Water-based aviation nano-composite coating for aircraft aluminum alloy skin

Abstract

The utility model belongs to the field of water-based composite coatings, and particularly relates to a water-based aviation nano-composite coating for an aircraft aluminum alloy skin. The coating sequentially comprises an anodized aluminum alloy base material, a water-based aviation nano-composite epoxy coating and a water-based high-weather-resistance aviation polyurethane coating from inside to outside. The water-based aircraft skin coating has base material universality, can be suitable for base materials such as aluminum alloy, titanium alloy, steel, stainless steel, composite materials and the like, and solves the problems that solvent-based aircraft coatings are high in VOC emission, and conventional water-based aircraft skin coatings are short in protective period and poor in comprehensive performance.

Description

Technical Field

[0001] The utility model belongs to a water-based composite coating, in particular to a water-based aviation nano-composite coating for aircraft aluminum alloy skin. Background Art

[0002] Aircraft skin and its supporting equipment coatings are an important component of aviation products. They play an important role in improving the corrosion resistance of aircraft aluminum alloys, stainless steel, steel, and composite materials. They are not only the external decorative materials of aircraft bodies, but also important materials for extending the service life of aircraft and ensuring flight safety. However, the amount of organic solvents emitted into the atmosphere during the manufacture of coatings is about 2% of the coating output, and the amount of organic solvents volatilized during the coating construction process is more than 50% of the coating volume. The organic solvents emitted during the production and application of coatings have become one of the main sources of air pollution. With the increasing global environmental protection policy requirements and social calls, reducing pollution and VOC emissions, using low-solvent, low-pollution, high-solid content coatings and water-based coatings have become important directions for the development of aviation coatings.

[0003] In the field of aviation manufacturing and maintenance, international coatings companies such as PPG Aerospace and AKZO NOBEL Aerospace have launched high-solid aviation coatings and water-based coatings. The application of water-based aviation coatings not only reduces the emission of toxic and hazardous substances and VOC emissions, but also promotes the development of aviation coatings towards green and water-based. However, the research and development of water-based aviation coatings in China started late, and there are currently few related products that can be used on a large scale. In addition, water-based aviation coatings are far behind solvent-based coatings in terms of weather resistance, chemical resistance, and environmental adaptability. Utility Model Content

[0004] In view of the problems in the prior art, the utility model provides a water-based aviation nano-composite coating for aircraft aluminum alloy skin and a preparation method thereof, which solves the problems of high VOC emissions of solvent-based aviation coatings, short protective period and poor comprehensive performance of conventional water-based aircraft skin coatings.

[0005] The technical solution of the utility model is:

[0006] A water-based aviation nano-composite coating for aircraft aluminum alloy skins comprises, from the inside to the outside, an anodized aluminum alloy substrate, a water-based aviation nano-composite epoxy coating and a water-based high-weather-resistant aviation polyurethane coating.

[0007] Furthermore, the above-mentioned aqueous aviation nano-composite coating for aircraft aluminum alloy skin is a POSS@SiO2 nano-silica-modified epoxy-phenyl cage-shaped silsesquioxane-modified graphene oxide nano-composite coating.

[0008] Furthermore, the above-mentioned aqueous aviation nano-composite coating for aircraft aluminum alloy skin, the aqueous high weather-resistant aviation polyurethane coating is an organic hybrid coating aqueous high weather-resistant aviation polyurethane coating of an interpenetrating network of silicone-modified polyisocyanate, fluorocarbon resin, and polyacrylic resin.

[0009] Furthermore, the above-mentioned aircraft aluminum alloy skin uses a water-based aviation nano-composite coating, the thickness of the water-based aviation nano-composite epoxy coating is 18-28 μm; the thickness of the water-based high weather-resistant aviation polyurethane coating is 45-55 μm.

[0010] The above-mentioned method for preparing a water-based aviation nanocomposite coating for aircraft aluminum alloy skin comprises the following steps:

[0011] S1: On an anodized aluminum alloy substrate, a water-based aviation nano-composite epoxy coating is applied to the substrate by air spraying, and a hard-dried water-based aviation nano-composite epoxy coating is obtained after natural drying for 8-12 hours;

[0012] S2: The hard-dried water-based aviation nano-composite epoxy coating surface is manually polished and roughened with sandpaper of 600-800 mesh, and then the surface is dusted;

[0013] S3: spraying the water-based high-weather-resistant aviation polyurethane coating on the polished and dust-removed surface of the water-based aviation nano-composite epoxy coating, and drying it naturally for 28-24 hours to obtain the water-based high-weather-resistant aviation polyurethane coating;

[0014] S4: Curing the coating obtained in step S4 at a temperature of 21-25° C. and a humidity of 73-77% for 7-10 days to obtain a water-based aviation nanocomposite coating.

