KR100711449B1 - Low temperature alkalic detergent composition for removing rolling oil of the strip - Google Patents

Abstract

The present invention relates to a mononuclear cold alkali cleaning agent used for removing the rolled oil of cold rolled steel, 20 to 40 parts by weight of sodium hydroxide, 1 to 5 parts by weight of sodium gluconate, 0.1 to 0.5 parts by weight of potassium hydroxide, poly Provided is a low temperature alkaline detergent composition comprising 0.1 to 1 parts by weight of an oxyethylene-based nonionic surfactant and 1 to 5 parts by weight of an alkyl phenyl ether sulfonate. The alkaline detergent composition of the present invention not only exhibits excellent degreasing and cleaning effects at a low temperature of 50 to 60 ° C., but also easily adjusts concentration as a one-component low temperature alkali cleaner. In addition, it can be applied at low temperatures, saving energy and logistics costs.

Low Temperature Alkaline Cleaners, Sodium Hydroxide, Sodium Gluconate, Potassium Hydroxide, Polyoxyethylene, Alkylphenyl Ether Sulfonates

Description

Low Temperature Alkalic Detergent Composition for Removing Rolling Oil of the Strip}

The present invention relates to a low temperature alkaline detergent composition used for removing cold rolled steel sheet oil, and more particularly to a mononuclear low temperature alkaline detergent composition used for removing rolled oil from cold rolled steel sheet.

In general, in a cold rolling mill, the strip surface is cleaned before the annealing operation to remove the rolling oil and foreign matter from the strip surface in the rolling process. At this time, the surface of the strip is washed by saponification and electrolysis at 80-85 ° C. using sodium hydroxide, potassium hydroxide or sodium silicate as a solvent.

However, the conventional cleaning method causes excessive energy consumption and environmental pollution problems, and in order to solve this problem, a technique of removing rolling oil by adding a degreasing additive to sodium hydroxide at 2 to 4% by weight near 60 ° C (Korea Patent Publication No. 10-0356170 has been published. In the above patent, since the degreasing additive is added to the low concentration sodium hydroxide in a separate degreasing tank at 0.25 to 0.45% by weight, it is difficult to identify the cause and appropriately cope with difficulties in concentration control and operation problems.

It is therefore an object of the present invention to provide a mononuclear alkaline detergent composition for use in removing rolled oil that does not require the addition of additives in the field.

Still another object of the present invention is to provide an alkaline detergent composition which exhibits excellent degreasing performance at low temperatures.

According to the invention,

20 to 40 parts by weight of sodium hydroxide, 1 to 5 parts by weight of sodium gluconate, 0.1 to 0.5 parts by weight of potassium hydroxide, 0.1 to 1 part by weight of polyoxyethylene-based nonionic surfactant, and 1 to 1 part of alkyl phenyl ether sulfonate There is provided a low temperature alkaline detergent composition comprising 5 parts by weight.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The low temperature alkaline detergent composition of the present invention is a mononuclear one-component alkaline degreasing composition in which a degreasing additive is added to the alkaline solution, so that pure alkali is added to pure water without the need to add an additive when cleaning the alkali in the field. Can be used. In addition, the low temperature alkali detergent composition of the present invention exhibits excellent degreasing performance at 50-60 ° C., which is lower than conventional 80 ° C.

Each component constituting the low temperature alkaline detergent composition of the present invention acts as follows, for example, in cleaning and degreasing cold rolled strip surfaces.

First, the rolled oil component and foreign matter remaining on the surface of the cold rolled strip are removed by sodium hydroxide which is the main component degreasing in the composition of the present invention. That is, the sodium hydroxide that saponifies reacts with the rolling oil attached to the strip surface to form soap, thereby lowering the surface tension between the strip surface and the contaminants attached to the strip surface, thereby improving degreasing power. At this time, the difference in the degree of saponification reaction increases with increasing temperature. Sodium hydroxide, which is used as a degreasing subject, is blended in the detergent composition at 20-40 parts by weight. If sodium hydroxide is present in less than 20 parts by weight, the cleaning and degreasing effect is low, and if it exceeds 40 parts by weight, the content of other solubility enhancers and other stabilizing aids used to increase the cleaning effect is relatively reduced. not.

