Paint remover and preparation method thereof

Abstract

The embodiment of the invention provides a paint remover and a preparation method thereof. The paint remover comprises the following raw materials: an alcohol solvent, an ester solvent, an activator, a cosolvent, a corrosion inhibitor, a surfactant, a cosurfactant and deionized water. The paint remover is environment-friendly, does not need special temperature conditions in the preparation and use processes, and has high efficiency, stability, safety and universality.

Description

Technical Field

[0001] The present application relates to the technical field of paint strippers, and in particular to a paint stripper and a preparation method thereof. Background Art

[0002] In order to improve the service stability of steel, it is usually necessary to perform a hot-dip plastic coating treatment on the surface of the steel. However, when the steel treated with the hot-dip plastic coating needs to be recycled, the hot-dip plastic coating needs to be cleaned off.

[0003] Hot-dip coatings can include polyethylene (PE) coatings or composite coatings of epoxy resin (EP) and polyvinyl chloride (PVC). Immersing the coating in a paint stripper can improve the cleaning effect of hot-dip coatings. However, the composition of existing paint strippers is not perfect, making the preparation and use conditions of paint strippers relatively stringent, reducing their universal applicability. Summary of the Invention

[0004] The embodiments of the present application provide a paint stripper and a preparation method thereof to solve the problem that the component configuration of the existing paint stripper is not perfect, which makes the preparation conditions and use conditions of the paint stripper relatively harsh and reduces the universality of the paint stripper.

[0005] In a first aspect, an embodiment of the present application provides a paint stripper, comprising the following raw materials:

[0006] Alcohol solvents, ester solvents, activators, co-solvents, corrosion inhibitors, surfactants, co-surfactants, deionized water.

[0007] In one possible embodiment, the raw materials include the following raw materials in weight percentage:

[0008] 20%-65% alcohol solvent, 5%-20% co-solvent, 5%-30% ester solvent, 1%-10% activator, 1%-5% corrosion inhibitor, 1%-15% surfactant, 1%-5% co-surfactant, and the balance is deionized water.

[0009] In a possible implementation manner, the raw material further includes a thickener.

[0010] In one possible embodiment, the raw materials include the following raw materials in weight percentage:

[0011] 20%-45% alcohol solvent, 5%-20% co-solvent, 5%-30% ester solvent, 1%-10% activator, 1%-10% thickener, 1%-5% corrosion inhibitor, 1%-15% surfactant, 1%-5% co-surfactant, and the balance is deionized water.

[0012] In one possible embodiment, the raw materials include the following raw materials in weight percentage:

[0013] 30% alcohol solvent, 12% co-solvent, 17% ester solvent, 5% activator, 1.5% thickener, 4% corrosion inhibitor, 7.5% surfactant, 3% co-surfactant, and the balance is deionized water.

[0014] In one possible embodiment, the alcohol solvent includes one or more of methanol, ethanol, isopropanol, n-butanol, tert-butanol, isobutanol, cyclohexanol, benzyl alcohol, phenylethyl alcohol, diethanol, propylene glycol, glycerol, and pentaerythritol; preferably, the alcohol solvent includes one or more of benzyl alcohol and phenylethyl alcohol.

[0015] In one possible embodiment, the ester solvent includes one or more of ethyl acetate, butyl acetate, ethyl lactate, dimethyl carbonate, ethyl formate, isobutyl formate, isoamyl formate, methyl acetate, n-butyl acetate, amyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, propyl propionate, and n-butyl lactate; preferably, the ester solvent includes dimethyl carbonate.

[0016] In one possible embodiment, the surfactant includes one or more of sodium stearate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, cetyltrimethylammonium bromide, dodecyldimethyl betaine, N-acyl glutamate, AEO-9, OP-10, Span 80, Tween 80, and Tween 20; preferably, the surfactant includes one or more of OP-10 and Span 80.

[0017] In one possible embodiment, the co-surfactant includes one or more of polyethylene glycol ether, dodecyldimethylamine, n-butanol, triethanolamine oleate, sodium polyacrylate, sodium xylene sulfonate, sodium benzoate, sodium tripolyphosphate, sodium carbonate, sodium sulfate, and borax; preferably, the co-surfactant includes one or more of polyethylene glycol ether and sodium tripolyphosphate.

[0018] In one possible embodiment, the thickener includes one or more of sodium polyacrylate, polyvinyl alcohol, polyacrylamide, sodium hydroxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, aluminum silicate, sodium chloride, pectin, and agar; preferably, the thickener includes one or more of sodium hydroxymethyl cellulose, hydroxyethyl cellulose, and sodium chloride.

[0019] In one possible embodiment, the corrosion inhibitor includes one or more of sodium silicate, sodium metasilicate pentahydrate, potassium silicate, benzotriazole, tolutriazole, monoethanolamine, diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, dodecylamine, hexamethylenetetramine, and polyvinyl butyral; preferably, the corrosion inhibitor includes one or more of dodecylamine and hexamethylenetetramine.

