Preparation method of multi-layer functionalized silane protective film on surface of automobile plate

Abstract

The invention discloses a preparation method of a multi-layer functionalized silane protective film on the surface of an automobile sheet material, which realizes multiple protection on the sheet material by constructing silane film layers with different functions on the surface of the automobile sheet material layer by layer so as to obviously improve the surface protection performance of the automobile sheet material. According to the method, specific components are adopted for compounding, a first basic silane film layer and a second reinforced silane film layer which have a synergistic effect are formed, the thickness of the basic film layer is 1-2 microns, good adhesive force and corrosion resistance are ensured, the thickness of the reinforced film layer is 2-3 microns, the corrosion resistance and the adhesive force are enhanced, and the service life of the coating is prolonged. According to the method, the performance of the automobile plate can be remarkably improved, and the service life of the automobile plate can be prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile manufacturing and surface treatment, and specifically relates to a method for preparing a multi-layer functional silane protective film on the surface of an automobile plate. Background Art

[0002] With the rapid development of the automobile industry, automobile sheet materials, as key materials in automobile manufacturing, have increasingly higher performance and quality requirements. Automobile sheet materials not only need to have good mechanical properties, but also need to have excellent surface properties such as corrosion resistance, wear resistance and adhesion to ensure the safety and comfort of the car during use. Although traditional automobile sheet surface treatment technologies, such as electroplating and spraying, can improve the performance of the sheet materials to a certain extent, these technologies have problems such as serious environmental pollution, high energy consumption, long processing cycle and high cost. With the increasingly stringent environmental regulations and consumers' continuous pursuit of automobile quality, traditional surface treatment technologies have been unable to meet the development needs of the modern automobile industry.

[0003] In recent years, silane pretreatment technology has attracted widespread attention due to its environmental protection and high efficiency. Silane pretreatment technology is a surface treatment technology that uses silane coupling agents to form a layer of chemical conversion film on the metal surface. This silane film layer can form a strong chemical bond with the metal substrate, thereby significantly improving the corrosion resistance and adhesion of the metal surface. At the same time, silane pretreatment technology also has the advantages of simple processing technology, low cost, and no environmental pollution. However, the protective effect of a single-layer silane film is limited, especially in complex and harsh use environments, its long-term stability and protective performance will be affected, so new materials or technologies are urgently needed to improve the corrosion resistance of silane films. Summary of the invention

[0004] In order to overcome the above-mentioned defects of the prior art, improve the corrosion resistance, wear resistance and adhesion of automobile plates, and extend the service life of the car, it is particularly important to develop a preparation and application technology of a multi-layer functional silane protective film. The multi-layer functional silane protective film technology realizes multiple protection of the plate by constructing silane film layers with different functions on the surface of the automobile plate layer by layer. Each layer of silane film can select different silane coupling agents and functional groups according to needs, thereby giving the film layer specific properties, such as enhanced adhesion, improved hardness, enhanced corrosion resistance, and scratch resistance. This multi-layer structure design can not only significantly improve the overall performance of automobile plates, but also can be customized and optimized according to actual needs. In addition, the multi-layer functional silane protective film technology also has the advantages of simple preparation process, low cost, environmental protection and pollution-free. The technology uses a rich variety of silane coupling agents, which can be selected and matched according to needs, realizing the multifunctional modification of the surface of automobile plates. At the same time, the preparation process adopted by the technology is simple and easy, does not require complex equipment and operations, reduces production costs and energy consumption, conforms to the development trend and environmental protection requirements of modern industry, and has broad application prospects and market potential.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides a method for preparing a multilayer functional silane protective film on the surface of an automobile sheet, the method comprising the following steps:

[0006] ① Add the components of the first layer of base silane film into a stirring container in proportion, set the stirring temperature to 55°C to 65°C, the stirring speed to 400 to 600 rpm, and stir for 30 to 45 minutes to obtain the first layer of silane solution.

[0007] ② Transfer the first layer of silane solution to the spraying equipment, adjust the spray gun to 25-30 cm away from the plate, spray pressure 0.2-0.3 MPa, and apply the first layer of silane solution on the surface of the plate.

[0008] ③ Send the plate coated with the first layer of silane solution into the preheated drying room, control the drying temperature to 150℃~200℃, the drying time to 30~40 minutes, use the hot air circulation system to ensure uniform temperature distribution, and form the first layer of basic silane film.

[0009] ④ Add the components of the second layer of enhanced silane film into the stirring container in proportion, set the stirring temperature to 55°C to 65°C, the stirring speed to 400 to 600 rpm, and stir for 30 to 45 minutes to obtain a second layer of silane solution.

