JP7151448B2 - PAINT COMPOSITION, PAINT PARTS, AND COATING CANS - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coating composition used for forming a coating film on coated cans and the like.

Coated cans are widely used as packaging containers for beverages, foods, and the like. The inner and outer surfaces of the coated can are coated with paint. The inner coating protects the metal from the contents, and the outer coating is used to improve the appearance and prevent scratches. It is
For example, in the case of highly processed coated cans such as so-called bottle cans that have a cap and a screw part (threaded part) that can be recapped, to improve the adhesion between the metal and the coating film during processing. In some cases, a paint film is formed after forming an undercoat layer on the metal by size coating (also called white coating or anchor coating).

Patent Document 1 discloses a paint composition for the outer surface of drawn cans containing a polyester resin and a melamine resin. However, there is no mention of workability and the like when the size coating is omitted, and the physical properties are not satisfactory.

Therefore, Patent Document 2 discloses a coating composition containing two types of polyester resins having mutually different glass transition temperatures and a curing agent. Further, Patent Document 3 discloses a coating composition containing two types of polyester resins having mutually different glass transition temperatures and a resol-type phenolic resin.

JP 2007-161841 A JP 2013-249376 A JP 2015-168760 A

However, a coating film formed from a conventional coating composition has a problem that adhesion of the coating film to metal is lowered when advanced processing is performed without an undercoat layer. In addition, when a metal container (for example, a beverage can) filled with a beverage is subjected to retort treatment, if the coated can is a bottle can, the hardness of the coating film is insufficient, and the cap is difficult to open (or open). , called openability).

An object of the present invention is to provide a coating composition, a coating member, and a coated can that are capable of forming a coating film that is difficult to decrease in adhesion to metal and has good opening properties even in the absence of an undercoat layer. .

The coating composition of the present invention comprises a polyester resin (A) having a number average molecular weight of 10,000 to 20,000 and a glass transition temperature of 70 to 120° C., a number average molecular weight of 5,000 to 10,000 and a glass transition temperature of 10 to 50. °C polyester resin (B), amino resin, and epoxy resin.

According to the present invention, it is possible to provide a coating composition, a coated member, and a coated can that are capable of forming a coating film that is difficult to decrease in adhesion to metals and has good opening properties even in the absence of an undercoat layer.

FIG. 1 is a schematic perspective view of the top of the coated can.

First, terms used in this specification are defined. Polyester resins are esters of polybasic acids and polyols. (Anhydrous) trimellitic acid includes trimellitic acid and trimellitic anhydride. The glass transition temperature (Tg) is a numerical value measured using a differential scanning calorimeter (DSC) (“DSC6220” manufactured by SII) at a heating rate of 10° C./min.

The coating composition of the present specification comprises a polyester resin (A) having a number average molecular weight of 10,000 to 20,000 and a glass transition temperature (hereinafter also referred to as Tg) of 70 to 120°C, a number average molecular weight of 5,000 to 10, 000 and a glass transition temperature of 10 to 50° C. polyester resin (B), amino resin, and epoxy resin.

The coating composition is preferably used by coating, for example, a metal member to form a coating film. Examples of the metal member include a plate shape and a three-dimensional shape formed by molding a plate material into a cup shape. It is preferable that the metal member is used as it is or after being formed into a metal container such as a can. The coating composition contains a polyester resin (A) with a relatively high Tg and a polyester resin (B) with a relatively low Tg to achieve both hardness and flexibility of the coating film, and in addition to the amino resin as a curing agent, By including the epoxy resin, the adhesion between the metal member and the coating film is not lowered (hereinafter simply referred to as adhesion) when advanced processing is performed without an undercoat layer, and the plug-opening property is good.

<Polyester resin (A)>
The polyester resin (A) used herein has a number average molecular weight of 10,000 to 20,000 and a glass transition temperature of 70 to 120°C. Tg is more preferably 80 to 120°C, more preferably 90 to 110°C. When the Tg is within the predetermined range, the hardness and opening property of the coating film are improved. When the number average molecular weight is within a predetermined range, adhesion is improved.
The polyester resin (A) preferably has an acid value of 0 to 50 mgKOH/g, more preferably 0 to 10 mgKOH/g. More preferably, the lower limit of the acid value exceeds 0 mgKOH/g. When the acid value is within the predetermined range, the retort resistance is further improved.

