Water-based paint remover and environment-friendly paint removing method for waste aluminum ring-pull cans

Abstract

The invention belongs to the technical field of paint removers, and particularly relates to a star-structure silane sealing agent, a water-based paint remover and a preparation method and application of the star-structure silane sealing agent and the water-based paint remover. According to the invention, a star-shaped structure silane sealing agent with annular polysiloxane as a core and polyol as a side arm is designed and synthesized, the star-shaped structure silane sealing agent is added into a water-based paint remover, the annular polysiloxane shields and blocks volatilization of polar components in the paint remover, and the polyol side arm is combined with the polar components through hydrogen bond acting force, so that the water-based paint remover is formed. The volatilization failure of alcohol, ester or ketone solvents in the high-temperature paint removal process is avoided, the paint can be removed at a higher temperature, and the paint removal time is shortened. The polyol on the side arm of the sealing agent also has the effect of chelating inorganic ions, so that corrosion caused by deposition of metal ions in the aluminum alloy and influence of precipitation of calcium and magnesium ions in water on the emulsification effect of the oil phase component are avoided. In addition, the water-based paint remover does not contain organic solvents such as chlorinated hydrocarbon, phenols, acetone and the like, and has no influence on the health of operators and the environment.

Description

Technical Field

[0001] This application relates to the field of paint remover technology, and in particular to a star-shaped silane sealant, an aqueous paint remover, its preparation method, and its application in paint removal from waste aluminum cans. Background Technology

[0002] Paint serves to protect and decorate items, but during use, the coating film can be damaged, gradually age, or require removal of the old paint film due to the recycling of the items themselves. Old paint films are typically made of thermoplastic resins and room-temperature cross-linking resins, such as polyester paint, nitrocellulose lacquer, epoxy resin paint, acrylic ester paint, and polyurethane paint. These polymer paint films can dissolve or swell in suitable organic solvents and contain specific active functional groups, such as ester bonds, ether bonds, and amide bonds. Under the action of hot acids or alkalis, they are prone to acidolysis, alkaline hydrolysis, and other chemical reactions, leading to the breakage of their molecular chains. Therefore, old paint films are easily removed by organic solvent paint removers or alkaline and acidic paint removers. The working principle of paint removers is to break the chemical bonds of the paint film itself or reduce the adhesion between the paint film and the substrate. The solvent molecules in the paint remover penetrate into the molecular chain segments of the polymer in the paint film, causing the paint film to dissolve, or the polymer macromolecules to increase in volume, generating internal stress. When the internal stress is sufficient to break the adhesion between the paint film and the substrate, the paint film is removed.

[0003] Recycled aluminum is an indispensable resource for the sustainable development of the global aluminum industry, with vast market potential and promising prospects. Compared to electrolytic aluminum, recycled aluminum saves up to 95% of energy per ton, significantly reducing carbon dioxide and harmful emissions, thus benefiting environmental protection. As a crucial component of recycled aluminum, aluminum cans have a complex composition and are difficult to recycle, especially due to the paint film on their surface. If this paint film is not removed, it can easily cause pollution during subsequent recycling. Treating waste aluminum cans with paint removers to quickly remove the paint can reduce impurities and pollution during the recycling process.

[0004] Furthermore, to enhance their paint-removing effect, currently commercially available paint removers typically contain mixtures of strong solvents such as dichloromethane. Dichloromethane metabolizes in the human body to produce carbon monoxide, which can cause acute asphyxiation and anesthesia, as well as carcinogenicity and neurological damage. Due to the significant health and environmental risks posed by dichloromethane, the US EPA has banned or strictly restricted the sale and use of paint removers with high dichloromethane content in the consumer market. In addition, paint removers also contain volatile organic compounds (VOCs), which can easily pose environmental and human health risks. Therefore, developing safer and more environmentally friendly water-based paint removers as alternatives to solvent-based paint removers containing dichloromethane can meet the demands for safety and environmental protection. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the technical problem to be solved by this invention is to design and synthesize a star-shaped silane sealant. The silane sealant has a cyclic polysiloxane core and side arms containing polyols. It is combined with low-toxicity, high-boiling-point alcohols, ketones, or esters as the effective components of a paint remover. The mixture is then emulsified to obtain a water-based paint remover, which improves the paint removal speed while reducing the health risks of the paint remover and its corrosion of aluminum alloys.

