Anti-freezing composition as well as preparation method and application thereof

Abstract

The invention relates to the technical field of chemistry, in particular to an anti-freezing composition and an anti-freezing agent as well as a preparation method and application thereof. According to the invention, rhamnolipid is used as a surface active substance to be combined with the anti-freezing solution components such as ethylene glycol, polyacrylamide and polyvinyl alcohol, so that the functions of a surfactant and a metal corrosion inhibitor can be played at the same time, and the anti-freezing effect of the anti-freezing solution components such as ethylene glycol, polyacrylamide and polyvinyl alcohol can be further improved; the anti-freezing composition with a high anti-freezing effect and a high metal anti-corrosion effect is obtained, has a remarkable anti-corrosion effect on aluminum alloy, and can be applied to a cooling system of an aluminum alloy structure as an anti-freezing agent component, so that the corrosion condition of the cooling system can be greatly relieved; meanwhile, due to the excellent anti-freezing effect, the anti-freezing agent can be applied to a more extremely cold environment.

Description

Technical Field

[0001] The present invention relates to the field of chemical technology, specifically to an antifreeze composition, an antifreeze agent, and their preparation methods and applications. Background Art

[0002] For antifreeze agents in systems such as automotive internal combustion engine cooling systems, agricultural machinery, special equipment, and radio electronic equipment, they generally contain ethylene glycol, sodium tetraborate, alkali metal phosphates, alkali metal salts of 2-mercaptobenzothiazole, alkali metal silicates, alkali metal hydroxides, silicone defoamers, dyes, and water. The disadvantages of such antifreeze agents are their high corrosion activity towards structural materials. In addition, silicates reduce the chemical stability of the antifreeze, resulting in low heat exchange efficiency. Essentially, the closest to such antifreeze agents is a liquid composed of water, ethylene glycol, a corrosion inhibitor - sodium phosphate, potato dextrin, polyacrylamide, polyvinyl alcohol, and a surfactant Syntanol DS-10. It not only has high corrosion activity towards aluminum alloys used in the structure of the cooling system, but also the antifreeze effect needs to be improved and it cannot cope with extreme application scenarios. Summary of the Invention

[0003] In view of this, the technical problem to be solved by the present invention is to provide an antifreeze composition, an antifreeze agent, and their preparation methods and applications. The antifreeze composition provided by the present invention has high antifreeze and metal corrosion prevention effects.

[0004] The present application provides an antifreeze composition, which includes, by mass percentage:

[0005] 49% - 51% ethylene glycol;

[0006] 0.07% - 0.08% polyacrylamide;

[0007] 0.07% - 0.08% polyvinyl alcohol;

[0008] 0.04% - 0.15% rhamnolipid;

[0009] The balance being water.

[0010] The rhamnolipid described in the present invention is usually a product of a strain containing rhamnolipids (RL). This strain has the functions of a corrosion inhibitor and a surfactant. Using the product of this strain, that is, rhamnolipid, as a surfactant and combining it with antifreeze components such as ethylene glycol, polyacrylamide, and polyvinyl alcohol can simultaneously exert the functions of a surfactant and a metal corrosion inhibitor, and can further improve the antifreeze effect of antifreeze components such as ethylene glycol, polyacrylamide, and polyvinyl alcohol, obtaining an antifreeze composition with high antifreeze and metal corrosion prevention effects.

[0011] Specifically, the rhamnolipids of the present invention include 94% - 96% dirhamnolipids and 4% - 6% monorhamnolipids. In certain embodiments of the present invention, the rhamnolipids are composed of 95% dirhamnolipids and 5% monorhamnolipids. The rhamnolipids of the present invention belong to an anionic-nonionic mixed surfactant, do not pollute the environment, and are easily soluble in water and ethylene glycol. Using RL in antifreeze components such as ethylene glycol, polyacrylamide, and polyvinyl alcohol helps to inhibit the corrosion process, which is due to the molecular orientation adsorption and the formation of a protective film resulting in the hydrophobicity of the metal surface. As a biosurfactant, RL also helps to remove dirt on the heat exchange surface and prevent fouling.

[0012] Preferably, the antifreeze composition of the present invention comprises:

[0013] 49% - 51% ethylene glycol;

[0014] 0.07% - 0.08% polyacrylamide;

[0015] 0.07% - 0.08% polyvinyl alcohol;

[0016] 0.06% - 0.12% rhamnolipids;

[0017] The balance is water.

[0018] More preferably, the antifreeze composition of the present invention comprises:

[0019] 50% ethylene glycol;

[0020] 0.075% polyacrylamide;

[0021] 0.075% polyvinyl alcohol;

[0022] 0.06% - 0.12% rhamnolipids;

[0023] The balance is water.