[0010] ⑤ Transfer the second layer of silane solution to the spraying equipment, adjust the spray gun to 25-30 cm from the plate, spray pressure 0.2-0.3 MPa, and apply the second layer of silane solution on the surface of the plate coated with the first layer of silane solution.

[0011] ⑥ Send the plate coated with the second layer of silane solution into a preheated drying room at a drying temperature of 150°C to 200°C for 30 to 40 minutes. The second layer of enhanced silane film is completely cured to obtain a multi-layer functional silane protective film on the surface of the automotive plate.

[0012] The above two layers of silane film have a synergistic effect and can significantly improve the surface protection performance of automotive panels. The base layer ensures good adhesion and corrosion resistance, and the reinforcement layer further improves corrosion resistance and adhesion, while giving the panel higher hardness and wear resistance.

[0013] In the above technical solution, further, the first base silane film layer includes the following components in parts by weight: 20-30 parts of compound silane coupling agent, 1-4 parts of catalyst, 5-10 parts of cosolvent, 1-5 parts of wetting agent, and 55-75 parts of deionized water. The compound silane coupling agent is prepared by mixing silane coupling agent (KH-550) and silane coupling agent (A-174) in a weight ratio of (2-3):1. The catalyst is prepared by mixing acetic acid (concentration greater than 80%) and hydrochloric acid (concentration of 37%) in a weight ratio of (2-3):1. The cosolvent is prepared by mixing ethanol and n-butanol in a weight ratio of (2-3):1. The wetting agent is prepared by mixing sodium dodecyl sulfate and non-ionic surfactant Tween 80 in a weight ratio of 1:1.

[0014] Further, the second enhanced silane film layer includes the following components in parts by weight: 20 to 30 parts of a compound silane coupling agent, 1 to 5 parts of a catalyst, 5 to 10 parts of a cosolvent, 1 to 5 parts of a reinforcing agent, and 55 to 75 parts of deionized water. The compound silane coupling agent is prepared by mixing a silane coupling agent (KH-560) and a silane coupling agent (GPTMS) in a weight ratio of (3 to 4):1. The catalyst is prepared by mixing 98.3% sulfuric acid and 55% nitric acid in a weight ratio of (2 to 3):1. The cosolvent is prepared by mixing methanol and ethylene glycol in a weight ratio of (1 to 2):1. The reinforcing agent is prepared by mixing nano-silicon dioxide and nano-alumina with a size of 30 to 50 nm in a weight ratio of 1:1.

[0015] Furthermore, the thickness of the first base silane film layer is controlled to be 1-2 μm.

[0016] Furthermore, the thickness of the second enhanced silane film layer is controlled to be 2-3 μm.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The method for preparing a multi-layer functionalized silane protective film on the surface of an automobile sheet provided by the present invention can not only significantly improve the performance and quality of the automobile sheet and extend the service life of the automobile, but also reduce production costs and energy consumption, reduce environmental pollution, and meet the development trend of modern industry and environmental protection requirements. Therefore, the development and application of this technology has important economic value and social significance. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with specific examples, but the present invention is not limited in any way. To avoid redundant description, the raw materials in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0020] A method for preparing a multi-layer functionalized silane protective film on the surface of an automobile plate, the method comprising the following steps:

[0021] ① Add the components of the first layer of base silane film into a stirring container in proportion, set the stirring temperature to 55°C to 65°C, the stirring speed to 400 to 600 rpm, and stir for 30 to 45 minutes to obtain the first layer of silane solution.

[0022] ② Transfer the first layer of silane solution to the spraying equipment, adjust the spray gun to 25-30 cm away from the plate, spray pressure 0.2-0.3 MPa, and apply the first layer of silane solution on the surface of the plate.

[0023] ③ Send the plate coated with the first layer of silane solution into the preheated drying room, control the drying temperature to 150℃~200℃, the drying time to 30~40 minutes, use the hot air circulation system to ensure uniform temperature distribution, and form the first layer of basic silane film.

[0024] ④ Add the components of the second layer of enhanced silane film into the stirring container in proportion, set the stirring temperature to 55°C to 65°C, the stirring speed to 400 to 600 rpm, and stir for 30 to 45 minutes to obtain a second layer of silane solution.

[0025] ⑤ Transfer the second layer of silane solution to the spraying equipment, adjust the spray gun to 25-30 cm from the plate, spray pressure 0.2-0.3 MPa, and apply the second layer of silane solution on the surface of the plate coated with the first layer of silane solution.

