JPS6341594A - Cold rolling oil for steel plate - Google Patents

Abstract

PURPOSE:To provide the titled oil outstanding in coefficient of friction and pressure resistance under high pressure and high-speed revolution, also excellent in mill clearness in steel plate annealing following its rolling, containing a specific esterified product from sorbitol and methyl-branched fatty acid. CONSTITUTION:The objective cold rolling oil containing an esterified product having two or more ester groups prepared by reaction between (A) sorbitol and (B) (i) >=12C (pref. <=28C) methyl-branched fatty acid (optimally, isostearic acid) or, if needed, (ii) a mixed fatty acid comprising the component (i) and <=50mol% of >=12C straight-chain fatty acid.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a highly lubricating rolling oil that has excellent friction coefficient and pressure resistance under high pressure and high speed rotation. without going through any other cleaning process.
No stains will be generated on the surface even if annealed as is. That is, the present invention relates to a cold rolling oil for steel sheets that has excellent mill cleanliness.

(Prior art) The cold rolling oil used when cold rolling thin steel sheets is based on animal or vegetable oils (beef tallow, lard, palm oil, coconut oil, etc.) and mineral oil as the base oil. It is broadly divided into those that do. In recent years, with the improvement of production efficiency such as energy saving and process saving, high reduction rolling, high speed rolling, and micro-lean rolling are becoming popular. Rolling oils using animal/vegetable oils as base oils can handle high loads,
Although it is suitable for high-speed rolling, if a cold-rolled steel plate is annealed without removing the oil adhering to it, the surface of the steel plate will become contaminated in the annealing process. In other words, oils and fats having a triglyceride structure have excellent lubricity, but are unsuitable for mill clean properties (direct annealing properties).

On the other hand, when rolling oil based on mineral oil is used for cold rolling of steel sheets, no surface stains occur even when cold thin steel sheets are directly annealed, and the mill cleanliness is excellent. Poor high reduction rate rolling and high speed rolling properties.

In general, rolling oil based on mineral oil is made of animal/vegetable fats and oils, fatty acids (capric acid, lauric acid, myristic acid, stearic acid, oleic acid, phosphoric acid, etc.) or oil chemistry '7311 to improve rolling lubricity. Monthly issue, P, 695~
Synthetic esters (monoesters, diesters, polyol esters, etc.) such as those listed in 706 are used by adding two agents, but the amount of these additives maintains milk cleanliness. It has been adjusted to the minimum necessary narrow range. As mentioned above, various studies have been conducted on cold rolling oils that simultaneously satisfy high lubricity and mill cleanliness.
5600, JP-A-59-804'98) At present, sufficient performance has not been achieved.

(Problems to be Solved by the Invention) The present invention is a cold rolling oil for thin steel sheets that contributes to improving production efficiency such as energy saving and process saving. It is stable and stable against chemical reactions such as oxidation, decomposition, and polymerization. Furthermore, the present invention provides a cold rolling oil for steel sheets that generates little thermal decomposition residual salt in the rolling oil during an annealing process, is easily volatilized, and has both steel sheet surface cleanliness and high lubricity.

(Means and effects for solving the problem) The present invention is a cold rolling oil for steel that is mainly composed of a synthetic ester of sorbitol and a methyl branched fatty acid having 12 or more carbon atoms, and has high lubricity and high mill cleanliness. This makes it possible to effectively roll a thin steel plate and annealing the steel plate without degreasing the steel plate.

The synthetic ester referred to in the present invention is an ester compound that has been molecularly designed and synthesized for this purpose.

In recent years, synthetic esters have been used as rolling oil additives or as base oils, but few of the synthetic esters currently used in cold rolling oils have been synthesized for this purpose, and are used in engine oils and The synthetic ester of the present invention, which is selected from existing synthetic esters used in hydraulic oils or other lubricants, is suitable for cold rolling oils, that is, it has high lubricity and high mill cleanliness. It has the following characteristics and is composed of the following molecular design.

That is, the present invention is a cold rolling oil for steel sheets containing an esterification product of sorbitol and a methyl branched fatty acid having two or more carbon atoms, which has two or more ester groups.

Furthermore, an esterification product of sorbitol and a mixed fatty acid in which 50 mol% or less of the methyl branched fatty acid having 12 or more carbon atoms is replaced with a straight chain fatty acid having 12 or more carbon atoms, which has two or more ester groups. It is a cold rolling oil containing

The methyl branched fatty acids having 12 or more carbon atoms shown here include intoticanoic acid, isotridecanoic acid, isomyristic acid, isopalmitic acid, isostearic acid, inarachic acid, isobhenic acid, isolignoceric acid, isocerotic acid, inmontanic acid, etc. can be used.

