A method for removing an acrylic coating from a metal surface

Abstract

The application provides a method for removing an acrylic coating on a metal surface. The method comprises the following steps: S1, mixing N-methyl pyrrolidone 50-70%, dimethylbenzene 10-20%, ethyl acetate 10-20% and the rest water, stirring uniformly to obtain a solution; S2, cleaning and blowing dry a sample with an acrylic coating to obtain a sample to be cleaned; S3, placing the sample to be cleaned in a fumigation machine, fumigating at 80-100 DEG C for 25-45 min, cooling and taking out; and S4, cleaning and blowing dry to obtain a sample without the coating. The sample to be cleaned is contacted with the steam of the fumigation solution by using the fumigation method, and under the high temperature and the dissolving effect of the steam, the acrylic coating is separated from the sample matrix; the method for removing the acrylic coating has the advantages of small fumigation solution consumption, low cost, high removal efficiency, good cleaning effect, low toxicity, environmental friendliness, completion in a closed system and full protection of the health of the operators.

Description

Technical Field

[0001] This invention relates to the technical field of industrial paint stripping, and in particular to a method for removing acrylic coatings from metal surfaces. Background Technology

[0002] Surface coating is a crucial step in modern product manufacturing. It forms a surface coating on the product, providing protection against rust and corrosion. However, products are subject to external factors during use, such as corrosive media in harsh environments, causing varying degrees of damage to the coating. In such cases, coating repair is necessary. Coating repair involves removing the old coating and applying a new one. Furthermore, some imperfections are unavoidable during the coating process; these also require surface coating removal and recoating. Therefore, surface coating removal is a critical step in product manufacturing and maintenance, as the thoroughness of surface coating removal directly impacts the performance of the subsequent new coating.

[0003] In existing technologies, there are many methods for removing surface coatings from products, which can be broadly classified into two categories: physical release methods and chemical release methods. Physical release methods use sandpaper or similar materials to polish the sample surface, thereby removing the coating. This method removes the coating relatively cleanly and thoroughly; however, it easily damages the sample substrate, can only perform large-scale release, and the degree of release is difficult to control. Chemical release methods involve immersing the sample to be cleaned in a chemical reagent. By changing the immersion temperature, immersion time, amount of chemical reagent, and the chemical reagent ratio, the surface coating dissolves in the chemical reagent, thus removing the original coating from the sample surface. This method is convenient to operate and causes minimal damage to the sample substrate, making it the most commonly used method.

[0004] Chemical release methods require complete immersion of the sample in chemical reagents, resulting in high reagent consumption, especially for cleaning surface coatings on large samples, leading to high costs. Furthermore, these chemicals need to be in contact with the sample for a considerable period to dissolve and remove the coating, resulting in low removal efficiency. Additionally, these chemicals are often volatile and toxic, causing environmental pollution and harming the health of operators. Therefore, there is an urgent need for a low-cost, convenient, fast, efficient, environmentally friendly method for removing metal surface coatings that poses no harm to operator health. Summary of the Invention

[0005] The purpose of this invention is to provide a method for removing acrylic coatings from metal surfaces, aiming to solve the problems of existing chemical release methods for removing coatings from sample surfaces, such as large amounts of chemical reagents, high costs, low removal efficiency, easy environmental pollution, and harm to the health of operators.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is implemented as follows:

[0007] The present invention provides a method for removing acrylic coatings from a metal surface, comprising the following steps:

[0008] Preparation of S1 solution

[0009] 1) Measure the following raw materials in volume percentage as follows: N-methylpyrrolidone 50-70%, xylene 10-20%, ethyl acetate 10-20%, and the remainder is water;

[0010] 2) Add water, ethyl acetate and xylene to N-methylpyrrolidone in sequence, stir well to obtain a solution;

[0011] S2 Sample Pretreatment

[0012] 3) Take a sample with an acrylic coating on its surface, clean it with water and anhydrous ethanol in sequence, blow it dry, and obtain the sample to be cleaned for later use;

[0013] S3 sample fumigation

[0014] 4) Take the fumigation machine. The fumigation machine includes a base and a fumigation chamber. The fumigation chamber is set on top of the base and covers the base. The fumigation chamber is used to form a closed space above the base. The top of the base is provided with a solution pool. The outside of the solution pool is provided with a jacket. The jacket is provided with heating oil. The heating oil is connected to a heater.

