Composite aluminum strip and preparation method thereof

Abstract

The invention provides a composite aluminum strip and a preparation method thereof. The composite aluminum strip comprises an aluminum strip body and a corrosion-resistant layer. A corrosion-resistant layer is compounded and formed on one side or two sides of the aluminum strip; the corrosion-resistant layer is prepared from the following raw materials in parts by mass: 100 parts of polymethylvinylsiloxane, 13 parts of silicon dioxide, 2 parts of titanium dioxide, 1 part of benzotriazole, 8 parts of a curing agent and 3 parts of a tackifier. The problems that in the prior art, during preparation, non-metal substances are mixed in materials, air holes are easily formed, a tube plate part is in frequent contact with industrial cooling water, corrosion to the air holes of the tube plate is further aggravated, and the service life of the tube plate is shortened can be solved; the anti-corrosion effect of the tube plate is enhanced, and the service life of the tube plate is prolonged.

Description

Technical Field

[0001] This invention relates to the field of composite materials, and more particularly to a composite aluminum strip and its preparation method. Background Technology

[0002] Aluminum strip is a deep-processed aluminum product formed by slitting aluminum coils. It is often used in the processing and manufacturing of related equipment such as aluminum-plastic composite pipes, cables and optical cables. Aluminum strip is usually made of aluminum alloy. Due to the good corrosion resistance of aluminum alloy, it is also used to manufacture heat exchanger-related components.

[0003] A heat exchanger is a device that transfers some of the heat from a hot fluid to a cold fluid. In automotive heat exchangers, aluminum strips are commonly used to manufacture the collecting tubes or tube sheets of welded heat exchangers. However, in the manufacturing process of aluminum strips in the prior art, non-metallic substances such as oxides and sulfides may be mixed in, which can easily cause defects such as pores. As for the tube sheet, it is often in contact with industrial cooling water. Impurities, salts, gases, and microorganisms in the industrial cooling water can corrode the tube sheet, further aggravating the corrosion of the tube sheet pores and reducing the service life of the tube sheet. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a composite aluminum strip and its preparation method, which solves the problem that in the prior art, non-metallic substances are often mixed in the material during preparation, which easily forms pores. Furthermore, the tube sheet is frequently exposed to industrial cooling water, which further exacerbates the corrosion of the pores and reduces the service life of the tube sheet. This invention enhances the corrosion resistance of the tube sheet and extends its service life.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] The present invention provides a composite aluminum strip, comprising an aluminum strip and a corrosion-resistant layer; the corrosion-resistant layer is formed by composite molding one or both sides of the aluminum strip; the corrosion-resistant layer comprises the following raw materials in parts by weight: 100 parts of polymethylvinylsiloxane, 13 parts of silicon dioxide, 2 parts of titanium dioxide, 1 part of benzotriazole, 8 parts of curing agent and 3 parts of tackifier.

[0007] The composite aluminum strip provided by the present invention preferably includes a curing agent comprising methyl tributanone oxime silane and dibutyltin dilaurate in a mass ratio of 10:1.

[0008] The composite aluminum strip provided by the present invention preferably uses aminopropyltriethoxysilane as the tackifier.

[0009] Preferably, the silicon dioxide in the composite aluminum strip provided by the present invention is granular with a particle size of 20 nm.

[0010] Preferably, the titanium dioxide in the composite aluminum strip provided by the present invention is in granular form with a particle size of 20 nm.

[0011] The application provides a preparation method of a composite aluminum strip.

[0012] S101: preparing a suspension solution containing corrosion-resistant layer raw materials;

[0013] S102: sequentially performing degreasing, water washing and activation treatment on the surface of the aluminum strip;

[0014] S103: uniformly spraying the suspension solution on the surface of the aluminum strip through a pressure spraying device;

[0015] S104: rolling the surface of the aluminum strip through a roller;

[0016] S105: placing the aluminum strip into a constant-temperature and constant-humidity box for drying treatment, the drying temperature is 25 DEG C, the drying time is 48 h, and the composite aluminum strip is prepared.

[0017] In the step S101, preferably, the volume content of the corrosion-resistant layer raw materials in the suspension solution is 60%, and the viscosity of the suspension solution is 4500 centipoise.