[0026] ⑥ Send the plate coated with the second layer of silane solution into a preheated drying room at a drying temperature of 150°C to 200°C for 30 to 40 minutes. The second layer of enhanced silane film is completely cured to obtain a multi-layer functional silane protective film on the surface of the automotive plate.

[0027] The matters not described in the following embodiments are the same as the description of the above specific implementation methods.

[0028] Example

[0029] A method for preparing a multi-layer functionalized silane protective film on the surface of an automobile plate, the method comprising the following steps:

[0030] ① Add the components of the first layer of base silane film into a stirring container in proportion, set the stirring temperature to 65°C, the stirring speed to 600 rpm, and stir for 45 minutes to obtain the first layer of silane solution.

[0031] The first base silane film layer includes the following components in parts by weight: 20 to 30 parts of a compound silane coupling agent, 1 to 4 parts of a catalyst, 5 to 10 parts of a cosolvent, 1 to 5 parts of a wetting agent, and 55-75 parts of deionized water; the components and contents of the first base silane film layer of Examples 1-10 are shown in Table 1.

[0032] Table 1 Components and contents of the first base silane film layer of Examples 1-10

[0033] Components Compound silane coupling agent catalyst Solvent Wetting Agents Deionized water Content range / portion 20-30 1-4 5-10 1-5 55-75 Example 1 24 3 7 2 60 Example 2 28 2 5 1 58 Example 3 22 4 8 2 62 Example 4 30 2 6 1 66 Example 5 26 3 8 1 70 Example 6 20 1 5 3 72 Example 7 22 2 7 2 74 Example 8 25 4 6 3 70 Example 9 27 1 10 4 64 Example 10 29 3 9 5 60

[0034] The compound silane coupling agent is prepared by mixing a silane coupling agent (KH-550) and a silane coupling agent (A-174) in a weight ratio of 3:1; the catalyst is prepared by mixing acetic acid with a concentration of 85% and hydrochloric acid with a concentration of 37% in a weight ratio of 3:1; the cosolvent is prepared by mixing ethanol and n-butanol in a weight ratio of 3:1; the wetting agent is prepared by mixing sodium dodecyl sulfate and a nonionic surfactant Tween 80 in a weight ratio of 1:1.

[0035] ② Transfer the first layer of silane solution to the spraying equipment, adjust the spray gun to 30cm away from the plate, spray pressure 0.3MPa, and apply the first layer of silane solution on the surface of the plate.

[0036] ③ Send the plate coated with the first layer of silane solution into the preheated drying room, control the drying temperature to 200°C, the drying time to 40 minutes, use the hot air circulation system to ensure uniform temperature distribution, and form the first layer of basic silane film.

[0037] ④ Add the components of the second layer of enhanced silane film into the stirring container in proportion, set the stirring temperature to 65°C, the stirring speed to 600 rpm, and stir for 45 minutes to obtain the second layer of silane solution.

[0038] The second layer of enhanced silane film layer includes the following components in parts by weight: 20 to 30 parts of a compound silane coupling agent, 1 to 5 parts of a catalyst, 5 to 10 parts of a co-solvent, 1 to 5 parts of a reinforcing agent, and 55 to 75 parts of deionized water; the components and contents of the second layer of enhanced silane film layer of Examples 1-10 are shown in Table 2.

[0039] Table 2 Composition and content of the second enhanced silane film layer of Examples 1-10

[0040] Component name Compound silane coupling agent catalyst Solvent Enhancer Deionized water Content range / portion 20-30 1-5 5-10 1-5 55-75 Example 1 24 2 7 3 60 Example 2 28 1 5 4 63 Example 3 22 3 8 2 66 Example 4 30 1 6 5 70 Example 5 26 2 7 4 72 Example 6 24 4 8 5 75 Example 7 30 5 5 4 60 Example 8 22 4 9 3 63 Example 9 28 3 10 3 65 Example 10 26 4 8 5 70

[0041] The compound silane coupling agent is prepared by mixing silane coupling agent KH-560 and silane coupling agent GPTMS in a weight ratio of 4:1; the catalyst is prepared by mixing 98.3% sulfuric acid and 55% nitric acid in a weight ratio of 3:1; the cosolvent is prepared by mixing methanol and ethylene glycol in a weight ratio of 2:1; the enhancer is prepared by mixing silicon dioxide with a size of 30nm and nano-alumina in a weight ratio of 1:1.

