JP2003034322A - Coated metal plate and drawn/ironed can using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated metal plate for a drawn/ironed can, the coating film of which has excellent adhesive to the metal, which has toughness and excellent workability, and can withstand drawing/ironing. SOLUTION: The coated metal plate for the drawn/ironed can is a double coated metal plate, includes a film serving as the inner side of the can after working which has a dry coating amount of 90-400 mg/100 cm<2> , a glass transition temperature of 50-120 deg.C, and also a pencil hardness of >=H, an elongation percentage of 200-600%, and a coefficient of kinetic friction of 0.03-0.25 under test conditions at 60 deg.C, and a film serving as the outer side of the can after working which has a dry coating amount of 15-150 mg/100 cm<2> , a glass transition temperature of 50-120 deg.C, and also a pencil hardness of >=H under the test conditions at 60 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided coated metal sheet for cans, and more particularly to a coated metal sheet capable of withstanding high-speed and severe processing such as drawing and ironing (DI processing, Draw and Ironing).

[0002]

2. Description of the Related Art Used in food cans, etc. 2
Depending on the manufacturing method of the piece can, the squeezed squeezed can (DI can: Draw and Irone
d Can) and a squeeze can that does not contain ironing (DR can: Drawn
Can), DRD can: Drawn and Redrawn
Can) and DTR can (Drawn Thin Redraw Can). Of these, DI cans are often used for positive pressure beverage cans such as beer and carbonated drinks because of their beauty and thinness and light weight. However, in the production of DI cans, it is necessary to use a large amount of coolant, degreasing, washing with water, and surface-treating, then spray coating the inner surface and baking to dry. The environmental load was also great.

In order to solve such a problem, various proposals have been made in which a coated steel sheet coated with an organic coating in advance can be used to make a can without a coolant, and the inner surface is not spray-coated. Most of them involve laminating a thermoplastic solid film to a steel plate.

For example, a method of thermally laminating a biaxially stretched thermoplastic film to a metal plate directly or via an adhesive, is disclosed in JP-A-56-10451 and JP-A-57-65463. Discloses an example in which a polyester film is used as a thermoplastic film. Further, instead of a method of processing a thermoplastic resin into a film and then laminating it on a metal plate, a method of heat-melting the resin and directly extruding and laminating on the metal plate is disclosed in JP-A-51-17988. Has been done.

However, since the resin is once formed into a film, the film has to be thickened to some extent in handling,
In addition, since heating and melting and cooling are repeated, there is a problem in that it is inferior in economic efficiency as compared with the conventional coating method.

On the other hand, it has been considered to use a pre-coated steel sheet on which a paint is applied in advance, instead of a laminated steel sheet. However, a severe process of drawing and ironing is involved, so that a film that can withstand the problem cannot be obtained. There is.

[0007] For example, as a method of post-processing, Japanese Patent No. 25
No. 08799 discloses a method using a thermosetting resin, but it is a prerequisite that ironing is not added,
It is difficult to withstand drawing and ironing.

An object of the present invention is to solve the above problems and to obtain a coated metal plate for a drawn and ironed can which has excellent adhesion of the coating film to metal, is tough and has good workability, and can withstand drawing and ironing. Is.

[0009]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventors have found that the film is tough enough to withstand heat generation near 60 ° C. due to continuous drawing and ironing on the film on the inner surface of the can after processing. (Hardness), elongation and slipperiness (dynamic friction coefficient) can be maintained, and a film on the outer surface of the can after processing can have sufficient hardness even at 60 ° C on both sides of the metal plate. As a result, they have found that a coated metal plate for a can that can withstand drawing and ironing can be obtained, and have completed the present invention.

Thus, according to the present invention, a double-sided coated metal sheet having a dry coating amount of 90 to 400 mg / 100 cm @ 2 and a glass transition temperature of 5 is formed on the inner surface of the can after processing.
Under the test conditions of 0 to 120 ° C. and 60 ° C.,
The pencil hardness is H or more, the elongation is 200 to 600%, and the coefficient of dynamic friction is 0.03 to 0.25. The dry coating amount of the coating on the outer surface of the can after processing is 15 to 150 m.
There is provided a coated metal plate for a drawn and ironed can having a pencil hardness of H or higher under the test conditions of g / 100 cm 2, glass transition temperature of 50 to 120 ° C., and 60 ° C.

