JP3199824B2 - Cleaning solution for tinplate and cleaning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to tinplate ("tin-plated steel").
. The same shall apply hereinafter) plates, strips and their molded products, such as cans (these are generally referred to as "tinplates").
The present invention relates to a tinting material cleaning liquid and a cleaning method applied for cleaning the surface of a tin plate. In particular, the present invention draws and irons tinplate (Drawing & Ironin).
g) It is suitable for cleaning tinplate DI cans formed by the above. More specifically, the present invention is applied to the surface of a tinplate material, and from the surface, an organic substance such as oil or lubricant,
In addition to removing inorganic substances such as abrasion powder to give a surface condition with excellent chemical conversion treatment, sludge precipitation is extremely unlikely to occur due to the insoluble precipitate of tin eluted from the tinplate surface into the cleaning solution by washing. The present invention relates to a cleaning solution and a cleaning method for a tinting material.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 59-2752 and Japanese Patent Application Laid-Open No. 3-59993 relate to the prior art of a cleaning solution for a tinting material.
And Japanese Patent Application Laid-Open No. 3-59994. The alkali cleaning solution of JP-B-59-2752 uses an alkali metal silicate and an alkali metal salt and an alkali metal bicarbonate in a weight ratio of 1.5 times or less and a surfactant 0.4 times by weight thereof. The alkaline component to be referred to as a builder is specified as described above so that the tin-plated surface is not excessively dissolved when the line is stopped due to a trouble in the degreasing treatment line.

The alkaline cleaning solution disclosed in Japanese Patent Application Laid-Open No. 3-59993 is intended to prevent excessive dissolution of the tin-plated surface in the same manner as in the above-mentioned publication, and to contain 1.5 to 10 g / l of an alkali metal or ammonium salt of orthophosphoric acid and nitrous acid. 0.5 to 2 g / l of an alkali metal salt is used in a molar ratio of the former to the latter of 1: 1 to 3.
It is an aqueous solution containing a ratio of 86: 1 and adjusted to pH 9 to 11 with an alkali metal carbonate.

The alkali cleaning solution disclosed in Japanese Patent Application Laid-Open No. 3-59994 also aims to prevent the tin-plated surface from being excessively dissolved, and is intended to prevent the dissolution of alkali metal salts of orthophosphoric acid or ammonium alkaline earth metal oxides, hydroxides, chlorides, etc. P-containing at least 0.005 g / l of at least one selected from the group consisting of bromide, iodide, carbonate, nitrate, sulfate and phosphate, and a surfactant, and not containing an organic acid or a salt thereof;
It is an alkaline aqueous solution having H9 to H13.

[0005]

The cleaning of tinplate is often carried out by spraying. For example, the surface treatment equipment for tinplate DI cans is usually called a washer, and the formed DI cans are continuously treated with a cleaning liquid or a chemical liquid in an inverted state. Existing washers consist of six steps: pre-washing, washing, rinsing, chemical conversion, rinsing, and deionized rinsing, all of which are performed by spraying. The alkaline cleaning solution is sprayed into a number of DI cans in the pre-cleaning and cleaning steps described above, collected in a tank and sprayed again.

[0006] When the alkaline cleaning liquid of JP-B-59-2752 is actually used for a washer, it is possible to perform good cleaning at an early stage, but silicate is gradually precipitated from the cleaning liquid. These precipitates (solid matter generally called sludge) clogged the pipes and nozzles of the spray device, and it became impossible to wash well.

The alkali cleaning solution disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 3-59993 is described as having an increased metal solubility in the presence of a condensed phosphate, resulting in poor anticorrosion properties in both the unpainted and tinted tinplate. Since the condensed phosphate is removed from the washing solution, the dissolution of tin is suppressed, but the tin which is slightly dissolved precipitates as tin phosphate or the like to form sludge, which causes the same problem.

