Electrostatic spraying powder, high-pressure electrostatic spraying process of aluminum profile and corrosion-resistant aluminum profile

Abstract

The application relates to an electrostatic spraying powder, an aluminum profile high-pressure electrostatic spraying process and a corrosion-resistant aluminum profile. The electrostatic spraying powder contains the following raw materials according to weight parts: polyethylene acrylic acid 200-250 parts, barium sulfate 40-50 parts, monoalkoxy fatty acid titanium ester 5-10 parts, zinc powder 10-15 parts and modified nano silicon dioxide 12-15 parts; wherein the modified nano silicon dioxide is modified nano silicon dioxide modified by silane. After the aluminum profile is high-pressure electrostatically sprayed by the electrostatic spraying powder, the obtained product has a salt mist resistance time of more than 1500h, a contamination resistance index of less than or equal to 5.2, and has the advantages of high corrosion resistance and high contamination resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum profiles, and particularly relates to an electrostatic spraying powder, an aluminum profile high-voltage electrostatic spraying process and a corrosion-resistant aluminum profile. BACKGROUND

[0002] Aluminum profiles are widely used in aerospace, construction, solar new energy and other emerging fields due to excellent thermal ductility and easy processability. When the aluminum profiles subjected to heat treatment are placed in the air, a dense aluminum oxide film is formed on the surface, which has a certain corrosion resistance. However, the protective layer formed in the natural environment is too thin and has insufficient corrosion resistance, which cannot meet the corrosion resistance requirements of some aluminum alloys in long-term high-temperature and high-salinity areas. Therefore, the aluminum alloy needs to be surface treated to have high corrosion resistance.

[0003] Powder spraying is a commonly used surface treatment method for aluminum alloys. In terms of environmental protection, the government has increasingly strict regulations on the content of organic volatile matter (VOC) in the atmosphere, and high-voltage electrostatic powder spraying is the cleanest coating technology that can be achieved at present. The general process steps are: hanging-up - spraying - curing - unloading - packaging. The powder raw materials used are polyester resin, epoxy resin and the like.

[0004] For example, patent application CN117000564A discloses a new energy vehicle aluminum alloy frame powder spraying process, which comprises the following steps: preparing the following weight parts of raw materials: polyester resin 220-240 parts, glycerol epoxy resin 30-40 parts, anticorrosive filler 40-50 parts, additive 15-20 parts, curing agent 10-13 parts, and leveling agent 3-5 parts; the above-mentioned raw materials are added into a mixing machine in proportion, mixed, and extruded through a double-screw extruder to obtain a powder coating; the pretreated aluminum alloy frame is hung in a powder spraying chamber, the powder coating is uniformly sprayed onto the surface of the pretreated aluminum alloy frame through a spraying gun, and baking is performed to obtain the new energy vehicle aluminum alloy frame. The powder and process used in the patent can make the aluminum alloy frame have a certain corrosion resistance after treatment; however, benzene ester and DMF are used in the preparation of the additive, which has a serious impact on the environment in industrialization. Meanwhile, the process for preparing the spraying powder is complex and cumbersome, and requires a large cost in industrial use. SUMMARY

[0005] The present application aims to overcome the deficiencies of the prior art and provide an electrostatic spraying powder, an aluminum profile high-voltage electrostatic spraying process and a corrosion-resistant aluminum profile. Polyethylene acrylic acid powder is used as the main raw material, barium sulfate and zinc powder are used as fillers, and monoalkoxy fatty acid titanate and modified nano silicon dioxide are used to make the powder composition adhere to the surface of the aluminum profile by electrostatic spraying, thereby achieving excellent corrosion resistance and stain resistance.

[0006] Specifically as follows:

[0007] An electrostatic spraying powder comprises the following raw materials in parts by weight:

[0008] Polyethylene acrylic acid 200-250 parts, barium sulfate 40-50 parts, single-alkoxy fatty acid titanate 5-10 parts, zinc powder 10-15 parts, modified nano-silica 12-15 parts; wherein the modified nano-silica is modified by silane on nano-silica.

