Bright corrosion-resistant aluminum profile and preparation method thereof

Abstract

The invention discloses a preparation method of a bright corrosion-resistant aluminum profile, and relates to the technical field of aluminum profile processing, and the preparation method comprises the following steps: mixing and smelting raw materials, pouring, and homogenizing to form a cast ingot; extruding and performing heat treatment to form an aluminum profile; and carrying out surface treatment to obtain the bright corrosion-resistant aluminum profile. The surface treatment comprises electrolytic oxidation, electrophoretic painting and hole sealing. The rare earth elements play roles in purifying a matrix, refining and modifying and microalloying in the aluminum alloy, the aluminum alloy structure is refined, better compactness and integrity can be shown after oxidation, the protection performance of the aluminum profile is improved, and the corrosion resistance and brightness of the aluminum profile are improved. The aluminum profile is pretreated through anode plasma electrolytic oxidation, and the surface of the aluminum profile is oxidized; and cathode plasma electrolytic deposition is utilized, so that direct contact between the cathode aluminum profile and electrolyte is avoided, pores of the barrier layer are sealed, a more compact oxide layer is obtained, and the brightness and the corrosion resistance are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum profile processing, and specifically relates to a bright and corrosion-resistant aluminum profile and a preparation method thereof. Background Art

[0002] Aluminum and its alloys have many advantages and are widely used in fields such as machinery manufacturing, architectural decoration, aerospace, and electrical and electronics. Methods such as electroplating, electroless plating, anodic oxidation, and vapor deposition can improve the surface hardness, wear resistance, corrosion resistance, etc. of aluminum and its alloys. Micro-arc oxidation can form an oxide layer on the surface of aluminum and its alloys. Compared with other technologies, the growth rate of the oxide layer is higher, the bonding force with the aluminum alloy matrix is stronger, and it has better wear resistance and corrosion resistance. However, micro-arc oxidation is an anodic reaction, and anodic dissolution and the generation of a passivation film will occur, resulting in a porous surface of the oxide layer, which affects the corrosion resistance and surface brightness of the aluminum profile. Therefore, we propose a bright and corrosion-resistant aluminum profile and a preparation method thereof. Summary of the Invention

[0003] The purpose of the present invention is to provide a bright and corrosion-resistant aluminum profile and a preparation method thereof to solve the problems raised in the above background art.

[0004] To solve the above technical problems, the present invention provides the following technical solution: A preparation method of a bright and corrosion-resistant aluminum profile, including the following processes:

[0005] Mix and melt the raw materials, cast, and perform homogenization treatment to form an ingot;

[0006] Extrude and perform heat treatment to form an aluminum profile;

[0007] Perform surface treatment to obtain a bright and corrosion-resistant aluminum profile.

[0008] Further, the aluminum profile includes the following components: by mass, Si (silicon): 0.2% - 0.6%, Mg (magnesium): 0.35% - 0.90%, Fe (iron): ≤0.05%, Cu (copper): ≤0.10%, Mn (manganese): ≤0.10%, Cr (chromium): ≤0.10%, Ti (titanium): ≤0.10%, Zn (zinc): ≤0.10%, RE (rare earth element): 0.1% - 0.4%, and the balance is Al (aluminum).

[0009] Further, RE (rare earth element) is one or a mixture of more of Y (yttrium), Ce (cerium), and La (lanthanum).

[0010] Further, the process conditions for homogenization treatment are as follows: heating to 520 - 530 °C, holding for 1.0 - 1.5 h; heating up to 530 - 550 °C, holding for 6.5 - 8.0 h; placing in a cooling furnace and cooling to below 100 °C, taking out, and air-cooling to room temperature.

[0011] Further, the process conditions for the extrusion are as follows: preheating the ingot to 455 - 465 °C, heating the die to 450 - 460 °C, extrusion ratio of 12 - 17, extrusion speed of 2.5 - 4.0 m / min; air-cooling to room temperature.

[0012] Further, the heat treatment includes solution treatment and aging.

[0013] The solution treatment process is: holding at 500 - 550 °C for 6 - 8 h, and quenching in water at 25 - 40 °C.

[0014] The aging process is: heating temperature of 160 - 180 °C, holding time of 4 - 6 h; air-cooling to room temperature.

[0015] In the above technical solution, adding rare earth elements to the aluminum alloy can play the roles of purifying the matrix, refining and modifying, and micro-alloying in the aluminum alloy, which helps to refine the aluminum alloy structure, improve its mechanical properties and extrusion processing performance; the Si and Fe phases can be evenly distributed in the aluminum alloy matrix, forming a network distribution on the grain boundary surface, hindering the growth of grains at the grain boundaries, the structure is refined, and the corrosion resistance and brightness of the aluminum alloy can also be improved. During the extrusion forming process, the structure of the aluminum alloy can be further refined. The aluminum profiles with refined structures can show better compactness and integrity after oxidation, which is more conducive to improving the protection performance of the aluminum profiles, improving their corrosion resistance, and increasing their brightness.

[0016] Further, the surface treatment includes electrolytic oxidation, electrophoretic painting, and sealing.

[0017] The electrolytic oxidation includes anode plasma electrolytic oxidation and cathode plasma electrolytic deposition.

[0018] The electrophoretic painting is cathodic electrophoresis.