The alkali cleaning solution disclosed in Japanese Patent Application Laid-Open No. 3-59994 can be effectively cleaned at the initial stage when it is actually used, but tin gradually eluting from the tinting material contains phosphoric acid in the cleaning solution. Alternatively, it reacts with carbonic acid to precipitate and precipitate phosphates and carbonates, and these become sludge.

[0009] As described above, part of the sludge generated by the continuous washing precipitates in the liquid tank, and part of the sludge clogs the pipes and nozzles of the spray device when circulating through the piping system. If the pipes and nozzles are clogged, the spray amount to each DI can is reduced, and the contact of the liquid becomes uneven, so that good cleaning cannot be performed.

Therefore, when a conventional alkaline cleaning liquid is used, it is necessary to periodically and frequently clean the pipes and nozzles of the spray device. In recent years, it has been an important task to improve the productivity of tinplate cleaning, and there is a demand for a cleaning liquid that reduces the load of cleaning, that is, generates no sludge in the liquid even when used continuously.

[0011] In addition, a small amount of industrially used alkaline cleaning liquid is periodically or continuously discarded by a method called auto drain, and is replaced with a new cleaning liquid.
These discarded cleaning liquids are discharged through a wastewater treatment process. Although the above-mentioned conventional alkaline cleaning liquid does not need to be subjected to particularly advanced wastewater treatment, solid matter (also generally referred to as “sludge” due to wastewater treatment, but in the present application, to be distinguished from the aforementioned sludge, Called "wastewater treatment sludge").

The conventional alkaline cleaning solution has a high alkali concentration during cleaning, and thus has a problem in that the processing amount of the entire sludge after the waste liquid processing increases. At present, this sludge is discarded as industrial waste, but reduction in cost and environmental protection is desired. In recent years, the regulation value of effluent water has become strict due to environmental problems, and reducing the wastewater treatment load is a major issue.

[0013]

In order to solve the above-mentioned conventional problems, an alkali metal hydroxide, an inorganic alkali metal salt or ammonium phosphate, an alkali metal borate, an alkali metal silicate, and an alkali carbonate are used. 0.5 to 10.0 g / l of one or more alkali builders selected from metal salts or ammonium salts, and from hydroxylalkyl diphosphonic acid, aminotrialkyl phosphonic acid, and alkali metal salts and ammonium salts thereof 0.05 to 1.0 g / l of one or more selected chelating agents and 0.05 to 1.0 g of a surfactant
The present inventors have found a tincture cleaning solution comprising 2.0 g / l and water and having a pH of 8 to 11, and completed the present invention.

That is, the cleaning liquid for a tinting material of the present invention removes organic substances such as oil and lubricant and inorganic substances such as abrasion powder from the surface of a plate, a strip, and a molded article of the tinting material, for example, a can. The surface condition excellent in the processability is provided, and the amount of the sludge precipitated due to the tin eluted in the cleaning liquid and the hardness component contained in the water used in the cleaning liquid is extremely small.

The cleaning solution of the present invention is preferably used for cleaning DI cans, and includes alkali metal hydroxides, inorganic alkali metal salts or ammonium phosphates, alkali metal borates, alkali metal silicates, and the like. And one or two or more alkali builders selected from alkali metal carbonates or ammonium carbonates in an amount of 0.5 to 10.0 g /
and 0.05 to 1.0 g / l of one or more chelating agents selected from hydroxylalkyldiphosphonic acid, aminotrialkylphosphonic acid, and alkali metal salts and ammonium salts thereof, and a surfactant 0.
0.5 to 2.0 g / l and water and the pH is 8 to 1
The tinting material cleaning liquid, which is 1, is sprayed from a storage tank through a nozzle to a tinting material to be cleaned through a nozzle, returned to the tinting liquid storage tank, and sprayed again to generate sludge of tin and hard water components. A number of DI cans are continuously washed without the need.

