Crack-sensitive high-efficiency deicing coating and preparation method thereof

Abstract

The present application belongs to the field of anti-icing functional materials, and relates to a crack-sensitive high-efficiency de-icing coating and a preparation method thereof. The coating can be constructed by spraying emulsion coating in one step, and a thickness of only 50 microns can realize efficient de-icing based on the crack-sensitive effect. The present application realizes one-step construction of an elastic modulus heterogenization anti-icing coating by using in-situ crosslinking at the emulsion interface. This crosslinking path makes the liquid drops in the emulsion become hard particles with uniform particle size (5-20 microns) and random distribution in the flexible coating. The high-efficiency de-icing coating prepared by the present application has a crack-sensitive effect, exhibits excellent static and dynamic passive de-icing performance, can realize self-weight shedding of large-area ice layer, and realizes efficient ice removal on rotating blades (such as unmanned aerial vehicle rotors and wind turbines).

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of anti-icing functional materials, and relates to a crack-sensitive high-efficiency deicing coating and a preparation method thereof. BACKGROUND

[0002] Ice disaster often causes systematic paralysis in the transportation and energy industries, bringing about safety hazards and economic losses. In order to achieve energy-saving and environmentally-friendly anti- / deicing, the development of passive anti-icing coatings has become a research hotspot in recent years. Due to the complexity of the natural environment, surface icing is often difficult to avoid. Therefore, it is crucial to design an anti-icing surface with stable and efficient deicing ability in practical applications.

[0003] Recently, anti-icing surfaces with crack-promoting ability have shown great potential for efficient deicing. Such anti-icing surfaces usually use flexible polymers as the film-forming matrix, and construct modulus-heterogeneous surfaces by introducing cavity structures (Soft Matter. 2018, 14: 4846-4851), softer gel phases (Mater. Horiz. 2019, 6: 758-766), or doping harder particles (CN115851118), fibers (CN116493217), etc. This causes local stress concentration at the ice-substrate adhesion interface under stress, and the flexible matrix undergoes buckling deformation to generate air pockets (i.e., interface cracks), thereby greatly reducing the ice adhesion strength. However, these surfaces are difficult to promote the efficient propagation of interface cracks - the viscoelasticity of flexible polymer molecular chains often causes the interface air pocket to slip under shear force, which limits the deicing efficiency. An improved solution is to deposit a hard film on the flexible matrix to form a natural micro-crease structure (Natl. Sci. Rev. 2025, 12:nwaf005), where the flexible matrix is responsible for generating buckling deformation, and the hard crease structure initiates interface cracks and promotes interface brittle fracture, i.e., accelerates the propagation of interface cracks.

[0004] However, the above modulus-heterogeneous anti-icing surfaces rely on the elastic deformation of the flexible matrix to generate cracks, and usually require a thickness of several hundred microns or even millimeters to ensure a relatively low ice adhesion effect. Such coating thickness is not conducive to large-scale use. In addition, they usually rely on template method, spin coating method or multi-step preparation method, etc., which are difficult to be widely applied to various equipment surfaces due to the complexity of the preparation process. SUMMARY

[0005] In view of the problems of the prior art, the present application provides an anti-icing coating with high-efficiency crack initiation and rapid propagation promoting ability (i.e., crack-sensitive effect) and a preparation method thereof. The coating can be constructed in one step by spraying emulsion paint, and a thickness of only ~50μm is required to achieve efficient deicing based on the crack-sensitive effect.

[0006] The technical solution of the present application is as follows:

[0007] A crack-sensitive high-efficiency deicing coating, comprising a soft hydrophobic coating body and a hard particle phase with high cross-linking density inside the coating.

[0008] Preferably, the soft hydrophobic coating body is a flexible resin; the hard particle phase with high cross-linking density inside the coating is generated after the cross-linking reaction of organic polysilazane resin (OPSZ) and the water phase in the emulsion coating.

[0009] Preferably, the flexible resin is a room temperature curing silicone resin, an oily polyurethane or a fluorinated silicone resin.

[0010] Preferably, the hard particle phase generated by the cross-linking reaction has a uniform particle size (~5-20 μm) and is randomly distributed inside the flexible coating; this random distribution (close to or far from the upper surface of the coating) causes the surface of the coating to exhibit a heterogeneous modulus distribution.

[0011] Preferably, the Young's modulus of the soft hydrophobic coating body is close to the intrinsic modulus of the silicone resin, being 1-3 MPa; the part of the coating containing the hard particle phase has a higher Young's modulus, ranging from 5 to 20 MPa.