[0019] In the above technical solution, there are many surface protection technologies for aluminum and its alloys, including electroplating, spraying, electroless plating, anodic oxidation, micro-arc oxidation, vapor deposition, etc. Among them, micro-arc oxidation (plasma electrolytic oxidation) forms an oxide layer on the surface of the aluminum alloy. Compared with other technologies, the growth rate of the oxide layer is higher, the bonding force with the aluminum alloy matrix is stronger, and it has better wear resistance and corrosion resistance. However, micro-arc oxidation is an anodic reaction, which will cause anodic dissolution and the generation of a passivation film, resulting in a porous surface of the oxide layer, affecting the corrosion resistance of the aluminum profiles. Therefore, the present application adds cathode plasma electrolytic deposition after the anode plasma electrolytic oxidation process.

[0020] During the use of anodic electrophoretic coating, problems such as anodic dissolution and the discoloration of the paint film due to the oxygen generated by electrolysis often occur, resulting in corrosion on the surface of the profile and a reduction in the corrosion resistance of the aluminum profile. Therefore, in this application, cathodic electrophoresis is used to coat the aluminum profile.

[0021] Further, the anodic plasma electrolytic oxidation includes the following process steps:

[0022] Using the aluminum profile as the anode, anodic plasma electrolytic oxidation is carried out in a sodium silicate mixed solution to form a barrier layer.

[0023] Further, the sodium silicate mixed solution includes 25 - 35 g / L of sodium silicate, 13 - 22 g / L of sodium phosphate, and the pH is adjusted to 7.5 - 8.5 using sodium hydroxide;

[0024] The process conditions for anodic plasma electrolytic oxidation are: frequency 500 - 600 Hz, duty cycle 20% - 30%, current density 10 - 15 A / dm 2 , and the duration is 2.5 - 3.0 min.

[0025] Further, the cathodic plasma electrolytic deposition includes the following process steps:

[0026] Taking the aluminum profile obtained in the previous step as the cathode and platinum as the anode, cathodic plasma electrolytic deposition is carried out in the electrolyte to form an oxide layer.

[0027] Further, in the electrolyte, the immersed area of the anode ≥ 2 times the immersed area of the aluminum profile; to ensure that the plasma reaction occurs on the cathode; the distance between the anode and the aluminum profile is about 5 cm.

[0028] Further, the process conditions for cathodic plasma electrolytic deposition are: voltage 150 - 200 V, frequency 500 - 600 Hz, duty cycle 50% - 60%, oxidation time 10 - 30 min.

[0029] Further, the electrolyte includes the following components: 100 - 300 g / L of aluminum nitrate, 10 - 50 g / L of yttrium nitrate, 10 - 50 mL / L of glycerol, and 15 - 25 g / L of polyethylene glycol.

[0030] Further, in the electrolyte, the mass ratio of aluminum nitrate to yttrium nitrate is (5.2 - 5.6):1.

[0031] In the above technical solution, the aluminum profile is pretreated by anodic plasma electrolytic oxidation to oxidize its surface, which is denoted as the barrier layer. At the initial stage of the cathode plasma electrolytic deposition reaction, the surface of the cathode aluminum profile is covered by water vapor, glycerol vapor, and hydrogen gas generated by electrolyzed water. When the inter-electrode voltage is high enough, the gas film layer is broken down and discharged, and glycerol decomposes and further decomposes into active carbon and active oxygen. The plasma sheath layer is located at the cathode surface and the gas-liquid boundary. The aluminum profile is continuously heated, its surface temperature rises, a large number of active aluminum atoms are generated, combine with active oxygen to form aluminum oxide, and grow rapidly; while carbon can exist in the alumina lattice in the form of replacing oxygen, which improves the conductivity of the oxide layer and helps to densify the oxide layer prepared by electrolytic oxidation and smooth the surface. During subsequent high-temperature treatment, carbon diffuses and reacts and is removed. If the glycerol content is too high, it will cause its residue in the oxide layer, forming defects, which is not conducive to maximizing the performance of the oxide layer.

[0032] Through the cathode plasma electrolytic deposition technology, direct contact between the cathode aluminum profile and the electrolyte is avoided, the pores of the barrier layer obtained in the previous step are sealed, and it helps to obtain a denser oxide layer, improving its surface brightness and corrosion resistance.

[0033] Yttrium nitrate is added to the electrolyte and is dissolved in the generated alumina lattice during electrolytic oxidation, improving the surface conductivity of the aluminum profile; the generated yttrium oxide and alumina form yttrium aluminum oxide, further improving the surface conductivity of the oxide layer, making the oxide layer densified and the surface smooth, increasing its specular reflection, thereby improving the corrosion resistance and gloss of the aluminum profile. The atomic radius of yttrium is lower than that of other rare earth elements, and its solid solution effect in alumina is better.

[0034] The addition of polyethylene glycol to the electrolyte can limit the morphology of the aforementioned gas film layer, help reduce the cathode current density, and thus improve the uniformity of the oxide layer.

[0035] Furthermore, the electrophoretic painting includes the following processes:

[0036] Taking the aluminum profile obtained in the previous step as the cathode, placing it in the electrophoretic solution, and performing electrophoretic painting to obtain a sealing layer.

[0037] Furthermore, the process conditions for electrophoretic painting are: the temperature of the electrophoretic solution is 20 - 30 °C, the electrophoretic duration is 1 - 3 min, and the electrophoretic voltage is 160 - 220 V.

[0038] Furthermore, the electrophoretic solution is 100 - 150 g / L aqueous cationic resin;

[0039] Using lactic acid to adjust the solution pH to 5.0 - 6.0.

[0040] In the above technical solution, the water-based cationic resin in the electrophoresis solution has cations, so it carries a positive charge. Under the action of an external electric field, it moves towards the cathode, forming a uniform and dense film layer on the surface of the aluminum profile (oxide layer). Its adhesion and corrosion resistance are excellent, which is recorded as the sealing layer.