[0006] In a first aspect, a star-shaped silane blocking agent includes a polysiloxane core and side arms containing a polyol, wherein the star-shaped silane blocking agent comprises a structure with the general formula [insert general formula here]. , Compounds or mixtures of both;

[0007] Wherein, R1 is selected from methyl or phenyl, and R2 is a side arm containing a polyol, the side arm containing... or Structure; R3 is selected from hydrocarbon groups with 1 to 12 carbon atoms; R4 and R5 may be the same or different, and are independently selected from methyl or phenyl; m and n are positive integers greater than or equal to 1;

[0008] Preferably, n=3-6; preferably, m=1

[0009] Preferably, R3 is selected from hydrocarbon groups having 1 to 6 carbon atoms;

[0010] Preferably, the polysiloxane core is selected from... or ;

[0011] Preferably, the side arm containing the polyol is selected from: or .

[0012] Secondly, the preparation method of the star-shaped silane blocking agent described above includes: performing a hydrosilylation reaction between a monomer containing vinyl and epoxy groups and a hydrogen-containing silane cyclic compound to obtain an addition product, and then reacting the addition product with an alkanolamine compound to obtain the star-shaped silane blocking agent.

[0013] Furthermore, the terminal vinyl polysiloxane is subjected to a hydrosilylation reaction with a hydrogen-containing silane cyclic compound, and then subjected to a hydrosilylation reaction with a monomer containing vinyl and epoxy groups to obtain the addition product.

[0014] Preferably, the vinyl-terminated polysiloxane is selected from 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (vinyl double-terminated);

[0015] Preferably, the monomer containing vinyl and epoxy groups is selected from one or more combinations of allyl glycidyl ether, 4-vinylphenyl glycidyl ether, 4-vinylbenzyl glycidyl ether, 4-vinyl-1-cyclohexene-1,2-epoxy, glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexyl acrylate, and 3,4-epoxycyclohexyl methacrylate.

[0016] Preferably, the monomer containing vinyl and epoxy groups is selected from allyl glycidyl ether.

[0017] Preferably, the alkanolamine compound is selected from one or a combination of two of diethanolamine and diisopropanolamine;

[0018] Preferably, in the hydrosilylation reaction, the molar ratio of silane groups (Si-H) in the hydrogen-containing silane ring to vinyl groups (C=C) in the vinyl-terminated polysiloxane is (4-8):1;

[0019] Preferably, in the hydrosilylation reaction, the molar ratio of the silane group (Si-H) in the hydrogen-containing silane ring to the vinyl group (C=C) in the monomer containing vinyl and epoxy groups is 1:(1.0-1.3).

[0020] Furthermore, platinum complexes are used as catalysts in hydrosilylation reactions;

[0021] The platinum complex is selected from one or more combinations of platinum-isopropanol complex catalysts, platinum-ene complex catalysts, platinum-phosphine amine complex catalysts, and platinum-(N-heterocyclic carbene) complexes;

[0022] Preferably, the hydrosilylation catalyst is selected from platinum-olefin complex catalysts;

[0023] Further preferred, the hydrosilylation catalyst is selected from: platinum-divinyltetramethyldisiloxane complex (Castel catalyst).

[0024] Preferably, in the hydrosilylation reaction, the amount of platinum complex is 0.08-0.8 wt% of the total reactants.

[0025] Preferably, after the hydrosilylation reaction is completed, excess unreacted monomers containing vinyl and epoxy groups are removed by vacuum distillation.

[0026] Preferably, after the reaction between the alkanolamine compound and the addition product is complete, excess unreacted alkanolamine compound is removed by vacuum distillation.

[0027] Preferably, either nitrogen or an inert gas is continuously introduced during the hydrosilylation reaction.

[0028] Thirdly, the use of the star-shaped silane sealant described above in paint removers.

[0029] Fourthly, a water-based paint remover, comprising:

[0030] Alcohol solvents, ketone or ester solvents, basic activators, thickeners, the star-shaped silane blocking agents mentioned above, corrosion inhibitors, anionic surfactants, nonionic surfactants, and water;

[0031] The alcohol solvent is selected from alcohols with a boiling point ≥100℃ at normal pressure; preferably, the alcohol solvent is selected from one or more combinations of n-butanol, isobutanol, butanediol, cyclopentanol, cyclohexanol, benzyl alcohol and phenethyl alcohol.

