JPH091060A - Surface-treated steel sheet for coated or film-laminated two-piece cans having excellent processing adhesion and processing corrosion resistance, and method for producing the same - Google Patents

Abstract

(57) Abstract: [configuration] on at least one surface of the substrate steel sheet, hydration of 5 to 30 mg / m ² lower metal layer of chromium per side 30 to 300 mg / m ^2, the upper layer is at one surface per reckoned as metal chromium A molecular weight of 1000 is obtained by forming an electrolytic chromate treatment film consisting of a chromium oxide layer, and further having polar groups such as cyano group, amino group and aminocarboxylic acid group in the molecule as an upper layer.
Contains at least one of the above organic resins and has an average amount of adhesion of 1
An organic material layer of about 1000 mg / m ² is formed. Thereby, a coated or film-laminated surface-treated steel sheet for a two-piece can having excellent processing adhesion and corrosion resistance can be obtained. [Effect] Excellent processing adhesion and processing corrosion resistance even when severe processing is applied after painting or film lamination,
Provided are a surface-treated steel sheet for a painted or film-laminated two-piece can and a method for manufacturing the same, which is applicable to any contents.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated steel sheet which is a material steel sheet for a two-piece can that is subjected to severe processing after coating or film laminating, and particularly to a coating or film excellent in adhesion and corrosion resistance after processing. Laminate 2
The present invention relates to a surface-treated steel plate for a piece can and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a conventional can manufacturing process, tin plate, electrolytic chromate treated steel plate (hereinafter referred to as T, TFS), metal plate such as aluminum is coated once or plural times, and then can manufacturing is performed. In some cases, painting may be performed after can processing. In the manufacturing process of a can lid and a cap, it is common to process after coating a metal plate.

In recent years, a technique of laminating an organic resin film on a metal plate has been developed and put into practical use. JP-A-57-182428, JP-B-61-1676.
Japanese Unexamined Patent Publication (KOKAI) publication discloses a method in which the metal plate side is heated above the melting point of the film and is bonded by heat fusion.

There are various methods for processing after coating or film laminating, and those having a particularly high degree of processing include a metal plate which is squeezed, ironed, stretched, bent, etc., alone or in combination. There is a two-piece can manufacturing method in which the can bottom part and the can body part are integrally molded by repeating the process as necessary.

On the other hand, in recent years, can makers have been making thinner can bodies from the viewpoint of material saving.
In the case of piece cans, measures such as increasing the degree of processing during can making are taken. In the production of can lids and caps, the metal plate after painting or film laminating is subjected to processing such as drawing, bending, overhanging, and screw processing.

By the way, the severe processing applied after painting or film laminating has a great influence on the morphology of the plating film of the surface-treated base steel sheet. For example, in the case of TFS, when the coating film or film is dissolved and removed from the material after draw bead processing and the plating film is observed, many cracks are generated in the metal chromium layer and the hydrated chromium oxide, and the new surface of metal chromium and iron appears. It is known to appear. This is because the resin film of the outermost layer has a large ductility, so it has a healthy appearance even if subjected to quite severe processing, but the electrolytic chromate film is extremely thin, and the hydrated chromium oxide layer has a low ductility. This is considered to be because cracks were generated due to failure to follow the deformation, and new surfaces of iron and metallic chromium were exposed.

The adhesion of the resin film and the surface-treated steel sheet after processing depends on the adhesion state after processing at the interface between the resin film and the electrolytic chromate treatment film and the adhesion state between the new surface of iron and metal chromium and the resin film. Since it depends, cracks are generated in the electrolytic chromate treatment film and the healthy adhesive interface is reduced, and the adhesive force at the new surface-resin film interface is weak, so that the adhesiveness after processing (hereinafter referred to as processing adhesiveness )
And corrosion resistance (hereinafter referred to as processing corrosion resistance) is deteriorated.

As described above, if the degree of processing is increased in order to reduce the thickness for the purpose of material saving, the deterioration of performance such as processing adhesion and processing corrosion resistance will increase. Further, the film adhesion method by heat fusion as described above also causes large deterioration in processing adhesion and processing corrosion resistance, and is not practically applicable.

