Water-based deicing coating and preparation method thereof

Abstract

The invention relates to a water-based deicing coating and a preparation method thereof. The coating comprises the following materials in parts by mass: 99-95 parts of a water-based polyurethane emulsion; 1-5 parts of triglyceride / silicone oil; and 1 to 5 parts of medium and long chain alkyl trimethoxy silane. The preparation method comprises the following steps: uniformly mixing waterborne polyurethane emulsion, triglyceride / silicone oil and medium-long chain alkyl trimethoxy silane, covering a matrix with the mixture through blade coating or spray coating, and curing to obtain the waterborne deicing coating. The synergistic effect of the triglyceride / silicone oil and the medium and long chain alkyl trimethoxy silane enables the coating to have excellent deicing performance. The preparation method of the coating has the characteristics of low raw material cost, simple and environment-friendly process and good coating quality; the coating has the characteristics of excellent deicing performance, firmness and durability.

Description

Technical Field

[0001] The present invention relates to an aqueous de-icing coating with low interfacial toughness and a preparation method thereof, belonging to the field of aqueous anti-icing coatings. Background Art

[0002] Surface icing and ice accretion cause huge economic losses and energy consumption in fields such as aviation, energy, and transportation, including commercial airliners, drones, high-voltage power transmission, wind turbines, and polar ships, bringing serious impacts and hazards. To solve the problems caused by surface icing and achieve the prevention and removal of ice accretion, two anti-icing strategies, active and passive, have been developed. Active anti-icing refers to preventing and removing ice accretion by inputting energy (mechanical energy, chemical energy, electrical energy, and thermal energy), including pneumatic belt de-icing, antifreeze de-icing, gas heating de-icing, and electrothermal anti-icing. The active anti-icing strategy has the characteristics of stable de-icing performance and high efficiency and is mainly used in industrial activities. However, it has the disadvantages of complex systems, increased weight, and high energy consumption. Therefore, in order to achieve simple, lightweight, low-energy-consuming, and high-efficiency anti-icing, the passive anti-icing strategy has become a research hotspot.

[0003] Passive anti-icing is achieved by preparing a coating on the surface of the protective substrate to prevent and remove ice. The anti-icing coating plays a role by preventing the formation of ice or reducing the adhesion between ice and the coating. Currently, various anti-icing coatings have been developed: superhydrophobic coatings, water-lubricating coatings, surface oil-lubricating coatings, low-modulus coatings, stress-concentration coatings, and low-interfacial-toughness coatings. However, currently, the main research and inventions mainly focus on superhydrophobic coatings and superhydrophobic coatings supplemented with active de-icing technologies. For example, Chinese Patent No. CN119286394A discloses a preparation method and application of a polydimethylsiloxane superhydrophobic anti-icing and de-icing material. PDMS / CNTs porous foam is prepared using polydimethylsiloxane and carbon nanotubes, and then the PDMS / CNTs porous foam is spray-modified with a CNTs / SiO2 superhydrophobic composite coating solution to prepare a superhydrophobic anti-icing and de-icing material. Chinese Patent No. CN118460105A discloses a superhydrophobic cement-based anti- / de-icing coating with high photothermal conversion performance and a preparation method thereof. A superhydrophobic coating with photothermal performance is prepared using carbon black, carbon nanotubes, organic solvents, surfactants, and prepolymer solutions, where carbon black and carbon nanotubes are used as photothermal materials.

[0004] However, in engineering applications, superhydrophobic coatings will quickly lose their deicing properties under low temperature and high humidity, mechanical wear and multiple icing / deicing cycles, and large-sized ice is difficult to remove. Golovin et al. first discovered that when the width and height of the ice layer are fixed, the deicing force of some polymer coatings first increases and then tends to be constant as the length of the ice layer increases. They proposed a mechanism for the transition of the cracking of the ice layer / coating interface from adhesion strength control to interface toughness control; this means that when the ice layer reaches a certain area, the deicing force of the coating controlled by interface toughness is smaller than that of other deicing coatings controlled by adhesion strength. Golovin et al. further designed and prepared a low interface toughness coating with a constant deicing force of 35N, and achieved the removal of large-sized ice (95cm×95cm×1cm) under its own gravity. However, the deicing force of the low interfacial toughness deicing coating on small-sized ice (1cm×1cm×0.6cm) is relatively large, and its ice adhesion strength (115kPa) is much greater than that of other deicing coatings (<100kPa); at the same time, the coating needs to be extremely soft (0.12MPa) and extremely thin (1-2μm) to have low interfacial toughness (0.12J / m 2 ), which results in poor mechanical durability.