[0032] Further optimization is to select benzyl alcohol as the alcohol solvent.

[0033] The ketone or ester solvents are selected from ketones or esters with a boiling point ≥100℃ at normal pressure; preferably, the ketone solvents are selected from one or more combinations of: pentanone, hexanone, cyclopentanone, cyclohexanone, methyl isobutyl ketone, diisobutyl ketone, methyl pentanone, isopropylidene acetone, acetophenone, isophorone, and N-methylpyrrolidone; preferably, the ester solvents are selected from one or more combinations of: butyl acetate, propylene glycol methyl ether acetate, ethyl lactate, butyl lactate, methyl acetoacetate, ethyl acetoacetate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, methyl benzoate, ethyl benzoate, diethyl phthalate, methyl oleate, dimethyl carbonate, and propylene carbonate.

[0034] Further optimization involves selecting isophorone as the ketone solvent;

[0035] Further preferred, the ester solvent is selected from ethyl lactate.

[0036] The alkaline activator is selected from one or more combinations of monoethanolamine, isopropanolamine, diethanolamine, diisopropanolamine, triethanolamine, triisopropanolamine and hexamethylenetetramine;

[0037] The thickener is selected from one or more combinations of sodium polyacrylate, polyvinyl alcohol, polyacrylamide, and sodium carboxymethyl cellulose;

[0038] The corrosion inhibitor is selected from one or a combination of two of benzotriazole and methylbenzotriazole;

[0039] Anionic surfactants are selected from one or a combination of two of sulfate surfactants and sulfonate surfactants;

[0040] Preferably, the sulfate surfactant is selected from one or a combination of two of sodium dodecyl sulfate and sodium fatty alcohol polyoxyethylene ether sulfate;

[0041] Preferably, the sulfonate surfactant is selected from one or a combination of two of sodium dodecylbenzenesulfonate and sodium dioctyl sulfosuccinate;

[0042] The nonionic surfactant is selected from one or more combinations of fatty alcohol polyoxyethylene ether (AEO), isomeric alcohol ether, alkyl glycoside and cashew phenol polyoxyethylene ether;

[0043] Preferably, the nonionic surfactant is selected from fatty alcohol polyoxyethylene ether (AEO).

[0044] Furthermore, the water-based paint remover comprises the following raw materials in weight percentages:

[0045] 10-30% alcohol solvent, 25-40% ketone or ester solvent, 1-10% alkaline activator, 1-5% corrosion inhibitor, 1-5% sealing agent, 1-10% anionic surfactant, 1-5% nonionic surfactant, 0.1-3% thickener, balance water.

[0046] Fifthly, the preparation method of the water-based paint remover described above includes: stirring a sealant, an alcohol solvent, a ketone or ester solvent, a corrosion inhibitor, and an alkaline activator at room temperature to obtain an oil phase component; stirring an anionic surfactant, a nonionic surfactant, a thickener, and water at room temperature to obtain an aqueous phase component; adding the oil phase component to the aqueous phase component at a speed of 100-1500 rpm, and maintaining dispersion for 10-60 minutes after addition to obtain the water-based paint remover.

[0047] Sixthly, a method for removing organic paint film from the surface of aluminum or aluminum alloy includes: immersing the aluminum or aluminum alloy with organic paint film on its surface in the water-based paint remover described above at a certain temperature, wherein the temperature is room temperature to 100°C.

[0048] Preferably, the temperature is 50-100℃;

[0049] More preferably, the temperature is 70-90℃.

[0050] Preferably, ultrasonic vibration is used to assist in paint removal during the immersion process.

[0051] The seventh aspect concerns the use of the water-based paint remover described above in the paint removal of waste aluminum cans.

