Cold rolling oil composition and cold rolling method

Abstract

The present invention provides a soluble cold rolling oil composition in which oil particles of approximately 0.1 μm or less are dispersed in water, and which has rolling properties (particularly anti-seizure properties) equal to or better than those of water-insoluble rolling oils and emulsion-type rolling oils, while enabling the gloss of products to be made uniform and enabling an improvement in unit consumption compared to emulsion-type rolling oils; and a cold rolling method using the composition. [Solution] A cold rolling oil composition containing (A) a base oil, (B) a specific fatty acid, (C) a specific sulfur-based extreme pressure agent, (D) a specific water-soluble polymer, and (E) a specific amine, and a cold rolling method using the same.

Description

[Technical Field]

[0001] The present invention relates to a soluble cold-rolling oil composition used when cold-rolling metal sheets such as steel sheets, and a cold-rolling method using said composition. [Background technology]

[0002] Known conventional rolling oils include water-insoluble cold rolling oils that are primarily made of refined mineral oils and are used neat, and emulsion-type water-soluble cold rolling oils that are mixed with water to form an emulsion and then supplied. The properties required of these rolling oils include high productivity due to the ability to perform high-speed, high-pressure rolling, no problems with gloss uniformity in the rolled metal sheet, no seizure defects, and reducing the amount of rolling oil used (unit consumption) to reduce costs. Here, in this specification, the unit consumption of rolling oil is defined by the following formula: Rolling oil consumption unit = Rolling oil usage (L) / Rolling volume (tons)

[0003] However, when a water-insoluble cold rolling oil is used, it has good lubrication and a homogeneous phase, resulting in excellent surface gloss, but its cooling ability is insufficient, so that in the case of high-speed, high-pressure rolling, surface seizure defects known as heat scratches occur. Furthermore, since it is a flammable rolling oil composition, there is always a risk of fire due to the generation of processing heat when the processing speed increases.

[0004] Emulsion-type water-soluble cold rolling oils are mainly used as emulsions of a predetermined concentration, which are prepared by appropriately combining one or more base oils such as mineral oils, animal or vegetable oils, synthetic esters, and the like with nonionic surfactants, anionic surfactants, cationic surfactants, rust inhibitors, fatty acids, extreme pressure agents, antioxidants, etc., and diluting the resulting mixture with water.

[0005] This type of emulsion-type water-soluble cold rolling oil is an O / W type in which oil droplets are dispersed in water, forming an emulsion with an average particle size of about 2 to 15 μm, which provides both lubrication and cooling properties. However, the amount of rolling oil used increases, and there is a demand for cost reduction, including the unit consumption of rolling oil. Furthermore, because large oil particles are dispersed in water, the gloss of the product is often insufficient compared to water-insoluble rolling oils, which are a homogeneous phase.

[0006] On the other hand, soluble rolling oils have particle sizes of approximately 0.1 μm or less when diluted with water, which is infinitely smaller than the 2-15 μm particle sizes of emulsion-type oils, making it possible to achieve a uniform gloss on products just like water-insoluble oils. Furthermore, taking advantage of the properties of water-containing oils, they are also effective in cooling.

[0007] Because soluble rolling oil has an extremely small particle size, it does not trap wear particles and other contaminants like emulsion-type rolling oil, and scum, a mixture of oil and the oil, is not formed, reducing oil loss. Furthermore, by using a fine-mesh filter, it is easy to separate the wear particles, and oil is less likely to be trapped in the filter. Furthermore, its excellent cleanability makes it possible to reduce the amount of rolling oil carried away by the steel plate during coil winding, offering the advantage of lowering the unit consumption and reducing costs compared to emulsion-type rolling oil.

[0008] On the other hand, soluble rolling oils are inferior in rolling properties (lubricity and anti-seizure properties) compared to emulsion-type rolling oils, and have been problematic in that they cause seizure on the metal sheet surface, particularly under high-speed, high-pressure rolling conditions. The background to this is that, with the rapid progress in rolling equipment and technology in recent years, rolling speeds have been increased and mass production has been promoted, and the requirements for rolling oils have become increasingly severe, and there is a need for the development of soluble rolling oils that can fully meet these requirements.