[0041] Furthermore, the water-based cationic resin is one or a mixture of cationic water-based epoxy resin, cationic water-based acrylic resin, and cationic water-based polyurethane resin.

[0042] Furthermore, the water-based cationic resin is prepared by the following process:

[0043] Mix 1 / 4 of the component mass of emulsifier and deionized water, and at a temperature of 40 - 45 °C, with a rotation speed of 650 - 750 r / min, stir and add methyl methacrylate, styrene, butyl acrylate, unsaturated epoxy resin, vinyltriisopropoxysilane, dimethylaminoethyl methacrylate, and hexafluorobutyl methacrylate, and stir for 30 - 40 min to obtain a pre-emulsion;

[0044] Mix 1 / 4 of the component mass of initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat up to 65 - 75 °C, add 1 / 4 of the initiator, and stir and react at a rotation speed of 200 - 300 r / min for 30 - 40 min; slowly add the remaining pre-emulsion, and add the remaining initiator every 30 min, and finish adding in 4 h, then continue to keep warm and react for 60 - 75 min; add diethanolamine and react for 100 - 150 min;

[0045] Cool down to 50 - 60 °C, add glacial acetic acid, and stir and react for 150 - 180 min; cool to obtain the water-based cationic resin.

[0046] Furthermore, the water-based cationic resin includes the following mass components: 10 - 15 parts of methyl methacrylate, 4.5 - 10 parts of styrene, 9 - 19 parts of butyl acrylate, 27 - 36 parts of unsaturated epoxy resin, 5 - 10 parts of vinyltriisopropoxysilane, 3 - 7 parts of dimethylaminoethyl methacrylate, 4 - 12 parts of hexafluorobutyl methacrylate, 0.8 - 1.2 parts of initiator, 0.5 - 1.0 part of emulsifier, 10 - 20 parts of diethanolamine, and 3.2 - 5.7 parts of glacial acetic acid;

[0047] The solid content of the water-based cationic resin is 60%.

[0048] In the above technical solution, the waterborne cationic resin is an epoxy resin-acrylate resin. Based on the characteristics of the epoxy resin, the prepared sealing layer has excellent gloss and hardness. The epoxy resin reacts with alkenyl acid to introduce alkenyl groups. Using its unsaturated bonds, it copolymerizes with acrylate monomers to prepare an emulsion, enabling the prepared sealing layer to obtain excellent comprehensive properties. The unsaturated epoxy resin is obtained by reacting epoxy resin with octadecenoic acid under the action of a catalyst. The long alkyl chain has good flexibility and is more easily filled in the pores of the oxide layer, with good film-forming properties, which helps the waterborne cationic resin to seal and form a film on the surface of the aluminum profile, making the prepared sealing layer have good compactness and water and corrosion resistance.

[0049] In the above technical solution, methyl methacrylate and styrene are hard monomers, which can improve the hardness, water resistance and gloss of the sealing layer. Butyl acrylate is a soft monomer with good flexibility, which can promote the film formation of the waterborne cationic resin on the surface of the aluminum profile. Vinyltriisopropoxysilane is introduced, and the hydrolyzed active -Si(OH) groups condense, which can increase the crosslinking density of the system, making the rigidity and hydrophobicity of the molecular chain increase. In the polymer system of the sealing layer, it is difficult for water molecules to penetrate and swell between its molecular chains, effectively improving the water resistance of the sealing layer; and it can also improve the bonding strength between the sealing layer and the oxide layer. Adding hexafluorobutyl methacrylate, the fluorine-containing chain segments migrate to the surface of the film layer under the action of thermodynamics, making the surface energy of the film layer significantly decrease, the water contact angle increase, and the water absorption rate decrease, which helps to improve the water resistance of the sealing layer, block the corrosive medium, and further improve the corrosion resistance of the aluminum profile. Dimethylaminoethyl methacrylate is a functional monomer, which is used to realize the cationic characteristics of the resin after acidification.

[0050] Furthermore, the unsaturated epoxy resin is prepared by the following process:

[0051] Mix epoxy resin, 4-(4-hydroxyphenyl)phthalazin-1(2H)-one and a catalyst, and under the protection of a nitrogen atmosphere, heat to 65 - 75 °C and react at a constant temperature for 5 - 7 h; wash and dry to obtain naphthyridine epoxy resin;

[0052] Mix naphthyridine epoxy resin, 6-thiolic acid, a catalyst and an inhibitor, heat to 60 - 80 °C and react in the dark for 3 - 5 h; wash and dry to obtain unsaturated epoxy resin.

[0053] Furthermore, the mass ratio of epoxy resin to 4-(4-hydroxyphenyl)phthalazin-1(2H)-one (CAS No: 152594-70-2) is 10:(2.3 - 3.0);

[0054] The catalyst is triphenylphosphine, and the dosage is 1.5% - 2.5% of the epoxy resin.

[0055] Further, the mass ratio of quinoline epoxy resin to 6-thiol oleic acid (CAS No: 102838-90-4) is 10:(1.8 - 3.6);

[0056] The catalyst is triphenylphosphine, and its dosage is 1.5% - 2.5% of the quinoline epoxy resin;

[0057] The inhibitor is 4-methoxyphenol, and its dosage is 0.8% - 1.2% of the epoxy resin.

[0058] In the above technical solution, the unsaturated resin is obtained by the reaction of epoxy resin, 4-(4-hydroxyphenyl)phthalazin-1(2H)-one, and 6-thiol oleic acid. By reacting epoxy resin with active groups such as amino, hydroxyl, and mercapto groups, sulfur and quinoline are introduced, which helps to increase the refractive index of the sealing layer and promote the improvement of its gloss; and based on the steric hindrance effect, it can hinder the penetration of corrosive media and promote the improvement of the corrosion resistance of the sealing layer.

