing the microcapsule particles includes the following specific steps:

[0024] Step 1: Emulsion Preparation

[0025] ① Aqueous phase preparation: In a beaker, dissolve 2.4 g of SDS (sodium dodecyl sulfate) in 76 g of deionized water and add 0.8 g of APS (ammonium persulfate). Stir at 500 rpm for 30 minutes at 25°C until the solution becomes clear. ② Oil phase preparation: Mix 12 g of long-chain alkane fatty acid, 20 g of MMA (methyl methacrylate), and 8 g of St (styrene) according to the mass ratio, and mix in a vortex mixer for 1 minute. ③ Pre-emulsification: Slowly add the oil phase to the aqueous phase and shear at 15,000 rpm for 5 minutes using a high-speed shear mill to form a crude emulsion. Then, place the crude emulsion in a high-pressure homogenizer and homogenize it three times at a pressure of 40 MPa to obtain an emulsion with a particle size in the range of 300-400 nanometers.

[0026] Step 2: Polymerization reaction

[0027] Transfer 100g of emulsion to a three-necked flask and purge with nitrogen for protection. React at 75°C for 2-6 hours. The emulsion will change from a translucent state to a milky white gel. Finally, add 0.1g of hydroquinone (dissolved in 1ml of ethanol) and then rapidly cool to 25°C.

[0028] Step 3: Purification and drying of microcapsules

[0029] 20 mL of ethanol was added to the emulsion generated in the reaction, and then the mixture was centrifuged at 8000 rpm for 10 minutes to remove the supernatant. Next, vacuum filtration was performed, followed by washing three times alternately with deionized water and anhydrous ethanol to ensure the pH of the filtrate was neutral. The obtained powder was then frozen at -30°C for 12 hours. Afterward, under a vacuum of 0.1 bar, the temperature was gradually increased from -30°C to -10°C at a rate of 2°C per hour and maintained at this temperature for sublimation drying for 12 hours. Subsequently, the temperature was increased to 25°C at a rate of 5°C per hour and maintained for 6 hours. Finally, microcapsule particles with a wall thickness of 20-80 nm and a particle size range of 350-550 nm were obtained.

[0030] Preferably, the fluorocarbon resin has a hydroxyl value of 108-122 mgKOH / g and a solid content of 54-58 wt%.

[0031] Preferably, the isocyanate curing agent has an NCO group content of 23.1-23.5 wt% and a solid content of 100 wt%.

[0032] The second objective of this invention is to provide a method for preparing the anti-icing coating composition, comprising the following steps: dispersing and mixing fluorocarbon resin, titanium dioxide, microcapsule particles, defoamer, dispersant, leveling agent, and xylene uniformly to obtain component A with a fineness ≤30 micrometers; mixing isocyanate curing agent and xylene uniformly to obtain component B; and mixing component A and component B to obtain the anti-icing coating composition.

[0033] More preferably, the preparation method of the anti-icing coating composition includes the following specific steps: first, add fluorocarbon resin and xylene solvent into a mixing tank, start stirring and set the speed to 500 r / min, add defoamer, dispersant, titanium dioxide and microcapsule particles in sequence according to the ratio under stirring conditions, disperse at 1500 r / min for 0.5 h after addition, reduce the speed to 800 r / min and add leveling agent, disperse for 10 min, and finally filter the material with a 120 mesh filter screen to discharge the material. The fineness of the fluorocarbon coating is ≤30 μm.

[0034] Component B: First, add the isocyanate curing agent and xylene to the mixing tank, start the stirring speed at 500 r / min, disperse for 20 min, and finally filter the material through a 120 mesh filter.

[0035] Weigh components A and B into the mixing tank at a mass ratio of 100:15, start stirring at 300r / min for 3-5 minutes, let stand for 10 minutes, and then apply the coating.

