A special cleaning solution for aluminum alloy parts processing process instead of hydrocarbon cleaning solution

Abstract

The present application relates to a kind of special cleaning solution for oil stain cleaning in the processing of aluminum alloy parts, which replaces hydrocarbon cleaning solution.The method of the present application is as follows: long-chain alkyl glycoside (APG) and oleic acid polyethylene glycol ester (PEG) with good biodegradability are used as detergent, low molecular weight acrylic acid-acrylamide copolymer is compounded with phytic acid as corrosion inhibitor, triethanolamine, sodium tripolyphosphate, hydroxyethylidene diphosphonic acid (HTPE) and other washing aids are used as washing aids, and antioxidants, defoamers and other aids are added, to produce aluminum alloy parts special cleaning solution by composite process.The cleaning solution has good washing performance, very low corrosivity, good biodegradability and other advantages, and can completely replace the currently used hydrocarbon cleaning solution in production.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation of a special cleaning solution for replacing carbon hydrogen cleaning solution for aluminum alloy parts processing, belonging to the technical field of metal cleaning solution. BACKGROUND

[0002] In the process of machining aluminum alloy parts, oil-based metal processing aids and metal surface protection aids and other oil stains need to be completely removed before further processing of the parts. Therefore, cleaning agent is a kind of processing aid that must be used in the process of machining aluminum alloy parts.

[0003] The most commonly used cleaning solution in the aluminum alloy parts industry is oil-based cleaning solution, such as gasoline, kerosene or other organic solvents, which are also known as carbon hydrogen cleaning solution. The advantages of carbon hydrogen cleaning solution are high cleaning efficiency, low corrosion to aluminum alloy, and can meet the needs of most aluminum alloy parts processing. However, the biggest problem is that carbon hydrogen cleaning solution has high volatility, and a large amount of organic matter is released into the environment during use, causing serious environmental pollution. In addition, carbon hydrogen cleaning solution is flammable and explosive, which poses a serious safety risk during use, and is also relatively expensive, resulting in high use cost due to high volatilization loss. Therefore, replacing carbon hydrogen cleaning solution with environmentally friendly water-based cleaning solution has become an important issue in the technical progress of the field.

[0004] Since aluminum is a chemically active metal, it has poor corrosion resistance in aqueous solution, so the most important problem in the study of water-based cleaning solution is the corrosion resistance of aluminum alloy. Early research work found that silicates, chromates, sodium carbonate, sodium molybdate, phosphates, citric acid, benzotriazole, sodium dodecyl sulfate and phytate have certain corrosion inhibition effect on aluminum alloy. Currently, the water-based cleaning solution for aluminum alloy used in industry generally uses one or more of the above aluminum alloy corrosion inhibitors as corrosion inhibitors, but the corrosion inhibition effect is generally not good, especially under neutral conditions, the corrosion inhibition effect is even worse, which is difficult to meet the needs of aluminum alloy parts processing.

[0005] In addition, in order to ensure the washing effect of water-based cleaning solution, a large amount of anionic or nonionic surfactant needs to be used in the cleaning solution, and these surfactants generally have poor biodegradability, increasing the treatment cost of washing wastewater and causing a certain degree of environmental pollution problem. Therefore, improving the biodegradability of washing wastewater is also one of the technical requirements in the field.

[0006] The purpose of the present application is to solve the above problems from two aspects of improving the corrosion inhibitor release performance and selecting surfactants with good biodegradability, and to develop a new type of aluminum alloy water-based cleaning solution with excellent corrosion inhibition effect and good biodegradability. SUMMARY

[0007] The technical principle of the present application is as follows: the mechanism of corrosion inhibition of aluminum alloy is mainly to form a dense inert protective layer on the surface of aluminum alloy to prevent the cleaning solution from eroding the surface of aluminum alloy. The protective layer formed by the commonly used corrosion inhibitor of aluminum alloy is not stable or not dense enough to prevent corrosion under harsh conditions (such as low PH value, high washing temperature, etc.). The present application uses a propylene acid-acrylamide low molecular copolymer compounded with phytic acid. The compound can form a hard and dense chelate with aluminum ions on the surface of aluminum alloy. This chelate forms a uniform protective film on the surface of aluminum alloy to achieve the purpose of protecting aluminum alloy from further erosion. The propylene acid-acrylamide / phytic acid / aluminum ion chelate is stable under weakly acidic to weakly basic conditions, so it can play a protective role on aluminum alloy under various PH conditions.

