Environment-friendly online plastic remover and preparation method thereof

Abstract

The invention discloses an environment-friendly online plastic remover which comprises the following components in percentage by weight: 40-89% of an aromatic hydrocarbon compound, 10-40% of an alcohol ether compound, 0.1-5% of a surfactant, 0.5-15% of an alkaline substance and 0-40% of water. The low-toxicity high-boiling-point benzyl alcohol or benzaldehyde is adopted as a main effective component, the rapid plastic removal effect can be achieved, the plastic removal speed is at least four times higher than that of other similar plastic removal agents, and the online plastic removal requirement smaller than 3 min is met. And a small amount of alkaline components need to be added into the plastic removing agent to balance the pH value, so that the deformation of an accompanying hanger is small, the structural strength of a material is not influenced, and the corrosion amount of a base material is small. The plastic removal agent does not contain chloralkane or phenol substances, causes little pollution to the environment, causes little harm to human health, causes little harm to a base material and an operator, and can achieve an environment-friendly plastic removal effect.

Description

Technical Field

[0001] The invention relates to the field of chemical coating or ink remover, and in particular to an environmentally friendly online plastic remover and a preparation method thereof. Background Art

[0002] With the development of industrial automation, electrostatic spraying of powder on the surface of metal products usually relies on accompanying hangers, and online deplasticization of the plastic powder coating on the surface of the accompanying hanger is crucial. Traditional deplasticization methods include strong acid and alkali method, chlorinated alkane deplasticization method, etc. Strong acid and alkali deplasticization is highly corrosive to the accompanying hanger and is dangerous to operate. The chlorinated alkane deplasticization method has certain volatile toxicity and will also cause certain harm to the health of workers. In addition, the strong acid and alkali method and the chlorinated alkane deplasticization method are both offline deplasticization, which is time-consuming and has high labor costs. Therefore, it is very important to develop an online deplasticizer that has a short deplasticization time, low corrosion to the accompanying hanger, does not affect the structural strength of the material, and can be recycled.

[0003] Chinese invention patent CN114672186B discloses a water-based paint stripper and its preparation method, the components include benzyl alcohol, ethylene glycol monobutyl ether, N-methyl pyrrolidone, γ-butyrolactone, dimethyl sulfoxide, phenol, surfactant, polyoxyethylene octylphenol ether-10, ethanolamine, corrosion inhibitor and water, and does not contain strong acid and dichloromethane components, avoiding the problem of concentrated acid pollution in waste liquid and harm to human body, but the plastic removal efficiency is low and it is not suitable for online plastic removal. Chinese invention patent CN113105783A discloses a neutral paint stripper, with phosphate as the main component, but the waste liquid has the hidden danger of causing eutrophication of water bodies. Chinese invention patent CN117924994A discloses a paint stripper free of phenol and halogenated hydrocarbons and a preparation method thereof, the components of which include benzyl alcohol, ethyl acetate, formic acid, methanol, acetic acid, hexadecyltrimethylammonium bromide, emulsifier OP-10 and deionized water. However, the paint stripper has an acidic pH between 2 and 3, is corrosive to the substrate, is volatile, and has poor product stability. Summary of the invention

[0004] In order to develop an online deplasticizer with short deplasticization time, small corrosion to accompanying hangers, no influence on material structural strength, and recyclable use, the first aspect of the present invention provides an environmentally friendly online deplasticizer, which comprises, by weight percentage, 40-89% aromatic hydrocarbon compounds, 10-40% alcohol ether compounds, 0.1-5% surfactants, 0.5-15% alkaline substances, and 0-40% water.

[0005] As a preferred embodiment, the aromatic hydrocarbon compound is selected from at least one of benzyl alcohol, benzaldehyde, benzoic acid and phenylethyl alcohol.

[0006] As a preferred embodiment, the aromatic hydrocarbon compound is selected from at least one of benzyl alcohol and benzaldehyde.

