JP2007270287A - Detergent composition for batch-annealed steel strip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detergent composition for a batch-annealed steel strip, which has a high detergency and is capable of reducing the degree of adhesion of the steel strip after batch annealing in a manufacturing step of the steel step comprising a washing step and a batch annealing step. <P>SOLUTION: The detergent composition for the batch-annealed steel strip contains a silicate (a), a gluconic acid and/or its salt (b) and water. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning composition for batch-type annealed steel strip and a steel strip manufacturing method having a cleaning step using the composition.

  The steel strip needs to be cleaned of dirt such as rolling oil, hydraulic oil, iron powder, and iron soap generated and adhered during rolling, and then subjected to annealing for imparting workability. Here, annealing is annealing or annealing, and refers to the process of heating to a suitable temperature once, holding it there, and then gradually cooling (Chemical Dictionary 1 volume P208 (Showa 56)), iron or steel. The purpose is to soften the crystal, to adjust the crystal structure or to remove internal stress.

  The annealing methods include batch annealing and continuous annealing. Among these, the batch annealing has a problem of adhesion or seizure of a steel strip, which contributes to a decrease in yield.

  In order to prevent such adhesion, it is known that silicon deposited on the surface of the steel strip is effective when electrolytic cleaning (electrolytic cleaning) is performed using a cleaning agent containing sodium silicate.

Patent Document 1 discloses a concentrated alkaline cleaning agent having a specific composition that is necessary for removing dirt such as oily substances adhering to the metal surface and dirt such as metal powder in the previous stage of the post process such as the annealing process. ing. Patent Document 2 discloses a metal detergent composition containing an alkali base, a surfactant, and a compound selected from a specific group. Patent Document 3 discloses an alkaline aqueous solution composition that contains an alkali agent, a nonionic surfactant, and a solubilizer and is useful as a cleaning agent for metals and the like.
Japanese Patent Application Laid-Open No. 11-181587 JP-A-60-121284 JP 2004-182801 A

  Patent Document 1 relates to a suspension-type cleaning agent using an alkali agent at a high concentration, and it is difficult to say that it discloses a technique in a mode suitable as a cleaning agent having an adhesion reduction effect for annealing. Moreover, it was found that when an alkali agent was actually prepared within the range of the examples in Patent Document 1, the alkali agent was solidified and could not be put into practical use. In such Patent Document 1, it is not possible to obtain a cleaning agent that is sufficiently stable and that is excellent in cleaning properties and the effect of reducing the adhesion of a steel strip after batch annealing. On the other hand, with respect to Patent Document 2, further improvement is desired for the cleaning property and the effect of reducing the adhesion of the steel strip after batch annealing. In Patent Document 3, there is no mention of the problem of achieving both the cleanability of the steel strip before annealing and the effect of reducing the adhesion of the steel strip after batch annealing.

  An object of the present invention is to provide a cleaning composition for a batch-type annealed steel strip, which can reduce the degree of adhesion of the steel strip after the batch-type annealing and the high cleanability in the steel strip production process including the cleaning step and the batch-type annealing. It is providing the steel strip manufacturing method which has the washing | cleaning process which uses a composition.

  The present invention is for a batch-type annealed steel strip containing silicate (a) [hereinafter referred to as component (a)], gluconic acid and / or a salt thereof (b) [hereinafter referred to as component (b)], and water. The present invention relates to a cleaning composition.

  Moreover, this invention is a steel strip manufacturing method which has a batch type annealing process after an electrolytic cleaning process, Comprising: Steel strip manufacture which uses the cleaning composition for batch type annealing steel strips of the said invention in an electrolytic cleaning process Regarding the method.

  According to the present invention, in a manufacturing process of a steel strip including a cleaning process and batch-type annealing, a cleaning composition for a batch-type annealed steel strip that can reduce high cleaning properties and adhesion of the steel strip after batch-type annealing, and the concerned The steel strip manufacturing method which has the washing | cleaning process using a composition can be provided.

  The cleaning composition for a batch-type annealed steel strip of the present invention is a composition containing a combination of silicate and gluconic acid and / or a salt thereof. It was completed by utilizing the fact that it was excellent at the same time for reducing the adhesion of the steel strip later.

[Component (a)]
The component (a) of the composition of the present invention is a silicate such as sodium salt or potassium salt such as orthosilicic acid, metasilicic acid or sesquisilicic acid, preferably orthosilicate or sodium salt or potassium salt of metasilicic acid. More preferred are sodium salt and potassium salt of orthosilicic acid, and more preferred are these sodium salts.

  Silicate makes the cleaning composition for steel strip alkaline, and removes dirt such as oily substances and metal powder on the steel strip, and at the same time combined with gluconic acid and / or a salt thereof described later. Due to the action, the degree of adhesion of the steel strip after batch annealing is reduced.