[0009] Further, it is composed of the following raw materials in parts by weight: polyethylene acrylic acid 200-250 parts, barium sulfate 40-50 parts, single-alkoxy fatty acid titanate 5-10 parts, zinc powder 10-15 parts, modified nano-silica 12-15 parts;

[0010] Preferably, it is composed of the following raw materials in parts by weight: polyethylene acrylic acid 210-240 parts, barium sulfate 40-50 parts, single-alkoxy fatty acid titanate 5-10 parts, zinc powder 10-15 parts, modified nano-silica 12-15 parts; or, polyethylene acrylic acid 210-240 parts, barium sulfate 42-48 parts, single-alkoxy fatty acid titanate 5-10 parts, zinc powder 10-15 parts, modified nano-silica 12-15 parts; or,

[0011] Polyethylene acrylic acid 210-240 parts, barium sulfate 42-48 parts, single-alkoxy fatty acid titanate 5-10 parts, zinc powder 12-14 parts, modified nano-silica 12-15 parts; or,

[0012] Polyethylene acrylic acid 210-240 parts, barium sulfate 42-48 parts, single-alkoxy fatty acid titanate 5-10 parts, zinc powder 12-14 parts, modified nano-silica 13-14 parts; or,

[0013] Polyethylene acrylic acid 210-250 parts, barium sulfate 43-48 parts, single-alkoxy fatty acid titanate 6-9 parts, zinc powder 12-13 parts, modified nano-silica 13-14 parts.

[0014] Further, the polyethylene acrylic acid is a solid powder, and the preparation method comprises the following steps:

[0015] Step one: 50-60 parts of polyethylene wax is added to 40-50 parts of butyl acetate, stirred and dissolved, and then 0.1-0.2 parts of initiator is added;

[0016] Step two: 10 parts of acrylic acid monomer is dropped into the reaction system of step one, the solution begins to turn white, and after dropping is completed, 0.1-0.2 parts of initiator is added to produce white precipitate;

[0017] Step three: filtering the reaction system of step two, drying the white precipitate to obtain polyethylene acrylic acid powder.

[0018] Further, the molecular weight of the polyethylene wax is 800-1000;

[0019] Optionally, the initiator is any one of potassium persulfate or ammonium persulfate;

[0020] Optionally, 10 parts of acrylic monomer is slowly dropped in 14-16 minutes;

[0021] Optionally, the grafting rate of acrylic acid in the polyethylene acrylic acid is 18-22%.

[0022] Further, the preparation method of the modified nano-silicon dioxide comprises: dissolving nano-silicon dioxide in a solvent, ultrasonic dispersion to obtain a suspension, adding γ-aminopropyl triethoxysilane, ultrasonic mixing, then constant temperature reaction, then centrifugation, vacuum drying the white powder obtained, which is the modified nano-silicon dioxide.

[0023] Further, the mass ratio of the nano-silicon dioxide and γ-aminopropyl triethoxysilane is (8-12):(1-3);

[0024] Optionally, the solvent is any one of ethanol, propanol, butanol, acetone;

[0025] Optionally, the temperature of the constant temperature reaction is 50-100℃, and the reaction time is 1-5h.

[0026] The application also protects an aluminum profile high-voltage electrostatic spraying process, which comprises the following steps: after surface pretreatment of the aluminum profile, the electrostatic spraying powder is sprayed, then solidified and cooled.

[0027] Further, the spraying is to uniformly spray the electrostatic spraying powder to the surface of the pretreated aluminum profile through a spraying gun, the distance between the spraying gun and the pretreated aluminum profile is controlled to be 200-300mm, the voltage is 50-100kV, the current is 50-100μA, the total air volume is 1.8-8m 3 / h, the electrode cleaning air volume is set to be 0.1-2.5m 3 / h, the up-down moving speed of the spraying gun is 290-330mm / s, and the environmental temperature is controlled to be 30-40℃.

[0028] Preferably, the solidification temperature is 180-220℃, and the solidification time is 15-40min.

[0029] The application also protects the corrosion-resistant aluminum profile prepared by the high-voltage electrostatic spraying process of the aluminum profile, and the salt mist resistance time of the corrosion-resistant aluminum profile is greater than or equal to 1500h, and the salt mist resistance refers to the resistance to a test temperature of 35±2℃ and a neutral condition salt mist concentration of 5±1wt%.

[0030] Further, the contamination resistance index of the corrosion-resistant aluminum profile is less than or equal to 5.2.

[0031] Beneficial effects: In the application, the polyethylene acrylic acid has active sites of alkenyl and hydroxyl groups, can be combined with fillers to form a stable coating, and after electrostatic spraying and curing, can play a good corrosion resistance and contamination resistance advantage.

