Phosphorus-free and nitrogen-free environment-friendly low-temperature oil removing agent and preparation method thereof

Abstract

This invention relates to a phosphorus- and nitrogen-free environmentally friendly low-temperature degreasing agent and its preparation method, belonging to the technical field of industrial cleaning agents. The degreasing agent comprises isomeric tridecyl alcohol polyoxyethylene ether, modified alkyl glycoside, polyepoxysuccinic acid, sodium citrate, modified hydrotalcite, zinc borate, potassium hydroxide, potassium carbonate, and diethylene glycol butyl ether. The modified alkyl glycoside is prepared by reacting epoxysuccinic acid and polyethylene glycol diglycidyl ether sequentially with the alkyl glycoside. This invention constructs a nitrogen-free inorganic pH buffer system through the compounding of potassium carbonate and modified hydrotalcite, forming an aluminum protection mechanism through pH control, alkyl glycoside hydrogen bond adsorption, zinc borate physical barrier, and aluminum citrate ion chelation. The degreasing agent of this invention does not contain phosphorus or nitrogen.

Description

Technical Field

[0001] This invention belongs to the field of industrial cleaning agent technology, and relates to a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent and its preparation method. Background Technology

[0002] Industrial degreasing and cleaning agents are widely used in machining, electronics manufacturing, automotive, aerospace, and other fields. Traditional industrial cleaning agents mostly rely on phosphates as detergent builders and nitrogen-containing surfactants (such as alkanolamines and amides) as emulsifiers and pH adjusters. Although these cleaning agents have good detergency, phosphorus emissions can lead to eutrophication of water bodies and cause environmental problems such as red tides; nitrogen-containing compounds increase the burden on water treatment and may form carcinogenic byproducts such as nitrosamines. With increasingly stringent environmental regulations, the development of phosphorus-free and nitrogen-free environmentally friendly cleaning agents has become an urgent need for industry development.

[0003] To address these issues, researchers have developed various phosphorus-free degreasing technologies. For example, Chinese patent CN114892178A discloses a silicon-free, phosphorus-free, environmentally friendly water-based degreasing agent that uses polyepoxysuccinic acid (PESA) and hydrolyzed polymaleic anhydride (HPMA) as dispersants, combined with various surfactants, to achieve phosphorus-free degreasing. However, this technology still has the following shortcomings: First, its pH buffering depends on nitrogen-containing organic bases (such as Hostacor 692), failing to achieve the nitrogen-free target; second, its surfactant system uses traditional nonionic surfactants such as nonylphenol polyoxyethylene ether (NP-10), which have poor biodegradability and limited corrosion inhibition effect on metals.

[0004] Chinese patent CN102041517A discloses a water-soluble, phosphorus-free degreasing agent for permanent magnet materials. It uses polyacrylic acid polymer as a cleaning aid to achieve phosphorus-free treatment. However, the cleaning aid contains acrylamide copolymer, which introduces nitrogen elements and fails to achieve the nitrogen-free target.

[0005] Chinese patent CN108179425A discloses an environmentally friendly degreasing agent that uses surfactants such as sodium isomeric alcohol polyoxyethylene ether sulfate. However, the formula contains nitrogen-containing surfactants such as coconut oil diethanolamide, and the system is acidic, making it unsuitable for alkaline degreasing of aluminum materials.

[0006] Therefore, there is an urgent need to develop a truly phosphorus-free, nitrogen-free, low-temperature, and highly efficient environmentally friendly degreasing agent to meet increasingly stringent environmental protection requirements. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent and its preparation method, thereby improving the technical problems of existing degreasing agents containing phosphorus and nitrogen, low low-temperature degreasing efficiency, high operating temperature and high energy consumption, easy corrosion of aluminum materials, and the presence of environmentally unfriendly substances such as APEO in the surfactant system.

[0008] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent, comprising the following components in parts by weight: 6-8 parts of isomeric tridecyl alcohol polyoxyethylene ether; 3-5 parts of modified alkyl glycoside; 1-2 parts of polyepoxysuccinic acid; 1-2 parts sodium citrate; 0.5-1 part of modified hydrotalcite; 0.5-1 part zinc borate; Potassium hydroxide 0.3-0.8 parts; Potassium carbonate 1.5-3 parts; 2-4 parts of diethylene glycol butyl ether; The modified alkyl glycoside is obtained by sequentially modifying the alkyl glycoside with epoxy succinic acid and polyethylene glycol diglycidyl ether.