[0024] In one embodiment of the present invention, the antifreeze composition of the present invention comprises:

[0025] 50% ethylene glycol;

[0026] 0.075% polyacrylamide;

[0027] 0.075% polyvinyl alcohol;

[0028] 0.06% rhamnolipids;

[0029] The balance is water.

[0030] The present invention also provides a preparation method of the antifreeze composition according to any one of the above technical solutions, comprising the following steps: mixing ethylene glycol, polyacrylamide, polyvinyl alcohol, rhamnolipid and water to obtain the antifreeze composition. Specifically, in ethylene glycol and water, polyacrylamide, polyvinyl alcohol and rhamnolipid are sequentially added and mixed and dissolved to obtain the antifreeze composition. The mixing and dissolving in the present invention is carried out at 40°C to 50°C, preferably at 45°C, which helps to dissolve the materials evenly faster.

[0031] The present invention also provides an antifreeze, which is the antifreeze composition according to any one of the above technical solutions; or, it comprises an additive and the antifreeze composition according to any one of the above technical solutions; the additive is not particularly limited and is a conventional additive in the art that can be used in antifreezes.

[0032] The present invention also provides an application of the antifreeze composition according to any one of the above technical solutions as an antifreeze component in a cooling system of a metal structure. The antifreeze composition in the present invention has a significant anti-corrosion effect on aluminum alloy. Specifically, the present invention provides an application of the antifreeze composition according to any one of the above technical solutions as an antifreeze component in a cooling system of an aluminum alloy structure. More specifically, the present invention provides an application of the antifreeze composition according to any one of the above technical solutions as an antifreeze component in a cooling system of a 6063 aluminum alloy structure.

[0033] The present invention provides an antifreeze composition, an antifreeze, and their preparation methods and applications. The present invention combines rhamnolipid as a surface active substance with antifreeze components such as ethylene glycol, polyacrylamide and polyvinyl alcohol, which can simultaneously play the functions of a surfactant and a metal corrosion inhibitor, and can further improve the antifreeze effect of antifreeze components such as ethylene glycol, polyacrylamide and polyvinyl alcohol, to obtain an antifreeze composition with high antifreeze effect and metal anti-corrosion effect. The antifreeze composition has a significant anti-corrosion effect on aluminum alloy. When applied as an antifreeze component in a cooling system of an aluminum alloy structure, it can greatly alleviate the corrosion of the cooling system. At the same time, its excellent antifreeze effect enables it to be applied in a more extremely cold environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Micrograph of the refrigerant of Comparative Example 1 when the temperature reaches -65°C;

[0035] Figure 2 Micrograph of the refrigerant of Comparative Example 2 when the temperature reaches -45°C;

[0036] Figure 3 Micrograph of the refrigerant of Example 6 when the temperature reaches -85°C. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention discloses an antifreeze composition, an antifreeze agent, and their preparation methods and applications. Those skilled in the art can draw on the content of this article and appropriately improve the process parameters to achieve. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and those skilled in the art can clearly make changes, or appropriate changes and combinations to the methods and applications in this article without departing from the content, spirit, and scope of the present invention to implement and apply the technology of the present invention.

[0038] The present invention will be further elaborated with reference to the following examples:

[0039] Examples 1 - 5

[0040] Using ethylene glycol, distilled water, polyacrylamide, polyvinyl alcohol, and rhamnolipids (purchased from Sigma - Aldrich, with a solid content of 95%) purchased from the company as starting materials for preparing the coolant, in the water - ethylene glycol solution, polyacrylamide, polyvinyl alcohol, and rhamnolipids were added in sequence and stirred to dissolve to obtain the refrigerant. To accelerate the dissolution process, the liquid temperature was raised to 45°C. The composition and quantitative composition of the refrigerants in Examples 1 - 5 are shown in Table 1:

[0041] Table 1

[0042]

[0043] Corrosion electrochemistry tests were carried out on 6063 aluminum alloy plates in the coolants of Examples 2 - 4. Specifically, the methods of potentiodynamic polarization and electrochemical impedance spectroscopy were used, and the research results are shown in Table 2.

[0044] Table 2

[0045]

[0046] It can be seen that the corrosion of the aluminum alloy in the proposed coolant is much less than that in the prototype fluid. At the same time, the corrosion current of the alloy decreased by 2.25 - 3.0 times, and the charge transfer resistance increased from 3×10 4 Ohm×cm 2 to 1.3×10 5 Ohm×cm 2 . In this way, a significant anti - corrosion effect of the proposed coolant on the aluminum alloy is achieved. The coolant proposed by the present invention is easy to manufacture, and any chemical enterprise can produce it.