[0059] Further, after electrophoretic painting, wash with water and bake at a temperature of 140 - 160°C for 20 - 30 min.

[0060] In the above technical solution, high-temperature baking effectively removes the moisture in the film layer and further crosslinks the active groups, thereby obtaining a more firm, reliable, and high-quality sealing layer. Specific Embodiments

[0061] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0062] In the following specific embodiments,

[0063] Epoxy resin: E-44, sourced from Qingdao Yousuo Chemical Technology Co., Ltd.;

[0064] The emulsifier is a mixture of non-ionic OP-10 and ionic emulsifier 31524 with a mass ratio of 1:3; the initiator is V50, sourced from Sinopharm Chemical Reagent Co., Ltd.;

[0065] The catalyst is triphenylphosphine, and the inhibitor is 4-methoxyphenol;

[0066] In Examples 1 - 3, Step 1: Mix and melt the raw materials, pour them, and perform homogenization treatment. The process is as follows: Heat to 525°C and hold for 75 h; raise the temperature to 540°C and hold for 7 h; place in a cooling furnace and cool to below 100°C, take out, and air-cool to room temperature to form an ingot;

[0067] Step 2: Extrusion. The process is as follows: The ingot is preheated to 460°C, the die is heated to 455°C, the extrusion ratio is 15, and the extrusion speed is 3.2 m / min; it is air-cooled to room temperature; heat treatment, which includes solution treatment and aging; the solution treatment process is: holding at 525°C for 7 h and quenching in water at 25°C; the aging process is: heating temperature 170°C, holding time 5 h; air-cooled to room temperature to form an aluminum profile; the aluminum profile includes the following components: by mass, Si: 0.41%, Mg: 0.57%, Fe: 0.04%, Cu: 0.01%, Mn: 0.01%, Cr: 0.3%, Ti: 0.01%, Zn: 0.1%, Y: 0.3%, and the balance is Al.

[0068] Example 1: A method for preparing a bright and corrosion-resistant aluminum profile, including the following processes:

[0069] Step 3: Surface treatment:

[0070] (1) Using the aluminum profile as the anode, anodic plasma electrolytic oxidation is carried out in a sodium silicate mixed solution to form a barrier layer; the sodium silicate mixed solution includes 25 g / L sodium silicate and 13 g / L sodium phosphate, and the pH is adjusted to 7.5 using sodium hydroxide; the process conditions for anodic plasma electrolytic oxidation are: frequency 600 Hz, duty cycle 20%, current density 15 A / dm 2 , duration 3.0 min;

[0071] (2) Taking the aluminum profile obtained in the previous step as the cathode and platinum as the anode, cathodic plasma electrolytic deposition is carried out in the electrolyte to form an oxide layer; the process conditions are: voltage 200 V, frequency 600 Hz, duty cycle 50%, oxidation time 30 min; the electrolyte includes the following components: 100 g / L aluminum nitrate, 19.2 g / L yttrium nitrate, 10 mL / L glycerol, and 15 g / L polyethylene glycol;

[0072] (3) Mix epoxy resin, 4-(4-hydroxyphenyl)phthalazin-1(2H)-one, and 1.5% catalyst, heat to 65°C under nitrogen atmosphere protection, and react at a constant temperature for 5 h; wash and dry to obtain naphthalene epoxy resin; the mass ratio of epoxy resin to 4-(4-hydroxyphenyl)phthalazin-1(2H)-one is 10:2.3; mix naphthalene epoxy resin, 6-thiooleic acid, 1.5% catalyst, and 0.8% inhibitor, heat to 60°C, and react in the dark for 5 h; wash and dry to obtain unsaturated epoxy resin; the mass ratio of naphthalene epoxy resin to 6-thiooleic acid is 10:3.6;

[0073] Mix 1 / 4 of the component mass of emulsifier and deionized water, and at a temperature of 40 °C, stir at a speed of 650 r / min, and add methyl methacrylate, styrene, butyl acrylate, unsaturated epoxy resin, vinyltriisopropoxysilane, dimethylaminoethyl methacrylate, and hexafluorobutyl methacrylate. Stir for 30 min to obtain a pre-emulsion; mix 1 / 4 of the component mass of initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat up to 75 °C, add 1 / 4 of the initiator, and stir and react at a speed of 200 r / min for 30 min; slowly add the remaining pre-emulsion, and add the remaining initiator every 30 min. Finish adding in 4 h, and continue to keep the temperature and react for 60 min; add diethanolamine and react for 100 min; cool down to 50 °C, add glacial acetic acid, and stir and react for 150 min; cool to obtain an aqueous cationic resin with a solid content of 60%; the aqueous cationic resin includes the following mass components: 15 parts of methyl methacrylate, 10 parts of styrene, 19 parts of butyl acrylate, 27 parts of unsaturated epoxy resin, 10 parts of vinyltriisopropoxysilane, 7 parts of dimethylaminoethyl methacrylate, 12 parts of hexafluorobutyl methacrylate, 1.0 part of initiator, 0.8 part of emulsifier, 15 parts of diethanolamine, and 5 parts of glacial acetic acid;

[0074] Use the aluminum profile obtained in the previous step as the cathode, place it in the electrophoretic solution for electrophoretic coating. After electrophoretic coating, wash with water and bake at a temperature of 140 °C for 30 min to obtain a sealing layer; the process conditions for electrophoretic coating are: the temperature of the electrophoretic solution is 30 °C, the electrophoretic duration is 3 min, and the electrophoretic voltage is 220 V; the electrophoretic solution is 100 g / L of aqueous cationic resin, and use lactic acid to adjust the pH of the solution to 6.0 to obtain a bright and corrosion-resistant aluminum profile.

