JP5753366B2 - Steel plate cleaning composition - Google Patents

Description

  The present invention relates to a steel plate cleaning composition used for cleaning dirt adhered to a steel plate (steel strip) made of iron, aluminum, copper, and the like, and a method for producing a cold-rolled steel plate using the same.

  Degreasing and cleaning of the surface of a steel sheet is necessary as a pretreatment for performing surface treatment such as plating and painting together with acid cleaning, and is a very large factor that determines the quality of a product. Examples of the dirt adhering to the steel sheet surface include oil dirt such as rolling oil and rust preventive oil adhering during cold rolling, and solid dirt such as iron powder. In particular, in cold rolling of steel sheets in recent years, rolling oil suitable for improving mill cleanliness and productivity has come to be used, and a cleaning agent having excellent cleaning properties for rolling oil is required.

  In response to the above problems, a detergent containing a specific amino ether (Patent Document 1), a detergent containing an oxypropylene group adduct of a polyhydric alcohol (Patent Document 2), 2 to 6 per molecule A cleaning agent containing an aliphatic compound having a polar group (Patent Document 3), a cleaning agent containing a surfactant and an antifoaming agent (Patent Document 4), and the like have been proposed.

JP 2001-316669 A JP 2007-154243 A Japanese Patent Laid-Open No. 7-41975 JP-A-60-169583

  However, if a surfactant having a high emulsifying power is used to improve detergency, the foaming property becomes high, so that the detergent overflows from the washing tank due to foaming, which is a big problem in operation. Therefore, in addition to detergency, the detergent is also required to have low foaming, that is, high defoaming property, from the viewpoint of workability. In the conventional cleaning composition, it was difficult to satisfy both the cleaning property and the defoaming property. In particular, as the cleaning is repeated, the rolling oil adhering to the surface of the steel sheet accumulates in the cleaning composition, so that the concentration of fatty acid soap in the cleaning composition increases and foaming becomes severe. With the conventional antifoaming agent added to the cleaning composition, foaming can be suppressed only when the concentration of fatty acid soap is low, and when the concentration of fatty acid soap is high, foam overflows from the cleaning tank, so the cleaning liquid can be discarded. I had to. For this reason, the production of the steel sheet cannot be continued for a long period of time, and the life of the cleaning liquid is short.

  The present invention provides a steel plate cleaning composition that can be a long-life cleaning agent because of its high cleaning properties and defoaming properties, and a method for producing a cold-rolled steel plate using the same.

That is, the present invention
Alkaline agent (a),
One or more nonionic surfactants (b) selected from the group consisting of compounds represented by the following general formula (1) or (2) and having an alkyl group or an alkenyl group;
(In the formulas (1) and (2), EO represents an oxyethylene group, PO represents an oxypropylene group, R ¹ represents an alkyl group or alkenyl group having 6 to 24 carbon atoms, and m and n represent an oxyethylene group. Each having an average addition mole number of 2 and each independently greater than 0, 2 ≦ m + n ≦ 120, R ² represents a linear or branched alkyl or alkenyl group having 6 to 24 carbon atoms, p Indicates the average number of moles of oxypropylene groups added, q indicates the average number of moles of oxyethylene groups added, and 0 ≦ p ≦ 9 and 5 ≦ q ≦ 30. But it ’s okay.)
Fatty acid amide (c),
An alcohol (d) having a branched alkyl group or alkenyl group having 8 to 24 carbon atoms and not having an oxyalkylene group added thereto; and
A steel sheet cleaning composition containing water,
Steel sheet cleaning agent, wherein the ratio {(b) / (d)} of the content of the nonionic surfactant (b) and the content of the alcohol (d) is 0.10 to 0.90. Composition.

The present invention is also a method for producing a cold rolled steel sheet comprising a rolling step of cold rolling a steel sheet in the presence of rolling oil and a cleaning step of cleaning the rolling oil adhering to the rolled steel sheet with a cleaning agent. And
In the said washing | cleaning process, it is related with the manufacturing method of the cold rolled steel plate which uses the cleaning composition for steel plates of the said this invention as a cleaning agent.

  According to the steel sheet cleaning composition of the present invention, it is possible to provide a cleaning agent having high cleaning properties and defoaming properties. In particular, even when the concentration of the fatty acid soap is high, the antifoaming property is high, so that the life of the cleaning agent can be extended. Moreover, according to the manufacturing method of the cold rolled steel plate of this invention, the washability of a steel plate surface can be improved and the manufacturing method of the cold rolled steel plate excellent in workability | operativity can be provided by the defoaming property improvement of a cleaning agent.