As a technique for solving such a problem, a method of laminating an organic resin film to which an adhesive is applied in advance on a metal plate is disclosed in Japanese Patent Publication No. 4-74176.
It is disclosed in Japanese Examined Patent Publication No. 5-71035, Japanese Unexamined Patent Publication No. 2-70430, and the like.

According to the methods disclosed in these, the working adhesion and the working corrosion resistance are improved, but it is necessary to evaporate by heating the solvent of the adhesive, which not only complicates the process but also makes it difficult to discharge the solvent. However, there are problems such as waste treatment and increase in energy consumption, which is not preferable from the viewpoint of environmental protection.

Further, in the case where particularly severe processing is performed in the manufacturing process, further processing adhesion and processing corrosion resistance are required, and when exposed to a high temperature steam environment during retort processing, the degree of performance deterioration is further increased. Therefore, even with these techniques, the degree of improvement in work adhesion and work corrosion resistance is still insufficient, and there is a problem that some contents cannot be applied.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and is excellent in processing adhesion and processing corrosion resistance even when subjected to severe processing after painting or film laminating, and retort treatment. It is an object of the present invention to provide a surface-treated steel sheet for painting or film laminating two-piece cans, which can be applied to all contents including those requiring the above, and a method for producing the same.

[0013]

Means and Actions for Solving the Problems In order to solve the above-mentioned problems, the present inventors have proposed a TFS which is a surface-treated steel sheet having relatively good adhesion to an organic resin layer such as a coating or laminate film. The bonding mechanism at the bonding interface between the resin film and TFS was examined in detail with the above as a base. In addition, the adhesive interface in the case of severe processing after adhering to the paint or laminate film is investigated in detail, and the processing adhesiveness and processing corrosion resistance in the aqueous environment of the inner surface after filling the contents or in the high temperature steam environment during retort processing. A detailed investigation was made on the mechanism of deterioration.

As a result, in order to suppress the deterioration of work adhesion and work corrosion resistance, the hydrogen bonding force which is dominant in the adhesion between the hydrated chromium oxide layer existing on the uppermost layer of TFS and the paint or the laminate film is set. It has been found that it is important to increase the amount and it is effective to add an organic substance having a polar group. In addition, it is possible to suppress the deterioration of the characteristics by causing re-adhesion after the processing and collecting the eluted metal ions in the portion where the newly-formed metal surface appears due to the deformation due to the processing. It has been found that this is possible, and it has been found that the method of applying the above-mentioned organic substance having a polar group is also effective in this mechanism.

The present invention has nothing to do with the conventional method of applying an adhesive to a film at the time of laminating, and thus, by applying a specific organic substance to the hydrated chromium oxide layer of TFS, a coating or a film can be obtained. It has been completed by finding that the working adhesion and the working corrosion resistance after severely working the laminated steel sheet are remarkably improved.

That is, according to the present invention, firstly, at least one surface of the base steel sheet has a lower layer of 30 to 300 per surface.
mg / m ² of metallic chromium layer, the upper layer has an electrolytic chromate conversion coating consisting of hydrated chromium oxide layer of 5 to 30 mg / m ² of metal per side terms of chromium, more intramolecular polar group thereon A coating excellent in processing adhesion and processing corrosion resistance, which has an organic substance layer containing at least one kind of organic resin having a molecular weight of 1000 or more and having an average adhesion amount of 1 to 1000 mg / m ² as a solid content concentration. Provided is a surface-treated steel sheet for film-laminated 2-piece cans.

Secondly, in the organic material layer, the total weight of polar groups is 3% or more based on the total weight of organic materials, and the coating or film having excellent processing adhesion and processing corrosion resistance according to claim 1. Provided is a surface-treated steel sheet for laminated two-piece cans.

Thirdly, in any one of the above inventions, the polar group of the organic material layer is at least one selected from the group consisting of a cyano group, an amino group and an aminocarboxylic acid group. Provided is a coated or film-laminated surface-treated steel sheet for a two-piece can having excellent adhesion and processing corrosion resistance.

