JPS6313768B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for supplying emulsion rolling fluid in metal rolling operations. Conventionally, in metal rolling operations, the contact area between the work roll and the rolled material is sprayed with an oil agent made by dispersing lubricating oil such as mineral oil, fat, or a mixture of these oils in water to form an oil-in-water emulsion, that is, an O/W emulsion. It was being sprayed with oil to refuel. At this time, the oil particles of the emulsion adhere to the rolls and the metal surfaces of the rolled material and perform a lubricating action, while the aqueous phase of the emulsion performs a cooling action to remove frictional heat, and collectively exhibits the effect of a rolling oil. Here, a good rolling oil needs to be one in which the oil particles of the emulsion are easily separated and easily adhere to metal surfaces to form an effective lubricating film. On the other hand, at metal rolling work sites, a large-capacity rolling oil storage tank with a capacity of several tens of kilograms is installed to store rolling oil emulsion, and while precisely controlling the emulsion concentration to the appropriate level, the oil is circulated through piping to the lubricated parts of the rolling mill. . Here, as a good rolling oil agent, it is necessary that it has good stability, does not separate oil particles in the emulsion, and is easy to control the concentration. In other words, a good emulsion rolling oil is an emulsion that is stable in the storage tank but unstable in the spray nozzle. However, such properties cannot be obtained with ordinary O/W emulsions. In recent years, various studies have been conducted to examine the composition and phase structure of emulsions and to obtain such properties. For example, by adjusting the type and amount of surfactant,
There is an example of an O/W emulsion in a somewhat unstable state. However, this did not satisfy the stability in the storage tank. It has also been proposed to prepare a water-in-oil emulsion in which water is dispersed in oil, that is, a W/O emulsion, and then supply a dispersion in which the emulsion is mechanically unstablely dispersed in water. In this case as well, the W/O emulsion is difficult to disperse in water and often adheres to metal surfaces, but it is unstable in the storage tank and immediately separates into two phases, the W/O emulsion and water, if it is allowed to stand still. Ta. Furthermore, a method of supplying a composite emulsion designated as W/O/W emulsion was also proposed. This is a W/O emulsion that is further stably dispersed in water using a surfactant, and has a composite structure in which oil particles are suspended in water and water particles are further present within the oil particles. Also referred to as water emulsion. It has been recognized that this W/O/W emulsion is produced when a specific surfactant is added to the base oil, and a stable emulsion can be easily obtained by diluting the stock solution composition in water. It was also explained that the oil adhesion to the surface was excellent. However, this property is similar to O/W emulsion, and W/O emulsion depends on the type and amount of surfactant used as an aqueous dispersant for W/O emulsion.
O emulsions with good or poor dispersion stability in water can be produced. All of the W/O/W emulsions with the compositions proposed to date have such good stability that they are suitable for use in storage tanks. In this case, the adhesion of oil particles (containing water particles) is poor and the objective cannot be achieved. The present inventors studied these prior art in detail and attempted to make fundamental improvements. Considering the phase structure of a W/O/W emulsion, as described above, it has a structure in which oil particles are suspended in water and water particles are further present in the oil particles. In such a structure, there are two types of interfaces between the water phase and the oil phase: a W/O interface in the inner phase and an O/W interface in the outer phase. In order to stabilize the W/O interface, a lipophilic surfactant is added to lower the interfacial energy on the oil side of the W/O interface. Furthermore, in order to stabilize the O/W interface, a hydrophilic surfactant is added to lower the interfacial energy on the water side of the O/W interface. To make a W/O/W emulsion, these two types of surfactants with appropriate properties can be used in an appropriate ratio, but in conventional emulsions, the ratio of lipophilic surfactants used is relatively small; It was observed that the proportion of hydrophilic surfactants used was relatively high, and that the oil solubility of lipophilic surfactants was slightly tilted towards hydrophilicity, resulting in the O/W interface becoming too stable and the internal phase oil particles It is presumed that it was difficult to separate and had poor adhesion to metal surfaces. In an attempt to enhance the adhesion of W/O/W emulsions without impairing their stability, the present inventors developed lipophilic properties with the aim of stabilizing the W/O interface and reducing the stability of the O/W interface. We have selected a surfactant with strong oil solubility, increased its usage ratio significantly more than before, and conducted research by comparing and examining its properties. However, in the process of this research, we inadvertently used a specific lipophilic surfactant and a specific hydrophilic surfactant, and also changed the ratio of these two types of surfactants to a specific ratio by increasing the ratio of the former. If the amount of lipophilic surfactant is sufficient to stabilize the W/O interface, and the amount of hydrophilic surfactant is slightly insufficient to stabilize the O/W interface, then external By applying impact such as rapid stirring, the oil particles in the W/O/W emulsion are once dispersed and then aggregated, the O/W interface is broken, and the internal W/O phase is continuous, forming a W/O emulsion. We have obtained new knowledge that adhesion to metal surfaces is significantly improved. Furthermore, if the phase is inverted to form a W/O emulsion and left to stand still, the aqueous phase will separate and the W/O emulsion will overlap on top of it to form two layers. We also obtained the knowledge that it can be dispersed in various shapes and distributed in circulation. I think about these reasons as follows. In the present invention, since a slightly insufficient amount of hydrophilic surfactant is added, slightly larger emulsion particles formed by gentle stirring can be stably dispersed.