  Hereinafter, each component contained in the cleaning composition for steel sheet of the present invention will be described.

[Alkaline agent]
As the alkaline agent (a) used in the present invention, any water-soluble alkaline agent can be used from the viewpoint of securing the oil stain removal property of the steel plate cleaning composition and improving the cleaning property. Specific examples include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide, silicates such as sodium orthosilicate, sodium metasilicate and sodium sesquisilicate, phosphates such as trisodium phosphate, disodium carbonate And carbonates such as sodium hydrogen carbonate and dipotassium carbonate, and borate salts such as sodium borate. These are used singly or in combination of two or more. From the viewpoint of ensuring the oil stain removal property of the steel sheet cleaning composition and enhancing the cleaning performance, preferably sodium hydroxide, potassium hydroxide, sodium orthosilicate, sodium metasilicate, more preferably sodium hydroxide, water. Potassium oxide. The content of the alkali agent (a) is preferably 1.00 to 3.00% by weight, more preferably 1.20 to 2.70% by weight, and 1.30 to 2.50% by weight. % Is more preferable.

[Nonionic surfactant]
In the present invention, one or more nonionic surfactants (b) selected from the group consisting of compounds having an alkyl group or an alkenyl group, represented by the general formula (1) or (2). ) Is used as the activator component.

In the nonionic surfactant represented by the general formula (1), R ¹ represents an alkyl group or an alkenyl group and may be linear or branched. From the viewpoint of improving the detergency of the steel sheet cleaning composition, the carbon number of R ¹ is 6 to 24, preferably 8 to 20, more preferably 10 to 18, and 12 to 18 Even more preferably. From the viewpoint of improving the defoaming property of the steel sheet cleaning composition, R ¹ is preferably a linear alkyl group or alkenyl group. Moreover, in General formula (1), m and n show the average addition mole number of oxyethylene group (EO), and are numbers larger than 0 each independently. From the viewpoint of improving the cleanability of the steel sheet cleaning composition, 2 ≦ m + n ≦ 120, preferably 5 ≦ m + n ≦ 60, more preferably 8 ≦ m + n ≦ 30, and 8 ≦ m + n ≦ 20. It is more preferable that 8 ≦ m + n ≦ 15.

In the nonionic surfactant represented by the general formula (2), R ² represents a linear or branched alkyl group or alkenyl group. From the viewpoint of improving the cleaning properties of the steel sheet cleaning composition, the carbon number of R ² is 6 to 24, preferably 8 to 20, and more preferably 12 to 18. From the viewpoint of improving the defoaming property of the steel sheet cleaning composition, R ² is preferably a branched alkyl group or alkenyl group. Moreover, in General formula (2), p shows the average addition mole number of an oxypropylene group (PO), q shows the average addition mole number of an oxyethylene group (EO). From the viewpoint of improving the cleaning properties and antifoaming properties of the steel sheet cleaning composition, 0 ≦ p ≦ 9, preferably 0 ≦ p ≦ 5, and more preferably 1 ≦ p ≦ 3. Further, from the viewpoint of improving the cleaning property and the defoaming property of the steel sheet cleaning composition, 5 ≦ q ≦ 30, preferably 5 ≦ q ≦ 20, and more preferably 10 ≦ q ≦ 15. preferable. In the general formula (2), the portion surrounded by <> indicates that random addition or block addition may be used. In the case of a block, R ² O—PO _p EO _q —H may be used, and R ² _O-EO q _PO p -H any good. From the viewpoint of improving the detergency of the steel sheet cleaning composition, it is preferable that the R ² O group is block-added in the order of oxypropylene group-oxyethylene group, and the oxyethylene group is bonded to a terminal hydrogen atom. preferable.

Furthermore, from the viewpoint of improving the detergency and defoaming property of the steel sheet cleaning composition, the compound of the general formula (2) in which the oxyalkylene group bonded to the terminal hydrogen atom is an oxyethylene group is represented by the following general formula ( It is preferable that it is a compound represented by either (2-1), (2-2), and (2-3).

