KR102374335B1 - Paint compositions, can lids, and food cans - Google Patents

Abstract

The coating composition is a polyester resin (A) having an acid value of 30 mg KOH/g or less, a glass transition temperature of 25°C or more and 40°C or less, an acid value of 30 mg KOH/g or less, a glass transition temperature of 45 to 85°C (B) and phenolic resin (C).

Description

Paint compositions, can lids, and food cans

The present invention relates to a paint composition for a can, a can lid using the same, and a food can.

Conventionally, BPA-type epoxy resins synthesized from bisphenol A (hereinafter referred to as "BPA") and epichlorohydrin as raw materials can form a coating film excellent in steam sterilization resistance (retort resistance), processability, and adhesion. Therefore, it is widely used as a paint for coating the inner and outer surfaces of cans.

However, research results have been reported that BPA has an effect of disrupting the endocrine secretion of organisms. In addition, it was mentioned as a substance in the list 67 of "chemical substances suspected of having an endocrine-disrupting action" published by the Ministry of Environment of Japan. Accordingly, there is a problem that BPA is eluted from the coating film covering the inner surface of the can to the contents. Then, the paint for cans which does not use any raw material derived from BPA at all is calculated|required.

In addition to physical properties such as flavor resistance, corrosion resistance, and retort resistance that do not impair the flavor of the contents, the paint covering the inner surface of the can is formed by molding a metal plate with a coating film on the surface of the can member. When doing so, it is necessary to have good processability of the coating film. Among the members of the can, since the lid member has a shape with many irregularities, a more complicated molding process is performed compared to the body of the can. Therefore, the coating material used for the lid member requires a high degree of workability in the formed coating film.

Furthermore, in relation to the type of contents filled in the can and the molding process of the can member, acid resistance and alkali resistance are required for the coating film, and in addition to the above physical properties, a paint satisfying acid resistance and alkali resistance is required.

In addition, beverage cans and food cans are sometimes subjected to retort treatment at a high temperature for the purpose of sterilizing the contents after filling the cans depending on the type of the contents. Therefore, when the retort resistance of the inner coating film is not sufficient, components in the coating film may be eluted into the contents during the retort treatment, which is not good for hygiene. In addition, when the retort resistance of the coating film is insufficient, the coating film component may elute into the contents even when stored at room temperature without performing retort treatment. As described above, the coating film on the inner surface of the can is required to have resistance to prevent its components from eluting into the contents. Incidentally, this property is referred to as "contaminate the contents" in the present invention.

Contamination of internal contents is usually judged by the amount of organic matter eluted from the coating film. Therefore, it is judged that the internal content contamination property is favorable, so that there is little quantity of the organic substance eluted from a coating film.

Patent Document 1 discloses a coating composition composed of a mixed polyester resin in which two types of polyester resins are mixed, a curing agent, and a curing catalyst.

[0007] Patent Document 2 discloses a coating composition including a polyester resin using a specific polyalcohol as a raw material, and a curing agent.

Patent Document 3 discloses a coating composition comprising a polyester resin, a resol-type phenol resin, and an acid catalyst.

Patent Document 1: Japanese Patent Application Laid-Open No. 2013-249376

Patent Document 2: Japanese Patent Laid-Open No. 2004-292664

Patent Document 3: Japanese Patent Laid-Open No. 2001-311042

However, the paint of Patent Document 1 is a combination of a polyester resin having a high glass transition temperature and a polyester resin having a low glass transition temperature, and while the processability is improved over time, there are problems that the contamination resistance and the alkali resistance are low. there is.

In addition, the paint of Patent Document 2 uses a polyester resin characterized by a polyalcohol of trihydric or higher, and although the content resistance of the coating film is improved, the high workability required for use in the lid member and the problem of insufficient contamination of the content there is In addition, water resistance refers to the property that the coating film is hardly adversely affected by the contents. In addition, since the coating material of Patent Document 3 uses a polyester resin having a high glass transition temperature, there is a problem of insufficient workability and alkali resistance after time has elapsed.

The present invention is to provide a coating composition capable of forming a coating film that is excellent in contamination resistance and alkali resistance and is not easily deteriorated in workability (hereinafter referred to simply as "processability") after time elapses, a can lid, and a food can for the purpose of providing do.

The coating composition of the present invention is a polyester resin (A) having an acid value of 30 mg KOH/g or less and a glass transition temperature of 25°C or more and 40°C or less, and a polyester resin having an acid value of 30 mg KOH/g or less and a glass transition temperature of 4 5 to 8 5°C (B) and a phenol resin (C).

According to the present invention, it is possible to provide a coating composition, a can lid, and a food and beverage can that can form a coating film that is excellent in stain resistance and alkali resistance, and is hardly deteriorated in workability after time has elapsed.

1A to 1C are schematic views illustrating a method of preparing a specimen for a bending workability test.

Before describing the present invention, terms are defined. Polycarboxylic acid (a) contains the carboxyl group in polycarboxylic acid, the compound esterified with monoalcohols, such as methanol and ethanol, and the acid anhydride of polycarboxylic acid.

When using the above esterified compound as polycarboxylic acid (a), "the number of carboxyl groups in polycarboxylic acid (a)" is "-COOH" and "-COOR" (R is an alkyl alcohol for esterification When used, it is an alkyl group of the alkyl alcohol used for the esterification.)

In addition, an acid anhydride group is produced|generated by the dehydration reaction of two carboxyl groups, and in this invention, one acid anhydride group is considered as two carboxyl groups. For example, trimellitic anhydride is considered a compound having three carboxyl groups. Content resistance refers to the property that the coating film is not easily affected by the contents of the can, and the contents are acidic food, salt, fish meat, etc. Acidic foods corrode iron, the material of cans, and salt oxidizes iron. Also, fish meat contains trace amounts of sulfur compounds, which react with iron and turn the can black.

It is important that the coating composition of the present invention contains a polyester resin (A) and a polyester resin (B). By containing the polyester resin (A), the coating film can have alkali resistance and excellent opening and workability. And, by including the polyester resin (B), the coating film may have internal content contamination.