[0075] Example 2: A preparation method of a bright and corrosion-resistant aluminum profile, including the following processes:

[0076] Step 3. Surface treatment:

[0077] (1) Use the aluminum profile as the anode and perform anodic plasma electrolytic oxidation in the sodium silicate mixed solution to form a barrier layer; the sodium silicate mixed solution includes 30 g / L of sodium silicate and 15 g / L of sodium phosphate, and use sodium hydroxide to adjust the pH to 8; the process conditions for anodic plasma electrolytic oxidation are: frequency 550 Hz, duty cycle 25%, current density 12 A / dm 2 , duration 2.8 min;

[0078] (2) Take the aluminum profile obtained in the previous step as the cathode, platinum as the anode, and perform cathodic plasma electrolytic deposition in the electrolyte to form an oxide layer. The process conditions for cathodic plasma electrolytic deposition are as follows: voltage 170V, frequency 550Hz, duty cycle 50%, oxidation time 20min. The electrolyte includes the following components: 200g / L aluminum nitrate, 37g / L yttrium nitrate, 20mL / L glycerol, and 20g / L polyethylene glycol;

[0079] (3) Mix epoxy resin, 4-(4-hydroxyphenyl)phthalazin-1(2H)-one, and 2% catalyst, heat to 70°C under nitrogen atmosphere protection, and react at a constant temperature for 5h; wash and dry to obtain naphthalazine epoxy resin. The mass ratio of epoxy resin to 4-(4-hydroxyphenyl)phthalazin-1(2H)-one is 10:2.6;

[0080] Mix naphthalazine epoxy resin, 6-thiooleic acid, 2% catalyst, and 1% inhibitor, heat to 70°C, and react in the dark for 4h; wash and dry to obtain unsaturated epoxy resin. The mass ratio of naphthalazine epoxy resin to 6-thiooleic acid is 10:2.7;

[0081] Mix 1 / 4 of the component mass of emulsifier and deionized water, stir and add methyl methacrylate, styrene, butyl acrylate, unsaturated epoxy resin, vinyltriisopropoxysilane, dimethylaminoethyl methacrylate, and hexafluorobutyl methacrylate at 42°C and a rotation speed of 700r / min, and stir for 35min to obtain a pre-emulsion. Mix 1 / 4 of the component mass of initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat to 78°C, add 1 / 4 of the initiator, and stir and react at a rotation speed of 250r / min for 35min; slowly add the remaining pre-emulsion, and add the remaining initiator every 30min. Finish adding in 4h, continue to keep the temperature and react for 68min; add diethanolamine and react for 120min; cool to 55°C, add glacial acetic acid, and stir and react for 165min; cool to obtain an aqueous cationic resin with a solid content of 60%. The aqueous cationic resin includes the following mass components: 12 parts of methyl methacrylate, 7 parts of styrene, 14 parts of butyl acrylate, 32 parts of unsaturated epoxy resin, 7 parts of vinyltriisopropoxysilane, 5 parts of dimethylaminoethyl methacrylate, 8 parts of hexafluorobutyl methacrylate, 1 part of initiator, 0.8 part of emulsifier, 15 parts of diethanolamine, and 5 parts of glacial acetic acid;

[0082] Using the aluminum profile obtained in the previous step as the cathode, place it in an electrophoretic solution for electrophoretic coating. After electrophoretic coating, wash it with water and bake it at 150 °C for 25 min to obtain a sealing layer. The process conditions for electrophoretic coating are as follows: the temperature of the electrophoretic solution is 25 °C, the electrophoretic duration is 2 min, and the electrophoretic voltage is 190 V. The electrophoretic solution is a 120 g / L aqueous cationic resin, and the pH of the solution is adjusted to 5.5 using lactic acid to obtain a bright and corrosion-resistant aluminum profile.

[0083] Example 3: A method for preparing a bright and corrosion-resistant aluminum profile, including the following processes:

[0084] Step 3: Surface treatment:

[0085] (1) Using the aluminum profile as the anode, perform anodic plasma electrolytic oxidation in a sodium silicate mixed solution to form a barrier layer. The sodium silicate mixed solution includes 35 g / L sodium silicate and 22 g / L sodium phosphate, and the pH is adjusted to 8.5 using sodium hydroxide. The process conditions for anodic plasma electrolytic oxidation are as follows: the frequency is 500 Hz, the duty cycle is 30%, the current density is 10 A / dm 2 , and the duration is 2.5 min;

[0086] (2) Taking the aluminum profile obtained in the previous step as the cathode and platinum as the anode, perform cathodic plasma electrolytic deposition in an electrolyte solution to form an oxide layer. The process conditions for cathodic plasma electrolytic deposition are as follows: the voltage is 150 V, the frequency is 500 Hz, the duty cycle is 60%, and the oxidation time is 10 min. The electrolyte solution includes the following components: 280 g / L aluminum nitrate, 50 g / L yttrium nitrate, 50 mL / L glycerol, and 25 g / L polyethylene glycol;