[0007] The inventors found during the experiment that chlorinated alkanes are generally used as the main active ingredients in existing paint stripping and plasticizing agents, which are highly volatile and toxic during use, and are therefore not suitable for online plasticizing, and will cause greater physical harm to workers on site. In this application, low-toxic, high-boiling-point benzyl alcohol or benzaldehyde is used as the main active ingredient to achieve a rapid plasticizing effect and meet the online plasticizing requirement of <3min. The reason may be that benzaldehyde or benzyl alcohol has a similar structure to aliphatic aldehydes or aliphatic alcohols, and can undergo an electrophilic substitution reaction with plastic materials to generate meta-substituents, thereby achieving decomposition and removal of plastic materials. In addition, benzaldehyde or benzyl alcohol has a certain compatibility with the components of plastic materials, which is conducive to dissolving and removing the plastic materials after decomposition, thereby achieving a plasticizing effect.

[0008] As a preferred embodiment, the alcohol ether compound is selected from at least one of ethylene glycol dimethyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether, triethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol dibutyl ether, and ethylene glycol methyl ether.

[0009] As a preferred embodiment, the alcohol ether compound is selected from at least one of ethylene glycol butyl ether, diethylene glycol butyl ether and diethylene glycol methyl ether.

[0010] As a preferred embodiment, the weight ratio of benzaldehyde to ethylene glycol butyl ether is (15-20):(2-5). Preferably, the weight ratio of benzaldehyde to ethylene glycol butyl ether is 16:3.

[0011] As a preferred embodiment, the surfactant is selected from one or a combination of nonionic surfactants and anionic surfactants.

[0012] As a preferred embodiment, the nonionic surfactant is selected from at least one of polyol-type surfactants, alkylphenol polyoxyethylene ether-type surfactants, fatty alcohol polyoxyethylene ethers, and fatty acid polyoxyethylene esters.

[0013] As a preferred embodiment, the polyol-type surfactant is polyethylene glycol, and the polymerization number of the polyethylene glycol is 200-600.

[0014] As a preferred embodiment, the carbon number of the alkyl group in the alkylphenol polyoxyethylene ether type surfactant is 9-14.

[0015] As a preferred embodiment, the nonionic surfactant is selected from at least one of PEG 200, PEG 400, NP-9, OP-10, LF70, and TERGITOL 15-S-5.

[0016] As a preferred embodiment, the nonionic surfactant is selected from at least one of PEG 400, LF70, and OP-10.

[0017] As a preferred embodiment, the alkaline substance includes an inorganic base and an organic base, and the organic base is selected from at least one of sodium methoxide, potassium ethoxide, potassium tert-butoxide, monoethanolamine, diethanolamine, and triethanolamine.

[0018] As a preferred embodiment, the inorganic base is selected from at least one of potassium hydroxide and sodium hydroxide.

[0019] As a preferred embodiment, the alkaline substance is selected from at least one of potassium hydroxide, sodium hydroxide, potassium ethoxide, and monoethanolamine.

[0020] The applicant further discovered that a small amount of alkaline components need to be added to the plasticizer to balance the pH. If the amount of alkaline components added is too large, it will cause corrosion of the plasticizer substrate, especially for amphoteric metals such as zinc plates or aluminum plates. It will also cause metal ions to be free and enter the plasticizer, affecting the recycling of the plasticizer.

[0021] The second aspect of the present invention provides a method for preparing an environmentally friendly online plasticizer, comprising the following steps:

[0022] S1 adds the aromatic hydrocarbon compound into a sealed light-proof container;

[0023] S2 adds the alcohol ether compound to the aromatic hydrocarbon compound and starts stirring;

[0024] S3: Add surfactant during stirring until stirring is uniform;

[0025] S4: adding alkaline substances during stirring until the mixture is stirred and dissolved uniformly;

[0026] Add water to S5 and stir to mix evenly.

[0027] As a preferred embodiment, in step S4, the alkaline substance is pre-dissolved in water or placed in a special dissolving mesh before adding. In step S4, the dissolving temperature is 15-45° C. and the stirring speed is 30-100 r / min.

[0028] As a preferred embodiment, in step S4, the dissolving temperature is 20-40° C. and the stirring speed is 35-50 r / min.