In the present invention, the polyester resin (A) is a main component of the coating composition, and is synthesized by reacting the polycarboxylic acid (a) and the polyol (b). The glass transition temperature of a polyester resin (A) is 25 degreeC or more and 40 degrees C or less. The glass transition temperature can be adjusted by appropriately selecting the types of polycarboxylic acid (a) and polyol (b). In the present invention, 15-35 mol% of terephthalic acid and 55-80 mol% of isophthalic acid among 100 mol% of the total of the polycarboxylic acid (a), sebacic acid, adipic acid, and 1,4-cyclohexanedicarboxylic acid 1 to 10 mol% of one or more monomers selected from the group consisting of It is preferable that it is 5-35 mol%. When the ratio of each monomer is within such a range, a coating film having excellent content contamination resistance and alkali resistance and difficult to reduce workability can be formed by the combination of the polyester resin (B) and the phenol resin (C) described later.

Further, a more preferable aspect of the polyester resin (A) is 20-35 mol% of terephthalic acid, 60-75 mol% of isophthalic acid, sebacic acid, adipic acid and 1 in 100 mol% of the total of polycarboxylic acid (a) 1 to 6 mol% of at least one monomer selected from the group consisting of ,4-cyclohexanedicarboxylic acid, 40 to 70 mol% of 1,4-butanediol among 100 mol% of the total polyol (b), and carbon number The diol of 2 or 3 is 5-30 mol%.

Polycarboxylic acid (a) is terephthalic acid, isophthalic acid, sebacic acid, adipic acid and 1,4-cyclohexanedicarboxylic acid; aromatic dibasic acids other than these, aliphatic dibasic acids, alicyclic dibasic acids, and unsaturated dicarboxylic acids; acid anhydrides thereof; and alkyl esters thereof (eg, dimethyl terephthalic acid, diethyl terephthalic acid, dipropyl terephthalic acid).

Examples of the aromatic dibasic acid include orthophthalic acid, naphthalene dicarboxylic acid, and phenol dicarboxylic acid.

Examples of the aliphatic dibasic acid include succinic acid, acelic acid, dodecanedioic acid, and dimer acid.

Examples of the alicyclic dibasic acid include 1,3-cyclohexanedicarboxylic acid and 1,2-cyclohexanedicarboxylic acid.

Examples of the unsaturated dicarboxylic acid include fumaric acid, maleic acid, itaconic acid, and citraconic acid.

It is preferable that the polyester resin (A) has a linear structure or a branched structure. Therefore, in addition to dibasic acid, it is also good to use trifunctional or more than trifunctional acid. As an example, (anhydrous) trimellitic acid [Trimellitic acid and trimellitic anhydride are collectively described as "(anhydrous) trimellitic acid". The same applies below.] (anhydride) pyromellitic acid, ethylene glycol-bis-trimellitate anhydride, etc. are mentioned.

Moreover, you may use a monofunctional acid as needed.

In the present invention, the polyol (b) is preferably used in an amount of 40 to 80 mol% of at least 1,4-butanediol among 100 mol% of the polyol (b), more preferably 40 to 70 mol%. When 1,4-butanediol is used in an amount of 40 to 80 mol%, it is possible to form a coating film that is difficult to reduce excellent anti-contamination properties and processability, and the adhesion and corrosion resistance of the coating film are further improved.

As the polyol (b), it is preferable to use 5 to 30 mol% of a diol having 2 or 3 carbon atoms in 100 mol% of the polyol (b). Examples of the diol having 2 or 3 carbon atoms include ethylene glycol, 1,2-propanediol, and 1,3-propanediol.

As the polyol (b), in addition to 1,4-butanediol and a diol having 2 or 3 carbon atoms, an aliphatic diol having 4 to 10 carbon atoms, an alicyclic diol having 6 to 12 carbon atoms, and a diol containing an ether bond can be used.

Examples of the aliphatic diol having 4 to 10 carbon atoms include 1,2-butanediol, 1,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentane. diol, 1,9-nonanediol, 2-methyl-1,3-propanediol, and 2-ethyl-2-butyl-1,3-propanediol; and the like.

As a C6-C12 alicyclic diol, 1, 4- cyclohexane dimethanol etc. are mentioned, for example.

Examples of the diol containing an ether bond include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

Since the polyester resin may have a branched structure, in addition to the said diol, you may use trifunctional or more than trifunctional alcohol. Trimethylol propane, glycerin, trimethylol ethane, mannitol, sorbitol, pentaerythritol, methyl glucoside etc. are mentioned, for example of trifunctional or more than trifunctional alcohol.

Furthermore, you may use monofunctional alcohol as needed.

The polyester resin (A) can be synthesized by subjecting polycarboxylic acid (a) and polyol (b) to a condensation reaction or transesterification reaction at high temperature. Incidentally, when an acid anhydride is used as the polycarboxylic acid (a), some addition reactions also occur. In addition, the end point of reaction is normally determined by an acid value.

The blending ratio of the polycarboxylic acid (a) and the polyol (b) is the number of hydroxyl groups in the polyol (b) (N _B ) and the polycarboxylic acid (a) when the polycarboxylic acid (a) does not contain an esterified product. It is preferable that ratio of the number ( _NA ) of carboxyl groups is _NB / _NA = 1.10-1.40, and it is more preferable that it is 1.15-1.35.

Moreover, when polycarboxylic acid (a) contains the esterified material, it is preferable that it is _{NB/N A =} 1.10-2.40, and it is more preferable that it is 1.20-2.10.

When the ratio of _NB to _NA is within the above range, the contamination resistance of the contents is further improved, the alkali resistance is further improved, and the workability is more difficult to decrease.

5,000-30,000 are preferable and, as for the number average molecular weight of a polyester resin (A), 8,000-25,000 are more preferable. When a number average molecular weight exists in a predetermined range, workability and alkali resistance will improve more, and the solubility to the solvent of a polyester resin (A) improves more.

In addition, the number average molecular weight in this invention is the value of standard polyesterene conversion by GPC(Gel Permeation Chromatography).

The glass transition temperature of a polyester resin (A) is 25 degreeC or more and 40 degrees C or less, and 25-35 degreeC is preferable. When the glass transition temperature is within this range, by combining the polyester resin (B) and the phenol resin (C) described later, it is possible to form a coating film having excellent content contamination resistance and alkali resistance and difficult to reduce workability.

In order to improve the adhesion of the coating composition to metals and plastics and to improve the reactivity with the curing agent, the acid value may be given after the completion of the polymerization reaction of the polyester resin (A) or by a method of adding polycarboxylic anhydride during the polymerization reaction. can Examples of the polycarboxylic anhydride used for imparting an acid value include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and ethylene glycol-bis-trimellitate anhydride.