[0087] (3) Mix epoxy resin, 4-(4-hydroxyphenyl)phthalazin-1(2H)-one, and 2.5% catalyst, heat it to 75 °C under the protection of a nitrogen atmosphere, and react at a constant temperature for 7 h. Wash and dry to obtain naphthalazine epoxy resin. The mass ratio of epoxy resin to 4-(4-hydroxyphenyl)phthalazin-1(2H)-one is 10:3. Mix naphthalazine epoxy resin, 6-thiooleic acid, 2.5% catalyst, and 1.2% inhibitor, heat it up to 80 °C, and react in the dark for 3 h. Wash and dry to obtain unsaturated epoxy resin. The mass ratio of naphthalazine epoxy resin to 6-thiooleic acid is 10:1.8;

[0088] Mix 1 / 4 of the component mass of emulsifier and deionized water, and at a temperature of 45 °C, stir and add methyl methacrylate, styrene, butyl acrylate, unsaturated epoxy resin, vinyltriisopropoxysilane, dimethylaminoethyl methacrylate, and hexafluorobutyl methacrylate at a rotation speed of 750 r / min for 40 min to obtain a pre-emulsion; mix 1 / 4 of the component mass of initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat up to 80 °C, add 1 / 4 of the initiator, and stir and react at a rotation speed of 300 r / min for 40 min; slowly add the remaining pre-emulsion, and add the remaining initiator every 30 min, and finish adding in 4 h, then continue to keep warm and react for 75 min; add diethanolamine and react for 150 min; cool down to 60 °C, add glacial acetic acid, and stir and react for 180 min; cool to obtain an aqueous cationic resin with a solid content of 60%; the aqueous cationic resin includes the following mass components: 10 parts of methyl methacrylate, 4.5 parts of styrene, 9 parts of butyl acrylate, 36 parts of unsaturated epoxy resin, 5 parts of vinyltriisopropoxysilane, 3 parts of dimethylaminoethyl methacrylate, 4 parts of hexafluorobutyl methacrylate, 1 part of initiator, 0.8 part of emulsifier, 15 parts of diethanolamine 105, and 5 parts of glacial acetic acid;

[0089] Use the aluminum profile obtained in the previous step as the cathode, place it in the electrophoretic solution for electrophoretic coating, after electrophoretic coating, wash with water, and bake at a temperature of 160 °C for 20 min to obtain a sealing layer; the process conditions for electrophoretic coating are: the temperature of the electrophoretic solution is 20 °C, the electrophoretic duration is 1 min, and the electrophoretic voltage is 160 V; the electrophoretic solution is 150 g / L of aqueous cationic resin; adjust the pH of the solution to 5.0 with lactic acid to obtain a bright and corrosion-resistant aluminum profile.

[0090] Comparative Example 1: A method for preparing a bright and corrosion-resistant aluminum profile includes the following process:

[0091] Step 3. Surface treatment: Replace the aqueous cationic resin in step (3) with an aqueous cationic epoxy resin, and the other processes are the same as in Example 1 to obtain a bright and corrosion-resistant aluminum profile;

[0092] The aqueous cationic epoxy resin is prepared by the following process: Mix epoxy resin and ethylene glycol monobutyl ether, add diethanolamine, heat up to 100 °C, and react for 120 min; cool down to 50 °C, add glacial acetic acid and deionized water, and stir and react for 150 min; cool, add deionized water to obtain an aqueous cationic resin with a solid content of 60%, and the mass ratio of epoxy resin, diethanolamine, and glacial acetic acid is 100:15:5; the ratio of epoxy resin to ethylene glycol monobutyl ether is 30 g / 10 mL.

[0093] Comparative Example 2: A method for preparing a bright and corrosion-resistant aluminum profile includes the following process:

[0094] Step 3, surface treatment:

[0095] (1) Take the aluminum profile obtained in the previous step as the cathode, use platinum as the anode, and perform cathodic plasma electrolytic deposition in the electrolyte to form an oxide layer; the process conditions are: voltage 200V, frequency 600Hz, duty cycle 50%, oxidation time 30min; the electrolyte includes the following components: 100g / L aluminum nitrate, 10mL / L glycerol, and 15g / L polyethylene glycol;

[0096] (2) Mix 1 / 4 of the component mass of emulsifier and deionized water, stir and add methyl methacrylate, styrene, butyl acrylate, vinyltriisopropoxysilane, acrylic acid, and hexafluorobutyl methacrylate at a temperature of 45°C and a rotation speed of 750r / min for 40min to obtain a pre-emulsion; mix 1 / 4 of the component mass of initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat up to 80°C, add 1 / 4 of the initiator, and stir and react at a rotation speed of 300r / min for 40min; slowly add the remaining pre-emulsion, and add the remaining initiator every 30min, finish adding in 4h, continue to keep warm and react for 75min, and cool to obtain an aqueous acrylic resin with a solid content of 60%; the aqueous cationic resin includes the following mass components: 10 parts of methyl methacrylate, 4.5 parts of acrylic acid, 9 parts of butyl acrylate, 5 parts of vinyltriisopropoxysilane, 3 parts of hydroxyethyl acrylate, 4 parts of hexafluorobutyl methacrylate, 0.8 part of initiator, and 0.5 part of emulsifier;

[0097] Take the aluminum profile obtained in the previous step as the anode, place it in the electrophoretic solution, perform electrophoretic coating, wash with water after electrophoretic coating, and bake at a temperature of 160°C for 20min to obtain a sealing layer; the process conditions for electrophoretic coating are: electrophoretic solution temperature 20°C, electrophoretic duration 1min, electrophoretic voltage 160V; the electrophoretic solution includes the following mass components: 8% aqueous acrylic resin, 0.25% dimethylaminoethanol, 2% isopropanol, 1% ethylene glycol monobutyl ether, and the pH is 8.0; obtain a bright and corrosion-resistant aluminum profile.