The amount of fine particles caused by vigorous stirring is insufficient for stable dispersion. If the mixture is vigorously stirred, it will first be finely dispersed and then aggregated to form a stable W/O phase, and if it is gently stirred, it will return to W/O. These phenomena occur only in compositions created by mixing the above-mentioned specific surfactants found by the present inventors in specific ratios; The inventors were also able to find out that this does not occur with W emulsion. The present invention is based on these findings, and is a metal rolling fluid supply method for supplying a specific W/O/W emulsion having such properties as a rolling fluid in a metal rolling operation. At a metal rolling work site, a specified amount of a rolling oil stock solution with such properties is added to a storage tank filled with a specified amount of water and dispersed by gentle stirring, or even if it is stirred somewhat vigorously, it gradually settles down after being dispersed. If you let the water sit for a while and then gently stir it, a W/O/W composite emulsion will be generated and can be stored stably. If you spray it through the supply piping with vigorous stirring or other impact from the spray nozzle, the W/O emulsion phase and water will be separated. When the phases coexist, when this is sprayed onto rolls and workpieces, the W/O emulsion easily adheres to the metal surface and forms an effective lubricating film, and when the liquid is returned to the storage tank and is gently stirred, it becomes stable. It can be returned to W/O/W and recirculated. Thus, the method of the present invention can be said to be an extremely suitable method for supplying rolling oil. An example of a composition prepared by mixing a specific surfactant in a specific ratio to be used in the metal rolling oil supply method of the present invention is the following composition. Base oil 50-98% by weight, hydroxyl group content (average number of hydroxyl groups in 1 molecule x 17/average molecular weight) 1.5-6.0% by weight
An oil-soluble compound containing 1 to 49% by weight of an oil-soluble compound having an HLB of 10 or more, 0.1 to 16% by weight of a hydrophilic surfactant with an HLB of 10 or more as an essential component, and having a hydroxyl group content of 1.5 to 6.0% by weight, and a hydrophilic compound having an HLB of 10 or more. Compositions having a ratio of 3:1 to 20:1 with surfactant are suitable for the purpose of the present invention. In addition,
HLB is a numerical value that indicates the balance between hydrophilicity and lipophilicity of a surfactant, and is calculated using the following formula. This value ranges from a minimum of 0 to a maximum of 20, and the higher the value, the greater the hydrophilicity. HLB=20 (MH/M) MH: Molecular weight of the hydrophilic group M: Molecular weight of the activator The base oils used here include animal fats such as beef tallow and lard, vegetable oils such as palm oil and rapeseed oil, and machine oil It is one or a mixture of two or more synthetic oils such as mineral oil, ester oil, and synthetic hydrocarbons, and may also be used in combination with waxes, tar pitch, etc. Examples of oil-soluble compounds having a hydroxyl group content of 1.5 to 6.0% by weight include partial esters of sorbitan such as sorbitan trilaurate, sorbitan dioleate, and sorbitan trioleate; partial esters of glycerin such as glycerin dilaurate and glycerin dioleate; Methylpentane, 1,3,5