[0009] Patent Document 1 discloses a cold-rolling oil composition that can be used as a soluble type, containing an ester of ethylene glycol and a fatty acid, a salt of a fatty acid and an alkali metal and / or an amine, a water-soluble polymer such as poly(oxyethylene-oxypropylene) glycol, and water. However, there is no description of, and sufficient consideration has not been given to, anti-seizure properties during rolling. Furthermore, this cold-rolling oil composition, particularly when used as a soluble type, does not have rolling properties that are equal to or better than emulsion-type cold-rolling oils that are suitable for actual operation, and in particular, its anti-seizure properties are insufficient. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent No. 3481329 Summary of the Invention [Problem to be solved by the invention]

[0011] The object of the present invention is to provide a soluble cold rolling oil composition in which oil particles of approximately 0.1 μm or less are dispersed in water, which has rolling properties (particularly anti-seizure properties) equal to or better than those of water-insoluble rolling oils and emulsion-type rolling oils, while retaining the advantages of conventional soluble rolling oils, namely the dispersion of oil particles of approximately 0.1 μm or less, which enables the gloss of the product to be made uniform and enables an improvement in unit consumption compared to emulsion-type rolling oils, and a cold rolling method using said composition. [Means for solving the problem]

[0012] As a result of intensive research into achieving the above object, the present inventors have found that the above object can be achieved by blending a specific fatty acid, a specific sulfur-based extreme pressure agent, a specific water-soluble polymer, and a specific amine into a base oil. Based on this finding, the present inventors have conducted further studies and have completed the present invention.

[0013] The present invention provides the following soluble cold rolling oil composition and a cold rolling method using said composition.

[0014] 1. (A) a base oil which is at least one selected from the group consisting of refined mineral oils, natural fats and oils, and synthetic esters; (B) at least one fatty acid selected from the group consisting of octylic acid, 2-ethylhexanoic acid, pelargonic acid, isononanoic acid, decanoic acid, isodecanoic acid, neodecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, oleic acid dimer, ricinoleic acid, linoleic acid, linolenic acid, beef tallow fatty acid, coconut oil fatty acid, palm oil fatty acid, tall oil fatty acid, castor oil fatty acid, castor oil fatty acid oligomer, adipic acid, sebacic acid, 5-carboxy-4-hexylcyclohex-2-ene-1-octanoic acid, 6-carboxy-4-hexylcyclohex-2-ene-1-octanoic acid, and dodecanedioic acid; (C) at least one sulfur-based extreme pressure agent selected from the group consisting of sulfurized fats and oils, sulfurized esters, olefin polysulfides, and dialkyl polysulfides; (D) a water-soluble polymer that is a polyalkylene glycol-based polymer having a weight-average molecular weight of 500 to 15,000, and (E) at least one amine selected from the group consisting of monoethanolamine, diglycolamine, monoisopropanolamine, 2-amino-2-methylpropanol, 2-(sec-butylamino)ethanol, diethanolamine, diisopropanolamine, N-methylethanolamine, N-ethylethanolamine, triethanolamine, triisopropanolamine, and cyclohexylamine ethylene oxide adducts; A soluble cold rolling oil composition comprising:

[0015] 2. When the total amount of the base oil (A), fatty acid (B), sulfur-based extreme pressure agent (C), water-soluble polymer (D) and amine (E) is taken as 100% by weight, The blending amount of the base oil (A) is 2 to 50% by weight, The amount of fatty acid (B) is 10 to 50% by weight, The amount of the sulfur-based extreme pressure agent (C) is 6 to 30% by weight, The blending amount of the water-soluble polymer (D) is 2 to 20% by weight, The amount of the amine (E) is 2 to 20% by weight. Item 2. The soluble cold rolling oil composition according to item 1, wherein

[0016] 3. A method for cold rolling a metal sheet, comprising diluting the soluble cold rolling oil composition according to item 1 or 2 above with water and using the diluted oil as a coolant. [Effects of the Invention]

[0017] The soluble cold rolling oil composition and cold rolling method of the present invention provide the following remarkable effects.

[0018] (1) In a soluble cold rolling oil composition containing at least one base oil selected from refined mineral oils, natural fats and oils, and synthetic esters, by blending a specific fatty acid and a specific sulfur-based extreme pressure agent, each in a specific amount, the rolling properties (particularly, seizure resistance) can be improved to the same level as or higher than that of conventional emulsion rolling oils.