[0018] The above technical scheme has the following advantages or beneficial effects:

[0019] The composite aluminum strip provided by the application is prepared by compounding a corrosion-resistant layer on the surface of the aluminum strip, so that the corrosion-resistant layer covers the contact surface of the aluminum strip and the outside and fills the pores on the surface of the aluminum strip, the corrosion-resistant layer is used to replace the direct contact between the aluminum strip and the outside, the corrosion degree of the aluminum strip caused by the outside environment is reduced, and the service life of the aluminum strip is prolonged.

[0020] The poly-methyl vinyl siloxane is used as the main material for preparing the corrosion-resistant layer, the poly-methyl vinyl siloxane has good chemical resistance, has good chemical corrosion resistance when being in contact with industrial cooling water in the heat exchanger, in particular, the poly-methyl vinyl siloxane is compatible with water, and can effectively avoid phase separation and other changes of the corrosion-resistant layer when being in contact with the cooling water for a long time, thereby avoiding affecting the sealing property and corrosion resistance of the corrosion-resistant layer and prolonging the service life of the tube sheet made of the composite aluminum strip; further, the poly-methyl vinyl siloxane has good viscosity, can fill and bond the pores by being coated on the surface of the aluminum strip, can reduce the gap between the corrosion-resistant layer and the surface of the aluminum strip, and avoid the corrosion of the aluminum strip caused by the penetration of the cooling water; meanwhile, the poly-methyl vinyl siloxane has good heat resistance, can avoid the influence of the relatively high temperature carried by the cooling water in the heat exchange process on the performance of the corrosion-resistant layer; and the poly-methyl vinyl siloxane has good elasticity after being solidified, can slow down the scouring force from the flow of the cooling water, and improve the service life of the tube sheet made of the composite aluminum strip.

[0021] Silica, titanium dioxide, and benzotriazole were used as auxiliary materials for preparing the corrosion-resistant layer. Silica filled the voids within polymethylvinylsiloxane, increasing its density and thus preventing cooling water penetration, thereby improving the corrosion resistance of the composite aluminum strip. Titanium dioxide inhibited the growth of bacteria or fungi on the surface of the corrosion-resistant layer, reducing microbial corrosion of the aluminum strip surface. Simultaneously, silica and titanium dioxide possess antioxidant properties; their addition to polymethylvinylsiloxane inhibited the reaction between polymethylvinylsiloxane and oxygen, slowing down the oxidation process and extending the service life of the tube sheet made from the composite aluminum strip. Benzotriazole adsorbed onto the aluminum strip surface, forming a corrosion-inhibiting film, further suppressing corrosion of the aluminum strip surface pores.

[0022] The corrosion-resistant layer material also includes a curing agent and a tackifier; the curing agent is used to cure the liquid polymethyl vinyl siloxane, so that the corrosion-resistant layer is formed on the surface of the aluminum strip; the tackifier is used to improve the adhesion between the cured polymethyl vinyl siloxane and the surface of the aluminum strip, so as to resist the scouring force of the cooling water and avoid the corrosion-resistant layer from falling off due to the impact of the cooling water.

[0023] In existing technologies, the presence of non-metallic substances within the material during fabrication easily leads to the formation of pores. Since the tube sheet is frequently in contact with industrial cooling water, this further exacerbates corrosion of the pores, reducing the tube sheet's service life. The composite aluminum strip provided by this invention uses polymethylvinylsiloxane as the main material for preparing the corrosion-resistant layer, and silica, titanium dioxide, and benzotriazole as auxiliary materials. This corrosion-resistant layer covers the contact surface between the aluminum strip and the external environment, filling the pores on the aluminum strip surface. This allows the corrosion-resistant layer to replace direct contact between the aluminum strip and cooling water, reducing the degree of corrosion and extending the service life of the tube sheet made from the aluminum strip. Attached Figure Description

[0024] The invention, its features, shape, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals denote like parts throughout the drawings. The drawings are not intentionally drawn to scale; the focus is on illustrating the spirit of the invention.

[0025] Figure 1 This is a wireframe flowchart illustrating the method for preparing composite aluminum strip according to Embodiment 2 of the present invention. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the invention.