[0032] Further, the application uses modified nano-silicon dioxide as a curing agent to cure the powder coating, and on this basis, uses a monoalkoxy fatty acid titanate to further improve the adhesion, so that the corrosion resistance of the electrostatically sprayed aluminum profile is further improved. DETAILED DESCRIPTION

[0033] The definitions of some terms used in the application are given below, and the definitions and meanings of other terms not mentioned are known in the art:

[0034] Aluminum profile, in the application, refers to an aluminum-containing product, including aluminum materials, and also including aluminum alloys, and the shape of the material is not limited, and can have a flat surface or a special-shaped structure, for example, a surface with a certain curvature or a hole.

[0035] The preferred embodiments of the application will be described in more detail below. Although the preferred embodiments of the application are described below, it should be understood that the application can be implemented in various forms and should not be limited by the embodiments described herein. If a specific technique or condition is not specified in the examples, it is performed according to the technique or condition described in the literature in the art or according to the product instructions. If the manufacturer of the reagent or instrument is not specified, it is a conventional product that can be obtained by purchase. In the following examples, unless otherwise specified, "%" refers to the percentage by weight.

[0036] The test methods used below include:

[0037] The measurement method of the grafting rate of acrylic acid is as follows: polyethylene acrylic acid powder is extracted with acetone for 20-24h, 0.5g is dissolved in hot xylene, then neutralized with sodium hydroxide-ethanol solution, phenothalin is used as an indicator, and the excess alkali is titrated with hydrochloric acid. Finally, the grafting rate is measured.

[0038] The calculation formula of the grafting rate is as follows:

[0039] (mol amount of sodium hydroxide-mol amount of hydrochloric acid)*70.06 / 0.5*100%

[0040] Salt fog resistance test: Referring to GB / T 10125-2012, neutral salt spray test is adopted.

[0041] Stain resistance test: Referring to the test method for stain resistance of exterior wall coating in national standard GB / T9780-2013 "Test method for stain resistance of coating on building"; Specifically, fly ash is stirred uniformly to make a suspension liquid with a water / fly ash mass ratio of 0.9:1 for standby; The initial reflectance of the coating is measured at the upper, middle and lower positions of the sample coating, and their average value A is taken; The suspension liquid is evenly brushed on the surface of the coating with a wolf hair brush first horizontally and then vertically, and the brushing amount of the suspension liquid is (0.7±0.1) g; Place for two hours under standard test conditions; Wash in the washing device and place for 24 h, and repeat the cycle for 5 times; Measure the reflectance at the upper, middle and lower positions of the coating, and take their average value B; The stain resistance of the coating is calculated according to the following formula:

[0042] X = (A-B) / A x 100

[0043] The main reagents used below include:

[0044] Monoalkoxy fatty acid titanate, model: KR-TTS, manufacturer: Kenrich Petroleum Corporation, USA.

[0045] Test group one

[0046] Add 50 parts of polyethylene wax with a molecular weight of 800-1000 to 40 parts of butyl acetate, stir and dissolve, and then add 0.1 part of initiator (the initiator is potassium persulfate, the same below); Then slowly drop 10 parts of acrylic monomer into the solution for 15 minutes, the solution begins to turn white, and after dropping, add 0.1 part of initiator; At this time, the white precipitate in the solution is polyethylene acrylic acid; Filter out the supernatant of the solution, and vacuum dry the white precipitate at the bottom to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0047] Test group two

[0048] Add 55 parts of polyethylene wax with a molecular weight of 800-1000 to 45 parts of butyl acetate, stir and dissolve, and then add 0.15 parts of initiator; Then slowly drop 10 parts of acrylic monomer into the solution for 15 minutes, the solution begins to turn white, and after dropping, add 0.15 parts of initiator; At this time, the white precipitate in the solution is polyethylene acrylic acid; Filter out the supernatant of the solution, and vacuum dry the white precipitate at the bottom to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0049] Test group three

[0050] Add 60 parts of polyethylene wax with molecular weight of 800-1000 into 50 parts of butyl acetate, stir and dissolve, then add 0.2 parts of initiator; then slowly drop 10 parts of acrylic monomer in 15 minutes, the solution begins to turn white, after dropping, add 0.2 parts of initiator; at this time, the white precipitate in the solution is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the white precipitate to obtain polyethylene acrylic acid powder.

[0051] Test group four

[0052] Add 55 parts of polyethylene wax with molecular weight of 800-1000 into 45 parts of butyl acetate, stir and dissolve, then add 0.15 parts of initiator; then slowly drop 10 parts of acrylic monomer in 15 minutes, the solution begins to turn white, after dropping, add 0.15 parts of initiator; at this time, the white precipitate in the solution is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the white precipitate to obtain polyethylene acrylic acid powder.