The wet, penetrating sodium gluconate penetrates the contaminants attached to the strip surface to improve the wettability of the sodium hydroxide solution. Therefore, it promotes the saponification reaction and the emulsification action to improve the degreasing power. Sodium gluconate is blended in an alkali detergent composition at 1-5 parts by weight. If the sodium gluconate is less than 1 part by weight, it is not preferable in that it does not act as a water softener and does not contain cations such as Ca and Mg, which have a fatal effect on steel products. Is undesirable in that it generates unnecessary cost.

Potassium hydroxide is added in a small amount to the detergent composition compared to sodium hydroxide, but the saponification reaction with the rolled oil is more excellent. Thus, the cleaning composition of the present invention exhibits excellent degreasing ratio even at low temperatures. Potassium hydroxide is blended in the detergent composition at 0.1-0.5 parts by weight. If the content of potassium hydroxide is less than 0.1 parts by weight, saponification with KOH does not occur, and it is not preferable. If the content of more than 0.5 parts by weight, excess potassium hydroxide is generated, which is not preferable in that unnecessary cost is increased.

Polyoxyethylene-based nonionic surfactants, which osmotic, emulsify, and disperse the surface tension of the degreasing solution, are adsorbed at the interface between the solid and the liquid to reduce the interfacial energy, thereby reducing the inherent thermodynamic instability between the solid and the liquid. It decreases and increases the ζ- potential in the ion dissociative solution to prevent the coagulation by increasing the electrostatic repulsion between dispersed particles. The polyoxyethylene-based nonionic surfactant is also adsorbed on the solid dispersion particles to form a solvation layer around the particles to prevent aggregation of the dispersed particles. The polyoxyethylene-based nonionic surfactant is blended in the detergent composition at 0.1-1 part by weight. If the content of the polyoxyethylene nonionic surfactant is less than 0.1 part by weight, it is not preferable because it does not adsorb to the interface between the solid and the liquid and thus does not reduce the interfacial energy. It is not preferable in that it can cause environmental pollution. Examples of polyoxyethylene-based nonionic surfactants include, but are not limited to, polyoxyethylene ethers of glycerin esters, monoalkylpolyethylene glycol ethers, polyoxyethylene alcohols and alkylpolyoxyethylene glycols. These nonionic surfactants may be used alone or in mixtures.

In high alkali concentrations, nonionic surfactants are in an unstable state. Therefore, in order to maintain a stable emulsion state of the high alkali solution and the nonionic surfactant, an alkylphenyl ether sulfonate capable of artificially dissolving the polyoxyethylene surfactant is blended. By solubilizing the alkylphenyl ether sulfonate, it can be produced in a high concentration of alkaline composition. The alkylphenyl ether sulfonate is blended in the detergent composition at 1-5 parts by weight, preferably 2-4 parts by weight. If the alkylphenyl ether sulfonate is less than 1 part by weight, it is not preferable in that the polyoxyethylene nonionic surfactant cannot be completely dissolved. If the alkylphenyl ether sulfonate is more than 5 parts by weight, excess alkylphenyl ether sulfonate is generated, resulting in unnecessary cost. It is not preferable at that point.

The alkaline detergent composition may be diluted to use 2 to 4% by weight of sodium hydroxide in the alkaline detergent composition by adding pure water when cleaning and degreasing the cold rolled strip surface. At this time, it is not necessary to add another additive. If the sodium hydroxide dilution concentration is less than 2% by weight does not exhibit a sufficient degreasing, washing effect, if it exceeds 4% by weight is not preferable because the degreasing effect is not improved and the occurrence of environmental pollution, such as foaming may be a problem. In addition, the cleaning composition of the present invention can be applied to alkali degreasing at a low temperature of 50 ~ 60 ℃. Therefore, it has an energy saving effect.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following examples are provided to illustrate the present invention, and the present invention is not limited thereto.