[0015] 5) Place the sample to be cleaned obtained in step 3) into the fumigation machine, suspend the sample above the solution tank, add the solution obtained in step 2) into the solution tank, start the heater, heat the solution to 80-100℃, fumigate for 25-45 minutes, turn off the heater, cool, and take out to obtain the pre-treated sample.

[0016] S4 Sample Post-processing

[0017] 6) The sample obtained in step 5) is washed with water and anhydrous ethanol in sequence, and then dried to obtain an uncoated sample.

[0018] This invention uses N-methylpyrrolidone as a solvent, adding xylene, ethyl acetate, and water to N-methylpyrrolidone and stirring until homogeneous to prepare a fumigation solution. The sample to be cleaned is brought into contact with the steam of the fumigation solution. Under the high temperature and dissolving effect of the steam, the adhesion between the acrylic coating and the sample substrate is continuously reduced, thereby removing the acrylic coating. This method of removing acrylic coatings uses a small amount of fumigation solution, is low in cost, has high removal efficiency, low toxicity, is environmentally friendly, easy to operate, has good sealing properties, fully protects the health of operators, and is non-corrosive to the sample substrate. It has excellent cleaning effect and can be applied to large-scale production.

[0019] In a preferred embodiment, in step 1), the following raw materials are measured in volume percentages: 50-60% N-methylpyrrolidone, 15-20% xylene, 15-20% ethyl acetate, and the remainder is water. The fumigation solution of this invention is developed for acrylic coatings on sample surfaces. N-methylpyrrolidone has good solubility, is miscible with water in any proportion, and is soluble in ether, acetone, esters, halogenated hydrocarbons, aromatic hydrocarbons, and various other organic solvents, mixing almost completely with all solvents. Xylene, ethyl acetate, and water can all easily dissolve in N-methylpyrrolidone. Xylene, ethyl acetate, water, and N-methylpyrrolidone mutually promote and complement each other, forming a homogeneous fumigation solution. Moreover, these four substances have similar boiling points; upon heating, they simultaneously form steam. The high-temperature steam interacts strongly with the acrylic coating, thereby quickly and effectively removing the acrylic coating from the metal surface.

[0020] In a preferred embodiment, the water in the raw material is deionized water. Deionized water does not contain impurities in ionic form, and using deionized water to prepare the fumigation solution will not affect the fumigation solution. The steam from the fumigation solution can be recycled after condensation.

[0021] In a preferred embodiment, in step 5), the distance between the sample to be cleaned and the surface of the solution in the solution tank is 5-10 cm. The closer the sample to the solution tank, the higher the steam temperature and the faster the removal efficiency of the acrylic coating. The distance between the sample to be cleaned and the surface of the solution in the solution tank can be determined according to the actual situation.

[0022] In a preferred embodiment, during step 5), the cooling temperature is lowered to below 60°C. After fumigation, the heater is turned off, and the sample is cooled. First, the fumigation steam in the fumigation chamber condenses, preventing steam leakage during the removal of the pre-treated sample, thus protecting the environment and the health of the operators. Simultaneously, the pre-treated sample is cooled, facilitating its removal and subsequent processing.

[0023] In a preferred embodiment, during step 5), the cooling temperature is set to 50-60°C. Cooling is performed within a fumigation chamber. The purpose of cooling is to lower the temperature of the pre-treated sample, ensuring it maintains good performance during post-treatment and avoiding sudden heating and cooling. Simultaneously, it also facilitates the removal of the acrylic coating from the surface of the pre-treated sample.

[0024] In a preferred embodiment, in step 5), the solution is heated to 85-95°C, and the fumigation time is 30-40 minutes. The fumigation solution is heated and evaporates in the fumigation chamber to form fumigation steam. The acrylic coating can be successfully peeled off without the fumigation solution temperature being too high, resulting in low energy consumption.