[0019] (2) Furthermore, by blending a specific water-soluble polymer, a specific fatty acid, and a specific amine (a fatty acid and an amine react to produce a fatty acid amine salt that is soluble in water), preferably in specific amounts, a soluble oil having an extremely small particle size of about 0.1 μm or less is formed in water, which makes it possible to uniformize the gloss of the product and reduce the unit consumption of rolling oil.

[0020] (3) The soluble cold-rolling oil of the present invention provides a cold-rolling method that can produce high-quality sheets in the cold rolling of metal sheets such as steel sheets, which have good rolling properties (particularly anti-seizure properties) and excellent gloss uniformity after rolling, and can reduce the unit consumption of rolling oil. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram of a two-high rolling mill used to evaluate galling resistance in cold rolling. DETAILED DESCRIPTION OF THE INVENTION

[0022] Soluble cold rolling oil composition The soluble cold rolling oil composition of the present invention comprises: (A) a base oil which is at least one selected from the group consisting of refined mineral oils, natural fats and oils, and synthetic esters; (B) at least one fatty acid selected from the group consisting of octylic acid, 2-ethylhexanoic acid, pelargonic acid, isononanoic acid, decanoic acid, isodecanoic acid, neodecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, oleic acid dimer, ricinoleic acid, linoleic acid, linolenic acid, beef tallow fatty acid, coconut oil fatty acid, palm oil fatty acid, tall oil fatty acid, castor oil fatty acid, castor oil fatty acid oligomer, adipic acid, sebacic acid, 5-carboxy-4-hexylcyclohex-2-ene-1-octanoic acid, 6-carboxy-4-hexylcyclohex-2-ene-1-octanoic acid, and dodecanedioic acid; (C) at least one sulfur-based extreme pressure agent selected from the group consisting of sulfurized fats and oils, sulfurized esters, olefin polysulfides, and dialkyl polysulfides; (D) a water-soluble polymer that is a polyalkylene glycol-based polymer having a weight-average molecular weight of 500 to 15,000, and (E) at least one amine selected from the group consisting of monoethanolamine, diglycolamine, monoisopropanolamine, 2-amino-2-methylpropanol, 2-(sec-butylamino)ethanol, diethanolamine, diisopropanolamine, N-methylethanolamine, N-ethylethanolamine, triethanolamine, triisopropanolamine, and cyclohexylamine ethylene oxide adducts; It is characterized by the combination of the above.

[0023] The soluble cold rolling oil composition of the present invention is prepared by dispersing an oil having an extremely small particle size of about 0.1 μm or less in water to a concentration of about 0.5 to 40% by volume using the soluble cold rolling oil composition as a stock solution, thereby forming a soluble. If the soluble concentration is less than 0.5% by volume, the rolling properties (lubricity and seizure resistance) required for cold rolling of metal strips cannot be obtained, and if it exceeds 40% by volume, excessive lubrication occurs, making slippage more likely to occur.

[0024] base oil Any of the base oils conventionally used in this type of rolling oil composition can be used. Specifically, at least one selected from the group consisting of refined mineral oils, natural oils and fats, and synthetic esters can be used. Examples of refined mineral oils include spindle oil, machine oil, turbine oil, and cylinder oil. Examples of natural oils and fats include whale oil, beef tallow, lard, rapeseed oil, castor oil, rice bran oil, palm oil, and coconut oil. Examples of synthetic esters include monoesters of fatty acids and / or synthetic fatty acids obtained from beef tallow, castor oil, coconut oil, etc. with aliphatic monohydric alcohols having 8 to 18 carbon atoms; and synthetic esters such as di-, tri-, and tetraesters of the above fatty acids and / or synthetic fatty acids with polyhydric alcohols such as ethylene glycol, neopentyl glycol, trimethylolpropane, and pentaerythritol. The base oil may be appropriately selected and used so as to prevent gelation, precipitation, and the like when used in combination with other components.

[0025] The blending amount (addition amount) of base oil (A) is preferably about 2 to 50 wt%, more preferably about 8 to 45 wt%, based on 100 wt% of the total amount of base oil (A), fatty acid (B), sulfur-based extreme pressure agent (C), water-soluble polymer (D), and amine (E). Addition amounts of less than 2 wt% are undesirable from a cost perspective, as rollability (particularly seizure resistance) is insufficient and the amount of relatively inexpensive base oil blended is small. Addition amounts exceeding 50 wt% may result in insufficient amounts of other components, such as fatty acid (B), sulfur-based extreme pressure agent (C), water-soluble polymer (D), and amine (E), resulting in insufficient rollability (particularly seizure resistance) and the formation of solubles. Therefore, it is difficult to achieve both goals.