That is, this tinting material cleaning method removes organic substances such as oils and lubricants and inorganic substances such as abrasion powder from the surface of the DI can when the DI can is washed with a washer, and provides a surface condition excellent in chemical conversion treatment. And long-term continuous cleaning is performed without generating sludge generated by tin eluted in the cleaning liquid and a hardness component contained in water used in the cleaning liquid. The presence or absence of the generation of sludge is determined by collecting the liquid from the alkaline cleaning liquid storage tank into a transparent container and visually checking whether the liquid is transparent. For continuous washing, washing temperature: room temperature to 80 ° C,
Spray time: 2 to 60 seconds / can: liquid renewal / disposal: 0.0
Sludge-free processing is possible in continuous processing under general processing conditions of 4 to 0.08% / 1000 cans.

Hereinafter, the composition of the alkaline cleaning solution of the present invention and the cleaning process will be described in detail. In the components of the alkaline cleaning solution of the present invention, an alkali metal hydroxide, an inorganic metal salt or ammonium phosphate, an alkali metal borate,
The content of one or more alkali builders selected from alkali metal silicates and alkali metal carbonates or ammonium salts (described in Examples as component A) is 0.05 to 10.0 g / l. .

The content of one or more compounds selected from the group consisting of hydroxylalkyldiphosphonic acid, aminotrialkylphosphonic acid, and alkali metal salts and ammonium salts of these compounds (described as component B) is as follows: It is 0.05 to 1.0 g / l.

Further, the content of the surfactant (described in the examples as component C) is 0.05 to 2.0 g / l. The balance of the above components is water, which is industrial water or city water. The pH of the tinting material cleaning solution is 8 to 11.

The alkali metal salt of the alkali builder includes potassium or sodium hydroxide, carbonate, borate and inorganic phosphate, for example, potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, hydrogen carbonate. Potassium, borax, trisodium phosphate and the like. One or two or more of these are contained, and the concentration is selected so as to provide a cleaning power (etching property) suitable for the state of the surface of the tinplate. Generally, the content of the alkali builder is 0.5 to 10.0 g / l, preferably in the range of 1.0 to 5.0 g / l. If it is less than 0.5 g / l, it cannot be cleaned well due to insufficient etching. 1
Even if the amount exceeds 0.0 g / l, it is possible to wash well, but wastewater treatment sludge generated by wastewater treatment increases.

Hydroxylalkyldiphosphonic acid, aminotrialkylphosphonic acid, and alkali metal salts and ammonium metal salts thereof are added to stably present tin ions from a tinplate in the washing solution. That is, when the tinplate is continuously washed, tin ions accumulate in the solution and react with phosphoric acid, silicic acid, carbonic acid, etc. to generate sludge. It suppresses the generation of sludge such as tin phosphate in the inside. By suppressing the generation of sludge, the cleaning load on the pipes and nozzles of the spray device is greatly reduced.

On the other hand, calcium and magnesium ions, which are contained as hard components in city water, do not accumulate in the washing solution as described above and do not hinder continuous processing, but they are simultaneously chelated by hydroxylalkyldiphosphonic acid or the like. It is not mixed into sludge as calcium carbonate or the like.

The hydroxyalkyldiphosphonic acid is represented by the following formula: 1-hydroxyethylidene-
1,1-diphosphonic acid is exemplified.

[0024]

Embedded image

The aminotrialkylphosphonic acid includes aminotrimethylenephosphonic acid. Examples of the condensed phosphoric acid include pyrophosphoric acid, tripolyphosphoric acid, and tetrapolyphosphoric acid. Hydroxylalkyldiphosphonic acid, aminotrialkylphosphonic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid and condensed phosphoric acid can be used in the washing solution with the acid or its alkali metal salt and ammonium salt. The content of one or more of these compounds is from 0.05 to 1.
0 g / l, preferably in the range of 0.1 to 0.5 g / l. If it is less than 0.05 g / l, sludge tends to be generated in the cleaning solution due to insufficient chelating power. 1.0g /
Although there is no particular problem if it exceeds l, the cost increases and there is an economical problem.