[0042] ⑤ Transfer the second layer of silane solution to the spraying equipment, adjust the spray gun to 30cm away from the plate, spray pressure 0.3MPa, and apply the second layer of silane solution on the surface of the plate coated with the first layer of silane solution.

[0043] ⑥ Send the plate coated with the second layer of silane solution into a preheated drying room at a drying temperature of 200°C for 40 minutes. The second layer of enhanced silane film is completely cured to obtain a multi-layer functional silane protective film on the surface of the automotive plate.

[0044] The thickness of the first basic silane film layer is controlled to be 2 μm; the thickness of the second enhanced silane film layer is controlled to be 3 μm.

[0045] Table 3 shows the implementation technical effects of the products obtained in Examples 1-10, and the adhesion of all film layers is tested according to ASTM D3359. After double-layer treatment, the corrosion resistance of the automotive sheet material is significantly improved, and it can pass the neutral salt spray test (NSS) for more than 240 hours without obvious corrosion.

[0046] Table 3 Implementation technical effects of the products obtained in Examples 1-10

[0047]

[0048] For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a multi-layer functionalized silane protective film on the surface of an automobile sheet. It is characterized in that The method comprises the following steps: ① Add the components of the first layer of base silane film into a stirring container in proportion, set the stirring temperature to 55°C to 65°C, the stirring speed to 400 to 600 rpm, and stir for 30 to 45 minutes to obtain a first layer of silane solution; ② Transfer the first layer of silane solution to the spraying equipment, adjust the spray gun to 25-30cm away from the plate, spray pressure 0.2-0.3MPa, and apply the first layer of silane solution on the surface of the plate; ③ Send the plate coated with the first layer of silane solution into the preheated drying room, control the drying temperature to 150℃~200℃, the drying time to 30~40 minutes, use the hot air circulation system to ensure uniform temperature distribution, and form the first layer of basic silane film; ④ Add the components of the second layer of enhanced silane film into the stirring container in proportion, set the stirring temperature to 55°C to 65°C, the stirring speed to 400 to 600 rpm, and stir for 30 to 45 minutes to obtain a second layer of silane solution; ⑤ Transfer the second layer of silane solution to the spraying equipment, adjust the spray gun to 25-30cm from the plate, spray pressure 0.2-0.3MPa, and apply the second layer of silane solution on the surface of the plate coated with the first layer of silane solution; ⑥ Send the plate coated with the second layer of silane solution into a preheated drying room at a drying temperature of 150°C to 200°C for 30 to 40 minutes. The second layer of enhanced silane film is completely cured to obtain a multi-layer functional silane protective film on the surface of the automotive plate.

2. The method according to claim 1, It is characterized in that The first basic silane film layer comprises the following components in parts by weight: 20-30 parts of a compound silane coupling agent, 1-4 parts of a catalyst, 5-10 parts of a cosolvent, 1-5 parts of a wetting agent, and 55-75 parts of deionized water; the compound silane coupling agent is prepared by mixing silane coupling agent KH-550 and silane coupling agent A-174 in a weight ratio of (2-3):1; the catalyst is prepared by mixing acetic acid with a concentration greater than 80% and hydrochloric acid with a concentration of 37% in a weight ratio of (2-3):1; the cosolvent is prepared by mixing ethanol and n-butanol in a weight ratio of (2-3):1; the wetting agent is prepared by mixing sodium dodecyl sulfate and a non-ionic surfactant Tween 80 in a weight ratio of 1:

1.

3. The method according to claim 1, It is characterized in that The second enhanced silane film layer comprises the following components in parts by weight: 20 to 30 parts of a compound silane coupling agent, 1 to 5 parts of a catalyst, 5 to 10 parts of a cosolvent, 1 to 5 parts of a reinforcing agent, and 55 to 75 parts of deionized water; the compound silane coupling agent is prepared by mixing a silane coupling agent KH-560 and a silane coupling agent GPTMS in a weight ratio of (3 to 4):1; the catalyst is prepared by mixing a 98.3% sulfuric acid and a 55% nitric acid in a weight ratio of (2 to 3):1; the cosolvent is prepared by mixing a methanol and an ethylene glycol in a weight ratio of (1 to 2):1; the reinforcing agent is prepared by mixing a nano-silicon dioxide and a nano-alumina with a size of 30 to 50 nm in a weight ratio of 1:

1.

4. The method according to claim 1, It is characterized in that The thickness of the first basic silane film layer is controlled to be 1-2 μm.

5. The method according to claim 1, It is characterized in that The thickness of the second enhanced silane film layer is controlled to be 2-3 μm.

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