[0009] As used in this text, the term "phosphorus-free and nitrogen-free" means that no phosphorus compounds (such as phosphates and phosphonates) or nitrogen compounds (such as alkanolamines, amides, and quaternary ammonium salts) are added as functional additives to the degreasing agent.

[0010] Polyepoxysuccinic acid is a phosphorus-free and nitrogen-free biodegradable polymer that can chelate calcium and magnesium ions and disperse oil particles.

[0011] Alkyl glycosides are nonionic surfactants formed by the condensation of glucose and fatty alcohols, possessing excellent biodegradability, low irritation, and no cloud point. Modified alkyl glycosides refer to alkyl glycosides that have been chemically modified to introduce functional groups or segments, thereby enhancing their emulsifying, dispersing, or chelating properties.

[0012] Preferably, the modified alkyl glycoside is prepared by: A. Epoxysuccinic acid reacts with alkyl glycosides in the presence of a basic catalyst to obtain epoxysuccinic acid-modified alkyl glycosides. B. Add polyethylene glycol diglycidyl ether and continue the reaction to obtain modified alkyl glycosides.

[0013] Preferably, in step A, the mass ratio of alkyl glycoside to epoxy succinic acid is 1:0.2-0.3, the reaction temperature is 80-95℃, and the reaction time is 2-3 hours.

[0014] Preferably, in step B, the mass ratio of alkyl glycoside to polyethylene glycol diglycidyl ether is 1:0.05-0.08, the reaction temperature is 70-90℃, and the reaction time is 1-2 hours.

[0015] The preparation of modified alkyl glycosides can be carried out in steps in the same reactor. That is, the reaction between epoxy succinic acid and alkyl glycoside is carried out first, and after the reaction is completed, polyethylene glycol diglycidyl ether is added to continue the reaction without the need to separate intermediate products.

[0016] Preferably, the alkyl carbon chain length of the alkyl glycoside is C8-C14. More preferably, the alkyl glycoside may be APG0810, APG1214, or a mixture thereof, wherein APG0810 has better water solubility, APG1214 has stronger emulsifying ability, and the combination of the two can obtain better overall performance.

[0017] Modified hydrotalcite refers to hydrotalcite incorporating organic anions (citrate or tartrate) into its interlayer via ion exchange, thereby imparting pH buffering and corrosion inhibition properties. Preferably, the modified hydrotalcite is prepared by dispersing magnesium aluminum hydrotalcite in water, adding sodium citrate or potassium sodium tartrate, stirring at 60-80°C for 2-3 hours, filtering, washing, drying, and then vacuum dehydrating at 105-110°C for 2-3 hours to obtain the modified hydrotalcite. As another preferred embodiment of the invention, the modified hydrotalcite can use a mixture of sodium citrate and potassium sodium tartrate as a modifier, simultaneously introducing two organic anions.

[0018] The degreasing mechanism of this invention is based on the synergistic effect of multiple components: First, isomeric tridecyl alcohol polyoxyethylene ether and modified alkyl glycosides serve as primary and secondary surfactants, achieving decontamination by reducing the interfacial tension between oil and water and emulsifying oil stains. This invention utilizes the chemical modification of alkyl glycosides (dual modification with epoxy succinic acid and polyethylene glycol diglycidyl ether) and their combination with isomeric tridecyl alcohol polyoxyethylene ether to simultaneously possess emulsification, chelation, and steric hindrance dispersion functions, thereby achieving rapid emulsification and stable dispersion of oil stains.

[0019] Secondly, pH buffering mechanism: This invention abandons nitrogen-containing organic bases and uses modified hydrotalcite and potassium carbonate to form a nitrogen-free pH buffering system to maintain the pH stability of the cleaning solution.

[0020] In addition, polyepoxysuccinic acid and sodium citrate prevent soap scum formation and redeposition by chelating calcium, magnesium and aluminum ions in water; diethylene glycol butyl ether acts as a solvent to help dissolve oil stains and solubilize surfactants.

[0021] This invention provides multi-dimensional protection for aluminum materials: pH control: Keep the working pH within the safe window of 10-11 to reduce corrosion driving forces from the source.

[0022] Hydrogen bond adsorption film formation: The hydroxyl groups of the modified alkyl glycosides are firmly adsorbed onto the aluminum surface through hydrogen bonds, forming a dense protective layer that blocks OH groups. - erosion.

[0023] Physical barrier and ion chelation: Zinc borate, as nano-sized insoluble particles, is physically deposited on the micro-defects of the aluminum surface, forming an inert barrier layer to inhibit pitting corrosion. Sodium citrate rapidly chelates any trace amounts of Al that may be generated. 3+ This prevents corrosion products from forming insoluble dirt on the surface.