[0053] Test group five

[0054] Add 55 parts of polyethylene wax with molecular weight of 800-1000 into 45 parts of butyl acetate, stir and dissolve, then add 0.15 parts of initiator; then slowly drop 10 parts of acrylic monomer in 15 minutes, the solution begins to turn white, after dropping, add 0.15 parts of initiator; at this time, the white precipitate in the solution is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the white precipitate to obtain polyethylene acrylic acid powder.

[0055] Comparison group one

[0056] Add 55 parts of polyethylene wax with molecular weight of 1000-8000 into 45 parts of butyl acetate, stir and dissolve, then add 0.15 parts of initiator; then slowly drop 10 parts of acrylic monomer in 15 minutes, the solution begins to turn white, after dropping, add 0.15 parts of initiator; at this time, the white precipitate in the solution is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the white precipitate to obtain polyethylene acrylic acid powder.

[0057] Comparison group two

[0058] Add 40 parts of polyethylene wax with molecular weight of 800-1000 into 45 parts of butyl acetate, stir and dissolve, then add 0.15 parts of initiator; then slowly drop 10 parts of acrylic monomer in 15 minutes, the solution begins to turn white, after dropping, add 0.15 parts of initiator; at this time, the white precipitate in the solution is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the white precipitate to obtain polyethylene acrylic acid powder.

[0059] Comparative Group Three

[0060] Add 55 parts of polyethylene wax with molecular weight of 800-1000 into 35 parts of butyl acetate, stir and dissolve, then add 0.15 parts of initiator; then slowly drop 10 parts of acrylic monomer in 15 minutes, the solution begins to turn white, after dropping, add 0.15 parts of initiator; at this time, the white precipitate in the solution is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the white precipitate to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0061] Comparative Group Four

[0062] Add 55 parts of polyethylene wax with molecular weight of 800-1000 into 45 parts of petroleum ether, stir and dissolve, then add 0.15 parts of initiator; then slowly drop 10 parts of acrylic monomer in 15 minutes, the solution begins to turn white, after dropping, add 0.15 parts of initiator; at this time, the white precipitate in the solution is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the white precipitate to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0063] Comparative Group Five

[0064] Add 55 parts of polyethylene wax with molecular weight of 800-1000 into 45 parts of butyl acetate, stir and dissolve, then add 0.15 parts of initiator; then quickly drop 10 parts of acrylic monomer in 7-8 minutes, the solution begins to turn white, after dropping, add 0.15 parts of initiator; but the speed of acrylic acid is too fast to form a white waxy solid, and the reaction cannot continue.

[0065] Table 1 Composition comparison and experimental phenomena of each test group and comparative group

[0066]

[0067]

[0068] According to the experimental results in Table 1, it can be seen that:

[0069] 1. Compared with Comparative Groups One to Three and Test Group Five, it can be seen that the grafting rate of acrylic acid is greatly increased by using low molecular weight polyethylene wax for grafting reaction with acrylic acid. The polyethylene acrylic acid generated by using high molecular weight polyethylene wax is not soluble in water, which limits its use in the environment; and if the amount of polyethylene wax used is too small, excess polyacrylic acid impurities will be generated, which will form a mixture powder with polyethylene acrylic acid, resulting in that the mixture powder is not soluble in water, which limits its use in the environment.

[0070] 2、Comparative Group Four and five test groups compared can be seen, grafting reaction process using butyl acetate as solvent grafting reaction, solvent safe non-toxic, overcome the original petroleum ether flammable explosive shortcomings, and improve the grafting rate of acrylic acid.

[0071] 3、Comparative Group Five and five test groups compared can be seen, acrylic monomer should not be added too fast, otherwise it will be clumping, generating white waxy solid, resulting in the reaction can not be carried out.

[0072] Example 1

[0073] The polyethylene acrylic powder prepared in Test Group One was used to prepare an electrostatic spray powder.

[0074] First, the modified nano-silica was obtained by the following process: 10 g of nano-silica was dissolved in 60 ml of ethanol, and ultrasonic dispersion was performed for 30 minutes to obtain a uniform suspension. Then, 3 g of KH550 γ-aminopropyl triethoxysilane was added to the suspension, and ultrasonic mixing was performed for 5 minutes, followed by constant temperature reaction for 2 hours. Then, centrifugation was performed, followed by ultrasonic centrifugation. The white powder obtained was vacuum dried to obtain the modified nano-silica.

[0075] Then, the raw materials were mixed according to the amounts in Table 2 to obtain the electrostatic spray powder.