[0008] The low molecular weight propylene acid-acrylamide copolymer used in the present application is prepared by the following method: the molar ratio of acrylic acid to acrylamide is 2-5:1, azobisisobutyronitrile is used as initiator, the amount of initiator is adjusted to make the polymerization degree of propylene acid-acrylamide oligomer 5-15, pure water is used as polymerization solvent, and the temperature is 70-80℃ to obtain propylene acid-acrylamide oligomer.

[0009] The oil stain in the aluminum alloy processing process is generally mineral oil, and a surfactant with suitable HLB value is needed as a cleaning agent. The present application selects a compound of alkyl glycoside APG1214 and oleic acid polyethylene glycol ester PEG200 with good biodegradability as the active component of the cleaning solution. The ratio of APG1214 to PEG200 is 2:1, and the amount of the compound active component in the cleaning solution is 8-15%.

[0010] In the cleaning process of aluminum alloy parts, in order to reduce the influence of water quality on the cleaning effect, prevent the deposition of solid pollutants in the cleaning solution on the surface of the parts, reduce the corrosion inhibition effect, and add appropriate cleaning aids. The present application selects a compound of triethanolamine, sodium tripolyphosphate and hydroxyethylidene diphosphonic acid (HEDP) with good complexation and dispersion performance for metal ions as a cleaning agent to increase the cleaning effect. The specific composition is triethanolamine 20%, sodium tripolyphosphate 45%, and HEDP 35%. The amount of the compound cleaning aid added in the cleaning solution is 10-25%.

[0011] In addition to the above main components, an appropriate amount of antioxidant (tert-butyl hydroquinone) and defoaming agent (organic silicon) is added in the cleaning solution to improve the storage stability of the cleaning solution and reduce the foam in the cleaning process.

[0012] The advantages of the present application are as follows:

[0013] 1. The cleaning solution of the present application has high washing efficiency. 5% concentration of the cleaning solution can complete the cleaning of aluminum alloy parts with heavy pollution, and the cleaning degree reaches more than 99%.

[0014] 2. The cleaning solution of the present application has good corrosion inhibition effect on aluminum alloy. 5-20% concentration of the cleaning solution is soaked at 80°C for 4 hours, and the surface of the aluminum alloy (aluminum alloy 3A21, 4A01, 5052,

[0015] 6061, 7075, etc. from three to seven systems) has no visible change.

[0016] 3. The cleaning solution of the present application has good biodegradability. The BOD5 / COD cr value of the washing wastewater (1% concentration of the cleaning solution) is 0.85. Specific embodiments

[0017] The following examples are intended to further illustrate the specific content of the present application, but the scope and method of implementation of the present application are not limited to the description given below.

[0018] Example 1

[0019] Preparation of low molecular weight acrylic acid-acrylamide copolymer: 29g of distilled acrylic acid, 7g of acrylamide (molar ratio 4:1) were placed in a 200ml reaction bottle, 4.1g of analytical pure azobisisobutyronitrile was added, 40ml of pure water was added, heated to 80°C, and reacted for 6 hours. Acrylic acid-acrylamide copolymer with a degree of polymerization of 10 was obtained, named PAAM-4-10.

[0020] Example 2

[0021] The operation is the same as in Example 1, except that the amount of azobisisobutyronitrile added is changed to 8.2g, and acrylic acid-acrylamide copolymer with a degree of polymerization of 5 is obtained, named PAAM-4-5.

[0022] Example 3

[0023] The operation is the same as in Example 1, except that the amount of azobisisobutyronitrile added is changed to 2.5g, and acrylic acid-acrylamide copolymer with a degree of polymerization of 15 is obtained, named PAAM-4-15.

[0024] Example 4

[0025] 14g of distilled acrylic acid, 7g of acrylamide (molar ratio 2:1) were placed in a 200ml reaction bottle, 2.5g of analytical pure azobisisobutyronitrile was added, 25ml of pure water was added, heated to 80°C, and reacted for 6 hours. Acrylic acid-acrylamide copolymer with a degree of polymerization of 10 was obtained, named PAAM-2-10.