[0026] Fatty acid (B) The incorporation of fatty acid (B) helps to form a soluble rolling oil with excellent surface quality and unit consumption, and also provides the same or better performance as emulsion-type rolling oils in terms of rolling properties (especially seizure resistance), which are a drawback of the oil. As the fatty acid, for example, at least one fatty acid selected from monocarboxylic acids such as octylic acid, 2-ethylhexanoic acid, pelargonic acid, isononanoic acid, decanoic acid, isodecanoic acid, neodecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid dimer, ricinoleic acid, linoleic acid, linolenic acid, 5-carboxy-4-hexylcyclohex-2-ene-1-octanoic acid, and 6-carboxy-4-hexylcyclohex-2-ene-1-octanoic acid; naturally occurring fatty acids such as beef tallow fatty acid, coconut oil fatty acid, palm oil fatty acid, tall oil fatty acid, castor oil fatty acid, and castor oil fatty acid oligomers (castor oil fatty acid dimer, castor oil fatty acid tetramer, etc.); and dicarboxylic acids such as adipic acid, sebacic acid, dodecanedioic acid, and oleic acid dimer are suitable for use. Preferred examples of the fatty acid include tall oil fatty acid, castor oil fatty acid oligomer (castor oil fatty acid dimer, castor oil fatty acid tetramer), and oleic acid dimer.

[0027] The amount of fatty acid (B) blended (added) is preferably about 10 to 50% by weight, more preferably about 15 to 43% by weight, based on the total amount of base oil (A), fatty acid (B), sulfur-based extreme pressure additive (C), water-soluble polymer (D), and amine (E) taken as 100% by weight. If the amount added is less than 10% by weight, the rollability (especially seizure resistance) becomes insufficient and soluble formation is difficult, making it difficult to satisfy both requirements. Furthermore, even if the amount added exceeds 50% by weight, the effect is not enhanced.

[0028] Sulfur-based extreme pressure agent (C) The incorporation of a sulfur-based extreme pressure agent (C) contributes to improving rolling properties (especially seizure resistance). As the sulfur-based extreme pressure additive, it is appropriate to use at least one sulfur-based extreme pressure additive selected from the group consisting of sulfurized oils and fats, sulfurized esters, olefin polysulfides, and dialkyl polysulfides. As the sulfurized oils and fats, for example, those having a structure in which the double bonds of various oils and fats are crosslinked with sulfur can be used. As the sulfurized ester, for example, dioleic acid methyl polysulfide can be mentioned. As the dialkyl polysulfide, for example, di-t-dodecyl trisulfide can be mentioned.

[0029] The blending amount (addition amount) of the sulfur-based extreme pressure agent (C) is preferably about 6 to 30% by weight, more preferably about 9 to 25% by weight, when the total amount of the base oil (A), fatty acid (B), sulfur-based extreme pressure agent (C), water-soluble polymer (D), and amine (E) is taken as 100% by weight. If the addition amount is less than 6% by weight, the rollability (particularly seizure resistance) becomes insufficient. Furthermore, even if the addition amount exceeds 30% by weight, there is almost no increase in the effect and it is not preferable from the viewpoint of cost.

[0030] Water-soluble polymer (D) The incorporation of the water-soluble polymer (D) contributes to the formation of a soluble dispersion of oil particles with extremely small particle diameters of approximately 0.1 μm or less in water. A polyalkylene glycol polymer is used as the water-soluble polymer. The weight-average molecular weight is preferably approximately 500 to 15,000.

[0031] Examples of polyalkylene glycol polymers include poly(oxyethylene-oxypropylene) glycol, poly(oxyethylene-oxypropylene) glycol monoalkyl ether, and poly(oxyethylene-oxypropylene) glycol glyceryl ether, each of which has a molar ratio of oxyethylene groups to oxypropylene groups in one molecule of about 10 / 90 to 50 / 50.