The acid value of the polyester resin (A) is 30 mg KOH/g or less, preferably 20 mg KOH/g. When the acid value is within this range, in addition to being able to form a coating film which is excellent in content contamination resistance and alkali resistance and workability is hardly reduced, acid resistance is also improved. In addition, the lower limit of an acid value is 0 mg KOH/g.

In the present invention, the polyester resin (B) is synthesized by reacting the polycarboxylic acid (a) and the polyol (b). For the polycarboxylic acid (a) and the polyol (b), the compounds exemplified in the description of the polyester resin (A) can be used. In addition to the above compound, the polyester resin (B) may use a known resin such as a resin synthesized by self-condensation of hydroxycarboxylic acid or the like.

5,000-30,000 are preferable and, as for the number average molecular weight of a polyester resin (B), 8,000-25,000 are more preferable. When a number average molecular weight exists in this range, workability and alkali resistance will improve more, and the solubility to the solvent of resin can be improved more.

The glass transition temperature of a polyester resin (B) is 45-85 degreeC, and 55-85 degreeC is preferable. When the glass transition temperature is within this range, it is possible to form a coating film having excellent content contamination resistance and alkali resistance and hardly deteriorated workability.

The acid value of the polyester resin (B) is 30 mg KOH/g or less, preferably 15 mg KOH/g. When an acid value exists in this range, it is excellent in content contamination resistance and alkali resistance, and in addition to being able to form a coating film which workability does not fall easily, acid resistance also improves. In addition, the lower limit of an acid value is 0 mg KOH/g.

As a commercial item of a polyester resin (B), For example, Toyobo Corporation's Byron 103, Byron 200, Byron 270, Byron 600, Byron GK360, Byron GK640, and Byron GK880; In addition, Eritel UE3200, Eritel UE3201, Eritel UE3203, UE3600, UE3660, Eritel UE9800 manufactured by Unityica; In addition, EVONIK's Dynapole L205, Dynapole L206, Dynapole L208, Dynapole L952; In addition, SK Chemicals' Skyborne ES100, Skyborne ES250, Skyborne ES410, Skyborne ES660, Skyborne ES901, and Skyborne ES955; and the like.

The coating composition of this invention contains a polyester resin (A), a polyester resin (B), and a phenol resin (C). It is preferable to mix|blend a polyester resin (A) and a polyester resin (B) so that the average glass transition temperature which computes a formula as follows may become 40 degreeC - 75 degreeC. When the average glass transition temperature is within this range, it is possible to form a coating film having excellent content contamination resistance and alkali resistance and difficult to reduce workability. In addition, 45-70 degreeC is better as for an average glass transition temperature.

1 Tg = W(A) Tg(A) + W(B) Tg(B)

Here, Tg is the obtained average glass transition temperature (K), Tg(A) is the glass transition temperature (K) of the polyester resin (A), and Tg(B) is the glass transition temperature (K) of the polyester resin (B) , W(A) represents the mass ratio of the polyester resin (A), and W(B) represents the mass ratio of the polyester resin (B).

The phenol resin (C) used in the present invention is a curing agent for crosslinking the polyester resin. The phenol resin can be synthesized by an addition condensation reaction between a phenol monomer and an aldehyde such as formaldehyde. Incidentally, the phenol resin (C) can be synthesized by other known methods.

The phenolic monomer is, for example, phenol, o-cresol, p-cresol, p-tert-butylphenol, p-phenylphenol, p-nonylphenol, 2,3-xylenol, 2,5-xylenol. , m-cresol, 3,5-xylenol, resorcinol, bisphenol A, bisphenol B, bisphenol E, bisphenol H, bisphenol S, catechol, and hydroquinone.

Among these, phenol, o-cresol, m-cresol, p-cresol, etc. are preferable at the point excellent in sclerosis|hardenability and reactivity, and m-cresol is more preferable.

A phenol monomer can be used individually or 2 or more types can be used together.

In addition, in a phenolic monomer, an ortho position and a para position become a reaction site with respect to a phenolic hydroxyl group. Therefore, o-cresol, p-cresol, p-tert-butylphenol, p-phenylphenol, p-nonylphenol, 2,3-xylenol, 2,5-xylenol, etc. have reactive sites in one molecule. Since there are two places, it is a phenolic monomer whose equivalent number is 2, and the functional group number is 2. Moreover, since phenol, m-cresol, 3,5-xylenol, resorcinol, etc. have 3 reactive sites in 1 molecule, it is a phenol monomer whose equivalent number is 3, and a functional group is 3. In addition, bisphenols such as bisphenol A, bisphenol F, bisphenol B, bisphenol E, bisphenol H, and bisphenol S, catechol, hydroquinone, etc. have 4 reactive sites in one molecule, so they are phenolic monomers having an equivalent number of 4. The functional group is 4. When a phenolic monomer whose equivalent number is less than 4 is used, it will be easy to obtain a phenol resin with an appropriate molecular weight. Therefore, when such a phenol resin is used for a coating material, the solubility with respect to a solvent improves and it is hard to produce the flaw derived from a phenol resin on the coating-film surface.

The phenol resin (C) is preferably a resin obtained by reacting m-cresol with an aldehyde. Since this phenol resin is excellent in sclerosis|hardenability with a polyester resin, retort resistance and alkali resistance improve more. As a commercially available phenolic resin (C), for example, Sumitomo Becklite's Sumilite Resin PR-55317 (methcresol-based phenolic resin, non-volatile content 50%), Showa Denko's Siyonol CKS-3898 (methcresol-based phenol) resin, 50% of non-volatile matter) and the like. In addition, methacresol-type phenol resin means that m-cresol is used for the raw material of a phenol resin (C).

The mass ratio of the polyester resin (polyester resin (A) + polyester resin (B)) and phenol resin (C) is preferably polyester resin/phenol resin (C) = 95/5 to 75/25, and 90/ 10-85/15 is more preferable. When the mass ratio of both is within this range, workability, retort resistance, etc. are further improved.

The coating composition of this invention can mix|blend lubricants, such as waxes, additives, such as a curing catalyst and a leveling agent, and an organic solvent, as needed for the purpose of preventing damage to the coating film in a can manufacturing process.

The wax includes animal and plant waxes such as carnauba wax, lanolin wax, palm oil, candelilla wax, and rice wax; petroleum waxes such as paraffin wax, microcrystalline wax, and petrolatam; Synthetic waxes, such as polyolefin wax and Teflon (trademark) wax, etc. are mentioned.

