Environment-friendly rolling liquid as well as preparation method and application thereof

Abstract

The present application relates to a kind of environment-friendly rolling liquid and its preparation method and application, the environment-friendly rolling liquid according to mass percentage content, including the following components: water-soluble polyether 10-90%, organic amine soap 0.1-5%, lithium clay / polyacrylic acid / poly N-isopropyl acrylamide nanocomposite 2-10%, metal deactivator 0.1-2%, antioxidant 0.1-2%, wetting agent 0.1-2%, the rest is water.The environment-friendly rolling liquid provided in the present application uses water-soluble polyether and lithium clay / polyacrylic acid / poly N-isopropyl acrylamide nanocomposite synergistic effect, replaces traditional lubricating component base oil, can reach good cooling performance, lubricating property and antirust performance under water-based system, easy to clean, resistant to oil resistance antibacterial, and environment-friendly.

Description

Technical Field

[0001] This invention relates to the field of metalworking fluid technology, specifically to an environmentally friendly rolling fluid, its preparation method, and its application. Background Technology

[0002] Hot rolling is the first and crucial plastic forming process in the production of aluminum and aluminum alloy sheets and strips. Its purpose is to break down the coarse grain structure after casting, refine the grains, eliminate casting defects, and form a dense fibrous structure, thereby significantly improving the mechanical properties of aluminum and obtaining billets of approximately the dimensions required for subsequent cold rolling processes.

[0003] Currently, a typical aluminum hot rolling process mainly includes two stages—hot roughing and hot finishing. Hot roughing refers to rolling a heated ingot (typically 400-600mm thick) through a reversible rolling mill in multiple passes to produce a slab with a thickness of 20-40mm. However, each pass involves a large reduction, high rolling force, and concentrated deformation and frictional heat. Hot finishing refers to rolling the hot-roughened slab into coils with a thickness of 2-6mm through a continuous multi-stand hot finishing mill. However, this involves high rolling speeds (up to 600m / min or more) and stringent requirements for sheet shape and surface quality.

[0004] Therefore, the current hot rolling process has stringent requirements for the rolling fluid. During the high-speed, high-pressure hot rolling process, the rolls and aluminum materials undergo severe friction and plastic deformation, generating a large amount of deformation heat and frictional heat, which causes the temperature of the rolls and aluminum materials to rise sharply. In order to ensure the smooth progress of the process and obtain high-quality products, the rolling fluid must simultaneously meet the following four functions, and they are interrelated and mutually restrictive: (1) Cooling performance: First, control the roll temperature to prevent the rolls from overheating and causing thermal fatigue cracks (thermal cracking), which affects the roll life and surface quality; Second, control the material temperature to prevent the aluminum material temperature from being too high and causing coarse grains, overheating (low melting point eutectic melting), or even "sticking to the roll" phenomenon; Third, ensure the plate shape. Uniform and efficient cooling is the key to ensuring the uniform thickness of the aluminum strip in the transverse and longitudinal directions. Uneven cooling will lead to poor plate shape, such as waviness and warping. (2) Lubrication performance: Firstly, it reduces rolling force and energy consumption, and reduces friction between the rolls and aluminum, thereby reducing rolling force and drive power consumption; secondly, it improves surface quality and prevents defects such as scratches, adhesion, and orange peel on the surface of aluminum. Good lubrication is a prerequisite for obtaining a bright and uniform surface; thirdly, it protects the rolls, reduces roll wear, and extends their service life. (3) Cleaning performance: Fine aluminum chips (aluminum powder) and oxides are generated during hot rolling. The rolling fluid must be able to effectively flush away these particles to prevent them from accumulating on the roll surface or damaging the aluminum surface, causing pressing defects. (4) Rust prevention performance: Although aluminum itself is not easy to rust, its alloying elements (such as copper, magnesium, and silicon) and rolling mill equipment (steel material) are extremely easy to corrode under high temperature and high humidity conditions. Therefore, the rolling fluid needs to provide short-term anti-oxidation protection for aluminum and rust prevention protection for the rolling mill system.

[0005] Currently, in the field of lubricating oil and metalworking fluid, "base oil" refers to a liquid hydrocarbon mixture that is not blended with functional additives and constitutes the main body of the lubricant. It usually accounts for more than 60-90% of the formula. According to the raw materials and processes, it can be divided into three categories: (1) Mineral oil base oil, which is refined from crude oil through a series of processes such as atmospheric and vacuum distillation, solvent refining, solvent dewaxing, and hydrogenation supplementary refining. It is mainly a mixture containing alkanes (paraffinic), cycloalkanes and aromatics. It has low cost and many impurities and only meets the requirements of conventional lubrication. (2) Synthetic base oil, which is prepared by organic synthesis methods (such as olefin polymerization, esterification reaction, etc.). The molecular structure is designed, such as PAO, diester, polyol ester, polyether, etc. It has a simple structure and excellent high and low temperature performance. (3) Vegetable oil base oil, which is derived from natural triglycerides such as rapeseed, soybean, and palm. It is renewable, easily biodegradable and has good initial lubricity. However, due to its rich unsaturated double bonds, it has poor oxidation and hydrolysis stability, is prone to sludge and rancidity, has a short life and is difficult to maintain.