[0098] Comparative Example 3: A method for preparing a bright and corrosion-resistant aluminum profile, including the following processes:

[0099] Step 3, surface treatment:

[0100] (1) Take the aluminum profile as the anode and perform anodic plasma electrolytic oxidation in the sodium silicate mixture to form an oxide layer; the sodium silicate mixture includes 25g / L sodium silicate and 13g / L sodium phosphate, and use sodium hydroxide to adjust the pH to 7.5; the process conditions for anodic plasma electrolytic oxidation are: frequency 600Hz, duty cycle 20%, current density 15A / dm 2, duration 10 min; (2) is the same as (2) in Comparative Example 2 to form a sealing layer, obtaining a bright and corrosion-resistant aluminum profile.

[0101] Comparative Example 4: A method for preparing a bright and corrosion-resistant aluminum profile, including the following processes:

[0102] Step 3, surface treatment:

[0103] Using the aluminum profile as the anode, anodic plasma electrolytic oxidation is carried out in a sodium silicate mixed solution to form an oxide layer; the sodium silicate mixed solution includes 25 g / L sodium silicate and 13 g / L sodium phosphate, and the pH is adjusted to 7.5 using sodium hydroxide; the process conditions of anodic plasma electrolytic oxidation are: frequency 600 Hz, duty cycle 20%, current density 15 A / dm 2 , duration 10 min;

[0104] Take the aluminum profile obtained in the previous step, immerse it in a 5 wt% KH-560 hydrolysis solution (a 90 v% ethanol solution and KH-560 are hydrolyzed at 60 °C for 12 h, pH is 4) for 10 min; take it out, dry it with nitrogen, and bake it at 100 °C for 120 min to form a sealing layer, obtaining a bright and corrosion-resistant aluminum profile.

[0105] Comparative Example 5: A method for preparing a bright and corrosion-resistant aluminum profile, including the following processes:

[0106] Step 1, mixing and melting the raw materials, casting, and homogenization treatment, the process is: heating to 525 °C, holding for 75 h; raising the temperature to 540 °C, holding for 7 h; placing it in a cooling furnace and cooling to below 100 °C, taking it out, and air-cooling to room temperature to form an ingot;

[0107] Step 2, extrusion, the process is: preheating the ingot to 460 °C, the die heating temperature is 455 °C, the extrusion ratio is 15, and the extrusion speed is 3.2 m / min; air-cooling to room temperature; heat treatment, the heat treatment includes solution treatment and aging; the solution treatment process is: holding at 525 °C for 7 h, and quenching in water at 25 °C; the aging process is: heating temperature 170 °C, holding time 5 h; air-cooling to room temperature to form an aluminum profile; the aluminum profile includes the following components: by mass, Si: 0.43%, Mg: 0.56%, Fe: 0.06%, Cu: 0.04%, Mn: 0.07%, Cr: 0.3%, Ti: 0.05%, Zn: 0.5%, and the balance is Al;

[0108] Step 3, the surface treatment is the same as that in Comparative Example 4, obtaining a bright and corrosion-resistant aluminum profile.

[0109] Experiment: Take the bright and corrosion-resistant aluminum profiles obtained in Examples 1-3 and Comparative Examples 1-5, prepare specimens, and detect their properties respectively and record the detection results:

[0110] Luminance test: With ASTM D523 as the reference standard, a glossiness detector was used to conduct glossiness tests on the specimens. The test angle was 20°, and the tests were carried out 5 times. The arithmetic mean was taken.

[0111] Corrosion resistance test: The three-electrode electrochemical corrosion method was used to detect the corrosion resistance of the specimens. The specimen was the working electrode, graphite was the auxiliary electrode, and saturated calomel was the reference electrode. The test area of the specimen was 10 mm × 10 mm, and the medium was 3.5 wt% sodium chloride aqueous solution (pH = 7). Before the experiment, the specimen was immersed for 30 min. The scanning range was -2 to 2 V, and the rate was 120 mV / s.

[0112] Glossiness <![CDATA[Corrosion current density (A / cm 2 )]]> Example 1 158 <![CDATA[2.9×10 -9 > Example 2 160 <![CDATA[2.1×10 -9 > Example 3 172 <![CDATA[1.0×10 -9 > Comparative Example 1 142 <![CDATA[5.1×10 -9 > Comparative Example 2 96 <![CDATA[2.2×10 -8 > Comparative Example 3 84 <![CDATA[7.8×10 -8 > Comparative Example 4 67 <![CDATA[1.7×10 -7 > Comparative Example 5 56 <![CDATA[8.3×10 -7 >

[0113] According to the data in the above table, the following conclusions can be clearly obtained:

[0114] The bright and corrosion-resistant aluminum profiles obtained in Examples 1-3 were compared with those obtained in Comparative Examples 1-5. The test results show that

[0115] Compared with the comparative examples, the bright and corrosion-resistant aluminum profiles obtained in Examples 1-3 had higher glossiness data and lower corrosion current density measured in the three-electrode electrochemical corrosion test. This fully demonstrates that the present invention has achieved the improvement of the bright surface characteristics and corrosion resistance of aluminum profiles.