[Component (b)]
Component (b) of the composition of the present invention is gluconic acid and / or a salt thereof. The component (b) further promotes the removal of dirt such as oily substances on the steel strip and dirt such as metal powder by the action of the combination with the silicate described above.

[Cleaning composition for batch-type annealed steel strip]
The steel band cleaning composition of the present invention uses tap water, ion exchange water, industrial water, etc. as a solvent, and uses an organic water-soluble solvent such as a lower alcohol as long as the effects of the present invention are not impaired. Also good.

[Component (c)]
The composition of the present invention is preferably an aqueous solution because the component (a) and the component (b) are stable without phase separation and the aqueous solution is fluid. It is preferable because the cleaning component can be stably and uniformly supplied to the tank, and the desired effects of detergency and reduction of the adhesion of the steel strip after annealing are exhibited. In order to obtain an aqueous solution containing the component (a) and the component (b), the composition of the present invention is at least selected from compounds represented by the following general formulas (1) to (3) as the component (c). It is preferable to contain 1 or more types.

R ¹ —X— (CH ₂ ) _m COOM ¹ (1)
R ² -COOM ² (2)
R ³ -COOM ³ (3)
[Wherein, R ¹ represents a saturated or unsaturated linear or branched aliphatic hydrocarbon group having 4 to 22 carbon atoms or an aromatic hydrocarbon group having 5 to 18 carbon atoms, and X represents a group> NH, > N (CH ₂ ) _n COOM ¹ or> CHCOOM ¹ R ² represents a saturated or unsaturated linear aliphatic hydrocarbon group having 3 to 22 carbon atoms or an aromatic hydrocarbon group having 5 to 18 carbon atoms. R ³ represents a saturated or unsaturated branched aliphatic hydrocarbon group having 4 to 22 carbon atoms. M ¹ , M ² and M ³ each represent a hydrogen atom, an alkali metal, an aliphatic amine having 1 to 4 carbon atoms, ammonia or an alkanolamine, and m and n each represent an integer of 1 to 3. ]

In the general formula (1), R ¹ is preferably a saturated or unsaturated linear or branched aliphatic hydrocarbon group having 5 to 18 carbon atoms or an aromatic hydrocarbon group having 5 to 18 carbon atoms, and has 6 carbon atoms. More preferred are -12 saturated or unsaturated linear or branched aliphatic hydrocarbon groups. As the compound represented by the general formula (1) [hereinafter referred to as component (c-1)], R ¹ is an alkyl group or alkenyl group having 5 to 17 carbon atoms, or a phenyl group, and X is> NH or> N. (CH ₂ ) _n COOM ¹ , m and n are each preferably an integer of 1 to 3. Specifically, the following is exemplified. Among the compounds exemplified below, compounds having an i-C ₈ H ₁₇ group and compounds having an n-C ₁₂ H ₂₅ group are more preferred.

[Wherein, M ¹ has the same meaning as described above. ]

In the general formula (2), R ² is preferably a saturated or unsaturated linear aliphatic hydrocarbon group having 4 to 12 carbon atoms or an aromatic hydrocarbon group having 5 to 18 carbon atoms, and having 4 to 12 carbon atoms. A saturated or unsaturated linear aliphatic hydrocarbon group is more preferred. The compound represented by the general formula (2) [hereinafter referred to as component (c-2)] is a straight-chain saturated fatty acid or straight-chain unsaturated fatty acid having 4 to 23 carbon atoms, or carbon atoms having an aromatic group. -19 carboxylic acids or salts thereof. Examples of linear saturated fatty acids include caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, butyric acid, valeric acid and the like. Examples of linear unsaturated fatty acids include caproleic acid, oleic acid, 9-undecylenic acid, elaidic acid, 10-undecylenic acid, 2-laurolenic acid, pasenic acid, lindelic acid, succinic acid, 5-lauroleic acid, 11-laurolein Acid, 2-palmitoleic acid, 7-palmitoleic acid, cis-9-palmitoleic acid, zomarinic acid, trans-9-palmitoleic acid, tuzuic acid, 5-myristoleic acid, myristoleic acid, petrothelinic acid, petroceniridine acid Etc. As the carboxylic acid having an aromatic group, phenylacetic acid, β-phenylpropionic acid, γ-phenylacetic acid, δ-phenylvaleric acid, τ-phenylcaproic acid, ζ-phenylenatonic acid, η-phenylcaprylic acid, θ- Examples include phenyl pelargonic acid, ι-phenyl capric acid, naphthenic acid and toluic acid.

  Among these, a linear saturated fatty acid having 4 to 18 carbon atoms or a linear unsaturated fatty acid or a salt thereof is preferable, and a linear saturated fatty acid having 4 to 12 carbon atoms is particularly preferable.