The present invention also provides a drawn and ironed can obtained by drawing and ironing the above-mentioned drawn and ironed can coated metal plate.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The coated metal plate of the present invention is a metal plate used for a squeezing and ironing can with coating material applied on both sides.
0-400, preferably 100-200 mg / 100c
m2, and a dry coating amount of 15 to 150, preferably 30 to 100 mg / 10, on the outer surface of the can after processing.
A film having a thickness of 0 cm2 was formed. The type of paint applied to both sides of the metal plate may be the same or different, but the required performance is usually different between the inner surface of the can and the outer surface of the can. Different is better.

First, the paint used for the inner surface of the can and the outer surface of the can will be described.

Paints for the inner surface of a can Epoxy-based paints have been conventionally used as the paints for the inner surface of a can. Epoxy paints have high hardness and good adhesion to metals, but they have the drawback of poor workability.

As a result of repeated studies on coatings suitable for this purpose, the glass transition temperature of the film obtained from the coating was 50 to 50.
120 ° C, preferably 60-100 ° C, and 60
Under the test conditions of ℃, pencil hardness H or more, elongation rate 200
-600%, preferably 250-500% and dynamic friction coefficient 0.03-0.25, preferably 0.05-0.15
It has become clear that it is suitable to be within the range. In particular, in the continuous drawing and ironing can manufacturing work, the working temperature rises to about 60 ° C. due to the heat generated during molding, and it is speculated that the importance of controlling the physical properties of the coating at 60 ° C. was shown. In addition, the conventional epoxy-based paint has a glass transition temperature of about 70 to 120 ° C. and 60 ° C.
The pencil hardness is F to 2H, the elongation is about 10 to 150%, and the dynamic friction coefficient is about 0.3 to 0.5.

Resins such as polyester resins, epoxy resins, acrylic resins, urethane resins, and resol type phenol resins, which can control the physical properties,
A combination of a curing agent such as an amino resin can be used. Among them, a polyester resin / resole type phenol resin system is particularly suitable for adjusting the characteristics of the above-mentioned film, and an epoxy resin is used as the polyester resin. A modified polyester resin such as modified or urethane modified can also be preferably used. From the above characteristics, it is suitable that the epoxy resin is partially used for adjusting the hardness of the polyester paint.

Further, regarding the polyester resin, the number average molecular weight is 10,000 to 80,000, particularly 15.0.
00-50,000, hydroxyl value 1-20, especially 2-1
2 mgKOH / g is suitable for balancing hardness and workability.

The above polyester resin is synthesized by direct esterification or transesterification of an acid component and an alcohol component.

Examples of the acid component constituting the hydroxyl group-containing polyester resin include phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, hexahydroisophthalic acid, hexahydroterephthalic acid, succinic acid, One or more dibasic acids selected from fumaric acid, adipic acid, sebacic acid, maleic anhydride, etc. and lower alkyl esterified products of these acids are mainly used. If necessary, benzoic acid, crotonic acid, pt -A monobasic acid such as butylbenzoic acid, a tribasic or higher polybasic acid such as trimellitic anhydride, methylcyclohexene tricarboxylic acid, and pyromellitic dianhydride are used in combination.

As the alcohol component constituting the above polyester resin, for example, ethylene glycol, diethylene glycol, propylene glycol, 1,3-
Butanediol, 1,4-butanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 3-methylpentanediol, 1,4-hexanediol, 1,6-hexanediol, 1,4-di A dihydric alcohol such as methylolcyclohexane is mainly used, and if necessary, a polyhydric alcohol having a valence of 3 or more such as glycerin, trimethylolethane, trimethylolpropane and pentaerythritol can be used in combination. These alcohol components may be used alone or in admixture of two or more.