[0024] Secondly, the present invention provides a method for preparing a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent, comprising the following steps: (1) Add water to the reaction system, heat to 40-50℃, add polyepoxysuccinic acid and sodium citrate, and stir to dissolve; (2) Cool down to 30-35℃, add isomeric tridecyl alcohol polyoxyethylene ether and modified alkyl glycoside in sequence, and stir until a transparent and homogeneous liquid is formed; (3) Add diethylene glycol butyl ether, zinc borate and modified hydrotalcite, and stir until homogeneous; (4) Add potassium hydroxide and potassium carbonate to adjust the pH of the system to 10-11; (5) Let stand for 1-2 hours, then discharge the material to obtain the phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent.

[0025] Preferably, the stirring time in step (1) is 10-20 minutes to ensure that the polyepoxysuccinic acid and sodium citrate are completely dissolved.

[0026] Preferably, the stirring speed in step (2) is 50-100 rpm.

[0027] Thirdly, this invention provides an application of a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent in aluminum material processing.

[0028] Aluminum is highly susceptible to corrosion in alkaline systems. This invention protects aluminum through the following design: First, the pH is controlled at 10-11 to prevent severe corrosion from strong alkalis; second, the hydroxyl groups of alkyl glycosides form a hydrogen-bonded adsorption film on the aluminum surface; third, zinc borate physically adsorbs onto the aluminum surface, forming an inert protective film that effectively isolates the aluminum substrate from alkaline cleaning solutions, enhancing protection; finally, sodium citrate chelates the Al produced during aluminum dissolution. 3+ This prevents the formation of insoluble precipitates on the surface.

[0029] The beneficial effects of this invention are as follows: (1) This invention performs dual chemical modification on alkyl glycosides to enhance their functionality. Step 1 (Epoxysuccinic acid modification): While retaining the excellent emulsifying properties of alkyl glycosides, a carboxylic acid group is introduced to enable them to chelate Al... 3+ The first step (crosslinking of polyethylene glycol diglycidyl ether) prevents the formation of aluminum scale. The second step (crosslinking of polyethylene glycol diglycidyl ether) forms a spatial network structure through appropriate crosslinking, generating a strong steric hindrance effect, effectively preventing the re-agglomeration of emulsified oil droplets and improving the anti-redeposition ability of the cleaning solution. When used in combination with isomeric tridecyl alcohol polyoxyethylene ether, it works synergistically to achieve the same degreasing effect.

[0030] (2) Modified hydrotalcite and potassium carbonate were used as a nitrogen-free pH buffer system to replace nitrogen-containing organic bases. Potassium carbonate provided an initial alkaline environment (pH 10-11) to ensure the saponification reaction proceeded. Modified hydrotalcite utilized its interlayer anion exchange properties to adjust the OH groups during the cleaning process. - The concentration, in synergy with potassium carbonate, achieves macroscopic stability and microscopic buffering, preventing drastic pH fluctuations.

[0031] (3) Adsorption via hydrogen bonding of alkyl glycosides, physical barrier of zinc borate, and Al of sodium citrate 3+ The chelation process forms a triple protection mechanism for aluminum, inhibiting corrosion. This product can effectively remove oil at low temperatures of 20-30℃ and contains no phosphorus or nitrogen. Detailed Implementation

[0032] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0033] Example 1 A method for preparing a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent includes the following steps: raw material: 7 parts of isomeric tridecyl alcohol polyoxyethylene ether; 4 parts of modified alkyl glycoside; 1.5 parts of polyepoxysuccinic acid; Sodium citrate 1.5 parts; 0.8 parts of sodium citrate-modified hydrotalcite; 0.8 parts zinc borate; 0.5 parts potassium hydroxide; 2 parts potassium carbonate; 3 parts of diethylene glycol butyl ether; Preparation steps: (1) Add water to the reactor, heat to 45°C, add polyepoxysuccinic acid and sodium citrate, and stir for 15 minutes until completely dissolved; (2) Cool down to 32°C, add isomeric tridecyl alcohol polyoxyethylene ether and modified alkyl glycoside in sequence, and stir slowly (80 rpm) until a transparent and homogeneous liquid is formed; (3) Add diethylene glycol butyl ether, zinc borate and sodium citrate modified hydrotalcite, and stir until homogeneous; (4) Add potassium hydroxide and potassium carbonate to adjust the pH of the system to 10.5; (5) Let it stand for 1.5 hours and then discharge it to obtain a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent.