[0032] The amount of water-soluble polymer (D) added is preferably about 2 to 20% by weight, more preferably about 6 to 17% by weight, based on 100% by weight of the total amount of base oil (A), fatty acid (B), sulfur-based extreme pressure agent (C), water-soluble polymer (D), and amine (E). If the amount added is less than 2% by weight, it becomes difficult to form a soluble rolling oil. Furthermore, even if the amount added exceeds 20% by weight, there is almost no increase in the effect and it is not preferable from the viewpoint of cost.

[0033] Amine (E) The incorporation of amine (E) contributes to the formation of a soluble dispersion of oil particles of extremely small diameters, approximately 0.1 μm or less, in water. Suitable amines include at least one amine selected from alkanolamines such as monoethanolamine, diglycolamine, monoisopropanolamine, 2-amino-2-methylpropanol, 2-(sec-butylamino)ethanol, diethanolamine, diisopropanolamine, N-methylethanolamine, N-ethylethanolamine, triethanolamine, and triisopropanolamine, as well as cyclohexylamine ethylene oxide adducts. Preferred amines include diglycolamine and cyclohexylamine ethylene oxide adducts.

[0034] The blending amount (addition amount) of the amine (E) is preferably about 2 to 20% by weight, more preferably about 4 to 15% by weight, based on 100% by weight of the total amount of the base oil (A), fatty acid (B), sulfur-based extreme pressure agent (C), water-soluble polymer (D), and amine (E). If the addition amount is less than 2% by weight, it becomes difficult to form a soluble rolling oil. Furthermore, even if the addition amount exceeds 20% by weight, there is almost no increase in the effect and it is not preferable from the viewpoint of cost.

[0035] Other ingredients In addition to the base oil (A), fatty acid (B), sulfur-based extreme pressure agent (C), water-soluble polymer (D) and amine (E), various known additives may be added to the rolling oil composition of the present invention, as needed, such as an oiliness improver, a non-sulfur-based extreme pressure agent, an emulsifier, a rust inhibitor, an antioxidant, an antifoaming agent and an antiseptic.

[0036] Examples of oiliness improvers include aliphatic alcohols, etc. Examples of non-sulfur-based extreme pressure agents include tricresyl phosphite and zinc dialkyldithiophosphate.

[0037] Examples of emulsifiers include anionic surfactants such as sodium petroleum sulfonate salts, nonionic surfactants such as polyoxyethylene alkyl ethers, cationic surfactants such as quaternary ammonium salts such as benzalkonium salts, and general polymeric dispersants.

[0038] Examples of rust inhibitors include alkenyl succinic acid and its derivatives, fatty acids such as oleic acid, esters such as sorbitan monooleate, and amines. Examples of antioxidants include phenolic compounds such as 2,6-di-t-butyl-p-cresol and aromatic amines such as phenothiazine. Examples of defoamers include alcohol-based defoamers and silicone-based defoamers. Examples of preservatives include thiazoline-based compounds such as 1,2-benzothiazolin-3-one and pyridine-based compounds such as sodium pyridinethiol-1-oxide.

[0039] coolant The soluble cold rolling oil composition of the present invention is used as a stock solution, and a soluble coolant is prepared by dispersing oil with extremely small particle sizes of approximately 0.1 μm or less in water to a concentration of approximately 0.5 to 40% by volume. If the soluble concentration is less than 0.5% by volume, the rolling properties (lubricity and seizure resistance) required for cold rolling of metal strips cannot be obtained, and if it exceeds 40% by volume, excessive lubrication occurs, making slippage more likely. The water used as dilution water is not particularly limited, and may be, for example, pure water, distilled water, ion-exchanged water, tap water, well water, industrial water, etc.

[0040] Cold rolling method The cold rolling method of the present invention involves rolling a metal sheet using a coolant prepared by dispersing the soluble cold rolling oil composition of the present invention as a stock solution in water. The soluble concentration of the coolant is usually preferably about 0.5 to 40% by volume.

[0041] The soluble cold rolling method of the present invention is preferably a method in which the soluble cold rolling oil composition of the present invention is dispersed in water to form a soluble, and metal sheets such as steel sheets are cold rolled using various rolling mills including reverse rolling mills and tandem rolling mills.