[0012] The preparation method of the above-mentioned crack-sensitive high-efficiency deicing coating is based on spraying method, comprising the following steps:

[0013] Step 1: Preparation of oil phase solution.

[0014] A hydrophobic flexible resin is selected as the film-forming material, and 4 parts of the hydrophobic flexible resin are taken as the basis; an organic solvent having phase solubility with the film-forming material but not miscible with water, a surfactant for water-in-oil emulsion, and an anti-settling agent suitable for oil-based coatings are selected; the above materials are mixed and stirred at 40-50°C for 20-30 min to form a uniform solution, and then cooled to room temperature for standby.

[0015] Preferably, the organic solvent having phase solubility with the film-forming material but not miscible with water is taken in an amount of 8-10 parts; the surfactant for water-in-oil emulsion is taken in an amount of 0.04-0.12 parts; and the anti-settling agent suitable for oil-based coatings is taken in an amount of 0.1-0.25 parts.

[0016] Preferably, the hydrophobic flexible resin is a room temperature curing silicone resin, an oily polyurethane or a fluorinated silicone resin; the organic solvent is butyl acetate, ethyl acetate or xylene, and the amount can be appropriately increased or decreased to adjust the viscosity of the coating; the surfactant is preferably an oil-soluble surfactant with an HLB value of 3-6, such as Span 20, Span 60, Span 80 or PEG-30 dipolyhydroxystearate; and the anti-settling agent is preferably an oil-soluble long-chain polymer product, such as polyamide wax, modified polyurea solution, etc.

[0017] Step 2: Preparation of aqueous phase solution.

[0018] Take 3.5-10 parts of pure water, add water-based thickening surfactant to adjust the viscosity of the aqueous phase, and stir uniformly at room temperature to form an aqueous phase solution.

[0019] Preferably, the water-based thickening surfactant is a small molecule sodium polyacrylate (Mw: 4000-8000), and the addition amount is 1-5wt% of pure water.

[0020] Step 3: Mixing of emulsion paint.

[0021] The aqueous phase solution obtained in step 2 is added to the oil phase solution obtained in step 1, and stirred at room temperature for 20-30 min to form the final emulsion paint.

[0022] Step 4: Addition of crosslinking agent before spraying.

[0023] Add resin curing agent and 0.1-0.4 parts of room temperature curing organic polysilazane resin (OPSZ, solid content >98%) to the emulsion paint obtained in step 3; after stirring at room temperature for 10-20 min, spray.

[0024] Preferably, the amount of resin curing agent is 0.4-0.6 parts.

[0025] Step 5: Implementation of spraying.

[0026] Take the emulsion paint after adding the crosslinking agent in step 4 and place it in a low-pressure spray gun cup, and spray it on the target substrate. By controlling the spraying parameters (such as spraying air pressure, spraying distance, spraying stroke, moving speed, spraying width, and paint consumption, etc.), the thickness and roughness of the coating film can be controlled.

[0027] Step 6: Crosslinking and curing of the coating.

[0028] Place the sprayed surface in a well-ventilated room at room temperature for natural curing. As the solvent evaporates, the flexible resin is crosslinked and cured into a low-modulus coating body; the OPSZ component is crosslinked in situ with the water phase droplets in the emulsion paint to form a high-modulus hard phase; finally, a crack-sensitive and efficient deicing coating is formed.

[0029] Advantages of the present application:

[0030] (1) The present application provides an environmentally friendly anti-icing coating formula, which can be used to prepare a light and thin (~50μm) anti-icing coating on any equipment surface by manual / mechanical spraying.

[0031] (2) The present application realizes a one-step construction of an elastic modulus heterogeneous anti-icing coating by in-situ cross-linking at the interface of emulsion. This cross-linking path makes the droplets in the emulsion become hard particles with uniform particle size (~5-20 μm) and random distribution in the flexible coating.

[0032] (3) The high-efficiency deicing coating prepared by the present application has a crack sensitivity effect. When the accumulated ice attached to the surface of the coating is subjected to external force / gravity, the high-modulus points on the surface of the coating can amplify the local stress and promote the flexural deformation of the surrounding softer parts to generate interface micro-cracks; a large number of interface micro-cracks as defects of the adhesion interface can greatly reduce the ice adhesion strength, and under the continuous action of external force / gravity, accelerate the expansion and merging, thereby realizing the efficient ice-coating interface fracture.