[0006] In summary, the following problems exist with rolling fluids containing base oil: (1) Systemic deterioration of the problem of mixed oil leakage. Modern high-speed rolling mills use a large amount of lubricating esters and hydraulic oils (collectively referred to as "mixed oils") in bearings, gearboxes, hydraulic systems, etc. These mixed oils are compatible with the base oil in the system, changing the saponification value and stability of the original system, reducing lubricity and emulsification stability. The metal ions and oxidation products carried by the mixed oils pollute the entire system, requiring frequent use of centrifuges, skimmers and other equipment for oil removal, increasing energy consumption and maintenance costs, and are difficult to completely remove. (2) Exacerbation of the problem of microbial growth. The putrefaction of rolling fluid produces H2S with a rotten egg smell, which deteriorates the working environment; fungi form biofilms and slime, clogging filters and pipelines, affecting the flow and uniformity of cooling nozzles, directly leading to plate shape problems, and even making normal rolling impossible; microbial metabolism produces acidic substances, affecting the indicators and performance of the working fluid, and in severe cases, even corroding the rolls, pipes and aluminum surfaces, causing equipment damage and product surface contamination; the aerosols formed may affect the respiratory health of workers. (3) Environmental protection and cost pressures. Mineral oil poses certain hazards to human health and the environment. Oily waste liquid is difficult to treat and expensive, with disposal costs constantly rising. The shortened lifespan of rolling fluid due to contamination by mixed oils and microbial decay increases the total production cost of purchasing new fluid and treating waste liquid.

[0007] Therefore, existing base oil-based rolling fluids suffer from bottlenecks in system maintenance costs and environmental friendliness. Developing a base oil-free rolling fluid is a technical problem that needs to be solved. Summary of the Invention

[0008] To address the above problems, the present invention aims to provide an environmentally friendly rolling fluid, its preparation method, and its application. Compared with the prior art, the environmentally friendly rolling fluid provided by the present invention uses water-soluble polyether and lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite materials in a synergistic effect to replace the traditional lubricating component base oil. It can achieve good cooling performance, lubrication performance, and rust prevention performance in a water-based system, is easy to clean, resistant to impurities and bacteria, and is environmentally friendly.

[0009] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides an environmentally friendly rolling fluid, which comprises, by weight percentage, the following components: 10-90% water-soluble polyether, 0.1-5% organic amine soap, 2-10% lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, 0.1-2% metal deactivating agent, 0.1-2% antioxidant, 0.1-2% wetting agent, and the balance being water.

[0010] The environmentally friendly rolling fluid system provided by this invention uses water-soluble polyether as the lubricating component instead of traditional base oil, and employs lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. This nanocomposite material is a temperature / pressure responsive nanocomposite material, which changes from a sol state to a gel state in the roll gap region under high temperature and high pressure (generally, the industry estimates the temperature of the roll gap region to be 120-300℃ and the pressure to be 1-2GPa based on experience). It has excellent mechanical properties and can enhance the lubrication effect. It avoids the use of traditional phosphorus and sulfur-containing extreme pressure additives, which is both environmentally friendly and solves the problem that traditional phosphorus and sulfur-containing extreme pressure additives cannot be compounded with water-based systems.

[0011] The environmentally friendly rolling fluid formulation of this invention does not contain base oil, a liquid medium that is mainly composed of mineral oil, vegetable oil, or hydrophobic synthetic hydrocarbons and is insoluble in water. This invention uses water-soluble polyether instead of traditional base oil and introduces temperature / pressure responsive nanocomposite materials into the rolling fluid. This allows water to replace oil as the continuous phase, achieving a leap in system performance. It exhibits better cooling, cleaning, lubrication, and rust prevention properties, while also providing resistance to impurities and bacteria, and long-lasting environmental protection. This fundamentally solves the problems of susceptibility to impurities and microbial growth caused by the presence of base oil, extending its service life and reducing usage and maintenance costs.

[0012] In this invention, the water-soluble polyether is 10-90%, for example, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%, but is not limited to the listed values; other values ​​within the range not listed are also applicable. The organic amine soap is 0.1-5%, for example, it can be 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or 5%, but is not limited to the listed values; other values ​​within the range not listed are also applicable. The lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is 2-10%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, but is not limited to the listed values; other values ​​within the range not listed are also applicable. The same applies; metal deactivators are 0.1-2%, for example, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, or 2%, but not limited to the listed values, and other unlisted values ​​within the range are also applicable; antioxidants are 0.1-2%, for example, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, or 2%, but not limited to the listed values, and other unlisted values ​​within the range are also applicable; wetting agents are 0.1-2%, for example, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, or 2%, but not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0013] Preferably, the water-soluble polyether comprises an EO-PO block polyether.