When the above acid component and the above alcohol component are synthesized by a direct method such as a direct esterification method or a transesterification method, if the reaction is carried out under the condition that the carboxyl group is excessive with respect to the hydroxyl group, the carboxyl group is the main component. The polyester resin mainly containing hydroxyl groups can be obtained by carrying out the reaction under the condition that the hydroxyl groups are excessive with respect to the carboxyl groups. Further, by adding the acid anhydride to the polyester resin mainly containing the hydroxyl group, the amounts of the hydroxyl group and the carboxyl group in the single resin can be adjusted. Examples of the acid anhydride reacted with the polyester resin mainly containing a hydroxyl group include phthalic anhydride, succinic anhydride, maleic anhydride, hexahydrophthalic anhydride and trimellitic anhydride.

In the above method, the reaction by the direct esterification method or the transesterification method may be carried out under pressure or under reduced pressure, or an inert gas may be introduced to promote the reaction. Further, an organic metal catalyst such as di-n-butyltin oxide can be used as an esterification catalyst during the reaction.

The above-mentioned hydroxyl group-containing polyester resin is an oil-free polyester resin, an oil-modified alkyd resin, or a modified product of these resins, such as urethane-modified polyester resin, urethane-modified alkyd resin, epoxy-modified polyester resin, epoxy-modified alkyd resin. Any of these may be used, but among them, an oil-free polyester resin is preferable.

As the above-mentioned resol type phenol resin,
A phenol component and formaldehydes are heated in the presence of a reaction catalyst to cause a condensation reaction to introduce a methylol group, and a part of the methylol group of a methylolated phenol resin obtained by alkyletherification with an alcohol.

In the production of the resol type phenolic resin cross-linking agent, as the above-mentioned phenol component as a starting material,
A bifunctional phenol compound, a trifunctional phenol compound, a tetrafunctional or higher functional phenol compound, etc. can be used.

Examples of the bifunctional phenol compound used for producing the resol type phenol resin crosslinking agent include o-cresol, p-cresol, p-tert-butylphenol, p-ethylphenol, 2,3-xylenol,
Examples thereof include difunctional phenols such as 2,5-xylenol, and examples of trifunctional phenol compounds include phenol, m-cresol, m-ethylphenol, 3,5-xylenol, and m-methoxyphenol. Examples of the tetrafunctional phenol compound include bisphenol A and bisphenol F. These phenol compounds may be used alone or in combination of two or more.

The formaldehydes used for producing the resol type phenol resin include formaldehyde,
Paraformaldehyde, trioxane, etc. are mentioned, and they can be used individually or in mixture of 2 or more types.

The alcohol used for alkyl-etherifying a part of the methylol group of the methylolated phenol resin has 1 to 8 carbon atoms, preferably 1 to 8 carbon atoms.
Four monohydric alcohols can be preferably used.
Suitable monohydric alcohols include methanol, ethanol, n-propanol, n-butanol, isobutanol and the like.

The resol-type phenol resin has an average of 0.5 or more alkoxymethyl groups per benzene nucleus, preferably 0.6 to 3 in terms of reactivity with the hydroxyl group-containing polyester resin (A). The one having 0 pieces is suitable.

In order to adjust the dynamic friction coefficient of the film obtained from the paint for the inner surface of the can, wax can be preferably used in addition to the above resin and curing agent.

Regarding the blending ratio of the polyester resin and the resol type phenol resin, the curability and processing are within the range of polyester resin / resole type phenol resin = 80/20 to 98/2, preferably 90/10 to 97/3. Suitable from the viewpoint of gender balance.

Examples of the wax to be added include vegetable wax, animal wax, mineral wax, petroleum wax, fatty acid ester wax, and the like. Among them, liquid wax at 60 ° C. is preferably used.

The coating used for coating the inner surface of the can is 60 ° C.
In addition to the adjustment of the dynamic friction coefficient, the use of the liquid wax has effects such that the continuity of the film and the coating property are not easily impaired during DI processing, and is suitable for the inner surface of the can. Specific examples of the wax which is liquid at 60 ° C. include plant wax, animal wax, mineral wax, and fatty acid ester wax.