[0025] In a preferred embodiment, in step 3), the sample is rinsed with water 1-3 times and with anhydrous ethanol 1-3 times. The sample to be cleaned only requires rinsing with water and anhydrous ethanol, without any additional treatment. Water rinsing removes dust from the sample surface, while anhydrous ethanol rinsing removes oil stains from the sample surface, preventing dust and oil from contaminating the fumigation solution and thus improving fumigation efficiency.

[0026] As a preferred embodiment, in step 3), water rinsing is ultrasonic cleaning, and anhydrous ethanol rinsing is also ultrasonic cleaning. Ultrasonic cleaning has good cleaning effect, fast speed, convenient operation, and is easy to implement.

[0027] In a preferred embodiment, in step 6), the sample is rinsed with water 3-5 times and then with anhydrous ethanol 3-5 times. The purpose of rinsing with water is to remove the acrylic coating adhering to the surface of the initially treated sample, and the purpose of rinsing with anhydrous ethanol is to further remove the fumigation solution adhering to the surface of the sample, thereby obtaining a clean sample for subsequent recoating.

[0028] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention uses N-methylpyrrolidone as a solvent, and adds xylene, ethyl acetate, and water to N-methylpyrrolidone to promote and complement each other, forming a homogeneous fumigation solution. Using the fumigation method, the sample to be cleaned comes into contact with the steam of the fumigation solution. Under the high temperature and dissolving effect of the steam, the adhesion between the acrylic coating and the sample substrate continuously decreases, thereby removing the acrylic coating. This method of removing acrylic coatings uses a small amount of fumigation solution, is low in cost, has high removal efficiency, low toxicity, is environmentally friendly, easy to operate, has good sealing properties, fully protects the health of operators, and is non-corrosive to the sample substrate. It has a good cleaning effect and can be applied to large-scale production. Attached Figure Description

[0029] Figure 1 A three-dimensional structural schematic diagram of a fumigation machine used in an embodiment of the method for removing acrylic coatings from metal surfaces provided by the present invention;

[0030] Figure 2 for Figure 1 A schematic diagram of the three-dimensional structure after removing the fumigation chamber;

[0031] Figure 3 This is a scanning electron microscope image of the uncoated sample obtained in Embodiment 1 of the present invention;

[0032] Figure 4 This is a scanning electron microscope image of the uncoated sample obtained in Embodiment 2 of the present invention;

[0033] Figure 5 This is a scanning electron microscope image of the uncoated sample obtained in Embodiment 3 of the present invention;

[0034] Figure 6 This is a scanning electron microscope image of the control sample 1 of the present invention;

[0035] Figure 7 This is a scanning electron microscope image of the control sample 2 of this invention;

[0036] Figure 8 This is a scanning electron microscope image of control sample three of the present invention;

[0037] Figure 9 This is a scanning electron microscope image of the control sample four of this invention;

[0038] Figure 10 This is a scanning electron microscope image of control sample five of the present invention;

[0039] In the diagram: 10-base; 20-fumigation chamber; 21-solution pool; 22-sample to be cleaned. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The present invention provides a method for removing acrylic coatings from a metal surface, comprising the following steps:

[0042] Preparation of S1 solution

[0043] 1) Measure the following raw materials in volume percentage as follows: N-methylpyrrolidone 50-70%, xylene 10-20%, ethyl acetate 10-20%, and the remainder is water;

[0044] 2) Add water, ethyl acetate and xylene to N-methylpyrrolidone in sequence, stir well to obtain a solution;

[0045] S2 Sample Pretreatment

[0046] 3) Take a sample with an acrylic coating on its surface, clean it with water and anhydrous ethanol in sequence, blow it dry, and obtain the sample to be cleaned for later use;

[0047] S3 sample fumigation

[0048] 4) Take the fumigation machine, see attached document. Figure 1 and attached Figure 2 The fumigation machine includes a base 10 and a fumigation chamber 20. The fumigation chamber 20 is located on top of the base 10 and covers the base 10. The fumigation chamber 20 is used to form a closed space above the base 10. The top of the base 10 is provided with a solution pool 21. The outside of the solution pool 21 is provided with a jacket. The jacket is provided with heating oil, and the heating oil is connected to a heater.