[0020] In one possible embodiment, the activator includes an acidic activator and a basic activator; preferably, the activator is an acidic activator.

[0021] Wherein, the acidic activator includes one or more of phenol, hydrogen peroxide, formic acid, and acetic acid; the alkaline activator includes one or more of ethanolamine, diethanolamine, triethanolamine, sodium hydroxide, and potassium hydroxide;

[0022] Preferably, the acidic activator includes one or more of formic acid and acetic acid.

[0023] In one possible embodiment, the cosolvent includes one or more of methanol, ethanol, propylene glycol, ethylene glycol monomethyl ether, urea, isopropanol, 3-methoxy-3-methyl-1-butanol, dimethyl sulfoxide, ethyl acetate, and acetone; preferably, the cosolvent includes one or more of ethylene glycol monomethyl ether, isopropanol, and ethanol.

[0024] In one possible embodiment, the raw materials include the following raw materials in weight percentage:

[0025] 30% benzyl alcohol, 12% isopropyl alcohol, 17% dimethyl carbonate, 5% methanol, 1.5% sodium chloride, 4% hexamethylenetetramine, 7.5% OP-10, 3% sodium tripolyphosphate, and the balance is deionized water.

[0026] In one possible embodiment, the paint stripper is a microemulsion.

[0027] In one possible embodiment, the particle size of the microemulsion is 10-100 nm.

[0028] In a second aspect, the present invention provides a method for preparing a paint stripper, comprising the following steps:

[0029] preparing an aqueous phase solvent and an oil phase solvent;

[0030] Adding an aqueous solvent to an oily solvent, stirring uniformly to obtain an emulsion, and adding a cosolvent to the emulsion to obtain a paint stripper;

[0031] The aqueous phase solvent includes deionized water dissolved with a co-surfactant; and the oil phase solvent includes a mixed solution of an alcohol solvent, an ester solvent, an activator, a surfactant and a corrosion inhibitor.

[0032] In one possible embodiment, the preparation method of the aqueous solvent includes:

[0033] The co-surfactant is added into deionized water and stirred to obtain an aqueous phase solvent.

[0034] In one possible embodiment, the method for preparing the oil phase solvent includes:

[0035] An alcohol solvent, an ester solvent, an activator, a surfactant and a corrosion inhibitor are stirred to obtain an oil phase solvent.

[0036] In one possible implementation, the method further includes:

[0037] Add a cosolvent to the emulsion.

[0038] In one possible embodiment, the stirring temperature is lower than 40°C.

[0039] The paint stripper and preparation method thereof provided in the embodiments of the present application mainly include alcohol solvents, ester solvents, activators, thickeners, corrosion inhibitors, surfactants, co-surfactants and deionized water. The above solvents are all environmentally friendly solvents and are environmentally friendly. Moreover, the preparation and use processes do not require special temperature conditions and are highly efficient, stable, safe and universal. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0041] Figure 1 Schematic diagram of the process for preparing the paint stripper in the embodiment of the present application;

[0042] Figure 2 This is a picture of a paint stripper being used to remove paint from a component to be stripped, corresponding to Example 1 of the present application;

[0043] Figure 3 Pictures of paint stripping components to be stripped using paint strippers corresponding to Examples 1-5 and Comparative Example 1 of the present application;

[0044] Figure 4 This is the particle size distribution diagram of the microemulsion of the paint stripper corresponding to Example 1 of the present application.

[0045] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0046] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0047] The existing environmentally friendly paint stripper preparation method includes:

[0048] (1) Benzyl alcohol, ethyl acetate, N-methyl pyrrolidone, ethylene glycol anisole, and styrene-modified liquid paraffin were mixed uniformly to obtain material A;

[0049] (2) Add nano-SiO2 aqueous dispersion, surfactant, and thickener into water and mix evenly to obtain material B;

[0050] (3) Mix the material A and the material B evenly to obtain the environmentally friendly paint stripper.

[0051] However, this method has the following problems:

[0052] (1) The styrene-modified liquid paraffin and the polyethyleneimine-modified nano-SiO2 aqueous dispersion in this product require additional configuration, and the reaction is complex. The preparation process involves high-temperature operation, making it difficult to industrialize.

[0053] (2) One of the main solvents used in this product is ethyl acetate, which is highly volatile and easily causes solvent loss, and has poor compatibility with other additives.

[0054] (3) The product formula does not contain an activator, which is not conducive to the penetration of solvents into the paint film, and the paint stripping rate will be greatly reduced.

[0055] (4) This product formula does not contain corrosion inhibitors, which may affect the quality and service life of the substrate.

[0056] (5) The operating temperature of this product is 40℃, and it needs to be heated. The energy consumption is relatively high and the risk factor will increase due to high temperature conditions.

[0057] In combination with the above scenarios, it can be seen that in the prior art, the preparation and use processes of paint strippers are subject to certain restrictions, such as high temperature conditions, which poses a technical problem of reducing the universality of paint strippers.