[0042] In the soluble cold rolling method of the present invention, the method of supplying the coolant is not particularly limited. Examples include supplying the coolant from a nozzle using a circulation pump, manual supply using a brush or an oiler, and spray supply. If necessary, the rolling oil composition of the present invention can also be supplied directly. There is also no particular limitation on the material of the rolled workpiece, but the composition is effective mainly as a lubricant for the cold rolling of thin steel sheets. Naturally, it may also be applied to the cold rolling of iron-based materials such as ordinary steel, high-carbon steel, and stainless steel, as well as non-ferrous metals such as aluminum and copper. [Example]

[0043] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to these examples in any way.

[0044] Examples 1 to 12 and Comparative Examples 1 to 4 Cold rolling oil compositions of the present invention and for comparison were prepared using the components shown in Tables 1 and 2. In Tables 1 and 2, the numerical values ​​for each blend composition are all expressed in parts by weight.

[0045] [Table 1]

[0046] [Table 2]

[0047] The specific contents of each component in Tables 1 and 2 are as follows: Base oil (A): Synthetic ester; 2-ethylhexanol palmitate Fatty acids (B): A mixture of tall oil fatty acids and castor oil fatty acids in a 1:1 weight ratio Sulfur-based extreme pressure agent (C): Olefin polysulfide (having 12 carbon atoms and a total sulfur content of 19 to 20% by weight) Water-soluble polymer (D): Poly(oxyethylene-oxypropylene) glycol glyceryl ether (weight average molecular weight = 4550, oxyethylene group / oxypropylene group (molar ratio) = 25 / 75) Amine (E): A mixture of diglycolamine and cyclohexylamine ethylene oxide adduct (2 moles of ethylene oxide adduct) in a 1:1 weight ratio. Antioxidant: 2,6-di-t-butyl-p-cresol

[0048] Next, the water solubility (appearance) and anti-seizure properties were evaluated for each of the cold rolling oil compositions obtained in Examples 1 to 12 and Comparative Examples 1 to 4. The evaluation methods were as follows.

[0049] Solubility (appearance) The solubility in water was evaluated by diluting each of the rolling oil compositions of Examples 1 to 12 and Comparative Examples 1 to 4 with ion-exchanged water to an oil concentration of 10% by volume.

[0050] Evaluation of solubility in water: When a soluble composition was formed in which oil particles of extremely small diameters of about 0.1 μm or less were dispersed in water, the composition was judged as passing the soluble composition and marked with a circle. When an O / W emulsion in which oil droplets were dispersed in water was formed, the composition was judged as failing the emulsion composition and marked with a cross.

[0051] Seizure resistance A rolling test was carried out using a test coil rolling mill and each rolling oil composition to evaluate the seizure resistance. The test conditions were as follows: Rolling mill: A two-high rolling mill as shown in Figure 1 was used. In Figure 1, 1 indicates the first roll, 2 indicates the second roll, 3 indicates the steel strip coil, 4 indicates the steel plate, 5 indicates the tank, 6 indicates the coolant, and 7 indicates the pump. The coolant 6 is supplied to the second roll by the pump 7, and then returned to the tank 5 for circulation. The thick arrow pointing to the left indicates the rolling direction. This two-high rolling mill feeds the steel strip coil of the test piece at 20 m / min, and rotates only the upper second roll at 100 m / min, forcing slippage, which makes it more susceptible to seizure than usual. Roll diameter: φ76mm x 90mm Roll material: SUJ-2 (roll surface: polished with sandpaper #600) First stage roll speed: 20 m / min Second stage upper roll speed: 100 m / min Second stage lower roll speed: 20 m / min Test piece: SPCC-SB (plate thickness 0.4 mm, plate width 20 mm, coil length 5 m) First stage load: 1 ton Second stage set load: 1 ton Test oil (coolant): concentration 2% by volume (diluted with ion-exchanged water), temperature 50°C

[0052] Evaluation of galling resistance: The surface of the steel sheet and the surface of the roll after rolling were observed, and if no galling defects were found, the steel sheet was judged as passing, and marked with a circle. If galling defects were found, the steel sheet was judged as failing, and marked with a cross.

[0053] Tables 3 and 4 below show the evaluation results of the water solubility and anti-seizure properties of each of the cold rolling oil compositions obtained in Examples 1 to 12 and Comparative Examples 1 to 4.