[0049] 5) Place the sample 22 to be cleaned obtained in step 3) into the fumigation machine, so that the sample 22 to be cleaned is suspended above the solution tank 21. Add the solution obtained in step 2) into the solution tank 21, start the heater, and heat the solution to 80-100℃. Fumigate for 25-45 minutes, turn off the heater, cool, and take out to obtain the pre-treated sample.

[0050] S4 Sample Post-processing

[0051] 6) The sample obtained in step 5) is washed with water and anhydrous ethanol in sequence, and then dried to obtain an uncoated sample.

[0052] Preferably, in step 1), the following raw materials in volume percentage are measured sequentially: 50-60% N-methylpyrrolidone, 15-20% xylene, 15-20% ethyl acetate, and the remainder is water.

[0053] Preferably, the water in the raw material is deionized water.

[0054] Preferably, in step 5), the distance between the sample to be cleaned and the surface of the solution in the solution pool is 5-10 cm.

[0055] Preferably, in step 5), the cooling temperature is below 60°C.

[0056] Furthermore, in step 5), during cooling, the temperature is reduced to 50-60°C.

[0057] Preferably, in step 5), the solution is heated to 85-95°C and the fumigation time is 30-40 minutes.

[0058] Preferably, in step 3), the water is rinsed 1-3 times and the anhydrous ethanol is rinsed 1-3 times.

[0059] Preferably, in step 3), water cleaning is ultrasonic cleaning, and anhydrous ethanol cleaning is also ultrasonic cleaning.

[0060] Preferably, in step 6), the water is rinsed 3-5 times and the anhydrous ethanol is rinsed 3-5 times.

[0061] Example 1

[0062] The present invention provides a method for removing acrylic coatings from a metal surface, comprising the following steps:

[0063] Preparation of S1 solution

[0064] 1) Measure the following raw materials in volume percentages in sequence: N-methylpyrrolidone 70%, xylene 10%, ethyl acetate 10%, deionized water 10%;

[0065] 2) Add deionized water, ethyl acetate and xylene to N-methylpyrrolidone in sequence, stir well to obtain a solution;

[0066] S2 Sample Pretreatment

[0067] 3) Take a sample with an acrylic coating on its surface, wash it once with water, and then wash it three times with anhydrous ethanol until the surface is clean and free of stains. Dry it with a water blower to obtain the sample to be cleaned and set it aside.

[0068] S3 sample fumigation

[0069] 4) Take the fumigation machine. The fumigation machine includes a base and a fumigation chamber. The fumigation chamber is set on top of the base and covers the base. The fumigation chamber is used to form a closed space above the base. The top of the base is provided with a solution pool. The outside of the solution pool is provided with a jacket. The jacket is provided with heating oil. The heating oil is connected to a heater.

[0070] 5) Place the sample to be cleaned obtained in step 3) in the fumigation machine, suspending the sample above the solution tank. Add the solution obtained in step 2) into the solution tank. The distance between the sample to be cleaned and the solution surface in the solution tank should be 5 cm. Start the heater to raise the temperature of the solution to 80°C. The surface of the sample to be cleaned is fumigated with mixed steam for 45 minutes. The adhesion between the acrylic coating and the sample substrate reaches its worst state. Turn off the heater, cool to 60°C, and take it out to obtain the pre-treated sample.

[0071] S4 Sample Post-processing

[0072] 6) The sample obtained in step 5) was washed with water 3 times, washed with anhydrous ethanol 3 times, and dried with a hair dryer to obtain an uncoated sample.

[0073] Example 2

[0074] The present invention provides a method for removing acrylic coatings from a metal surface, comprising the following steps:

[0075] Preparation of S1 solution

[0076] 1) Measure the following raw materials in volume percentages in sequence: N-methylpyrrolidone 50%, xylene 20%, ethyl acetate 20%, deionized water 10%;

[0077] 2) Add deionized water, ethyl acetate and xylene to N-methylpyrrolidone in sequence, stir well to obtain a solution;

[0078] S2 Sample Pretreatment

[0079] 3) Take a sample with an acrylic coating on its surface, clean it with water three times and with anhydrous ethanol three times to make its surface clean and free of stains. Dry it with a hair dryer to obtain the sample to be cleaned and set aside.