As the above-mentioned plant wax, there are carnauba wax, cotton wax, wood wax and the like, as animal wax there are lanolin wax, gallow wax, beeswax and the like, and as petroleum wax there is paraffin wax and microcrystalline wax. There are wax, petrolatum, etc.,
Examples of mineral waxes include ozokerite and montan wax.

As the above fatty acid ester wax,
Fatty acid sucrose ester An esterification product of polyglycerin ether and fatty acid can be mentioned.

The amount of wax added is 0.1 to 10, preferably 1 to 5 relative to 100 parts by weight of the resin in the paint.
A range of parts by weight is suitable.

Paint for can outer surface Since the paint for can outer surface of the present invention is printed and gloss coated on it after processing, it is not required to have coating continuity after processing as much as the above paint for can inner surface. Therefore, as a coating material for the outer surface of a can, the glass transition temperature of the film obtained from the coating material is 50 to 1
20 ° C, preferably 60-100 ° C and 60 ° C
It is suitable that the pencil hardness is H or higher under the test conditions of 1., and a resin such as polyester resin, epoxy resin, acrylic resin, urethane resin is combined with a curing agent such as resol type phenol resin or amino resin. Among them, the polyester resin / amino resin system is particularly suitable for adjusting the characteristics of the above-mentioned coating, since the paint does not develop color. Resol-type phenolic resin, which is a curing agent, tends to turn yellow when the coating film is baked and cured, so be careful when using it for paints on the outer surface of cans.For example, use yellowing for silver color using aluminum pigment. Therefore, it is suitable for a method of coloring and gold color, and a method of using a resol type phenol resin in combination with an amino resin because of its excellent corrosion resistance.

As the above polyester resin, a modified polyester resin such as epoxy modified or urethane modified can also be used preferably. It is also effective to partially use an epoxy resin for improving the hardness and adhesion of the polyester paint.

Further, the polyester resin has a number average molecular weight of 10,000 to 80,000, particularly 15.0.
00-50,000, hydroxyl value 1-20, especially 2-1
2 mgKOH / g is suitable for balancing hardness and workability.

As the above polyester resin, those mentioned in the description of the paint for the inner surface of the can can be used.

Examples of the amino resin which is a curing agent include a methylolated amino resin obtained by the reaction of an aldehyde with an amino component such as melamine, urea, benzoguanamine, acetoguanamine, steroganamin, spiroguanamine and dicyandiamide. Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. Also,
The above-mentioned amino resin also includes a resin obtained by etherifying the methylolated melamine resin with one or more alcohols. Examples of the alcohol used for etherification include methyl alcohol, ethyl alcohol,
n-propyl alcohol, isopropyl alcohol, n
Examples include monohydric alcohols such as butyl alcohol, isobutyl alcohol, 2-ethylbutanol, and 2-ethylhexanol. Of these, at least a part of the methylol group of the methylolated melamine resin is C1.
Melamine resins formed by etherification with a monohydric alcohol of 4 to 4 are preferable.

Specific examples of the melamine resin include Cymel 300, 303, 325, 327, 350, 730, 736, and 738 (all manufactured by Mitsui Cytec Co., Ltd.), Melan 522, 523 (all from Hitachi Chemical Co., Ltd.), Nikarac MS001,
Same MX430, same MX650 (above, all manufactured by Sanwa Chemical Co., Ltd.), Sumimar M-55, same M-100, same M
-40S (all manufactured by Sumitomo Chemical Co., Ltd.), Regimin 7
40 and 747 (all of which are manufactured by Monsanto Co., Ltd.) and the like, methyl etherified melamine resin; Uvan 20SE,
225 (all above, all manufactured by Mitsui Chemicals, Inc.), Super Beckamine J820-60, L-117-60, L-
109-65, 47-508-60, L-118-
60, the same G821-60 (all of which are manufactured by Dainippon Ink and Chemicals, Inc.) and other butyl etherified melamine resins;
Cymel 202, 232, 266, XV-51
4, the same 1130 (all are manufactured by Mitsui Cytec Co., Ltd.), Nikarac MX45, the same MX500, the same MX60
0, the same MS35, the same MS95 (all of them are manufactured by Sanwa Chemical Co., Ltd.), the Regimin 753, the same 755 (all of them are manufactured by Monsanto Co., Ltd.), Sumimar M-66B (manufactured by Sumitomo Chemical Co., Ltd.), and other methyl ethers and butyl ethers. Examples thereof include mixed etherified melamine resins. These melamine resins can be used alone or in combination of two or more.

