A paint remover for steel-aluminum composite material
By preparing a paint remover containing alkaline substances, lipase components, and corrosion inhibitors, the problems of poor paint removal effect and corrosion risk of steel-aluminum composite materials were solved, achieving a fast and environmentally friendly paint removal effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DONGGUAN SIHUI SURFACE PROCESSING TECH CO LTD
- Filing Date
- 2024-06-13
- Publication Date
- 2026-06-02
Smart Images
Figure BDA0004891378280000021 
Figure BDA0004891378280000051 
Figure BDA0004891378280000061
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal material surface treatment technology, specifically relating to a paint remover for steel-aluminum composite materials. Background Technology
[0002] Paints, with their decorative, anti-corrosion, aesthetic, and various other functions, are increasingly widely used in industrial production and daily life. Defects in paint products, such as bumps, pinholes, thick edges, and whitening, require paint removal and recoating. Traditional paint removal methods include chemical paint removal, laser paint removal, and mechanical removal. Mechanical removal is rarely used now because it is difficult to completely remove paint; laser paint removal is limited to low- and mid-range products due to its high cost; chemical paint removal has advantages such as relatively low cost, good paint removal effect, and less corrosion to the substrate, and will remain the mainstream paint removal technology for a considerable period of time.
[0003] Paint removers generally consist of solvents, accelerators, and anti-volatility agents, supplemented with other necessary special additives. They rapidly remove the paint film through a series of physical and chemical processes, including dissolution, penetration, swelling, peeling, and reaction. Early paint removers mostly contained dichloromethane, phenol, and low-boiling-point, volatile organic solvents, which were highly toxic and volatile, posing significant hazards to the health of operators and the environment. Therefore, the development of low-toxicity, low-volatility, and non-corrosive water-based paint removers has become a research hotspot.
[0004] However, water-based paint removers on the market are generally alkaline paint removers, mainly composed of strong alkali, supplemented with co-solvents, surfactants and corrosion inhibitors. They destroy the integrity of the paint film through saponification and dissolve the paint film through emulsification. The advantages are low volatility and small fluctuations in paint removal ability after multiple uses. The disadvantage is that they are prone to corroding the substrate. Summary of the Invention
[0005] The purpose of this invention is to provide a paint remover for steel-aluminum composite materials. The method involves using alkaline substances, lipase components, solvents, surfactants, co-solvents, corrosion inhibitors, and water as raw materials. This product is used for paint removal from steel-aluminum composite materials. During use, heating is required. On one hand, the alkaline substances saponify some groups in the paint, dissolving them in the solvent and water. On the other hand, heating and steaming the paint film reduces its strength and adhesion to the metal. Then, the wetting, penetration, and affinity of the surfactants, along with the corrosion inhibitors protecting the aluminum from corrosion by the alkaline substances, achieve the goal of preventing corrosion of the substrate and quickly completing paint removal.
[0006] The objective of this invention can be achieved through the following technical solutions:
[0007] A paint remover for steel-aluminum composite materials comprises the following components in weight percentages:
[0008]
[0009] Furthermore, the alkaline substances are potassium hydroxide and / or sodium hydroxide, which are used to saponify some groups in the paint, making them soluble in water.
[0010] Furthermore, the lipase component is prepared through the following steps:
[0011] Block polyether F127, sodium perchlorate monohydrate and glacial acetic acid were added sequentially to deionized water and stirred for 5-10 min. Cerium ammonium nitrate and terephthalic acid were added and the mixture was magnetically stirred at 60°C for 20 min. After centrifugation, the precipitate was washed, soaked and dried to obtain the carrier.
[0012] The carrier was added to the lipase solution, stirred at room temperature for 1 hour, centrifuged at 4°C for 3 minutes, and the precipitate was washed three times with HEPES buffer at pH 7.0 to obtain the lipase component.
[0013] Furthermore, the ratio of deionized water, block polyether F127, sodium perchlorate monohydrate, glacial acetic acid, cerium ammonium nitrate, and terephthalic acid is 6 mL: 100 mg: 150 mg: 0.3 mL: 548 mg: 166 mg.
[0014] Furthermore, the ratio of carrier to lipase solution is 10 mg: 2-4 mL, the concentration of lipase in the lipase solution is 3 mg / mL, and the lipase solution is prepared by lipase and HEPES buffer with a concentration of 50 mmol / L.
[0015] Furthermore, the lipase was Candida antarcticis lipase B (CALB).
