JPH1044314A - Coated metal plate and can using the coated metal plate - Google Patents

Abstract

An object of the present invention is to use a masterbatch containing titanium oxide which is rich in dispersibility and hydrophobicity and low in water content, and has dispersibility, smoothness, whiteness, and concealability of a substrate. Another object of the present invention is to provide a coated metal sheet which is excellent in light discoloration resistance, weather discoloration resistance and the like, and is coated with a coating layer which does not deteriorate physical properties. SOLUTION: The colorant composition contains titanium oxide treated with 0.05 to 3.0% by weight of triethanolamine and a polyester resin (1), and is heated and kneaded. A colorant composition in which the intrinsic viscosity retention of the polyester resin in the product is 80% or more, and a coated metal obtained by melt-extruding and laminating a polyester resin composition using the polyester resin (2) on a metal plate. Board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coated metal plate obtained by melt-extruding and laminating a polyester resin composition containing titanium oxide on at least one surface of a metal plate. More specifically, it relates to a coated metal plate which is excellent in smoothness, whiteness, light discoloration resistance, weather discoloration resistance and can improve the image quality of a layer formed on the surface, and more particularly, is suitable for cans containing beverages or foods. The present invention relates to a coated metal plate.

[0002]

2. Description of the Related Art Conventionally, methods for obtaining a coated metal plate include a method of applying a solvent-type or aqueous coating composition (paint) to a metal plate, a method of spraying a powder coating onto a metal plate, and a method of applying heat or heat. There are a method of laminating a film made of a thermoplastic resin composition with or without an adhesive, a method of melt-extruding and laminating a thermoplastic resin composition on a metal plate, and the like.

Solvent-type or aqueous coating compositions (paints)
Is applied to a metal plate, a solvent-type or aqueous coating composition (paint) is applied to the metal plate, heated, and the resin component in the paint is cured, and a coating layer is provided on the metal plate. . In the case of such a method, the coating material must contain components other than the effective components necessary for constituting the final coating layer, that is, components such as an organic solvent and water which volatilize during heat curing. Therefore, it is required to reduce the content of components such as an organic solvent and water and to increase the content of an effective component in a coating material. But,
There is a limit to reducing the content of components such as organic solvent and water in order to secure the paintability as a paint. Especially in the case of solvent-based paints, not only large-scale and expensive equipment is required to recover the volatile solvent, but also a switch to non-solvent paints is desired from the viewpoint of environmental safety and occupational health. It is rare.

[0004] In the method of spraying a powder coating on a metal plate, a powder coating, which is a 100% effective component, is sprayed on the metal plate and melted on the metal plate to form a continuous film. Since there is no such a problem as above, it is difficult to obtain a film of uniform thickness because the powder is melted on a metal plate, especially in the case of a thin film, for example, 50 μm or less, especially in the case of a thin film of 25 μm or less It is extremely difficult to control the film thickness. The coating speed also has a significant effect on the film thickness, and is a coating method unsuitable for high-speed coating, and there is a problem in terms of productivity.

[0005] In the case of a method of laminating a film made of a thermoplastic resin composition to a metal plate using an adhesive, it is necessary to first prepare a film and further apply a step of applying an adhesive. Yes, the number of steps increases, which is not preferable. In addition, in the case of a method of bonding a film made of a thermoplastic resin composition to a metal plate without using an adhesive, the step of applying the adhesive is not necessary, but the metal plate is used more than when an adhesive is used. It is necessary to heat at a high temperature and uniformly. If the temperature of the metal plate is uneven, the adhesion of the coating layer becomes uneven. It is difficult to uniformly heat a large metal plate at a high temperature, and it requires a lot of energy.Therefore, such a method is easy to apply to a relatively small metal plate, but it is difficult to coat a large metal plate. Improper.

Compared with the above-described methods, the method of extrusion laminating a melt of a thermoplastic resin composition directly on a metal plate has no volatile components (100% effective component) and a thin film. It is excellent in that a coating layer can be formed and a step of manufacturing a film in advance is unnecessary.

Conventionally, polyester resins have been used for packaging by taking advantage of their excellent mechanical properties, dimensional stability and chemical resistance.
It is used in many fields such as film applications. In addition, titanium oxide is used in a large amount as a white pigment for resin coloring because of its excellent whiteness, high concealing property, and high coloring power. recent years,
A colorant composition containing a polyester resin having such excellent properties and titanium oxide having an excellent concealing property, a metal plate laminate film, a film for a credit card or a telephone card, or a fiber or other various other It is widely used for molded articles, and the range of use tends to expand more and more.