[0036] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention uses fluorocarbon resin as the film-forming material, which has excellent wear resistance. The resulting coating can protect the substrate for a long time, thereby improving the service life of transportation equipment. Utilizing the synergistic effect of fluorocarbon resin and microcapsules, efficient anti-icing and de-icing functions are achieved. When the coating is scratched or damaged, the microcapsule shell is destroyed, releasing the long-chain fatty acids inside, forming a self-lubricating layer on the coating surface, reducing the adhesion strength to ice. The microcapsule particles are evenly distributed throughout the coating system and do not all migrate to the coating surface. As the coating wears down, they are slowly released over a long period, continuously forming a lubricating layer. The lubrication effect is not weakened due to coating wear, thus achieving a long-lasting anti-icing effect. The contact angle of the coating can reach over 110°, and even after being damaged by 120-grit sandpaper, the coating still has good anti-icing capabilities. Detailed Implementation

[0037] The present invention will be described below with reference to examples. These examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0038] The raw materials used in the following examples are:

[0039] ① The fluorocarbon resin is Daikin ZU-201 fluorocarbon resin from Japan, with a hydroxyl value of 108-122 mgKOH / g.

[0040] Solid content is 54-58 wt%.

[0041] ②The isocyanate curing agent is Asahi Kasei TPA100, with an NCO content of 23.1-23.5 wt% and a solid content of 100 wt%.

[0042] ③ The titanium dioxide is of the R2 rutile type, model R996, TiO2 2≥ 95%, volatile matter content ≤0.5%, average particle size ≤10μm.

[0043] ⑤ The defoamer is at least one of AFCONA 2045, BYK070, and Tech-430;

[0044] ⑥ The dispersant is at least one of AFCONA5010, AFCONA5065, and TEGO 685;

[0045] ⑦ The leveling agent is at least one of AFCONA3593, BYK333, and Tech-2409;

[0046] ⑧ Xylene: Purity ≥ 99.5%, moisture content ≤ 0.03%.

[0047] ⑨ Long-chain alkane fatty acids: Palmitoleic acid with a melting point of 0-1.0℃; Manufacturer: Sime Darby, Malaysia.

[0048] ⑩ Methyl methacrylate: Purity ≥ 99%, Manufacturer: Sigma-Aldrich.

[0049] ⑪ Styrene: Purity ≥ 99%, Manufacturer: Alfa Aesar.

[0050] ⑫ Ammonium persulfate: purity ≥98%, analytical grade; manufacturer: Sinopharm Group.

[0051] ⑬ Sodium dodecyl sulfate (SDS): Purity ≥99%, biological grade; manufacturer: TCI Chemicals.

[0052] Example of microcapsule particle preparation

[0053] Step 1: Emulsion Preparation

[0054] ① Aqueous phase preparation: In a beaker, dissolve 2.4 g of SDS (sodium dodecyl sulfate) in 76 g of deionized water and add 0.8 g of APS (ammonium persulfate). Stir at 500 rpm for 30 minutes at 25°C until the solution becomes clear. ② Oil phase preparation: Mix 12 g of long-chain alkane fatty acid, 20 g of MMA (methyl methacrylate), and 8 g of St (styrene), and mix in a vortex mixer for 1 minute. ③ Pre-emulsification: Slowly add the oil phase to the aqueous phase and shear at 15,000 rpm for 5 minutes using a high-speed shear mill to form a crude emulsion. Then, homogenize the crude emulsion three times in a high-pressure homogenizer at 40 MPa to obtain an emulsion with a particle size in the range of 300-400 nanometers.

[0055] Step 2: Polymerization reaction

[0056] Transfer 100g of the emulsion to a three-necked flask and purge with nitrogen for protection. React at 75°C for 4 hours, during which the emulsion will change from a translucent state to a milky white gel. Finally, add 0.1g of hydroquinone (dissolved in 1ml of ethanol) and then rapidly cool to 25°C.

[0057] Step 3: Purification and drying of microcapsules

[0058] 20 mL of ethanol was added to the emulsion generated in the reaction, and then the mixture was centrifuged at 8000 rpm for 10 minutes to remove the supernatant. Next, vacuum filtration was performed, and the mixture was washed three times alternately with deionized water and anhydrous ethanol to ensure the pH of the filtrate was neutral. The obtained powder was frozen at -30°C for 12 hours; then, under a vacuum of 0.1 bar, the temperature was gradually increased from -30°C to -10°C at a rate of 2°C per hour and maintained at this temperature for sublimation drying for 12 hours. Subsequently, the temperature was increased to 25°C at a rate of 5°C per hour and maintained for 6 hours. Through this series of steps, microcapsule particles WJ-50 with a wall thickness of 50 nm and a particle size range of 400-500 nm were finally obtained.