[0058] The paint stripper provided in the present application uses a solvent mixture that does not require high temperature conditions during the preparation process to obtain a mixed solvent that can achieve a paint stripping effect under room temperature conditions, thereby solving the technical problem of low universality of existing paint strippers.

[0059] The following describes in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems using specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The following describes the embodiments of the present application.

[0060] The present application provides a paint stripper, comprising the following raw materials:

[0061] Alcohol solvents, ester solvents, activators, co-solvents, corrosion inhibitors, surfactants, co-surfactants, deionized water.

[0062] The above raw materials are in the following weight percentages:

[0063] 20%-65% alcohol solvent, 5%-30% ester solvent, 1%-10% activator, 5%-20% co-solvent, 1%-5% corrosion inhibitor, 1%-15% surfactant, 1%-5% co-surfactant, and the balance is deionized water.

[0064] Illustratively, among the above raw materials, the alcohol solvent includes one or more of methanol, ethanol, isopropanol, n-butanol, tert-butanol, isobutanol, cyclohexanol, benzyl alcohol, phenylethyl alcohol, diethanol, propylene glycol, glycerol, and pentaerythritol; preferably, the alcohol solvent includes one or more of benzyl alcohol and phenylethyl alcohol.

[0065] The ester solvent includes one or more of ethyl acetate, butyl acetate, ethyl lactate, dimethyl carbonate, ethyl formate, isobutyl formate, isoamyl formate, methyl acetate, n-butyl acetate, amyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, propyl propionate, and n-butyl lactate; preferably, the ester solvent includes dimethyl carbonate.

[0066] The cosolvent includes one or more of methanol, ethanol, propylene glycol, ethylene glycol monomethyl ether, urea, isopropanol, 3-methoxy-3-methyl-1-butanol, dimethyl sulfoxide, ethyl acetate, and acetone; preferably, the cosolvent includes one or more of ethylene glycol monomethyl ether, isopropanol, and ethanol.

[0067] The surfactant includes one or more of sodium stearate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, cetyltrimethylammonium bromide, dodecyldimethylbetaine, N-acylglutamate, AEO-9, OP-10, Span 80, Tween 80, and Tween 20; preferably, the surfactant includes one or more of OP-10 and Span 80.

[0068] The co-surfactant includes one or more of polyethylene glycol ether, dodecyldimethylamine, n-butanol, triethanolamine oleate, sodium polyacrylate, sodium xylene sulfonate, sodium benzoate, sodium tripolyphosphate, sodium carbonate, sodium sulfate, and borax; preferably, the co-surfactant includes one or more of polyethylene glycol ether and sodium tripolyphosphate.

[0069] The corrosion inhibitor includes one or more of sodium silicate, sodium metasilicate pentahydrate, potassium silicate, benzotriazole, tolutriazole, monoethanolamine, diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, dodecylamine, hexamethylenetetramine, and polyvinyl butyral; preferably, the corrosion inhibitor includes one or more of dodecylamine and hexamethylenetetramine.

[0070] The activator includes an acidic activator and an alkaline activator; preferably, the activator is an acidic activator.

[0071] The acidic activator includes one or more of phenol, hydrogen peroxide, formic acid, and acetic acid; the alkaline activator includes one or more of ethanolamine, diethanolamine, triethanolamine, sodium hydroxide, and potassium hydroxide;

[0072] Preferably, the acidic activator includes one or more of formic acid and acetic acid.

[0073] The present application also provides a paint stripper, comprising the following raw materials:

[0074] Alcohol solvents, ester solvents, activators, thickeners, corrosion inhibitors, surfactants, co-surfactants, co-solvents, deionized water.

[0075] Among them, the thickener includes one or more of sodium polyacrylate, polyvinyl alcohol, polyacrylamide, sodium hydroxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, aluminum silicate, sodium chloride, pectin, and agar; preferably, the thickener includes one or more of sodium hydroxymethyl cellulose, hydroxyethyl cellulose, and sodium chloride.

[0076] The above raw materials are in the following weight percentages:

[0077] 20%-45% alcohol solvent, 5%-20% co-solvent, 5%-30% ester solvent, 1%-10% activator, 1%-10% thickener, 1%-5% corrosion inhibitor, 1%-15% surfactant, 1%-5% co-surfactant, and the balance is deionized water.

[0078] More specifically, the raw materials used include the following raw materials in weight percentage:

[0079] 30% alcohol solvent, 12% co-solvent, 17% ester solvent, 5% activator, 1.5% thickener, 4% corrosion inhibitor, 7.5% surfactant, 3% co-surfactant, and the balance is deionized water.

[0080] Illustratively, among the above raw materials, the alcohol solvent includes one or more of methanol, ethanol, isopropanol, n-butanol, tert-butanol, isobutanol, cyclohexanol, benzyl alcohol, phenylethyl alcohol, diethanol, propylene glycol, glycerol, and pentaerythritol; preferably, the alcohol solvent includes one or more of benzyl alcohol and phenylethyl alcohol.