[0033] (4) The high-efficiency deicing coating proposed by the present application has a cross-scale interface fracture promotion capability. Under the condition of large-scale adhesion, the coating can induce the aggregation and merging of micro-cracks to form macro-cracks and promote their rapid propagation along the interface, thereby realizing the efficient fracture of the large-scale ice adhesion interface.

[0034] (5) The high-efficiency deicing coating proposed by the present application has excellent static passive deicing performance. The square tray (size about 32x16 cm) sprayed with the coating can realize the spontaneous shedding of the 1 cm thick ice layer relying on gravity; this means that the surface sprayed with the coating can spontaneously shed the accumulated ice of a larger area relying on gravity.

[0035] (6) The high-efficiency deicing coating proposed by the present application has excellent dynamic passive deicing performance. The unmanned aerial vehicle rotor sprayed with the coating can easily shake off the accumulated ice on the rotor blades relying on centrifugal force, and its deicing effect is significantly better than that of the commercial super-hydrophobic coating (NeverWet); the coating is expected to be applied to the blades of wind turbines, helicopter propellers, etc. and realize efficient passive deicing.

[0036] (7) The present application provides a basic framework for designing anti-icing coatings based on emulsion coatings, which can realize the development of mechanical robustness and modulus heterogeneous anti-icing coatings by replacing film-forming resin types, regulating liquid phase components, etc. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is the main composition of the emulsion coating and the formation process of the modulus heterogeneous coating proposed by the present application. In the figure, the organic silicon polymer chain is cross-linked and solidified into a low-modulus coating body; the OPSZ component is in-situ cross-linked with the aqueous droplets in the emulsion coating to form a high-modulus hard phase.

[0038] Figure 2 is the structural formula of OPSZ and the reaction process of forming a highly cross-linked network structure; wherein R is an organic functional group, such as -CH3, etc.

[0039] Figure 3 The morphology and modulus distribution of the coating prepared in Example 1 are characterized; wherein a is the surface morphology of the coating; b is the internal phase distribution of the coating; c is the elastic modulus distribution of the surface of the coating (measured by atomic force microscopy), which proves the modulus heterogenization distribution of the surface thereof.

[0040] Figure 4 The schematic diagram of the mechanism of inducing interface microcracks of the high-efficiency deicing coating prepared in the application.

[0041] Figure 5 The schematic diagram of the experimental device for testing the ice adhesion properties of the sample and observing the evolution of the interface cracks.

[0042] Figure 6 The interface crack evolution process of the three coatings in Example 1, Comparative Example 1 and Comparative Example 2 during deicing.

[0043] Figure 7 The deicing property analysis of the three coatings in Example 1, Comparative Example 1 and Comparative Example 2; wherein a is the force-time change curve of the three coatings during the test of ice adhesion of a small size (15x15mm); b is the traction-separation curve (i.e. strength-displacement curve) during shear deicing, and the peak value of the curve represents the maximum shear strength, and the area of the curve represents the interface fracture energy during deicing; c is the ice adhesion strength and deicing work of the three surfaces.

[0044] Figure 8 The deicing forces of the crack-sensitive coating prepared in the application and the most advanced low-interface toughness coating (Science. 2019, 364: 371-375) at different ice adhesion interface lengths are compared (unit width deicing force).

[0045] Figure 9 The interface crack propagation process of the crack-sensitive coating prepared in Example 2 during the removal of 20cm long ice.

[0046] Figure 10 The ice tray self-weight shedding experiment of the coating prepared in Example 3; wherein a is the tray sprayed with the crack-sensitive coating proposed in the application, which can easily realize the self-weight shedding of the ice layer; b is the tray sprayed with the flexible silicone coating in Comparative Example 1, and the ice adhesion is firm, and the ice layer can be removed only by shaking.

[0047] Figure 11Dynamic de-icing performance of the rotors with different coatings in Example 4 in the environment of-15°C (rotor speed ~ 2880 rpm). a is the process of ice layer shedding during the rotation of the blade shot by the high-speed camera, and the results show that the blades sprayed with the crack-sensitive coating are the first to remove the ice; b is the de-icing effect of the rotor in the continuous icing environment, the vertical axis represents the ice thickness at the radius of 5 cm of the rotor (circle in the inset), and the fan blade with the crack-sensitive coating has the highest de-icing frequency and the smallest ice shedding thickness in the time of 160 min.