[0059] By changing the polymerization time in step 2, microcapsule particles with different wall thicknesses and particle sizes were prepared. When the reaction time was changed to 2 hours, microcapsule particles WJ-20 with a wall thickness of 20 nanometers and a particle size range of 350-450 nanometers were prepared. When the reaction time was changed to 6 hours, microcapsule particles WJ-80 with a wall thickness of 80 nanometers and a particle size range of 450-550 nanometers were prepared.

[0060] The preparation method of the anti-icing coating is as follows: First, add fluorocarbon resin and xylene solvent into the mixing tank, start the stirrer and set the speed to 500 r / min. Under stirring conditions, add defoamer, dispersant, titanium dioxide and microcapsule particles in sequence according to the ratio. After the addition is completed, disperse at 1500 r / min for 0.5 h. Then reduce the speed to 800 r / min and add leveling agent. Disperse for 10 min. Finally, filter the material through a 120 mesh filter. The fineness of the fluorocarbon coating is ≤30 μm.

[0061] Component B: First, add the isocyanate curing agent and xylene to the mixing tank, start the stirring speed at 500 r / min, disperse for 20 min, and finally filter the material through a 120 mesh filter.

[0062] Weigh components A and B into the mixing tank at a mass ratio of 100:15, start stirring at 300r / min for 3-5 minutes, let stand for 10 minutes, and then apply the coating.

[0063] Example 1

[0064] The weight percentage of each component in the coating is as follows:

[0065] Component A: 60% fluorocarbon resin, 15% titanium dioxide, 10% WJ-50 microcapsule particles, 0.7% defoamer AFCONA 2045, 0.6% dispersant AFCONA5010, 0.2% leveling agent AFCONA3593, and 13.5% xylene.

[0066] Component B: 84% isocyanate curing agent, 16% xylene.

[0067] Example 2

[0068] Component A: 60% fluorocarbon resin, 15% titanium dioxide, 15% WJ-50 microcapsule particles, 0.7% defoamer BYK070, 0.6% dispersant AFCONA5065, 0.2% leveling agent BYK333, and 8.5% xylene.

[0069] Component B: 84% isocyanate curing agent, 16% xylene.

[0070] Example 3

[0071] Component A: 60% fluorocarbon resin, 15% titanium dioxide, 20% WJ-50 microcapsule particles, 0.7% defoamer Tech-430, 0.6% dispersant TEGO 685, 0.2% leveling agent Tech-2409, and 3.5% xylene.

[0072] Component B: 84% isocyanate curing agent, 16% xylene.

[0073] Comparative Example 1

[0074] The weight percentage of each component in the coating is as follows:

[0075] Component A: 60% fluorocarbon resin, 30% titanium dioxide, 0.7% defoamer BYK070, 0.6% dispersant AFCONA5065, 0.2% leveling agent BYK333, and 8.5% xylene.

[0076] Component B: 84% isocyanate curing agent, 16% xylene.

[0077] Comparative Example 2

[0078] Component A: 60% fluorocarbon resin, 15% titanium dioxide, 15% WJ-20 microcapsule particles, 0.7% defoamer BYK070, 0.6% dispersant AFCONA5065, 0.2% leveling agent BYK333, and 8.5% xylene.

[0079] Component B: 84% isocyanate curing agent, 16% xylene.

[0080] Comparative Example 3

[0081] Component A: 60% fluorocarbon resin, 15% titanium dioxide, 15% WJ-80 microcapsule particles, 0.7% defoamer BYK070, 0.6% dispersant AFCONA5065, 0.2% leveling agent BYK333, and 8.5% xylene.

[0082] Component B: 84% isocyanate curing agent, 16% xylene.

[0083] Test method:

[0084] 1. Contact Angle Test: Using a contact angle meter, the contact angle between a water droplet and different materials is measured to determine the hydrophobicity of different materials.