[0034] Preparation of modified alkyl glycosides: 100g of alkyl glycoside (APG0814) and 200g of water were added to the reaction mixture and stirred until homogeneous. Potassium hydroxide was added to adjust the pH to 10, and the temperature was raised to 90℃. 25g of epoxysuccinic acid was slowly added, and after the addition was complete, the reaction was maintained at 90℃ for 2.5 hours.

[0035] The temperature was lowered to 80℃, and 6g of polyethylene glycol diglycidyl ether (PEGDGE) was slowly added. After the addition was complete, the mixture was kept at this temperature for 1.5 hours. After the reaction was completed, the mixture was cooled and discharged to obtain the modified alkyl glycoside.

[0036] Preparation of modified hydrotalcite: 100g of magnesium aluminum hydrotalcite was dispersed in 500g of water and stirred to form a uniform slurry. 20g of sodium citrate was added as a modifier, the temperature was raised to 70℃, and the mixture was stirred for 2.5 hours. After the reaction was completed, the mixture was filtered, the filter cake was washed three times with water, and then dehydrated under vacuum at 105-110℃ for 2.5 hours. The cake was then pulverized and sieved to obtain sodium citrate-modified hydrotalcite.

[0037] Example 2 A method for preparing a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent includes the following steps: raw material: 8 parts of isomeric tridecyl alcohol polyoxyethylene ether; 5 parts of modified alkyl glycoside; 2 parts of polyepoxysuccinic acid; 2 parts sodium citrate; 1 part of sodium citrate-modified hydrotalcite; 1 part zinc borate; 0.8 parts potassium hydroxide; 3 parts potassium carbonate; 4 parts of diethylene glycol butyl ether; Preparation steps: (1) Add water to the reactor, heat to 45°C, add polyepoxysuccinic acid and sodium citrate, and stir for 20 minutes until completely dissolved; (2) Cool down to 35°C, add isomeric tridecyl alcohol polyoxyethylene ether and modified alkyl glycoside in sequence, and stir slowly (100 rpm) until a transparent and homogeneous liquid is formed; (3) Add diethylene glycol butyl ether, zinc borate and sodium citrate modified hydrotalcite, and stir until homogeneous; (4) Add potassium hydroxide and potassium carbonate to adjust the pH of the system to 11.0; (5) Let stand for 2 hours to age, then discharge the material to obtain a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent.

[0038] Example 3 A method for preparing a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent includes the following steps: raw material: 6 parts of isomeric tridecyl alcohol polyoxyethylene ether; 3 parts of modified alkyl glycoside; 1 part of polyepoxysuccinic acid; 1 part sodium citrate; 0.5 parts of potassium sodium tartrate modified hydrotalcite; 0.5 parts zinc borate; 0.3 parts potassium hydroxide; 1.5 parts potassium carbonate; 2 parts of diethylene glycol butyl ether; Preparation steps: (1) Add water to the reactor, heat to 45°C, add polyepoxysuccinic acid and sodium citrate, and stir for 10 minutes until completely dissolved; (2) Cool down to 30°C, add isomeric tridecyl alcohol polyoxyethylene ether and modified alkyl glycoside in sequence, and stir slowly (80 rpm) until a transparent and homogeneous liquid is formed; (3) Add diethylene glycol butyl ether, zinc borate and modified hydrotalcite, and stir until homogeneous; (4) Add potassium hydroxide and potassium carbonate to adjust the pH of the system to 10.0; (5) Let it stand for 1.5 hours and then discharge it to obtain a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent.

[0039] Comparative Example 1 The results are basically the same as in Example 1, except that the modified alkyl glycoside is replaced with an equal amount of unmodified alkyl glycoside (APG0814), while the other components remain unchanged.

[0040] Comparative Example 2 The method is basically the same as in Example 1, except that: no modified hydrotalcite is added, the amount of potassium hydroxide is adjusted to 0.6 parts, the amount of potassium carbonate is adjusted to 2.2 parts, and the other components remain unchanged.