[0052] The beneficial effects of this invention are as follows: A star-shaped silane sealant with a cyclic polysiloxane core and polyols as side arms is designed and synthesized. When added to a water-based paint remover, the cyclic polysiloxane provides a sealing effect similar to silicone oil, shielding and blocking the volatilization of polar components in the paint remover. The polyol side arms bind to the polar components through intermolecular forces such as hydrogen bonds, preventing alcohols, esters, or ketones from volatilizing and becoming ineffective during high-temperature paint removal. This allows for paint removal at higher temperatures and shorter removal times. The polyols in the sealant side arms also chelate inorganic ions, preventing the deposition of other metal ions in aluminum alloys that could lead to corrosion, and also preventing the precipitation of calcium and magnesium ions in hard water from affecting the emulsification effect on the oil phase components. Furthermore, the water-based paint remover does not contain highly toxic and volatile organic solvents such as chlorinated hydrocarbons, phenols, and acetone, posing no health risks to operators or the environment. Detailed Implementation

[0053] The present application will be further described in detail below with reference to the embodiments and examples. It should be understood that these embodiments and examples are for illustrative purposes only and are not intended to limit the scope of the present application. The purpose of providing these embodiments and examples is to enable a more thorough and comprehensive understanding of the disclosure of the present application. It should also be understood that the present application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various modifications or alterations without departing from the spirit of the present application, and the equivalent forms obtained also fall within the protection scope of the present application. Furthermore, numerous specific details are set forth in the following description to provide a fuller understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0054] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0055] the term

[0056] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0057] The terms "and / or," "or / and," and "and / or" as used herein include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that in this application, the technical solution undoubtedly includes technical solutions connected by "logical AND," and also undoubtedly includes technical solutions connected by "logical OR." For example, "A and / or B" includes three parallel solutions: A, B, and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, a technical solution that is connected by "logical OR"), as well as any and all combinations of A, B, C, and D, that is, combinations of any two or three of A, B, C, and D, and also combinations of all four of A, B, C, and D (that is, a technical solution that is connected by "logical AND").

[0058] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0059] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0060] In this application, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions containing the listed features.

[0061] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0062] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0063] In this application, % (w / w) and wt% both represent weight percentage, % (v / v) refers to volume percentage, and % (w / v) refers to mass-volume percentage.

[0064] All references to documents mentioned in this application are incorporated herein by reference as if each document were individually incorporated herein by reference. Unless they conflict with the inventive purpose and / or technical solution of this application, all cited documents are incorporated herein by reference in their entirety and for all purposes. When citing documents in this application, the definitions of relevant technical features, terms, nouns, phrases, etc., are also incorporated herein by reference. When citing documents in this application, examples and preferred embodiments of the cited technical features may also be incorporated herein by reference, but only to the extent that they enable the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, this application shall prevail or modifications shall be made adaptably to the description in this application.

[0065] In this application, if the specific experimental conditions are not specified in the embodiments, they are generally in accordance with conventional conditions in the art or the conditions recommended by the reagent company; the materials, reagents, etc. used in the embodiments can be purchased commercially unless otherwise specified.

[0066] Example 1

[0067] First, 32 g (0.28 mol) of allyl glycidyl ether and 14.4 g (0.06 mol) of tetramethylcyclotetrasiloxane (D4H, Sisbo organosilicon) were added to a three-necked flask. Then, 0.2 g of caster catalyst (platinum-divinyltetramethyldisiloxane complex) was added to the three-necked flask. The reaction was then continuously stirred mechanically and protected by a nitrogen flow. The reaction temperature was controlled at 90 °C and the reaction time was 6 hours. After the reaction was completed, the unreacted allyl glycidyl ether monomer was removed by vacuum distillation at 60 °C, finally yielding the hydrosilylation product of tetramethylcyclotetrasiloxane and allyl glycidyl ether.

[0068] Using the above hydrosilylation product as a reactant, 26.8 g (0.255 mol) of diethanolamine was added to a three-necked flask. The reaction temperature was controlled at 40 °C and the reaction time was 2 hours. After the reaction was completed, the unreacted diethanolamine was removed by vacuum distillation at 80 °C to obtain the star-shaped silane blocking agent of Example 1.

[0069] The star-shaped silane blocking agent prepared in Example 1 was characterized by structural analysis, including 1H NMR and 1C NMR spectra.