[0014] Preferably, the weight-average molecular weight of the EO-PO block polyether is 2000-10000, for example, it can be 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500 or 10000, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0015] In this invention, the EO-PO block polyether can be any polyether available in the art, commercially available, and can be a single polyether meeting the required weight-average molecular weight, or a blend of multiple polyethers can be used to achieve the required weight-average molecular weight. Specifically, when multiple polyethers are blended, the following combinations are included, but are not limited to: for example, using a blend of BASFPluronic PE9200 and BASF Pluronic PE6800 with a mass ratio of (0.8-1.2):1; using a blend of BASFPluronic PE2525 and BASF Pluronic PE6800 with a mass ratio of (0.8-1.2):2; when using a single polyether, for example, BASF Pluronic PE 9200.

[0016] Preferably, the organic amine soap is prepared using organic acids and organic amines.

[0017] Preferably, the organic acid includes a monobasic acid and / or a dibasic acid.

[0018] Preferably, the monocarboxylic acid includes any one or a combination of at least two of nonanoic acid, isononanoic acid, octanoic acid, heptanoic acid, decanoic acid, neodecanoic acid, lauric acid, coconut oil acid, palmitic acid, or stearic acid.

[0019] Preferably, the dicarboxylic acid includes any one or a combination of at least two of sebacic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, or octadecanoic acid.

[0020] Preferably, the organic amine includes an alcohol amine containing a hydroxyl group.

[0021] Preferably, the organic amine includes any one or a combination of at least two of monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, or triisopropanolamine.

[0022] Preferably, the molar ratio of the carboxyl group in the organic acid to the amino group in the organic amine is 1:(1-1.6), for example, it can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or 1:6, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material uses XLG-type lithium diatomite.

[0024] Preferably, the molecular formula of the lithium diatomite is: .

[0025] Preferably, the lithium diatomite comprises nanoscale flake-shaped lithium diatomite.

[0026] Preferably, the diameter of the lithium diatomite is 20-30 nm, for example, it can be 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm or 30 nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] Preferably, the thickness of the lithium diatomite is 0.8-1.2 nm, for example, it can be 0.8 nm, 0.9 nm, 1.0 nm, 1.1 nm or 1.2 nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] In this invention, the lithium diatomite can be commercially available XLG-type lithium diatomite, such as LAPONITE XLG purchased from Rockwood, with the molecular formula [missing information]. Lithium diatomite is a well-structured layered silicate containing hydroxyl groups, exhibiting good dispersibility in water. The edges of lithium diatomite are positively charged, while the planar surface is negatively charged. Polyacrylic acid is adsorbed onto the positively charged edges of the lithium diatomite sheets through electrostatic interactions, further enhancing its dispersibility in the aqueous phase. Due to the dipole force, the amide groups of the N-isopropylacrylamide monomer exhibit positive charge, allowing them to interact with the negatively charged planar surface of the lithium diatomite sheets, improving mechanical properties. Through atom transfer radical polymerization, the N-isopropylacrylamide monomer is introduced to form a three-dimensional network structure. The structural formula of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite is as follows: .

[0029] Preferably, the polyacrylic acid used in the lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material has a weight-average molecular weight of 5,000-250,000, for example, it can be 5,000, 6,000, 7,000, 8,000, 9,000, 10,000, 20,000, 30,000, 40,000, 50,000, 60,000, 70,000, 80,000, 90,000, 100,000, 110,000, 120,000, 130,000, 140,000, 150,000, 160,000, 170,000, 180,000, 190,000, 200,000, 220,000, or 250,000, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the preparation method of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material includes the following steps: Lithium diatomite, polyacrylic acid, and water were mixed, and then N-isopropylacrylamide monomer, crosslinking agent, initiator, and auxiliaries were added. The mixture was then reacted and dried sequentially to obtain lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material.

[0031] Preferably, the raw materials for preparing the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, by weight, include 5-10 parts lithium diatomite, 0.1-0.5 parts polyacrylic acid, 10-20 parts N-isopropylacrylamide monomer, 0.02-0.03 parts crosslinking agent, 0.3-0.5 parts initiator, 0.02-0.04 parts additives, and 15-25 parts water.

[0032] Preferably, the crosslinking agent comprises N,N'-methylenebisacrylamide.

[0033] Preferably, the initiator comprises potassium persulfate.

[0034] Preferably, the adjuvant comprises tetramethylethylenediamine.

[0035] Preferably, the mixing and reaction are carried out under a nitrogen atmosphere.

[0036] Preferably, the reaction temperature is 0-8℃, for example, it can be 0℃, 1℃, 2℃, 3℃, 4℃, 5℃, 6℃, 7℃ or 8℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0037] Preferably, stirring is performed during the reaction.