In the nonionic surfactant represented by any one of the general formulas (2-1), (2-2) and (2-3), R ³ , R ⁴ and R ⁵ are each independently a straight chain or A branched alkyl group or alkenyl group is shown. From the viewpoint of improving the cleaning properties and defoaming properties of the steel sheet cleaning composition, the carbon numbers of R ³ , R ⁴ and R ⁵ are each independently 6 to 24, preferably 8 to 20, More preferably, it is 12-18. From the viewpoint of improving the defoaming property of the steel sheet detergent composition, R ³ , R ⁴ and R ⁵ are preferably each independently a branched alkyl group or alkenyl group. Moreover, in general formula (2-1), (2-2), (2-3), x1-x8 shows the average addition mole number of an oxyethylene group (EO) each independently. From the viewpoint of improving the cleaning property and defoaming property of the steel sheet cleaning composition, each of x1 to x5 and x8 is a number of 1 or more, 0 <x6, 0 <x7, 4 ≦ x1 + x2 ≦ 30, 4 ≦ x3 + x4 ≦ 30, 4 ≦ x5 + x6 + x7 + x8 ≦ 30, 1 ≦ x6 + x7, preferably 5 ≦ x1 + x2 ≦ 20, 5 ≦ x3 + x4 ≦ 20, 5 ≦ x5 + x6 + x7 + x8 ≦ 20, more preferably 9 ≦ x1 + x2 ≦ 15 9 ≦ x3 + x4 ≦ 15 and 9 ≦ x5 + x6 + x7 + x8 ≦ 15. Moreover, in general formula (2-1), (2-2), (2-3), y1-y5 is a number which shows the average addition mole number of an oxypropylene group (PO) each independently, and is a cleaning agent for steel plates. From the viewpoint of improving the cleaning property and antifoaming property of the composition, 0 <y1 <x1 + x2, 0 <y2 <x3 + x4, 0.1 ≦ y3 + y5, 0 <y3, 0 <y4, 0 <y5, y3 + y4 + y5 <x5 + x6 + x7 + x8 0.5 <y1 <10, 0.5 <y2 <10, 0.5 <y3 + y4 + y5 <10, more preferably 1 <y1 <6, 1 <y2 <6, 1 <y3 + y4 + y5 <6. In the general formulas (2-1), (2-2), and (2-3), the part enclosed by () indicates that a block is added, and the part enclosed by [] is a random addition. Indicates that

  The weight average molecular weight of the nonionic surfactant (b) is preferably from 400 to 2400, more preferably from 450 to 1300, more preferably from 550, from the viewpoint of improving the detergency of the steel sheet detergent composition. More preferably, it is ˜1100.

Among the nonionic surfactants (b) listed above, from the viewpoint of improving the cleaning properties and defoaming properties of the steel sheet cleaning composition, it is represented by the general formula (1) or the general formula (2). In the nonionic surfactant, it is preferable to use a nonionic surfactant in which R ² is a branched alkyl group, and it is more preferable to use a nonionic surfactant represented by the general formula (1). The content of the nonionic surfactant (b) is preferably 0.02 to 0.30% by weight, more preferably 0.05 to 0.27% by weight, and 0.08 to More preferably, it is 0.25% by weight.

[Fatty acid amide]
The cleaning composition for steel sheet of the present invention contains a fatty acid amide (c) from the viewpoint of improving the defoaming property. As the fatty acid amide (c), monoamide or bisamide can be used, and examples of the monoamide include N-stearylamide, oleic acid amide, erucic acid amide, and stearylamide. Examples of bisamides include ethylene bisstearylamide, ethylene bispalmitylamide, ethylene bismyristylamide, ethylene bislaurylamide, ethylene bisoleylamide, propylene bisstearylamide, propylene bispalmitylamide, propylene bismyristylamide, propylene bislaurylamide , Propylene bis oleyl amide, butylene bis stearyl amide, butylene bis palmityl amide, butylene bis myristyl amide, butylene bis lauryl amide, butylene bis oleyl amide, methylene bis lauryl amide, methylene bis stearyl amide, hexamethylene bis stearyl amide, etc. It is done. Of these, ethylene bisstearylamide, ethylene bispalmitylamide, ethylene bislaurylamide, butylene bisstearylamide, and butylene bispalmitylamide are preferred from the viewpoint of improving antifoaming properties. Mitylamide and ethylene bismyristylamide are more preferred, ethylene bisstearylamide and ethylene bislaurylamide are more preferred, and ethylene bisstearylamide is even more preferred. These fatty acid amides (c) can be used alone or in combination of two or more.