The polybasic acid, which is a raw material of the polyester resin (A), is preferably an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, an alicyclic dibasic acid, or a tri- or higher polycarboxylic acid.
Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 5-sodiumsulfoisophthalic acid, phthalic anhydride, biphenyldicarboxylic acid and the like.
Examples of aliphatic dicarboxylic acids include (anhydrous) succinic acid, fumaric acid, (anhydrous) maleic acid, adipic acid, sebacic acid, azelaic acid, hymic acid, dodecanedioic acid, dimer acid and the like.
Alicyclic dibasic acids include, for example, 1,3-cyclohexanedicarboxylic acid and 1,2-cyclohexanedicarboxylic acid.
Tri- or more functional polycarboxylic acids include, for example, (anhydrous) pyromellitic acid, ethylene glycol bistrimellitate dianhydride, and the like.
A polybasic acid can be used individually or in combination of 2 or more types.

The polyol, which is the raw material of the polyester resin (A), is preferably a dihydric alcohol or a trihydric or higher polyhydric alcohol.
Dihydric alcohols are, for example, 1,2-butylene glycol (also known as 1,2-butanediol), 1,3-butylene glycol (also known as 1,3-butanediol), 2-ethyl-1,3-hexane diols (aka octanediol), 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-hydroxycyclohexyl-methanol, 3-hydroxycyclohexyl-methanol, 4-hydroxycyclohexyl-methanol, Hydrogenated bisphenol A, hydrogenated bisphenol AP, hydrogenated bisphenol F, hydrogenated bisphenol S, hydrogenated biphenol, propylene oxide adduct of bisphenol A (2 to 8 mol), propylene oxide adduct of bisphenol F (2 to 8 molar addition), ethylene glycol, diethylene glycol, propylene glycol (also known as 1,2-propylene glycol), neopentyl glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-n -butyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,4-cyclohexane Dimethanol, 3-methyl-1,5-pentanediol, bisphenol A or bisphenol F to which ethylene oxide is added, xylene glycol, versatic acid glycidyl ester, ε-caprolactone and the like.
Examples of tri- or higher functional polyhydric alcohols include trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, mannitol, sorbitol, and α-methylglucoside.
Polyols can be used alone or in combination of two or more.

Commercially available polyester resins (A) include, for example, Vylon GK640 (Mn: 18,000, Tg: 79°C) manufactured by Toyobo Co., Ltd., Vylon 296 (Mn: 14,000, Tg: 71°C), Vylon GK880 (Mn: 18000, Tg: 84°C), Vyron GK888 (Mn: 15000, Tg: 89°C). Unitika Ltd.: Elitel UE3600 (Mn: 20000, Tg: 75°C), Elitel UE9600 (Mn: 18000, Tg: 71°C), Elitel UE9800 (Mn: 13000, Tg: 85°C), Elitel UE3690 (Mn: 14000, Tg: 90°C), Elitel UE9900 (Mn: 15000, Tg: 101°C), and the like.

<Polyester resin (B)>
The polyester resin (B) used herein has a number average molecular weight of 5,000 to 10,000 and a glass transition temperature of 10 to 50°C. Tg is more preferably 25 to 50°C. Adhesion and processability are improved when Tg is within a predetermined range. When the number average molecular weight is within the predetermined range, adhesion and workability are improved.
The polyester resin (B) preferably has an acid value of 0 to 50 mgKOH/g, more preferably 0 to 10 mgKOH/g. More preferably, the lower limit of the acid value exceeds 0 mgKOH/g. When the acid value is within the predetermined range, the retort resistance is further improved.

Polybasic acid and polyol, which are raw materials for the polyester resin (B), are preferably the compounds described for the polyester resin (A).

Commercially available polyester resins (B) include, for example, Toyobo Co., Ltd. Vylon GK130 (Mn: 7000, Tg: 15°C), Vylon GK590 (Mn: 7000, Tg: 15°C), Vylon GK680 (Mn: 6000, Tg: 10°C), Vylon GK810 (Mn: 6000, Tg: 46°C). Unitika Ltd.: Elitel UE3300 (Mn: 8000, Tg: 45°C). SK Chemicals: Skybon ES403 (Mn: 9000, Tg: 40°C), Skybon ES460M (Mn: 7000, Tg: 37°C), Skybon ES601 (Mn: 6000, Tg: 18°C), Skybon ES710 (Mn: 10000) , Tg: 37°C), Skybon ES750 (Mn: 8000, Tg: 35°C), Skybon ES812 (Mn: 8000, Tg: 22°C), Skybon ES850 (Mn: 7000, Tg: 30°C), Skybon ES900 (Mn : 8000, Tg: 22°C), Skybon ES960 (Mn: 7500, Tg: 18°C), and the like.