The mixing ratio of the polyester resin and the amino resin is polyester resin / amino resin = 80/20 to 9
The range of 8/2, preferably 90/10 to 97/3 is preferable from the viewpoint of the balance between curability and processability.

In order to prevent scratches on the film obtained from the paint for the outer surface of the can, it is effective to add a wax in addition to the above resin and curing agent.

As the wax to be added, for example, vegetable wax, animal wax, mineral wax, petroleum wax, fatty acid ester wax, fluorine wax and the like can be mentioned. Among them, solid wax at 60 ° C. It is preferably used.

The coating used for coating the outer surface of the can is 60 ° C.
The use of the solid wax in (1) has the effect of preventing damage to the coating film without causing wax breakage due to ironing. Specific examples of the solid wax at 60 ° C. include polytetrafluoroethylene wax, polyethylene wax, and oxidized polyethylene wax. Further, it is also effective to use a solid wax at 60 ° C. and a liquid wax at 60 ° C. in combination.

The amount of wax added is 0.5 to 30, preferably 1 to 1 with respect to 100 parts by weight of the resin in the paint.
A range of 0 parts by weight is suitable.

Further, it is preferable to add an epoxy resin to the system of the polyester resin and the amino resin for the purpose of improving the hardness and the adhesiveness of the external coating material. Examples of the epoxy resin include a bisphenol type epoxy resin and a novolac type epoxy resin; modified epoxy resins obtained by reacting various modifying agents with the epoxy groups or hydroxyl groups in these epoxy resins can be mentioned. Is
Low molecular weight and low viscosity are desirable, and specific examples thereof include Epicoat 828, 834, 1001, 15
4 (all above, manufactured by Yuka Shell Epoxy Co., Ltd.), Araldite AER250, 280, ECN-1273, E
PN-1179 (all manufactured by Asahi Kasei Epoxy Co., Ltd.), Epotote YD-127, YD-134, Y
Examples thereof include DF-170 and YDCN-702 (all of which are manufactured by Tohto Kasei Co., Ltd.).

The amount of the epoxy resin added in the system of the hydroxyl group-containing polymer polyester resin and the melamine resin is
A suitable range is 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the total amount of the hydroxyl group-containing polymer polyester resin and the melamine resin.

If necessary, an acid catalyst may be added to the above-mentioned paint for the inner surface of the can and the outer surface of the can in order to accelerate the curing reaction. Specific examples include acid catalysts such as paratoluene sulfonic acid, dodecylbenzene sulfonic acid, dinonylnaphthalene sulfonic acid, dinonyl naphthalene disulfonic acid, phosphoric acid, and amine neutralized products of these acids. Among them, the sulfonic acid compound or an amine neutralized product of the sulfonic acid compound is preferable.

From the viewpoint of the physical properties of the resulting coating film, the amount of the acid catalyst to be blended is the amount of acid (for example, in the case of an amine neutralized product of a sulfonic acid compound, the remaining sulfone obtained by removing the amine from this neutralized product). The amount of the acid compound) is preferably 0.1 to 5 parts by weight, preferably 0.2 to 2 parts by weight, based on 100 parts by weight of the total amount of the base resin and the curing agent.

From the viewpoint of coatability, etc., a solvent is usually added to the above-mentioned paint for the inner surface of the can and the outer surface of the can.
Further, if necessary, other resins may be blended for the purpose of modifying the coating film, and further pigments such as coloring pigments, bright pigments and extender pigments; anti-aggregating agents, leveling agents, decolorizing agents It is also possible to add additives for paints such as foaming agents.