[0038] Preferably, the reaction time is 4-12 hours, for example, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] Preferably, the drying temperature is 40-80℃, for example, it can be 40℃, 45℃, 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, 62℃, 64℃, 66℃, 68℃, 70℃, 75℃ or 80℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0040] Preferably, the drying time is 8-72 hours, for example, it can be 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, 45 hours, 50 hours, 55 hours, 60 hours, 65 hours, 70 hours or 72 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0041] Preferably, the weight-average molecular weight of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is 5000-15000, for example, it can be 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000 or 15000, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0042] In this invention, by optimally controlling the weight-average molecular weight of the lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, it is possible to meet mechanical performance requirements without affecting its solubility, thus avoiding negative impacts. When the weight-average molecular weight is too low, it can easily lead to insufficient lubrication; when the weight-average molecular weight is too high, it can easily lead to problems such as residual stains on the surface of the rolled sheet.

[0043] Preferably, the critical dissolution temperature of the aqueous solution of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material with a mass concentration of 1% is ≥50°C, for example, it can be 50°C, 52°C, 54°C, 56°C, 58°C or 60°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0044] In this invention, the method for testing the critical dissolution temperature is as follows: Take an aqueous solution of lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material with a mass concentration of 1% into a beaker, heat it at 3℃ / min and stir continuously. When turbidity first appears near the bottom of the beaker, it indicates that the critical dissolution temperature is approaching. Continue heating until the sample is completely turbid and remains so. Record the temperature to an accuracy of 1℃.

[0045] In this invention, the critical dissolution temperature is the temperature threshold at which phase separation occurs in the nanocomposite material during heating. By controlling the range of the critical dissolution temperature, this invention ensures that the rolling fluid remains stable in the working environment (e.g., 45-60℃), meeting the industry's performance requirements for the rolling fluid. When the rolling fluid transforms from a sol state to a gel state in the roll gap region under high temperature and high pressure (e.g., 120-300℃, pressure 1-2 GPa), it provides a lubricating effect. It should be noted that when the critical dissolution temperature is too low (e.g., 35℃), the rolling fluid is prone to precipitation in the working environment, affecting its performance and failing to meet the industry's requirements for rolling fluid use.

[0046] Preferably, the metal deactivator includes benzotriazoles.

[0047] Preferably, the antioxidant comprises 2,6-di-tert-butyl-p-cresol.

[0048] In this invention, the wetting agent can be a commonly used wetting agent in the art, such as Clariant Dispersogen PLF100.

[0049] Secondly, the present invention provides a method for preparing an environmentally friendly rolling fluid as described in the first aspect of the present invention, the method comprising: An environmentally friendly rolling solution is obtained by mixing water-soluble polyether, organic acid, organic amine, lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, metal deactivator, antioxidant, wetting agent and water.

[0050] The preparation method provided by this invention involves mixing water-soluble polyether, organic acid, organic amine, lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, metal deactivator, antioxidant, wetting agent and water to obtain a rolling fluid with good cooling and lubrication effects under base oil-free conditions.

[0051] Thirdly, the present invention provides an application of the environmentally friendly rolling fluid as described in the first aspect of the present invention, wherein the environmentally friendly rolling fluid is used for hot rolling of aluminum or aluminum alloys.

[0052] The rolling fluid provided by this invention is used for hot rolling of aluminum or aluminum alloys, including hot roughing and hot finishing. It can achieve good cooling performance, lubrication performance and rust prevention performance, is easy to clean, resists impurities and bacteria, and is environmentally friendly.

[0053] Compared with the prior art, the present invention has the following beneficial effects: (1) The environmentally friendly rolling fluid provided by this invention uses lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. In the roll gap area under high temperature and high pressure, the polyN-isopropylacrylamide segments / lithium diatomaceous earth have temperature / pressure sensitive response. The nanocomposite material precipitates from a sol state to a gel state, thereby providing sufficient lubrication performance. It is also reversible, and can return to the rolling fluid after passing through the rolling zone without affecting subsequent cleaning. It avoids the use of traditional P and S-containing extreme pressure additives, making it environmentally friendly.

[0054] (2) The environmentally friendly rolling fluid provided by the present invention uses lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. Polyacrylic acid is adsorbed on the positive charge edge of lithium diatomite sheet through electrostatic interaction, which improves its dispersibility in the aqueous phase and solves the problem that traditional extreme pressure additives cannot be compounded into the water-based system.

[0055] (3) The environmentally friendly rolling fluid provided by the present invention uses lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material and water-soluble polyether to achieve a leap in system performance under the condition of no base oil. It has better cooling performance, cleaning performance, lubrication performance and rust prevention performance. At the same time, it achieves anti-mixed oil and antibacterial properties, long-term environmental protection, fundamentally solving the problems of easy contamination by mixed oil and easy growth of microorganisms caused by the presence of base oil, extending its service life and reducing the cost of use and maintenance.

[0056] (4) Under optimal conditions, the environmentally friendly rolling fluid provided by the present invention can achieve an average film thickness of more than 143 nm, an average friction coefficient of less than 0.1, a corrosion area of ​​less than 10% in the water corrosion test, and a duration of more than 6 weeks in the antibacterial performance test. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the three-dimensional network formed by the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material in Example 1 of the present invention. Detailed Implementation

[0058] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0059] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0060] Example 1 This embodiment provides an environmentally friendly rolling fluid, which comprises the following components by mass percentage: 50% EO-PO block polyether, 2.5% organic amine soap, 6% lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, 1% benzotriazole, 1% 2,6-di-tert-butyl-p-cresol, 1% Clariant Dispersogen PLF 100, and the balance being water.