Examples of the curing catalyst include dodecylbenzene sulfonic acid, methane sulfonic acid, p-toluene sulfonic acid, dinonylnaphthalene sulfonic acid, trifluoromethane sulfonic acid, sulfuric acid, and phosphoric acid compounds and neutralized products thereof. .

The coating composition of the present invention can be used on both the inner and outer surfaces of a can, and it is preferable to use it as an inner paint for a can by taking advantage of its high workability, and particularly preferably for an inner paint for a member for a can lid. In addition, it cannot be overemphasized that the coating composition of this invention can be used also for the exterior coating material of the member for can lids.

The food can of the present invention is a can including a beverage can and a food can, and can contain beverages or food other than beverages as contents. And, it is preferable to provide a can lid coated with a coating film formed of the coating composition of the present invention. For food cans, a coating film (also referred to as a coating layer) is formed by coating and curing a paint for a can on the inner or outer surface of a can body made of metal or plastic. As for the said metal, metal plates, such as aluminum, a tin-plated steel plate, a chrome-treated steel plate, and a nickel-treated steel plate, etc. are mentioned, for example. The plastic may include polyolefin, polyester, and the like. As a coating method, well-known methods, such as spray coating, such as air spray, airless spray, and electrostatic spray, roll coating coating, immersion coating, and electrodeposition coating, can be used. In the case of coating on metal, it is preferably baked at a temperature of 200 to 300° C. for 10 seconds to 2 minutes, and more preferably for 20 to 40 seconds. The thickness of the coating film is usually about 1 to 30 µm.

The food can of the present invention includes a can lid and a can body. The food can is preferably a two-piece can composed of one can lid and one can body, and a three-piece can composed of two upper and lower can lids and one can body.

Among the drinks, beverages, soft drinks, coffee, tea, beer, soda water shochu, Japanese sake, whiskey, and alcoholic beverages with water are preferable. In addition, the food object of the beverage is preferably used for accommodating food such as fish meat, livestock meat, vegetables, fruit, oil, and sauce.

The can with a coating film using the coating composition of this invention can be used also for the use which accommodates non-food items, such as engine oil, a paint, and ink.

The present invention will be described in more detail below by way of Examples. In addition, "part" represents "part by mass" and "%" represents "mass %" in Examples unless otherwise specified. In addition, "Mn" represents a number average molecular weight, and "Mw" represents a mass average molecular weight, respectively.

(Measurement conditions for number average molecular weight and mass average molecular weight)

Measurements were made using Tosho's high-speed GPC apparatus 8020 series (tetrahydrofuran solvent, column temperature 40°C, polystyrene standard). Specifically, it is a measured value obtained by connecting four of Tosho's G1000HXL, G2000HXL, G3000HXL, and G4000HXL in series as a column and measuring at a flow rate of 1.0 ml/.

(Measurement conditions for glass transition temperature)

It was measured using a differential scanning calorimeter (DSC) (DSC6220 manufactured by SII) at a temperature increase rate of 10°C/min.

(Conditions for measuring acid value)

0.2 g of the polyester resin was dissolved in 20 ml of THF (tetrahydrofuran), and titrated with a 0.1 N KOH ethanol solution to determine the acid value (mg KOH/g) of the polyester resin.

Preparation example of polyester resin (A)

[Production Example (A)-1 (ester exchange method)]

In a reaction vessel, 141.6 parts of dimethyl terephthalic acid, 67.9 parts of ethylene glycol, 98.5 parts of 2-methyl-1,3-propanediol, 197.1 parts of 1,4-butanediol, 4.9 parts of trimethylolpropane, 0.1 parts of zinc acetate, 0.01 parts of titanium butoxide The transesterification reaction was performed while raising the internal temperature gradually to 220 degreeC. After distilling the theoretical amount of methanol, 460.5 parts of isophthalic acid and 29.5 parts of sebacic acid were added, it took 3 hours, and it raised to 250 degreeC gradually, and esterification was performed. Next, the atmospheric pressure in the reaction vessel was lowered to 5 mmHg or less over 30 minutes, and polymerization was performed in that state for 3 hours. Thereafter, under a nitrogen flow, the internal temperature was cooled to 200° C., and 7.0 parts of trimellitic anhydride was added, followed by reaction for 2 hours. After completion of the reaction, the reaction solution was cooled to obtain a polyester resin. The obtained resin was adjusted so that a nonvolatile matter might be 40% with the mixed solvent of Flexisolv DBE esters (made by Invista) xylene = 1/1 (mass ratio), and the resin varnish was obtained. Incidentally, the ratio of each monomer used for the above polymerization is shown in Table 1 as a molar ratio.

[Preparation Example (A)-2 (Direct polymerization method)]

123.7 parts of terephthalic acid, 470.1 parts of isophthalic acid, 30.1 parts of sebacic acid, 69.3 parts of ethylene glycol, 100.6 parts of 2-methyl-1,3-propanediol, 201.2 parts of 1,4-butanediol, 5.0 parts of trimethylolpropane, titanium 0.01 part of butoxide was put, the internal temperature was raised gradually to 250 degreeC in nitrogen atmosphere, and the esterification reaction was performed over 6 hours. Next, the atmospheric pressure in the reaction vessel was lowered to 5 mmHg or less over 30 minutes, and polymerization reaction was performed in that state for 2 hours. Thereafter, the internal temperature was cooled to 200° C. under a nitrogen flow, and 7.1 parts of trimellitic anhydride were added and reacted for 2 hours. After completion of the reaction, the reaction solution was cooled to obtain a polyester resin. The obtained resin was adjusted so that a nonvolatile matter might be 40% with the mixed solvent of Fexisolv DBE esters (made by Invista) xylene = 1/1 (mass ratio), and the resin varnish was obtained.

[Preparation Example (A)-4 (Direct polymerization method)]

116.4 parts of terephthalic acid, 436.6 parts of isophthalic acid, 35.4 parts of sebacic acid, 53.3 parts of propylene glycol, 252.5 parts of 1,4-butanediol, 101.0 parts of 1,4-cyclohexanedimethanol, 4.7 parts of trimethylolpropane, titanium butoxide 0.01 part was put, the internal temperature was raised gradually to 250 degreeC in nitrogen atmosphere, and the esterification reaction was performed over 6 hours. Next, the atmospheric pressure in the reaction vessel was lowered to 5 mmHg or less over 30 minutes, and polymerization reaction was carried out in that state for 2 hours. After completion of the reaction, the reaction solution was cooled to obtain a polyester resin. The obtained resin was adjusted so that a nonvolatile matter might be 40% with the mixed solvent of Flexisolv DBE esters (made by Invista) xylene = 1/1 (mass ratio), and the resin varnish was obtained.