[0005] In addition, the preparation of most current anti-icing coatings, including the low interface toughness coating mentioned above, relies on an organic solvent system with a high content of volatile organic compounds (VOCs), which poses a huge threat to the ecological environment. At the same time, due to the preparation characteristics of some coatings, for example, some super-hydrophobic coatings require precise laser micro-nano manufacturing technology, making it impossible to achieve anti-icing of curved surfaces by spraying. Summary of the invention

[0006] In view of the defects of the prior art, one of the objects of the present invention is to provide a water-based deicing coating, which is an aqueous polyurethane coating containing triglycerides / silicone oil and medium- and long-chain alkyl (C8 / C10 / C12 / C16) trimethoxysilane; the water-based deicing coating has the characteristics of excellent deicing performance and strong durability, and can be used for deicing and anti-icing in energy and transportation fields such as high-voltage transmission lines, aircraft rotors, and fan blades.

[0007] The second object of the present invention is to provide a method for preparing a water-based deicing coating. The method uses a one-step mixing method to prepare a mixture of water-based polyurethane emulsion, triglyceride / silicone oil and medium-chain alkyltrimethoxysilane. The mixture can be coated on a substrate by scraping and spraying, and then further cured to obtain a water-based deicing coating. The method has the advantages of low raw material cost, simple and environmentally friendly process and good coating quality.

[0008] In order to achieve the purpose of the present invention, the following technical solutions are provided.

[0009] An aqueous deicing coating, which is composed of triglyceride / silicone oil, medium and long-chain alkyltrimethoxysilane, and aqueous polyurethane, and the mass ratio is as follows: 99-95 parts of aqueous polyurethane emulsion, 1-5 parts of triglyceride / silicone oil, and 1-5 parts of medium and long-chain alkyltrimethoxysilane.

[0010] A preparation method of the aqueous deicing coating described in the present invention, and the steps are as follows:

[0011] (1) Add triglyceride / silicone oil and medium and long-chain alkyltrimethoxysilane to the aqueous polyurethane emulsion according to the mass ratio, and mix for a certain time at room temperature to obtain a uniform and non-layered mixture.

[0012] (2) Cover the substrate with the mixture by scraping or spraying;

[0013] (3) Cure the substrate covered with the mixture at the recommended curing temperature of the aqueous polyurethane emulsion to obtain a coating.

[0014] Preferably, the triglyceride in step (1) is glyceryl trioctanoate, and the silicone oil is benzyl silicone oil with a viscosity of 30-40 mPa·s.

[0015] Preferably, the medium and long-chain alkyltrimethoxysilane in step (1) is n-octyltrimethoxysilane, n-decyltrimethoxysilane, dodecyltrimethoxysilane, and hexadecyltrimethoxysilane.

[0016] Preferably, the mixing time in step (2) is 5 min.

[0017] Preferably, the thickness of the coating obtained in step (3) is 100-500 μm

[0018] Beneficial effects

[0019] (1) The aqueous deicing coating provided by the present invention has both low interfacial toughness (corresponding to a constant deicing force ≈ 33 N) and low ice adhesion strength (<100 kPa), making the coating conducive to the removal of ice of different sizes. This is due to the synergistic enhancement of the plasticizing effect of triglyceride / silicone oil and the hydrophobic effect of medium and long-chain alkyltrimethoxysilane. At the same time, the coating not only has excellent deicing performance but also has a long service life.

[0020] (2) The aqueous deicing coating provided by the present invention has a relatively large modulus (1.13 MPa) and a relatively large thickness (100-500 μm), making the coating have better mechanical durability.

[0021] (3) The preparation method provided by the present invention is a simple one-step mixing method, which can be carried out by scraping and spraying, achieving simple, rapid and large-scale preparation of the coating, and having obvious advantages in preparation time and cost.