Fourth, by subjecting the steel sheet directly or after chromium plating to electrolytic chromate treatment, a metal chromium layer of 30 to 300 mg / m ² per side on at least one side of the steel sheet and a metal chromium layer per side above it. Two layers of a hydrated chromium oxide layer of 5 to 30 mg / m ^{2 in} terms of conversion are formed, and after washing with water or washing with water and drying, an organic substance containing at least one polymer containing a polar group in the molecule is adjusted to 0.
Provided is a method for producing a surface-treated steel sheet for painting or film laminating two-piece can, which is excellent in processing adhesion and processing corrosion resistance, which is characterized by applying an aqueous solution containing a concentration of 3 g / l or more and then drying.

According to the present invention having such a configuration,
From the viewpoint of resource saving, it is possible to suppress deterioration of processing adhesion and processing corrosion resistance due to the increase in processing degree accompanying the thinning of the can body, and it can also be applied to contents that require retort processing etc. which is a high temperature steam environment. Painting or film laminating 2
It is possible to provide the surface-treated steel sheet for a piece can without increasing the cost.

The present invention will be described in detail below. The conventional mechanism of adhesion between TFS having a hydrated chromium oxide layer on the surface and a resin film such as a film or paint is
It is considered that the dominant one is the hydrogen bond acting between the hydroxyl group of the hydrated chromium oxide layer and the polar group of the resin film. Therefore, the only way to increase the adhesion between the hydrated chromium oxide layer and the resin coating is to change the resin coating itself or the quality of the hydrated chromium oxide layer. However, even if the quality of the hydrated chromium oxide layer is changed, there is no other way but to reduce the mixing ratio of other anions contained in the electrolytic chromate treatment or to change the anion species. Since it does not change, there is a limit to the improvement of adhesion.

On the other hand, in the present invention, the hydrated chromium oxide upper layer contains an organic resin having a polar group such as a cyano group, an amino group and an aminocarboxylic acid group in the molecule and having a molecular weight of 1000 or more. The bonding mechanism itself is very different from the conventional one. That is, a molecular weight of 100 having a polar group
Since an organic resin of 0 or more causes a hydrogen bond stronger than the hydrogen bond between the hydrated chromium oxide and the resin film, the use of such an organic resin can easily improve the adhesion.

The present invention can exert not only the effect of improving the primary adhesion with the resin film described above but also the following effect. When processing is performed after adhering the resin film to TFS, the resin film can be deformed depending on the process, but the metal chrome layer and the hydrated chrome oxide layer are cracked and become island-shaped. , A new surface of metallic chromium and iron will result. In the conventional TFS, the part that bears the adhesion force after processing is dominated by the adhesion part between the hydrated chrome oxide layer and the resin film remaining after processing, and the adhesion between the new surface of iron and metal chromium and the resin film. Since the force is extremely low, the overall adhesion is significantly reduced.
However, in the surface-treated steel sheet according to the present invention, an organic resin having a polar group exists between the iron and metal chrome nascent surface appearing after processing and the resin film, and since this has an adhesive force, the adhesiveness after processing is also excellent. That is, when the adhesive force between the organic resin having a polar group and the resin film is higher than the adhesive force between the organic resin having a polar group and the hydrated chromium oxide layer, the new surface of iron and metallic chromium and the resin after processing An organic resin having a polar group exists between the films, and in the opposite case, an organic resin having a polar group is formed when the hydrated chromium oxide is broken into islands during processing. Will bridge between the islands, or will slip and stick to the resin film side. In any case, the organic resin having a polar group exists between the new surface of iron and metallic chromium and the resin film.

Further, it is considered that it is advantageous that such a polymer is three-dimensional rather than linear and leaves room for elongation to some extent due to processing deformation. Or if it is short, it is considered disadvantageous. In the environment during processing, the new surfaces of iron and metallic chromium are oxidized as quickly as possible to form hydroxyl groups.
The presence of the organic resin layer having a polar group between the newly formed surface and the resin film causes a strong adhesive force, and the adhesiveness is excellent even after processing.