As the solvent, those which can dissolve or disperse each component such as the above-mentioned resin, curing agent and other resin used as required can be used. Specifically, for example, toluene, xylene, high solvent can be used. Boiling point Petroleum hydrocarbons and other hydrocarbon solvents, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone and other ketone solvents, ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate and other ester solvents ,
Examples thereof include alcohol solvents such as methanol, ethanol and butanol, and ether alcohol solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and diethylene glycol monobutyl ether. These may be used alone or in admixture of two or more. Can be used.

The above-mentioned pigments are mainly added to the paint for the outer surface of the can in order to improve the design of the can. For example, titanium white pigment is used as a white coat, aluminum pigment, pearl pigment and the like. It is used for the purpose of adding a glittering pigment to give a metallic or high-class feeling.

Manufacturing Method of Coated Metal Plate Next, a manufacturing method of the coated metal plate of the present invention will be described.

The coated metal plate of the present invention is applied to the can inner surface and the can outer surface by a known coating method such as roll coater coating and spray coating on both sides of the metal sheet, and then squeezed for ironing and ironing. A coating film suitable as a steel plate can be formed. For double-sided coating, it is preferable from the viewpoint of hygiene of the inner surface of the can that the outer surface side is first coated and dried, and then the inner surface side is coated and baked.

The baking condition of the coating film is usually about 5 when the maximum temperature of the metal plate is about 90 to 300 ° C.
Second to about 30 minutes.

As the material of the coated metal plate, various surface-treated steel plates, aluminum plates, aluminum alloy plates and the like which have been conventionally used as materials for DI cans can be preferably used.

[0059]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. In the following, "part" and "%"
All are based on weight.

Synthesis of Polyester Resin Solution Synthesis Example 1 49.8 parts of terephthalic acid, 49.8 parts of isophthalic acid, 34.4 parts of hexahydroterephthalic acid, 28.adipic acid.
Charge 5 parts, neopentyl glycol 99.8 parts, trimethylolpropane 6.8 parts and polycondensation catalyst, heat,
The esterification reaction is carried out while stirring and removing the produced water, and the number average molecular weight is 24,000 and the hydroxyl value is 10 mgKOH /
g, an acid value of 1.0 mgKOH / g, and a resin having a Tg point of 60 ° C. were obtained. Methyl ethyl ketone / cyclohexanone =
It was diluted with a mixed solvent of 50/50 to obtain a polyester resin solution A-1 having a solid content of 30%.

Synthesis Example 2 37.7 parts of phthalic acid, 66.4 parts of isophthalic acid, 46.2 parts of hexahydrophthalic acid, 6.7 parts of trimellitic acid,
Charge 12.4 parts of ethylene glycol, 78.8 parts of neopentyl glycol, 6.8 parts of trimethylolpropane, and a polycondensation catalyst, heat and stir them to carry out an esterification reaction while removing water produced, and a number average molecular weight. 15,000
0, hydroxyl value 5.0 mgKOH / g, acid value 2.0 mgKOH / g, T
A resin having a g point of 80 ° C. was obtained. The obtained resin was diluted with a mixed solvent of methyl ethyl ketone / cyclohexanone = 50/50 to obtain a polyester resin solution A-2 having a solid content of 30%.

Synthesis Example 3 (for Comparative Example) Polyester resin "Byron 103" manufactured by Toyobo Co., Ltd.
(Number average molecular weight 22,000, hydroxyl value 5 mgKOH / g, acid value 2 mgKOH / g or less, Tg point 45 ° C.) are diluted with a mixed solvent of methyl ethyl ketone / cyclohexanone = 50/50 to obtain a polyester resin solution A having a solid content of 30%. -3 was obtained.

Synthesis Example 4 (for Comparative Example) Polyester resin “Unitika Elitel UE-3300” manufactured by Unitika Ltd. (number average molecular weight 8,000, hydroxyl value 18 mgKOH / g, acid value 1 mgKOH / g or less, Tg point 45 ° C.) Was diluted with a mixed solvent of methyl ethyl ketone / cyclohexanone = 50/50 to obtain a polyester resin solution A-4 having a solid content of 30%.