[0026] Example 5

[0027] Distilled acrylic acid 21.5 g, acrylamide 7 g (molar ratio 3:1) were placed in a 200 ml reaction bottle, analytical pure azobisisobutyronitrile 3.3 g was added, pure water 30 ml was added, heated to 80 °C, and incubated for 6 hours to obtain an acrylic acid-acrylamide copolymer with a degree of polymerization of 10, named PAAM-3-10.

[0028] Example 6

[0029] Distilled acrylic acid 36 g, acrylamide 7 g (molar ratio 2:1) were placed in a 200 ml reaction bottle, analytical pure azobisisobutyronitrile 5 g was added, pure water 50 ml was added, heated to 80 °C, and incubated for 6 hours to obtain an acrylic acid-acrylamide copolymer with a degree of polymerization of 10, named PAAM-5-10.

[0030] Example 7

[0031] The composite corrosion inhibitor was prepared as follows: PAAM-4-10 (50% aqueous solution) 40 g prepared above, analytical pure phytic acid 10 g was added, heated to 50 °C and stirred for 1 hour to obtain a composite corrosion inhibitor, named ACI-1.

[0032] Example 8

[0033] The operation of Example 7 was the same, except that the amount of PAAM-4-10 (50% aqueous solution) was changed to 20 g, and the obtained composite corrosion inhibitor was named ACI-2.

[0034] Example 9

[0035] The operation of Example 7 was the same, except that the amount of PAAM-4-10 (50% aqueous solution) was changed to 60 g, and the obtained composite corrosion inhibitor was named ACI-3.

[0036] Example 10

[0037] The operation of Example 7 was the same, except that the amount of PAAM-4-10 (50% aqueous solution) was changed to 80 g, and the obtained composite corrosion inhibitor was named ACI-4.

[0038] Example 11

[0039] The operation of Example 7 was the same, except that PAAM-4-10 (50% aqueous solution) was changed to PAAM-4-5, and the obtained composite corrosion inhibitor was named ACI-5.

[0040] Example 12

[0041] The same procedure as in Example 7 was followed except that PAAM-4-10 (50% aqueous solution) was replaced by PAAM-4-15 to obtain a complex corrosion inhibitor named ACI-6.

[0042] Example 13

[0043] The same procedure as in Example 7 was followed except that PAAM-4-10 (50% aqueous solution) was replaced by PAAM-2-10 to obtain a complex corrosion inhibitor named ACI-7.

[0044] Example 14

[0045] The same procedure as in Example 7 was followed except that PAAM-4-10 (50% aqueous solution) was replaced by PAAM-3-10 to obtain a complex corrosion inhibitor named ACI-8.

[0046] Example 15

[0047] The same procedure as in Example 7 was followed except that PAAM-4-10 (50% aqueous solution) was replaced by PAAM-5-10 to obtain a complex corrosion inhibitor named ACI-9.

[0048] Example 16

[0049] Take the industrial product (all the materials used below are industrial products unless otherwise specified) triethanolamine 150 g in a small solid mixer, add powdered sodium tripolyphosphate 500 g, HEDP 350 g, start the mixer to stir evenly, to obtain a complex washing agent.

[0050] Example 17

[0051] Take APG 1214 (50% aqueous solution) 40 g (equivalent to APG 20 g) in a container with stirring, add PEG 200 10 g, complex washing aid 30 g, corrosion inhibitor ACI-1 5 g, add appropriate amount of antioxidant (benzotriazole) and defoaming agent (B1016), add distilled water to a total weight of 250 g, stir to dissolve evenly to obtain a transparent aluminum alloy cleaning solution.

[0052] Take the prepared aluminum alloy cleaning agent 250 g, dilute with 4.75 kg of water. Add the diluted cleaning solution to a small ultrasonic cleaner and heat to 90°C. Place the aluminum alloy test piece with surface dirt in the cleaner and clean for 2 h. Test the cleaning effect and corrosion resistance. The cleaning degree is more than 99% and the surface color of the aluminum alloy does not change, with no visible corrosion spots.

[0053] Example 18

[0054] The procedure of Example 17 was followed except that the amount of water was changed to 2.25 kg. The test results showed that the cleaning efficiency was over 99%, the color of the aluminum alloy surface did not change, and no visible corrosion spots were observed.