[0047] Comparative Example 1

[0048] In a water-ethylene glycol solution, polyacrylamide and polyvinyl alcohol were added sequentially and stirred to dissolve, obtaining a refrigerant. To accelerate the dissolution process, the liquid temperature was raised to 45 °C. In terms of mass percentage, the composition and quantitative composition of the refrigerant prepared in this comparative example are as follows:

[0049] Ethylene glycol: 50%;

[0050] Polyacrylamide: 0.075%;

[0051] Polyvinyl alcohol: 0.075%;

[0052] Distilled water: 49.85%.

[0053] Comparative Example 2

[0054] In a water-ethylene glycol solution, polyacrylamide, polyvinyl alcohol and DEA (N,N-bis(hydroxyethyl)coconut amide) were added sequentially and stirred to dissolve, obtaining a refrigerant. To accelerate the dissolution process, the liquid temperature was raised to 45 °C. In terms of mass percentage, the composition and quantitative composition of the refrigerant prepared in this comparative example are as follows:

[0055] Ethylene glycol: 50%;

[0056] Polyacrylamide: 0.075%;

[0057] Polyvinyl alcohol: 0.075%;

[0058] DEA: 0.06%;

[0059] Distilled water: 49.79%.

[0060] Example 6

[0061] In a water-ethylene glycol solution, polyacrylamide, polyvinyl alcohol and RL with a mass concentration of 40% were added sequentially and stirred to dissolve, obtaining a refrigerant. To accelerate the dissolution process, the liquid temperature was raised to 45 °C. In terms of mass percentage, the composition and quantitative composition of the refrigerant prepared in this comparative example are as follows:

[0062] Ethylene glycol: 50%;

[0063] Polyacrylamide: 0.075%;

[0064] Polyvinyl alcohol: 0.075%;

[0065] Rhamnolipid (in 100% purity): 0.06%;

[0066] Distilled water: 49.79%.

[0067] The freezing point tests were carried out on the refrigerants obtained from the above Comparative Example 1, Comparative Example 2 and Example 6, and the results are asFigures 1 to 3 As shown Figure 1 is the micrograph of the refrigerant of Comparative Example 1 when the temperature reaches -65°C, Figure 2 is the micrograph of the refrigerant of Comparative Example 2 when the temperature reaches -45°C, Figure 3 is the micrograph of the refrigerant of Example 6 when the temperature reaches -85°C. From Figure 1 it can be seen that when the temperature reaches -65°C, the refrigerant begins to solidify and freeze. Therefore, the freezing point of the refrigerant of Comparative Example 1 is measured to be approximately -65°C; from Figure 2 it can be seen that when the temperature reaches -45°C, the refrigerant begins to solidify and freeze. Therefore, the freezing point of the refrigerant of Comparative Example 2 is measured to be approximately -45°C; from Figure 3 it can be seen that when the temperature reaches -85°C, the refrigerant begins to solidify and freeze. Therefore, the freezing point of the refrigerant of Example 6 is measured to be approximately -85°C.

[0068] The above is only the preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. An antifreeze composition, characterized in that In terms of mass percentage, it includes: 49%~51% ethylene glycol; 0.07%~0.08% polyacrylamide; 0.07%~0.08% polyvinyl alcohol; 0.04%~0.15% rhamnolipid; The remaining amount of water.

2. The antifreeze composition according to claim 1, characterized in that The rhamnolipids include 94% to 96% di-rhamnolipids and 4% to 6% mono-rhamnolipids.

3. The antifreeze composition according to claim 2, characterized in that The rhamnolipid is composed of 95% di-rhamnolipid and 5% mono-rhamnolipid.

4. The antifreeze composition according to any one of claims 1 to 3, characterized in that It includes: 49%~51% ethylene glycol; 0.07%~0.08% polyacrylamide; 0.07%~0.08% polyvinyl alcohol; 0.06%~0.12% rhamnolipid; The remaining amount of water.

5. The antifreeze composition according to any one of claims 1 to 3, characterized in that It includes: 50% ethylene glycol; 0.075% polyacrylamide; 0.075% polyvinyl alcohol; 0.06%~0.12% rhamnolipid; The remaining amount of water.

6. The antifreeze composition according to any one of claims 1 to 3, characterized in that It includes: 50% ethylene glycol; 0.075% polyacrylamide; 0.075% polyvinyl alcohol; 0.06% rhamnolipid; The remaining amount of water.

7. The method for preparing the antifreeze composition according to any one of claims 1 to 6, characterized in that: The following steps are involved: Ethylene glycol, polyacrylamide, polyvinyl alcohol, rhamnolipid and water are mixed to obtain an antifreeze composition.

8. Antifreeze agent, characterized in that It is the antifreeze composition according to any one of claims 1 to 6; or it comprises an additive and the antifreeze composition according to any one of claims 1 to 6.

9. Use of the antifreeze composition according to any one of claims 1 to 6 as an antifreeze component in a cooling system of a metal structure.

10. The use according to claim 9, characterized in that: The metal is an aluminum alloy.

Images