The titanium oxide used for coloring the polyester resin is generally subjected to various surface treatments in order to improve weather resistance, dispersibility and the like. This surface treatment is carried out by inorganic treatment (alumina, silica, titania,
Zirconia, etc.) and organic treatment (polyol, silicon). By the treatment as described above, the dispersibility of titanium oxide in the polyester resin is improved, and the weather resistance of a molded article containing the titanium oxide is also improved.

However, even the titanium oxide treated as described above generally has a considerable amount of water, and the water causes hydrolysis of the polyester-based resin in the colorant composition, resulting in a decrease in molecular weight. Decrease.
The colorant composition containing the polyester resin having the reduced molecular weight causes a decrease in the physical properties of a molded article using the colorant composition. In particular, when a high concentration of titanium oxide is contained in the colorant composition, the decrease in the molecular weight of the polyester-based resin becomes remarkable. Become noticeable.

[0010] The colorant composition used for coloring and molding a thermoplastic resin includes a powdery dry color obtained by mixing a pigment and a dispersant, and a liquid color obtained by dispersing a pigment in a liquid dispersant at room temperature. Alternatively, there is a master batch in which a pigment is dispersed at a high concentration in a resin of a paste color or a solid at room temperature to form a pellet or a flake. In particular, a masterbatch excellent in ease of handling and preservation of the working environment during use is often used.

A colorant composition (master batch) obtained by dispersing a pigment at a high concentration in a polyester resin is melted and kneaded with a polyester resin for dilution and extruded on a metal plate to obtain a coated metal plate. It is used to obtain molded articles such as films, fibers and the like. In the field of coated metal sheets, in recent years, there has been a strong demand for improved productivity, that is, high-speed workability during melt extrusion lamination, in accordance with demands for cost reduction. When the polyester resin composition is melt-extruded and laminated at a high speed, the film thickness is reduced,
A problem arises in that the desired hiding property cannot be obtained with the conventional titanium oxide content. In order to solve such a problem, a method of ensuring a desired hiding property by containing a large amount of titanium oxide in a polyester resin composition has been attempted. But,
Various problems have been caused by a large amount of water derived from a large amount of titanium oxide.

That is, when a colored resin molded product is generally manufactured using a masterbatch containing a large amount of titanium oxide and having a high water content and a thermoplastic resin such as a polyester resin for dilution, extrusion molding is required. The masterbatch and the thermoplastic resin, etc., slip due to the moisture generated from the masterbatch in the machine, causing poor dispersion, or the moisture returns to the raw material supply port side of the processing machine to supply the raw material smoothly. The problem of being unable to do so occurs.

Further, as described above, the polyester resin in the colorant composition such as a masterbatch is hydrolyzed by the water contained in the titanium oxide, and the molecular weight of the polyester resin is reduced. It may cause deterioration of physical properties. The same applies to the case of melt extrusion lamination.When a coated metal plate is to be obtained by using a colorant composition containing a polyester resin having a reduced molecular weight, a hole is opened in the coating layer, and the metal plate is formed. In some cases, it could not be uniformly covered. In addition, in the coating process, the properties of the coating layer on the coated metal plate are reduced even if holes are not opened.As a result, the coated metal plate is processed, for example, a flat coated metal plate is punched in a round shape, drawn and ironed. For example, when a two-piece can body is made by applying the method described above, the coating layer having deteriorated physical properties may not be able to withstand the above-described processing and may be broken, or may have poor adhesion and peel off from the metal plate. Alternatively, even if it can withstand the processing in the can making process, it may be damaged by retort treatment for sterilization after accommodating a beverage or the like, neck-in processing, or the like.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to use a masterbatch containing titanium oxide which is rich in dispersibility and hydrophobicity and has a low water content, and has a dispersibility, smoothness, whiteness and concealment property of a substrate. Another object of the present invention is to provide a coated metal sheet which is excellent in light discoloration resistance, weather discoloration resistance and the like, and is coated with a coating layer which does not deteriorate physical properties.