[0055] Example 19

[0056] The procedure of Example 17 was followed except that the amount of water was changed to 1.0 kg. The test results showed that the cleaning efficiency was over 99%, the color of the aluminum alloy surface did not change, and no visible corrosion spots were observed.

[0057] Example 20

[0058] The procedure of Example 17 was followed except that the amount of APG 1214 was changed to 27 g and the amount of PEG 200 was changed to 6.5 g. The test results showed that the cleaning efficiency was over 95%, the color of the aluminum alloy surface did not change, and no visible corrosion spots were observed.

[0059] Example 21

[0060] The procedure of Example 17 was followed except that the amount of APG 1214 was changed to 50 g and the amount of PEG 200 was changed to 12.5 g. The test results showed that the cleaning efficiency was over 99%, the color of the aluminum alloy surface did not change, and no visible corrosion spots were observed.

[0061] Example 22

[0062] The procedure of Example 17 was followed except that the amount of the composite detergent additive was changed to 25 g. The test results showed that the cleaning efficiency was over 96%, the color of the aluminum alloy surface did not change, and only a few (less than 1 per cm 2 ) visible corrosion spots were observed.

[0063] Example 23

[0064] The procedure of Example 17 was followed except that the amount of the composite detergent additive was changed to 37.5 g. The test results showed that the cleaning efficiency was over 99%, the color of the aluminum alloy surface did not change, and no visible corrosion spots were observed.

[0065] Example 24

[0066] The procedure of Example 17 was followed except that the amount of the composite corrosion inhibitor PCI-1 was changed to 2.5 g. The test results showed that the cleaning efficiency was over 99%, the color of the aluminum alloy surface did not change, and only a few (less than 2 per cm 2 ) visible corrosion spots were observed.

[0067] Example 25

[0068] The procedure of Example 17 was followed except that the amount of the composite corrosion inhibitor PCI-1 was changed to 7.5 g. The test results showed that the cleanliness was over 99%, the color of the aluminum alloy surface did not change, and no visible corrosion spots were observed.

[0069] Example 26

[0070] The procedure of Example 17 was followed except that the washing temperature was changed to 20°C. The test results showed that the cleanliness was over 99%, the color of the aluminum alloy surface did not change, and no visible corrosion spots were observed.

[0071] Example 27

[0072] The procedure of Example 17 was followed except that the washing temperature was changed to 40°C. The test results showed that the cleanliness was over 99%, the color of the aluminum alloy surface did not change, and no visible corrosion spots were observed.

[0073] Example 28

[0074] The procedure of Example 17 was followed except that the washing temperature was changed to 60°C. The test results showed that the cleanliness was over 99%, the color of the aluminum alloy surface did not change, and no visible corrosion spots were observed.

[0075] Example 29

[0076] The procedure of Example 17 was followed except that the composite corrosion inhibitor ACI-1 was changed to ACI-2. The test results showed that the cleanliness was over 99%, the color of the aluminum alloy surface did not change, and only a few (less than 2 per cm 2 ) of very small corrosion spots were observed.

[0077] Example 30

[0078] The procedure of Example 17 was followed except that the composite corrosion inhibitor ACI-1 was changed to ACI-3. The test results showed that the cleanliness was over 99%, the color of the aluminum alloy surface did not change, and only a few (less than 1 per cm 2 ) of very small corrosion spots were observed.

[0079] Example 31

[0080] The procedure of Example 17 was followed except that the composite corrosion inhibitor ACI-1 was changed to ACI-4. The test results showed that the cleanliness was over 99%, the color of the aluminum alloy surface did not change, and only a few (less than 1 per cm 2 ) of very small corrosion spots were observed.

[0081] Example 32

[0082] The procedure of Example 17 was followed except that the corrosion inhibitor ACI-1 was replaced by ACI-5. The test results showed that the cleaning efficiency was over 99%, the color of the aluminum alloy surface did not change, and there were no visible tiny corrosion spots (less than 1 per cm 2 ).

[0083] Example 33

[0084] The procedure of Example 17 was followed except that the corrosion inhibitor ACI-1 was replaced by ACI-6. The test results showed that the cleaning efficiency was over 99%, the color of the aluminum alloy surface did not change, and there were no visible tiny corrosion spots (less than 1 per cm 2 ).