[0054] [Table 3]

[0055] [Table 4]

[0056] As shown in Tables 1 and 2, the rolling oil compositions of Examples 1 to 12 of the present invention contain a synthetic ester base oil, a specific fatty acid, a specific sulfur-based extreme pressure agent, a specific water-soluble polymer, and a specific amine. The blending ratios of these are within the ranges specified in the present invention. Therefore, as shown in Tables 3 and 4, the rolling oil compositions of Examples 1 to 12 of the present invention form soluble oils with extremely small particle sizes of approximately 0.1 μm or less dispersed in water. These compositions excel in anti-seizure properties, which are poorly tolerated by typical soluble oils. The comparative rolling oil composition of Comparative Example 2 also forms soluble oils, but it is clear that it has superior anti-seizure properties compared to the soluble oils. Comparative Example 2 lacks sulfur-based extreme pressure agents, resulting in insufficient anti-seizure properties. Comparative Example 1 lacks fatty acids, Comparative Example 3 lacks water-soluble polymers, and Comparative Example 4 lacks amines, which prevent the formation of soluble oils. However, due to the large particle size of the emulsion and the high content of sulfur-based extreme pressure agents, there are no problems with anti-seizure properties. From the above, it is clear that the rolling oil compositions of the present invention in Examples 1 to 12 form soluble particles in which oil particles having an extremely small diameter of approximately 0.1 μm or less are dispersed in water, and that they have anti-seizure properties equivalent to those of the emulsion-type rolling oils of Comparative Examples 1, 3, and 4. [Industrial Applicability]

[0057] The soluble cold-rolling oil composition of the present invention has rolling properties (particularly anti-seizure properties) equal to or better than emulsion-type rolling oils, and therefore can be applied to high-speed, high-pressure rolling, which is a weakness of conventional soluble oils, and therefore achieves high productivity of rolled products. Furthermore, the soluble cold-rolling oil composition of the present invention has the advantages of dispersing oil with extremely small particles of about 0.1 μm or less in water, which allows for uniform product gloss, and it can improve the unit consumption compared to emulsion-type rolling oils, making it suitable for use in the rolling processing of all materials.

Claims

1. (A) a base oil which is at least one selected from the group consisting of refined mineral oils, natural fats and oils, and synthetic esters; (B) at least one fatty acid selected from the group consisting of octylic acid, 2-ethylhexanoic acid, pelargonic acid, isononanoic acid, decanoic acid, isodecanoic acid, neodecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid dimer, ricinoleic acid, linoleic acid, linolenic acid, beef tallow fatty acid, coconut oil fatty acid, palm oil fatty acid, tall oil fatty acid, castor oil fatty acid, castor oil fatty acid oligomer, adipic acid, sebacic acid, 5-carboxy-4-hexylcyclohex-2-ene-1-octanoic acid, 6-carboxy-4-hexylcyclohex-2-ene-1-octanoic acid, and dodecanedioic acid; (C) at least one sulfur-based extreme pressure agent selected from the group consisting of sulfurized fats and oils, sulfurized esters, olefin polysulfides, and dialkyl polysulfides; (D) a water-soluble polymer that is a polyalkylene glycol-based polymer having a weight-average molecular weight of 500 to 15,000, and (E) at least one amine selected from the group consisting of monoethanolamine, diglycolamine, monoisopropanolamine, 2-amino-2-methylpropanol, 2-(sec-butylamino)ethanol, diethanolamine, diisopropanolamine, N-methylethanolamine, N-ethylethanolamine, triethanolamine, triisopropanolamine, and cyclohexylamine ethylene oxide adduct; A soluble cold rolling oil composition comprising:

2. When the total amount of the base oil (A), the fatty acid (B), the sulfur-based extreme pressure agent (C), the water-soluble polymer (D), and the amine (E) is taken as 100% by weight, The blending amount of the base oil (A) is 2 to 50% by weight, The amount of fatty acid (B) is 10 to 50% by weight, The amount of the sulfur-based extreme pressure additive (C) is 6 to 30% by weight, The blending amount of the water-soluble polymer (D) is 2 to 20% by weight, The amount of the amine (E) is 2 to 20% by weight.

2. The soluble cold rolling oil composition according to claim 1, wherein

3. 3. A method for cold rolling a metal sheet, comprising diluting the soluble cold rolling oil composition according to claim 1 or 2 with water and using the diluted oil as a coolant.

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