[0029] During the plastic removal process of the plastic removal agent in this application, the liquid level will gradually decrease due to consumption, carryover and volatilization. It is necessary to set the automatic drip flow rate according to the change of the liquid level to ensure that the liquid in the tank remains unchanged and the volatilized working liquid flows back to the plastic removal tank through condensation. Regularly measure the free alkali, keep it within the specified concentration range, and add it slowly in batches, especially when treating substrates such as aluminum and zinc alloys. Free alkali point test method: Use a pipette to transfer 1.0mL of tank liquid to a 250mL conical flask, add 50mL of pure water, add 2-3 drops of phenolphthalein indicator, and then titrate with 0.05mol / L (0.1N) sulfuric acid standard solution. The end point is when the color changes from pink to colorless. The number of milliliters of 0.1N sulfuric acid standard solution consumed multiplied by 10 is the free alkalinity point.

[0030] The deplasticizing tank liquid can be naturally settled, and the plastic powder residue can be settled through a high-level tank, or filtered through a plate filter.

[0031] Before waste liquid treatment, the concentrate should be diluted with wash water at a ratio of at least 1:5 before discharge.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The environmentally friendly online plasticizer of the present invention uses low-toxic and high-boiling-point benzyl alcohol or benzaldehyde as the main effective ingredient, which can achieve a rapid plastic removal effect, which is at least 4 times faster than other similar plasticizers and meets the online plastic removal requirement of <3 min.

[0034] (2) The environmentally friendly online plasticizer of the present invention requires a small amount of alkaline components to be added to the plasticizer to balance the pH, which has a small deformation effect on the accompanying hanger, does not affect the structural strength of the material, and has a small amount of corrosion to the substrate.

[0035] (3) The environmentally friendly online plasticizer of the present invention does not contain chlorinated alkanes or phenols, causes little pollution to the environment, causes little harm to human health, and causes little harm to the substrate and the operator, thereby achieving an environmentally friendly plasticizer effect.

[0036] (4) The environmentally friendly online plasticizer of the present invention does not contain paraffin but contains a hydrophilic surfactant, is easy to wash with water, does not leave an oil film after plastic removal, and does not affect secondary coating.

[0037] (5) The environmentally friendly online deplasticizer of the present invention is non-corrosive to iron substrates and less corrosive to amphoteric metal substrates. The removed plastic powder can be removed by natural sedimentation or filtration, thereby achieving the recycling of the deplasticizer and having a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The corrosion conditions of different rack samples in the plasticizer of Example 1 change with time;

[0039] Figure 2 The corrosion conditions of different rack samples in the plasticizer of Example 2 change with time;

[0040] Figure 3 The corrosion conditions of different rack samples in the plasticizer of Example 3 change with time;

[0041] Figure 4 The corrosion conditions of different rack samples in the plasticizer of Example 4 change with time;

[0042] Figure 5 The corrosion conditions of different rack samples in the release agent of Example 5 change with time;

[0043] Figure 6 The corrosion conditions of different hanger samples in the release agent of Example 6 change with time.

[0044] In the figure: A: iron plate; B: galvanized plate; C: aluminum plate; Ⅰ: before plastic stripping; Ⅱ: 10 minutes after plastic stripping; Ⅲ: 60 minutes after plastic stripping. DETAILED DESCRIPTION

[0045] Example

[0046] An environmentally friendly online plasticizer, the raw materials for its preparation are shown in Table 1 below in terms of weight percentage.

[0047] Table 1

[0048]

[0049] The PEG200, PEG400, NP-9, and OP-10 were purchased from Nanjing Gutian; the LF70 was purchased from Shanghai Jianyong Industrial Co., Ltd.

[0050] A method for preparing an environmentally friendly online plasticizer comprises the following steps:

[0051] S1 adds the aromatic hydrocarbon compound into a sealed light-proof container;

[0052] S2 adds the alcohol ether compound to the aromatic hydrocarbon compound and starts stirring;

[0053] S3: Add surfactant during stirring until stirring is uniform;

[0054] S4: adding alkaline substances during stirring until the mixture is stirred and dissolved uniformly;

[0055] Add water to S5 and stir to mix evenly.