[0076] The prepared electrostatic spray powder was used for electrostatic spraying of aluminum alloy profiles, including: surface pretreatment of the aluminum alloy profiles, including water washing, alkali washing, water washing, neutralization and water washing, wherein the alkali washing was performed using a NaOH aqueous solution with a concentration of 60 g / L for 1 min; the neutralization was performed using a sulfuric acid aqueous solution with a concentration of 60 g / L for 2 min.

[0077] The pretreated aluminum alloy profiles were hung in the powder spraying chamber, and the electrostatic spray powder was uniformly sprayed onto the surface of the pretreated aluminum alloy profiles by a spraying gun. The distance between the spraying gun and the pretreated aluminum alloy profiles was controlled to be 200 mm, the voltage was 50 kV, the current was 50 μA, the total air volume was 3 m 3 / h, the electrode cleaning air volume was set to 1 m 3 / h, the up and down movement speed of the spraying gun was set to 290 mm / s, and the environmental temperature was controlled at 30-35°C. After spraying, heating and curing were performed, the curing temperature was set to 180°C, the curing time was 40 min, and the temperature was cooled to room temperature to obtain the corrosion-resistant aluminum profiles. Performance tests were performed, and the test results are shown in Table 3.

[0078] Table 2 Raw material dosage Table / weight parts

[0079] Raw materials Example 1 Example 2 Example 3 Example 4 Example 5 Polyethylene acrylic acid 200 220 250 210 240 Barium sulfate 50 40 43 48 45 Monoalkoxy fatty acid titanate 5 8 6 9 10 Zinc powder 12 14 13 13 11 Modified nanosilica 12 12 13 14 15

[0080] Example 2

[0081] The polyethylene acrylic acid powder prepared in the first test group is used to prepare the electrostatic spraying powder.

[0082] First, the modified nano-silica is obtained by the following process: 8 g of nano-silica is dissolved in 60 ml of ethanol, and ultrasonic dispersion is performed for 30 minutes by an ultrasonic cleaning instrument to obtain a uniform suspension. 3 g of KH550 γ-aminopropyl triethoxysilane is added to the suspension, and ultrasonic mixing is performed for 5 minutes, followed by constant temperature reaction for 2 hours. Then, centrifugation is performed, and the obtained white powder is vacuum dried to obtain the modified nano-silica.

[0083] Then, the raw materials are uniformly mixed according to the amounts in Table 2 to obtain the electrostatic spraying powder.

[0084] The prepared electrostatic spraying powder is used for electrostatic spraying of the aluminum alloy profile, including: surface pretreatment of the aluminum alloy profile, including water washing, alkali washing, water washing, neutralization and water washing, wherein the alkali washing is performed by using a NaOH aqueous solution with a concentration of 60 g / L for 1 minute; the neutralization is performed by using a sulfuric acid aqueous solution with a concentration of 60 g / L for 2 minutes.

[0085] The pretreated aluminum alloy profile is hung in the powder spraying chamber, and the electrostatic spraying powder is uniformly sprayed onto the surface of the pretreated aluminum alloy profile by a spraying gun. The distance between the spraying gun and the pretreated aluminum alloy profile is controlled to be 300 mm, the voltage is 100 kV, the current is 100 μA, the total air volume is 5 m 3 / h, the electrode cleaning air volume is set to 1.5 m 3 / h, the up and down movement speed of the spraying gun is set to 300 mm / s, and the environmental temperature is controlled to be 30-40℃. After spraying, heating and curing are performed. The curing temperature is set to be 220℃, the curing time is 15 minutes, and the temperature is cooled to room temperature to obtain the corrosion-resistant aluminum profile. Performance testing is performed, and the test results are shown in Table 3.

[0086] Example 3

[0087] The polyethylene acrylic acid powder prepared in the first test group is used to prepare the electrostatic spraying powder.

[0088] First, the modified nano-silica is obtained by the following process: 8 g of nano-silica is dissolved in 60 ml of ethanol, and ultrasonic dispersion is performed for 30 minutes by an ultrasonic cleaning instrument to obtain a uniform suspension. 3 g of KH550 γ-aminopropyl triethoxysilane is added to the suspension, and ultrasonic mixing is performed for 5 minutes, followed by constant temperature reaction for 2 hours. Then, centrifugation is performed, and the obtained white powder is vacuum dried to obtain the modified nano-silica.

[0089] Then, the raw materials are uniformly mixed according to the amounts in Table 2 to obtain the electrostatic spraying powder.