[0022] (4) The deicing coating provided by the present invention is prepared in an aqueous solvent system without the need for organic solvents, having the advantage of being green and environmentally friendly. Description of the Drawings

[0023] Figure 1 Adhesion strength of small-sized ice layers for Examples 1-4 and Comparative Example 1 at -15°C

[0024] Figure 2 Deicing force of ice layers with different sizes for Example 5 and Comparative Example 2 at -15°C

[0025] Figure 3 Adhesion strength of ice layers with different sizes for Example 5 and Comparative Example 2 at -15°C

[0026] Figure 4 Variation of constant deicing force during freezing / deicing cycles for Example 5 and Comparative Example 2 at -15°C

[0027] Figure 5 Elastic modulus of Example 5 and Comparative Example 2

[0028] Figure 6 Ice accretion amount of Example 6 under simulated freezing rain environment at -10°C and -20°C Detailed Description of the Invention

[0029] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings and specific embodiments. Among them, the methods are all conventional methods unless otherwise specified, and the raw materials can all be obtained from public commercial channels unless otherwise specified.

[0030] In the following comparative examples and examples:

[0031] Raw material information: Waterborne polyurethane, Shanghai Macklin Biochemical Co., Ltd., solid content: 60%.

[0032] Testing Method

[0033] 1. Testing method for deicing force / ice adhesion strength:

[0034] (1) Place customized acrylic molds with different bottom areas (S) on the coating surface in a low-temperature test chamber (DW-40, Beijing Zhongkelu Construction Instrument Equipment Co., Ltd.) at -15°C and 80% RH. The width of the mold is fixed at 10 mm and the length is changed. Drop a certain volume of deionized water so that the height of the water is 10 mm and freeze for more than 3 h to form an ice layer on the sample surface.

[0035] (2) A dynamometer with a push rod (Imada ZP-50N, Imada Dynamometer Co., Ltd., Japan) was used to record the magnitude of the force. The bottom end of the push rod was about 1-2 mm away from the coating surface. During the de-icing process, an injection pump (SPLab01, Duko Industrial Technology (Shanghai) Co., Ltd., China) was used to control the moving speed of the coating at 0.1 mm / s. When the ice layer on the coating surface fell off, the injection pump was stopped, and the maximum force (Fmax) measured during the whole process was recorded and denoted as the de-icing force;

[0036] The ice adhesion strength (τ ice ) is calculated as follows:

[0037]

[0038] In the formula, S is the ice layer / coating contact area, that is, the bottom area of the acrylic mold

[0039] 2. Elastic modulus test method:

[0040] The elastic modulus of the coating was obtained through tensile stress-strain performance testing. The testing was carried out in accordance with the standard (GB / T 528-2009), and the tested coating thickness was 1 mm. A universal testing machine (HAK-3516D, Shenzhen Kexing Precision Instrument Co., Ltd.) was used for testing, and the tensile rate was 100 mm / min.

[0041] 3. Anti-icing performance test method:

[0042] To evaluate the anti-icing performance of the coating, the ice accretion amount (the mass of ice accretion per unit length of the high-voltage transmission line, g / m) of the coating in a freezing rain environment was tested on the high-voltage transmission line. The waterborne de-icing coating was sprayed on the high-voltage transmission line, and the coating thickness was about 100 μm. The test was carried out in a low-temperature test chamber (DW-40, Beijing Zhongkelu Construction Instrument and Equipment Co., Ltd.), and -10°C and -20°C were set respectively, and the relative humidity was constantly controlled at 80% RH. Before the test, the high-voltage transmission line with the coating was precooled in the test environment for 12 hours. A spray system was used to spray water at 0°C on the horizontally placed high-voltage transmission line at a fixed height of 10 cm and a spraying inclination angle of 30° (the angle between the nozzle and the vertical direction). Test parameters: initial flow rate 7 m / s, simulated rainfall 1 mm / h, and continuous testing for 8 hours.