[Production Examples (A)-3, (A)-5, (A)-6]

A polyester resin was synthesized in the same manner as in Production Example (A)-2 except that the raw material of Production Example (A)-2 was substituted with the raw material shown in Table 1, and Production Example (A)-3, respectively. , (A)-5, (A)-6 resin varnishes were obtained.

[Comparative Preparation Examples (A)-7 to (A)-11]

A polyester resin was synthesized in the same manner as in Production Example (A)-2 except that the raw material of Production Example (A)-2 was substituted with the raw material shown in Table 1, and Comparative Production Example (A)- A resin varnish of 7 to (A)-11 was obtained.

[Comparative Preparation Example (A)-12]

A polyester resin was synthesized in the same manner as in Production Example (A)-4 except that the raw material of Production Example (A)-4 was substituted with the raw material shown in Table 1, and Comparative Production Example (A)-2 of resin varnish was obtained.

production example Comparative Preparation Example (A)-1 (A)-2 (A)-3 (A)-4 (A)-5 (A)-6 (A)-7 (A)-8 (A)-9 (A)-10 (A)-11 (A)-12 Molar ratio of input at the time of resin synthesis polycarboxylic acid dimethyl terephthalic acid 20 terephthalic acid 20 30 20 20 30 65 50 20 28 20 20 isophthalic acid 76 76 66 75 75 65 23 80 72 76 79.5 sebacic acid 4 4 5 5 35 4 adipic acid 4 27 CHDA *1 5 20 trimellitic acid 0.5 trimellitic acid (acid addition) One One One One One One One 5 One One polyol ethylene glycol 30 30 10 35 10 30 80 20 20 30 15 propylene glycol 20 90 110 2-methyl-1,3-propanediol 30 30 35 30 20 25 30 1,4-butanediol 60 60 55 80 60 65 40 70 50 60 CHDM *2 20 20 25 20 30 TMP *3 One One One One One 0.5 2 One One One NB/ NA at the time of input 1.22 1.22 1.22 1.22 1.27 1.21 1.20 1.23 1.12 1.27 1.22 1.25 number average molecular weight 15,000 18,000 12,000 15,000 17,000 9,000 17,000 15,000 10,000 13,000 3,000 16,000 Resin acid value (mg KOH/g) 7 5 6 4 5 19 7 8 41 6 20 3 Tg (℃) 27 28 32 29 37 27 5 8 29 47 12 74

*1: 1,4-cyclohexanedicarboxylic acid

*2: 1,4-cyclohexanedimethanol

*3: Trimethylolpropane

Preparation example of polyester resin (B)

[Preparation Example (B)-1 (Direct polymerization method)]

In a reaction vessel, 172.5 parts of terephthalic acid, 402.6 parts of isophthalic acid, 43.0 parts of ethylene glycol, 202.7 parts of 2-methyl-1,3-propanediol, 174.6 parts of 1,4-cyclohexanedimethanol, 4.6 parts of trimethylolpropane, titanium butoxide 0.01 part was put, the internal temperature was gradually raised to 250 degreeC in nitrogen atmosphere, and the esterification reaction was performed for 4 hours. Next, the atmospheric pressure in the reaction vessel was lowered to 5 mmHg or less over 30 minutes, and polymerization reaction was carried out in that state for 2 hours. Thereafter, the internal temperature was cooled to 200° C. under a nitrogen flow, and 6.6 parts of trimellitic anhydride were added and reacted for 2 hours. After completion of the reaction, the reaction solution was cooled to obtain a polyester resin. The obtained resin was adjusted so that a nonvolatile matter might be 40% with the mixed solvent of Flexisolv DBE esters Invista company) xylene =1/1 (mass ratio), and the resin varnish was obtained. In addition. The ratio of each monomer used for the above polymerization is indicated in Table 2 as a molar ratio.

[Production Example (B)-2 ~ (B)-8]

A polyester resin was synthesized in the same manner as in Production Example (A)-2 except that the raw material of Production Example (B)-1 was substituted with the raw material shown in Table 2, respectively, Production Example (B)-2 ~ A resin varnish of (B)-8 was obtained.

production example Comparative Preparation Example (B)-1 (B)-2 (B)-3 (B)-4 (B)-5 (B)-6 (B)-7 (B)-8 Molar ratio of input at the time of resin synthesis polycarboxylic acid dimethyl terephthalic acid terephthalic acid 30 100 100 30 20 20 20 35 isophthalic acid 70 69 80 80 80 35 sebacic acid 30 adipic acid CHDA *1 trimellitic acid One trimellitic acid (acid addition) One One 0.5 One 4 4 7 One polyol ethylene glycol 20 20 35 30 propylene glycol 80 110 2-methyl-1,3-propanediol 65 30 85 75 25 20 50 1,4-butanediol 15 20 55 40 40 CHDM *2 35 10 15 25 40 20 TMP *3 One 0.5 0.5 One One One 0.5 NB/ NA at the time of input 1.22 1.21 1.31 1.15 1.22 1.22 1.17 1.21 number average molecular weight 18,000 15,000 20,000 9,000 17,000 4,000 16,000 14,000 Resin acid value (mg KOH/g) 7 5 3 8 22 23 38 6 Tg (℃) 60 72 81 49 52 41 55 -5

*1: 1,4-cyclohexanedicarboxylic acid

*2: 1,4-cyclohexanedimethanol

*3: Trimethylolpropane

[Example 1]

145.0 parts of the polyester resin varnish of Production Example (A)-1, 338.4 parts of the polyester resin varnish of Production Example (B)-1, and Sumilite resin PR-55317 as a phenol resin (methcresol-based phenolic resin, non-volatile content 50% of n-butanol solution of Sumitomo Vecriat Co., Ltd.) 43.1 parts, Flexisolv DBE esters (Invista Co., Ltd.) 153.4 parts as a solvent, xylene 191.1 parts, butylserosolve 23.6 parts, n-butanol 28.4 parts, cyclohexane 76.8 parts were mixed , 0.4 parts of dodecylbenzenesulfonic acid as a curing catalyst was added and mixed to obtain a paint having a nonvolatile content of 21.5%.