In the general formula (3), R ³ is preferably a saturated or unsaturated branched aliphatic hydrocarbon group having 4 to 12 carbon atoms. The compound represented by the general formula (3) [hereinafter referred to as component (c-3)] is a branched saturated fatty acid or branched unsaturated fatty acid having 5 to 23 carbon atoms or a salt thereof. Examples of branched chain saturated fatty acids include 2-ethylhexanoic acid, isopalmitic acid, isostearic acid, neoheptanoic acid, 2-butyl-5-methylpentanoic acid, 2-isobutyl-5-methylpentanoic acid, 4,6-dimethyloctane Acid, 4,7-dimethyloctanoic acid, 2,3-dimethyloctanoic acid, 2,3-dimethylnonanoic acid, 4,8-dimethylnonanoic acid, 2-butyl-5-methylhexanoic acid, 2-methylundecanoic acid, 10-methylundecanoic acid, 4,4-dimethyldecanoic acid, 2-ethyl-3-methylnonanoic acid, 2,2-dimethyl-4-ethyloctanoic acid, 2-methyldocosanoic acid, 3-methyldocosanoic acid, (+)-3D -Methyldocosanoic acid, 2-propyl-3-methylnonanoic acid, 12-methyltridecanoic acid, 2,2-dimethyldodecanoic acid, 2,3-di- Chirudodekan acid, 4,10-dimethyl dodecanoic acid, and 2-butyl-3-methylnonanoic acid. Examples of branched chain unsaturated fatty acids include trans-2-methyl-2-pentenoic acid, trans-4-methyl-3-pentenoic acid, cis-2-methyl-2-hexenoic acid, trans-2-methyl-2- Hexenoic acid, 2-methylene-hexanoic acid, 3,4-dimethyl-3-pentenoic acid, trans-2-methyl-2-heptenoic acid, 3-methyl-2-nonenoic acid, 3-methyl-3-nonenoic acid, 5-methyl-2-undecenoic acid, 2,4-dimethyl-2-decenoic acid, 5,9-dimethyl-2-decenoic acid, 2-methyl-2-dodecenoic acid, (−)-5-methyl-2- Examples include tridecenoic acid, L (+)-2,4-dimethyl-2-dodecenoic acid, L (+)-2,5-dimethyl-2-tridecenoic acid, and the like.

  In these, a C5-C18 branched saturated fatty acid or branched unsaturated fatty acid, or those salts are preferable, and a C5-C12 branched saturated fatty acid is especially preferable.

In the general formula (1) to (3), the alkali metal represented by M ^1, M ^2, M ^3, potassium, sodium, etc., the aliphatic amine having 1 to 4 carbon atoms, methylamine, ethylamine, propylamine Examples of alkanolamines such as amine, butylamine, ethylenediamine, and diethylenetriamine include monoethanolamine, diethanolamine, triethanolamine, and other alkanolamines having 2 to 10 carbon atoms. M ¹ , M ² and M ³ are preferably a hydrogen atom or an alkali metal.

  The component (c) of the present invention comprises the component (c-1) from the viewpoint of solubilization of the nonionic surfactant in the alkaline aqueous solution, and from the viewpoint of productivity and more stable solubilization, the component (c) It is preferable to combine c-2) or component (c-3). From such a viewpoint, the weight ratio (c-1) / (c-2) or (c-1) in the case of combining the component (c-1) with the component (c-2) or the component (c-3) / (C-3) is preferably 0.1 / 1 to 70/1, more preferably 0.4 / 1 to 50/1, and still more preferably 0.7 / 1 to 30/1.

  In the present invention, the component (c-1) is essential, and the component (c-2) or the component (c-3) is blended, so that the nonionic surfactant into the alkaline aqueous solution can be used in a small amount. Can be solubilized. Solubilization of nonionic surfactant in alkaline aqueous solution is solubilized by making shelf-layer micelles by orienting highly hydrophilic component (c-1) to nonionic surfactant with reduced hydrophilicity. It is estimated that However, since it is estimated that the component (c-1) having excellent base resistance is dissolved in a large amount and cannot efficiently contribute to micelle formation, the component (c-2) having low solubility in an alkaline aqueous solution. Alternatively, it is considered that mixed micelles are efficiently formed by using (c-3) together and orienting to component (c-1), and the amount of component (c-1) used can be reduced.

  The composition of the present invention consisting of an aqueous solution has a composition temperature of 50 ° C. or higher, particularly those containing the component (c) can be stably stored at a low composition temperature (40 to 50 ° C.). It is more preferable because it can reduce the degree of adhesion of the steel strip after high cleanability and batch-type annealing.