[0061] The above-mentioned EO-PO block polyether is a mixture of two polyethers in a mass ratio of 1:1: 1) BASF Pluronic PE9200, with a weight-average molecular weight of 3650; 2) BASF Pluronic PE6800, with a weight-average molecular weight of 8000. The above-mentioned organic amine soap is obtained by reacting neodecanoic acid and triethanolamine, with a molar ratio of carboxyl groups in neodecanoic acid to amino groups in triethanolamine of 1:1.3.

[0062] The above-mentioned lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material has a weight-average molecular weight of 8000. The critical dissolution temperature of an aqueous solution of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material with a mass concentration of 1% is 55℃. The preparation method includes: mixing 7.5 parts of lithium diatomite, 0.5 parts of polyacrylic acid, and 20 parts of water in a three-necked flask, stirring under a nitrogen atmosphere, then adding 15 parts of N-isopropylacrylamide monomer, 0.02 parts of N,N'-methylenebisacrylamide, 0.5 parts of potassium persulfate, and 0.03 parts of tetramethylethylenediamine. The mixture is stirred at 2℃ in an ice bath for 8 hours, transferred to a beaker, and dried at 60℃ for 40 hours to obtain the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. The lithium diatomite was purchased from Rockwood's LAPONITE XLG, with the molecular formula [missing information]. The diameter is 20-30 nm, the thickness is 1 nm, the weight average molecular weight of polyacrylic acid is 5000, and it is purchased from Sigma-Aldrich. N-isopropylacrylamide, potassium persulfate and tetramethylethylenediamine are purchased from Aladdin.

[0063] like Figure 1 As shown, lithium diatomite is a structurally regular layered silicate, i.e., nanoscale sheet-like lithium diatomite. It contains hydroxyl groups and exhibits good dispersibility in water. The edges of the lithium diatomite are positively charged, while the planes are negatively charged. Polyacrylic acid is adsorbed onto the positively charged edges of the lithium diatomite sheets through electrostatic interactions, further enhancing its dispersibility in the aqueous phase. Due to the effect of dipole forces, the amide groups of the N-isopropylacrylamide monomer exhibit positive charge, thus interacting with the negatively charged lithium diatomite sheet planes to improve mechanical properties. Through atom transfer radical polymerization, poly(N-isopropylacrylamide) is generated, forming a three-dimensional network structure.

[0064] This embodiment also provides a method for preparing the above-mentioned environmentally friendly rolling fluid, the preparation method comprising: According to the formulation, EO-PO block polyether, neodecanoic acid, triethanolamine, lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, benzotriazole, 2,6-di-tert-butyl-p-cresol, Clariant Dispersogen PLF 100 and water are mixed to obtain an environmentally friendly rolling solution.

[0065] Example 2 This embodiment provides an environmentally friendly rolling fluid, which comprises the following components by mass percentage: 15% EO-PO block polyether, 0.1% organic amine soap, 10% lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, 2% benzotriazole, 0.1% 2,6-di-tert-butyl-p-cresol, 2% Clariant Dispersogen PLF 100, and the balance being water.

[0066] The above-mentioned EO-PO block polyether is a mixture of two polyethers in a mass ratio of 1:2: 1) BASF Pluronic PE2525, with a weight-average molecular weight of 2000; 2) BASF Pluronic PE6800, with a weight-average molecular weight of 8000. The above-mentioned organic amine soap is obtained by reacting isononanoic acid and triethanolamine, with a molar ratio of carboxyl groups in isononanoic acid to amino groups in triethanolamine of 1:1.

[0067] The above-mentioned lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material has a weight-average molecular weight of 12000. The critical dissolution temperature of an aqueous solution of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material with a mass concentration of 1% is 70℃. The preparation method includes: mixing 10 parts of lithium diatomite, 0.2 parts of polyacrylic acid, and 20 parts of water in a three-necked flask, stirring under a nitrogen atmosphere, then adding 10 parts of N-isopropylacrylamide monomer, 0.02 parts of N,N'-methylenebisacrylamide, 0.3 parts of potassium persulfate, and 0.02 parts of tetramethylethylenediamine. The mixture is stirred at 0℃ in an ice bath for 4 hours, transferred to a beaker, and dried at 50℃ for 72 hours to obtain the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. The lithium diatomite was purchased from Rockwood's LAPONITE XLG, with the molecular formula [missing information]. The diameter is 20-30nm, the thickness is 1nm, the weight average molecular weight of polyacrylic acid is 100,000, and it is purchased from Sigma-Aldrich. N-isopropylacrylamide, potassium persulfate and tetramethylethylenediamine are purchased from Aladdin.