[Example 2]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Production Example (A)-2 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Example 3]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Production Example (A)-3 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Example 4]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Production Example (A)-4 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Example 5]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Production Example (A)-5 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Example 6]

A coating was obtained in the same manner as in Examples except that 145.0 parts of the polyester resin varnish of Production Example (A)-6 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Example 7]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Production Example (A)-2 and 338.4 parts of the polyester resin varnish of Production Example (B)-2 were used.

[Example 8]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Production Example (A)-2 and 338.4 parts of the polyester resin varnish of Production Example (B)-3 were used.

[Example 9]

A coating was obtained in the same manner as in Example 1 except that 96.7 parts of the polyester resin varnish of Production Example (A)-2 and 386.7 parts of the polyester resin varnish of Production Example (B)-4 were used.

[Example 10]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Production Example (A)-2 and 338.4 parts of the polyester resin varnish of Production Example (B)-5 were used.

[Example 11]

A coating was obtained in the same manner as in Example 1 except that 48.3 parts of the polyester resin varnish of Production Example (A)-2 and 435.1 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Example 12]

A coating was obtained in the same manner as in Example 1 except that 96.7 parts of the polyester resin varnish of Production Example (A)-2 and 386.7 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Example 13]

A paint was obtained in the same manner as in Example 1 except that 241.7 parts of the polyester resin varnish of Production Example (A)-2 and 241.7 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Example 14]

A coating was obtained in the same manner as in Example 1 except that 72.5 parts of the polyester resin varnish of Production Example (A)-2 and 410.9 parts of the polyester resin varnish of Production Example (B)-3 were used.

[Example 15]

A coating was obtained in the same manner as in Example 1 except that 193.4 parts of the polyester resin varnish of Production Example (A)-2 and 290.0 parts of the polyester resin varnish of Production Example (B)-3 were used.

[Example 16]

A coating was obtained in the same manner as in Example 1 except that 290.0 parts of the polyester resin varnish of Production Example (A)-2 and 193.4 parts of the polyester resin varnish of Production Example (B)-3 were used.

[Example 17]

A coating was obtained in the same manner as in Example 1 except that 241.7 parts of the polyester resin varnish of Production Example (A)-3 and 241.7 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Example 18]

A coating was obtained in the same manner as in Example 1 except that 241.7 parts of the polyester resin varnish of Production Example (A)-3 and 241.7 parts of the polyester resin varnish of Production Example (B)-2 were used.

[Example 19]

A coating was obtained in the same manner as in Example 1 except that 193.4 parts of the polyester resin varnish of Production Example (A)-5 and 290.0 parts of the polyester resin varnish of Production Example (B)-5 were used.

[Example 20]

A coating was obtained in the same manner as in Example 1 except that 241.7 parts of the polyester resin varnish of Production Example (A)-5 and 241.7 parts of the polyester resin varnish of Production Example (B)-4 were used.

[Example 21]

128.9 parts of polyester resin varnish of Production Example (A)-2, 300.9 parts of polyester resin varnish of Production Example (B)-1, Smilite Resin PR-55317 (methcresol-based phenolic resin, non-volatile content of 50% n- A paint was obtained in the same manner as in Example 1 except that 86.0 parts of a butanol solution (manufactured by Sumitomo Bakelite) and 201.8 parts of xylene were used.

[Example 22]

149.9 parts of polyester resin varnish of Production Example (A)-2, 349.8 parts of polyester resin varnish of Production Example (B)-1, Smilite Resin PR-55317 (methcresol-based phenolic resin, non-volatile content of 50% n- A paint was obtained in the same manner as in Example 1, except that 30.1 parts of a butanol solution (manufactured by Sumitomo Vecriat) and 187.8 parts of xylene were used.

[Comparative Example 1]

A paint was obtained in the same manner as in Example 1 except that 48.3 parts of the polyester resin varnish of Comparative Production Example (A)-7 and 435.1 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 2]

A paint was obtained in the same manner as in Example 1 except that 48.3 parts of the polyester resin varnish of Comparative Production Example (A)-8 and 435.1 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 3]

A paint was obtained in the same manner as in Example 1 except that 48.3 parts of the polyester resin varnish of Comparative Production Example (A)-9 and 435.1 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 4]

A paint was obtained in the same manner as in Example 1 except that 48.3 parts of the polyester resin varnish of Comparative Production Example (A)-10 and 435.1 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 5]

A paint was obtained in the same manner as in Example 1 except that 48.3 parts of the polyester resin varnish of Comparative Production Example (A)-11 and 435.1 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 6]

A paint was obtained in the same manner as in Example 1 except that 48.3 parts of the polyester resin varnish of Comparative Production Example (A)-12 and 435.1 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 7]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Comparative Production Example (A)-7 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 8]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Comparative Production Example (A)-8 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 9]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Comparative Production Example (A)-9 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 10]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Comparative Production Example (A)-10 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 11]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Comparative Production Example (A)-11 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 12]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Comparative Production Example (A)-12 and 338.4 parts of the polyester resin varnish of Production Example (B)-1 were used.

[Comparative Example 13]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Production Example (A)-2 and 338.4 parts of the polyester resin varnish of Comparative Production Example (B)-6 were used.

[Comparative Example 14]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Production Example (A)-2 and 338.4 parts of the polyester resin varnish of Comparative Production Example (B)-7 were used.

[Comparative Example 15]

A coating was obtained in the same manner as in Example 1 except that 145.0 parts of the polyester resin varnish of Production Example (A)-2 and 338.4 parts of the polyester resin varnish of Comparative Production Example (B)-8 were used.

[Comparative Example 16]

A paint was obtained in the same manner as in Example 1 except that 48.3 parts of the polyester resin varnish of Comparative Production Example (A)-7 and 435.1 parts of the polyester resin varnish of Production Example (B)-2 were used.

[Comparative Example 17]

A paint was obtained in the same manner as in Example 1 except that 48.3 parts of the polyester resin varnish of Comparative Production Example (A)-7 and 435.1 parts of the polyester resin varnish of Production Example (B)-3 were used.

[Comparative Example 18]

A paint was obtained in the same manner as in Example 1 except that 483.4 parts of the polyester resin varnish of Production Example (A)-6 was used and the polyester resin (B) was not used.

[Comparative Example 19]

A paint was obtained in the same manner as in Example 1 except that 483.4 parts of the polyester resin varnish of Production Example (B)-3 was used and the polyester resin (A) was not used.