[Component (d)]
The composition of the present invention comprises, as component (d), an alkylene oxide adduct of an alcohol having 4 to 24 carbon atoms, preferably a monohydric alcohol having 4 to 24 carbon atoms, and an alkyl (carbon group having 5 to 12 carbon atoms). It is preferable to contain one or more nonionic surfactants selected from phenol alkylene oxide adducts.

  Ingredient (d) reinforces the effect of exfoliating and inhibiting reaggregation of oil components on the steel strip surface, dirt such as oily substances on the steel strip, dirt such as metal powder, or soils derived therefrom.

  Among these, the component (d) is preferably an alkylene oxide adduct of a C 4-24 alcohol, and further a C 4-24 monohydric alcohol.

  Component (d) is preferably one having an HLB of 4.3 to 8.2, more preferably 5 to 7.9, as determined by the Davis method.

In addition, HLB of a component (d) is HLB by the Davis (Davies) method, and is a value represented by the following formula, and the number of hydrophilic groups and the number of lipophilic groups in the following formula are “new surface active agent” The values described in Table 5-1-3 on page 235 of “Handbook”, Engineering Books Co., Ltd., May 1, 1996 are adopted.
HLB = Σ [base number of hydrophilic group of component (d)] + Σ [base number of lipophilic group of component (d)] + 7

  Among the component (d), examples of the alkylene oxide adduct of alcohol having 4 to 24 carbon atoms include nonionic surfactants selected from compounds represented by the following general formulas (I) to (V).

R ¹ O- <EO _n / PO _m > -H (I)
R ² O- (EO) _x1- (PO) _y1- (EO) _x2 -H (II)
R ³ O- [EO _x3 / PO _y2 ]-(EO) _x4 -H (III)
R ⁴ O- (EO) _x5- [EO _x6 / PO _y3 ]-(PO) _y4- [EO _x7 / PO _y5 ]-(EO) _x8 -H (IV)
R ⁵ O- (EO) _z -H (V)
[Wherein, EO represents an oxyethylene group, and PO represents an oxypropylene group. R ¹ is a linear or branched alkyl group or alkenyl group having 4 to 14 carbon atoms, n is an average addition mole number of an oxyethylene group, m is an average addition mole number of an oxypropylene group, and n is 0 to 20 , M is a number from 0 to 20 inclusive. R ² , R ³ and R ⁴ each independently represents a linear or branched alkyl or alkenyl group having 6 to 24 carbon atoms, and x1, x2, x3, x4, x5, x6, x7 and x8 represent ethylene oxide. X1, x2, x3, x4, x5 and x8 are numbers of 1 or more, x1 + x2 ≧ 4, x3 + x4 ≧ 4, x5 + x6 + x7 + x8 ≧ 4, and x6 + x7 ≧ 1. y1, y2, y3, y4 and y5 are numbers indicating the average added mole number of propylene oxide, and 0 <y1 <x1 + x2, 0 <y2 <x3 + x4, y3 + y5 ≧ 0.1, y3 ≧ 0, y4 ≧ 0, y5 ≧ 0, y3 + y4 + y5 <x5 + x6 + x7 + x8. Further, the portion surrounded by <> may be random addition or block addition, the portion surrounded by [] indicates random addition, and the portion surrounded by () indicates block addition. R ⁵ is a linear or branched alkyl group or alkenyl group having 5 to 18 carbon atoms, and z is a number of 1 to 20 indicating the average number of moles of oxyethylene group added. ]

In the general formula (I), R ¹ is a linear or branched alkyl group or alkenyl group having 4 to 14 carbon atoms, and more preferably R ¹ is a straight chain or branched chain group having 6 to 10 carbon atoms. More preferably, R ¹ has 8 to 14 carbon atoms. n represents the average addition mole number of the oxyethylene group, m represents the average addition mole number of the oxypropylene group, and 0 ≦ n ≦ 20 and 0 <m ≦ 20. Such nonionic surfactants are preferably those having an HLB of 4.3 to 8.2, more preferably 5 to 7.9, as determined by the Davis method. When the HLB is in this range, the balance between permeability and emulsification is good, and good degreasing properties are obtained.

In the nonionic surfactant represented by the general formula (I), the addition form of oxyethylene and oxypropylene may be block or random, and in the case of block, the positions of oxyethylene and oxypropylene may be reversed. However, the block addition to R ¹ O in the order of oxypropylene-oxyethylene is more preferable.

  In the compound represented by the general formula (I), preferred average addition moles of the oxyethylene group and the oxypropylene group are 0 ≦ n <8 and 0 <m <5, and 3 <n <8. Is more preferable.

In the general formulas (II) to (IV), R ² , R ³ and R ⁴ are each a straight or branched alkyl group or alkenyl group having 6 to 24 carbon atoms, preferably carbon. A linear or branched alkyl group or alkenyl group having 8 to 20 carbon atoms, more preferably a linear or branched alkyl group or alkenyl group having 10 to 18 carbon atoms, and particularly preferably 10 to 16 carbon atoms. A linear or branched alkyl group or alkenyl group.