[0090] The prepared electrostatic spraying powder is used for electrostatic spraying of the aluminum alloy profile, including: surface pretreatment of the aluminum alloy profile, including water washing, alkali washing, water washing, neutralization and water washing, wherein the alkali washing is carried out by using a NaOH aqueous solution with a concentration of 60 g / L for cleaning for 1 min; the neutralization is carried out by using a sulfuric acid aqueous solution with a concentration of 60 g / L for cleaning for 2 min.

[0091] The pretreated aluminum alloy profile is hung in the powder spraying chamber, and the electrostatic spraying powder is uniformly sprayed onto the surface of the pretreated aluminum alloy profile by the spraying gun, the distance between the spraying gun and the pretreated aluminum alloy profile is controlled to be 220 mm, the voltage is 80 kV, the current is 80 μA, the total air volume is 4 m 3 / h, the electrode cleaning air volume is set to 2 m 3 / h, the up-down moving speed of the spraying gun is set to 310 mm / s, and the environmental temperature is controlled to be 30-40℃. After spraying, heating and curing are carried out, the curing temperature is set to 210℃, the curing time is 20 min, and the temperature is cooled to room temperature to obtain the corrosion-resistant aluminum profile, and performance test is carried out, and the test results are shown in Table 3.

[0092] Example 4

[0093] The polyethylene acrylic acid powder prepared in the first test group is used to prepare the electrostatic spraying powder.

[0094] Firstly, the modified nano-silicon dioxide is obtained, and the preparation process is as follows: 10 g of nano-silicon dioxide is dissolved in 60 ml of ethanol, and ultrasonic dispersion is carried out for 30 minutes by using an ultrasonic cleaning instrument to obtain a uniform suspension, 2 g of KH550 γ-aminopropyl triethoxysilane is added to the suspension, ultrasonic mixing is carried out for 5 minutes, and then constant temperature reaction is carried out for 2 hours, and then centrifugation is carried out, and then ultrasonic centrifugation is carried out, and then the obtained white powder is vacuum dried to obtain the modified nano-silicon dioxide.

[0095] Then, the raw materials are uniformly mixed according to the amount in Table 2 to obtain the electrostatic spraying powder.

[0096] The prepared electrostatic spraying powder is used for electrostatic spraying of the aluminum alloy profile, including: surface pretreatment of the aluminum alloy profile, including water washing, alkali washing, water washing, neutralization and water washing, wherein the alkali washing is carried out by using a NaOH aqueous solution with a concentration of 60 g / L for cleaning for 1 min; the neutralization is carried out by using a sulfuric acid aqueous solution with a concentration of 60 g / L for cleaning for 2 min.

[0097] The pretreated aluminum alloy profile is hung in the powder spraying chamber, and the electrostatic spraying powder is uniformly sprayed onto the surface of the pretreated aluminum alloy profile by the spraying gun, the distance between the spraying gun and the pretreated aluminum alloy profile is controlled to be 220 mm, the voltage is 80 kV, the current is 80 μA, the total air volume is 4 m 3 / h, the electrode cleaning air volume is set to 2 m 3 / h, the up-and-down moving speed of the spray gun is set as 320 mm / s, and the ambient temperature is controlled at 30-40℃. After spraying, heating and curing are carried out, the curing temperature is set as 215℃, the curing time is 20 min, and the temperature is cooled to room temperature to obtain the corrosion-resistant aluminum profile, and performance test is carried out, and the test results are shown in Table 3.

[0098] Example 5

[0099] The polyethylene acrylic acid powder prepared in Test Group One is used to prepare the electrostatic spraying powder.

[0100] Firstly, the modified nano-silica is obtained, and the preparation process is as follows: 9 g of nano-silica is dissolved in 60 ml of ethanol, and ultrasonic dispersion is carried out for 30 minutes to obtain a uniform suspension. 3 g of KH550 γ-aminopropyl triethoxysilane is added to the suspension, ultrasonic mixing is carried out for 5 minutes, and then constant temperature reaction is carried out for 2 hours. Then, centrifugation is carried out, and then ultrasonic centrifugation is carried out. The white powder obtained is vacuum dried to obtain the modified nano-silica.

[0101] Then, according to the amount in Table 2, the raw materials are uniformly mixed to obtain the electrostatic spraying powder.

[0102] The prepared electrostatic spraying powder is used for electrostatic spraying of the aluminum alloy profile, including: the aluminum alloy profile is subjected to surface pretreatment, including water washing, alkali washing, water washing, neutralization and water washing, wherein the alkali washing is carried out by using NaOH aqueous solution with a concentration of 60 g / L for 1 min; the neutralization is carried out by using sulfuric acid aqueous solution with a concentration of 60 g / L for 2 min.