[Production of test panel]

The coating materials obtained in Examples 1-22 and Comparative Examples 1-19 were coated with a bar coater on an aluminum plate having a thickness of 0.26 mm so that the dry mass might be 80 mg/dm 2 . Then, the aluminum plate was dried and cured by passing through a two-type conveyor opening having a temperature of 286° C. in the first zone and 326° C. in the second zone, thereby producing a test panel having a coating film. The obtained test panel was evaluated as follows.

<Bending workability>

A test panel was prepared in a size of 30 mm in width and 50 mm in length. Then, as shown in Fig. 1a, with the coating film of the test panel 1 outside, a round bar 2 with a diameter of 3 mm is added at a position of 30 mm in length. Then, as shown in Figure 1b, the test panel (2) was folded in two along the round bar (2) to prepare a test piece (3). Insert two aluminum plates (omitted) with a thickness of 0.26 mm between the two folded test pieces (3), and a 1 kg weight (4) of a rectangular parallelepiped measuring 15 cm in width X 5 cm in height X 5 cm in depth shown in Fig. 1c. It was dropped from the height of 40 cm to the bent part of the test piece 3, and was completely folded and bent. Then, after removing the aluminum plate, the bent portion of the test piece 3 was immersed in saline having a concentration of 1%. Then, 6.0V X 6 seconds was passed between the saline solution and the metal part of the flat part of the test piece 3 not immersed in the saline solution, and the current value was measured. When the workability of the coating film is insufficient, the coating film of the bent processed part is cracked, and the metal plate below it is exposed to increase the conductivity, so the current value increases.

◎: Current value less than 5 mA (good)

○ : Current value of 5 mA or more and less than 10 mA (available to use)

△: Current value of 10 mA or more and less than 20 mA (not available)

X: Current value of 20 mA or more (defective)

<Individuality test>

The test panel was prepared in a size of 50 mm in length X 50 mm in width. A sample was made by molding the shape of a typical stay on tab opening in a beverage can on the painted surface of the test panel using a press machine. Next, the aluminum plate was removed according to the shape of the opening from the side surface of the uncoated surface of the sample, and the opening was enlarged under a microscope and visually judged. If the opening is poor, the coating film tends to remain on the periphery of the opening, and the width protruding into the opening becomes large. When the opening property is good, the coating film is not visible at all in the opening, or even if it is visible, it means a state in which the protruding width is very small. As a specific determination method, the width|variety of the coating film which protruded was measured, and it evaluated by the following evaluation criteria.

◎: The maximum width of the coating film protruding from the opening is less than 100㎛ (good)

○: The maximum width of the coating film protruding from the opening is 100 μm or more and less than 200 μm (usable)

△: The maximum width of the coating film protruding from the opening is 200 μm or more and less than 400 μm (not usable)

X: The maximum width of the coating film protruding from the opening is 400 μm or more (defective)

<Retort resistance test>

In a state in which the test panel was immersed in water, retort processing was performed in a retort kiln at 125°C - 30 minutes, and the appearance of the coating film was visually evaluated.

◎: The appearance of the coating film does not change from that of the untreated film (good)

○: The appearance of the coating film was whitened very thinly (usable)

△: The appearance of the coating film was slightly whitened (unusable)

X: The appearance of the coating film whitened remarkably (defect)

Corrosion resistance was evaluated by an acid resistance test and an alkali resistance test.

< Acid resistance test >

The test panel was immersed in an aqueous solution of about pH 2 containing 2% by mass of citric acid, and the retort treatment was performed in a retort furnace at 125° C. for 30 minutes, and the appearance of the coating film was visually evaluated.

◎: The appearance of the coating film does not change from that of the untreated film (good)

○: The appearance of the coating film was whitened very thinly (usable)

△: The appearance of the coating film was slightly whitened (unusable)

X: The appearance of the coating film whitened remarkably (defect)

< Alkali resistance test >

The test panel was immersed in the aqueous solution adjusted to pH 12 using sodium hydroxide, the retort process was performed in 125 degreeC - 30 minutes in a retort kiln, and the external appearance of the coating film was evaluated visually.

◎: The appearance of the coating film does not change from that of the untreated film (good)

○: The appearance of the coating film was whitened very thinly (usable)

△: The appearance of the coating film was slightly whitened (unusable)

X: The appearance of the coating film whitened remarkably (defect)

<Content contamination test>

The test panel was put into a retort kiln and immersed in water. Then, a retort treatment was performed at 125° C. for 30 minutes. The ratio of the area of the test panel (area of the coating film) to water was such that the amount of water was 100 ml per 100 cm 2 of the test panel. The water after the retort treatment was analyzed using TOC-LCPH (manufactured by Shimadzu Corporation) to measure the total organic carbon (TOC) amount. Incidentally, the amount of TOC represents the total amount of organic matter present in water as the amount of carbon in the organic matter.

◎: TOC amount less than 1 ppm (good)

○: TOC amount is 1 ppm or more and less than 1.5 ppm (usable)

△: TOC amount of 1.5 ppm or more and less than 2 ppm (unusable)

X: TOC amount is 2 ppm or more (defective)

< Time-lapse machinability test>

After the test panel was left standing in a constant temperature bath at 37°C for 60 days, the panel was processed in the same manner as in the bending workability test, and the current value was measured. Then, the difference between the current value obtained in the bending workability test and the current value after the lapse of the panel time (the current value after the aging of the panel minus the current value before the lapse of the panel time) was calculated to evaluate the workability over time.

◎: The difference in current value is less than 1 mA (good)

○: Current difference between 1 mA and 5 mA (available)

△: The difference in current value is 5 mA or more and less than 10 mA (not available)

X: The difference in current value is 10 mA or more (bad)

Tables 3 and 4 show the evaluation results of the physical properties of each coating composition. In the coating composition composition in the table, the polyester resin represents the blending ratio of the polyester resin (A) and the polyester resin (B) in mass ratio. In addition, the paint shows the blending portion of the polyester resin and the blending portion of the phenol resin contained in 100 parts by mass of the paint.