[0016] Using a cerium-based metal-organic framework with high porosity, large surface area, and well-developed interconnected pore structure as a carrier, and Candida antarcticis lipase B as the active substance, the lipase component was prepared by physical adsorption. It exhibits good catalytic performance, promotes the breaking of ester bonds in the paint film, and improves the paint removal effect of the paint remover. In addition, the introduction of the cerium-based metal-organic framework carrier improves the stability of Candida antarcticis lipase B in high temperature, acid and alkali and organic solvents.
[0017] Furthermore, the solvent is propylene carbonate, which is an excellent low-toxicity solvent that is miscible with oily substances, olefins, and aromatics.
[0018] Furthermore, the surfactant ester is a fatty alcohol polyoxyethylene ether, specifically one or more of fatty alcohol polyoxyethylene ether AEO3, fatty alcohol polyoxyethylene ether AEO5, fatty alcohol polyoxyethylene ether AEO-9, and fatty alcohol polyoxyethylene ether AEO-10. They have fixed hydrophilic and lipophilic groups, which can be oriented in the paint remover, thereby reducing the surface tension and preventing the dissolved paint from re-adhering to the material surface.
[0019] Furthermore, the co-solvent is sodium benzoate, which can form complexes with some substances in the paint film to increase the solubility of poorly soluble substances in the solvent.
[0020] Furthermore, the corrosion inhibitor is a compound of inorganic and organic corrosion inhibitors in a mass ratio of 4-6:1-2, which can prevent aluminum-steel substrates from being corroded in alkaline environments.
[0021] Furthermore, the inorganic corrosion inhibitor is a silicate, specifically sodium metasilicate.
[0022] Furthermore, the organic corrosion inhibitor is prepared through the following steps:
[0023] Add glycine and potassium hydroxide to methanol, stir at room temperature for 10-15 min, add 3,4,5-trihydroxybenzaldehyde, and stir the reaction at 45-50℃ for 4-6 h under nitrogen protection. After the reaction is completed, cool to room temperature, filter, wash the filter cake with deionized water and dry it.
[0024] In the above reaction, the molar ratio of L-histidine, potassium hydroxide and 3,4,5-trihydroxybenzaldehyde is 1:1:1. Using L-histidine and 3,4,5-trihydroxybenzaldehyde as raw materials, an organic corrosion inhibitor is obtained through the condensation reaction between aldehyde and amino groups.
[0025] The above-mentioned method for preparing paint remover for steel-aluminum composite materials includes the following steps:
[0026] Step A: Add water and alkaline substance to the reaction vessel in sequence, and stir at 400-500 rpm for 30 minutes to obtain component one;
[0027] Step B: Then add the lipase component, solvent, surfactant, cosolvent, and corrosion inhibitor to component one in sequence, and stir at 400-500 rpm for 30 minutes to obtain component two;
[0028] Step C: Sample and analyze component two, then package the materials.
[0029] The beneficial effects of this invention are:
[0030] (1) The paint remover provided by the present invention is made from alkaline substances, lipase components, solvents, surfactants, cosolvents, corrosion inhibitors and water. It is used for paint removal of steel-aluminum composite materials. It needs to be heated when used. On the one hand, the alkaline substances saponify some groups in the paint and dissolve them in the solvent and water. On the other hand, heating and steaming the paint film reduces its strength and adhesion to the metal. Then, by utilizing the wetting, penetration and affinity of the surfactant, the catalytic effect of the lipase components and the protective effect of the corrosion inhibitor on the steel-aluminum substrate, the purpose of paint removal is achieved without corroding the substrate and quickly completing the paint removal.
[0031] (2) This invention incorporates propylene carbonate, lipase components, and organic corrosion inhibitors into the paint remover, which synergistically enhance the paint remover's excellent paint removal effect. This is because propylene carbonate is a low-toxicity organic solvent with high affinity for paint films, capable of dissolving and swelling the paint film, thereby reducing the adhesion between the paint film and steel / aluminum, as well as the bonding degree within the paint film; the lipase component is more stable than simple lipase under alkaline and high-temperature conditions, and the ester bonds in the paint film can be hydrolyzed by the lipase component, thereby promoting the dissolution of the paint film and the penetration of propylene carbonate, improving the paint removal efficiency; the organic corrosion inhibitor contains hydrophilic carboxyl groups and phenolic structures, which on the one hand provide hydrogen bonds, enabling the formation of hydrogen bonds with carbonyl and ether oxygen atoms in the paint film, promoting paint film dissolution, and on the other hand, cause the chemical bonds to break through the ester groups by nucleophilic attack of the phenolic hydroxyl groups, resulting in irreversible changes to the paint film, further enhancing the paint removal effect.