  The steel plate cleaning composition of the present invention can be blended as a mixture (antifoaming agent) containing the fatty acid amide (c) when the fatty acid amide (c) is blended. In this case, the content of the fatty acid amide (c) in the antifoaming agent is preferably 1.0 to 10.0% by weight and more preferably 1.3 to 9.0% by weight from the viewpoint of improving the defoaming property. Preferably, 1.7 to 8.0% by weight is more preferable, and 2.0 to 7.0% by weight is even more preferable. Examples of components other than the fatty acid amide (c) in the antifoaming agent include hydrocarbon oils and polyoxyalkylene compounds. As an antifoaming agent containing such fatty acid amide (c), SN deformer 477 (manufactured by San Nopco), SN deformer 5013 (manufactured by San Nopco), Pronal A-3540 (manufactured by Toho Chemical Co., Ltd.), PN-188NR (Manufactured by Toho Chemical Industry Co., Ltd.). The content of the fatty acid amide (c) in the steel sheet cleaning composition is preferably 8 to 200 ppm, more preferably 16 to 120 ppm, and still more preferably 20 to 40 ppm.

  As the alcohol (d), 2-ethylhexyl alcohol, 3,5,5-trimethylhexyl alcohol, isodecyl alcohol, isotridecyl alcohol, isotetradecyl are used from the viewpoint of improving the defoaming property of the steel sheet cleaning composition. Saturated alcohols in which the branched chain is an alkyl group, such as alcohol, isopalmityl alcohol, isostearyl alcohol, unsaturated alcohols in which the branched chain is an alkenyl group, such as oleyl alcohol, linoleyl alcohol, etc., are isodecyl alcohol, Isotridecyl alcohol, isotetradecyl alcohol, and isostearyl alcohol are more preferable, and isotetradecyl alcohol and isostearyl alcohol are more preferable. These are used singly or in combination of two or more. The saturated alcohol in which the branched chain is an alkyl group can be obtained by hydroxylating a butylene or propylene polymer by the oxo method. The content of the alcohol (d) is preferably 0.02 to 0.40% by weight, more preferably 0.03 to 0.35% by weight, and 0.03 to 0.30% by weight. More preferably.

  In the present invention, from the viewpoint of improving the cleaning properties and defoaming properties of the steel sheet cleaning composition, the ratio of the content of the nonionic surfactant (b) and the content of the alcohol (d) { (B) / (d)} is 0.10 to 0.90. As described above, since the detergency and antifoaming properties are contradictory properties, it has been difficult to improve both physical properties. However, in the present invention, in a cleaning composition containing a specific composition, the ratio of the content of the nonionic surfactant (b) and the content of the alcohol (d) is set to a specific range. Therefore, it is possible to improve the detergency and defoaming unexpectedly, and even when the rolling oil adhering to the steel sheet surface accumulates and the concentration of fatty acid soap increases, the defoaming can be maintained. It has an amazing effect. From the same viewpoint, the ratio {(b) / (d)} of the content of the nonionic surfactant (b) and the content of the alcohol (d) is 0.10 to 0.80. Is more preferable, and 0.20 to 0.80 is more preferable.

  The cleaning composition for steel sheet of the present invention may further contain a chelating agent. It is considered that the chelating agent binds to and removes metal atoms in the soil to enhance the cleaning effect and improve the dispersibility of each agent in the cleaning composition of the present invention. Examples of chelating agents include glycine, nitrilotriacetic acid, aspartic acid, dihydroxyethylene glycine, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, iminodiacetic acid, triethylenetetraminehexaacetic acid, metaphenylenediaminetetraacetic acid, and hydroxyethyl. Aminocarboxylic acids such as alkali metal salts or lower amine salts such as ethylenediaminetriacetic acid and norleucine aminoacetic acid, and oxy such as alkali metal salts such as malic acid, citric acid, gluconic acid, glucoheptonic acid, mucoic acid, or lower amine salts Examples thereof include carboxylic acid type chelate builders. Of these, alkali metal salts such as ethylenediaminetetraacetic acid, aspartic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, glycolic acid and the like are preferable. These are used singly or in combination of two or more.

  The content of the chelating agent is preferably 0.01 to 5% by weight at the time of use (during cleaning) from the viewpoint of improving the cleaning properties and the dispersion stability of the steel plate cleaning composition. The content is more preferably from 01 to 3% by weight, and still more preferably from 0.05 to 3% by weight.

  From the viewpoint of improving the dispersion stability of the steel sheet cleaning composition, the steel sheet cleaning composition of the present invention may further contain polyacrylic acid or a salt thereof as a dispersant. As polyacrylic acid, product name: Aron A-200U (weight average molecular weight 2,000), Aron 20U (6,000), Aron A20UN (10,000), Aron A- 20ML (50,000), Aron A-30 (100,000), Aron A-10HL (200,000), Aron A-6007 (350,000), Aron A-7100G (500,000) ), Aron A-20LH (1,000,000) is preferably used. The cation constituting the polyacrylate is not particularly limited, but alkali metals, alkaline earth metals, and ammonium are preferable because they are easily available. In this invention, polyacrylic acid or its salt can be used 1 type or in combination of 2 or more types.