[0026]

In areas where wastewater regulations are particularly strict, phosphorus- and nitrogen-free detergents are useful.
In the present invention, if the alkali builder is selected from hydroxides, carbonates or borates, and if a hydroxylalkyldiphosphonic acid or an aminotrialkyldiphosphonic acid is selected, the composition may be free of phosphorus and nitrogen. It is possible. Note that phosphorus is contained in hydroxylalkyldiphosphonic acid and aminotrialkylsulfonic acid,
As mentioned earlier, this is not a problem as it can be easily settled with slaked lime.

Further, the concentration of the alkali salt in the cleaning solution according to the present invention is lower than that shown in the conventional experimental example, and can be 4 g / l or less. This is because hydroxylalkyl diphosphonic acid and the like have a cleaning effect, and the wastewater treatment sludge generated in the wastewater treatment step can be reduced by reducing the amount of alkali builder.

The surfactant is selected from an anionic surfactant and a nonionic surfactant. For example, nonionic surfactants include hydrocarbon derivatives, abietic acid derivatives,
Examples include primary ethoxylated alcohols and modified polyethoxylated alcohols, each containing one or two or more. The content is in the range of 0.05 to 2.0 g / l, preferably 0.2 to 1.0 g / l. When the content is less than 0.05 g / l, the organic matter on the surface of the tinplate cannot be completely removed. On the other hand, when the content exceeds 2.0 g / l, there is no particular problem in detergency. There's a problem.

The pH of the washing solution is in the range of 8 to 11, preferably 9 to 10. If the pH is less than 8, the etching power is low and it is difficult to clean well, and sludge is easily generated. If the pH is 11 or more, the etching power becomes too strong, and the appearance is unfavorably deteriorated. Adjustment of pH is performed by using common alkali or acid, that is, sodium hydroxide,
Potassium hydroxide, sulfuric acid, phosphoric acid, or the like may be used, and is not particularly limited.

The processing temperature of the cleaning solution of the present invention is from room temperature to 80 ° C.
Although it is possible to use it, it is usually preferable to use it after heating to 40 to 60 ° C. The processing time is 2 to 60 seconds, but if it is less than 2 seconds, it cannot be sufficiently washed. Even if the treatment is carried out for more than 60 seconds, no improvement in the cleaning property is observed, so that the treatment time is suitably in the range of 2 to 60 seconds. The treatment method can be either an immersion method or a spray method, but as described above, the present invention exerts particularly excellent effects when used in a spray device.

In the wastewater treatment of the cleaning solution for the tinplate,
Metal ions are dissociated from the chelate compound on the acidic pH side, and then solid-liquid separation is performed by adding calcium hydroxide and a polymer coagulant to obtain wastewater treatment sludge. The cleaning solution according to the present invention has a low alkali concentration, so that a small amount of sludge is discarded. In addition, hydroxylalkyldisulfonic acid and aminotrialkylsulfonic acid have excellent sedimentation properties with calcium hydroxide and a polymer flocculant, so that wastewater treatment efficiency is also good.

[0033]

As described above, tin ions accumulate during washing of the tinplate, and the concentration of tin ions in the cleaning solution when sludge is generated is estimated to be 0.01 to 0.1 g / l. The sludge generated by the sedimentation has a strong adhesive property, and adheres to the inside of the nozzle or the pipe to hinder the cleaning. As a means to prevent such adhesion, measures to suppress the dissolution of the tin-plated surface and prevent the concentration of tin ions are effective.
In the case of a large amount of washing, there is a limit in the countermeasures, and therefore, in the present invention, components to be added other than the alkali builder and the surfactant are devised as described above. As a result, by cleaning the surface of the tinplate, strip and the molded product with the cleaning liquid according to the present invention, organic and inorganic substances are removed from the surface of the tinplate material, and a surface state excellent in chemical conversion treatment is provided, and In addition, the amount of sludge deposited due to tin eluted in the cleaning liquid is extremely small. The degreasing property was evaluated from the amount of oil remaining on the surface. The can after the treatment in the step [1] is ultrasonically cleaned using carbon tetrachloride, and the oil eluted into the carbon tetrachloride from the surface of the can is measured with an oil concentration measuring device (POC-100 manufactured by Shimadzu Corporation).
And converted to the oil content remaining per unit surface area of the can. Generally, it is good if it is 2 mg / m 2 or less.