Polyester resin (A) and polyester resin (B) are preferably used so that the mass ratio is (A):(B) = 1:99 to 60:40, more preferably 20:80 to 40:60. preferable. When both polyester resins are used together in an appropriate range, retort resistance, opening property and processability are further improved.

<Amino resin>
An amino resin herein is a compound capable of reacting with a polyester resin and acts as a curing agent.
Amino resins are produced by adding formaldehyde or the like to some or all of the amino groups of the amino component to form N-methylol groups. Then, part or all of the obtained N-methylol groups are etherified by dehydration with alcohol to form N-alkoxymethyl groups.
Examples of amino components include urea resin, melamine resin, benzoguanamine (2,4-diamino-6-phenyl-1,3,5-triazine) resin, acetoguanamine resin, steroguanamine resin, spirguanamine resin, dicyandiamide resin, and the like. mentioned. A melamine/benzoguanamine cocondensation resin obtained by reacting melamine and benzoguanamine is also included. Among these resins, melamine/benzoguanamine cocondensation resins and benzoguanamine resins are preferable from the viewpoint of improving workability.

Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like.
The alcohol used for etherification of the N-methylol group is, for example, preferably a monoalcohol having 1 to 6 carbon atoms, more preferably methyl alcohol, ethyl alcohol, isobutyl alcohol or n-butyl alcohol. Alcohol can be used individually or in combination of 2 or more types.

An amino resin can be used individually or in combination of 2 or more types.

The amino resin is preferably used in an amount of 20 to 100 parts by mass, more preferably 20 to 80 parts by mass, and further 30 to 50 parts by mass with respect to a total of 100 parts by mass of the polyester resin (A) and the polyester resin (B). part is more preferred. When the amino resin is used within a predetermined range, the curability of the coating film can be appropriately adjusted, so that hardness and workability are further improved.

Commercially available amino resins include Cymel 303, Cymel 235, Mycoat 506 and Cymel 1123 manufactured by ALLNEX. DIC: Amidia L-105-60, Amidia L-109-65, Amidia L-110-60, Super Beccamin TD-126, Super Beccamin 15-594 and the like.

<Epoxy resin>
In this specification, the epoxy resin is a compound having an epoxy group, and acts as an adhesion imparting agent that improves the adhesion between the metal member and the coating film.
The epoxy resin preferably has a number average molecular weight of 300-1300, more preferably 350-950. When the number average molecular weight is within the predetermined range, workability and adhesion are further improved.
The epoxy resin preferably has an epoxy equivalent of 150 to 800 g/eq, more preferably 180 to 550 g/eq. When the epoxy equivalent is within the predetermined range, workability and adhesion are further improved.

Commercially available epoxy resins include JER828 (184 to 194 g/eq) and JER1001 (450 to 500 g/eq) manufactured by Mitsubishi Chemical. Nippon Steel & Sumikin Chemical Co., Ltd.: Epotato YD011 (440 to 510 g/eq), Epototo YD013 (800 to 900 g/eq). DIC: EPICLON850 (183-193 g/eq), EPICLON1050 (450-500 g/eq), EPICLON2050 (610-660 g/eq), and the like.
An epoxy resin can be used individually or in combination of 2 or more types.

The epoxy resin preferably contains 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass, with respect to 100 parts by mass in total of the polyester resin (A), polyester resin (B), and amino resin. When the epoxy resin is contained within a predetermined range, workability and adhesion are further improved.

<Curing catalyst>
The coating composition may optionally contain a curing catalyst. Curing catalysts that can appropriately adjust the curing rate include, for example, acid catalysts such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenedisulfonic acid, and phosphoric acid. Acid catalysts can also be amine-blocked compounds.
A curing catalyst can be used individually or in combination of 2 or more types.

The curing catalyst is preferably used in an amount of 0.1 to 4 parts by mass with respect to a total of 100 parts by mass of polyester resin (A), polyester resin (B), amino resin and epoxy resin.