[0048] Figure 12 Elastic modulus distribution of different coating surfaces; a-c are the elastic modulus distribution of the flexible silicone coating (from Comparative Example 1), the OPSZ-0 coating (from Example 5), and the OPSZ-0.6 crack-sensitive coating (from Example 5, the same as Example 1), respectively.

[0049] Figure 13 De-icing characteristic curves of the coatings with different OPSZ contents in Example 5; the OPSZ contents of a-e are 0 g, 0.2 g, 0.4 g, 0.6 g (the same as Example 1), 0.8 g, respectively, and the bold curve is the average curve of the remaining curves.

[0050] Figure 14 De-icing performance comparison of the coatings with different water phase mass fractions in Example 6; E20, E30, and E40 correspond to water phase mass fractions of 20 wt%, 30 wt% (the same as Example 1), and 40 wt%, respectively.

[0051] Figure 15 De-icing performance comparison of the coatings with different surface roughnesses in Example 7; the root mean square roughnesses (S q ) of the coatings R1, R2, and R3 are ~1.32 μm, ~1.46 μm, and ~1.55 μm, respectively. DETAILED DESCRIPTION

[0052] The specific embodiments of the present application will be further described below in conjunction with the drawings and technical solutions.

[0053] As Figure 1 shown, the crack-sensitive high-efficiency de-icing coating prepared based on the spraying method provided by the present application is prepared by formulating a special emulsion coating and spraying, to form a soft and hard two-phase component coating with different cross-linking densities; the soft matrix is formed by the hydrophobic film-forming resin in the coating, and the hard particle phase embedded in the soft matrix is generated by the reaction of the aqueous droplets and the organic polysilazane resin (OPSZ) in the coating, and the reaction mechanism is as Figure 2The distribution density of the hard phase can be controlled by the mass fraction of the water phase in the emulsion, and the modulus difference of the coating surface and the overall average modulus can be controlled by adjusting the OPSZ content.

[0054] The emulsion coating is a water-in-oil emulsion, and a non-ionic surfactant with a low HLB value (3-6) (such as Span 80) is preferably used to stabilize the emulsion interface. An oil-soluble long-chain polymer product (such as polyamide wax, modified polyurea solution, etc.) is preferentially selected as a de- sedimentation agent to form a space network structure in the coating solution to increase the thixotropy of the solution, and to help the suspension of droplets in the emulsion; in addition, it has the effect of preventing sagging when sprayed on a vertical wall. The mass fraction of the water phase in the emulsion coating should be controlled at 20-50 wt%, too little is not conducive to the formation of a stable emulsion, and too much can easily destroy the film continuity or cause phase inversion (become an oil-in-water emulsion). A small amount of water-soluble surfactant can be added to the water phase solution for thickening, and a small molecule sodium polyacrylate (Mw about 5000) is preferably used.

[0055] The silicone resin used in the following examples was purchased from Ausbon (China) Co., Ltd., model 195T; Span 80 was purchased from Aldrich, non-ionic surfactant; polyamide wax de-sedimentation agent was purchased from Shenzhen Jitian Chemical Co., Ltd., model 6900-20X; organopolysilazane resin was purchased from Shenzhen Weijing High-tech Materials Technology Co., Ltd., model NS3620; sodium polyacrylate was purchased from Aldrich, 45% aqueous solution, Mw≈4500.

[0056] Example 1

[0057] A crack-sensitive coating was first prepared by adding 8 g of silicone resin precursor, 0.16 g of Span 80 and 0.4 g of polyamide wax de-sedimentation agent into 20 g of butyl acetate, and using a magnetic stirrer to stir at a high speed (~1500 rpm) at 40°C for 30 min to form an oil phase solution and then cooled to room temperature. Then 12 g of deionized water (containing 3 wt% of sodium polyacrylate) was added and stirred at a high speed for 30 min to form an emulsion coating with a mass fraction of 30 wt%. Before spraying, 1.2 g of silicone resin curing agent and 0.6 g of organopolysilazane resin (OPSZ) were added and stirred at a high speed for 15 min. A low-pressure spray gun (Yamada, LPH-80) was used to spray the mixture onto the surface of a clean glass sheet (75x25x1mm), and then air-dried at room temperature for 3 days to ensure complete curing. The spraying process followed fixed process parameters such as spraying distance, spraying stroke, spraying width, moving speed, spraying air pressure, etc., and the spraying times (or coating amount) were adjusted to control the coating thickness at ~50 μm. The formed coating had a continuous surface (Fig. 1a), and the hard phase particles inside were mainly distributed in the size range of 10-15 μm (Fig. 1b). Figure 3 a), the size of the hard phase particles inside was mainly distributed in the range of 10-15 μm (Fig. 1b). Figure 3b); the difference in modulus of elasticity exhibited by the surface is determined by the position of the hard phase particles in the coating (random) and the flexible matrix, in which the modulus of elasticity of the flexible matrix is 2 MPa, and the modulus of elasticity of the hard phase is 5-10 MPa Figure 3 c). The schematic diagram of the principle of inducing interface crack nucleation by stress concentration sites in the coating during the deicing process is shown in Figure 4 .