[0015] Advantages and beneficial effects of the utility model:

[0016] (1) The water-based aviation nanocomposite coating for aircraft aluminum alloy skin in the utility model is a graphene oxide nanocomposite coating modified by POSS@SiO2 nano-silica modified epoxyphenyl cage silsesquioxane, which has a low water vapor permeability, excellent resistance to filiform corrosion and salt spray, and improves the long-term corrosion resistance of the water-based aviation composite coating;

[0017] (2) The water-based aviation nanocomposite coating for aircraft aluminum alloy skin in the utility model is an organic hybrid coating of an interpenetrating network of silicone-modified polyisocyanate, fluorocarbon resin, and polyacrylic resin, which has excellent flexibility, temperature shock resistance, and weather resistance, and improves the weather resistance and environmental adaptability of the water-based aviation composite coating;

[0018] (3) The water-based aviation nanocomposite coating for aircraft aluminum alloy skin in the utility model has low VOC content and excellent comprehensive performance. The combination of the two coatings improves the long-term anti-corrosion performance of the coating, which can meet the protection needs of aircraft skin and supporting equipment in harsh and complex environments such as coastal areas, offshore and islands and reefs;

[0019] (4) The utility model has the versatility of substrates and can be applied to substrates such as aluminum alloy, titanium alloy, steel, stainless steel, and composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of the water-based aviation nanocomposite coating for aircraft aluminum alloy skin of the utility model;

[0021] In the figure, 1-water-based aviation nano-composite epoxy coating; 2-water-based high weather-resistant aviation polyurethane coating; 3-anodized aluminum alloy substrate. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods. The following embodiments are used to illustrate the present invention but cannot be used to limit the scope of the present invention. Example

[0023] like Figure 1 As shown, a water-based aviation nano-composite coating for aircraft aluminum alloy skin includes, from the inside to the outside, an anodized aluminum alloy substrate 3, a water-based aviation nano-composite epoxy coating 1 and a water-based high-weather-resistant aviation polyurethane coating 2.

[0024] The water-based aviation nanocomposite epoxy coating 1 is a graphene oxide nanocomposite coating modified by POSS@SiO2 nano-silica-modified epoxyphenyl cage-shaped silsesquioxane, and the coating used in the coating is the coating disclosed in patent CN116790176A;

[0025] The water-based high-weather-resistant aviation polyurethane coating 2 is an organic hybrid water-based high-weather-resistant aviation polyurethane coating of an interpenetrating network of organosilicon-modified polyisocyanate, fluorocarbon resin, and polyacrylic resin. The coating is prepared from a water-based aviation polyurethane coating, which comprises component A and component B. Component A consists of a water-based hydroxy acrylate dispersion, a water-based fluorocarbon resin dispersion, a water-based auxiliary agent, a pigment, a matting powder, a mixed solvent, and deionized water; and component B consists of a polyisocyanate water-based curing agent, a silicone-modified polyisocyanate water-based curing agent, a solvent, and a dehydrating agent. The water-based hydroxy acrylate dispersion, water-based fluorocarbon resin dispersion, water-based auxiliary agent, pigment, filler, matting powder, solvent, polyisocyanate water-based curing agent, and dehydrating agent used in the coating component A and component B are all readily available conventional raw materials. The silicone-modified polyisocyanate water-based curing agent is a key raw material independently designed and synthesized. Its special structure gives the water-based aviation polyurethane coating good flexibility and wear resistance, and improves the coating's impact resistance, impact flexibility and low-temperature toughness; at the same time, the fluorosilicone-modified coating that it forms an organic interpenetrating network structure with fluorocarbon resin gives the coating long-term weather resistance and easy cleaning. Patent CN114605606A discloses a preparation method and application of a multi-cured anionic silicone-modified polyisocyanate water-based curing agent. The curing agent and water-based active hydrogen-containing resin are used to formulate a two-component water-based polyurethane coating. The formed coating film has better adhesion, weather resistance, high gloss, water resistance, solvent resistance and corrosion resistance than ordinary water-based polyurethane curing agents.