Furthermore, the surface-treated steel sheet of the present invention is also excellent in adhesion in a high temperature aqueous environment or steam environment. Generally, the adhesiveness deteriorates under the above-mentioned environment because when water enters the interface between the resin film and the steel plate, the water replaces the hydrogen bond that supports the adhesive force because of the polarity of the water. It seems to be because of it. However, in the present invention, since the organic resin having a polar group has a stronger hydrogen bond than conventional TFS, it is difficult to be replaced with water, and therefore, the adhesiveness is excellent even in a high temperature aqueous environment and a steam environment.

Moreover, the fact that hydrogen bonds are difficult to be replaced by water molecules has the effect of preventing expansion leakage as well, which means that the corrosion resistance after processing is also excellent. Furthermore,
Polar groups such as a cyano group, an amino group, and an aminocarboxylic acid group also have the ability to chelate metal ions, and thus have the ability to collect eluted iron ions. For this reason, the polar groups collect the eluted iron ions. In a system in which the new surface of iron is exposed after processing, conventional TFS does not have such an iron ion collecting mechanism. Therefore, the surface-treated steel sheet of the present invention has dramatically improved work corrosion resistance as compared with the conventional TFS.

The reasons for limiting the invention will be described below.
In the present invention, at least one surface of the base steel sheet has a two-layer electrolytic chromate treatment film having a lower layer of a metallic chromium layer and an upper layer of a hydrated chromium oxide layer.

Here, the amount of metallic chromium deposited on the lower layer is 30 to 300 mg / m ² per side. The adhesion amount is 30
If it is less than mg / m ² , problems occur in corrosion resistance,
If it exceeds mg / m ² , the workability is deteriorated, which is not preferable.
In any case, there is no problem as long as it is the amount used for a usual electrolytic chromate-treated steel sheet.

The amount of hydrated chromium oxide deposited on the upper layer is 5 to 30 mg / m ^{2 in} terms of metallic chromium per side. If the adhered amount is less than 5 mg / m ² , the metal chromium layer is not uniformly covered with the hydrated chromium oxide, the exposed area of the metal layer becomes large, and corrosion resistance, deterioration with time resistance, and work adhesion are inferior, which is not preferable. On the other hand, if it exceeds 30 mg / m ² , it is not preferable because the hydrated chromium oxide layer is too thick, resulting in deterioration of appearance and adhesion.

On the electrolytic chromate-treated film, at least one organic resin having a polar group in the molecule and having a molecular weight of 1000 or more is contained, and the average adhesion amount is 1 to 1 as the solid content concentration.
An organic layer of 000 mg / m ² is formed. Here, as the organic material layer containing a resin having a polar group in the molecule,
It is preferable that the total weight of polar groups is 3% or more based on the total weight of organic substances. This is because the polar group can effectively function above this concentration and can exert the effect of significantly improving the adhesiveness.

In the present invention, the polar group may be a cyano group, an amino group or an aminocarboxylic acid group, as mentioned above. The organic resin having at least one of these groups in the molecule is specifically, , Polyacrylonitrile, vinyl alcohol, vinyl aminocarboxylate copolymer, polyacrylamide, copolymers containing these, and the like, and the organic layer contains one or more of these. In addition to the organic resin having the polar group in the molecule, the organic layer may contain other organic substances such as polyethylene glycol and polypropylene glycol.

The molecular weight of the organic resin having a polar group in its molecule must be at a high molecular level of 1,000 or more. The reason why the molecular weight is specified to be 1000 or more is that if the molecular weight is low, it cannot be stretched during processing as described above, and the processing adhesion cannot be sufficiently improved. The upper limit of the molecular weight of the organic resin is not particularly limited, but it is preferably 5 million or less.

The average amount of the organic material layer deposited is 1 to 1000 mg.
/ M ² . 1m to effectively improve the adhesion
g / m ² is the minimum requirement, and 1000 mg / m ²
Even if it exceeds, the adhesion improving effect is saturated, the organic layer becomes thicker, and cohesive failure easily occurs in the polymer, which adversely affects the adhesion. Further, in order to set the average amount of adhesion to 100 mg / m ² or more, it is necessary to have suitable equipment capable of uniformly adhering organic substances so as not to impair the surface appearance, and because it takes time to dry, TFS It is uneconomical because it becomes difficult to manufacture in-line on the manufacturing line. Therefore, it is preferable that the average adhesion amount is less than 100 mg / m ² .