[0081] The ester solvent includes one or more of ethyl acetate, butyl acetate, ethyl lactate, dimethyl carbonate, ethyl formate, isobutyl formate, isoamyl formate, methyl acetate, n-butyl acetate, amyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, propyl propionate, and n-butyl lactate; preferably, the ester solvent includes dimethyl carbonate.

[0082] The surfactant includes one or more of sodium stearate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, cetyltrimethylammonium bromide, dodecyldimethylbetaine, N-acylglutamate, AEO-9, OP-10, Span 80, Tween 80, and Tween 20; preferably, the surfactant includes one or more of OP-10 and Span 80.

[0083] The co-surfactant includes one or more of polyethylene glycol ether, dodecyldimethylamine, n-butanol, triethanolamine oleate, sodium polyacrylate, sodium xylene sulfonate, sodium benzoate, sodium tripolyphosphate, sodium carbonate, sodium sulfate, and borax; preferably, the co-surfactant includes one or more of polyethylene glycol ether and sodium tripolyphosphate.

[0084] The thickener includes one or more of sodium polyacrylate, polyvinyl alcohol, polyacrylamide, sodium hydroxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, aluminum silicate, sodium chloride, pectin, and agar; preferably, the thickener includes one or more of sodium hydroxymethyl cellulose, hydroxyethyl cellulose, and sodium chloride.

[0085] The corrosion inhibitor includes one or more of sodium silicate, sodium metasilicate pentahydrate, potassium silicate, benzotriazole, tolutriazole, monoethanolamine, diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, dodecylamine, hexamethylenetetramine, and polyvinyl butyral; preferably, the corrosion inhibitor includes one or more of dodecylamine and hexamethylenetetramine.

[0086] The activator includes an acidic activator and an alkaline activator; preferably, the activator is an acidic activator.

[0087] Among them, the acidic activator includes one or more of phenol, hydrogen peroxide, formic acid, and acetic acid; the alkaline activator includes one or more of ethanolamine, diethanolamine, triethanolamine, sodium hydroxide, and potassium hydroxide; preferably, the acidic activator includes one or more of formic acid and acetic acid.

[0088] The cosolvent includes one or more of methanol, ethanol, propylene glycol, ethylene glycol monomethyl ether, urea, isopropanol, 3-methoxy-3-methyl-1-butanol, dimethyl sulfoxide, ethyl acetate, and acetone; preferably, the cosolvent includes one or more of ethylene glycol monomethyl ether, isopropanol, and ethanol.

[0089] In one possible embodiment, the raw material composition of the paint stripper adopts the following weight percentages:

[0090] 30% alcohol solvent, 12% co-solvent, 17% ester solvent, 5% activator, 1.5% thickener, 4% corrosion inhibitor, 7.5% surfactant, 3% co-surfactant, and the balance is deionized water.

[0091] Optionally, 30% benzyl alcohol, 12% isopropyl alcohol, 17% dimethyl carbonate, 5% methanol, 1.5% sodium chloride, 4% hexamethylenetetramine, 7.5% OP-10, 3% sodium tripolyphosphate, and the balance is deionized water.

[0092] Sodium tripolyphosphate (STP) in this formulation provides dispersing and emulsifying, sustained-release, auxiliary cleaning, and complexing properties. This multifunctional component simplifies the formulation and helps disperse pigments, resins, and other components that have been removed from the paint layer, preventing them from reaggregating and settling. STP also works synergistically with other ingredients in the paint stripper, resulting in a cleaner surface after application. STP also adsorbs at the oil-water interface, forming a protective film that promotes the formation and stability of the microemulsion.

[0093] This technology prepares a microemulsion paint stripper as a semi-aqueous paint stripper, using water as an important component of the formula, reducing the use of harmful solvents, and does not contain highly volatile and toxic solvents such as dichloromethane and phenol. It retains the advantages of strong elution ability and high safety of semi-aqueous paint strippers, and solves the problem that semi-aqueous paint strippers are easy to stratify and difficult to store, overcoming the shortcomings of solvent-based paint strippers such as insufficient safety.

[0094] In addition, the solvents in this technology are replaced by some ester compounds, which have high boiling points, pleasant aromas, and relatively little harm to humans and the environment. Dimethyl carbonate is an environmentally friendly solvent that is easily biodegradable and widely used in medicine, pesticides, spices, coatings, etc. It can dissolve liquid and solid resins and is suitable for preparing paint strippers for cleaning PVC paints and multi-layer mixed coatings and other difficult-to-remove coatings. However, dimethyl carbonate is highly hydrophobic and not very compatible with some solvents, which can easily lead to instability and stratification of the prepared paint strippers. Therefore, it is rarely used in paint stripper formulations. This technology can be scientifically compounded so that each component can retain its excellent performance and meet the characteristics of high storage stability and no stratification.