[0056] In step S4, the alkaline substance is preliminarily dissolved in water before being added. If the alkaline substance does not contain water, it is placed in a special dissolving mesh before being added.

[0057] In step S4, the dissolving temperature is 30° C. and the stirring speed is 40 r / min.

[0058] Comparative Example 1

[0059] A plasticizer is prepared from raw materials, measured by weight percentage, including 19.5% benzyl alcohol, 15% ethylene glycol monobutyl ether, 10.5% N-methyl pyrrolidone, 4% gamma-butyrolactone, 4% dimethyl sulfoxide, 10% phenol, 3.5% surfactant JFC-E, 4% surfactant OP-10, 7.5% monoethanolamine, 1.5% thiourea and 20.5% water.

[0060] A method for preparing a plasticizer comprises the following steps: preparing raw materials by uniformly mixing them according to a weight ratio to obtain a plasticizer.

[0061] Comparative Example 2

[0062] A plasticizer is prepared from raw materials, measured by weight percentage, including 35% benzyl alcohol, 7.5% surfactant JFC-E, 7.5% ethylene glycol monoethyl ether, 2% trisodium phosphate, 2% sodium pyrophosphate, 2% sodium tripolyphosphate, 2% sodium metasilicate pentahydrate, 2% sodium gluconate, 4% phosphoric acid and 36% water.

[0063] A method for preparing a plasticizer comprises the following steps: preparing raw materials by uniformly mixing them according to a weight ratio to obtain a plasticizer.

[0064] Comparative Example 3

[0065] A plasticizer is prepared from raw materials including, by weight percentage, 26.5% benzyl alcohol, 18.5% ethyl acetate, 14% methanol, 19% formic acid, 5% acetic acid, 14.5% water, 1.3% hexadecyltrimethylammonium bromide and 1.2% OP-10.

[0066] A method for preparing a plasticizer comprises the following steps: preparing raw materials by uniformly mixing them according to a weight ratio to obtain a plasticizer.

[0067] Performance Testing

[0068] 1. Deplasticization time: for deplasticization of plastic powder with thickness of 120nm and 220nm, the time for completely removing plastic powder from the middle 50mm×100mm position of Q235 cold-rolled steel plate is measured. The shorter the time, the higher the efficiency. Under ultrasonic conditions, the test results of removing 220nm Aksu black powder under different temperature conditions using the deplasticizer of Example 7 and Comparative Examples 1-3 are shown in Table 1; under ultrasonic conditions, the test results of removing 120nm Aksu black powder under different temperature conditions using the deplasticizer of Example 7 and Comparative Examples 1-3 are shown in Table 2.

[0069] Under ultrasonic conditions, the plasticizers of Examples 1-6 were used to remove coatings of different thicknesses. The test results are shown in Table 5.

[0070] 2. Deplasticization efficiency: The plastic powders of 120nm and 220nm thickness were deplasticized by the deplasticizers of Example 7 and Comparative Examples 1-3. The percentage of the area of ​​plastic powder removed from the middle of the sample plate at 50mm×100mm was compared with the area of ​​the middle of the sample plate. The larger the percentage, the higher the efficiency. The test results of removing 220nm Aksu black powder under 50℃ ultrasonic conditions are shown in Table 3; the test results of removing 120nm Aksu black powder under 50℃ ultrasonic conditions are shown in Table 4.

[0071] 3. Corrosion effect: Iron plate, galvanized plate and aluminum plate were immersed in the deplasticizer of Examples 1-6, and the corrosion conditions before deplasticization, 10 minutes after deplasticization and 60 minutes after deplasticization were observed under an electron microscope. The test results are shown in Figure 1-6 In the figure: A: iron plate; B: galvanized plate; C: aluminum plate; Ⅰ: before plastic stripping; Ⅱ: 10 minutes after plastic stripping; Ⅲ: 60 minutes after plastic stripping.