-Partial esters of polyhydric alcohols and carboxylic acids such as triolditaloate, monoethers of polyalkylene glycols such as polypropylene glycol monostearyl ether, polypropylene glycol monononyl phenyl ether, cholesterol, lecithin, castor oil, polyesters of castor oil Castor oil derivatives such as oxypropylene adducts, polyalkylene glycol derivatives of amines such as lanolin and polyoxypropylene oleylamine, polyalkylene glycol derivatives of amides such as polyoxypropylene stearylamide, and polymers such as polybutadiene with hydroxyl groups introduced into the molecule. and oligomers, partially complex esters of polyhydric alcohols, dibasic acids, and fatty acids, etc., which have hydroxyl groups in the molecule, and the hydroxyl group content is 1.5 to 6.0% by weight,
and is a compound that can be dissolved in base oil. Although castor oil is not soluble in mineral oil, it can be used in base oils that can dissolve it, such as animal and vegetable oils and ester oils. These are compounds that belong to the range of lipophilic surfactants, but they are far more lipophilic than what was conventionally thought of as lipophilic surfactants for W/O/W use, and are active agents that have hydroxyl groups. is an important point. Only compounds within this range are suitable for the purposes of this invention. The hydroxyl group content is determined by measuring the hydroxyl group content using a method for quantifying hydroxyl groups such as acetylation method (urethanization method) or dehydration method, and calculates the average number of hydroxyl groups in one molecule x
17/expressed as average molecular weight. Sorbitan monooleate and coconut oil fatty acid diethanolamide, which have been conventionally proposed as lipophilic surfactants for W/O/W, cannot be used because their hydroxyl values are too large. Furthermore, cyclohexylamide of oleic acid and dicyclohexylamide of coconut oil fatty acid have strong lipophilic properties but do not have hydroxyl groups and cannot be used. As a hydrophilic surfactant with HLB10 or higher,
Nonionic surfactants with an HLB of 10 or more can be used, and among them, nonionic surfactants with an HLB of 11 to 15 can be used preferably. For example, polyoxyethylene sorbitan monooleate (HLB15.0), polyoxyethylene sorbitan trioleate (HLB11), polyoxyethylene stearyl ether (HLB13.9), etc. are preferred. This hydrophilic surfactant is hydrophilic and O/
It is necessary to have W emulsifying properties, and those with strong lipophilicity with an HLB of less than 10 cannot be used. The blending ratio of these three components is 50-98% by weight of the base oil, 1-49% by weight of an oil-soluble compound having a hydroxyl group content of 1.5-6.0% by weight, and 0.1-16% by weight of a hydrophilic surfactant with HLB of 10 or higher. It is necessary that the ratio of the oil-soluble compound containing 1.5 to 6.0% by weight of hydroxyl groups and the hydrophilic surfactant having an HLB of 10 or more is 3:1 to 20:1. If the hydroxyl group content is less than 1.5% by weight, it is insufficient to form a W/O emulsion in the internal phase, and if it is more than 6.0% by weight, the hydrophilicity is too large and the stabilization of the W/O interface becomes insufficient, and the W/O/W It is weak against shocks such as rapid external stirring applied to the emulsion and easily breaks, thus failing to achieve its purpose. In addition, when the oil-soluble compound having a hydroxyl group content of 1.5 to 6.0% by weight is less than 1% by weight, the internal phase W/
Insufficient to form O emulsion, 49% by weight
When the amount is larger than that, the stability of the W/O emulsion is too good and the formation of the W/O/W emulsion becomes insufficient. O/W if HLB of hydrophilic surfactant is 10 or less
The emulsifying property is insufficient and the amount added is 0.1% by weight.
Similarly, the O/W emulsifying property is insufficient in the case of less than 16% by weight, and the stability of the O/W interface is too good at 16% by weight or more.
Even if the O/W emulsion is subjected to shocks such as rapid stirring from the outside, the O/W interface film will not break and the W/W emulsion will not break.