[0032] (3) In this invention, organic and inorganic corrosion inhibitors are added to the paint remover. The synergistic effect makes the paint remover have a very low corrosion rate on steel and aluminum substrates. Among them, the inorganic corrosion inhibitor is sodium silicate, which is widely used in aluminum alloy corrosion protection. However, when sodium silicate is used alone as a corrosion inhibitor, it has problems such as slow film formation and voids in the film. In this regard, this invention introduces an organic corrosion inhibitor into the paint remover. The organic corrosion inhibitor contains -C=N- functional groups and has active adsorption centers, which can be adsorbed on the surface of steel and aluminum substrates. When used together with sodium silicate, the protective film formed is more dense, thereby greatly reducing the corrosion rate and improving the corrosion inhibition rate. Detailed Implementation
[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0034] The Antarctic Candida lipase B (CALB) used in this invention was purchased from Beijing Gaoruisen Biotechnology Co., Ltd., and the block polyether F127 was purchased from Shanghai Sigma-Aldrich Trading Co., Ltd., which will not be described in detail below.
[0035] Example 1
[0036] A paint remover for steel-aluminum composite materials comprises the following components in weight percentages:
[0037]
[0038]
[0039] The lipase component is prepared by the following steps:
[0040] 100 mg of block polyether F127, 150 mg of sodium perchlorate monohydrate and 0.3 mL of glacial acetic acid were added sequentially to 6 mL of deionized water and stirred for 5 min. Then, 548 mg of cerium ammonium nitrate and 166 mg of terephthalic acid were added and the mixture was magnetically stirred at 60 °C for 20 min. After centrifugation, the precipitate was washed once with deionized water and twice with N,N-dimethylformamide. Then, it was soaked alternately in deionized water and anhydrous ethanol for 3 days, with the soaking solution being changed every half day. Finally, it was dried at 60 °C to constant weight to obtain the carrier.
[0041] 10 mg of the carrier was added to 2 mL of lipase solution. The concentration of Candida antarcticis lipase B (CALB) in the lipase solution was 3 mg / mL. The lipase solution was prepared by Candida antarcticis lipase B (CALB) and HEPES buffer with a concentration of 50 mmol / L. The mixture was stirred at room temperature for 1 h, centrifuged at 4 °C for 3 min, and the precipitate was washed 3 times with HEPES buffer with pH = 7.0 to obtain the lipase fraction.
[0042] The surfactant ester is fatty alcohol polyoxyethylene ether AEO3.
[0043] The corrosion inhibitor is a compound of sodium metasilicate nonahydrate and organic corrosion inhibitor in a mass ratio of 4:1.
[0044] Organic corrosion inhibitors are prepared through the following steps:
[0045] Add 0.1 mol glycine and 0.1 mol potassium hydroxide to 100 mL methanol, stir at room temperature for 10 min, add 0.1 mol 3,4,5-trihydroxybenzaldehyde, and stir the mixture at 45 °C for 4 h under nitrogen protection. After the reaction is complete, cool to room temperature, filter, wash the filter cake with deionized water and dry it.
[0046] The above-mentioned method for preparing paint remover for steel-aluminum composite materials includes the following steps:
[0047] Step A: Add water and alkaline substance to the reaction vessel in sequence, stir at 400 rpm for 30 minutes to obtain component one;
[0048] Step B: Then add the lipase component, solvent, surfactant, cosolvent, and corrosion inhibitor to component one in sequence, and stir at 400 rpm for 30 minutes to obtain component two;
[0049] Step C: Sample and analyze component two, then package the materials.
[0050] Example 2
[0051] A paint remover for steel-aluminum composite materials comprises the following components in weight percentages:
[0052]
[0053] The lipase component is prepared by the following steps:
[0054] 100 mg of block polyether F127, 150 mg of sodium perchlorate monohydrate and 0.3 mL of glacial acetic acid were added sequentially to 6 mL of deionized water and stirred for 8 min. Then, 548 mg of cerium ammonium nitrate and 166 mg of terephthalic acid were added and the mixture was magnetically stirred at 60 °C for 20 min. After centrifugation, the precipitate was washed once with deionized water and twice with N,N-dimethylformamide. Then, it was soaked alternately in deionized water and anhydrous ethanol for 3 days, with the soaking solution being changed every half day. Finally, it was dried at 60 °C to constant weight to obtain the carrier.
[0055] 10 mg of the carrier was added to 3 mL of lipase solution. The concentration of Candida antarcticis lipase B (CALB) in the lipase solution was 3 mg / mL. The lipase solution was prepared by Candida antarcticis lipase B (CALB) and HEPES buffer with a concentration of 50 mmol / L. The mixture was stirred at room temperature for 1 h, centrifuged at 4 °C for 3 min, and the precipitate was washed 3 times with HEPES buffer with pH = 7.0 to obtain the lipase fraction.