[0058] Comparative Example 1

[0059] A control sample, a flexible silicone coating without hard phase particles, was prepared. 24 g of butyl acetate was mixed with 8 g of silicone resin precursor, and 0.32 g of polyamide wax was added, and after being fully stirred at 40°C, it was cooled to room temperature; 1.2 g of silicone resin curing agent was added before spraying and stirred for 15 min. The spraying followed the same process steps as Example 1, and finally a flexible silicone coating with a thickness of ~50 μm was obtained.

[0060] Comparative Example 2

[0061] A control sample, a hardened silicone resin coating (without hard phase particles), was prepared. Based on the preparation method of Comparative Example 1, 0.6 g of OPSZ (same amount as Example 1) was added at the same time as the 1.2 g of silicone resin curing agent before spraying, and stirred for 15 min, and the spraying followed the same process steps as Example 1, and finally a hardened silicone coating with a thickness of ~50 μm was obtained.

[0062] The samples prepared in Example 1, Comparative Example 1 and Comparative Example 2 were tested for deicing properties, as shown in Figure 5 , the sample to be tested was fixed on a refrigeration table at -10°C, and an ice block with a size of 15x15x6 mm was frozen on the surface of the sample, and a force gauge was installed on a motorized sliding table to move at a constant speed of 0.1 mm / s, and the push head of the force gauge was 3 mm away from the surface of the sample; at the same time, a high-speed camera was used to record the evolution process of the interface crack during deicing above the ice block, in order to ensure clear imaging, deionized water treated by degassing was used when freezing the ice block, and nitrogen was introduced into the transparent acrylic cover to ensure dry air, so as to avoid the influence of frost on the surface of the ice block on the clarity of the shot.

[0063] The three samples of Example 1, Comparative Example 1 and Comparative Example 2 were numbered as S1, S2 and S3, respectively, and their interface crack evolution behaviors were as shown in Figure 6The interface crack of the crack-sensitive coating has multiple nucleation sites and super-fast propagation, fully penetrating the interface in only 560 ms, and the ice and coating are instantaneously separated; while the flexible silicone coating exhibits fewer crack initiation sites and slow crack propagation, and the crack has not yet penetrated the interface at 4800 ms; compared with S1, the hardened silicone coating needs more time to accumulate power for crack initiation, and its crack area at t = 450 ms is comparable to that in S1 at t = 300 ms, and finally the coating completes interface fracture in 830 ms.

[0064] Figure 7 Fig. a shows the force-time curve of the above three coatings during ice removal, wherein the coating S1 (crack-sensitive coating) has the lowest peak ice removal force and the fastest ice-coating separation speed (~1.5 s); Figure 7 Fig. b is the traction-separation curve of the three surfaces, and the area under the curve represents the ice removal fracture energy; Figure 7 Fig. c compares the ice adhesion strength and ice removal work of the three surfaces, and sample S1 realizes the combination of low ice adhesion strength and low ice removal work consumption by virtue of its crack-sensitive effect.

[0065] Example 2

[0066] Scale effect test of crack-sensitive coating ice removal. First, the crack-sensitive coating is prepared according to the steps in Example 1, and the coating is sprayed on a glass substrate with a size of 21 cm x 5 cm x 1 mm. The prepared sample is tested according to the ice adhesion test method in Figure 5 , after the ice blocks with a width of 1 cm, a height of 0.6 cm, but different lengths (1-20 cm) are frozen on the surface of the sample, the ice removal test is carried out, and the peak force of ice removal is recorded. The experimental results are compared with the most advanced low interfacial toughness coating (Science. 2019, 364: 371-375), and the results are shown in Figure 8 , the crack-sensitive coating has smaller ice removal force at all adhesion lengths, and its stable value is ~32.8 N / cm, which is very close to the van der Waals limit (32 N / cm); in addition, the slope of the oblique line represents the ice adhesion strength of the coating, and these results prove the excellent scale ice removal ability of the crack-sensitive coating of the present application.