No phase inversion to O emulsion occurs. If the ratio of an oil-soluble compound having a hydroxyl group content of 1.5 to 6.0% by weight and a hydrophilic surfactant of HLB10 or higher is less than 3:1, the stability of the W/O interface will be weak and it will resist shocks such as rapid stirring. The O interface film is easily broken and the W/O/W emulsion undergoes phase inversion to become an O/W emulsion. At 20:1 or more, the stability of the O/W interface is weak and W/O/
The phase inversion of W emulsion to W/O emulsion becomes easier. That is, by adding the stock solution of the composition of the present invention, which is the object of the present invention, into water in a storage tank and gently stirring to disperse it, W /O/W emulsion is generated and can be stored stably, and if a shock such as sudden stirring is applied when injecting it through piping with a spray nozzle, the phase will change and a W/O emulsion will be generated, unlike conventional O/W. Emulsion and general W/
It has much better adhesion than O/W emulsion, provides a good lubricating film when sprayed onto rolls and metal surfaces of workpieces, and cools the water separated during W/O emulsion phase inversion. This provides a method for supplying metal rolling fluid that achieves the intended purpose in combination with the properties of oil and fluid, and that also enables circulating supply of W/O/W in a storage tank. In addition to the three components, additives such as a rust preventive agent, an oiliness improver, and an extreme pressure additive may be added to the composition of the present invention as required. The present invention can be applied to all metal rolling operations using the circulating oil supply method, and is applicable to all types of metal rolling operations.
It doesn't matter what the roll material is or the temperature of the metal material. In other words, it can be applied to both cold and hot rolling of ferrous metals and non-ferrous metals. This will be explained in detail below using Examples. Table 1 and Figure 1 show Examples 1 to 5 and Comparative Example 1.
The components, changes in the emulsion state during feeding, and rolling performance for each of Examples 1 to 7 are shown below.
That is, the components are shown in Table 1 as weight percent of the composition of the stock solution in each example, and the emulsion state is the state of the 5% emulsion in each example in the storage tank and the state after it is sprayed from the spray nozzle through the supply piping. The results were observed under a microscope and indicated in Table 1 using the emulsion type symbol, and the stability was indicated using the symbols 〇 stable, x separation. For reference, micrographs of the emulsion in the storage tank and after passing through the spray nozzle of Example 1 are shown in FIGS. 1 and 2. In addition, for rolling performance, the amount of oil adhering to the metal (mild steel plate) surface is shown in Table 1 for each 5% emulsion, and the relationship between the load and rolling reduction rate during rolling in a small rolling mill is shown in Table 1. The rolling properties are shown in the figure. The adhesion and rolling properties were combined and shown as rolling performance. The test methods for adhesion and rollability are as follows. (1) Adhesion test method After washing a mild steel plate (SPCC-SD50 x 100 x 0.8 mm) with petroleum benzene and warm methanol, an emulsion (concentration 5% by weight, temperature 50°C) was applied under the following conditions, and after removing moisture. The amount of adhering oil was determined. Test conditions Injection nozzle: Orifice diameter 1.0mm Full cone nozzle Pressure: 5.0Kg/cm ² Time: 3sec Distance between nozzle and mild steel plate: 10cm (2) Rollability test method Rolling was performed using a small rolling mill with the following specifications. Evaluation was made based on the relationship between load and rolling reduction. Rolling mill specifications and test conditions Rolling mill specifications: Work roll 150φ
-SB) 0.5 x 50 x 150 mm) Work roll temperature used after petroleum benzine cleaning: 42 ± 1°C Emulsion concentration: 5% by weight Emulsion temperature: 50°C Emulsion lubrication method: Nozzles (orifice diameter Lubricating at 1.0mm, pressure 5Kg/ ^cm2 ) [Table]

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between rolling load and rolling reduction ratio in small rolling mills of Examples and Comparative Examples. FIG. 2 is a micrograph of the emulsion of Example 1, with 1 showing the state inside the storage tank and 2 showing the state after passing through the spray nozzle.

Claims (1)

[Claims] 1. In metal rolling operations, base oil 50 to 98% by weight hydroxyl group content (average number of hydroxyl groups in one molecule x 17/
Contains as an essential component an oil-soluble compound having an average molecular weight of 1.5-6.0% by weight, 1-49% by weight, a hydrophilic surfactant with HLB10 or higher, 0.1-16% by weight, and a hydroxyl group content of 1.5-49% by weight.
The ratio of oil-soluble compound having 6.0% by weight and hydrophilic surfactant of HLB10 or more is 3:1 to 20:
1 is stored as a W/O/W composite emulsion in a storage tank, phase inverted with a spray nozzle in the supply pipe, and sprayed onto rolls and workpieces as a W/O emulsion. And when it returns to the storage tank, it returns to the W/O/W composite emulsion state again,
A metal rolling oil supply method characterized by circulating supply.