[0056] The surfactant ester is fatty alcohol polyoxyethylene ether AEO5.
[0057] The corrosion inhibitor is a compound of sodium metasilicate nonahydrate and organic corrosion inhibitor in a mass ratio of 5:1.5.
[0058] Organic corrosion inhibitors are prepared through the following steps:
[0059] Add 0.1 mol glycine and 0.1 mol potassium hydroxide to 100 mL methanol, stir at room temperature for 12 min, add 0.1 mol 3,4,5-trihydroxybenzaldehyde, and stir the mixture at 48 °C for 5 h under nitrogen protection. After the reaction is complete, cool to room temperature, filter, wash the filter cake with deionized water and dry it.
[0060] The above-mentioned method for preparing paint remover for steel-aluminum composite materials includes the following steps:
[0061] Step A: Add water and alkaline substance to the reaction vessel in sequence, stir at 450 rpm for 30 minutes to obtain component one;
[0062] Step B: Then add the lipase component, solvent, surfactant, cosolvent, and corrosion inhibitor to component one in sequence, and stir at 450 rpm for 30 minutes to obtain component two;
[0063] Step C: Sample and analyze component two, then package the materials.
[0064] Example 3
[0065] A paint remover for steel-aluminum composite materials comprises the following components in weight percentages:
[0066]
[0067] The alkaline substance is composed of potassium hydroxide and sodium hydroxide in a mass ratio of 1:1.
[0068] The lipase component is prepared by the following steps:
[0069] 100 mg of block polyether F127, 150 mg of sodium perchlorate monohydrate and 0.3 mL of glacial acetic acid were added sequentially to 6 mL of deionized water and stirred for 10 min. Then, 548 mg of cerium ammonium nitrate and 166 mg of terephthalic acid were added and the mixture was magnetically stirred at 60 °C for 20 min. After centrifugation, the precipitate was washed once with deionized water and twice with N,N-dimethylformamide. Then, it was soaked alternately in deionized water and anhydrous ethanol for 3 days, with the soaking solution being changed every half day. Finally, it was dried at 60 °C to constant weight to obtain the carrier.
[0070] 10 mg of the carrier was added to 4 mL of lipase solution. The concentration of Candida antarcticis lipase B (CALB) in the lipase solution was 3 mg / mL. The lipase solution was prepared by Candida antarcticis lipase B (CALB) and HEPES buffer with a concentration of 50 mmol / L. The mixture was stirred at room temperature for 1 h, centrifuged at 4 °C for 3 min, and the precipitate was washed 3 times with HEPES buffer with pH = 7.0 to obtain the lipase fraction.
[0071] The surfactant ester is fatty alcohol polyoxyethylene ether AEO-9.
[0072] The corrosion inhibitor is a compound of sodium metasilicate nonahydrate and organic corrosion inhibitor in a mass ratio of 6:2.
[0073] Organic corrosion inhibitors are prepared through the following steps:
[0074] Add 0.1 mol glycine and 0.1 mol potassium hydroxide to 100 mL methanol, stir at room temperature for 15 min, add 0.1 mol 3,4,5-trihydroxybenzaldehyde, and stir the mixture at 50 °C for 6 h under nitrogen protection. After the reaction is complete, cool to room temperature, filter, wash the filter cake with deionized water and dry it.
[0075] The above-mentioned method for preparing paint remover for steel-aluminum composite materials includes the following steps:
[0076] Step A: Add water and alkaline substance to the reaction vessel in sequence, stir at 500 rpm for 30 minutes to obtain component one;
[0077] Step B: Then add the lipase component, solvent, surfactant, cosolvent, and corrosion inhibitor to component one in sequence, and stir at 500 rpm for 30 minutes to obtain component two;
[0078] Step C: Sample and analyze component two, then package the materials.
[0079] Comparative Examples 1-3
[0080] Compared with Example 1, the difference is that the weight percentages of lipase component, propylene carbonate and organic corrosion inhibitor in Comparative Example 1 are as shown in Table 1, while the other operating steps and parameters remain unchanged.
[0081] Table 1
[0082] Lipase components (%) Propylene carbonate (%) Organic corrosion inhibitors (%) Comparative Example 1 0 12.5 3.5 Comparative Example 2 10 0 6 Comparative Example 3 5.5 10.5 0
[0083] Comparative Example 4
[0084] Compared with Example 1, the difference is that the corrosion inhibitor in Comparative Example 4 is sodium metasilicate nonahydrate, while the other raw materials, operating steps and parameters remain unchanged.