  The content of polyacrylic acid or a salt thereof is preferably 0.01 to 10% by weight, and preferably 0.05 to 5% by weight in use (during washing) from the viewpoint of improving the dispersion stability of the steel sheet cleaning composition. % Is more preferable, and 0.05 to 2% by weight is still more preferable.

  The steel sheet cleaning composition of the present invention comprises the alkali agent (a), the nonionic surfactant (b), the fatty acid amide (c), the alcohol (d), and, if necessary, a chelating agent, It is an aqueous composition prepared by blending polyacrylic acid or a salt thereof and water. From the viewpoint of ensuring detergency, the aqueous composition is preferably adjusted so that the pH is 12 or more, more preferably 13 or more, and even more preferably 14 or more. The pH can be adjusted with the alkali agent (a). In addition to the above-mentioned components, any additive can be added to the steel sheet cleaning composition of the present invention, but the additive can effectively adjust the pH with the alkali agent (a). Those having a small buffering effect on pH are preferred.

  Each component in the steel sheet cleaning composition of the present invention preferably has the following content at the time of use (at the time of cleaning) from the viewpoint of improving the cleaning property and defoaming property.

  The content of the alkali agent (a) is preferably 1.00 to 3.00% by weight, more preferably 1.20 to 2.70% by weight, and 1.30 to 2.50% by weight. % Is more preferable. The content of the nonionic surfactant (b) is preferably 0.02 to 0.30% by weight, more preferably 0.05 to 0.27% by weight, and 0.08 to More preferably, it is 0.25% by weight. The content of the fatty acid amide (c) is preferably 8 to 200 ppm, more preferably 16 to 120 ppm, and still more preferably 20 to 40 ppm. The content of the alcohol (d) is preferably 0.02 to 0.40% by weight, more preferably 0.03 to 0.35% by weight, and 0.03 to 0.30% by weight. More preferably.

  In addition, when a mixture containing a fatty acid amide (antifoaming agent) is added at the time of preparation of the cleaning agent, the content of the antifoaming agent is in use (during cleaning) from the viewpoint of improving the detergency and improving the antifoaming property. 0.01 to 0.70% by weight, more preferably 0.03 to 0.60% by weight, and still more preferably 0.05 to 0.50% by weight.

  The water is preferably deionized water. The concentration of each component in the steel sheet cleaning composition can be controlled by water.

  The cleaning composition for steel sheet of the present invention, when used (cleaning), the alkali agent (a), the nonionic surfactant (b), the fatty acid amide (c), and the alcohol (d) ) Is preferably used, but it is preferably prepared as a concentrated composition in consideration of improvement in storage stability after production, improvement in transportation efficiency, and the like. The concentrated composition is diluted with water at the time of washing. That is, the cleaning composition for steel sheet of the present invention may be a cleaning composition used for cleaning, or may be a concentrated composition that is concentrated prior to cleaning and diluted at the time of use.

  In the concentrated composition, the content of the alkali agent (a) is preferably 5 to 48 weights from the viewpoint of improving the stability as a slurry and maintaining the viscosity at the time of transporting the cleaning composition by piping. %, More preferably 10 to 45% by weight, still more preferably 20 to 42% by weight.

  Further, in the concentrated composition, the contents of the nonionic surfactant (b), the fatty acid amide (c) and the alcohol (d) are improved in storage stability of the steel sheet cleaning composition after production, From the viewpoint of improving transport efficiency and stability as a slurry, it is preferably 0.1 to 8.0% by weight, 0.01 to 0.60% by weight, and 0.4 to 10.0% by weight, It is more preferable that they are 0.4-6.0 weight%, 0.03-0.50 weight%, and 0.6-8.0 weight%, 0.5-4.0 weight%, 0.03- More preferably, they are 0.40 weight% and 0.7-7.0 weight%.

  In addition, when a chelating agent is added, the content of the chelating agent in the concentrated composition is preferably from the viewpoint of improving the storage stability of the steel sheet cleaning composition after production, improving the transport efficiency, and improving the stability as a slurry. Is 0.05 to 20% by weight, more preferably 0.1 to 15% by weight, still more preferably 0.5 to 10% by weight.