In the present invention, by subjecting the steel sheet directly or after chrome plating to electrolytic chromate treatment, at least one surface of the steel sheet has a surface area of 30 to 300 m per side.
Two layers of a hydrated chromium oxide layer of 5 to 30 mg / m ^{2 in} terms of metal chromium per surface are formed on the g / m ² metal chromium layer and the upper layer thereof, and after washing with water or washing with water and drying,
An aqueous solution containing an organic substance containing at least one kind of polymer having a polar group in the molecule at a concentration of 0.3 g / l or more is applied,
Then, it is dried to manufacture the surface-treated steel sheet having the above-mentioned configuration.

Here, the electrolytic chromate treatment method is a one-liquid method in which metallic chromium and hydrated chromium oxide are simultaneously precipitated,
Alternatively, any of the two-liquid method of depositing hydrated chromium oxide after forming the metal chromium layer may be used.

As an aqueous solution to be applied on the electrolytic chromate-treated film when forming the organic material layer, 0.3 g of the organic material is used.
/ L or more is preferable. This is because if the concentration is less than this concentration, an effective amount will not be adsorbed on the surface of the steel sheet, and it will be difficult to sufficiently enhance the adhesion.

The base steel sheet is not particularly limited, and any steel sheet usually used for this type of surface-treated steel sheet can be used, for example, a low carbon Al killed steel sheet or the like can be applied.

[0038]

Next, specific examples of the present invention will be described. [Samples] (1) Surface-treated steel sheets All examples and comparative examples are low carbon Al killed continuous cast steels, and a T0CA material having a thickness of 0.20 mm was used as a raw steel strip.
It was manufactured using a vertical TFS line.

Then, after the electrolytic chromate treatment shown in Table 1, an aqueous solution of an organic substance or an aqueous solution in which an organic substance emulsion was dispersed was applied under the same conditions as shown in Table 1 and dried to form an organic layer. The amount of the organic material layer deposited was controlled by adjusting the pressing pressure of the squeezing roll or setting the coating roll. The substances used for the organic material layer are shown in Table 2.

(2) Coating 200 × 3 of the surface-treated steel sheet described in Examples and Comparative Examples
A cut plate of 00 mm was formed, and epoxy resin paint was applied on both sides of the cut plate under the following conditions and baked.

Epoxy resin paint adhesion amount: 60 mg / dm ² (after drying) Baking temperature: 210 ° C. Baking time: 10 minutes (3) Film lamination The surface-treated steel sheet described in Examples and Comparative Examples was 200 × 3.
A cut plate of 00 mm was formed, and a commercially available polyester film was laminated on both sides of the cut plate under the following conditions.

Film: Biaxially oriented polyester film (polyethylene glycol and terephthalic acid / isophthalic acid copolymer) Film thickness: 25 μm Crystal melting temperature of film: 229 ° C. Steel sheet temperature immediately before lamination: 235 ° C. Laminating speed: 2 m / Sec Cooling after lamination: Water cooling (rapid cooling) [Evaluation] (1) Drawing work A coated or laminated surface-treated steel plate was punched into a disk having a diameter of 158 mm, and drawn into a cylindrical cup with a drawing ratio of 2.92. Then, the peeling condition of the film or coating on the inner surface of the cup was observed with a loupe. At that time, a good state without peeling was set to 5 points, and evaluation was performed in 5 grades so that the degree of peeling increased as the point decreased to 4 points, 3 points, 2 points and 1 point.

Further, retort treatment was performed for 90 minutes in a 1.5% NaCl + 1.5% citric acid aqueous solution, and after washing with water and drying, the peel strength of the inner surface of the cup was similarly evaluated on a scale of 5 on the same basis.

(2) Bending process Painted or laminated surface-treated steel plate 30 × 300 mm
Using a tool with a tip R of 0.25 mm, perform a draw bead test with a pressing pressure of 1000 kgf, and further perform 15% compression processing with a rolling mill, and apply a loupe to the opposite side of the draw bead tool contact surface. Observed at. At that time, the degree of peeling was evaluated on a scale of 5 as in the case of the drawability evaluation.

