A paint remover, a paint removal method and its application

Abstract

The application discloses a paint remover, a paint removing method and application thereof, and belongs to the technical field of paint film removal. The paint remover provided by the application comprises the following components in mass fraction: 3-10 parts of an ester compound, 0.3-1.5 parts of an emulsifier and 88-97 parts of water. The structural formula of the ester compound is R1COOR2, wherein R1 is an alkyl or alkenyl group with 1-5 carbon atoms, and R2 is an alkyl group with 3-4 carbon atoms. The emulsifier is a non-ionic emulsifier and / or an anionic emulsifier. The paint remover provided by the application has a good paint film removal rate. Meanwhile, the paint remover formula provided by the application has no damage to the material after paint removal, and the material after paint film removal can be recycled and utilized in high quality. Furthermore, the mass percentage of water in the paint remover provided by the application is more than 85%, namely, the overall paint remover formula is environment-friendly and non-toxic, and meets the green environmental protection requirement.

Description

Technical Field

[0001] This invention belongs to the field of paint film removal technology, and particularly relates to a paint remover, a paint removal method, and its application. Background Technology

[0002] With rapid economic development, automobiles are widely used in daily life, leading to an increasing number of scrapped vehicles, especially car parts (bumpers). Currently, scrap bumpers are mainly recycled through simple direct granulation, which does not completely remove the paint and other components from their surface, resulting in only low-level recycling. A few methods use shot blasting machines for simple physical polishing to remove the paint layer, but this method causes significant environmental pollution (generating a large amount of dust), has low efficiency, and cannot be mass-produced. Traditional chemical recycling methods use organic solvents such as benzyl alcohol, xylene, and chloroform to remove the paint film, but this method causes significant environmental pollution, harm to human health, and severe damage to materials, making it impossible to reuse the removed paint film efficiently. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a paint remover, paint removal method and its application that have excellent paint removal efficiency and do not damage the substrate material.

[0004] To achieve the above objectives, in a first aspect, the present invention provides a paint remover comprising the following components in parts by weight: 3-10 parts of an ester compound, 0.3-1.5 parts of an emulsifier, and 88-97 parts of water; wherein the ester compound has the structural formula R1COOR2, wherein R1 is an alkyl or alkenyl group having 1-5 carbon atoms, and R2 is an alkyl group having 3-4 carbon atoms; and the emulsifier is a nonionic emulsifier and / or an anionic emulsifier.

[0005] The paint remover provided by this invention achieves a good paint film removal rate of over 90% through the combined action of specific ester compounds and emulsifiers. Furthermore, the paint remover formulation provided by this invention does not damage the substrate material after paint removal, and the material after paint film removal can be recycled with high quality. At the same time, the water content in the paint remover provided by this invention is over 85%, that is, the solvent content is low, and the overall paint remover formulation is environmentally friendly and non-toxic, meeting the requirements of green environmental protection.

[0006] As a preferred embodiment of the paint remover of the present invention, the paint remover comprises the following components in parts by weight: 5-8 parts of ester compound and 0.5-1.2 parts of emulsifier.

[0007] The inventors discovered that when the mass fractions of ester compounds and emulsifiers are further optimized to be within the above-mentioned range, the resulting paint remover achieves a higher paint removal rate and causes less damage to the material after paint removal when the same method is used to remove the paint film.

[0008] As a preferred embodiment of the paint remover of the present invention, at least one of the following (a)-(d) is used:

[0009] (a) R1 is any one of ethyl, propenyl, methacryl, and ethylpropenyl;

[0010] (b) R2 is isopropyl or butyl;

[0011] (c) The nonionic emulsifier is at least one of fatty alcohol polyoxyethylene ether (AE09), octylphenol polyoxyethylene ether (OP-10), and hydroxyethyl cellulose (HEC);

[0012] (d) The anionic emulsifier is at least one of sodium dodecylbenzenesulfonate (LAS), disodium sulfosuccinate monoester (MES), sodium dodecyl sulfate (K-12), and oleyl alcohol polyether (OV-10).

[0013] Depending on the selection of R1 and R2, the ester substance may, for example, be isopropyl acetate, butyl acetate, isopropyl acrylate, butyl acrylate, isopropyl methacrylate, butyl methacrylate, isopropyl ethyl acrylate, or butyl ethyl acrylate.

[0014] In a preferred embodiment of the paint remover of the present invention, the ester compound is at least one selected from isopropyl acetate, butyl acetate, butyl acrylate, and butyl methacrylate.

[0015] In a preferred embodiment of the paint remover of the present invention, the ester compound contains 70-90% by mass of butyl acetate.