[0015]

That is, a first invention comprises titanium oxide treated with 0.05 to 3.0% by weight of triethanolamine and a polyester resin (1), and is heated and kneaded. A colorant composition, wherein the polyester resin in the colorant composition has an intrinsic viscosity retention of 8
A coated metal plate obtained by melt-extruding and laminating a polyester-based resin composition using a colorant composition of 0% or more and a polyester resin (2) on a metal plate.

According to a second aspect, the composition is treated with 0.01 to 0.5% by weight of calcium salt or magnesium salt in terms of calcium oxide or magnesium oxide and 0.05 to 3.0% by weight of triethanolamine. A colorant composition containing titanium oxide and a polyester resin (1) and kneaded by heating, wherein the intrinsic viscosity retention of the polyester resin in the colorant composition is 80% or more. A coated metal plate obtained by melt-extruding and laminating a polyester-based resin composition using a polyester resin and a polyester resin (2) on a metal plate.

According to a third aspect of the present invention, a titanium oxide treated with 0.01 to 0.3% by weight of alumina or silica and 0.05 to 3.0% by weight of triethanolamine, and a polyester resin (1) are provided. A colorant composition containing, heated and kneaded, wherein the colorant composition has a limiting viscosity retention of 80% or more of the polyester resin in the colorant composition, and a polyester resin (2). Is a coated metal plate obtained by melt-extruding and laminating a polyester-based resin composition on a metal plate.

According to a fourth aspect of the present invention, a calcium salt or a magnesium salt of 0.01 to 0.5% by weight in terms of calcium oxide or magnesium oxide is added to an alumina of 0.01 to 0.3% by weight in terms of alumina or silica. Oxide treated with silicate or silicate and 0.05 to 3.0% by weight of triethanolamine, and polyester resin (1)
And a heat-kneading colorant composition, wherein the polyester resin (2) has a limiting viscosity retention of 80% or more of the polyester resin in the colorant composition. This is a coated metal plate obtained by melt-extruding and laminating the polyester resin composition used on a metal plate.

A fifth invention is a titanium oxide treated with 0.01 to 0.5% by weight of a calcium salt or a magnesium salt and 0.05 to 3.0% by weight of triethanolamine,
A colorant composition containing a polyester resin (1) and heat-kneaded, wherein the intrinsic viscosity retention of the polyester resin in the colorant composition is 80% or more; and a polyester It is a coated metal plate obtained by melt-extruding and laminating a polyester resin composition using the resin (2) on a metal plate.

In a sixth aspect, a calcium salt or a magnesium salt of 0.01 to 0.5% by weight, an aluminate or a silicate of 0.01 to 0.3% by weight, and a 0.05 to 3.0% are provided. Titanium oxide treated with wt% triethanolamine,
A colorant composition containing a polyester resin (1) and heat-kneaded, wherein the intrinsic viscosity retention of the polyester resin in the colorant composition is 80% or more; and a polyester It is a coated metal plate obtained by melt-extruding and laminating a polyester resin composition using the resin (2) on a metal plate.

According to a seventh aspect of the present invention, the calcium salt is selected from calcium chloride, calcium bromide, calcium iodide, and calcium sulfate. Or a coated metal plate as described above.

According to an eighth invention, the magnesium salt is magnesium chloride, magnesium bromide, magnesium iodide,
A coated metal plate according to the second invention or any of the fourth to sixth inventions, wherein the metal plate is selected from magnesium sulfate.

A ninth invention is the coated metal plate according to any one of the first to eighth inventions, wherein the metal plate is one kind selected from the group consisting of a steel plate and an aluminum plate.

[0024] A tenth invention is a beverage or food can using the coated metal sheet according to any one of the first to ninth inventions.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The mechanism by which the triethanolamine used in the present invention works compared to general polyols such as trimethylolpropane and trimethylolethane is not yet well understood, but treatment with triethanolamine is not yet clear. The resulting colorant composition containing titanium oxide has high hydrophobicity, low water content, and excellent dispersibility and high-temperature processability as compared with the above-mentioned general polyols.

The titanium oxide used in the colorant composition (masterbatch) used in the present invention contains the triethanolamine in an amount of 0.05 to 3.0% by weight, preferably 0.05 to 1%. 0.0% by weight, more preferably 0.1 to 0.5% by weight, most preferably 0.1 to 0.3% by weight. When the content is less than 0.1% by weight, the effect of hydrophobizing the titanium oxide is small, and the amount of water absorbed over time after the production of the colorant composition increases, and the polyester in the colorant composition becomes the same as before. It promotes hydrolysis of the resin and causes a decrease in molecular weight. Also, 3.
Even if the content is more than 0% by weight, the effect is hardly changed.