[0034]

EXAMPLES Several examples of the cleaning solution of the present invention will be described below, and its usefulness will be shown in comparison with comparative examples. (1) Test material Unwashed can (66m) made by DI processing tin plated steel sheet
(mφ × 124 mmh) was used as a test material, and was washed with an existing washer.

(2) Processing Step The processing step followed the following step [1] or [2]. Process [1] Washing Washing (spray for 10 seconds) Deionizing water washing (spray for 10 seconds) Drying (180 ° C, hot air)

Step [2] Washing Water washing (10 seconds spray) Chemical conversion treatment (30 seconds spray) Treatment agent: registered trademark Parphos K3482, manufactured by Nippon Parkerizing Co., Ltd. Concentration: 3% Temperature: 60 ° C. Water washing (10 seconds spray) Deionization Rinse (spray for 10 seconds) Dry (180 ° C, hot air)

(3) Accuracy test method [Water wettability] After the deionized water washing in step [1] is completed,
It was left for 0 seconds, and the water wet area at that time was evaluated in%. Generally, 90% or more is good.

[Defatting property] The degreasing property was evaluated based on the amount of oil remaining on the surface. The can treated after the treatment in step [1] was ultrasonically cleaned with carbon tetrachloride, and the can was treated with carbon tetrachloride from the surface of the can. The eluted oil was measured using an oil concentration measuring device (POC-1 manufactured by Shimadzu Corporation).
00) and converted to the oil content remaining per unit surface of the can. Generally, it is good if it is ² mg / m ² or less.

[Corrosion Resistance] The corrosion resistance of the can after the treatment in step [2] is determined by the degree of iron exposure (IE
V). The measurement of IEV was based on US Pat. No. 4,332,646. The lower the IEV value, the better the corrosion resistance.

[Coating Adhesion] The coating adhesion was measured by applying an epoxy urea-based coating for can to a coating thickness of 5 to 7 μm on the surface of the treated can in step [2], and baking at 215 ° C. for 4 minutes. The can was cut into a strip of 5 × 150 mm, and thermocompression-bonded with a polyamide-based film to obtain a test piece, which was peeled off by a 180 ° peel test method, and evaluated by the peel strength at that time.
Therefore, the higher the peel strength, the better the paint adhesion. Generally, a width of 1.5 kgf / 5 mm or more is good.

[Sludge generation in cleaning solution] The cleaning solutions used in Examples and Comparative Examples were prepared so as to contain no surfactant. 0.1 g of tin in these cleaning solutions
/ L (using stannic chloride and adjusting the pH with potassium hydroxide after the addition) and allowed to stand for one day. Then, the state of the liquid thereafter was observed. Those which are transparent and free from precipitation or the like are preferred.

[Wastewater treatment property] The wastewater treatment property was evaluated by the following method. The treatment liquid is diluted to 1/10, which is equivalent to the degree of dilution of the treatment liquid wastewater treatment in actual operation, and this liquid is diluted with sulfuric acid.
The pH was adjusted to 2.5. Next, an aqueous solution of aluminum sulfate was added so as to be 20 ppm as aluminum, and the pH was adjusted to 10 with calcium hydroxide.
10 ppm of a polymer flocculant was added thereto, and solid-liquid separation was performed. The remaining sludge (solid content) was dried at 110 ° C. for 24 hours, and the weight was measured after cooling. The wastewater treatment property was evaluated from this weight. That is, it is preferable that the amount of sludge generated is small.