[0026] The method for preparing the above-mentioned aqueous aviation nanocomposite coating for aircraft aluminum alloy skin comprises the following steps:

[0027] S1: On an anodized aluminum alloy substrate, a water-based aviation nano-composite epoxy coating is applied on the anodized aluminum alloy substrate 3 by air spraying, and a hard-dried water-based aviation nano-composite epoxy coating 1 is obtained after natural drying for 8 hours, and the dry film thickness is 20 μm;

[0028] S2: The hard-dried water-based aviation nano-composite epoxy coating surface is manually polished and roughened with 600-grit sandpaper, and then the surface is dusted;

[0029] S3: spraying the water-based high weather-resistant aviation polyurethane coating on the polished and dust-removed surface of the water-based aviation nano-composite epoxy coating, and drying it naturally for 24 hours to obtain a water-based high weather-resistant aviation polyurethane coating 2 with a dry film thickness of 50 μm;

[0030] S4: Curing the coating obtained in step S4 at a temperature of 23° C. and a humidity of 75% for 7 days to obtain a water-based aviation nanocomposite coating.

[0031] The performance of the waterborne aviation nanocomposite coating was tested. The test substrate used was an anodized 2A12 aluminum alloy plate with a size of 0.5 mm × 70 mm × 150 mm. The test results are shown in Table 1. The test method and process are described as follows:

[0032] (1) Low temperature flexibility

[0033] The low temperature toughness of the water-based aviation nanocomposite coating for aircraft aluminum alloy skin prepared by the utility model is carried out in accordance with the provisions of GB / T 6742. The test environment temperature is (-51±3)°C, and the test is carried out using a type II bending tester, the cylindrical shaft diameter is 3mm, and a 10x magnifying glass is used for observation.

[0034] (2) Impact flexibility

[0035] The impact flexibility of the water-based aviation nanocomposite coating for aircraft aluminum alloy skin prepared by the utility model is tested according to the provisions of ASTM D6905. A 10-fold magnifying glass is used for observation, and the maximum elongation of the test coating without cracks is recorded.

[0036] (3) Temperature shock resistance

[0037] The temperature impact resistance of the water-based aviation nanocomposite coating for aircraft aluminum alloy skin prepared by the utility model is tested in accordance with the provisions of GJB150.5A. The low temperature test temperature is (-55±5)℃, and the holding time is 1h; the high temperature test temperature is (70±5)℃, and the holding time is 1h. The high and low temperature environment transition time is no more than 1 min, and one low temperature test and one high temperature test constitute one cycle.

[0038] (4) Impact resistance

[0039] The impact resistance of the water-based aviation nanocomposite coating for aircraft aluminum alloy skin prepared by the utility model is tested in accordance with the provisions of GB / T 1732. The maximum impact height without cracking and falling off is recorded.

[0040] (5) Water vapor transmission rate

[0041] The water vapor permeability of the water-based aviation nano-composite coating for aircraft aluminum alloy skin prepared by the utility model is carried out according to the provisions of ASTM F1249.

[0042] (6) Salt spray resistance

[0043] The salt spray resistance of the water-based aviation nano-composite coating for aircraft aluminum alloy skin prepared by the utility model is carried out according to the provisions of GB / T1771.

[0044] (7) Resistance to filiform corrosion

[0045] The filiform corrosion resistance of the water-based aviation nano-composite coating for aircraft aluminum alloy skin prepared by the utility model is carried out according to the provisions of GB / T 26323.

[0046] (8) The cleanability of the polyurethane coating prepared by the present invention was tested according to the method specified in 4.6.13 of the military standard MIL PRF 85285D, and the cleaning rate was calculated.

[0047] (9) Artificially accelerated aging

[0048] The artificial accelerated aging experiment of the water-based aviation nano-composite coating for aircraft aluminum alloy skin prepared by the utility model is carried out according to the provisions of GB / T 1865, 3000h, UVB-313, 4h drying, 4h condensation, and recording the test color difference and gloss loss rate.

[0049] The test results are shown in Table 1:

[0050] Table 1 Performance test results

[0051]

[0052] The above data show that the water-based aviation nano-composite coating for aircraft aluminum alloy skin of the utility model has low VOC content, excellent comprehensive performance, can significantly extend the protection period of the coating, and can meet the protection needs of aircraft skin and supporting equipment in harsh and complex environments such as coastal areas, seas, and islands and reefs.

Claims

1. A water-based aviation nanocomposite coating for aircraft aluminum alloy skin, characterized in that: From the inside to the outside, it includes anodized aluminum alloy substrate, water-based aviation nano-composite epoxy coating and water-based high weather-resistant aviation polyurethane coating.

2. The aqueous aviation nanocomposite coating for aircraft aluminum alloy skin according to claim 1, characterized in that: The thickness of the water-based aviation nano-composite epoxy coating is 18-28 μm; the thickness of the water-based high-weather-resistant aviation polyurethane coating is 45-55 μm.

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