The calcium salt or magnesium salt used in the present invention is used to fix the hydroxyl group by reacting with the hydroxyl group on the surface of titanium oxide and to make the titanium oxide hydrophobic. Such calcium salts or magnesium salts include calcium chloride, calcium bromide, calcium iodide, calcium sulfate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate and the like.

The content is 0.01 to 0.5% by weight in terms of calcium oxide or magnesium oxide. If the content is less than 0.01% by weight, the effect of hydrophobization is insufficient, and if the content is more than 0.5% by weight, the effect of hydrophobization hardly changes.

The content of the calcium salt and the magnesium salt as described above is 0.01 to 0.5% by weight. If the content is less than 0.01% by weight, the effect of hydrophobization is insufficient, and if the content is more than 0.5% by weight, the effect of hydrophobization hardly changes.

In the present invention, the treatment with triethanolamine and the treatment with calcium salts or magnesium salts for fixing the hydroxyl groups on the surface of titanium oxide can be used in combination. A treatment with alumina, silica or the like using an aluminate or silicate such as sodium aluminate can be further used in the combined system. That is, after treating titanium oxide with aluminate or silicate, etc., it may be treated with triethanolamine, or after treating titanium oxide with calcium salt, etc., with aluminate, silicate, etc. Treatment, and then with triethanolamine.

Alumina, silica, and the like generally contain water of crystallization or are hydrated, and although it is preferable to reduce the water content as much as possible from the viewpoint of reducing the water content, a strong concealing property is required. In the field, it is preferable to contain as little alumina or silica as possible, preferably 0.3% by weight or less, more preferably 0.2% by weight or less based on titanium oxide.
If it exceeds 0.3% by weight, the water content increases, and the hydrolysis of the polyester resin is easily promoted. Alumina is more preferable in terms of excellent dispersibility.

The titanium oxide used in the present invention is:
The average particle size is preferably 0.01 to 1.0 μm,
More preferably, the thickness is 0.05 to 0.40 μm.
Most preferably, it is 15 to 0.20 μm. Any of rutile type and anatase type may be used, but anatase type is preferable from the viewpoint of whiteness, and rutile type is preferable from the viewpoint of masking property.

When neither treatment with an organic treatment agent such as triethanolamine or treatment with an inorganic treatment agent such as alumina is performed, the dispersion of titanium oxide is extremely poor, and the dispersion in the colored resin molded product is very poor. Aggregates are generated and clogging of the screen mesh of the molding machine is caused.

The polyester resin used in the present invention (1)
(2) is a conventionally known homo or copolyester which can be obtained by condensation polymerization of terephthalic acid and / or isophthalic acid as shown below and a glycol such as ethylene glycol, diethylene glycol, tetramethylene glycol or the like. . As the acid component, a divalent carboxylic acid such as naphthalene-2,6-dicarboxylic acid, 4,4′-biphenyldicarboxylic acid, sebacic acid, and adipic acid can be used in addition to the above terephthalic acid and isophthalic acid. . As the diol component, hexamethylene glycol, neopentyl glycol, cyclohexane dimethanol, and the like can be used in addition to the above-mentioned ethylene glycol, diethylene glycol, and tetramethylene glycol. The polyester resin (1) and the polyester resin (2) may be the same or different.

The colorant composition used in the present invention comprises the titanium oxide and the polyester resin (1) in a ratio of 2/8 to 8 /
The mixing ratio may be 2 and preferably 5/5 to 7/3, and the titanium oxide and the polyester resin may be heated and kneaded using various mixers, dispersers and kneaders.
Further, the colorant composition used in the present invention is preferably a pellet-like or flake-like master batch.