[0095] Figure 1 Schematic diagram of the process for preparing the paint stripper in the embodiment of this application. Figure 1 As shown, the method includes:

[0096] S101. Prepare an aqueous phase solvent and an oil phase solvent.

[0097] The aqueous phase solvent is obtained by adding a thickener and a co-surfactant into deionized water and stirring, and the oil phase solvent is obtained by stirring an alcohol solvent, an ester solvent, an activator, a surfactant and a corrosion inhibitor.

[0098] For example, 1%-10% thickener and 1%-5% co-surfactant are added to 10%-40% deionized water, and stirred and dissolved at room temperature at a stirring rate of 100-800 rpm.

[0099] Specifically, the normal temperature in the embodiments of the present application refers to an ambient temperature less than 40°C, preferably, the ambient temperature is between 20°C and 25°C.

[0100] 20%-50% of alcohol solvent, 5%-30% of ester solvent, 1%-10% of activator, 1%-15% of surfactant and 1%-5% of corrosion inhibitor are stirred evenly at room temperature at a stirring rate of 100-800 rpm until the mixture is evenly mixed.

[0101] S102, mixing the aqueous phase solvent and the oil phase solvent, and stirring evenly to obtain an emulsion.

[0102] Specifically, the order of mixing the aqueous solvent and the oily solvent is not particularly limited, and the aqueous solvent can be added to the oily solvent for mixing, or the oily solvent can be added to the aqueous solvent for mixing.

[0103] The aqueous phase solvent is deionized water dissolved with a co-surfactant; the oil phase solvent is a mixed solution of an alcohol solvent, an ester solvent, an activator, a surfactant and a corrosion inhibitor.

[0104] Optionally, the aqueous phase solvent is deionized water in which a co-surfactant and a thickener are dissolved.

[0105] For example, add the aqueous phase solvent to the oil phase solvent, stir and mix at room temperature to form an emulsion, and the stirring rate is 100~800rpm.

[0106] S103, adding a co-solvent dropwise to the emulsion to obtain a paint stripper.

[0107] The cosolvent is present in a relatively small amount relative to the emulsion. To better disperse the emulsion into a microemulsion, the cosolvent needs to be slowly added dropwise while stirring to disperse the cosolvent in the emulsion and form a microemulsion. The slow addition rate is 10-60 drops per minute.

[0108] For example, 5% to 20% of a cosolvent is slowly added dropwise to the emulsion until the emulsion changes from milky white to translucent or transparent, thereby forming a microemulsion and obtaining a paint stripper.

[0109] The paint stripper is a microemulsion, and the particle size of the microemulsion is 10-100 nm.

[0110] Therefore, the solution of the present application can prepare a microemulsion paint stripper with a unique particle size. When the paint film is immersed in the microemulsion, the large number of submicropores and defects on the inner and outer surfaces of the paint film are more likely to absorb solvents. The paint stripper quickly diffuses and penetrates through molecular thermal motion, forming a regular directional adsorption arrangement layer at the large number of submicropores and defects on the inner and outer surfaces of the paint film. Various forces between molecules work together to exert a pulling and stretching effect on the surface of the paint film that is opposite to the adhesion force, causing the paint film to expand rapidly and quickly peel off its adhesive surface. The microemulsion paint stripper prepared by this technology is a tiny droplet formed by an oil-water mixture, and the formed emulsion is stable and does not stratify. This stable structure makes the microemulsion paint stripper more stable when volatilizing, thereby reducing volatility.

[0111] The paint stripper of the above application is prepared through several specific examples below.

[0112] Example 1

[0113] Step 1: Prepare the aqueous solvent.

[0114] Add 1.5% NaCl (thickener) and 3% sodium tripolyphosphate (co-surfactant) to 20% deionized water, stir and dissolve at room temperature with a stirring rate of 100~800rpm.

[0115] Step 2: Prepare the oil phase solvent.

[0116] Stir 30% benzyl alcohol (alcohol solvent), 17% dimethyl carbonate (ester solvent), 5% formic acid (activator), 7.5% OP-10 (surfactant) and 4% hexamethylenetetramine (corrosion inhibitor) at room temperature at a stirring rate of 100-800 rpm until uniformly mixed.

[0117] Step 3: Prepare an oil-water mixed solvent.

[0118] Add the aqueous solution of step 1 to the oil phase of step 2, and stir at room temperature to form an emulsion at a stirring rate of 100-800 rpm.

[0119] Step 4: Preparation of microemulsion.

[0120] Isopropyl alcohol (cosolvent) was slowly added dropwise to the emulsion prepared in step 3 until the emulsion turned from milky white to transparent, thereby forming a microemulsion.

[0121] Example 2

[0122] Step 1: Prepare the aqueous solvent.

[0123] Add 1.5% NaCl (thickener) and 3% sodium tripolyphosphate (co-surfactant) to 20% deionized water, stir and dissolve at room temperature with a stirring rate of 100~800rpm.