[0043] Example 1

[0044] A waterborne de-icing coating, and the preparation steps of the waterborne de-icing coating are as follows:

[0045] (1) Add an aqueous polyurethane emulsion, benzyl silicone oil with a viscosity of 30 - 40 mPa·s, and n-decyltrimethoxysilane into a centrifuge tube according to a mass ratio of 99:1:1. Place the centrifuge tube on a vortex mixer and mix at 2800 rpm for 5 min at room temperature until a uniform and stable mixture is formed.

[0046] (2) Use the doctor blade method to uniformly coat the mixture on the surface of the cleaned aluminum alloy substrate, and control the coating thickness to ensure that the final coating thickness meets the requirements;

[0047] (3) Place the coated substrate in a thermostatic and humidistatic chamber (30°C, 50% RH) for curing for 10 hours to finally obtain an aqueous de-icing coating with a thickness of about 500 μm.

[0048] Example 2

[0049] An aqueous de-icing coating, and the preparation steps of the aqueous de-icing coating are as follows:

[0050] (1) Add an aqueous polyurethane emulsion, benzyl silicone oil with a viscosity of 30 - 40 mPa·s, and n-decyltrimethoxysilane into a centrifuge tube according to a mass ratio of 95:5:5. Place the centrifuge tube on a vortex mixer and mix at 2800 rpm for 5 min at room temperature until a uniform and stable mixture is formed.

[0051] (2) Use the doctor blade method to uniformly coat the mixture on the surface of the cleaned aluminum alloy substrate, and control the coating thickness to ensure that the final coating thickness meets the requirements;

[0052] (3) Place the coated substrate in a thermostatic and humidistatic chamber (30°C, 50% RH) for curing for 10 hours to finally obtain an aqueous de-icing coating with a thickness of about 500 μm.

[0053] Example 3

[0054] An aqueous de-icing coating, and the preparation steps of the aqueous de-icing coating are as follows:

[0055] (1) Add an aqueous polyurethane emulsion, glyceryl trioctanoate, and n-decyltrimethoxysilane into a centrifuge tube according to a mass ratio of 99:1:1. Place the centrifuge tube on a vortex mixer and mix at 2800 rpm for 5 min at room temperature until a uniform and stable mixture is formed.

[0056] (2) Use the doctor blade method to uniformly coat the mixture on the surface of the cleaned aluminum alloy substrate, and control the coating thickness to ensure that the final coating thickness meets the requirements;

[0057] (3) Place the coated substrate in a thermostatic and humidistatic chamber (30°C, 50% RH) for curing for 10 hours to finally obtain an aqueous de-icing coating with a thickness of about 500 μm.

[0058] Example 4

[0059] An aqueous de-icing coating, and the preparation steps of the aqueous de-icing coating are as follows:

[0060] (1) Add an aqueous polyurethane emulsion, glyceryl trioctanoate, and n-decyltrimethoxysilane into a centrifuge tube according to a mass ratio of 95:5:5. Place the centrifuge tube on a vortex mixer and mix at 2800 rpm at room temperature for 5 min until a uniform and stable mixture is formed.

[0061] (2) Use a doctor blade method to uniformly coat the mixture on the surface of the cleaned aluminum alloy substrate, and control the coating thickness to ensure that the final coating thickness meets the requirements;

[0062] (3) Place the coated substrate in a thermostatic and humidistatic chamber (30 °C, 50% RH) for curing for 10 hours to finally obtain an aqueous de-icing coating with a thickness of about 500 μm.

[0063] Example 5

[0064] An aqueous de-icing coating, and the preparation steps of the aqueous de-icing coating are as follows:

[0065] (1) Add an aqueous polyurethane emulsion, glyceryl trioctanoate, and n-decyltrimethoxysilane into a centrifuge tube according to a mass ratio of 95:5:5. Place the centrifuge tube on a vortex mixer and mix at 2800 rpm at room temperature for 5 min until a uniform and stable mixture is formed.

[0066] (2) Use a doctor blade method to uniformly coat the mixture on the surface of the cleaned aluminum alloy substrate, and control the coating thickness to ensure that the final coating thickness meets the requirements;

[0067] (3) Place the coated substrate in a thermostatic and humidistatic chamber (30 °C, 50% RH) for curing for 10 hours to finally obtain an aqueous de-icing coating with a thickness of about 100 μm.