The limiting viscosity of the polyester resin in the colorant composition used in the present invention indicates the state of degradation (hydrolysis) of the polyester resin. A colorant composition containing titanium oxide and a polyester resin (1), which is heated and kneaded, is dissolved in a polyester resin in the colorant composition using an appropriate solvent, and the titanium oxide is separated. Using a plurality of polyester resin solutions having different concentrations, the viscosities of the respective resin solutions were determined, and the viscosity / concentration values were plotted against the concentrations according to a standard method, and extrapolated to a concentration of 0 to obtain the values. The intrinsic viscosity retention rate is a ratio of the intrinsic viscosity of the polyester resin in the colorant composition to the intrinsic viscosity of the polyester resin (blank) used in the colorant composition. As the intrinsic viscosity of the polyester resin in the colorant composition approaches the intrinsic viscosity of the blank, the polyester resin in the colorant composition is not deteriorated.

The metal plate used in the present invention is preferably a steel plate or an aluminum plate. The board thickness is preferably about 0.1 to 0.5 mm, and 0.15 to 0.3 mm
Is more preferred.

The coated metal sheet of the present invention is obtained by forming a melt of a colorant composition (master batch) and a polyester-based resin composition using the polyester resin (2) on a running metal sheet through a slit die into a film. And the film-shaped melt is laminated on a metal plate.
The melt extrusion temperature at that time is 250 to 320 ° C, preferably 270 to 300 ° C.

The thickness of the coating layer of the coated metal plate of the present invention is 5
About 100 μm, preferably 10 to 50 μm, more preferably 10 to 25 μm.

Although the use of the coated metal sheet of the present invention is not particularly limited, it is particularly preferably processed into a can for storing beverages and foods. The so-called two-piece can body consisting of two members, a can body and a can lid, for cans containing drinks and foods, punches a flat coated metal plate in a round shape and squeezes it so that the coating layer is on the outer surface of the can. It is processed into a can shape. The thickness of the coating layer after processing is about 3 to 65 μm, preferably 6 to 35 μm, and more preferably 6 to 17 μm.

The polyester resin composition for a coated metal plate of the present invention may contain other resins, for example, an epoxy resin or a phenoxy resin, as long as the effect is not impaired. Known additives such as an ultraviolet absorber can be added as necessary.

[0042]

【Example】

Examples 1 and 2, Comparative Examples 1 to 5 50% by weight of homopolyethylene terephthalate ((η) = 0.630) and 50% by weight of anatase-type titanium oxide (each having been subjected to each treatment shown in Table 1) were added to a melt kneader. The mixture was melt-kneaded to obtain a pellet-shaped colorant composition (master batch), and the intrinsic viscosity retention of the polyester resin in the obtained master batch was determined according to the following method. In addition, the dispersibility of the obtained master batch was evaluated, and a coated metal plate was prepared using the obtained master batch, and its physical properties and the like were evaluated. Table 1 shows the results. In Comparative Examples 2 and 5,
An odor was generated when creating the master batch.

[Intrinsic Viscosity (η)] and [Intrinsic Viscosity (η) Retention] The intrinsic viscosity (η) was 0.1% for each of the polyester resins.
g, 0.3 g, 0.5 g of the masterbatch,
Using 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio), the polyester resin in the master batch was dissolved, and the titanium oxide was removed by centrifugation. It was measured and determined according to the usual method. In the case of a blank, the limiting viscosity was obtained in the same manner as described above, except that the polyester resin itself was used instead of the master batch and the titanium oxide was not removed by centrifugation. The intrinsic viscosity retention is the intrinsic viscosity of the polyester resin in the master batch / the intrinsic viscosity of the blank.

[Evaluation method of dispersibility] 40/80 / outlet of Labo Plastomill single screw extruder 20 mm (manufactured by Toyo Seiki)
A screen having a mesh size of 120/500 was sequentially installed, and the mixture was passed through a pellet in which homopolyethylene terephthalate ((η) = 0.630) and a master batch were mixed at a ratio of 1: 1 at 50 rpm and an extrusion temperature of 300 ° C. The initial pressure (P1) at that time is determined, and the end pressure (P2) at the time when the pellets mixed at a ratio of 1: 1 have been passed through a predetermined amount (an amount containing 360 g of titanium oxide in the pellets) is determined. It can be said that the smaller the pressure difference ΔP = P2-P1, the better the dispersibility of the titanium oxide.

[Production method of coated metal plate] 40 parts by weight of the obtained master batch, homopolyethylene terephthalate
((η) = 0.630) 60 weights were mixed and melted, and 270-300
At ℃ steel plate, or melt extruded into a film on the aluminum plate to have a film thickness of 12μ and laminated.
The appearance and the like of the coating layer were evaluated.