[0016] For example, the ester compound is a mixture of butyl acetate and isopropyl acetate, wherein the mass percentage of butyl acetate in the ester compound can be 70%, 75%, 80%, 85%, or 90%; the ester compound is a mixture of butyl acetate and butyl acrylate, wherein the mass percentage of butyl acetate in the ester compound can be 70%, 75%, 80%, 85%, or 90%; the ester compound is a mixture of butyl acetate and butyl methacrylate, wherein the mass percentage of butyl acetate in the ester compound can be 70%, 75%, 80%, 85%, or 90%.

[0017] Preferably, the ester compound is a mixture of butyl acetate and isopropyl acetate, butyl acrylate, or butyl methacrylate.

[0018] The inventors discovered that when the ester compound is further selected as a mixture of butyl acetate and other esters, and the mass percentage of butyl acetate in the ester compound is limited to 70-90%, not only is the initial paint film removal rate high, but the paint remover can also be reused, with a paint removal rate of over 80% obtained in the second cycle.

[0019] In a preferred embodiment of the paint remover of the present invention, the emulsifier is at least one of disodium sulfosuccinate monoester, sodium dodecylbenzenesulfonate, fatty alcohol polyoxyethylene ether, and hydroxyethyl cellulose.

[0020] In a preferred embodiment of the paint remover of the present invention, the mass percentage of disodium sulfosuccinate monoester in the emulsifier is 30-50%.

[0021] For example, the emulsifier is a mixture of disodium sulfosuccinate and sodium dodecylbenzenesulfonate, wherein the mass percentage of disodium sulfosuccinate in the emulsifier can be 30%, 35%, 40%, 45%, or 50%; the emulsifier is a mixture of disodium sulfosuccinate and fatty alcohol polyoxyethylene ether, wherein the mass percentage of disodium sulfosuccinate in the emulsifier can be 30%, 35%, 40%, 45%, or 50%; the emulsifier is a mixture of disodium sulfosuccinate and hydroxyethyl cellulose, wherein the mass percentage of disodium sulfosuccinate in the emulsifier can be 30%, 35%, 40%, 45%, or 50%.

[0022] The inventors discovered that when the emulsifier is further selected as a mixture of disodium sulfosuccinate monoester and other emulsifiers, and the mass percentage of disodium sulfosuccinate monoester in the emulsifier is limited to 30-50%, not only is the initial paint film removal rate high, but the paint remover can also be reused, with a paint removal rate of over 80% obtained in the second cycle.

[0023] In a second aspect, the present invention provides the application of the paint remover in removing any one or more of polyurethane paint, styrene-acrylic paint, and epoxy paint.

[0024] For example, the paint remover can be applied to remove paint from a car bumper.

[0025] In a third aspect, the present invention provides a paint removal method, the paint removal method comprising the following steps: immersing the part to be painted in the paint remover described in the present invention, polishing after immersion, and then cleaning.

[0026] In the paint removal method provided by the present invention, the parts to be painted are first soaked in paint remover. During the soaking process, the paint remover reacts with the paint film, causing the paint film to swell, thereby reducing the adhesion between the paint and the substrate. Then, the paint film is polished. This not only makes it easier to remove the paint film by polishing, but also does not require strong friction during the polishing process, which can reduce power and energy consumption, and also causes less damage to the substrate surface.

[0027] In a preferred embodiment of the preparation method described in this invention, the soaking time is 10-40 min and the polishing time is 20-40 min.

[0028] The inventors discovered that when the soaking time and polishing time are within the above range, production time can be saved and efficiency improved while ensuring a good paint film removal rate.

[0029] Preferably, the polishing is performed using a friction machine.

[0030] Preferably, the power of the friction machine is >7.5KW / h.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] This invention provides a paint remover that achieves a high paint removal rate (over 85%) through the combined action of specific ester compounds and emulsifiers. The remover is reusable, maintaining a good paint removal rate even after a second recycling. Furthermore, the paint remover formulation does not damage the removed material, allowing for high-quality recycling. The paint remover contains over 85% water by mass, indicating a low solvent content, making the overall formulation environmentally friendly and non-toxic, meeting green environmental protection requirements. Detailed Implementation

[0033] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0034] Unless otherwise specified, the reagents, methods, and equipment used in this invention are all conventional reagents, methods, and equipment in the art. The reagents used in the parallel experiments of the examples and comparative examples are consistent.