[0124] Step 2: Prepare the oil phase solvent.

[0125] Stir 30% benzyl alcohol (alcohol solvent), 17% dimethyl carbonate (ester solvent), 5% NaOH (activator), 7.5% OP-10 (surfactant) and 4% hexamethylenetetramine (corrosion inhibitor) at room temperature at a stirring rate of 100-800 rpm until uniformly mixed.

[0126] Step 3: Prepare an oil-water mixed solvent.

[0127] Add the aqueous solution of step 1 to the oil phase of step 2, and stir at room temperature to form an emulsion at a stirring rate of 100-800 rpm.

[0128] Step 4: Preparation of microemulsion.

[0129] Isopropyl alcohol (cosolvent) was slowly added dropwise to the emulsion prepared in step 3 until the emulsion turned from milky white to transparent, thereby forming a microemulsion.

[0130] Example 3

[0131] Step 1: Prepare the aqueous solvent.

[0132] Add 1.5% NaCl (thickener) and 3% sodium tripolyphosphate (co-surfactant) to 20% deionized water, stir and dissolve at room temperature with a stirring rate of 100~800rpm.

[0133] Step 2: Prepare the oil phase solvent.

[0134] Stir 30% benzyl alcohol (alcohol solvent), 17% dimethyl carbonate (ester solvent), 5% ethanolamine (activator), 7.5% OP-10 (surfactant) and 4% hexamethylenetetramine (corrosion inhibitor) at room temperature at a stirring rate of 100-800 rpm until uniformly mixed.

[0135] Step 3: Prepare an oil-water mixed solvent.

[0136] Add the aqueous solution of step 1 to the oil phase of step 2, and stir at room temperature to form an emulsion at a stirring rate of 100-800 rpm.

[0137] Step 4: Preparation of microemulsion.

[0138] Isopropyl alcohol (cosolvent) was slowly added dropwise to the emulsion prepared in step 3 until the emulsion turned from milky white to transparent, thereby forming a microemulsion.

[0139] Example 4

[0140] Step 1: Prepare the aqueous solvent.

[0141] Add 1.5% NaCl (thickener) and 3% sodium tripolyphosphate (co-surfactant) to 20% deionized water, stir and dissolve at room temperature with a stirring rate of 100~800rpm.

[0142] Step 2: Prepare the oil phase solvent.

[0143] Stir 30% benzyl alcohol (alcohol solvent), 17% ethyl acetate (ester solvent), 5% formic acid (activator), 7.5% OP-10 (surfactant) and 4% hexamethylenetetramine (corrosion inhibitor) at room temperature at a stirring rate of 100-800 rpm until uniformly mixed.

[0144] Step 3: Prepare an oil-water mixed solvent.

[0145] Add the aqueous solution of step 1 to the oil phase of step 2, and stir at room temperature to form an emulsion at a stirring rate of 100-800 rpm.

[0146] Step 4: Preparation of microemulsion.

[0147] Isopropyl alcohol (cosolvent) was slowly added dropwise to the emulsion prepared in step 3 until the emulsion turned from milky white to transparent, thereby forming a microemulsion.

[0148] Example 5

[0149] Step 1: Prepare the aqueous solvent.

[0150] Add 1.5% NaCl (thickener) and 3% sodium tripolyphosphate (co-surfactant) to 20% deionized water, stir and dissolve at room temperature with a stirring rate of 100~800rpm.

[0151] Step 2: Prepare the oil phase solvent.

[0152] Stir 30% benzyl alcohol (alcohol solvent), 10% dimethyl carbonate (ester solvent), 7% ethyl acetate (ester solvent), 5% formic acid (activator), 7.5% OP-10 (surfactant) and 4% hexamethylenetetramine (corrosion inhibitor) at room temperature at a stirring rate of 100-800 rpm until uniformly mixed.

[0153] Step 3: Prepare an oil-water mixed solvent.

[0154] Add the aqueous solution of step 1 to the oil phase of step 2, and stir at room temperature to form an emulsion at a stirring rate of 100-800 rpm.

[0155] Step 4: Preparation of microemulsion.

[0156] Isopropyl alcohol (cosolvent) was slowly added dropwise to the emulsion prepared in step 3 until the emulsion turned from milky white to transparent, thereby forming a microemulsion.

[0157] Comparative Example 1

[0158] Step 1: Prepare the aqueous solvent.

[0159] Add 1.5% NaCl (thickener) and 3% sodium tripolyphosphate (co-surfactant) to 20% deionized water, stir and dissolve at room temperature with a stirring rate of 100~800rpm.

[0160] Step 2: Prepare the oil phase solvent.

[0161] Stir 42% benzyl alcohol (alcohol solvent), 17% dimethyl carbonate (ester solvent), 5% formic acid (activator), 7.5% OP-10 (surfactant) and 4% hexamethylenetetramine (corrosion inhibitor) at room temperature at a stirring rate of 100-800 rpm until uniformly mixed.