[0085] Example 34

[0086] The procedure of Example 17 was followed except that the corrosion inhibitor ACI-1 was replaced by ACI-7. The test results showed that the cleaning efficiency was over 99%, the color of the aluminum alloy surface did not change, and there were no visible tiny corrosion spots (less than 3 per cm 2 ).

[0087] Example 35

[0088] The procedure of Example 17 was followed except that the corrosion inhibitor ACI-1 was replaced by ACI-8. The test results showed that the cleaning efficiency was over 99%, the color of the aluminum alloy surface did not change, and there were no visible tiny corrosion spots (less than 1 per cm 2 ).

[0089] Example 36

[0090] The procedure of Example 17 was followed except that the corrosion inhibitor ACI-1 was replaced by ACI-9. The test results showed that the cleaning efficiency was over 99%, the color of the aluminum alloy surface did not change, and there were no visible tiny corrosion spots (less than 1 per cm 2 ).

[0091] Example 37

[0092] The cleaning solution prepared in Example 17 was diluted to 1%, and the BOD5 and CODcr were tested by standard methods, repeated 3 times, and the average BOD5 / CODcr was 0.85.

Claims

1. A special cleaning fluid for cleaning oil stains in the processing of aluminum alloy parts, which can replace hydrocarbon cleaning fluid, characterized in that: The preparation method of the special cleaning liquid is as follows: long-chain alkyl polyglycoside (APG) and oleic acid polyethylene glycol ester with good biodegradability are used as cleaning active components, low molecular weight acrylic acid-acrylamide copolymer is compounded with phytic acid as corrosion inhibitor, the polymerization degree of the low molecular weight acrylic acid-acrylamide copolymer is 5-15, triethanolamine, sodium tripolyphosphate, HEDP and the like are used as cleaning aids, and antioxidants, defoaming agents and other additives are added to prepare a special cleaning liquid for aluminum alloy parts through a composite process; wherein long-chain alkyl polyglycoside and oleic acid polyethylene glycol ester are used as cleaning active components, low molecular weight acrylic acid-acrylamide copolymer is compounded with phytic acid as corrosion inhibitor, the polymerization degree of the low molecular weight acrylic acid-acrylamide copolymer is 5-15, triethanolamine, sodium tripolyphosphate, HEDP and the like are used as cleaning aids, and antioxidants, defoaming agents and the like are added to prepare a special cleaning liquid for aluminum alloy parts through a composite process; The ratio of acid polyethylene glycol ester is 2:1, and the amount of detergent active components in the cleaning solution is 8-15%; the amount of detergent additive is 10-20%, and the detergent additive is composed of triethanolamine, sodium tripolyphosphate, and hydroxyethylidene diphosphine, and the compound ratio of the three is 3:10:7; the amount of corrosion inhibitor added to the cleaning solution is 1-3%, and the corrosion inhibitor is prepared by compounding low molecular weight acrylic acid-acrylamide copolymer and phytic acid, and the ratio of the two is 1-4:1, and then antioxidant, defoaming agent and distilled water are added to 100%.

2. The special cleaning fluid for cleaning oil stains in the processing of aluminum alloy parts according to claim 1 is a substitute for hydrocarbon cleaning fluid, characterized in that Biodegradable long-chain alkyl glycosides and polyethylene glycol oleate are used as the main active ingredients.

3. A special cleaning fluid for cleaning oil stains in the process of machining aluminum alloy parts as a substitute for hydrocarbon cleaning fluid according to claims 1 and 2, characterized in that The model of long-chain alkyl glycoside is APG1214, and the model of polyethylene glycol oleate is PEG200.

4. The special cleaning fluid for cleaning oil stains in the processing of aluminum alloy parts according to claim 1 is a substitute for hydrocarbon cleaning fluid, characterized in that The low molecular weight acrylic acid-acrylamide copolymer is prepared according to the following method: the molar ratio of acrylic acid to acrylamide is 2-5:1, azobisisobutyronitrile is used as an initiator, and purified water is used as a polymerization solvent.

5. The special cleaning fluid for cleaning oil stains in the processing of aluminum alloy parts as a substitute for hydrocarbon cleaning fluid according to claim 1 is characterized in that The concentration of the cleaning liquid is 5-20% (diluted 5-20 times with water), and the cleaning solution is washed for 20 minutes at a temperature of 20-80°. It will not corrode various aluminum alloy parts.