When a methyl branched fatty acid having less than 12 carbon atoms is used, the degree of improvement in lubricity during cold rolling of a steel sheet is small. On the other hand, the upper limit of the number of carbon atoms in the methyl branched fatty acid is not particularly limited, but it is preferably 28 or less carbon atoms, which is generally an industrially available range. Examples of methyl branched fatty acids having 12 or more carbon atoms include typical methyl branched fatty acids in lanolin fatty acids, oleic acid, and methyl branched fatty acids obtained as byproducts when producing dimer acid from linoleic acid. These are generally represented by general formula (1).

(However, m+n is an integer of 8 or more) Sorbitol used in the production of the synthetic ester of the present invention undergoes dehydration condensation during the reaction process and changes into sorbitan, sorbite, etc. as shown below. producing a composition;

i engineering Engineering 　　　　　　　　　　　－〇〇1 (“Synthetic Surfactants” published by Ohkyo Publishing, Hirotaka Horiguchi, p.

Sorbitan fatty acid ester, commonly known as 5pan, has been widely used as a nonionic surfactant. The esterified product with saturated fatty acids (lauric acid, stearic acid, etc.) is a waxy solid with a high melting point and is not suitable for use as a rolling oil as in the present invention. Esterification products with unsaturated fatty acids such as oleic acid are liquid at room temperature, but they do not have good stability or direct annealing properties as cold rolling oils. Furthermore, the degree of improvement in lubricity during cold rolling of steel sheets is small.

The present invention converts the esterification product of sorbitol and straight chain fatty acid, which has been widely used as a surfactant, into an esterification product with methyl branched fatty acid, thereby producing a low freezing point, highly stable oil agent for steel sheets. The degree of improvement in lubricity during rolling is clearly high, and direct annealing properties are also improved.
We have discovered performance that was previously unimaginable.

The methyl branched fatty acid suitable for rolling lubrication of the present invention has 1 carbon number.
If the number of carbon atoms is less than 12, the desired rolling lubrication properties will be poor, and it will be difficult to obtain methyl branched fatty acids having less than 12 carbon atoms industrially.

Although there is no particular upper limit to the number of carbon atoms, a carbon number of 28 or less is preferred as an industrially available range.

- It is preferable that the main ingredient is instearic acid, which is an isomerized methyl branched fatty acid having 18 carbon atoms obtained from oleochemical raw materials.

Among saturated branched fatty acids, those with a fatty acid branched at the α-position mainly have relatively long-chain alkyl groups, so although they have good thermal stability and oxidative stability, they are not as good as expected in terms of rolling lubricity. performance cannot be obtained. This is considered to be a difference in performance due to the branched structure of fatty acids.

In the esterification product of the present invention, a diester, triester or tetraester compound having two or more ester groups provides very favorable results for rolling lubrication. On the other hand, when mononystyl is the main component, it exhibits the properties of an emulsifier similar to the monoester of sorbitan and straight chain fatty acids, which are well-known emulsifiers, and this results in disadvantageous results for the rolling lubrication of the steel sheet, which is not desirable. .

Furthermore, an esterified product in which 50 mol% or less of the methyl branched fatty acid is replaced with a straight chain fatty acid having 12 or more carbon atoms also shows good results in rolling performance. In this case, linear fatty acids having less than 12 carbon atoms will only improve the lubricity to a lesser extent when cold rolling a steel sheet. The number of carbon atoms is not particularly limited, but it is generally preferable to have 30 or less carbon atoms as it is industrially available at low cost, such as lauric acid, myristic acid, palmitic acid,
Stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, octacosanoic acid, palmitoleic acid, oleic acid, erucic acid, ricinoleic acid, hydroxystearic acid, linoleic acid, etc. can be used.

During the synthesis, methyl branched aliphatic acids and straight chain fatty acids are mixed in a predetermined ratio.

An esterified product in which more than 50 mol% of the methyl branched fatty acid is substituted with a straight chain fatty acid has a high melting point and is not suitable for use as a rolling oil.

In other words, when cold rolling a steel sheet, the present invention has demonstrated that the lubricity of the esterification product of sorbitol and a methyl branched fatty acid having 12 or more carbon atoms can be improved by using commonly used animal/vegetable fats and oils as well as generally known oils and fats. It is clearly superior to synthetic ester oils, and shows superior performance in terms of bath staining, heat and oxidation stability during actual use, and despite being a saturated fatty acid, The esterified product remains liquid at room temperature and is very convenient for use as rolling oil.