[0027] Example 1:

[0028] The present invention provides a composite aluminum strip in embodiment 1, comprising an aluminum strip and a corrosion-resistant layer; the corrosion-resistant layer is formed by composite molding on one or both sides of the aluminum strip; the corrosion-resistant layer comprises the following raw materials in parts by weight: 100 parts of polymethylvinylsiloxane, 13 parts of silicon dioxide, 2 parts of titanium dioxide, 1 part of benzotriazole, 8 parts of curing agent and 3 parts of tackifier.

[0029] The composite aluminum strip provided in Embodiment 1 of the present invention, by forming a corrosion-resistant layer on the surface of the aluminum strip, covers the contact surface between the aluminum strip and the outside and fills the pores on the surface of the aluminum strip, so that the corrosion-resistant layer replaces the direct contact between the aluminum strip and the outside, reduces the degree of corrosion of the aluminum strip by the external environment, and extends the service life of the aluminum strip.

[0030] Polymethylvinylsiloxane (PMV) is used as the main material for preparing the corrosion-resistant layer. PMV exhibits excellent chemical resistance, demonstrating good resistance to chemical corrosion when in contact with industrial cooling water in the heat exchanger. In particular, PMV is water-compatible, effectively preventing phase separation and other changes in the corrosion-resistant layer upon contact with cooling water during prolonged use. This avoids affecting the sealing and corrosion resistance of the corrosion-resistant layer, extending the service life of the tube sheet made of composite aluminum strip. Furthermore, PMV has good adhesion; by coating it on the surface of the aluminum strip, it can fill and adhere pores, reducing the gap between the corrosion-resistant layer and the aluminum strip surface, preventing accelerated corrosion of the aluminum strip due to cooling water seeping between them. Simultaneously, PMV has good heat resistance, preventing the high temperatures carried by the cooling water during heat exchange from affecting the performance of the corrosion-resistant layer. Moreover, PMV exhibits good elasticity after curing, which can mitigate the scouring force from the cooling water flow, further extending the service life of the tube sheet made of composite aluminum strip.

[0031] Silica, titanium dioxide, and benzotriazole were used as auxiliary materials for preparing the corrosion-resistant layer. Silica filled the voids within polymethylvinylsiloxane, increasing its density and thus preventing cooling water penetration, thereby improving the corrosion resistance of the composite aluminum strip. Titanium dioxide inhibited the growth of bacteria or fungi on the surface of the corrosion-resistant layer, reducing microbial corrosion of the aluminum strip surface. Simultaneously, silica and titanium dioxide possess antioxidant properties; their addition to polymethylvinylsiloxane inhibited the reaction between polymethylvinylsiloxane and oxygen, slowing down the oxidation process and extending the service life of the tube sheet made from the composite aluminum strip. Benzotriazole adsorbed onto the aluminum strip surface, forming a corrosion-inhibiting film, further suppressing corrosion of the aluminum strip surface pores.

[0032] The corrosion-resistant layer material also includes a curing agent and a tackifier; the curing agent is used to cure the liquid polymethyl vinyl siloxane, so that the corrosion-resistant layer is formed on the surface of the aluminum strip; the tackifier is used to improve the adhesion between the cured polymethyl vinyl siloxane and the surface of the aluminum strip, so as to resist the scouring force of the cooling water and avoid the corrosion-resistant layer from falling off due to the impact of the cooling water.

[0033] In existing technologies, the presence of non-metallic substances within the material during fabrication easily leads to the formation of pores. Since the tube sheet is frequently exposed to industrial cooling water, this further exacerbates corrosion of the pores, reducing the tube sheet's service life. The composite aluminum strip provided in Embodiment 1 of this invention uses polymethylvinylsiloxane as the main material for preparing the corrosion-resistant layer, and silica, titanium dioxide, and benzotriazole as auxiliary materials. This corrosion-resistant layer covers the contact surface between the aluminum strip and the external environment, filling the pores on the aluminum strip surface. This allows the corrosion-resistant layer to replace direct contact between the aluminum strip and the cooling water, reducing the degree of corrosion and extending the service life of the tube sheet made from the aluminum strip.