[0103] The pretreated aluminum alloy profile is hung in the powder spraying chamber, and the electrostatic spraying powder is uniformly sprayed onto the surface of the pretreated aluminum alloy profile by using the spraying gun. The distance between the spraying gun and the pretreated aluminum alloy profile is controlled to be 260 mm, the voltage is 80 kV, the current is 80 μA, the total air volume is 4 m 3 / h, the air volume of the electrode cleaning is set as 1 m 3 / h, the up-and-down moving speed of the spray gun is set as 300 mm / s, and the ambient temperature is controlled at 30-40℃. After spraying, heating and curing are carried out, the curing temperature is set as 215℃, the curing time is 20 min, and the temperature is cooled to room temperature to obtain the corrosion-resistant aluminum profile, and performance test is carried out, and the test results are shown in Table 3.

[0104] Comparative Example 1

[0105] Referring to Example 1, the difference lies in that equal mass of commercially available polyethylene acrylic acid (acrylic acid grafting rate is 15%) is used instead of the polyethylene acrylic acid powder prepared in Test Group One.

[0106] Comparative Example 2

[0107] Reference to Example 1, except that equal mass of titanate coupling agent LICA38 (CAS: 103432-54-8) was used instead of monoalkoxy fatty acid titanate.

[0108] Comparative Example 3

[0109] Reference to Example 1, except that equal mass of nano-silica was used instead of modified nano-silica.

[0110] Comparative Example 4

[0111] Reference to Example 1, except that the amount of polyethylene acrylic acid was 180 parts.

[0112] Comparative Example 5

[0113] Reference to Example 1, except that the polyethylene acrylic acid was the polyethylene acrylic acid powder prepared in Comparative Group 1. The prepared electrostatic spraying powder was electrostatically sprayed on the aluminum alloy profile, and the method was the same as in Example 1. It was found that the paint was difficult to solidify and form in the predetermined time.

[0114] Comparative Example 6

[0115] Reference to Example 1, except that the polyethylene acrylic acid was the polyethylene acrylic acid powder prepared in Comparative Group 2. The prepared electrostatic spraying powder was electrostatically sprayed on the aluminum alloy profile, and the method was the same as in Example 1. It was found that the paint was difficult to solidify and form in the predetermined time.

[0116] Table 3: Test results of the properties of the corrosion-resistant aluminum profile

[0117]

[0118]

[0119] From the results in Table 3, it can be found that in Comparative Example 1, the polyethylene acrylic acid with a low grafting rate was used, and after being sprayed on the surface of the aluminum profile, the solidification speed on the surface of the aluminum profile was slow, the solidification degree was low, and the powder surface layer formed had low salt mist resistance and stain resistance; in Comparative Example 2, the titanate coupling agent LICA38 was used, and after using the coupling agent, the adhesion of the raw material to the surface of the aluminum profile was weak, the adhesion of the raw material was weak, resulting in low salt mist resistance and stain resistance; in Comparative Example 3, the nano-silica was not modified, and it was difficult to solidify; in Comparative Example 4, the content of polyethylene acrylic acid in the electrostatic powder coating was low, resulting in a large proportion of other materials, and the performance of the main components was not fully utilized, resulting in weak salt mist resistance and stain resistance.

[0120] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details of the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0121] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again by the present application.

[0122] In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the idea of the present application, and it should also be considered as disclosed by the present application.

Claims

1. An electrostatically sprayable powder, characterized in that: According to parts by weight comprising the following raw materials: Polyethylene acrylic acid 200-250 parts, barium sulfate 40-50 parts, single alkoxy fatty acid titanate 5-10 parts, zinc powder 10-15 parts, modified nano-silicon dioxide 12-15 parts; wherein the modified nano-silicon dioxide is modified by silane on nano-silicon dioxide, and the preparation method of the modified nano-silicon dioxide comprises: dissolving nano-silicon dioxide in a solvent, ultrasonic dispersion to obtain a suspension, adding γ-aminopropyl triethoxysilane, and the mass ratio of the nano-silicon dioxide and the γ-aminopropyl triethoxysilane is (8-12):(1-3); after ultrasonic mixing, constant temperature reaction, centrifugation, vacuum drying of the obtained white powder, the modified nano-silicon dioxide is obtained; The grafting rate of acrylic acid in the polyethylene acrylic acid is 18-22%.