Further, retort treatment was carried out for 90 minutes in a 1.5% NaCl + 1.5% citric acid aqueous solution, and similarly, the opposite side of the contact surface of the draw bead tool was observed with a magnifying glass and evaluated in 5 grades based on the same criteria.

(3) Repack test A laminated surface steel plate was punched into a disk having a diameter of 110 mm,
First, apply a cylindrical cup squeeze with a squeeze ratio of 1.51,
Then, redrawing was performed at a drawing ratio of 1.20 to form a cylindrical cup (total drawing ratio of 1.81). The peeling condition of the film on the inner surface of the cup was observed with a magnifying glass, and the same criteria as above were used to evaluate the grade in five levels.

In addition, Coca-Cola (trademark) is added to the cup.
Was repacked and subjected to a storage test at 38 ° C. for 3 months.
After the storage test, the state of peeling between the film on the inner surface of the cup and the metal plate was observed with a loupe, and the same criteria as above were used to rate 5 grades. At the same time, the iron ion eluted in Coca-Cola was determined by the atomic absorption method.

The results of these evaluations are also shown in Table 1.
As shown in Table 1, the surface-treated steel sheets of Examples which are within the scope of the present invention not only have excellent primary adhesion after coating or film laminating, but also adhesion after processing, and further after retort treatment. It was confirmed that the adhesiveness was excellent. In addition, it was confirmed that the amount of iron leached out when the contents were stored for a long period of time was extremely small, and the processing corrosion resistance was remarkably improved.

On the other hand, the comparative examples out of the scope of the present invention were particularly inferior in processing adhesion after retort treatment and corrosion resistance during storage of contents. As described above, it was confirmed that by using the surface-treated steel sheet according to the present invention, excellent work adhesion and work corrosion resistance can be obtained regardless of the electrolytic chromate treatment method. The present invention is not limited to the above-mentioned embodiments, but can be implemented in various other modes without departing from the scope of the present invention.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

As described above, according to the present invention,
It is excellent in processing adhesion and corrosion resistance even when subjected to severe processing after painting or film lamination, and can cope with an increase in processing degree due to thinning of the can body, and requires retort treatment. Provided are a surface-treated steel sheet for a painted or film-laminated two-piece can and a method for producing the same, which can be applied to any content such as the above. As described above, according to the present invention, excellent work adhesion and work corrosion resistance can be obtained without going through complicated steps, so that the economical value thereof is extremely high.

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Claims (4)

[Claims] 1. A metal chromium layer having a lower layer of 30 to 300 mg / m ^{2 on} one surface of at least one surface of a base steel sheet,
The upper layer is 5 to 30 mg / m ^{2 in} terms of metal chromium per side
Of the hydrated chromium oxide layer, which further contains at least one organic resin having a molecular weight of 1000 or more and having a polar group in the molecule in the upper layer, and the average amount of adhesion is 1 to 1 as a solid content concentration. 1000 mg / m and having an organic substance layer is ^2, coating with excellent processability adhesion and processability corrosion or film laminate 2
Surface-treated steel plate for piece cans. 2. The coating or film laminate 2 having excellent process adhesion and process corrosion resistance according to claim 1, wherein the total weight of the polar groups in the organic layer is 3% or more based on the total weight of the organic substances. Surface-treated steel plate for piece cans. 3. The polar group of the organic layer is at least one selected from the group consisting of a cyano group, an amino group, and an aminocarboxylic acid group, according to claim 1 or 2. A coated or film-laminated surface-treated steel sheet for 2-piece cans with excellent processing adhesion and corrosion resistance. 4. A metal chromium layer of 30 to 300 mg / m ² per surface on at least one surface of the steel plate and an upper layer thereof in terms of metal chromium conversion per surface by subjecting the steel plate directly or after chromium plating to electrolytic chromate treatment. 5
-30 mg / m ² of ^two hydrated chromium oxide layers are formed, and after washing with water or washing with water and drying, 0.3 g of an organic substance containing at least one polymer containing a polar group in the molecule
A method for producing a coated or film-laminated surface-treated steel sheet for a two-piece can, which is characterized by coating an aqueous solution containing a concentration of 1 / l or more and then drying.