[0070] 1H-NMR (CDCl3, 400 MHz): δ3.85 (4H, dddd, J = 5.28, 5.28, 4.90, 4.90Hz), 3.44-3.60 (24H, 3.54 (dd, J = 2.67, 2.67 Hz), 3.54 (dd, J = 2.67, 2.67Hz), 3.50 (d, J = 5.28 Hz), 3.50 (d, J = 5.28 Hz)), 3.26-3.40 (8H, 3.33 (dd,J = 7.30, 7.30 Hz), 3.33 (dd, J = 7.30, 7.30 Hz)), 2.76-2.90 (24H, 2.84 (dd,J = 2.67, 2.67 Hz), 2.84 (dd, J = 2.67, 2.67 Hz), 2.82 (d, J = 4.90 Hz), 2.82(d, J = 4.90 Hz)), 1.84-2.02 (8H, 1.93 (dddd, J = 7.50, 7.50, 7.30, 7.30 Hz), 1.93 (dddd, J = 7.50, 7.50, 7.30, 7.30 Hz)), 0.90-1.04 (8H, 0.97 (dd, J =7.50, 7.50 Hz), 0.97 (dd, J = 7.50, 7.50 Hz)), 0.32 (12H, s).

[0071] 13C-NMR (CDCl3, 101 MHz): δ72.50 (4C, s), 70.94 (4C, s), 65.30 (4C,s), 59.47 (8C, s), 56.85 (4C, s), 55.89 (8C, s), 39.00 (4C, s), 29.40 (4C,s), 0.78 (4C,s).

[0072] Example 2

[0073] The preparation method of the hydrosilylation product of tetramethylcyclotetrasiloxane and allyl glycidyl ether is the same as in Example 1. The hydrosilylation product of tetramethylcyclotetrasiloxane and allyl glycidyl ether is used as the reactant. 34 g (0.255 mol) of diisopropanolamine is added to a three-necked flask. The reaction temperature is controlled at 50 °C and the reaction time is 3 hours. After the reaction is completed, the unreacted diisopropanolamine is removed by vacuum distillation at 90 °C to obtain the star-shaped silane blocking agent of Example 2.

[0074] Example 3

[0075] First, 3.73 g (0.02 mol) of 1,3-divinyltetramethyldisiloxane and 14.4 g (0.06 mol) of tetramethylcyclotetrasiloxane were added to a three-necked flask. Then, 0.1 g of Castells catalyst was added to the flask. The mixture was then continuously stirred mechanically and protected with a nitrogen flow. The reaction temperature was controlled at 80 °C and the reaction time was 3 hours. After the reaction was completed, the temperature was raised to 85 °C and 25.1 g (0.22 mol) of allyl glycidyl ether and 0.1 g of Castells catalyst were added dropwise over 0.5 hours. The temperature was then raised to 90 °C and the reaction was carried out for 8 hours. After the reaction was completed, the unreacted allyl glycidyl ether monomer was removed by vacuum distillation at 60 °C, finally yielding the hydrosilylation product of tetramethylcyclotetrasiloxane, divinyltetramethyldisiloxane, and allyl glycidyl ether.

[0076] Using the above hydrosilylation product as a reactant, 23.1 g (0.22 mol) of diethanolamine was added to a three-necked flask. The reaction temperature was controlled at 45 °C and the reaction time was 3 hours. After the reaction was completed, the unreacted diethanolamine was removed by vacuum distillation at 80 °C to obtain the star-shaped silane blocking agent of Example 3.

[0077] Example 4

[0078] The synthesis method of the hydrosilylation product of tetramethylcyclotetrasiloxane with divinyltetramethyldisiloxane and allyl glycidyl ether is the same as in Example 3. The above hydrosilylation product is used as the reactant. 29.3 g (0.22 mol) of diisopropanolamine is added to a three-necked flask. The reaction temperature is controlled at 55 °C and the reaction time is 4 hours. After the reaction is completed, the unreacted diisopropanolamine is removed by vacuum distillation at 90 °C to obtain the star-shaped silane blocking agent of Example 4.

[0079] Example 5

[0080] A water-based paint remover using a silane sealant, wherein the raw materials of the water-based paint remover include the following raw materials in weight percentages: 18% benzyl alcohol, 35% isophorone, 7% triethanolamine, 1.5% benzotriazole, 3.5% AEO-9 emulsifier, 7.5% sodium dodecylbenzenesulfonate, 5% star-shaped silane sealant prepared in Example 1, 1% polyacrylamide thickener, and the balance being water.