Item Example One 2 3 4 5 6 7 8 9 10 11 Sample composition polyester resin Polyester resin (A) resin species (A)-1 (A)-2 (A)-3 (A)-4 (A)-5 (A)-6 (A)-2 (A)-2 (A)-2 (A)-2 (A)-2 Mixing ratio (%) 30 30 30 30 30 30 30 30 20 30 10 Polyester resin (B) resin species (B)-1 (B)-1 (B)-1 (B)-1 (B)-1 (B)-1 (B)-2 (B)-3 (B)-4 (B)-5 (B)-1 Mixing ratio (%) 70 70 70 70 70 70 70 70 80 70 90 Average glass transition temperature (℃) 49 50 51 50 53 49 58 63 45 44 56 Polyester resin ((A)+(B)) blending amount (parts) 90 90 90 90 90 90 90 90 90 90 90 Phenolic resin blending amount (parts) PR-55317 *1 10 10 10 10 10 10 10 10 10 10 10 Amount of curing catalyst (parts) DDBSA *2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 coating film bending workability ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ○ ◎ ◎ openness ◎ ◎ ◎ ○ ◎ ◎ ◎ ○ ◎ ◎ ○ retort resistance ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ◎ acid resistance ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ alkali resistance ◎ ◎ ◎ ◎ ◎ ◎ ◎ ○ ○ ○ ◎ content contamination ◎ ◎ ◎ ◎ ◎ ○ ◎ ◎ ◎ ◎ ◎ Elapsed time machinability ◎ ◎ ○ ◎ ○ ◎ ○ ○ ◎ ◎ ○

*1 Methacresol-based resol-type phenolic resin manufactured by Sumitomo Beklite Co., Ltd.

*2 Dodecylbenzenesulfonic acid

Item comparative example One 2 3 4 5 6 7 8 9 10 11 Sample composition polyester resin Polyester resin (A) resin species (A)-7 (A)-8 (A)-9 (A)-10 (A)-11 (A)-12 (A)-7 (A)-8 (A)-9 (A)-10 (A)-11 Mixing ratio (%) 10 10 10 10 10 10 30 30 30 30 30 Polyester resin (B) resin species (B)-1 (B)-1 (B)-1 (B)-1 (B)-1 (B)-1 (B)-1 (B)-1 (B)-1 (B)-1 (B)-1 Mixing ratio (%) 90 90 90 90 90 90 70 70 70 70 70 Average glass transition temperature (℃) 54 56 57 59 54 61 41 48 50 56 44 Polyester resin ((A)+(B)) blending amount (parts) 90 90 90 90 90 90 90 90 90 90 90 Phenolic resin blending amount (parts) PR-55317 *1 10 10 10 10 10 10 10 10 10 10 10 Amount of curing catalyst (parts) DDBSA *2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 coating film bending workability ◎ ○ ◎ ○ △ ◎ ◎ ◎ ◎ ○ X openness ○ △ ◎ △ ○ △ ◎ △ ◎ △ ◎ retort resistance ○ ○ △ ○ ○ ○ △ △ △ ○ △ acid resistance ○ ○ △ ○ ○ ○ △ X △ ○ △ alkali resistance △ △ △ ○ △ △ △ X X ○ X content contamination ○ △ △ ○ △ ◎ △ △ X ○ X Elapsed time machinability ○ ○ ○ △ ○ X ◎ ◎ ◎ △ △

*1 Methacresol-based resol-type phenolic resin manufactured by Sumitomo Beklite Co., Ltd.

*2 Dodecylbenzenesulfonic acid

This application claims priority based on Japanese Patent Application No. 2015-022299 filed on February 6, 2015. All contents described in the corresponding application specification and drawings are incorporated herein by reference.

1 test panel
2 round bar
3 test piece
4 weight

Claims (18)

A polyester resin (A) having an acid value of 30 mg KOH/g or less, a glass transition temperature of 25°C or more and 40°C or less, a polyester resin (B) having an acid value of 30 mg KOH/g or less, a glass transition temperature of 45 to 85°C, and a phenol resin ( C ) comprising,
The polyester resin (A) is a resin that is a reaction product of polycarboxylic acid (a) and polyol (b),
Of the total 100 mol% of the polycarboxylic acid (a), 15 to 35 mol% of terephthalic acid, 55 to 80 mol% of isophthalic acid, sebacic acid, adipic acid, and 1,4-cyclohexanedicarboxylic acid selected from the group A coating composition comprising 1 to 10 mol% of one monomer. The method according to claim 1,
A coating composition comprising 40 to 80 mol% of 1,4-butanediol and 5 to 35 mol% of a diol having 2 or 3 carbon atoms in a total of 100 mol% of the polyol (b). 3. The method according to claim 2,
The average glass transition temperature of the polyester resin (A) and the polyester resin (B) is 40 ~ 75 ℃ coating composition. 4. The method according to claim 3,
The number average molecular weight of the said polyester resin (A) is 5000-30000, and the number average molecular weight of the said polyester resin (B) is 5000-30000. 5. The method according to claim 4,
The coating composition wherein the phenol resin (C) is a resin that is a reaction product of m-cresol and an aldehyde. 4. The method according to claim 3,
The coating composition wherein the phenol resin (C) is a resin that is a reaction product of m-cresol and an aldehyde. 3. The method according to claim 2,
The number average molecular weight of the said polyester resin (A) is 5000-30000, and the number average molecular weight of the said polyester resin (B) is 5000-30000. 8. The method of claim 7,
The coating composition wherein the phenol resin (C) is a resin that is a reaction product of m-cresol and an aldehyde. 3. The method according to claim 2,
The coating composition wherein the phenol resin (C) is a resin that is a reaction product of m-cresol and an aldehyde. The method according to claim 1,
The average glass transition temperature of the polyester resin (A) and the polyester resin (B) is 40 ~ 75 ℃ coating composition. 11. The method of claim 10,
The number average molecular weight of the said polyester resin (A) is 5000-30000, and the number average molecular weight of the said polyester resin (B) is 5000-30000. 12. The method of claim 11,
The coating composition wherein the phenol resin (C) is a resin that is a reaction product of m-cresol and an aldehyde. 11. The method of claim 10,
The coating composition wherein the phenol resin (C) is a resin that is a reaction product of m-cresol and an aldehyde. The method according to claim 1,
The number average molecular weight of the said polyester resin (A) is 5000-30000, and the number average molecular weight of the said polyester resin (B) is 5000-30000. 15. The method of claim 14,
The coating composition wherein the phenol resin (C) is a resin that is a reaction product of m-cresol and an aldehyde. The method according to claim 1,
The coating composition wherein the phenol resin (C) is a resin that is a reaction product of m-cresol and an aldehyde. A can lid comprising a metal or plastic and a coating layer that is a cured product of the coating composition according to any one of claims 1 to 16. A food can comprising the can lid and body according to claim 17.

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