<Lubricity imparting agent>
The coating composition may optionally contain a lubricity imparting agent.
The lubricity-imparting agent improves the lubricity of the coating film, and can, for example, suppress damage to the coating film when coated cans come into contact with each other.
Lubricity-imparting agents are preferably, for example, waxes and silicone-based lubricity-imparting agents.
Waxes include natural waxes and synthetic waxes.
Examples of natural waxes include animal waxes such as lanolin, beeswax and whale wax; plant waxes such as carnauba wax, candelilla wax and rice wax; and mineral waxes such as paraffin wax, microcrystalline wax and montan wax. .
Synthetic waxes include, for example, polyolefin waxes, fluorine waxes, and fatty acid ester waxes.
Silicone-based lubricity imparting agents include, for example, dimethylpolysiloxane and modified products thereof.
Lubricity imparting agents can be used alone or in combination of two or more.

The lubricity-imparting agent can be contained in an amount of 0.1 to 10 parts by mass in 100 parts by mass of the non-volatile matter of the coating composition.

<Organic solvent>
The coating composition can contain an organic solvent. The organic solvent can be appropriately selected in consideration of coatability and compatibility.
Organic solvents include, for example, aromatic hydrocarbons such as toluene, xylene and Solvesso; aliphatic esters such as ethyl acetate, butyl acetate and dicarboxylic acid methyl ester mixtures; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and isophorone; , butyl carbitol; alcohol ketones such as diacetone alcohol; alcohols such as isopropyl alcohol, n-butanol, amyl alcohol and n-hexanol.
An organic solvent can be used individually or in combination of 2 or more types.

<Paint composition>
The coating composition can be prepared by stirring and mixing the polyester resin (A), the polyester resin (B), the amino resin, and the epoxy resin.

The coating composition can be used as a colored coating by blending a coloring agent such as a pigment or dye, or can be used as a clear coating without a coloring agent. It can also be used as a varnish coating for imparting gloss and the like to a colored coating film formed from a colored coating.

<Painted parts>
In this specification, the coated member includes a metal member and a coating film that is a cured product of a coating composition. For ordinary coated parts, when performing advanced processing, the coating film cannot follow deformation due to processing, so an undercoat layer is essential. However, the coated member of the present invention can form a coating film with good adhesion that is difficult to peel off from the metal member even when advanced processing is performed when there is no undercoat layer. In addition, it cannot be overemphasized that the coating member includes the embodiment which has an undercoat. Similarly, the coating composition of the present invention may form a coating film on the undercoat layer.

The coating composition is applied to form a coating film. Examples of coating methods include roll coater coating and spray coating.

At the time of coating, the coating may be naturally dried, but a coating film with a higher hardness can be formed by heating (also referred to as a drying step or baking) for thermal curing. Baking may be performed in, for example, an electric oven, a far-infrared oven, a gas oven, a coil oven, or the like. Baking conditions may be heating in a temperature atmosphere of 150° C. to 240° C. for about 20 seconds to 15 minutes.

The weight of the coating film is preferably about 30 mg/100 cm ² to 100 mg/100 cm ² .

The metal member is preferably a metal plate or a metal molding.
Metal sheets include, for example, hot-drawn steel sheets, cold-rolled steel sheets, hot-dip galvanized steel sheets, electro-galvanized steel sheets, alloy-plated steel sheets, aluminum-zinc alloy-plated steel sheets, aluminum sheets, tin-plated steel sheets, stainless steel sheets, copper sheets, copper-plated steel sheets, tin Examples include free steel, nickel-plated steel plate, ultra-thin tin-plated steel plate, and chromium-treated steel plate. The metal plate may be, for example, a processed object such as an antirust treatment.

Examples of metal moldings include three-dimensional moldings such as moldings obtained by three-dimensionally molding a metal plate into the shape of a cup.

The thickness of the metal member is about 50 to 500 μm. The timing of forming the coating film on the metal molding may be before or after molding, but preferably after molding.

<Covered can>
A coated can herein includes a can body and a coating film that is a cured product of a coating composition. Coated cans are functionally used for beverage cans containing coffee, soft drinks, etc., and food cans containing fish or fruit. Needless to say, the coated can can also be used for storing non-food items such as lotion and engine oil.
The coated can is preferably a two-piece can, a three-piece can, or a so-called bottle can in terms of form. A two-piece can includes a can lid and a can body as a can body. A three-piece can includes two upper and lower can lids and one can body as a can body. The bottle-can comprises a bottle member having a removable cap and, as a can body, a screwed drinking spout 11 to which the cap shown in FIG. 1 can be attached.

The coated can is preferably produced by processing the metal member.