EXAMPLE

Example  1-5

The degreasing efficiency and solution stability were evaluated by diluting the alkaline detergent composition having the composition ratio shown in Table 1 with pure water in the field so that the concentration of sodium hydroxide was 2.5% by weight.

A. Degreasing Efficiency

After storing the low temperature alkaline cleaning solution for one week, the mixture was diluted with pure water to maintain a sodium hydroxide concentration of 2.5% by weight and maintained at a temperature of 60 ° C. Cold rolled steel plate with rolling oil is cut into a size of 2.5cm × 10cm in alkaline cleaning solution at 60 ℃, immersed for 3 minutes, washed with distilled water, dried with hot air and analyzed by surface residual carbon analyzer. Surface residual carbon analyzer is a device that measures the amount of carbon (mg / dm ² ) per unit area by measuring the amount of carbon emitted by burning specimens with rolling oil at 200 ~ 400 ℃.

B. Solution Stability

The change of the alkaline detergent composition with the composition shown in Table 1 was observed for 1 week to evaluate the stability of the solution of the lamellae flow-free composition of the solution.

TABLE 1

Ingredients (parts by weight) Degreasing efficiency (%) Solution stability Sodium hydroxide Sodium Gluconate Potassium hydroxide Surfactant ⁽¹⁾ Alkylphenyl ether sulfonate Example 1 20 One 0.2 0.5 One 96 stability Example 2 25 2 0.3 0.6 1.5 95 stability Example 3 30 3 0.4 0.7 2 96 stability Example 4 35 4 0.5 0.8 3 96 stability Example 5 40 5 0.3 0.9 4 97 stability Comparative Example 1 20 One 0.2 0.5 - 65 Instability Comparative Example 2 25 2 0.3 0.6 - 70 Instability Comparative Example 3 30 3 0.4 0.7 - 68 Instability Comparative Example 4 30 3 0.4 0.7 0.5 75 Instability Comparative Example 5 30 3 0.4 0.7 5.5 85 Instability

(1) As the surfactant, polyoxyethylene ether of glycerin ester is used.

As shown in Table 1, when 1 to 5 parts by weight of alkylphenyl ether sulfonate is added to the alkaline solution, the stability of the surfactant is maintained, showing excellent degreasing efficiency even at low temperatures, and it can be prepared as a one-component alkaline cleaner. Able to know.

The alkaline detergent composition of the present invention not only shows excellent degreasing and cleaning effect at a low temperature of 50 to 60 ° C, but also has excellent solution stability, so that it can be used as a one-component low-temperature alkali cleaner and convenient to adjust the concentration. In addition, it is applicable at low temperatures, saving energy and logistics costs. On the other hand, it is expected to protect the environment by reducing energy consumption.

Claims (4)

20 to 40 parts by weight of sodium hydroxide, 1 to 5 parts by weight of sodium gluconate, 0.1 to 0.5 parts by weight of potassium hydroxide, 0.1 to 1 part by weight of polyoxyethylene-based nonionic surfactant, and 1 to 1 part of alkyl phenyl ether sulfonate A low temperature alkaline detergent composition comprising 5 parts by weight. The low temperature alkali detergent composition according to claim 1, wherein the low temperature alkali detergent composition is degreased at 50 to 60 ° C. The low temperature alkaline detergent composition according to claim 1, wherein the low temperature alkali detergent composition is used diluted to a sodium hydroxide concentration of 2-4% by weight. The method of claim 1, wherein the polyoxyethylene nonionic surfactant is at least one selected from the group consisting of polyoxyethylene ether, monoalkyl polyethylene glycol ether, polyoxyethylene alcohol and alkyl polyoxyethylene glycol of glycerin ester. Low temperature alkali detergent composition.