Although it is structurally similar to sorbitan straight chain fatty acid ester, commonly known as 5Pan, which has conventionally been widely used as an emulsifier, the present invention is characterized by using a methyl branched fatty acid as the fatty acid. It is an esterified product having two or more ester groups, which maintains a liquid state at room temperature, has excellent lubricity, and shows favorable results in terms of oxidation stability and annealing property. The purpose of use of what is commonly known as 5pan is only as an emulsifier, and the present invention has chemically designed its molecules to be suitable for cold rolling of steel sheets. 5p
The idea is completely different from an.

When using the synthetic ester of the present invention in rolling oil,
Synthetic esters can also be used alone as rolling oil. In addition, other base oils such as mineral oils, animal and vegetable oils, emulsifiers, fatty acids,
It can also be used in combination with antioxidants, corrosion inhibitors, etc.

When the synthetic ester compound of the present invention is mixed with other base oils, etc., the effect can be seen with addition of 1% by weight or more, but the content should be 5% by weight or more, preferably 20% by weight or more. This stabilizes its properties.

The synthetic ester of the present invention can be synthesized by a conventional method without a catalyst or in the presence of a catalyst, but the synthesis method is not particularly limited.

The following is a description of specific synthesis examples and examples.

Synthesis example 4 equipped with a stirrer, thermometer, nitrogen gas blowing pipe, and water separator
A Tulo flask was charged with 260 g of 70% sorbitol and 1120 g of Emersol 871 isostearate (neutralization value 175, iodine value 10, unsaponifiables 6%), 5 g of sodium hydroxide was added as a catalyst, and xylene was charged as a refluxing solvent. After adding 5% of the amount of water, the mixture was thoroughly stirred and reacted at 160 to 240° C. until the calculated amount of water was distilled out. The required time was 7 hours. After the reaction was completed, xylene was distilled off under reduced pressure, followed by decolorizing filtration using activated clay to obtain a yellowish brown liquid. Yield 1
It was 140 g, and the acid value was 4.7.

(Synthesis Example B) According to the method shown in the above Synthesis Example, an ester compound was synthesized using sorbitol, methyl branched fatty acid, etc. as shown in Table 1.

(Example) Mineral oil used as the base oil of practical rolling oil, palm sleeve,
The lubricity and annealing properties of the rolling oil composition obtained when the synthetic ester of the rolling oil of the present invention is blended with commonly used additives such as emulsifiers, fatty acids, and antioxidants were evaluated.

Emulsion rolling is performed using a two-roll rolling mill, and the rolled material (
spcc) 1, 2 x 20 x 200 mm, the rolling load was measured at a rolling reduction of 40% under conditions of an oil concentration of 3% and a bath temperature of 50°C to evaluate rolling lubricity. As for annealing properties, several tens of steel plates rolled with the sample emulsion liquid were piled up, fixed with narrow steel strips, and annealed in a small annealing furnace.

The heating column during annealing is HNx gas (H2: 5%)12
In an atmosphere of 0mQ/min, the temperature increase rate was set to 10℃/m.
The mixture was heated up to 500°C as an in-crew, kept at 600°C for 1 hour, and then allowed to cool.

Thereafter, a cellophane tape was attached to the surface of the steel plate, and the surface deposits were collected and attached to white paper to visually determine the degree of contamination, and the cleanliness of the steel plate surface was evaluated.

The results are summarized in Table 2.

(Effects of the Invention) The esterification product of sorbitol and a methyl branched fatty acid having 12 or more carbon atoms of the present invention is intended to be used as a rolling lubricant for steel plates, and its molecular design has been designed taking into consideration the necessary conditions for that purpose. However, unlike existing synthetic ester oils that are used as cold rolling oils or as additives, the rolling lubricity of steel sheets has been improved, compared to using conventional animal or vegetable oils. As a result, it is effective in saving energy and resources, such as reducing power costs, and it also has excellent annealing properties, making it possible to omit electrolytic degreasing and reducing equipment costs.

Procedural amendment 19861 lO month λ3rd

Claims (3)

[Claims] (1) Cold rolling oil for steel sheets containing an esterification product of sorbitol and a methyl branched fatty acid having 12 or more carbon atoms, which has two or more ester groups. (2) An esterification product of sorbitol and a mixed fatty acid consisting of 50 mol% or less of a methyl branched fatty acid having 12 or more carbon atoms and a straight chain fatty acid having 12 or more carbon atoms, which has two or more ester groups. cold rolling oil for steel sheets containing (3) Claims (1) or (2) wherein the methyl branched fatty acid having 12 or more carbon atoms is isostearic acid.
Cold rolling oil for steel plates as described in Section 2.