[0080] S3 sample fumigation

[0081] 4) Take the fumigation machine. The fumigation machine includes a base and a fumigation chamber. The fumigation chamber is set on top of the base and covers the base. The fumigation chamber is used to form a closed space above the base. The top of the base is provided with a solution pool. The outside of the solution pool is provided with a jacket. The jacket is provided with heating oil. The heating oil is connected to a heater.

[0082] 5) Place the sample to be cleaned obtained in step 3) in the fumigation machine, suspending the sample above the solution tank. Add the solution obtained in step 2) into the solution tank. The distance between the sample to be cleaned and the solution surface in the solution tank should be 8 cm. Start the heater to raise the temperature of the solution to 90°C. The surface of the sample to be cleaned is fumigated with mixed steam for 30 minutes. The adhesion between the acrylic coating and the sample substrate reaches its worst state. Turn off the heater and cool it down to 55°C. Take it out to obtain the pre-treated sample.

[0083] S4 Sample Post-processing

[0084] 6) The sample obtained in step 5) was washed with water 5 times, washed with anhydrous ethanol 3 times, and dried with a hair dryer to obtain an uncoated sample.

[0085] Example 3

[0086] The present invention provides a method for removing acrylic coatings from a metal surface, comprising the following steps:

[0087] Preparation of S1 solution

[0088] 1) Measure the following raw materials in volume percentages in sequence: N-methylpyrrolidone 60%, xylene 15%, ethyl acetate 15%, deionized water 10%;

[0089] 2) Add deionized water, ethyl acetate and xylene to N-methylpyrrolidone in sequence, stir well to obtain a solution;

[0090] S2 Sample Pretreatment

[0091] 3) Take a sample with an acrylic coating on its surface, clean it with water ultrasonically 3 times, and clean it with anhydrous ethanol ultrasonically once to make its surface clean and free of stains. Dry it with a hair dryer to obtain the sample to be cleaned and set aside.

[0092] S3 sample fumigation

[0093] 4) Take the fumigation machine. The fumigation machine includes a base and a fumigation chamber. The fumigation chamber is set on top of the base and covers the base. The fumigation chamber is used to form a closed space above the base. The top of the base is provided with a solution pool. The outside of the solution pool is provided with a jacket. The jacket is provided with heating oil. The heating oil is connected to a heater.

[0094] 5) Place the sample to be cleaned obtained in step 3) in the fumigation machine, suspending the sample above the solution tank. Add the solution obtained in step 2) into the solution tank. The distance between the sample to be cleaned and the solution surface in the solution tank should be 10 cm. Start the heater to heat the solution to 100°C. The surface of the sample to be cleaned is fumigated with mixed steam for 25 minutes. The adhesion between the acrylic coating and the sample substrate reaches its worst state. Turn off the heater and cool it to 50°C. Take it out to obtain the pre-treated sample.

[0095] S4 Sample Post-processing

[0096] 6) The sample obtained in step 5) was washed with water 3 times, washed with anhydrous ethanol 5 times, and dried with a hair dryer to obtain an uncoated sample.

[0097] Comparative Example 1

[0098] A method for removing an acrylic coating from a metal surface includes the following steps:

[0099] Preparation of S1 solution

[0100] 1) Measure the following raw materials in volume percentages in sequence: N-methylpyrrolidone 55.5%, xylene 22.2%, ethyl acetate 22.3%;

[0101] 2) Add ethyl acetate and xylene sequentially to N-methylpyrrolidone, stir until homogeneous, and obtain a solution;

[0102] S2 Sample Pretreatment

[0103] 3) Take a sample with an acrylic coating on its surface, clean it with water three times and with anhydrous ethanol three times to make its surface clean and free of stains. Dry it with a hair dryer to obtain the sample to be cleaned and set aside.