[0081] Example 6

[0082] A water-based paint remover using a silane sealant, wherein the raw materials of the water-based paint remover include the following raw materials in weight percentages: 18% benzyl alcohol, 35% ethyl lactate, 7% triisopropanolamine, 1.5% methylbenzotriazole, 5% cashew phenol polyoxyethylene ether, 7% sodium dodecylbenzenesulfonate, 5% star-shaped silane sealant prepared in Example 1, 1% polyacrylamide thickener, and the balance being water.

[0083] Example 7

[0084] A water-based paint remover using a silane sealant, wherein the raw materials of the water-based paint remover include the following raw materials in weight percentages: 18% benzyl alcohol, 35% isophorone, 7% triethanolamine, 1.5% benzotriazole, 3.5% AEO-9 emulsifier, 7.5% sodium dodecylbenzenesulfonate, 5% star-shaped silane sealant prepared in Example 2, 1% polyacrylamide thickener, and the balance being water.

[0085] Example 8

[0086] A water-based paint remover using a silane sealant, wherein the raw materials of the water-based paint remover include the following raw materials in weight percentages: 18% benzyl alcohol, 35% ethyl lactate, 7% triisopropanolamine, 1.5% methylbenzotriazole, 5% cashew phenol polyoxyethylene ether, 7% sodium dodecylbenzenesulfonate, 5% star-shaped silane sealant prepared in Example 2, 1% polyacrylamide thickener, and the balance being water.

[0087] Example 9

[0088] A water-based paint remover using a silane sealant, wherein the raw materials of the water-based paint remover include the following raw materials in weight percentages: 18% benzyl alcohol, 35% isophorone, 7% triethanolamine, 1.5% benzotriazole, 3.5% AEO-9 emulsifier, 7.5% sodium dodecylbenzenesulfonate, 3.5% star-shaped silane sealant prepared in Example 3, 1% polyacrylamide thickener, and the balance being water.

[0089] Example 10

[0090] A water-based paint remover using a silane sealant, wherein the raw materials of the water-based paint remover include the following raw materials in weight percentages: 18% benzyl alcohol, 35% ethyl lactate, 7% triisopropanolamine, 1.5% methylbenzotriazole, 5% cashew phenol polyoxyethylene ether, 7% sodium dodecylbenzenesulfonate, 3.5% star-shaped silane sealant prepared in Example 3, 1% polyacrylamide thickener, and the balance being water.

[0091] Example 11

[0092] A water-based paint remover using a silane sealant, wherein the raw materials of the water-based paint remover include the following raw materials in weight percentages: 18% benzyl alcohol, 35% isophorone, 5% triethanolamine, 1.5% benzotriazole, 3.5% AEO-9 emulsifier, 7.5% sodium dodecylbenzenesulfonate, 3.5% star-shaped silane sealant prepared in Example 4, 1% polyacrylamide thickener, and the balance being water.

[0093] Example 12

[0094] A water-based paint remover using a silane sealant, wherein the raw materials of the water-based paint remover include the following raw materials in weight percentages: 18% benzyl alcohol, 35% ethyl lactate, 7% triisopropanolamine, 1.5% methylbenzotriazole, 5% cashew phenol polyoxyethylene ether, 7% sodium dodecylbenzenesulfonate, 3.5% star-shaped silane sealant prepared in Example 4, 1% polyacrylamide thickener, and the balance being water.

[0095] Comparative Example 1

[0096] A water-based paint remover using silane sealants, wherein the raw materials of the water-based paint remover include the following raw materials in weight percentages: 18% benzyl alcohol, 35% isophorone, 7% triisopropanolamine, 1.5% methylbenzotriazole, 5% cashew phenol polyoxyethylene ether, 7% sodium dodecylbenzenesulfonate, 3.5% PMX-200 polydimethylsiloxane silicone oil (Dow Chemical, kinematic viscosity 200 cSt), 1% polyacrylamide thickener, and the balance being water.