2. The electrostatically sprayable powder of claim 1, wherein: According to parts by weight consisting of the following raw materials: polyethylene acrylic acid 200-250 parts, barium sulfate 40-50 parts, single alkoxy fatty acid titanate 5-10 parts, zinc powder 10-15 parts, modified nano-silicon dioxide 12-15 parts.

3. The electrostatically sprayable powder of claim 2, wherein: According to parts by weight consisting of the following raw materials: polyethylene acrylic acid 210-240 parts, barium sulfate 40-50 parts, single alkoxy fatty acid titanate 5-10 parts, zinc powder 10-15 parts, modified nano-silicon dioxide 12-15 parts.

4. The electrostatically sprayable powder of claim 2, wherein: According to parts by weight consisting of the following raw materials: polyethylene acrylic acid 210-240 parts, barium sulfate 42-48 parts, single alkoxy fatty acid titanate 5-10 parts, zinc powder 10-15 parts, modified nano-silicon dioxide 12-15 parts.

5. The electrostatically sprayable powder of claim 2, wherein: According to parts by weight consisting of the following raw materials: polyethylene acrylic acid 210-240 parts, barium sulfate 42-48 parts, single alkoxy fatty acid titanate 5-10 parts, zinc powder 12-14 parts, modified nano-silicon dioxide 12-15 parts.

6. The electrostatically sprayable powder of claim 2, wherein: According to parts by weight consisting of the following raw materials: polyethylene acrylic acid 210-240 parts, barium sulfate 42-48 parts, single alkoxy fatty acid titanate 5-10 parts, zinc powder 12-14 parts, modified nano-silicon dioxide 13-14 parts.

7. The electrostatically sprayable powder of claim 2, wherein: According to parts by weight consisting of the following raw materials: polyethylene acrylic acid 210-250 parts, barium sulfate 43-48 parts, single alkoxy fatty acid titanate 6-9 parts, zinc powder 12-13 parts, modified nano-silicon dioxide 13-14 parts.

8. The electrostatically sprayable powder of claim 1, wherein: The polyethylene acrylic acid is a solid powder, and the preparation method comprises the following steps: Step one: 50-60 parts of polyethylene wax is added to 40-50 parts of butyl acetate, stirred and dissolved, and then 0.1-0.2 parts of initiator is added; Step two: 10 parts of acrylic acid monomer is dropped into the reaction system of step one, the solution begins to turn white, and after dropping, 0.1-0.2 parts of initiator is added, and white precipitate is generated; Step three: the reaction system of step two is filtered, and the obtained white precipitate is dried to obtain polyethylene acrylic acid powder.

9. The electrostatically sprayable powder of claim 8, wherein: The molecular weight of the polyethylene wax is 800-1000; the initiator is any one of potassium persulfate or ammonium persulfate; 10 parts of acrylic acid monomer is slowly dropped in 14-16 minutes.

10. The electrostatically sprayable powder of claim 1, wherein: The solvent is any one of ethanol, propanol, butanol, and acetone.

11. The electrostatically sprayable powder of claim 10, wherein: The temperature of the constant temperature reaction is 50-100 DEG C, and the reaction time is 1-5 hours.

12. A high voltage electrostatic spray process for anodized aluminum profiles, characterized in that: After surface pretreatment of the aluminum profile, the electrostatic spray powder of any one of claims 1-11 is used for spraying, and then solidification and cooling.

13. The high-voltage electrostatic spraying process for aluminum profiles according to claim 12, characterized in that: The spraying is to spray the electrostatic spraying powder to the pretreated aluminum profile surface through a spraying gun, the distance between the spraying gun and the pretreated aluminum profile is controlled to be 200-300 mm, the voltage is 50-100 kV, the current is 50-100 μA, the total gas volume is 1.8-8 m 3 / h, the electrode cleaning air volume is set to be 0.1-2.5 m 3 / h, the up and down moving speed of the spraying gun is 290-330 mm / s, and the environmental temperature is controlled to be 30-40℃.

14. The high-voltage electrostatic spraying process for aluminum profiles according to claim 13, characterized in that: The solidification temperature is 180-220 DEG C, and the solidification time is 15-40 minutes.

15. The corrosion resistant aluminum profile prepared by the process of high- voltage electrostatic spraying of aluminum profile according to any one of claims 12-14, characterized by: The corrosion-resistant aluminum profile has a salt mist resistance of greater than or equal to 1500 hours, and the salt mist resistance refers to resistance to a test temperature of 35±2 DEG C and a neutral condition salt mist concentration of 5±1 wt%.

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