[0085] 2. Abrasion Resistance Test: The abrasion resistance of different materials was determined according to the national standard GB / T 1768-2006. The test grinding wheel was CS-10, with a load of 500g and a rotation speed of 1000r.

[0086] 3. Ice Adhesion Strength: At a temperature of -20±1℃, cylindrical ice columns with a diameter of 1cm and a height of 1cm were frozen on different material surfaces. A digital push-pull force gauge was used to determine the minimum force required for the ice column to slide on the material surface.

[0087] 4. Adhesion strength after icing following 120-grit sanding: The coating was sanded with 5 kg of force using 120-grit sandpaper, repeating 10 times. Then, cylindrical icicles with a diameter of 1 cm and a height of 1 cm were frozen onto the sanded material surface. A digital push-pull force gauge was used to determine the minimum force required for the icicle to slide on the material surface.

[0088] The test results are shown in Table 1.

[0089] Table 1. Test results of anti-icing coatings in Examples 1-3 and Comparative Examples 1-3

[0090]

[0091] Based on the test results above, it can be seen that the coating with added WJ-50 microcapsules exhibits good wear resistance and maintains good anti-icing performance even after external damage. Comparative Examples 1 to 3 show that when the microcapsule wall thickness is too large, the microcapsule structure is difficult to break under external force, preventing the release of internal long-chain alkane fatty acids and the formation of an effective lubricating layer. Therefore, the improvement in anti-icing effect is not significant. Conversely, when the microcapsule wall thickness is too thin, the microcapsule structure is easily destroyed under external force, significantly improving anti-icing ability. However, this also leads to increased coating wear, resulting in a significantly shorter service life for the same thickness.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An anti-icing coating composition, characterized in that, It includes the following components: Component A: by weight percentage, it includes 50.0-70.0% fluorocarbon resin, 0.5-1.0% defoamer, 0.5-1.0% dispersant, 3.0-14.0% xylene, 10.0-20.0% titanium dioxide, 10.0-20.0% microcapsule particles, and 0.1-0.3% leveling agent; Component B: By weight percentage, it includes 70.0-90.0% isocyanate curing agent and 10-30% xylene; The mass ratio of component A to component B is 100:15; The wall thickness of the microcapsule particles is 50 nm, and the particle size of the microcapsule particles is 400-500 nm. The method for preparing the microcapsule particles includes the following steps: Step 1: Emulsion Preparation ① Aqueous phase preparation: Dissolve sodium dodecyl sulfate in deionized water and add ammonium persulfate. Stir at 25°C until the solution becomes clear; ② Oil phase preparation: Mix long-chain alkane fatty acids, methyl methacrylate and styrene evenly; ③ Pre-emulsification: Slowly add the oil phase to the aqueous phase, shear to form a crude emulsion, homogenize the crude emulsion to obtain the emulsion; Step 2: Polymerization reaction 100 grams of emulsion were reacted under nitrogen protection at 70-80°C for 2-6 hours. The emulsion changed from a translucent state to a milky white gel. Hydroquinone was added, and then the mixture was rapidly cooled to 25°C. Step 3: Purification and drying of microcapsules Ethanol was added to the emulsion generated in step 2, followed by centrifugation to remove the supernatant. The mixture was then filtered and washed to ensure that the pH of the filtrate was neutral. The powder obtained by filtration was then frozen. Subsequently, the mixture was heated under vacuum to perform sublimation drying. The temperature was raised again and held to obtain microcapsule particles with a wall thickness of 20-80 nm and a particle size range of 350-550 nm. The fluorocarbon resin has a hydroxyl value of 108-122 mgKOH / g and a solid content of 54-58 wt%. The isocyanate curing agent has an NCO group content of 23.1-23.5 wt% and a solid content of 100 wt%.

2. A method for preparing the anti-icing coating composition according to claim 1, characterized in that, The process includes the following steps: dispersing and mixing fluorocarbon resin, titanium dioxide, microcapsule particles, defoamer, dispersant, leveling agent, and xylene until uniform with a fineness ≤30 micrometers to obtain component A; mixing isocyanate curing agent and xylene until uniform to obtain component B; and mixing component A and component B to obtain the anti-icing coating composition.

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