[0041] Performance testing: (1) Oil removal rate test Aluminum alloy test pieces (50mm×50mm×1mm) were cleaned with acetone, dried, and weighed (W0). The test pieces were then immersed in artificial oil (N46# hydraulic oil: Vaseline = 7:3), drained, dried at 120℃ for 2 hours, cooled, and weighed (W1). Oil-soaked test pieces were immersed in a 5% degreasing agent working solution at 25℃ for 5 minutes, rinsed with water, dried at 120℃, and weighed (W2). The degreasing rate was calculated using the following formula: Degreasing rate (%) = (W1 - W2) / (W1 - W0) × 100%; (2) Corrosion weight loss test of aluminum material Clean, dry, and weigh the aluminum alloy test piece (M0). Immerse the test piece in a 5% degreasing agent working solution at 25℃ for 5 minutes, remove, rinse with water, dry, and weigh (M1). Corrosion weight loss is calculated using the following formula: Corrosion weight loss (mg) = M0 - M1; (3) Foam performance test Following the method in GB / T 7462-94, the degreasing agent was prepared into a 2 g / L working solution, and the foam was tested after 5 minutes using a Ross-Miles foam meter.

[0042] Test Results

[0043] The degreasing rates of Examples 1-3 at 25°C reached 98.5%, 99.1%, and 97.5%, respectively, all higher than those of Comparative Examples 1 and 2, indicating that the modified alkyl glycoside of the present invention is beneficial for improving the low-temperature degreasing efficiency. The aluminum corrosion weight loss of Examples 1-3 was 1.2 mg, 1.1 mg, and 1.4 mg, respectively, which was similar to that of Comparative Example 1 (1.5 mg), indicating that the degreasing agent of the present invention has a good protective effect on aluminum materials. In addition, the degreasing agent provided by the present invention is free of phosphorus and nitrogen, which meets the environmental protection requirements.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent, characterized in that, It contains the following components in parts by weight: 6-8 parts of isomeric tridecyl alcohol polyoxyethylene ether; 3-5 parts of modified alkyl glycoside; 1-2 parts of polyepoxysuccinic acid; 1-2 parts sodium citrate; 0.5-1 part of modified hydrotalcite; 0.5-1 part zinc borate; Potassium hydroxide 0.3-0.8 parts; Potassium carbonate 1.5-3 parts; 2-4 parts of diethylene glycol butyl ether; The modified alkyl glycoside is obtained by sequentially modifying the alkyl glycoside with epoxy succinic acid and polyethylene glycol diglycidyl ether.

2. The phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent according to claim 1, characterized in that, The modified hydrotalcite is sodium citrate modified hydrotalcite or potassium sodium tartrate modified hydrotalcite.

3. The phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent according to claim 1, characterized in that, The modified hydrotalcite was prepared by dispersing magnesium aluminum hydrotalcite in water, adding sodium citrate or potassium sodium tartrate, stirring at 60-80℃ for 2-3 hours, filtering, washing, drying, and then vacuum dehydrating at 105-110℃ for 2-3 hours to obtain the modified hydrotalcite.

4. The phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent according to claim 1, characterized in that, The alkyl glycoside has an alkyl carbon chain length of C8-C14.

5. The phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent according to claim 1, characterized in that, The modified alkyl glycoside is prepared by the following method: A. Epoxysuccinic acid reacts with alkyl glycosides in the presence of a basic catalyst to obtain epoxysuccinic acid-modified alkyl glycosides. B. Add polyethylene glycol diglycidyl ether and continue the reaction to obtain modified alkyl glycosides.

6. The phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent according to claim 5, characterized in that, In step A, the mass ratio of alkyl glycoside to epoxy succinic acid is 1:0.2-0.3, the reaction temperature is 80-95℃, and the reaction time is 2-3 hours.

7. The phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent according to claim 5, characterized in that, In step B, the mass ratio of alkyl glycoside to polyethylene glycol diglycidyl ether is 1:0.05-0.08, the reaction temperature is 70-90℃, and the reaction time is 1-2 hours.

8. A method for preparing a phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent as described in any one of claims 1-7, characterized in that, Includes the following steps: (1) Add water to the reaction system, heat to 40-50℃, add polyepoxysuccinic acid and sodium citrate, and stir to dissolve; (2) Cool down to 30-35℃, add isomeric tridecyl alcohol polyoxyethylene ether and modified alkyl glycoside in sequence, and stir until a transparent and homogeneous liquid is formed; (3) Add diethylene glycol butyl ether, zinc borate and modified hydrotalcite, and stir until homogeneous; (4) Add potassium hydroxide and potassium carbonate to adjust the pH of the system to 10-11; (5) Let stand for 1-2 hours, then discharge the material to obtain the phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent.

9. The preparation method according to claim 8, characterized in that, The stirring speed in step (2) is 50-100 rpm.

10. The application of the phosphorus-free and nitrogen-free environmentally friendly low-temperature degreasing agent according to any one of claims 1-7 in aluminum material treatment.

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