[0068] Example 6

[0069] (1) Add an aqueous polyurethane emulsion, glyceryl trioctanoate, and n-decyltrimethoxysilane into a centrifuge tube according to a mass ratio of 95:5:5. Place the centrifuge tube on a vortex mixer and mix at 2800 rpm at room temperature for 5 min until a uniform and stable mixture is formed.

[0070] (2) Use a spraying method (nitrogen, 0.3 MPa) to uniformly coat the mixture on the surface of the high-voltage transmission line;

[0071] (3) Place the coated substrate in a thermostatic and humidistatic chamber (30 °C, 50% RH) for curing for 10 hours to finally obtain an aqueous de-icing coating with a thickness of about 100 μm.

[0072] Comparative Example 1

[0073] An aqueous ordinary coating, and the preparation steps of the aqueous ordinary coating are as follows:

[0074] (1) Adopt the scraping method to uniformly coat the aqueous polyurethane emulsion on the surface of the cleaned aluminum alloy substrate, and control the coating thickness to ensure that the final coating thickness meets the requirements;

[0075] (2) Place the coated substrate in a constant temperature and humidity chamber (30°C, 50% RH) for curing for 10 hours, and finally obtain an aqueous polyurethane coating with a thickness of about 500 μm.

[0076] Comparative Example 2

[0077] An aqueous ordinary coating, and the preparation steps of the aqueous ordinary coating are as follows:

[0078] (1) Adopt the scraping method to uniformly coat the aqueous polyurethane emulsion on the surface of the cleaned aluminum alloy substrate, and control the coating thickness to ensure that the final coating thickness meets the requirements;

[0079] (2) Place the coated substrate in a constant temperature and humidity chamber (30°C, 50% RH) for curing for 10 hours, and finally obtain an aqueous polyurethane coating with a thickness of about 100 μm.

[0080] The ice adhesion strengths of the aqueous deicing coatings described in Examples 1 to 4 and the aqueous ordinary coating described in Comparative Example 1 (the ice layer / coating contact area is 1 cm 2 ) were tested, as Figure 1 shown. The ice adhesion strengths of Examples 1 to 4 were 93 kPa, 67 kPa, 42 kPa, and 35 kPa respectively, and the reduction ranges were 77-91%, indicating that the aqueous deicing coatings showed excellent performance in removing small-sized ice layers compared with the aqueous ordinary coatings.

[0081] The deicing forces and ice adhesion strengths of the aqueous deicing coating described in Example 5 and the aqueous ordinary coating described in Comparative Example 2 on ice layers of different sizes (the ice layer / coating contact area is 1-13 cm 2 ) were tested, as Figure 2 and Figure 3 shown. As the ice layer / coating contact area increased continuously, the deicing forces of both the aqueous deicing coating and the aqueous ordinary coating showed a trend of first increasing and then tending to be constant, and their ice adhesion strengths decreased continuously. It indicates that as the ice layer size increases, there is a transition from adhesion strength control (the stage of increasing deicing force) to interface toughness control (the stage of constant deicing force) in the cracking of the coating / ice layer interface.

[0082] In the interface toughness control stage, the constant de-icing force (≈33 N) of the waterborne de-icing coating is only one-third of that of the waterborne ordinary coating (≈100 N). Since the magnitude of the constant de-icing force directly reflects the magnitude of the interface toughness, the interface toughness of the waterborne de-icing coating is much lower than that of the waterborne ordinary coating, indicating that the waterborne de-icing coating exhibits remarkable performance in removing large-sized ice layers. When the size of the ice layer continues to increase, the ice layer will be able to be spontaneously removed under its own gravity. It should be noted that the waterborne de-icing coatings described in Example 4 and Example 5 only differ in thickness, and the ice adhesion strength of the coating is closely related to its thickness. Therefore, the adhesion strengths of Example 4 (thickness ≈500 μm) and Example 5 (thickness ≈100 μm) for small-sized ice (ice layer / coating contact area = 1 cm 2 ) are different. This thickness dependence also applies to the difference in ice adhesion strength between Comparative Example 1 (thickness ≈500 μm) and Comparative Example 2 (thickness ≈100 μm).