[0104] S3 sample fumigation

[0105] 4) Take the fumigation machine. The fumigation machine includes a base and a fumigation chamber. The fumigation chamber is set on top of the base and covers the base. The fumigation chamber is used to form a closed space above the base. The top of the base is provided with a solution pool. The outside of the solution pool is provided with a jacket. The jacket is provided with heating oil. The heating oil is connected to a heater.

[0106] 5) Place the sample to be cleaned obtained in step 3) into the fumigation machine, so that the sample to be cleaned is suspended above the solution tank. Add the solution obtained in step 2) into the solution tank. The distance between the sample to be cleaned and the solution surface in the solution tank is 8cm. Start the heater to raise the temperature of the solution to 90℃, fumigate for 60min, turn off the heater, cool down to 55℃, take it out, and obtain the pre-treated sample.

[0107] S4 Sample Post-processing

[0108] 6) The sample obtained in step 5) was washed with water 5 times, washed with anhydrous ethanol 5 times, and dried with a hair dryer to obtain an uncoated sample, i.e., control sample one.

[0109] Comparative Example 2

[0110] A method for removing an acrylic coating from a metal surface includes the following steps:

[0111] Preparation of S1 solution

[0112] 1) Measure the following raw materials in volume percentages in sequence: N-methylpyrrolidone 62.5%, ethyl acetate 25.0%, and deionized water 12.5%;

[0113] 2) Add deionized water and ethyl acetate to N-methylpyrrolidone in sequence, stir until homogeneous, and obtain a solution;

[0114] S2 Sample Pretreatment

[0115] 3) Take a sample with an acrylic coating on its surface, clean it with water three times and with anhydrous ethanol three times to make its surface clean and free of stains. Dry it with a hair dryer to obtain the sample to be cleaned and set aside.

[0116] S3 sample fumigation

[0117] 4) Take the fumigation machine. The fumigation machine includes a base and a fumigation chamber. The fumigation chamber is set on top of the base and covers the base. The fumigation chamber is used to form a closed space above the base. The top of the base is provided with a solution pool. The outside of the solution pool is provided with a jacket. The jacket is provided with heating oil. The heating oil is connected to a heater.

[0118] 5) Place the sample to be cleaned obtained in step 3) into the fumigation machine, so that the sample to be cleaned is suspended above the solution tank. Add the solution obtained in step 2) into the solution tank. The distance between the sample to be cleaned and the solution surface in the solution tank is 8cm. Start the heater to raise the temperature of the solution to 90℃, fumigate for 60min, turn off the heater, cool down to 55℃, take it out, and obtain the pre-treated sample.

[0119] S4 Sample Post-processing

[0120] 6) The sample obtained in step 5) was washed with water 5 times, washed with anhydrous ethanol 5 times, and dried with a hair dryer to obtain an uncoated sample, i.e., control sample 2.

[0121] Comparative Example 3

[0122] A method for removing an acrylic coating from a metal surface includes the following steps:

[0123] Preparation of S1 solution

[0124] 1) Measure the following raw materials in volume percentages in sequence: N-methylpyrrolidone 55.5%, xylene 22.2%, deionized water 22.3%;

[0125] 2) Add deionized water and xylene to N-methylpyrrolidone in sequence, stir well to obtain a solution;

[0126] S2 Sample Pretreatment

[0127] 3) Take a sample with an acrylic coating on its surface, clean it with water three times and with anhydrous ethanol three times to make its surface clean and free of stains. Dry it with a hair dryer to obtain the sample to be cleaned and set aside.

[0128] S3 sample fumigation

[0129] 4) Take the fumigation machine. The fumigation machine includes a base and a fumigation chamber. The fumigation chamber is set on top of the base and covers the base. The fumigation chamber is used to form a closed space above the base. The top of the base is provided with a solution pool. The outside of the solution pool is provided with a jacket. The jacket is provided with heating oil. The heating oil is connected to a heater.

[0130] 5) Place the sample to be cleaned obtained in step 3) into the fumigation machine, so that the sample to be cleaned is suspended above the solution tank. Add the solution obtained in step 2) into the solution tank. The distance between the sample to be cleaned and the solution surface in the solution tank is 8cm. Start the heater to raise the temperature of the solution to 90℃, fumigate for 60min, turn off the heater, cool down to 55℃, take it out, and obtain the pre-treated sample.