  In the compound represented by the general formula (II), x1 and x2 indicating the average added mole number of ethylene oxide are each 1 or more, and from the viewpoint of compatibility with water, the sum of x1 and x2 is 4 or more. Is the number of The washing performance does not change even if the sum of x1 and x2 exceeds 20, but from the viewpoint of wastewater treatment and foaming suppression, the sum of x1 and x2 is preferably a number of 20 or less, more preferably 6 to A number of 15. Further, the average addition mole number y1 of propylene oxide of the compound represented by the general formula (II) is larger than 0 from the viewpoint of detergency, biodegradability, etc., and x1 and x2 are the average addition mole numbers of ethylene oxide. The number is smaller than the sum of the numbers, preferably 0.5 to 6, more preferably 1 to 5.

  In the compound represented by the general formula (III), x3 and x4 indicating the average added mole number of ethylene oxide are each 1 or more, and the sum of x3 and x4 is 4 or more from the viewpoint of compatibility with water. Is the number of In addition, the washing performance does not change even if the sum of x3 and x4 exceeds 20, but from the viewpoint of wastewater treatment and foaming suppression, the sum of x3 and x4 is preferably a number of 20 or less, more preferably 6 to A number of 15. In addition, the average addition mole number y2 of propylene oxide of the compound represented by the general formula (III) is larger than 0 from the viewpoint of detergency, biodegradability, and the like, and x3 and x4 which are average addition mole numbers of ethylene oxide The number is smaller than the sum of the numbers, preferably 0.5 to 6, more preferably 1 to 5.

  In the compound represented by the general formula (IV), x5 and x8 indicating the average added mole number of ethylene oxide are each 1 or more, and the sum of x6 and x7 is 1 or more and is compatible with water. In view of the above, the sum of x5, x6, x7, and x8 is a number of 4 or more. Although the washing performance does not change even if the sum of x5, x6, x7 and x8 exceeds 20, the sum of x5, x6, x7 and x8 is preferably a number of 20 or less from the viewpoint of wastewater treatment and foam suppression. And more preferably a number of 6-15. Further, the average addition mole number y3, y4, y5 of propylene oxide of the compound represented by the general formula (IV) is 0 or more, and y3 + y5 ≧ 0.1, preferably y3 + y5 ≧ 1. The sum of y3, y4 and y5 is smaller than the sum of x5, x6, x7 and x8, which is the average added mole number of ethylene oxide, from the viewpoint of detergency, biodegradability, etc., preferably 0.5-6, More preferably, it is a number of 1-5.

In the general formula (V), R ⁵ is preferably a linear or branched alkyl group or alkenyl group having 6 to 12 carbon atoms, and further 6 to 10 carbon atoms, and R ⁵ is a linear chain having 6 to 8 carbon atoms. In the case of a branched alkyl group or alkenyl group, the average addition mole number z of the oxyethylene group is 1 to 10, and R ⁵ is a linear or branched alkyl group or alkenyl group having 9 to 10 carbon atoms. The average added mole number z of oxyethylene groups is 4-10. Even more preferably, when R ⁵ is a linear or branched alkyl or alkenyl group having 6 to 7 carbon atoms, z is 2 to 8, and R ⁵ is a linear or branched chain having 8 to 10 carbon atoms. In the case of the alkyl group or alkenyl group, z is 4-8.

  In addition, among the component (d), an alkylene oxide adduct of alkyl (having 5 to 12 carbon atoms in the alkyl group) phenol is also preferably obtained by adding an alkylene oxide so that the HLB is in the above range. The alkylene oxide is preferably ethylene oxide or propylene oxide, and particularly preferably contains ethylene oxide. The average added mole number of ethylene oxide is preferably 6-15.

[Optional ingredients]
The steel strip cleaning composition of the present invention can contain an alkali agent other than the component (a) as required, for example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, Examples thereof include phosphates such as trisodium phosphate, carbonates such as disodium carbonate, sodium hydrogencarbonate and dipotassium carbonate, and borate salts such as sodium borate. Two or more alkali agents may be combined. Sodium hydroxide and potassium hydroxide are preferable, and sodium hydroxide is more preferable.

  The steel strip cleaning composition of the present invention can contain a chelating agent other than the component (b) as long as the effects of the present invention are not impaired.

  The chelating agent is considered to play a role of enhancing the cleaning effect by binding to and removing metal atoms in the soil.

  In the steel strip cleaning composition of the present invention, the weight ratio (a) / (b) of the component (a) and the component (b) is from the viewpoint of achieving both cleanability and reducing the adhesion of the steel strip after annealing. The ratio is preferably 4/1 to 70/1, more preferably 4/1 to 40/1, and still more preferably 4/1 to 8/1.