[0067] Figure 9 The propagation process of the interface crack of the crack-sensitive coating when removing the 20 cm long ice layer is shown. The microcrack cluster at position (t = 150 ms), at t = 240 ms, the microcrack clusters are interconnected to form a macrocrack, and at this time, a new microcrack cluster is formed at position ; with the transmission of stress, a new microcrack cluster is formed at position The coalescence of microcracks also occurs to form macrocracks that propagate forward. This process reveals the microscopic mechanism of how crack-sensitive coatings achieve efficient fracture of the ice-adhered interface at large scales.

[0068] Example 3

[0069] Large-scale ice tray experiment. Prepare a PET material (hard and not easy to deform) tray with a size of ~32x16x3 cm, and according to the method steps of Example 1 and Comparative Example 1, respectively, spray the coating on the two PET trays, and finally obtain the tray coated with the crack-sensitive coating and the tray coated with the flexible silicone coating. Place the above two trays in the freezing layer of the refrigerator (−18℃) and level them, add an equal amount of water, and ensure that the water level in the tray is about 9 mm high, freeze for 48 h, and then carefully take out the tray with the bottom held by hand. As shown in FIG. 8a, place the frozen ice tray vertically as the starting position, and then gently turn it over. When the tray coated with the crack-sensitive coating is slightly tilted, the ice layer easily falls off; while the tray with the flexible silicone coating still has ice adhering to the tray even if it has been turned over with the opening facing down, and needs to be shaken up and down several times before it can fall off (see FIG. 8b). Figure 10 Figure 10

[0070] Example 4

[0071] Dynamic ice removal performance test of crack-sensitive coating. Different types of anti-icing coatings were prepared on a three-blade unmanned aerial vehicle rotor with a diameter of 5 inches: crack-sensitive coating was prepared by spraying on both sides of one blade according to the method steps of Example 1; on the adjacent blade, a commercial superhydrophobic coating (Rust-Oleum Inc., NeverWet) was sprayed on both sides, and the construction process followed the product instructions; the other blade was not treated and used as a blank control. The rotor was installed on a brushless motor and placed in an environmental chamber at −15℃ to run continuously at a speed of ~3000 rpm, while a motorized atomizer was used to provide water mist in the environmental chamber, and the fan surface would gradually accumulate ice, until the ice reached the critical mass and was removed under the action of centrifugal force by overcoming the adhesion to the substrate, and a high-speed camera was used to record the process.

[0072] Figure 11 FIG. 8a compares the ice removal performance of rotor blades with different coatings, in which the blade with the crack-sensitive coating removes the accumulated ice first. Figure 11 ​​Figure b illustrates the cyclic de-icing effect of the rotor in a continuously icing environment. The vertical axis represents the ice thickness at a rotor radius of 5 cm (circled in the inset). The curve increases to indicate that the blades are continuously icing, and a sudden drop in the curve indicates that the ice is detached. Over a period of 160 minutes, the blades with the crack-sensitive coating exhibited the highest de-icing frequency and the smallest ice detachment thickness. Furthermore, the results at 146.5 minutes in the inset show that all the ice on the surface of the blades with the CSS coating was removed, while the blades with the commercial superhydrophobic coating (SHS) still had half of the ice remaining on their surface.

[0073] Example 5

[0074] The OPSZ content can affect the crosslinking density / hardness of the hard phase in the coating of this invention, thereby affecting the de-icing performance of the coating. Therefore, this embodiment demonstrates the effect of OPSZ dosage. Five samples with different OPSZ contents were prepared according to the method steps in Example 1. Specifically, "adding 0.6g OPSZ" in Example 1 was replaced with adding 0g / 0.2g / 0.4g / 0.6g / 0.8g OPSZ, respectively. The five prepared coating samples were labeled as OPSZ-0 / 0.2 / 0.4 / 0.6 / 0.8.