Among coated cans, for example, when manufacturing a bottle can, the drawing process for forming the mouth part with a screw from a cup-shaped aluminum three-dimensional molding and the screw forming process for the removable cap are highly advanced. processing is required. Therefore, conventional coated cans require an undercoat layer to maintain the adhesion of the coating film. However, in the coated can of the present specification, the adhesion of the coating film to metal is less likely to decrease even when the undercoat layer is absent. Note that coated cans include embodiments having a primer layer.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples. In the examples, "parts" indicate parts by mass, and "%" indicates mass%. In addition, the compounding quantity in a table|surface is a mass part.

<Polyester resin>
Table 1 shows the polyester resins used.

<Example 1>
5 parts of polyester resin (A)-a, 60 parts of polyester resin (B)-a, 5 parts of epoxy resin Epotato YD011, and Solvesso #150/butyl cellosolve = 1/1 are mixed in a flask equipped with a condenser and stirring blade. Heating was started while 20 parts of the solvent was charged and stirred. The material was melted while cooling as necessary so that the internal temperature did not exceed 100°C. After confirming dissolution of the material, the solution was cooled to room temperature. While stirring well at room temperature, 50 parts of amino resin Super Beccamine TD-126 (30 parts by mass of nonvolatile matter) and 0.8 parts of dodecylbenzenesulfonic acid as a catalyst (0.2 parts by mass of dodecylbenzenesulfonic acid) were added. and 1.0 part of carnauba wax were added. Finally, it was diluted with a mixed solvent of Solvesso #150/butyl cellosolve=1/1 to obtain a coating composition having a non-volatile content of 50%.

<Production of coated member 1>
The obtained coating composition was applied to a #5182 aluminum plate with a thickness of 0.28 mm using a bar coater so that the dry weight was 50 mg/100 cm ² , and the coating composition was heated in a gas oven at an internal temperature of 220°C for 1 minute. It was dried by heating. Then, it was heated and dried in a gas oven with an internal temperature of 200° C. for 3 minutes to prepare a coated member 1 .

<Pencil hardness at 25°C or 120°C>
The obtained coated member 1 was subjected to retort treatment at 130° C. for 30 minutes. After cooling to 25° C., the pencil hardness of the coating film at 25° C. was measured according to JIS K-5600 using “Uni” manufactured by Mitsubishi Pencil Co., Ltd. Evaluation criteria are as follows.
A: 4H or more. Good.
○: 2H to 3H. No practical problem.
△: F to H. Not practical.
x: HB or less. Not practical.
Separately, the pencil hardness of the coating film was measured on a hot plate set at 120° C. on the coated member which had been retorted in the same manner as described above.
A: H or more. Good.
○: HB to F; No practical problem.
Δ:B. Not practical x: 2B or less. Not practical.

<Drawing Adhesion>
As a substitute test for evaluating the adhesion between the coating film and the metal member after processing to form the mouth portion of the bottle can, a cap was produced and the following test was performed.
That is, the coated member 1 thus obtained was punched out into a circular disc having a diameter of 55 mm. The resulting disk was drawn so that the coating film was on the outside to produce a cap with a diameter of 25 mm and a depth of 18 mm. The obtained cap was subjected to retort treatment at 130° C. for 30 minutes, and the adhesion between the coating film and the metal member after treatment was evaluated according to the following criteria.
⊚: No peeling or cracking in the paint film. Good ◯: Some peeling and cracking were observed in the paint film. No practical problem.
Δ: Slightly many peelings and cracks in the paint film. Impossible for practical use x: Remarkable peeling and cracking of the coating film. impractical

<Screw workability>
In order to evaluate the workability of forming a screw in the drinking mouth of a bottle can, the following substitute test was conducted. First, a cap was prepared in the same manner as in the drawing adhesion test, and then screwed. The obtained spout portion with a screw was subjected to retort treatment at 130° C. for 30 minutes, and the adhesion between the coating film of the screw portion and the metal plate after treatment was evaluated according to the following criteria.
⊚: No peeling or cracking in the paint film. Good ◯: Some peeling and cracking were observed in the paint film. Practically no problem Δ: Peeling and cracking of the coating film are a little frequent. Impossible for practical use x: Remarkable peeling and cracking of the coating film. impractical