[0083] To evaluate the performance durability of the waterborne de-icing coating, the change in the de-icing force (i.e., the constant de-icing force in the interface toughness control stage) of the waterborne de-icing coating described in Example 5 (thickness ≈100 μm) for large-sized ice layers (ice layer / coating contact area = 10 cm 2 ) under freeze / thaw cycles was tested to characterize its performance durability, as Figure 4 shown. In 30 freeze / thaw cycles, the de-icing force of the waterborne de-icing coating remained basically unchanged, indicating that its de-icing performance has excellent durability. The elastic modulus of the waterborne de-icing coating described in Example 5 and the waterborne ordinary coating described in Comparative Example 2 was further tested, as Figure 5 shown. The elastic modulus of the waterborne de-icing coating was 1.13 MPa, which was 57% of that of the waterborne ordinary coating, but was 9.4 times that of the low-interface-toughness coating (0.12 MPa, constant de-icing force = 35 N) reported in past literature, indicating that the waterborne de-icing coating has higher mechanical strength. It should be noted that the thickness (100 μm) of the waterborne de-icing coating described in Example 5 (constant de-icing force = 33 N) is much greater than that reported in the literature (1 - 2 μm). This indicates that the waterborne de-icing coating not only has excellent de-icing performance, but also has excellent performance durability. In addition, its higher modulus and thickness significantly enhance its mechanical impact resistance.

[0084] To systematically evaluate the anti-icing performance of the waterborne de-icing coating, the ice accretion amount of the waterborne de-icing coating described in Example 6 under simulated freezing rain environments (-10°C and -20°C, 80% RH) was tested, as Figure 6As shown. At -10°C, the ice accretion amount of the coated high-voltage transmission line is 13 g / m, which is reduced by 72% compared with the uncoated high-voltage transmission line; at -20°C, its ice accretion amount is 25 g / m, and a significant reduction of 55% is still achieved. It fully shows that the water-based de-icing coating exhibits excellent anti-icing performance in a low-temperature and high-humidity environment.

[0085] The above are only specific embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An aqueous deicing coating, characterized in that: The water-based deicing coating is composed of triglyceride / silicone oil, medium-long chain alkyltrimethoxysilane, and water-based polyurethane, and the mass ratio is as follows: 99 - 95 parts of water-based polyurethane, 1 - 5 parts of triglyceride / silicone oil, and 1 - 5 parts of medium-long chain alkyltrimethoxysilane.

2. The water-based deicing coating according to claim 1, characterized in that: The triglyceride is glyceryl trioctanoate.

3. The aqueous de-icing coating according to claim 1, wherein: The silicone oil is benzyl silicone oil with a viscosity of 30 - 500 mPa·s.

4. The aqueous deicing coating according to claim 1, wherein: The medium-long chain alkyltrimethoxysilane is one of n-octyltrimethoxysilane, n-decyltrimethoxysilane, dodecyltrimethoxysilane, and hexadecyltrimethoxysilane.

5. The aqueous de-icing coating according to claim 1, characterized in that: The triglyceride / silicone oil plays a role in reducing the modulus of the coating, and the medium-long chain alkyltrimethoxysilane plays a role in hydrophobic modification of the coating surface and improving the dispersibility of the triglyceride / silicone oil in the coating.

6. The preparation method of an aqueous deicing coating according to claim 1, characterized in that: The method steps are as follows: (1) Add triglyceride / silicone oil and medium-long chain alkyltrimethoxysilane to the water-based polyurethane emulsion according to the mass ratio, place it on a vortex mixer, and mix at 2800 rpm for 5 min at room temperature to obtain a uniform and non-stratified mixture. (2) Cover the substrate with the mixture by scraping or spraying. (3) Cure the substrate covered with the mixture at the recommended curing temperature of the water-based polyurethane emulsion to obtain the coating.

7. The preparation method of an aqueous deicing coating according to claim 6, characterized in that: In step (1), the water-based polyurethane emulsion, triglyceride / silicone oil, and medium-long chain alkyltrimethoxysilane can be mechanically mixed into a non-stratified and uniform mixture without adding any surfactant.

8. The preparation method of an aqueous de-icing coating according to claim 6, characterized in that: The thickness of the coating obtained by curing in step (3) is 100 - 500 μm.

Images