[0085] Comparative Example 5
[0086] Compared with Example 1, the difference is that all the corrosion inhibitors in Comparative Example 5 are organic corrosion inhibitors, and the preparation process of the organic corrosion inhibitors and the other raw materials, operation steps and parameters of the paint remover remain unchanged.
[0087] The paint removers prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to performance tests, and the test procedures are as follows:
[0088] (1) Paint removal efficiency
[0089] The test substrate was an aluminum alloy sheet. First, a 100μm thick liquid epoxy primer was sprayed on and baked at 160℃ for curing. Then, a 70μm thick acrylic resin powder coating was sprayed on as a transparent topcoat and cured at 180℃.
[0090] The paint removal efficiency of the paint remover was determined according to the method specified in HG / T 3381-2003. The paint removal temperature was 55℃. The paint removal efficiency was calculated using the following formula: Paint removal efficiency = Area of wrinkled and soft paint film / Total area of paint film before paint removal × 100%.
[0091] (2) Corrosive
[0092] Unpainted aluminum alloy sheets were immersed in paint remover at 55°C for 72 hours. The weight loss Δm was measured, and the corrosiveness of the paint remover was calculated. The corrosion rate V = Δm / (s·t), where s is the area of the aluminum alloy sheet and t is the immersion time.
[0093] The results are shown in Table 1:
[0094] Table 1
[0095]
[0096] As can be seen from the data recorded in Table 1, the paint remover prepared by this invention has excellent paint film removal performance. Specifically, as can be seen from Examples 1-3 and Comparative Examples 1-3, propylene carbonate, lipase component, and organic corrosion inhibitor synergistically result in the prepared paint remover having excellent paint removal effect. Furthermore, as can be seen from Examples 1-3 and Comparative Examples 4-5, the organic corrosion inhibitor and inorganic corrosion inhibitor synergistically result in the prepared paint remover having a very low corrosion rate on steel and aluminum substrates.
[0097] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0098] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A paint remover for steel-aluminum composite materials, characterized in that, The components include the following components in weight percentage: Alkaline substances 5%-8%; Lipase component 5%-10%; Solvent 10%-16%; Surfactant 5%-10%; Cosolvent 6%-13%; Corrosion inhibitor 5%-8%; Water balance; The lipase component is prepared by the following steps: Block polyether F127, sodium perchlorate monohydrate and glacial acetic acid were added sequentially to deionized water and stirred for 5-10 min. Cerium ammonium nitrate and terephthalic acid were added and the mixture was magnetically stirred at 60°C for 20 min. After centrifugation, the precipitate was washed, soaked and dried to obtain the carrier. The carrier was added to the lipase solution, stirred at room temperature for 1 hour, centrifuged at 4°C for 3 minutes, and the precipitate was washed three times with HEPES buffer at pH 7.0 to obtain the lipase component. The lipase is Candida antarcticis lipase B; The solvent is propylene carbonate; The corrosion inhibitor is a compound of inorganic and organic corrosion inhibitors in a mass ratio of 4-6:1-2; the inorganic corrosion inhibitor is a silicate. Organic corrosion inhibitors are prepared through the following steps: Add glycine and potassium hydroxide to methanol and stir at room temperature for 10-15 minutes. Add 3,4,5-trihydroxybenzaldehyde and stir the mixture at 45-50℃ for 4-6 hours under nitrogen protection. After the reaction is complete, cool to room temperature, filter, wash the filter cake with deionized water and dry it.
2. The paint remover for steel-aluminum composite materials according to claim 1, characterized in that, The alkaline substances are potassium hydroxide and / or sodium hydroxide.
3. The paint remover for steel-aluminum composite materials according to claim 1, characterized in that, The ratio of deionized water, block polyether F127, sodium perchlorate monohydrate, glacial acetic acid, cerium ammonium nitrate, and terephthalic acid is 6 mL: 100 mg: 150 mg: 0.3 mL: 548 mg: 166 mg.
4. The paint remover for steel-aluminum composite materials according to claim 1, characterized in that, The ratio of carrier to lipase solution was 10 mg: 2-4 mL. The concentration of lipase in the lipase solution was 3 mg / mL. The lipase solution was prepared by mixing lipase with 50 mmol / L HEPES buffer.
5. The paint remover for steel-aluminum composite materials according to claim 1, characterized in that, The surfactant is one or more of AEO-3, AEO-5, AEO-9, and AEO-10, and the cosolvent is sodium benzoate.
6. The paint remover for steel-aluminum composite materials according to claim 1, characterized in that, The molar ratio of glycine, potassium hydroxide, and 3,4,5-trihydroxybenzaldehyde is 1:1:1.