  In the steel strip cleaning composition of the present invention, the content of the component (a) and the component (b) is the sum of both, and the cleaning property, the adhesion reduction of the steel strip after annealing, and the stability of the composition. From the standpoint, it is preferably 0.1 to 26% by weight, more preferably 0.5 to 24% by weight, and still more preferably 1 to 24% by weight.

  In the steel strip cleaning composition of the present invention, the weight ratio (a) / (c) of the component (a) to the component (c) is preferably 60/1 from the viewpoint of securing the stability of the composition. To 5/1, more preferably 50/1 to 7/1, and still more preferably 40/1 to 10/1.

  In the steel strip cleaning composition of the present invention, the content of the component (d) is 0.01 to 30% from the viewpoint of improving the cleaning property and suppressing foaming of the composition to obtain good usability. % Is preferable, 0.01 to 10% by weight is more preferable, and 0.02 to 5% by weight is particularly preferable.

  The steel strip cleaning composition of the present invention is used as it is or diluted with water or the like, but the concentration of the total amount of (a) and (b) in the composition (stock solution or diluted solution) at the time of use. Is different depending on the type of object to be cleaned and the type of dirt, but is preferably 0.1 to 10% by weight from the viewpoint of achieving both improvement in the cleaning property of the steel strip and reduction in the degree of adhesion of the steel strip after annealing. -7 wt% is more preferred, 0.5-5 wt% is more preferred, 0.5-4 wt% is even more preferred, and 1-3 wt% is even more preferred. If it is this range, the washing | cleaning property and the adhesiveness reduction effect of the steel strip after annealing will become favorable, and equipment corrosion can also be prevented.

  The steel strip cleaning composition of the present invention is a one-component composition containing components (a) and (b) and other components, particularly component (a) and component (b), and other It preferably consists of an aqueous solution containing the components.

  The steel strip cleaning composition of the present invention is preferably in the state of an aqueous solution at least at 40 ° C., and further at 40 to 50 ° C., from the viewpoint of achieving both improved cleaning properties and reduced adhesion of the steel strip. The steel strip cleaning composition of the present invention can be produced by mixing each component at a temperature of 50 ° C. or higher and stored at 50 ° C. or higher. In the presence of component (c), the total amount of component (a) and component (b) is 26% by weight or less, and further 24% by weight or less. It can be obtained as a composition. Here, an aqueous solution is a solution using water as a solvent, and a solution is a mixture in which one or more substances are dissolved in another substance in a uniform liquid state, like a suspension. It does not include those in which colloidal particles are dispersed in a solvent.

[Method of manufacturing steel strip]
A preferred method for producing a steel strip using the steel strip cleaning composition of the present invention will be described.

  Usually, the steel strip is manufactured through processes such as a cold rolling process, a cleaning process, a batch annealing process, a plating process, and a chemical conversion treatment process. Among these, the cleaning process generally includes a process of preliminary cleaning (immersion cleaning / spray cleaning) → electrolytic cleaning → brush cleaning → rinsing. In the cleaning process, the steel strip cleaning composition is added in the case of a one-component cleaning agent by adding water and a stock solution (one-component cleaning agent) to a cleaning tank and mixing and diluting it. Concentration management is performed with an alkali concentration in the case of a one-component detergent. The additive is used separately from the alkaline agent and added to the washing tank. The alkali agent is controlled at the alkali concentration, and the additive is mainly controlled at the nonionic surfactant concentration. Washing is performed in a temperature range of 40 to 90 ° C. In the case of a general cleaning line, the cleaning time is 0.5-5 seconds for immersion cleaning, 0.5-5 seconds for spray cleaning, 0.5-5 seconds for electrolytic cleaning, 0.5-5 seconds for brush cleaning, and rinse 0. .5 to 5 seconds. The steel strip cleaning composition of the present invention can also be used in such a normal cleaning process.

  The annealing process is performed by an annealing method somewhat different depending on the purpose. Generally, this is called complete annealing. The steel strip is put in an annealing furnace, heated to 800 ° C. to 900 ° C. and held for a certain period of time until about 400 ° C. After cooling slowly in the furnace, pull it out and air-cool.

  Since the surface of a cold-rolled steel strip is extremely smooth, the surface of the steel strip is very likely to be welded (adhesion = seizure) when annealed at a high temperature. When annealing cold-rolled steel strips at high temperatures in batch mode, if silicon is electrodeposited on the steel strip surface by electrolytic cleaning of the steel strip in a silicate solution before annealing, the contact area between the steel strips is reduced. Therefore, it is considered that welding (adhesion = burn-in) can be prevented. The steel strip cleaning composition of the present invention can further increase the adhesion reduction effect of electrodeposited silicon after electrolytic cleaning of the steel strip by adding a certain amount of gluconic acid and / or its salt to the silicate. .