[0097] The preparation method of the above water-based paint remover is as follows: The star-shaped silane sealant in the formula is mixed evenly with alcohol solvent, ketone or ester solvent, organic base and corrosion inhibitor at room temperature to obtain the oil phase component; the anionic surfactant, nonionic surfactant and polyacrylamide thickener in the formula are dissolved in water and mixed evenly at room temperature to obtain the aqueous phase component; the aqueous phase component is dispersed using a high-speed disperser at a speed of 1000 rpm, and the oil phase component is poured into it during the dispersion process. After the oil phase component is added, the dispersion is continued at a speed of 1000 rpm for 30 minutes to obtain the corresponding water-based paint remover.

[0098] Test section

[0099] Using 150×70×0.8mm 3004 aluminum alloy test pieces conforming to ISO 17872:2007 standards, holes were drilled 12mm from the top edge, epoxy coating was applied, and after full curing, the pieces were left to stand for 7 days before paint removal. The specific paint removal method involved immersing the epoxy-coated aluminum alloy test pieces in different types of water-based paint removers at 70°C and 90°C, respectively, while simultaneously using 40kHz ultrasonic vibration to assist in paint removal. The initial bubbling time and complete peeling time of the paint film, as well as the mass loss per unit area before and after paint removal, were recorded.

[0100] The results of the above tests are recorded in Table 1.

[0101] Table 1

[0102]

[0103] The test results recorded in Table 1 show that the star-shaped silane sealant consists of a cyclic polysiloxane core and polyol side arms. In Examples 5-12, the silane sealant was added to the paint remover to form hydrogen bonds with alcohols, ketones, and esters, preventing them from volatilizing and becoming ineffective during the paint removal process, thus enhancing the penetration of the paint film, shortening the paint removal time, and increasing the paint removal speed of the paint remover. The paint remover of Examples 5-12 showed a shorter paint removal time for the epoxy paint film on the aluminum alloy surface, while Comparative Example 1, which used polydimethyl silicone oil as a sealant, showed a significantly longer paint removal time, especially at higher temperatures, where the difference in paint removal speed compared to Examples 5-12 was obvious.

[0104] On the other hand, the sealant can also prevent pitting or corrosion of the aluminum alloy during the paint stripping process. Aluminum alloys are particularly sensitive to alkalis, and paint strippers containing alkaline amine compounds inevitably cause slight corrosion of the metal substrate, leading to the dissolution of metal ions. The hydroxyl groups in the sealant can chelate these metal ions, preventing them from depositing on the aluminum alloy surface and forming galvanic cells that cause pitting corrosion. The same trend can be seen in the unit area mass loss of the aluminum alloy specimens in Examples 5-12 and Comparative Example 1.

[0105] Finally, it should be noted that the above-described embodiments are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the patent application. It should be pointed out that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Furthermore, it should be understood that after reading the above teachings of this application, those skilled in the art can make various alterations or modifications to this application, and the equivalent forms obtained also fall within the scope of protection of this application. It should also be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A star-shaped silane blocking agent, characterized in that, Star-shaped silane blocking agents have a polysiloxane core and side arms containing polyols, wherein the star-shaped silane blocking agents include those with the general structural formula [insert structural formula here]. , Compounds or mixtures of both; Wherein, R1 is selected from methyl or phenyl, and R2 is a side arm containing a polyol, the side arm containing... or Structure; R3 is a hydrocarbon group with 1 to 12 carbon atoms; R4 and R5 may be the same or different, and are independently selected from methyl or phenyl; m and n are positive integers greater than or equal to 1.

2. The method for preparing the star-shaped silane blocking agent as described in claim 1, characterized in that, A monomer containing vinyl and epoxy groups is subjected to a hydrosilylation reaction with a hydrogen-containing silane cyclic compound to obtain an addition product. Then, an alkanolamine compound is used to react with the addition product to obtain a star-shaped silane blocking agent.