[0068] This embodiment also provides a method for preparing the above-mentioned environmentally friendly rolling fluid, the preparation method comprising: According to the formulation, EO-PO block polyether, isononanoic acid, triethanolamine, lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, benzotriazole, 2,6-di-tert-butyl-p-cresol, Clariant Dispersogen PLF 100 and water are mixed to obtain an environmentally friendly rolling solution.

[0069] Example 3 This embodiment provides an environmentally friendly rolling fluid, which comprises the following components by mass percentage: 90% EO-PO block polyether, 5% organic amine soap, 2% lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, 0.1% benzotriazole, 2% 2,6-di-tert-butyl-p-cresol, 0.1% Clariant Dispersogen PLF 100, and the balance being water.

[0070] The aforementioned EO-PO block polyether is BASF Pluronic PE 9200, with a weight-average molecular weight of 3650. The aforementioned organic amine soap is obtained by reacting neodecanoic acid, isononanoic acid, and triethanolamine, with a molar ratio of neodecanoic acid to isononanoic acid of 1:1, and a molar ratio of carboxyl groups in neodecanoic acid and isononanoic acid to amino groups in triethanolamine of 1:1.6.

[0071] The lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material has a weight-average molecular weight of 10,000. The critical dissolution temperature of a 1% (w / w) aqueous solution of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is 60°C. The preparation method includes: mixing 7.5 parts lithium diatomite, 0.1 parts polyacrylic acid, and 20 parts water in a three-necked flask, stirring under a nitrogen atmosphere, then adding 15 parts N-isopropylacrylamide monomer, 0.02 parts N,N'-methylenebisacrylamide, 0.4 parts potassium persulfate, and 0.02 parts tetramethylethylenediamine. The mixture is stirred in an ice bath at 8°C for 12 hours, transferred to a beaker, and dried at 70°C for 8 hours to obtain the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. The lithium diatomite was purchased from Rockwood's LAPONITE XLG, with the molecular formula [missing information]. The diameter is 20-30nm, the thickness is 1nm, the weight average molecular weight of polyacrylic acid is 250,000, and it is purchased from Sigma-Aldrich. N-isopropylacrylamide, potassium persulfate and tetramethylethylenediamine are purchased from Aladdin.

[0072] This embodiment also provides a method for preparing the above-mentioned environmentally friendly rolling fluid, the preparation method comprising: According to the formulation, EO-PO block polyether, neodecanoic acid, isononanoic acid, triethanolamine, lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, benzotriazole, 2,6-di-tert-butyl-p-cresol, Clariant Dispersogen PLF 100 and water are mixed to obtain an environmentally friendly rolling solution.

[0073] Example 4 This embodiment provides an environmentally friendly rolling fluid, which differs from that of Example 1 only in that the weight-average molecular weight of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is 4000.

[0074] In this embodiment, the preparation method of the above-mentioned lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is as follows: 7.5 parts of lithium diatomite, 0.3 parts of polyacrylic acid, and 20 parts of water are mixed in a three-necked flask and stirred under a nitrogen atmosphere. Then, 7.5 parts of N-isopropylacrylamide monomer, 0.04 parts of N,N'-methylenebisacrylamide, 0.5 parts of potassium persulfate, and 0.05 parts of tetramethylethylenediamine are added. The mixture is stirred at 2°C in an ice bath for 8 hours, transferred to a beaker, and dried at 60°C for 40 hours to obtain the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. The lithium diatomite was purchased from Rockwood's LAPONITEXLG, with the molecular formula [missing information]. The diameter is 20-30 nm, the thickness is 1 nm, the weight average molecular weight of polyacrylic acid is 5000, and it is purchased from Sigma-Aldrich. N-isopropylacrylamide, potassium persulfate and tetramethylethylenediamine are purchased from Aladdin.

[0075] Example 5 This embodiment provides an environmentally friendly rolling fluid, which differs from that of Example 1 only in that the weight-average molecular weight of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is 20,000.

[0076] In this embodiment, the preparation method of the above-mentioned lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is as follows: 7.5 parts of lithium diatomite, 0.5 parts of polyacrylic acid, and 20 parts of water are mixed in a three-necked flask and stirred under a nitrogen atmosphere. Then, 15 parts of N-isopropylacrylamide monomer, 0.02 parts of N,N'-methylenebisacrylamide, 0.3 parts of potassium persulfate, and 0.02 parts of tetramethylethylenediamine are added. The mixture is stirred at 2°C in an ice bath for 8 hours, transferred to a beaker, and dried at 60°C for 40 hours to obtain the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. The lithium diatomite was purchased from Rockwood's LAPONITEXLG, with the molecular formula [missing information]. The diameter is 20-30nm, the thickness is 1nm, the weight average molecular weight of polyacrylic acid is 100,000, and it is purchased from Sigma-Aldrich. N-isopropylacrylamide, potassium persulfate and tetramethylethylenediamine are purchased from Aladdin.

[0077] Example 6 This embodiment provides an environmentally friendly rolling fluid, which differs from that of Example 1 only in that the critical dissolution temperature of the aqueous solution of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material with a mass concentration of 1% is 35°C.