Manufacture of Paints for Inner and Outer Surfaces Manufacturing Examples 1 to 15 Paints for inner surfaces and paints for outer surfaces were prepared according to the formulations shown in Table 1 below. In addition, Manufacturing Examples 10 to 15 are prepared for Comparative Examples.

The formulations in Table 1 are shown by solid content weight.

[0066]

[Table 1]

Preparation of Painted Metal Plates Examples 1 to 10 and Comparative Examples 1 to 9 Using the inner surface coating material and the outer surface coating material obtained in the above production examples,
Each coated metal plate was created with the combinations shown in Table 3 below. In the coated metal plate, a 0.28 mm-thick # 3004 aluminum material that had been subjected to phosphoric acid chromate treatment was used as the material. First, the outer coating material was applied to a bar coater so that each dry coating amount shown in Table 3 was obtained. Painted at 100 ℃ 60
After baking and drying for 2 seconds, the inner surface paint is applied on the opposite side of the material with a bar coater so that each dry coating amount shown in Table 3 is obtained.
It was created by baking for 2 seconds.

Tests were carried out according to the following test methods for the performance of coating films obtained from each inner surface coating material and each outer surface coating material and each coated metal plate obtained by the above method. The test results are shown in Table 3 below.

Test method Tg (° C.): A bar coater was used to coat each of the inner surface and outer surface coating materials on a tin plate so that the coating amount after drying was 180 mg / 100 cm 2, and the maximum material temperature reached was 27.
Baking was performed for 20 seconds under the condition of 0 ° C. The obtained coated plate is cut into a size of 5 mm × 5 mm, and MAC SCIE
A TMA curve was measured by a penetration method (load 1 g) using a TMA-4000 device manufactured by NCE, and the intersection of tangent lines before and after the inflection point was evaluated as Tg.

60 ° C. Elongation: Using a bar coater, the coating amount after drying each of the inner and outer coating materials was 180 mg /
It was coated on a tin plate so as to have a size of 100 cm2, and baked for 20 seconds under the condition that the maximum material reaching temperature was 270 ° C. This coating film was peeled off by the mercury amalgam method to obtain a free film. This film is cut into 5 mm width and 30 mm length, and the upper and lower 5 mm is used as a grip allowance, which is manufactured by Shimadzu Corporation.
Using an autograph AGS-H device at 60 ° C.,
The elongation rate to break was measured at a pulling speed of 500 mm / min.

60 ° C. pencil hardness: Each coated metal plate was placed on a heating plate set at 60 ° C., and the surface of the sample showed 6
After confirming that the temperature has reached 0 ° C, JIS K-5400
A pencil scratching test was conducted according to 8.4.2 (1990). The evaluation was performed by the breaking method.

60 ° C. dynamic friction coefficient: FRI manufactured by Toyo Seiki Co., Ltd.
6 heating plates for the CATION TESTER TR-2 device
Set at 0 ° C and put each coated metal plate on it. After confirming that the sample surface reached 60 ° C. with a surface thermometer, the dynamic friction coefficient was measured under the conditions of a load of 2 kg and a pulling speed of 1000 mm / min. The smaller the dynamic friction coefficient, the better the lubricity.

60 ° C. pressure-sensitive adhesiveness: 5 cm for each coated metal plate
Cut into a size of 5 cm, and apply a piece of paper (Kleenex Facial Tissue made by Crecia) to the coated surface.
s), and after applying pressure at 30 ° C./cm 2 for 24 hours in an atmosphere of 60 ° C., taking out, returning to room temperature, peeling the paper, and evaluating the state. ○: Peelable △: Peelable, but paper fibers remained in the coating film ×: Cannot be peeled off

D & I Formability: Each coated metal plate was subjected to a thin sheet deep drawing tester type 142 manufactured by Erichsen Co., Ltd., a blank diameter of 82 mm, the steps of 5 steps shown in the following table were sequentially performed, and finally the drawing rate was obtained. = 37%, ironing rate = 60
After the ironing and ironing process was carried out, the can making property, the appearance and the covering property were evaluated.