[0072] The iron sample immersed in the plasticizer is basically free of corrosion, and it can be seen from the electron microscope that the surface structure has no obvious change; the surface of the aluminum plate and the galvanized plate immersed for a long time is slightly discolored and darkened. It can be seen from the electron microscope that the surface structure of the galvanized and aluminum of Examples 1, 3, and 6 has a slight corrosion phenomenon. The reason is that the plasticizer is an alkaline plasticizing product, but the alkali content is low, and there will be a small amount of chemical corrosion for the amphoteric metals of zinc and aluminum. For Examples 2, 4, and 5, the surface corrosion is more serious under the process conditions, which is not suitable for the plasticizing process of precision instruments. As for the ICP data analysis from the supernatant of the plasticizer, it is found that a small amount of aluminum and zinc elements enter the plasticizer, while the iron element is basically not increased.

[0073] Table 1

[0074] 50℃ 60℃ 70℃ Comparative Example 1 110 30 25 Comparative Example 2 45 24 20 Comparative Example 3 38 16 13 Example 7 4 3 2.5

[0075] Table 2

[0076]

[0077]

[0078] Table 3

[0079] time 10min 20min 30min 40min 50min 70min 90min 110min Comparative Example 1 0％ 0％ 2％ 5％ 10％ 30％ 80％ 100％ Comparative Example 2 1％ 5％ 15％ 60％ 100％ Comparative Example 3 2％ 5％ 70％ 100％ Example 7 100％

[0080] Table 4

[0081] time 10min 20min 30min 40min Comparative Example 1 5％ 10％ 90％ 100％ Comparative Example 2 40％ 80％ 100％ Comparative Example 3 80％ 100％ Example 7 100％

[0082] Table 5

[0083]

[0084]

Claims

1. An environmentally friendly online plasticizer, characterized in that: Calculated by weight percentage, it comprises 40-89% aromatic hydrocarbon compound, 10-40% alcohol ether compound, 0.1-5% surfactant, 0.5-15% alkaline substance and 0-40% water.

2. The environmentally friendly online plasticizer according to claim 1, characterized in that: The aromatic hydrocarbon compound is selected from at least one of benzyl alcohol, benzaldehyde, benzoic acid and phenylethyl alcohol.

3. The environmentally friendly online plasticizer according to claim 1, characterized in that: The alcohol ether compound is selected from at least one of ethylene glycol dimethyl ether, ethylene glycol butyl ether, diethylene glycol butyl ether, triethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol dibutyl ether and ethylene glycol methyl ether.

4. The environmentally friendly online plasticizer according to claim 1, characterized in that: The surfactant is selected from nonionic surfactants, anionic surfactants or a combination of both.

5. The environmentally friendly online plasticizer according to claim 4, characterized in that: The nonionic surfactant is selected from at least one of polyol surfactants, alkylphenol polyoxyethylene ether surfactants, fatty alcohol polyoxyethylene ethers, and fatty acid polyoxyethylene esters.

6. The environmentally friendly online plasticizer according to claim 5, characterized in that: The polyol surfactant is polyethylene glycol, and the polymerization number of the polyethylene glycol is 200-600.

7. The environmentally friendly online plasticizer according to claim 5, characterized in that: The carbon number of the alkyl group in the alkylphenol polyoxyethylene ether type surfactant is 9-14.

8. The environmentally friendly online plasticizer according to claim 1, characterized in that: The alkaline substance includes an inorganic base and an organic base, and the organic base is selected from at least one of sodium methoxide, potassium ethoxide, potassium tert-butoxide, monoethanolamine, diethanolamine, and triethanolamine.

9. A method for preparing the environmentally friendly online plasticizer according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1 adds the aromatic hydrocarbon compound into a sealed light-proof container; S2 adds the alcohol ether compound to the aromatic hydrocarbon compound and starts stirring; S3: Add surfactant during stirring until stirring is uniform; S4: adding alkaline substances during stirring until the mixture is stirred and dissolved uniformly; Add water to S5 and stir to mix evenly.

10. The method for preparing the environmentally friendly online plasticizer according to claim 9, characterized in that: In step S4, the alkaline substance is pre-dissolved with water or placed in a special dissolving mesh before adding. In step S4, the dissolving temperature is 15-45° C. and the stirring speed is 30-100 r / min.

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