  Moreover, when adding polyacrylic acid or its salt, content of polyacrylic acid or its salt in a thick composition improves the storage stability of the cleaning composition for steel plates after production, improves transportation efficiency, and as a slurry. From the viewpoint of improving stability, it is preferably 0.1 to 20% by weight, more preferably 0.2 to 10% by weight, and still more preferably 0.3 to 5% by weight.

  In addition, the total content of the alkali agent (a), the nonionic surfactant (b), the fatty acid amide (c), and the alcohol (d) in the steel sheet cleaning composition related to the concentrated composition is: From the viewpoint of ensuring the cleaning properties and defoaming properties of the steel sheet cleaning composition, 5 to 60% by weight is preferred, 10 to 55% by weight is more preferred, and 20 to 50% by weight is even more preferred. On the other hand, the content of water is preferably 40 to 95% by weight, more preferably 45 to 90% by weight, and still more preferably 50 to 80% by weight.

  The steel sheet cleaning composition of the present invention comprises the alkali agent (a), the nonionic surfactant (b), the fatty acid amide (c), the alcohol (d), and, if necessary, a chelating agent, Although it is an aqueous composition prepared by blending polyacrylic acid or a salt thereof and water, each component is prepared in advance as a kit of one agent or two or more agents, before use, For example, they may be mixed or further diluted by adding water, and each kit component may be individually added to the washing tank and diluted with water as necessary.

  The steel sheet cleaning composition of the present invention is suitable as a degreasing detergent on the surface of a steel sheet, and in particular, as a detergent used for removing rolling oil adhering to a cold rolled steel sheet. That is, the steel sheet detergent composition of the present invention includes a rolling process in which a steel sheet is cold-rolled in the presence of rolling oil, and a cooling process in which the rolling oil adhering to the rolled steel sheet is washed with a cleaning agent. In the method for producing a hot-rolled steel sheet, it can be suitably used as a cleaning agent in the cleaning step. In addition, in the manufacturing method of the said cold rolled steel plate, the method similar to the past can be employ | adopted except using the cleaning composition of this invention as a cleaning agent in the said washing | cleaning process. In addition, the total content of the nonionic surfactant (b) and the fatty acid amide (c) is 0.02 to 0 at the time of use (at the time of washing) from the viewpoint of improving the washing property and improving the defoaming property. .35% by weight is preferable, 0.05 to 0.30% by weight is more preferable, and 0.08 to 0.27% by weight is still more preferable.

  The step of cold rolling is a processing step of cold rolling a steel sheet in the presence of rolling oil at an iron mill or the like. In the cleaning step, the rolling oil is cleaned and removed using the cleaning composition of the present invention by continuous cleaning, that is, immersion cleaning, spray cleaning, brush cleaning, electrolytic cleaning, and the like. In particular, the cleaning composition of the present invention is suitably applied when the rolled steel sheet is passed through an alkaline immersion cleaning tank and / or an alkaline electrolytic cleaning tank when the cleaning process is immersion and / or electrolytic cleaning. Is done.

  The steel sheet cleaning composition of the present invention is effective for a steel sheet to which a rolling oil containing 50% by weight or more of a carboxylic acid ester adheres, and a rolling oil containing 70% by weight or more of a carboxylic acid ester. It is more effective for a steel plate to which is attached. As the carboxylic acid ester, a carboxylic acid ester made from a dimer acid or a polymer acid of an aliphatic unsaturated acid having 16 to 20 carbon atoms such as zomarinic acid, palmitic acid, oleic acid, linoleic acid, gadoleic acid, tall oil fatty acid, etc. , Propylene glycol, ethylene glycol, diethylene glycol, neopentyl glycol, butanediol, pentanediol, polyoxyethylene glycol, polyoxypropylene glycol, trimethylolpropane, pentaerythritol, glycerin and the like and fatty acids having 6 to 22 carbon atoms Carboxylic acid ester made from aliphatic carboxylic acid, carboxylic acid ester made from aliphatic alcohol having 1 to 12 carbon atoms and aliphatic carboxylic acid having 6 to 22 carbon atoms, polyhydric alcohol and fat having 6 to 22 carbon atoms Tribe Synthetic esters based on carboxylic acid esters based on xylcarboxylic acid, polybasic acids such as adipic acid, sebacic acid, azelaic acid, phthalic acid, trimellitic acid, pyromellitic acid and aliphatic alcohols having 1 to 12 carbon atoms And oxyethylene groups, oxypropylene groups of the alcohols, and esters with adducts of oxybutylene groups.