[0034] The composite aluminum strip provided in Embodiment 1 of the present invention preferably includes a curing agent comprising methyl tributanone oxime silane and dibutyltin dilaurate in a mass ratio of 10:1; wherein, methyl tributanone oxime silane acts as a crosslinking agent to induce crosslinking reactions between polymethyl vinyl siloxane molecular chains, forming a three-dimensional network structure; wherein, dibutyltin dilaurate acts as a catalyst to accelerate the crosslinking reaction.

[0035] The composite aluminum strip provided in Embodiment 1 of the present invention preferably uses aminopropyltriethoxysilane as an adhesive to further enhance the adhesion between the corrosion-resistant layer and the aluminum strip, prevent the corrosion-resistant layer from falling off, and extend the service life of the tube sheet made of the composite aluminum strip.

[0036] The composite aluminum strip provided in Embodiment 1 of the present invention preferably contains granular silica with a particle size of 20 nm. Granular silica is easy to mix and uniformly distribute in polymethylvinylsiloxane, which can effectively improve the density and inhibit the reaction between polymethylvinylsiloxane and oxygen. At the same time, the smaller particle size allows silica to enter the pores, further improving the corrosion resistance of the pores.

[0037] The composite aluminum strip provided in Embodiment 1 of the present invention preferably contains titanium dioxide in granular form with a particle size of 20 nm. Granular titanium dioxide is easy to mix and uniformly distribute within polymethylvinylsiloxane, which can effectively inhibit bacteria or fungi on the surface of the corrosion-resistant layer, reduce microbial corrosion of the aluminum strip surface, and inhibit the reaction between polymethylvinylsiloxane and oxygen. At the same time, the smaller particle size allows titanium dioxide to enter the pores, further improving the corrosion resistance to pores. Furthermore, its combination with silica significantly reduces the dual corrosion risk of cooling water penetration corrosion and microbial corrosion on the surface of the corrosion-resistant layer.

[0038] Example 2:

[0039] like Figure 1 As shown, Embodiment 2 of the present invention provides a method for preparing a composite aluminum strip, comprising the following steps:

[0040] S101: Prepare a suspension solution containing a corrosion-resistant layer raw material;

[0041] S102: The aluminum strip surface is sequentially degreased, washed with water, and activated.

[0042] S103: The suspension solution is uniformly sprayed onto the surface of the aluminum strip using a pressure spraying device;

[0043] S104: Rolling the surface of the aluminum strip using rollers;

[0044] S105: The aluminum strip is placed in a constant temperature and humidity chamber for drying at a temperature of 25°C for 48 hours to obtain a composite aluminum strip.

[0045] The present invention provides a method for preparing a composite aluminum strip. In step S101, since the main material for preparing the corrosion-resistant layer, polymethylvinylsiloxane, has high viscosity, in order to coat the corrosion-resistant material onto the surface of the aluminum strip, the corrosion-resistant material needs to be prepared into a suspension solution. Specifically, polymethylvinylsiloxane and curing agent are first added to a stirring container and stirred evenly to fully disperse the curing agent in the polymethylvinylsiloxane; then, silica, titanium dioxide, benzotriazole and tackifier are added in sequence, and stirring is continued to mix the components evenly. During this period, toluene solvent is added for dilution; finally, a high-speed mixer is used to stir at a speed of 1500 rpm for 25 minutes to prepare a suspension solution.

[0046] In step S102, the aluminum strip surface is pretreated. Specifically, the aluminum strip is immersed in a tank containing a degreasing agent (such as an alkaline solution of sodium hydroxide or sodium carbonate) at 50°C for 10 minutes to remove oil, grease, and other organic contaminants from the aluminum strip surface. The degreased aluminum strip is then removed and rinsed with deionized water to remove any residual degreasing agent and avoid affecting the performance of subsequent coatings and corrosion-resistant layers. Finally, the aluminum strip is immersed in a dilute sulfuric acid or dilute nitric acid solution for light etching for 2 minutes to activate the aluminum strip surface and enhance its adhesion to the corrosion-resistant layer. It is then rinsed again with deionized water and dried.

[0047] In step S103, the suspension solution is uniformly sprayed onto the surface of the aluminum strip using a pressure spraying device (a high-pressure airless spraying device can be used here), so that the suspension solution initially adheres to the surface of the aluminum strip.