[0131] S4 Sample Post-processing

[0132] 6) The sample obtained in step 5) was washed with water 5 times, washed with anhydrous ethanol 5 times, and dried with a hair dryer to obtain an uncoated sample, i.e., control sample three.

[0133] Comparative Example 4

[0134] A method for removing an acrylic coating from a metal surface includes the following steps:

[0135] Preparation of S1 solution

[0136] 1) Measure the following raw materials in volume percentages in sequence: N-methylpyrrolidone 50%, xylene 20%, ethyl acetate 20%, deionized water 10%;

[0137] 2) Add deionized water, ethyl acetate and xylene to N-methylpyrrolidone in sequence, stir well to obtain a solution;

[0138] S2 Sample Pretreatment

[0139] 3) Take a sample with an acrylic coating on its surface, clean it with water three times and with anhydrous ethanol three times to make its surface clean and free of stains. Dry it with a hair dryer to obtain the sample to be cleaned and set aside.

[0140] S3 coating removal

[0141] 4) Place the sample to be cleaned obtained in step 3) into the solution obtained in step 2), heat the solution to 90°C, soak for 60 minutes, turn off the heater, take it out, and obtain the pre-treated sample.

[0142] S4 Sample Post-processing

[0143] 5) The sample obtained in step 4) was washed with water 5 times, washed with anhydrous ethanol 5 times, and dried with a hair dryer to obtain an uncoated sample, i.e., control sample four.

[0144] Comparative Example 5

[0145] A method for removing an acrylic coating from a metal surface includes the following steps:

[0146] Preparation of S1 solution

[0147] 1) Measure the following raw materials in volume percentages in sequence: N-methylpyrrolidone 30%, xylene 30%, ethyl acetate 30%, deionized water 10%;

[0148] 2) Add deionized water, ethyl acetate and xylene to N-methylpyrrolidone in sequence, stir well to obtain a mixture;

[0149] S2 Sample Pretreatment

[0150] 3) Take a sample with an acrylic coating on its surface, clean it with water three times and with anhydrous ethanol three times to make its surface clean and free of stains. Dry it with a hair dryer to obtain the sample to be cleaned and set aside.

[0151] S3 sample fumigation

[0152] 4) Take the fumigation machine. The fumigation machine includes a base and a fumigation chamber. The fumigation chamber is set on top of the base and covers the base. The fumigation chamber is used to form a closed space above the base. The top of the base is provided with a solution pool. The outside of the solution pool is provided with a jacket. The jacket is provided with heating oil. The heating oil is connected to a heater.

[0153] 5) Place the sample to be cleaned obtained in step 3) in the fumigation machine, so that the sample to be cleaned is suspended above the solution tank. Add the mixture obtained in step 2) into the solution tank. The distance between the sample to be cleaned and the surface of the mixture in the solution tank is 8cm. Start the heater to raise the temperature of the mixture to 90℃, fumigate for 30min, turn off the heater, cool it down to 55℃, take it out, and obtain the pre-treated sample.

[0154] S4 Sample Post-processing

[0155] 6) The sample obtained in step 5) was washed with water 5 times, washed with anhydrous ethanol 3 times, and dried with a hair dryer to obtain an uncoated sample, i.e., control sample five.

[0156] The three uncoated samples obtained in Examples 1 to 3, and the control samples 1 to 5 obtained in Comparative Examples 1 to 5, were observed under a Hitachi Regulus 8100 scanning electron microscope. Figure 3 To be continued Figure 5 It can be seen that the samples treated using the method of this invention have no acrylic coating on their surface, and the sample surfaces are smooth and free of foreign matter. However, due to the attached... Figure 6 Appendix Figure 7 and attached Figure 8 It can be seen that all three control samples (sample 1, sample 2, and sample 3) have varying degrees of acrylic coating adhering to their surfaces, resulting in rough surfaces. Figure 9As can be seen, due to the immersion method used, the removal of the acrylic coating in control sample four was very ineffective. A large amount of residual acrylic coating remained on the sample surface; these residual coatings were very small, difficult to observe with the naked eye, and difficult to clean. Figure 10 It can be seen that due to the unreasonable formulation design of the fumigation solution, the control sample 5 also had a poor effect on removing the acrylic coating. A large amount of residual coating was attached to the sample surface. These residual acrylic coatings were very small and difficult to observe with the naked eye, making them difficult to clean.