  The steel strip cleaning composition and the steel strip manufacturing method of the present invention are particularly preferably used in batch coil annealing of tight coils.

[I] Preparation of cleaning composition for steel strip (I-1) Examples 1 to 15 and Comparative Examples 1 to 7
The component (b) in Table 1 is dissolved in water at room temperature (25 ° C.). Next, component (c) and component (d) in Table 1 are added and mixed (stirred) and dissolved at room temperature. Furthermore, component (a) (orthosilicate sodium; 30% solid content aqueous solution, Nippon Kagaku Kogyo Co., Ltd.) or sodium hydroxide dissolved in 50 to 80 ° C. (without crystal precipitation) was added and mixed ( A clear one-component steel strip cleaning composition was prepared by stirring). However, Comparative Example 6 was in a state where two layers were separated after stirring.

(I-2) Comparative Example 8
An aqueous solution (40% solid content) of sodium polyacrylate is mixed with the component (b) dissolved in water and stirred, and then sodium hydroxide is added so that the concentration in the composition is 40% by weight. The mixture is mixed to form a suspension containing component (b), sodium polyacrylate, and sodium hydroxide, and component (d) is further stirred and mixed using a homogenizer (rotation speed: 12000 rpm) while being sheared. A one-pack type steel strip cleaning composition was prepared.

[II] Evaluation After putting 1000 g of the steel band cleaning composition of Tables 1 and 2 into a polystyrene container and storing it at 40 ° C. for 2 months, 20 g of the lower layer of the composition was sampled from the lower part of the container, The required amount was collected from the sample and diluted 3 to 30 times with water, and then a steel strip cleaning test (degreasing property) and an adhesion test were performed by the following methods. Moreover, the state of the composition after the storage was observed to evaluate the storage stability. The results are shown in Tables 1 and 2.

(II-1) Evaluation of Detergency (Degreasing) (1) Cleaning Test Procedure Cleaning solution obtained by diluting the steel strip cleaning compositions in Tables 1 and 2 at the dilution ratios in Tables 1 and 2 (hereinafter referred to as test cleaning solutions) The steel strip is immersed in a test cleaning solution at 80 ° C. or 40 ° C. for 1 second, and then the steel charging position is switched from negative to positive once every 0.5 seconds at a current density of 5 A / dm ² . Thereafter, it was rinsed with water and dried.

(2) Steel strip A cold rolled steel strip having an average oil content of 140 mg / m ² was cut into a size of 25 mm × 50 mm (hereinafter referred to as a steel strip).

(3) Measuring method of residual oil adhesion amount The detergency was evaluated by the residual oil adhesion amount on the surface of the steel strip after the cleaning test. The amount of oil remaining on the surface of the steel strip was all measured using a metal plate attached oil amount measuring device (EMIA-111 / Horiba Seisakusho). The measured value is an average value of five measurements. Detergency is an evaluation of degreasing properties, and the criterion is that the amount of residual adhered oil is 10 mg / m ² or more is poor (x), 3 mg / m ² or more and less than 10 mg / m ² is good (◯), 3 mg / m Less than ² was considered excellent (優).

(II-2) Evaluation of adhesion The same steel strip used for cleaning was cut into a size of 20 mm × 50 mm (hereinafter referred to as a steel strip). This steel strip was first cleaned by immersion in a solvent (n-hexane, at room temperature for 10 seconds), and then electrolytically cleaned based on the cleaning test procedure performed in the evaluation of cleaning properties. The amount of electrodeposited Si of the steel strip after electrolytic cleaning and the adhesion strength of the steel strip were measured.

(1) in the electrodeposition Si amount measured fluorescent X-ray analyzer, the intensity of Si of the steel strip after cleaning was measured to obtain the Si deposition amount of the steel strip 1 m ² per using a pre-prepared calibration curve It was.

(2) As 20 mm × 30 mm steel strip after measurement cleaning the adhesion strength overlap, putting spacers for each pair, then set on a holder as shown in FIG. 1, the surface pressure P in the stack 50 kg / cm ² After pressurizing to become, it was charged in an annealing furnace and annealed. After completion of annealing (after completion of cooling), as shown in FIG. 2, the upper and lower steel strips were pulled in opposite directions, and the peel strength T was measured. The annealing conditions are as follows.
<Annealing conditions>
Annealing atmosphere: N ₂ gas + H ₂ gas (H ₂ gas: 5% by volume)
Annealing temperature: 700 ° C
Temperature rising time: 2 hours Annealing time: 1 hour Cooling time: 10 hours

(III) Evaluation of Storage Stability The appearance and the like of the composition after observing the steel strip cleaning compositions of Tables 1 and 2 (composition before dilution) at 40 ° C. for 2 months were observed. “None” indicates no change in appearance and no phase separation, and “Yes” indicates that phase separation occurs. A comparison was made. Further, “None” indicates that neither thickening nor solidification occurs, and “Yes” indicates that thickening and / or solidification occurs.