[0116] Compared with Example 1, in the cathodic electrophoresis (sealing) process of Comparative Example 1, the electrophoretic solution used was water-based cationic epoxy resin; in Comparative Example 2, the surface treatment was cathodic plasma electrolytic deposition and anodic electrophoresis; in Comparative Example 3, the surface treatment was anodic plasma electrolytic oxidation and anodic electrophoresis; in Comparative Example 4, the surface treatment was anodic plasma electrolytic oxidation and silane hydrolysis sealing; compared with Comparative Example 4, the aluminum profiles in Comparative Example 5 did not contain rare earth elements. The glossiness and corrosion current density of the bright and corrosion-resistant aluminum profiles obtained in Comparative Examples 1-5 deteriorated. It can be seen that the settings of the preparation, surface treatment process and the components used for the aluminum profiles in this application can promote the improvement of their bright surface characteristics and corrosion resistance.

[0117] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

Claims

1. A method for preparing a bright and corrosion-resistant aluminum profile, characterized in that: Including the following processes: The raw materials are mixed, smelted, cast, and homogenized to form an ingot; Extrusion, heat treatment, forming aluminum profiles; surface treatment, obtaining bright and corrosion-resistant aluminum profiles; Surface treatment includes electrolytic oxidation, electrophoretic painting and sealing.

2. The method for preparing a bright and corrosion-resistant aluminum profile according to claim 1, characterized in that: The aluminum profile includes the following components: by mass, Si: 0.2% to 0.6%, Mg: 0.35% to 0.90%, Fe: ≤0.05%, Cu: ≤0.10%, Mn: ≤0.10%, Cr: ≤0.10%, Ti: ≤0.10%, Zn: ≤0.10%, RE: 0.1% to 0.4%, and the balance is Al.

3. The method for preparing a bright and corrosion-resistant aluminum profile according to claim 1, characterized in that: The electrolytic oxidation includes anodic plasma electrolytic oxidation and cathodic plasma electrolytic deposition; the anodic plasma electrolytic oxidation is carried out in a sodium silicate mixed solution with an aluminum profile as an anode to form a barrier layer; the cathodic plasma electrolytic deposition is carried out in an electrolyte with the aluminum profile obtained in the previous step as a cathode and platinum as an anode to form an oxide layer.

4. The method for preparing a bright and corrosion-resistant aluminum profile according to claim 3, characterized in that: The process conditions of the cathode plasma electrolytic deposition are: voltage 150-200V, frequency 500-600Hz, duty cycle 50%-60%, and oxidation time 10-30min.

5. The method for preparing a bright and corrosion-resistant aluminum profile according to claim 3, characterized in that: The electrolyte comprises the following components: 100-300 g / L aluminum nitrate, 10-50 g / L yttrium nitrate, 10-50 mL / L glycerol and 15-25 g / L polyethylene glycol; the mass ratio of aluminum nitrate to yttrium nitrate is (5.2-5.6):

1.

6. The method for preparing a bright and corrosion-resistant aluminum profile according to claim 1, characterized in that: The electrophoretic painting process is as follows: the aluminum profile obtained in the above step is used as a cathode, and electrophoretic painting is performed in an electrophoretic solution to obtain a sealing layer; the electrophoretic solution is 100-150g / L of an aqueous cationic resin.

7. The method for preparing a bright and corrosion-resistant aluminum profile according to claim 1, characterized in that: The aqueous cationic resin is prepared by the following process: Mix 1 / 4 of the mass of the emulsifier and deionized water, stir at 40-45°C, at a speed of 650-750 r / min, add methyl methacrylate, styrene, butyl acrylate, unsaturated epoxy resin, vinyl triisopropoxy silane, dimethylaminoethyl methacrylate, hexafluorobutyl methacrylate, and stir for 30-40 minutes to obtain a pre-emulsion; Mix 1 / 4 of the mass of the initiator and deionized water, add the remaining emulsifier and deionized water, add 1 / 4 of the pre-emulsion, heat to 65-75°C, add 1 / 4 of the initiator, stir and react at a speed of 200-300 r / min for 30-40 minutes; slowly add the remaining pre-emulsion, and add the remaining initiator every 30 minutes, add all for 4 hours, and continue to keep warm and react for 60-75 minutes; add diethanolamine and react for 100-150 minutes; The temperature was lowered to 50-60°C, glacial acetic acid was added, and the mixture was stirred for reaction for 150-180 minutes; the mixture was cooled to obtain a water-based cationic resin.

8. The method for preparing a bright and corrosion-resistant aluminum profile according to claim 7, characterized in that: The unsaturated epoxy resin is prepared by the following process: The epoxy resin, 4-(4-hydroxyphenyl)phthalazine-1(2H)-one and the catalyst are mixed, heated to 65-75° C. under the protection of nitrogen atmosphere, and reacted at the constant temperature for 5-7 hours to obtain a naphthalene azide epoxy resin; The naphthalene azide epoxy resin, 6-sulfur oleic acid, a catalyst and a polymerization inhibitor are mixed, the temperature is raised to 60-80° C., and the mixture is reacted for 3-5 hours in the dark to obtain an unsaturated epoxy resin.

9. The method for preparing a bright and corrosion-resistant aluminum profile according to claim 7, characterized in that: The aqueous cationic resin comprises the following components by weight: 10 to 15 parts of methyl methacrylate, 4.5 to 10 parts of styrene, 9 to 19 parts of butyl acrylate, 27 to 36 parts of unsaturated epoxy resin, 5 to 10 parts of vinyl triisopropoxy silane, 3 to 7 parts of dimethylaminoethyl methacrylate, 4 to 12 parts of hexafluorobutyl methacrylate, 0.8 to 1.2 parts of initiator, 0.5 to 1.0 parts of emulsifier, 10 to 20 parts of diethanolamine and 3.2 to 5.7 parts of glacial acetic acid.

10. A bright and corrosion-resistant aluminum profile obtained according to the preparation method according to any one of claims 1 to 9.