[0075]

[Table 2]

[Can making property] The following criteria were used to evaluate the rate of forming process out of 10 can forming processes. ⊚: 100% success rate. ◯: Success rate of 90% or more and less than 100%. Δ: Success rate of 50% or more and less than 90%. X: Success rate is less than 50%. [Appearance] Regarding the molded product, the condition of the processed portion was visually evaluated, and a product in which no abnormality was found in the coating film was rated as ◯. [Coverability] To 95 parts of a 2N hydrochloric acid solution, 5 parts of copper sulfate was added and dissolved, and further 100 parts of acetone was mixed to prepare a test solution. The can thus processed was dipped in this test solution for 60 seconds, washed with water and cut into a can, and the degree of corrosion on the inner surface was visually evaluated. ○: No corrosion is observed. ○ △: Corrosion is partially observed in the part of the upper part of the can that is most ironed. Δ: Corrosion is observed on almost the entire surface of the ironing portion of the can and above. X: There is a clear coating film defect and large corrosion occurs.

[0077]

[Table 3]

[0078]

EFFECTS OF THE INVENTION The double-sided coated metal sheet of the present invention has the strength and sliding property of the coating film appropriately maintained, and can withstand severe processing such as drawing and ironing, and is a precoat for DI cans. It is particularly suitable as a steel plate.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 5/00 C09D 161/10 161/10 161/20 161/20 167/00 167/00 191/06 191 / 06 B65D 1/00 B (72) Inventor Keiji Inomata 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. (72) Inventor Atsushi Shiota 4--17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Nishi Paint Co., Ltd. F term (reference) AK03C AK03H AK05C AK17C AK17H AK33B AK33C AK35C AK36 AK41B AK41C AK53C AL05B BA03 BA10B BA10C CA13C CA19B CA19C GB16 JA05B JA05C JA07B JA07C JA13B JA13C JK08B JK12B JKB 24C JN24H YY00B YY00C 4J038 BA212 DA062 DA132 DB002 DD001 DD041 GA03 KA08 MA13 MA14 NA01 NA11 PC08

Claims (7)

[Claims] 1. A double-sided coated metal plate having a dry coating amount of 90 to 400 mg / 10 on the inner surface of the can after processing.
0 cm 2, a glass transition temperature of 50 to 120 ° C., and a pencil hardness of H or more, an elongation rate of 200 to 600%, and a coefficient of dynamic friction of 0.03 to 0.25 under the test conditions of 60 ° C. The dry coating amount of the coating on the outer surface of the can after processing is 15 to 150 mg / 100 cm2, the glass transition temperature is 50 to 120 ° C, and the pencil hardness is H or more under the test condition of 60 ° C. Painted metal plate for cans. 2. The coating used to form a film on the inner surface of the can after processing has a number average molecular weight of 10,000 to 80,000.
It contains a hydroxyl group-containing high molecular weight polyester resin of 0 and a resol-type phenol resin, and the coating used to form a film on the outer surface of the can after processing has a number average molecular weight of 1
The coated metal sheet according to claim 1, which comprises a polyester resin having a hydroxyl group content of 20,000 to 80,000 and an amino resin and / or a resol-type phenol resin. 3. The coated metal sheet according to claim 1, wherein the coating material used for forming the film on the outer surface side of the can after the processing further contains an epoxy resin. 4. The coating used for forming a coating on the inner surface of a can after processing contains wax that becomes liquid at 60 ° C., and the coating used for forming a coating on the outer surface of a can after processing is 60 ° C. The coated metal plate according to any one of claims 1 to 3, wherein the coated metal plate contains a solid wax. 5. The wax which is liquid at 60 ° C. is at least one selected from fatty acid ester wax, lanolin wax, montan wax, microcrystalline wax and carnauba wax, and 60 ° C.
The coated metal plate according to any one of claims 1 to 4, wherein the solid wax is at least one selected from a fluorine-based wax and a polyolefin-based wax. 6. The coated metal plate according to claim 1, wherein the coating on the outer surface of the can after processing contains a bright pigment. 7. A drawn and ironed can obtained by drawing and ironing the coated metal plate according to any one of claims 1 to 6.