[0035] Paint strips to be stripped: The strips to be stripped are 5cm in length, 5cm in width, and 3cm in height. The paint consists of three layers: primer, color coat, and top coat. The primer, color coat, and top coat are epoxy resin paint, styrene-acrylic resin paint, and polyurethane paint, respectively. The epoxy resin thickness is 15μm, the styrene-acrylic resin thickness is 40μm, and the polyurethane thickness is 50μm. The substrate is PP resin; the paint on the substrate surface is applied by spraying.

[0036] Examples 1-20 and Comparative Examples 1-5

[0037] Examples 1-20 and Comparative Examples 1-5 of the present invention provide a paint remover, the component content (percentage) of which is shown in Tables 1-3;

[0038] Table 1

[0039]

[0040]

[0041] Table 2

[0042]

[0043] Table 3

[0044]

[0045] The preparation methods of the paint removers provided in Examples 1-20 and Comparative Examples 1-5 are as follows:

[0046] Mix the above components evenly according to the mass percentages of the components in Table 1-3 to obtain the paint remover.

[0047] Experimental Example 1

[0048] The present invention provides a paint removal method, wherein the paint removal method specifically involves immersing the sample to be removed in the paint remover provided in Examples 1-20 and Comparative Examples 1-5 for 20 minutes, and after immersion, removing it and polishing it with a friction machine for 20 minutes with a power of 9KW / h, followed by washing.

[0049] Then, the process was repeated for a second time. The samples to be de-painted were immersed in the paint removers of Examples 1-20 and Comparative Examples 1-5, which had already been de-painted once, for 20 minutes. After immersion, they were taken out and polished with a friction machine for 20 minutes. The power of the friction machine was 9 KW / h. Then, they were washed.

[0050] Experimental Example 2

[0051] The present invention provides a paint removal method, wherein the paint removal method specifically involves immersing the sample strip to be removed in a commercially available paint remover for 20 minutes, removing it after immersion and polishing it with a friction machine for 20 minutes with a power of 9 kW / h, followed by washing.

[0052] Among them, three commercially available paint removers were tested. The first one is benzyl alcohol-based, with the following specific components: 30-40 parts sodium hydroxide, 40-60 parts benzyl alcohol, and 5-8 parts water-soluble cellulose.

[0053] The second type is xylene, with the following specific components: xylene 25-35%, ethyl acetate 10-14%, N-methylpyrrolidone 6-10%, and ethylene glycol anisole 2-4%.

[0054] The third type is dichloromethane-based, with the following specific components: 30-50 parts methylpyrrolidone, 30-50 parts dichloromethane, 10-20 parts hydroxyethyl cellulose, 1-5 parts sodium dodecyl sulfonate surfactant, 3-15 parts fatty alcohol polyoxyethylene ether, and 6-8 parts thickener.

[0055] Experimental Example 3

[0056] The present invention provides a paint removal method, wherein the paint removal method specifically involves using a shot peening machine to recover the sample to be paint removed, as is done in the prior art.

[0057] Example of effect 1

[0058] The effect of the present invention is verified in Examples 1-3. The paint film removal rate and the effect on the sample base layer under the paint film after paint removal are recorded. Specifically, the paint film removal rate and the impact strength of the notch of the sample after paint film removal are recorded.

[0059] The calculation methods for the first and second paint film removal rates are as follows: Removal rate = Sum of the areas of the cleaned paint film parts in the washed sample / Surface area of ​​the original sample * 100%;

[0060] The notched impact strength of the sample was tested in accordance with GB / T 1043.2-2018; the initial notched impact strength of the sample to be peeled was 26, and the notched impact strength retention rate after the first peeling was obtained from the test. The calculation method was: retention rate = impact strength after peeling / notched impact strength of the initial sample to be peeled * 100%.

[0061] The test results are shown in Table 4; where, if the first removal rate is less than 80%, the second removal rate is not calculated, and is indicated by " / ".

[0062] Table 4

[0063]

[0064]

[0065] As can be seen from Table 4, when the technical solution of the present invention is adopted, the paint remover has a first removal rate of more than 85% for the paint film and a notch impact strength retention rate of more than 86% for the sample. That is, the paint remover prepared by the technical solution provided by the present invention and the paint removal method of the present invention not only have excellent paint film removal effect, but also do not damage the sample base layer.

[0066] As can be seen from Examples 1-8 and Comparative Examples 1-2, only when using the ester compounds provided by this invention can a good removal efficiency be obtained, meeting the requirement of a first removal rate of over 85%. If the ester compounds are not provided by this invention, the first removal rate is significantly reduced, and the impact strength retention rate also shows a decreasing trend. As can be seen from Examples 1-6, when using a mixture of two ester compounds, the first removal rate is more excellent, and it also has a better second removal rate. In particular, when butyl acetate and isopropyl acetate are used together, the first removal rate is over 98%, and the second removal rate is over 98%. As can be seen from Examples 5 and 7-8, the mass ratio of butyl acetate to isopropyl acetate in the ester compounds also affects the performance of the paint remover. When the mass percentage of butyl acetate is further optimized to be 70-90%, the second paint removal rate of the obtained paint remover is better, and the damage to the substrate is lower.