[0157] Therefore, compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses N-methylpyrrolidone as a solvent, and adds xylene, ethyl acetate and water to N-methylpyrrolidone to promote and complement each other, forming a homogeneous fumigation solution. Using the fumigation method, the sample to be cleaned comes into contact with the steam of the fumigation solution. Under the high temperature and dissolving effect of the steam, the adhesion between the acrylic coating and the sample substrate is continuously reduced, thereby removing the acrylic coating. This method of removing acrylic coatings uses less fumigation solution, has low cost, high removal efficiency, low toxicity, is environmentally friendly, easy to operate, has good sealing performance, fully protects the health of operators, and is non-corrosive to the sample substrate. It has a good cleaning effect and can be applied to large-scale production.

[0158] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for removing an acrylic coating from a metal surface, characterized in that, Comprising the following steps: S1 solution preparation Step 1) sequentially take the following volume percentage of raw materials: N-methyl pyrrolidone 50-70%, xylene 10-20%, ethyl acetate 10-20%, the rest is water; Step 2) add water, ethyl acetate and xylene to N-methyl pyrrolidone in turn, stir evenly, get the solution; S2 sample pretreatment Step 3) take the sample with acrylic coating on the surface, wash with water and anhydrous ethanol in turn, dry, get the sample to be cleaned, ready for use; S3 sample fumigation Step 4) take the fumigation machine, the fumigation machine includes base and fumigation chamber, the fumigation chamber is arranged on the top of the base and is buckled on the base, the fumigation chamber is used to form a closed space above the base, the top of the base is provided with a solution pool, the outside of the solution pool is provided with a jacket, the jacket is provided with heating oil, the heating oil is connected with a heater; Step 5) place the sample to be cleaned obtained in step 3) in the fumigation machine, hang the sample to be cleaned above the solution pool, add the solution obtained in step 2) to the solution pool, start the heater, heat the solution to 80-100℃, fumigate for 25-45min, turn off the heater, cool down, take out, get the preliminary treated sample; S4 sample post-treatment Step 6) wash the preliminary treated sample obtained in step 5) with water and anhydrous ethanol in turn, dry, get the sample without coating.

2. The method for removing acrylic coating on the surface of metal according to claim 1, characterized in that: In step 1), the following volume percentage of raw materials is sequentially taken: N-methyl pyrrolidone 50-60%, xylene 15-20%, ethyl acetate 15-20%, the rest is water.

3. The method for removing acrylic coating on the surface of metal according to claim 1 or 2, characterized in that: The water in the raw materials is deionized water.

4. The method for removing acrylic coating on the surface of metal according to claim 1, characterized in that: In step 5), the distance from the sample to be cleaned to the surface of the solution in the solution pool is 5-10cm.

5. The method for removing acrylic coating on the surface of metal according to claim 1, characterized in that: In step 5), when cooling, cool down to below 60℃.

6. The method for removing acrylic coating on the surface of metal according to claim 5, characterized in that: In step 5), when cooling, cool down to 50-60℃.

7. The method for removing acrylic coating on the surface of metal according to claim 1, characterized in that: In step 5), heat the solution to 85-95℃, and the fumigation time is 30-40min.

8. The method for removing acrylic coating on the surface of metal according to claim 1, characterized in that: In step 3), wash with water 1-3 times, and wash with anhydrous ethanol 1-3 times.

9. The method for removing acrylic coating on the surface of metal according to claim 8, characterized in that: In step 3), the water washing is ultrasonic cleaning, and the anhydrous ethanol washing is also ultrasonic cleaning.

10. The method for removing acrylic coating on the surface of metal according to claim 1, characterized in that: In step 6), the product is washed with water 3-5 times and with anhydrous ethanol 3-5 times. In step 6), the product is washed with water 3-5 times and with anhydrous ethanol 3-5 times.

Images