[0078] In this embodiment, the preparation method of the above-mentioned lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is as follows: 7.5 parts of lithium diatomite, 0.3 parts of polyacrylic acid, and 20 parts of water are mixed in a three-necked flask and stirred under a nitrogen atmosphere. Then, 30 parts of N-isopropylacrylamide monomer, 0.02 parts of N,N'-methylenebisacrylamide, 0.3 parts of potassium persulfate, and 0.02 parts of tetramethylethylenediamine are added. The mixture is stirred at 2°C in an ice bath for 8 hours, transferred to a beaker, and dried at 60°C for 40 hours to obtain the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. The lithium diatomite was purchased from Rockwood's LAPONITEXLG, with the molecular formula [missing information]. The diameter is 20-30 nm, the thickness is 1 nm, the weight average molecular weight of polyacrylic acid is 5000, and it is purchased from Sigma-Aldrich. N-isopropylacrylamide, potassium persulfate and tetramethylethylenediamine are purchased from Aladdin.

[0079] Comparative Example 1 This comparative example provides a rolling fluid that differs from that of Example 1 only in that EO-PO block polyether is not added, and the proportion of EO-PO block polyether is distributed to the other components according to the original formulation.

[0080] Comparative Example 2 This comparative example provides a rolling fluid that differs from that of Example 1 only in that it does not contain the lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, and the proportion of the lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is distributed to the other components according to the original ratio.

[0081] Comparative Example 3 This comparative example provides a rolling fluid that differs from that of Example 1 only in that the mass ratio remains the same, and the lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is replaced with a commonly used water-soluble extreme pressure additive EO segment modified phosphate ester (purchased from EVONIK, REWOCOROS AL 200:1000:200:OI:P).

[0082] Performance testing: Performance tests were conducted on the above embodiments and comparative examples, and the results are shown in Table 1.

[0083] (1) Lubrication performance test: Evaluation of film thickness measuring instrument (PCS Interferometer): The film-forming ability of the rolling fluid between friction pairs was evaluated, with oil film thickness (nm) as the scale. The test method was as follows: a diluted rolling fluid sample (diluted with water as solvent, with a mass concentration of 5%) was placed in the test chamber. Under certain conditions (60℃, load 50N), the test ball and the test disk moved relative to each other, with the speed gradually increasing (0-6m / s). A total of 68 data points were measured, and the average film thickness was recorded as the average film thickness, which was the average of the 10th to 30th data points (the data effect was relatively stable within this range).

[0084] Evaluation of Reciprocating Friction and Wear Testing Machine (RCP): The test method is as follows: 0.5 μL of diluted rolling slurry sample (diluted with water as solvent, the mass concentration of rolling slurry is 5%) is loaded onto the test ball. Under the set conditions (150℃, load 2.5 kg), the test ball is made to reciprocate on the aluminum plate. One reciprocation is recorded as one cycle, and a total of 40 cycles are performed. Then, the average friction coefficient of the 2nd to 5th cycles is recorded as the average friction coefficient.

[0085] (2) Water corrosion test: Corrosion area evaluation: The testing method was as follows: For each sample test, two 8cm × 16cm 3003 aluminum plates were used. Before the test, both sides of the aluminum plates were wiped with isopropyl alcohol (IPA) and dried with compressed air. Then, 1mL of diluted rolling slurry sample (diluted with water as the solvent, with a mass concentration of 5%) was dropped onto one of the aluminum plates, and the other aluminum plate was then placed on top until completely overlapped. Afterward, the plates were wrapped with plastic wrap and placed in a 60℃ oven for 72 hours. After opening the oven, the percentage of rusted area was evaluated.

[0086] (3) Antibacterial performance test: Evaluation of biological challenge experiments: The testing method is as follows: In a microbiology laboratory, a biological challenge experiment is conducted. Fresh bacterial strains are added each week and cultured on a shaker (60℃, 100 rpm). After 48 hours, the bacterial / fungal content is measured. If the total bacterial count is >10, the test is considered successful. 6 If the condition is not met, it is considered terminated, with the duration (number of weeks) of adherence as the metric.

[0087] Table 1 The following points can be observed from the data in Table 1: (1) As can be seen from the data of Examples 1-3, the rolling fluid provided by the present invention, under better conditions, can achieve an average film thickness of more than 143 nm, an average friction coefficient of less than 0.1, a corrosion area of ​​less than 10% in the water corrosion test, and a duration of more than 6 weeks in the antibacterial performance test.

[0088] (2) As can be seen from the data in Examples 1 and 4-5, the present invention can further improve the lubrication performance, water corrosion resistance, and antibacterial performance by optimally controlling the weight-average molecular weight of the lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. It should be noted that in Example 6, due to the excessively low critical dissolution temperature of the nanocomposite material, the polymer (i.e., the nanocomposite material) precipitated at the working temperature, resulting in a turbid liquid, which was deemed unqualified as a product and had no testing value. Therefore, the present invention, by optimally controlling the range of the critical dissolution temperature, can ensure that the rolling fluid remains stable at the working site, meeting the industry's performance requirements for the rolling fluid.