3. The method for preparing the star-shaped silane blocking agent according to claim 2, characterized in that, The preparation method also includes: performing a hydrosilylation reaction between a vinyl-terminated polysiloxane and a hydrogen-containing silane cyclic compound, and then performing a hydrosilylation reaction between the polysiloxane and a monomer containing vinyl and epoxy groups to obtain the addition product; And / or, the monomer containing vinyl and epoxy groups is selected from one or more combinations of allyl glycidyl ether, 4-vinylphenyl glycidyl ether, 4-vinylbenzyl glycidyl ether, 4-vinyl-1-cyclohexene-1,2-epoxy, glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexyl acrylate and 3,4-epoxycyclohexyl methacrylate; And / or, the alkanolamine compound is selected from one or a combination of two of diethanolamine and diisopropanolamine; And / or, in the hydrosilylation reaction, the molar ratio of silane groups (Si-H) in the hydrogen-containing silane ring to vinyl groups (C=C) in the vinyl-terminated polysiloxane is (4-8):1; And / or, in the hydrosilylation reaction, the molar ratio of silane groups (Si-H) in the hydrogen-containing silane ring to vinyl groups (C=C) in the monomer containing vinyl and epoxy groups is 1:(1.0-1.3).

4. The method for preparing the star-shaped silane blocking agent according to claim 2, characterized in that, In hydrosilylation reactions, platinum complexes are also used as reaction catalysts; The platinum complex is selected from one or more combinations of platinum-isopropanol complex catalysts, platinum-ene complex catalysts, platinum-phosphine amine complex catalysts, and platinum-(N-heterocyclic carbene) complexes. And / or, in hydrosilylation reactions, the amount of platinum complex used is 0.08-0.8 wt% of the total reactants; And / or, after the hydrosilylation reaction is completed, excess unreacted monomers containing vinyl and epoxy groups are removed by vacuum distillation; And / or, after the reaction of the alkanolamine with the addition product is complete, excess unreacted alkanolamine may be removed by vacuum distillation; And / or, during the hydrosilylation reaction, either nitrogen or an inert gas is continuously introduced.

5. The use of the star-shaped silane sealant as described in claim 1 in paint remover.

6. A water-based paint remover, characterized in that, Water-based paint removers include: Alcohol solvents, ketone or ester solvents, basic activators, thickeners, the star-shaped silane blocking agent as described in claim 1, corrosion inhibitors, anionic surfactants, nonionic surfactants, and water; The alcohol solvent is selected from alcohols with a boiling point ≥100℃ at normal pressure; The ketone or ester solvents are selected from ketones or esters with a boiling point ≥100℃ at normal pressure; The alkaline activator is selected from one or more combinations of monoethanolamine, isopropanolamine, diethanolamine, diisopropanolamine, triethanolamine, triisopropanolamine and hexamethylenetetramine; The thickener is selected from one or more combinations of sodium polyacrylate, polyvinyl alcohol, polyacrylamide, and sodium carboxymethyl cellulose; The corrosion inhibitor is selected from one or a combination of two of benzotriazole and methylbenzotriazole; The anionic surfactant is selected from one or a combination of two of sulfate surfactants and sulfonate surfactants; The nonionic surfactant is selected from one or more combinations of fatty alcohol polyoxyethylene ethers, isomeric alcohol ethers, alkyl glycosides, and cashew phenol polyoxyethylene ethers.

7. The water-based paint remover according to claim 6, characterized in that, Water-based paint remover comprises the following raw materials by weight percentage: 10-30% alcohol solvent, 25-40% ketone or ester solvent, 1-10% alkaline activator, 1-5% corrosion inhibitor, 1-5% sealing agent, 1-10% anionic surfactant, 1-5% nonionic surfactant, 0.1-3% thickener, balance water.

8. A method for preparing the water-based paint remover according to any one of claims 6-7, comprising: The sealing agent, alcohol solvent, ketone or ester solvent, corrosion inhibitor and alkaline activator are stirred evenly at room temperature to obtain the oil phase component; the anionic surfactant, nonionic surfactant, thickener and water are stirred evenly at room temperature to obtain the aqueous phase component; the oil phase component is added to the aqueous phase component at a speed of 100-1500 rpm, and after the addition is complete, the mixture is kept dispersed for 10-60 minutes to obtain the water-based paint remover.

9. A method for removing organic paint film from the surface of aluminum or aluminum alloy, comprising: An aluminum or aluminum alloy with an organic paint film on its surface is immersed in the water-based paint remover according to any one of claims 6-7 at a certain temperature, wherein the temperature is room temperature to 100°C.

10. The use of the water-based paint remover according to any one of claims 6-7 in the paint removal of waste aluminum cans.

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