Reference Example 1 Washing was performed at 50 ° C. for 30 seconds using the following washing solution 1. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. Further, sludge generation property and waste water treatment property of the cleaning liquid 1 were evaluated. Washing liquid 1 Sodium carbonate (A) 2.0 g / l Sodium hydrogen carbonate (A) 2.0 g / l Sodium tripolyphosphate (B) 0.4 g / l Nonylphenol EO 11 mol adduct (C) 0.2 g / l pH 9. 6 (adjusted with sodium hydroxide)

Example 1 Washing was performed at 50 ° C. for 30 seconds using a washing solution 2 shown below. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. Further, sludge generation property and waste water treatment property of the cleaning liquid 2 were evaluated. Washing liquid 2 Potassium carbonate (A) 1.0 g / l Potassium hydrogen carbonate (A) 2.0 g / l 1-hydroxyethylidene-1,1-diphosphonic acid (B) 0.2 g / l Higher alcohol EO-5 mol, PO -10 mol adduct (C) 0.3 g / l pH 9.6 (adjusted with sodium hydroxide)

Reference Example 2 Washing was performed at 50 ° C. for 30 seconds using a washing solution 3 shown below. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. Further, sludge generation property and wastewater treatment property of the cleaning liquid 3 were evaluated. Washing liquid 3 Sodium carbonate (A) 2.0 g / l Sodium hydrogen carbonate (A) 2.0 g / l Sodium ethylenediamine tetraacetate (B) 0.5 g / l Higher alcohol EO-5 mol, PO-10 mol adduct (C ) 0.2 g / l pH 10.0 (adjusted with sodium hydroxide)

Example 2 Washing was performed at 50 ° C. for 60 seconds using a washing solution 4 shown below. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. The cleaning liquid 4 was evaluated for sludge generation and wastewater treatment. Washing liquid 4 Sodium carbonate (A) 1.0 g / l Sodium bicarbonate (A) 2.0 g / l 1-hydroxyethylidene-1,1-diphosphonic acid (B) 0.3 g / l Nonylphenol EO 11 mol adduct (C) 0.2 g / l pH 8.7 (adjusted with sulfuric acid)

Example 3 Washing was carried out at 40 ° C. for 15 seconds using a washing solution 5 shown below. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. Further, sludge generation property and wastewater treatment property of the cleaning liquid 5 were evaluated. Washing liquid 5 Sodium hydroxide (A) 0.3 g / l Disodium hydrogen phosphate (A) 1.0 g / l 1-hydroxyethylidene-1,1-diphosphonic acid (B) 0.3 g / l Nonylphenol EO 11 mol adduct (C) 0.4 g / l pH 10.5 (adjusted with sodium hydroxide)

Example 4 Washing was performed at 60 ° C. for 60 seconds using a cleaning solution 6 shown below. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. Further, sludge generation property and waste water treatment property of the cleaning liquid 6 were evaluated. Washing liquid 6 Sodium carbonate (A) 1.0 g / l Sodium bicarbonate (A) 2.0 g / l Sodium tripolyphosphate (B) 0.1 g / l 1-hydroxyethylidene-1,1-diphosphonic acid (B) 0.1 g / l 3 g / l higher alcohol EO-5 mol, PO-10 mol adduct (C) 0.4 g / l pH 8.7 (adjusted with sulfuric acid)

Example 5 Washing was performed at 30 ° C. for 60 seconds using a cleaning solution 7 shown below. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. Further, sludge generation property and waste water treatment property of the cleaning liquid 7 were evaluated. Washing liquid 7 Sodium carbonate (A) 1.0 g / l Sodium hydrogen carbonate (A) 2.0 g / l Borax (A) 1.0 g / l 1-hydroxyethylidene-1,1-diphosphonic acid (B) 3 g / l higher alcohol EO-5 mol, PO-10 mol adduct (C) 0.4 g / l pH 10.2 (adjusted with sodium hydroxide)