[0162] Step 3: Prepare an oil-water mixed solvent.

[0163] Add the aqueous solution of step 1 to the oil phase of step 2, and stir at room temperature to form an emulsion at a stirring rate of 100-800 rpm.

[0164] Removal result verification experiment:

[0165] The components to be stripped are placed in a paint stripper and soaked at room temperature for 1 hour. The components to be stripped include steel and a multi-layer composite paint coated on the outer periphery of the steel, wherein the multi-layer composite paint includes epoxy resin and PVC.

[0166] Figure 2 This is a picture of a paint stripper being used to remove paint from a component to be stripped, corresponding to Example 1 of the present application; Figure 3 The following are pictures of paint stripping components removed by paint strippers corresponding to Examples 1-5 and Comparative Example 1 of the present application. Based on the above stripping results, the following analysis was performed:

[0167] The paint stripper prepared in Example 1 has high permeability and strong cleaning ability, and can quickly break the paint film and separate it from the substrate.

[0168] In the composition of paint strippers, an activator is one of the necessary ingredients, but the choice of solvent as an activator requires screening. The purpose of Example 1, Example 2, and Example 3 is to screen acidic activators and alkaline activators. Among them, Example 2 and Example 3 replace the acidic activator in Example 1 with two different alkaline activators to form alkaline paint strippers. Although Example 2 and Example 3 can quickly break the paint film and separate it from the substrate after soaking for 1 hour, their substrate separation effect is poor compared to Example 1, and only a small part of the substrate is separated. Therefore, for multi-layer composite paints of epoxy resin and PVC paint, the acidic paint stripper is significantly better than the alkaline paint stripper.

[0169] The main reason is that acidic paint strippers react more quickly and can destroy the macromolecular chains in the paint components more quickly, and can achieve better paint stripping effects at room temperature. In many cases, alkaline paint strippers require additional heating or extended soaking time to achieve the corresponding paint stripping effects, but this requires increased energy consumption.

[0170] Therefore, the experimental results based on Example 1, Example 2 and Example 3 show that the acidic paint stripper is significantly better than the alkaline paint stripper, but the alkaline paint stripper can also achieve the paint stripping effect.

[0171] Ester solvents can protect the steel inside the composite paint from severe corrosion during the process of the paint stripper dissolving the composite paint, promote the separation effect of the substrate, and are one of the necessary solvents. Example 4 Compared with Example 1, the ester solvent is replaced by ethyl acetate instead of dimethyl carbonate. After soaking for 1 hour, the paint film can be quickly broken, but the permeability is not enough, and only the paint film and the substrate can be partially separated. Example 5 Compared with Example 1, the ester solvent is replaced by dimethyl carbonate with a mixed solvent of dimethyl carbonate and ethyl acetate instead of dimethyl carbonate. After soaking for 1 hour, the paint film can be quickly broken and most of the substrate can be separated.

[0172] Comparative example 1, embodiment 4 and embodiment 5, the effect of embodiment 1 is better than the effect of embodiment 5, and the effect of embodiment 5 is better than the effect of embodiment 4, therefore, in paint stripper, the adding of dimethyl carbonate is conducive to enhancing its permeability and cleaning ability.Main reason is that dimethyl carbonate is a kind of environment-friendly solvent, is easy to biodegradable.In addition, dimethyl carbonate itself has low viscosity, large surface tension, and contains polar groups such as carbonyl, methoxyl group in its structure, is conducive to its rapid penetration into difficult-to-wash-off coating inside such as PVC paint and multilayer hybrid coating thereof.

[0173] Therefore, based on the results of Examples 4 and 5, it is shown that the addition of dimethyl carbonate to the paint stripper is beneficial to enhancing its permeability and cleaning ability. Ethyl acetate can also achieve rapid rupture of the paint film and substrate separation effect, but the substrate separation effect is not as good as that of dimethyl carbonate.

[0174] Comparative Example 1 is a comparative experiment of Example 1. Compared with the preparation material of Example 1, no cosolvent is added in Comparative Example 1, and a microemulsion cannot be formed. Therefore, Comparative Example 1 is an emulsion paint stripper. Figure 3 As shown, after the paint stripping component is immersed in Comparative Example 1 for 1 hour, the paint film can be broken, but the permeability is insufficient to separate the paint film from the substrate.

[0175] The main reason is that microemulsion has a unique particle size (10-100nm, refer to Figure 4 As shown in Figure 2, it is significantly superior to emulsion paint strippers in terms of both permeability and thermodynamic stability.

[0176] Therefore, based on Example 1 and Comparative Example 1, it can be seen that the cosolvent that promotes the formation of the microemulsion is an essential component solvent in the paint stripper of the present application.

[0177] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. A paint stripper, characterized in that Including the following raw materials: Alcohol solvents, cosolvents, ester solvents, activators, corrosion inhibitors, surfactants, cosurfactants, and deionized water.