<Openability>
In order to evaluate the openability of the bottle-can cap, the following substitute test was conducted. The peel resistance value between the inner coating film of the cap and the outer coating film of the screw-equipped spout was measured to evaluate the opening property.
First, an inner surface coating for a cap was produced according to the following procedure. 80 parts of JER1009 (epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd.), 50 parts of TD-141-40 (phenolic resin, manufactured by DIC Corporation) (20 parts as non-volatile mass parts), butyl cellolub/ 50 parts of a mixed solvent of Anon/Swasol 1000=1/1/1 was charged and heating was started while stirring. The material was melted while cooling as necessary so that the internal temperature did not exceed 100°C. After confirming dissolution of the material, the solution was cooled to room temperature. 2.0 parts of carnauba wax was added with good stirring at room temperature. Finally, the mixture was diluted with a mixed solvent of butyl cellolub/anone/swasol 1000=1/1/1 to obtain an inner coating for a cap having a non-volatile content of 30%.
Next, the resulting cap inner surface paint was applied to a #5182 aluminum plate having a thickness of 0.28 mm with a bar coater so that the dry weight was 50 mg/100 cm ² , and dried by heating in a gas oven at an internal temperature of 200°C for 10 minutes. Then, a cap inner surface coated plate was produced. When the Tg of the coating film of the cap inner surface coating plate was measured using a thermomechanical analyzer (product name: manufactured by TMA Rigaku Co., Ltd.), Tg was 100°C.
The coated member 1 described above was used as the outer surface coating plate.
The outer coated plate and the cap inner coated plate were each subjected to retort treatment at 130° C. for 30 minutes. Next, test pieces for the inner surface and the outer surface, each having a size of 100 mm long and 100 mm wide, were prepared from both coating plates. Both test pieces were stacked so that the coating films were in contact with each other, placed on a hot press machine set at 100°C, and allowed to stand until the temperature of both coated plates reached 100°C. While maintaining the temperature at 100° C., a load of 5 kg/cm ² was applied and left for 30 minutes. After that, the superimposed test piece was taken out and cooled to 25°C.
Next, one side of the superimposed test piece is fixed to a table on which double-sided adhesive tape is pasted, a cellophane tape is pasted near the end of the other side, a clip is scratched on the cellophane tape, and the clip is attached. The resistance value was measured when the test piece was pulled by a slip tester (manufactured by Tester Sangyo Co., Ltd.) and the test piece on the clip side was peeled off from the test piece on the base side. The measurement results were evaluated according to the following criteria.
A: The peel resistance value is 0 g to less than 10 g. Good ◯: Peeling resistance value is 10 g or more and less than 30 g. Practically no problem Δ: Peeling resistance value is 30 g or more and less than 100 g. Impossible for practical use x: The peel resistance value is 100 g or more. impractical

<Examples 2 to 18, Comparative Examples 1 to 11>
Coated members of Examples 2 to 18 and Comparative Examples 1 to 11 were produced in the same manner as in Examples, except that the materials and amounts used in Example 1 were changed to those shown in the table. Next, physical properties were evaluated in the same manner as in Example 1.

The materials used in Tables 2 and 3 are shown below.
Super Beccamine TD-126: Butyl etherified benzoguanamine resin (manufactured by DIC)
Mycoat 506: Butoxymethyl etherified melamine resin (manufactured by Nihon Cytec Industries Co., Ltd.)
PR-53893A: Sumilite Resin PR-53893A metacresol resin (manufactured by Sumitomo Durez Co., Ltd.)
Epotato YD011: Bisphenol A type epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)

10 coated can 11 spout with screw

Claims (6)

a polyester resin (A) having a number average molecular weight of 10,000 to 20,000 and a glass transition temperature of 70 to 120°C, a polyester resin (B) having a number average molecular weight of 5,000 to 10,000 and a glass transition temperature of 10 to 50°C; A coating composition containing an amino resin and an epoxy resin , wherein the epoxy resin is added in an amount of 0.1 to 100 parts by mass in total of the polyester resin (A), the polyester resin (B), and the amino resin. A coating composition containing 15 parts by mass . 2. The coating composition according to claim 1, wherein the polyester resin (A) and the polyester resin (B) have a mass ratio of (A):(B)=1:99 to 60:40. 3. The coating composition according to claim 1, wherein said amino resin is contained in an amount of 20 to 100 parts by mass based on a total of 100 parts by mass of said polyester resin (A) and said polyester resin (B). A coating composition according to any one of claims 1 to 3 , wherein the amino resin is a benzoguanamine resin. A coated member comprising a metal member and a coating film that is a cured product of the coating composition according to any one of claims 1 to 4 . A coated can comprising a can body and a coating film that is a cured product of the coating composition according to any one of claims 1 to 4 .

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