[0075] The elastic modulus distribution of the surfaces of samples OPSZ-0, OPSZ-0.6, and the flexible silicone coating is as follows: Figure 12 As shown in the figure. The results indicate that the flexible silicone coating has the most uniform surface modulus, with an average modulus of ~2 MPa; OPSZ-0.6 (the sample in Example 1) exhibits the greatest degree of modulus heterogeneity; in contrast, the modulus distribution of OPSZ-0 falls between the two. This result also demonstrates the process by which OPSZ crosslinks with the aqueous phase to generate a hard particulate phase.

[0076] according to Figure 5 The test method described above involved performing nine ice adhesion tests on each sample. The load-time curves of the de-icing process are summarized in [the table / document / reference needed]. Figure 13 In the figure, the bolded curve is the average curve of 9 tests. Compared with the sample (OPSZ-0.6) in Example 1, the peak de-icing force of OPSZ-0 is only one-third of that of the sample, but the de-icing time is about 3 times longer; compared with the de-icing curve of the flexible silicone coating ( Figure 7 In (a, S2), OPSZ-0 still exhibits significant de-icing advantages. As the OPSZ content increases, the peak de-icing force gradually rises, while the de-icing time gradually decreases. Until OPSZ reaches 0.8g, the de-icing force suddenly increases to twice that of OPSZ-0.6, and the de-icing time also begins to increase. Its de-icing characteristics are quite similar to those of hardened silicone coatings. Figure 7The results show that the crack-sensitivity effect of the coating is significant, or the de-icing peak force is greatly reduced, or the interfacial fracture efficiency is greatly improved (i.e. shorter de-icing time) when the OPSZ content is not more than 0.6 g.

[0077] Example 6

[0078] The water phase content in the coating formulation provided by the present application affects the amount of hard phase inside the coating, thereby affecting the modulus distribution characteristics of the coating. Therefore, this example demonstrates the influence of the water phase content on the de-icing performance of the coating. Three samples with different water phase contents were prepared according to the method steps in Example 1, specifically, the "add 12 g of deionized water (containing 3 wt% sodium polyacrylate)" in Example 1 was replaced by adding 7 g / 12 g / 18.7 g of deionized water (containing 3 wt% sodium polyacrylate), respectively. The three prepared coatings were named E20, E30 and E40, respectively. The above samples were tested according to the test method in Figure 5 , and the de-icing performance is summarized in Figure 14 . Among them, E20 has the largest ice adhesion strength and de-icing work, while E30 and E40 have similar ice adhesion strength, and E40 has slightly higher de-icing work. This shows that E20 may lack sufficient stress concentration phase (hard phase particles) to achieve crack-sensitivity effect.

[0079] Example 7

[0080] Surface roughness is an intrinsic property of the coating preparation, and also affects the adhesion characteristics of the ice-substrate interface. This example demonstrates the optimization process of adjusting the surface roughness on the de-icing performance of the coating of the present application. Three samples with different surface roughness were prepared according to the method steps in Example 1 and adjusting the spraying process (the control of roughness is mainly achieved by adjusting the spraying process). The surface roughness of the prepared coating was detected by a white light interferometer, and the root mean square roughness (S q ) of the three surfaces was ~1.32 μm, ~1.46 μm, ~1.55 μm, respectively, named R1, R2, R3. The above samples were tested according to the test steps in Figure 5 , and the de-icing performance is summarized in Figure 15 . The ice adhesion strength of the medium roughness sample R2 is similar to that of R1, but its de-icing work is much smaller than that of R1, and the ice adhesion strength and de-icing work of the sample R3 with the largest roughness are appropriately increased. This shows that appropriate roughness does not significantly increase the ice adhesion strength, and is also conducive to greatly reducing the de-icing work, but excessive roughness will slightly reduce the de-icing effect. Therefore, the crack-sensitive coating of the present application can further fine-tune the surface roughness to improve the de-icing performance. In addition, the surface roughness of the coating is determined by multiple factors such as coating formulation, spraying process, drying conditions, etc. The practitioner can fine-tune the coating formulation, spraying process to adjust the surface roughness to optimize the de-icing performance under specific construction environment.

[0081] The present application is not limited to the above-mentioned embodiments, and those skilled in the art can add conventional auxiliaries (such as surfactants, anti-settling agents, leveling agents, defoaming agents, etc.) or adjust the amounts of these auxiliaries and resin curing agents, or replace the resins used in the present application with similar resin products, as needed, without departing from the spirit of the present application, and these modifications and replacements shall still fall within the protection scope of the present application.