2. The paint stripper according to claim 1, characterized in that The raw materials include the following raw materials in weight percentage: 20%-65% alcohol solvent, 5%-20% co-solvent, 5%-30% ester solvent, 1%-10% activator, 1%-5% corrosion inhibitor, 1%-15% surfactant, 1%-5% co-surfactant, and the balance is deionized water.

3. The paint stripper according to claim 1, characterized in that The raw materials also include a thickener.

4. The paint stripper according to claim 3, characterized in that The raw materials include the following raw materials in weight percentage: 20%-45% alcohol solvent, 5%-20% co-solvent, 5%-30% ester solvent, 1%-10% activator, 1%-10% thickener, 1%-5% corrosion inhibitor, 1%-15% surfactant, 1%-5% co-surfactant, and the balance is deionized water.

5. The paint stripper according to any one of claims 1 to 4, characterized in that The alcohol solvent includes one or more of methanol, ethanol, isopropanol, n-butanol, tert-butanol, isobutanol, cyclohexanol, benzyl alcohol, phenylethyl alcohol, diethanol, propylene glycol, glycerol, and pentaerythritol; Preferably, the alcohol solvent includes one or more of benzyl alcohol and phenylethyl alcohol.

6. The paint stripper according to any one of claims 1 to 4, characterized in that The ester solvent includes one or more of ethyl acetate, butyl acetate, ethyl lactate, dimethyl carbonate, ethyl formate, isobutyl formate, isoamyl formate, methyl acetate, n-butyl acetate, amyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, propyl propionate, and n-butyl lactate; Preferably, the ester solvent includes dimethyl carbonate.

7. The paint stripper according to any one of claims 1 to 4, characterized in that The surfactant includes one or more of sodium stearate, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, cetyltrimethylammonium bromide, dodecyldimethylbetaine, N-acylglutamate, AEO-9, OP-10, Span 80, Tween 80, and Tween 20; Preferably, the surfactant includes one or more of OP-10 and Span 80.

8. The paint stripper according to any one of claims 1 to 4, characterized in that The co-surfactant comprises one or more of polyethylene glycol ether, dodecyldimethylamine, n-butanol, triethanolamine oleate, sodium polyacrylate, sodium xylene sulfonate, sodium benzoate, sodium tripolyphosphate, sodium carbonate, sodium sulfate, and borax; Preferably, the co-surfactant includes one or more of polyethylene glycol ether and sodium tripolyphosphate.

9. The paint stripper according to any one of claims 3-4, characterized in that The thickener includes one or more of sodium polyacrylate, polyvinyl alcohol, polyacrylamide, sodium hydroxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, aluminum silicate, sodium chloride, pectin, and agar; Preferably, the thickener includes one or more of sodium hydroxymethyl cellulose, hydroxyethyl cellulose, and sodium chloride.

10. The paint stripper according to any one of claims 1 to 4, characterized in that The corrosion inhibitor includes one or more of sodium silicate, sodium metasilicate pentahydrate, potassium silicate, benzotriazole, tolyltriazole, monoethanolamine, diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, dodecylamine, hexamethylenetetramine, and polyvinyl butyral; Preferably, the corrosion inhibitor includes one or more of dodecylamine and hexamethylenetetramine.

11. The paint stripper according to any one of claims 1 to 4, characterized in that The activator includes an acidic activator and an alkaline activator; preferably, the activator is an acidic activator.

12. The paint stripper according to claim 11, characterized in that The acidic activator includes one or more of phenol, hydrogen peroxide, formic acid, and acetic acid; the alkaline activator includes one or more of ethanolamine, diethanolamine, triethanolamine, sodium hydroxide, and potassium hydroxide; Preferably, the acidic activator includes one or more of formic acid and acetic acid.

13. The paint stripper according to any one of claims 1 to 4, characterized in that The cosolvent includes one or more of methanol, ethanol, propylene glycol, ethylene glycol monomethyl ether, urea, isopropanol, 3-methoxy-3-methyl-1-butanol, dimethyl sulfoxide, ethyl acetate, and acetone; Preferably, the co-solvent includes one or more of ethylene glycol monomethyl ether, isopropyl alcohol, and ethanol.

14. The paint stripper according to any one of claims 1 to 4, characterized in that The paint stripper is a microemulsion; preferably, the particle size of the microemulsion is 10-100 nm.

15. A method for preparing the paint stripper according to any one of claims 1 to 14, characterized in that: The following steps are involved: preparing an aqueous phase solvent and an oil phase solvent; Mixing the aqueous phase solvent and the oil phase solvent, stirring uniformly to obtain an emulsion, and adding a cosolvent to the emulsion to obtain a paint stripper; The aqueous phase solvent includes deionized water dissolved with a co-surfactant; and the oil phase solvent includes a mixed solution of an alcohol solvent, an ester solvent, an activator, a surfactant and a corrosion inhibitor.

16. The preparation method according to claim 15, characterized in that The stirring temperature is lower than 40°C.

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