[0089] (3) As can be seen from the data of Example 1 and Comparative Examples 1-3, the present invention, by specifically using EO-PO block polyether and lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite materials, has excellent lubrication performance, water corrosion resistance and antibacterial performance compared with existing water-soluble extreme pressure additives.

[0090] In summary, the environmentally friendly rolling fluid provided by this invention utilizes the synergistic effect of water-soluble polyether and lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite materials to replace traditional lubricating base oils. It can achieve good cooling performance, lubrication performance, and rust prevention performance in a water-based system, is easy to clean, resists impurities and bacteria, and is environmentally friendly.

[0091] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An environmentally friendly rolling fluid, characterized in that, The environmentally friendly rolling fluid comprises the following components by mass percentage: 10-90% water-soluble polyether, 0.1-5% organic amine soap, 2-10% lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, 0.1-2% metal deactivator, 0.1-2% antioxidant, 0.1-2% wetting agent, and the balance being water.

2. The environmentally friendly rolling fluid according to claim 1, characterized in that, The water-soluble polyether includes EO-PO block polyether; Preferably, the weight-average molecular weight of the EO-PO block polyether is 2000-10000.

3. The environmentally friendly rolling fluid according to claim 1 or 2, characterized in that, The organic amine soap is prepared using organic acids and organic amines; Preferably, the organic acid includes a monobasic acid and / or a dibasic acid; Preferably, the monocarboxylic acid includes any one or a combination of at least two of the following: nonanoic acid, isononanoic acid, octanoic acid, heptanoic acid, n-decanoic acid, neodecanoic acid, lauric acid, coconut oil acid, palmitic acid, or stearic acid; Preferably, the dicarboxylic acid includes any one or a combination of at least two of sebacic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, or octadecanoic acid; Preferably, the organic amine includes an alcohol amine containing a hydroxyl group; Preferably, the organic amine includes any one or a combination of at least two of monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, or triisopropanolamine; Preferably, the molar ratio of the carboxyl group in the organic acid to the amino group in the organic amine is 1:(1-1.6).

4. The environmentally friendly rolling fluid according to any one of claims 1-3, characterized in that, The lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material uses lithium diatomite including XLG type lithium diatomite; Preferably, the molecular formula of the lithium diatomite is: ; Preferably, the lithium diatomite comprises nanoscale flaky lithium diatomite; Preferably, the diameter of the lithium diatomite is 20-30 nm; Preferably, the thickness of the lithium diatomite is 0.8-1.2 nm.

5. The environmentally friendly rolling fluid according to any one of claims 1-4, characterized in that, The lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material uses polyacrylic acid with a weight-average molecular weight of 5,000-250,000.

6. The environmentally friendly rolling fluid according to any one of claims 1-5, characterized in that, The preparation method of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material includes the following steps: Lithium diatomite, polyacrylic acid and water were mixed, and then N-isopropylacrylamide monomer, crosslinking agent, initiator and auxiliaries were added. The mixture was reacted and dried in sequence to obtain lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material. Preferably, the raw materials for preparing the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, by weight, include 5-10 parts lithium diatomite, 0.1-0.5 parts polyacrylic acid, 10-20 parts N-isopropylacrylamide monomer, 0.02-0.03 parts crosslinking agent, 0.3-0.5 parts initiator, 0.02-0.04 parts additives, and 15-25 parts water; Preferably, the crosslinking agent comprises N,N'-methylenebisacrylamide; Preferably, the initiator comprises potassium persulfate; Preferably, the adjuvant comprises tetramethylethylenediamine; Preferably, the mixing and reaction are both carried out under a nitrogen atmosphere; Preferably, the reaction temperature is 0-8°C; Preferably, stirring is performed during the reaction; Preferably, the reaction time is 4-12 hours; Preferably, the drying temperature is 40-80℃; Preferably, the drying time is 8-72 hours.

7. The environmentally friendly rolling fluid according to any one of claims 1-6, characterized in that, The weight-average molecular weight of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material is 5000-15000. Preferably, the critical dissolution temperature of the aqueous solution of the lithium diatomite / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material with a mass concentration of 1% is ≥50℃.

8. The environmentally friendly rolling fluid according to any one of claims 1-7, characterized in that, The metal deactivators include benzotriazoles; Preferably, the antioxidant comprises 2,6-di-tert-butyl-p-cresol.

9. A method for preparing an environmentally friendly rolling fluid as described in any one of claims 1-8, characterized in that, The preparation method includes: An environmentally friendly rolling solution is obtained by mixing water-soluble polyether, organic acid, organic amine, lithium diatomaceous earth / polyacrylic acid / polyN-isopropylacrylamide nanocomposite material, metal deactivator, antioxidant, wetting agent and water.

10. An application of the environmentally friendly rolling fluid as described in any one of claims 1-8, characterized in that, The environmentally friendly rolling fluid is used for hot rolling of aluminum or aluminum alloys.

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