[0067] As can be seen from Examples 5, 9-14, and Comparative Example 3, only when using the emulsifier provided by this invention can a good removal efficiency be achieved, meeting the requirement of a first removal rate of over 85%. If the emulsifier is not provided by this invention, the first removal rate is significantly reduced. As can be seen from Examples 5 and 9-17, when using a mixture of the two emulsifiers, the first removal rate is more excellent, and the second removal rate is also better. In particular, when MES and HEC are used together, the first removal rate is over 94%, and the second removal rate is over 85%. As can be seen from Examples 5 and 15-17, the mass ratio of MES to HEC in the emulsifier also affects the performance of the paint remover. When the mass percentage of MES is further optimized to 30-50%, the second paint removal rate of the obtained paint remover is better, and the damage to the substrate is lower.

[0068] As can be seen from Examples 5 and 18-20, the amount of ester compounds and emulsifiers also affects the performance of paint remover;

[0069] As can be seen from Example 5 and Comparative Examples 4-5, when only ester compounds or emulsifiers are added, the paint removal effect of the obtained products is significantly reduced;

[0070] As can be seen from Example 5 of Experiment 1 and Experiments 2-3, the method provided by the present invention, compared with the prior art, can maintain a good paint removal rate without damaging the substrate, and can achieve efficient recycling. In addition, this paint remover can be repeatedly recycled.

[0071] Example 2

[0072] The number of cycles in Examples 1, 5-7, 13-15, and 17-18 of the efficacy verification test example 1 of the present invention was recorded. The removal rate and notch impact strength retention rate under different number of cycles were recorded. The calculation method was consistent with that in the efficacy example 1. The data obtained are shown in Table 5.

[0073] Table 5

[0074]

[0075] As can be seen from Table 5, the paint remover obtained by using the technical solution of the present invention can still maintain an 85% removal rate after 5 cycles of use, and the impact strength retention rate can still be above 90%. That is, the paint remover provided by the present invention can meet the goal of recycling, thereby achieving the effect of energy saving and environmental protection.

[0076] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A paint remover, characterized by, The paint remover is composed of the following components by mass fraction: The ester compound is 3-10 parts, the emulsifier is 0.3-1.5 parts, and the water is 88-97 parts; The structural formula of the ester compound is R1COOR2, wherein R1 is an alkyl or alkenyl group with 1-5 carbon atoms, and R2 is an alkyl group with 3-4 carbon atoms; The emulsifier is disodium sulfosuccinate monoester; or the emulsifier is hydroxyethyl cellulose; or the emulsifier is a mixture of disodium sulfosuccinate monoester and sodium dodecyl benzene sulfonate; or the emulsifier is a mixture of disodium sulfosuccinate monoester and fatty alcohol polyoxyethylene ether; or the emulsifier is a mixture of disodium sulfosuccinate monoester and hydroxyethyl cellulose; or the emulsifier is fatty alcohol polyoxyethylene ether.

2. The paint remover according to claim 1, characterized in that, The paint remover includes the following components by mass fraction: ester compound 5-8 parts, emulsifier 0.5-1.2 parts.

3. The paint remover according to claim 1, characterized by, The ester compound satisfies at least one of the following (a)-(b): (a) the R1 is any one of ethyl, propenyl, methyl propenyl, ethyl propenyl; (b) the R2 is isopropyl or butyl.

4. The paint remover according to claim 3, characterized in that, The ester compound is at least one of isopropyl acetate, butyl acetate, butyl acrylate, and butyl methacrylate.

5. The paint remover according to claim 4, characterized in that, In the ester compound, the mass percentage of butyl acetate is 70-90%.

6. The paint remover according to claim 1, characterized by When the emulsifier is a mixture, the mass percentage of disodium sulfosuccinate monoester in the emulsifier is 30-50%.

7. Use of the paint remover according to any one of claims 1-6 for removing any one or several of polyurethane paint, styrene-acrylic resin paint, and epoxy resin paint.

8. A paint removal method characterized by, The paint removal method includes the following steps: Soaking the paint removal part in the paint remover according to any one of claims 1-6, polishing after the soaking is completed, and then cleaning.

9. The paint removal method according to claim 8, characterized by, The soaking time is 10-40 min, and the polishing time is 20-40 min.

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