[0048] In step S104, the aluminum strip surface is rolled by rollers to make the suspension solution attached to the aluminum strip surface evenly distributed. At the same time, the suspension solution can penetrate into the pores of the aluminum strip surface. Rolling can also make the corrosion-resistant layer denser and make it more tightly bonded to the aluminum strip surface.

[0049] In step S105, polymethylvinylsiloxane is cross-linked and cured under constant temperature and humidity conditions to avoid the curing effect being affected by factors such as temperature and humidity; it should be noted that under these conditions, the toluene solvent will gradually evaporate.

[0050] The method for preparing composite aluminum strip provided in Embodiment 2 of the present invention preferably includes, in step S101, the volume content of the corrosion-resistant layer raw material in the suspension solution is 60%, and the viscosity of the suspension solution is 4500 centipoise, which can maintain the viscosity that allows for atomized spraying of the aluminum strip surface by a pressure spraying device while generating a dense corrosion-resistant layer.

[0051] Example 3:

[0052] Example 3 of this invention uses 3003 aluminum strip as an example. The composite aluminum strip is prepared using the same mass fraction of the corrosion-resistant layer raw material as in Example 1 and the same preparation method as in Example 2. The composite aluminum strip is tested using the neutral salt spray test (NSS) of GB / T 10125 "Artificial Atmosphere Corrosion Test Salt Spray Test". Specifically, a 5% sodium chloride solution is used, with a pH value between 6.5 and 7.2, and the test temperature is (35±2)℃.

[0053] Compared with conventional 3003 aluminum strip of the same size, the weight loss of the 3003 aluminum strip after 1000 hours of neutral salt spray testing was 0.05-0.07 g / (m²). 2 •h); while the weight loss rate of the composite aluminum strip is 0.01g / (m 2 ·h).

[0054] In summary, the composite aluminum strip and its preparation method provided by this invention can solve the problems of existing technologies where non-metallic substances are easily incorporated into the material during preparation, which easily leads to the formation of pores. Furthermore, the tube sheet is frequently exposed to industrial cooling water, which further exacerbates the corrosion of the pores and reduces the service life of the tube sheet. This invention enhances the corrosion resistance of the tube sheet and extends its service life.

[0055] Those skilled in the art should understand that variations can be implemented by combining existing technology and the above embodiments, and will not be elaborated here. Such variations do not affect the essence of the present invention, and will not be elaborated here.

[0056] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a manner common to the art; any possible variations and modifications made by those skilled in the art without departing from the technical solution of the present invention, or equivalent embodiments with equivalent changes, do not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A composite aluminum strip, characterized in that, It includes an aluminum strip and a corrosion-resistant layer; the corrosion-resistant layer is formed by composite molding one or both sides of the aluminum strip; the corrosion-resistant layer includes the following raw materials in parts by weight: 100 parts of polymethylvinylsiloxane, 13 parts of silicon dioxide, 2 parts of titanium dioxide, 1 part of benzotriazole, 8 parts of curing agent and 3 parts of tackifier.

2. The composite aluminum strip as described in claim 1, characterized in that, The curing agent comprises methyl tributanone oxime silane and dibutyltin dilaurate in a mass ratio of 10:

1.

3. The composite aluminum strip as described in claim 1, characterized in that, The thickener is aminopropyltriethoxysilane.

4. The composite aluminum strip as described in claim 1, characterized in that, The silicon dioxide is in granular form with a particle size of 20 nm.

5. The composite aluminum strip as described in claim 1, characterized in that, The titanium dioxide is in granular form with a particle size of 20 nm.

6. A method for preparing the composite aluminum strip as described in claim 1, characterized in that, Includes the following steps: S101: Prepare a suspension solution containing a corrosion-resistant layer raw material; S102: The aluminum strip surface is sequentially degreased, washed with water, and activated. S103: The suspension solution is uniformly sprayed onto the surface of the aluminum strip using a pressure spraying device; S104: Rolling the surface of the aluminum strip using rollers; S105: The aluminum strip is placed in a constant temperature and humidity chamber for drying at a temperature of 25°C for 48 hours to obtain a composite aluminum strip.

7. The method for preparing the composite aluminum strip as described in claim 6, characterized in that, In step S101, the volume content of the corrosion-resistant layer material in the suspension solution is 60%; the viscosity of the suspension solution is 4500 centipoise.

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