In the table, the symbols mean the following (hereinafter, EO is ethylene oxide, PO is propylene oxide, and mole is an average number).
D-1: nonionic surfactant obtained in Synthesis Example 1 below d-2: dodecanol EO 7 mol PO 1.5 mol EO 7 mol block adduct d-3: 2-ethylhexanol EO 4 mol adduct d-4: secondary dodecanol EO 12 mol PO3 mol block adduct d-5: octylphenol EO 10 mol adduct

<Synthesis Example 1>
An ethoxylate compound (trade name “Softanol”) obtained by adding 3 moles of ethylene oxide to a secondary alcohol with an average carbon number of 12 in a 5-liter rotary stirring autoclave equipped with two measuring tanks for ethylene oxide and propylene oxide. 30 ”(manufactured by Nippon Shokubai Co., Ltd.) and 3.0 g of potassium hydroxide were charged. After nitrogen substitution, the temperature was raised to 110 ° C. and dehydration was performed at 5.33 kPa for 1 hour. Next, the temperature was raised to 150 ° C., 267 g of ethylene oxide was introduced into the autoclave at a pressure of 343 kPa, reacted until the pressure decreased and became constant, and then cooled to 120 ° C. to 352 g of propylene oxide in the autoclave. It was introduced at a pressure of 343 kPa, and the reaction was continued until the pressure dropped and became constant as in the case of ethylene oxide. Thereafter, the temperature was raised again to 150 ° C., 668 g of ethylene oxide was introduced, and the reaction was continued until the pressure decreased and became constant. After completion of the reaction, a sample synthesized at a reduced temperature was taken out, and the catalyst was neutralized with acetic acid to obtain about 2.3 kg of a nonionic surfactant (average molecular weight: 760). The obtained nonionic surfactant is represented by the general formula R ² -O- (EO) _x1- (PO) _y1- (EO) _x2 -H, where R ² is a secondary alkyl group having 12 carbon atoms in total, and x1 is 5. It was a compound in which x2 was 5 and y1 was 2.

  In addition, in the cleaning compositions for steel strips of Examples 1 to 3 and 5 to 13, no phase separation, thickening, and solidification occurred in the storage stability evaluation.

In an Example and a comparative example, it is the schematic which shows the installation condition of the steel strip piece when annealing. It is the schematic which shows the direction which measures the peeling strength of the steel strip after annealing in an Example and a comparative example.

Claims (6)

  A cleaning composition for a batch-type annealed steel strip containing silicate (a), gluconic acid and / or a salt thereof (b), and water.   The cleaning composition for a batch-type annealed steel strip according to claim 1, wherein the weight ratio of (a) and (b) is (a) / (b) = 4/1 to 70/1.   The cleaning composition for batch-type annealed steel strips according to claim 1 or 2, wherein (a) and (b) are contained in a total amount of 0.1 to 26% by weight. The batch-type annealed steel strip according to any one of claims 1 to 3, further comprising at least one compound (c) selected from compounds represented by the following general formulas (1) to (3): Cleaning composition.
R ¹ —X— (CH ₂ ) _m COOM ¹ (1)
R ² -COOM ² (2)
R ³ -COOM ³ (3)
[Wherein, R ¹ represents a saturated or unsaturated linear or branched aliphatic hydrocarbon group having 4 to 22 carbon atoms or an aromatic hydrocarbon group having 5 to 18 carbon atoms, and X represents a group> NH, > N (CH ₂ ) _n COOM ¹ or> CHCOOM ¹ R ² represents a saturated or unsaturated linear aliphatic hydrocarbon group having 3 to 22 carbon atoms or an aromatic hydrocarbon group having 5 to 18 carbon atoms. R ³ represents a saturated or unsaturated branched aliphatic hydrocarbon group having 4 to 22 carbon atoms. M ¹ , M ² and M ³ each represent a hydrogen atom, an alkali metal, an aliphatic amine having 1 to 4 carbon atoms, ammonia or an alkanolamine, and m and n each represent an integer of 1 to 3. ]   Further, it contains a nonionic surfactant (d) that is at least one selected from alkylene oxide adducts of alcohols having 4 to 24 carbon atoms and alkylene oxide adducts of alkyl (C5 to C12 alkyl groups) phenol. The cleaning composition for batch-type annealed steel strips according to any one of claims 1 to 4.   It is a steel strip manufacturing method which has a batch type annealing process after an electrolytic cleaning process, Comprising: Steel strip manufacture which uses the cleaning composition for batch type annealing steel strips in any one of Claims 1-5 in an electrolytic cleaning process Method.

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