[Appearance state of coating layer] A: The coating layer could be formed smoothly without breaking. Δ: Occasional fracture. ×: Breaks frequently.

[Smoothness of coating layer]: Visual evaluation. ：: uniform and smooth. Δ: Slight bumps occur. ×: Markedly formed.

[0048]

[Table 1]

[0049]

According to the present invention, it is possible to obtain a metal plate coated with a polyester resin composition having high dispersion and little deterioration in physical properties.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Ishikawa 2-3-113 Kyobashi, Chuo-ku, Tokyo Inside Toyo Inki Manufacturing Co., Ltd. (72) Inventor Hisashi Kaneko 2-3-1 Kyobashi, Chuo-ku, Tokyo Toyo Inki Manufacturing Co., Ltd.

Claims (10)

[Claims] 1. A colorant composition comprising titanium oxide treated with 0.05 to 3.0% by weight of triethanolamine and a polyester resin (1), which is heated and kneaded, wherein the colorant composition is A coating obtained by melt-extruding and laminating a colorant composition having an intrinsic viscosity retention rate of the polyester resin in the composition of 80% or more and a polyester resin composition using the polyester resin (2) on a metal plate. Metal plate. 2. Titanium oxide treated with 0.01 to 0.5% by weight of calcium salt or magnesium salt and 0.05 to 3.0% by weight of triethanolamine in terms of calcium oxide or magnesium oxide, and A colorant composition containing a polyester resin (1) and heated and kneaded, wherein the intrinsic viscosity retention of the polyester resin in the colorant composition is 80% or more, and a polyester resin (2) A coated metal plate obtained by melt-extruding and laminating a polyester-based resin composition obtained by using the above method on a metal plate. 3. A heating method, comprising: a titanium oxide treated with 0.01 to 0.3% by weight of alumina or silica and 0.05 to 3.0% by weight of triethanolamine; and a polyester resin (1). A colorant composition obtained by kneading, wherein the polyester resin in the colorant composition has an intrinsic viscosity retention of 80% or more, and a polyester resin (2). A coated metal plate obtained by melt-extruding and laminating a resin composition on a metal plate. 4. 0.01 to 0.5% by weight of calcium salt or magnesium salt in terms of calcium oxide or magnesium oxide and 0.01 in terms of alumina or silica.
~ 0.3% by weight of aluminate or silicate and 0.05
A colorant composition containing titanium oxide treated with 0.1% to 3.0% by weight of triethanolamine and a polyester resin (1), and heated and kneaded, wherein the polyester resin in the colorant composition is A coated metal plate obtained by melt-extruding and laminating a colorant composition having an intrinsic viscosity retention of 80% or more and a polyester resin composition using the polyester resin (2) on a metal plate. 5. A polyester resin (1) comprising titanium oxide treated with 0.01 to 0.5% by weight of a calcium or magnesium salt and 0.05 to 3.0% by weight of triethanolamine, and a polyester resin (1). A colorant composition obtained by heating and kneading, wherein the colorant composition has an intrinsic viscosity retention of 80% or more of the polyester resin in the colorant composition, and a polyester resin (2). A coated metal plate obtained by melt-extruding and laminating a polyester resin composition on a metal plate. 6. 0.01 to 0.5% by weight of calcium or magnesium salt, 0.01 to 0.3% by weight of aluminate or silicate and 0.05 to 3.0% by weight of triacetate. A colorant composition containing titanium oxide treated with ethanolamine and a polyester resin (1) and heat-kneaded, wherein the polyester resin in the colorant composition has an intrinsic viscosity retention of 80% or more. A coated metal plate obtained by melt-extruding and laminating a polyester-based resin composition using the colorant composition and the polyester resin (2) on a metal plate. 7. The coated metal sheet according to claim 2, wherein the calcium salt is selected from calcium chloride, calcium bromide, calcium iodide, and calcium sulfate. 8. The magnesium salt is magnesium chloride,
7. The coated metal sheet according to claim 2, wherein the coated metal sheet is selected from magnesium bromide, magnesium iodide, and magnesium sulfate. 9. The coated metal plate according to claim 1, wherein the metal plate is one selected from the group consisting of a steel plate and an aluminum plate. 10. A beverage or food can using the coated metal sheet according to any one of claims 1 to 9.