  Further, the steel sheet cleaning composition of the present invention is effective for a steel sheet to which a rolling oil having an acid value of 10 mgKOH / g or more is attached, and a rolling oil having an acid value of 20 mgKOH / g or more. It is more effective for the steel sheet to be adhered. The steel sheet cleaning composition of the present invention is particularly effective for a steel sheet containing 50% by weight or more of a synthetic ester and to which rolling oil having an acid value of 10 mgKOH / g or more adheres.

  Further, the steel sheet cleaning composition of the present invention is effective for a steel sheet to which a rolling oil containing 10% by weight or more of an ester having a viscosity at 40 ° C. of 70 Pa · s or more adheres. Is more effective for a steel plate to which a rolling oil containing 20% by weight or more adheres. In particular, this is effective for a steel sheet to which a rolling oil having a viscosity of 40 Pa, preferably 100 Pa · s or more, and more preferably 150 Pa · s or more is adhered. Examples of the high-viscosity ester include a carboxylic acid ester using a dimer acid or a polymer acid of an aliphatic unsaturated acid having 16 to 20 carbon atoms, a polyhydric alcohol and an aliphatic carboxylic acid having 6 to 22 carbon atoms. Examples thereof include carboxylic acid esters in which at least one hydroxyl group of the polyhydric alcohol is left as a raw material, and carboxylic acid esters in which the above polyhydric alcohol and an aliphatic hydroxycarboxylic acid having 6 to 22 carbon atoms are used as raw materials. In addition, the viscosity of the ester can be measured by an automatic viscosity measuring device VMC-252 (JIS K2283) manufactured by Koiso Co., Ltd. In addition, the cleaning composition for steel sheets of the present invention is effective in addition to esters, and is effective for compounds such as polybutene, for example.

<Detergency>
(1) Steel plate to be cleaned All steel plates to be cleaned were prepared by the following procedure. That is, a steel plate to be cleaned was obtained by cutting a steel plate having a thickness of 0.5 mm cold-rolled with a synthetic ester rolling oil containing 30% by weight of palm oil into a size of 25 mm × 50 mm. The amount of oil adhered to the steel plate to be cleaned was 100 mg / m ² .

(2) Cleaning test procedure All cleaning tests were performed according to the following procedure. That is, the steel plate to be cleaned is equidistant and centered from a pair of electrode plates each having a size of 100 mm in length and 50 mm in width (distance between the electrodes is 20 mm) in the cleaning composition for steel plate (new solution) of each example. Soaked for 1 second. Thereafter, the steel plate potential was kept negative for 0.5 seconds at a current density of 10 A / dm ² , and then the steel plate potential was kept positive for 0.5 seconds, followed by electrolytic cleaning. Next, the washed steel sheet was rinsed by immersing it in 60 ° C. water for 5 seconds, and then dried with warm air. The temperature of the test detergent was 60 ° C.

(3) Method for measuring the amount of remaining adhered oil The amount of adhered oil remaining on the surface of the steel sheet after the cleaning test (the amount of remaining adhered oil) was measured using a steel sheet adhered oil amount measuring device EMIA-111 (manufactured by Horiba, Ltd.). The measured value is an average value of five measurements. It represents that it is excellent in detergency, so that there is little residual oil amount.

<Defoaming property>
200 mL of the cleaning composition (new solution) of each example was placed in a 1000 mL measuring cylinder, and the liquid temperature was kept at 60 ° C. Thereafter, a mixture of palmitic acid and oleic acid (weight ratio of palmitic acid: oleic acid = 13: 5) as a model of the fatty acid soap component generated during the actual cleaning of the steel sheet is 0 with respect to 100 parts by weight of the cleaning composition. .5 parts by weight (0.2 parts by weight of Example 2 only) was added to this mixture, and a glass ball filter (Kinoshita Rika Kogyo Co., Ltd., Kinoshita type glass ball filter 503G [spherical diameter: 20 mm, filter particles: 20 to 30 μm, The outer diameter of the tube: 8 mm, the tube length: 300 mm]), nitrogen was flowed at 270 mL / min, and the volume of the foam after 5 minutes (mL) (the total volume of the substance present in the graduated cylinder after 5 minutes—200 mL). It was measured. The smaller the volume, the better the defoaming property.