Claims

1. A crack sensitive high-efficiency de-icing coating, characterized in that, The soft hydrophobic coating body and the hard particle phase with high cross-linking density inside the coating; the soft hydrophobic coating body is a flexible resin; the hard particle phase with high cross-linking density inside the coating is generated after the cross-linking reaction of the organic polysilazane resin OPSZ and the water phase in the emulsion coating; the hard particle phase generated by the cross-linking reaction has a uniform particle size and is randomly distributed inside the flexible coating; The flexible resin is a room temperature curing silicone resin, an oily polyurethane or a fluorinated silicone resin; The emulsion coating is prepared by mixing the oil phase solution of the flexible resin and the water phase solution containing the water-based thickening surfactant, and the emulsion coating is a water-in-oil emulsion.

2. The crack sensitive high-efficiency de-icing coating according to claim 1, characterized in that, The Young's modulus of the soft hydrophobic coating body is 1-3 MPa; and the Young's modulus of the part containing the hard particle phase inside the coating is 5-20 MPa.

3. A method of producing a crack-sensitive high-efficiency de-icing coating according to claim 1 or 2, characterized in that Based on the spraying method, the steps include: Step 1: preparation of the oil phase solution; A hydrophobic flexible resin is selected as the film-forming material, and 4 parts of the hydrophobic flexible resin are taken as the basis; an organic solvent which is miscible with the film-forming material but immiscible with water, a surfactant for water-in-oil emulsion, and an anti-settling agent suitable for oily coatings are selected; the above materials are mixed and stirred at 40-50 DEG C for 20-30 min to form a uniform solution, and then cooled to room temperature for standby; Step 2: preparation of the water phase solution; 3.5-10 parts of pure water are taken, and the water-based thickening surfactant is added to adjust the viscosity of the water phase; after stirring uniformly at room temperature, a water phase solution is formed; Step 3: mixing of the emulsion coating; The water phase solution obtained in step 2 is added to the oil phase solution obtained in step 1, and high-speed stirring is carried out at room temperature for 20-30 min to form the final emulsion coating; Step 4: addition of the cross-linking agent before spraying; The resin curing agent and 0.1-0.4 parts of room temperature curing organic polysilazane resin OPSZ are added to the emulsion coating obtained in step 3; after high-speed stirring at room temperature for 10-20 min, spraying is carried out; Step 5: implementation of spraying; The emulsion coating after adding the cross-linking agent in step 4 is placed in a low-pressure spray gun cup, and spraying is carried out on the target substrate; the spraying parameters are controlled to realize the regulation of the coating thickness and roughness; Step 6: cross-linking and curing of the coating; The surface after spraying is placed at room temperature in a ventilated place for natural curing; as the solvent evaporates, the flexible resin is cross-linked and cured into a low-modulus coating body; the OPSZ component is cross-linked in situ with the water phase droplets in the emulsion coating to form a high-modulus hard phase; and finally a crack-sensitive and efficient deicing coating is formed.

4. The method of claim 3, wherein the coating is prepared by the steps of: The organic solvent which is miscible with the film-forming material but immiscible with water is taken in an amount of 8-10 parts; the surfactant for water-in-oil emulsion is taken in an amount of 0.04-0.12 parts; and the anti-settling agent suitable for oily coatings is taken in an amount of 0.1-0.25 parts.

5. The method for preparing a crack-sensitive, high-efficiency de-icing coating according to claim 3, characterized in that, The hydrophobic flexible resin is a room temperature curing silicone resin, an oily polyurethane or a fluorinated silicone resin; the organic solvent is butyl acetate, ethyl acetate or xylene; the surfactant is an oil-soluble surfactant with an HLB value of 3-6, specifically Span 20, Span 60, Span 80 or PEG-30 dipolyhydroxystearate; and the anti-settling agent is an oil-soluble long-chain polymer product, specifically a polyamide wax or a modified polyurea solution.

6. The method for preparing a crack-sensitive, high-efficiency de-icing coating according to claim 3, characterized in that, The aqueous thickening surfactant is a small-molecule polyacrylic acid sodium with a molecular weight of 4000-8000, and the addition amount is 1-5 wt% of pure water.

7. The method for preparing a crack-sensitive, high-efficiency de-icing coating according to claim 3, characterized in that, The amount of the resin curing agent is 0.4-0.6 parts.

8. The method for preparing a crack-sensitive, high-efficiency de-icing coating according to claim 3, characterized in that, The control of the spraying parameters includes spraying air pressure, spraying distance, spraying stroke, moving speed, spraying width and paint amount.

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