Comparative Example 1 Washing was performed at 50 ° C. for 30 seconds using a washing liquid 8 shown below. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. Further, sludge generation property and wastewater treatment property of the cleaning liquid 8 were evaluated. Washing liquid 8 Sodium carbonate (A) 1.0 g / l Sodium hydrogen carbonate (A) 2.0 g / l Higher alcohol EO-5 mol, PO-10 mol adduct (C) 0.4 g / l pH 9.6 (water Adjusted with sodium oxide)

Comparative Example 2 Cleaning was performed at 50 ° C. for 30 seconds using the cleaning solution 9 shown below. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. Further, sludge generation property and waste water treatment property of the cleaning liquid 9 were evaluated. Washing liquid 9 Potassium carbonate (A) 1.0 g / l Potassium hydrogen carbonate (A) 2.0 g / l 1-hydroxyethylidene-1,1-diphosphonic acid (B) 0.2 g / l Higher alcohol EO-5 mol, PO -10 mol adduct (C) 0.4 g / l pH 7.5 (adjusted with sulfuric acid)

Comparative Example 3 Cleaning was performed at 60 ° C. for 60 seconds using the cleaning solution 10 shown below. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. Further, sludge generation property and wastewater treatment property of the cleaning liquid 10 were evaluated. Washing liquid 10 Sodium metasilicate (A) 2.5 g / l Sodium carbonate (A) 2.5 g / l Higher alcohol EO-5 mol, PO-10 mol adduct (C) 0.3 g / l Higher alcohol EO-5 mol , PO-10 mol adduct (C) 0.3 g / l pH 11.0 (adjusted with sodium hydroxide)

Comparative Example 4 Tinplate DI can detergent (registered trademark Fine Cleaner 4361A manufactured by Nippon Parkerizing Co., Ltd.) containing a commercially available alkali builder and a surfactant as active ingredients.
Washing was performed at 50 ° C. for 30 seconds using a% washing solution. And water wettability, degreasing property, corrosion resistance, and paint adhesion were evaluated. In addition, sludge generation property and wastewater treatment property of the cleaning liquid were evaluated.

[0054]

[Table 1]

[0055]

As is clear from Table 1 which summarizes the above-described Examples and Comparative Examples, the present invention is generally required for washing tin-plated DI cans, such as water wettability, degreasing property, corrosion resistance and adhesion. The cleaning performance is as good as before, and the sludge control and wastewater treatment are better than before.

Further, in the embodiment, an example of cleaning a DI can was described. However, it is clear that the same performance can be obtained for tinplates and strips as other molded products and materials. Therefore, the present invention has an extremely excellent effect of increasing the washing efficiency of tinplate and reducing the burden of wastewater treatment.

Claims (2)

(57) [Claims] 1. One or more selected from alkali metal hydroxides, alkali metal salts or ammonium inorganic phosphates, alkali metal borates, alkali metal silicates, and alkali metal salts or ammonium carbonates. And 0.5 to 10.0 g / l of an alkali builder, and 0.1 or more chelating agents selected from hydroxylalkyldiphosphonic acid, aminotrialkylphosphonic acid, and alkali metal salts and ammonium salts thereof. 0.05 to 1.0 g / l and 0.05 to
A cleaning solution for a tinplate, comprising 2.0 g / l, water and a pH of 8 to 11. 2. One or more selected from alkali metal hydroxides, alkali metal or ammonium inorganic phosphates, alkali metal borates, alkali metal silicates, and alkali metal or ammonium carbonates. 0.5 to 10.0 g / l of an alkali builder, and 0.05 or more of one or more chelating agents selected from hydroxylalkyldiphosphonic acid, aminotrialkylphosphonic acid and alkali metal salts and ammonium salts thereof. 1.0 g / l and 0.05 to 0.05 of surfactant
A tinting material cleaning liquid comprising 2.0 g / l and water and having a pH of 8 to 11 is sprayed from a storage tank via a pipe to a tinting material to be cleaned through a nozzle, and A tinting material cleaning method comprising returning to a storage tank and spraying again to continuously wash the tinting material without generating sludge of tin and hard water components.