(Examples and Comparative Examples)
Each component shown in Table 1 (Example) and Table 2 (Comparative Example) (the balance is deionized water) is mixed with a homogenizer for 10 minutes to prepare a detergent composition, and the above-described evaluation of detergency and defoaming property (The pH of the cleaning composition was 14 in all cases). The results are shown in Tables 1 and 2. In Tables 1 and 2, the ethylene bisstearyl amide, the polyoxyalkylene compound represented by C ₄ H ₉ —O— (PO) ₃₁ —H, and the mineral oil-based hydrocarbon are defoaming agents except for Comparative Example 5. (SN deformer 477, manufactured by San Nopco) was blended in the state of a mixture. For Comparative Example 5, a polyoxyalkylene compound represented by C ₄ H ₉ —O— (PO) ₃₁ —H and a mineral oil-based hydrocarbon were each blended alone. In addition, structural formulas of compounds A to F (all manufactured by Kao Corporation) shown in Tables 1 and 2 are shown below.

Moreover, the average addition mole number of the oxyethylene group (EO) and the oxypropylene group (PO) in the compounds A to E is CDCl based on Kobo Shobo Publishing “Surfactant Analysis” (published in 1987) P255 to P273. _{The amount} of each compound dissolved in ₃ in 2% was used as a sample and quantified from an NMR spectrum (NMR apparatus: MERCURY400, manufactured by Varian).

  From the results of Tables 1 and 2, it was confirmed that the cleaning composition of the present invention has better cleaning properties against oil stains adhering to the steel sheet surface and antifoaming properties than the comparative example. It was.

Claims (6)

Alkaline agent (a),
One or more nonionic surfactants (b) selected from the group consisting of compounds represented by the following general formula (1) or (2) and having an alkyl group or an alkenyl group;


(In the formulas (1) and (2), EO represents an oxyethylene group, PO represents an oxypropylene group, R ¹ represents an alkyl group or alkenyl group having 6 to 24 carbon atoms, and m and n represent an oxyethylene group. Each having an average addition mole number of 2 and each independently greater than 0, 2 ≦ m + n ≦ 120, R ² represents a linear or branched alkyl or alkenyl group having 6 to 24 carbon atoms, p Indicates the average number of moles of oxypropylene groups added, q indicates the average number of moles of oxyethylene groups added, and 0 ≦ p ≦ 9 and 5 ≦ q ≦ 30. But it ’s okay.)
Fatty acid amide (c),
An alcohol (d) having a branched alkyl group or alkenyl group having 8 to 24 carbon atoms and not having an oxyalkylene group added thereto; and
A steel sheet cleaning composition containing water,
Steel sheet cleaning agent, wherein the ratio {(b) / (d)} of the content of the nonionic surfactant (b) and the content of the alcohol (d) is 0.10 to 0.90. Composition. The nonionic surfactant (b) is a compound selected from the formula (2), and the formula (2) is represented by the following formulas (2-1), (2-2) and (2-3) The steel sheet cleaning composition according to claim 1, which is either of them.


(In the above formulas (2-1), (2-2) and (2-3), R ³ , R ⁴ and R ⁵ are each independently a linear or branched alkyl group or alkenyl having 6 to 24 carbon atoms. X1 to x8 each independently represent an average number of moles of the oxyethylene group added, and x1 to x5 and x8 are 1 or more, and 0 <x6, 0 <x7, 4 ≦ x1 + x2 ≦ 30 4 ≦ x3 + x4 ≦ 30, 4 ≦ x5 + x6 + x7 + x8 ≦ 30, 1 ≦ x6 + x7, and y1 to y5 are numbers independently representing the average added mole number of oxypropylene groups, 0 <y1 <x1 + x2, 0 <y2 <x3 + x4 , 0.1 ≦ y3 + y5, 0 <y3, 0 <y4, 0 <y5, y3 + y4 + y5 <x5 + x6 + x7 + x8, the part enclosed in () indicates that a block is added, and the part enclosed in [] is (Indicates random addition.)   In use, the content of the alkali agent (a), the nonionic surfactant (b), the fatty acid amide (c), and the alcohol (d) is 1.00 to 3.00% by weight, respectively. The cleaning composition for steel plates according to claim 1 or 2, which is 0.02 to 0.30 wt%, 8 to 200 ppm, and 0.02 to 0.40 wt%.   Furthermore, the cleaning composition for steel plates of any one of Claims 1-3 containing a chelating agent.   Furthermore, the cleaning composition for steel plates of any one of Claims 1-4 containing polyacrylic acid or its salt. A method for producing a cold rolled steel sheet, comprising: a rolling process for cold rolling a steel sheet in the presence of rolling oil; and a cleaning process for cleaning the rolling oil adhered to the rolled steel sheet with a cleaning agent,
In the said washing | cleaning process, the manufacturing method of the cold rolled steel plate which uses the cleaning composition for steel plates in any one of Claims 1-5 as a cleaning agent.