Aluminium cans for filling with wine and aluminium cans filled with wine

Abstract

The present invention relates to an aluminum can filled with wine, which comprises: an aluminum can and wine enclosed in the aluminum can and containing 4.3 mg / L or less of molecular SO2 and 350 mg / L or less of chloride ions, the aluminum can including: an aluminum plate, a resin film provided on a face of the aluminum plate that becomes a can inner surface side, and an adhesive layer interposed between the aluminum plate and the resin film and bonding them; wherein the resin film includes a first resin layer as a topmost surface layer and a second resin layer containing a dimer acid copolymer polyester resin, and at least one of the resin layer constituting the resin film and the adhesive layer contains calcium carbonate.

Description

Technical Field

[0001] This invention relates to aluminum cans for filling wine and aluminum cans for filling wine. Background Technology

[0002] Sulfite is typically added to wine as an essential additive to inhibit wild yeasts during fruit juice fermentation and to regulate aging. When such wine is filled into aluminum cans, the added sulfuric acid is corrosive, which can easily cause corrosion in the cans. Furthermore, the redox reaction between sulfuric acid and aluminum can produce hydrogen sulfide, which can degrade the wine's flavor.

[0003] Some of the sulfurous acid added to wine combines with sugars, aldehydes, anthocyanins, etc., existing as "bound sulfurous acid," while the remaining sulfurous acid exists as "free sulfurous acid." Free sulfurous acid is mostly in the form of HSO3. - It exists in the form of sulfite ions, with the remainder existing as SO2 (molecular SO2). The ratio of sulfite ions to molecular SO2 varies depending on pH.

[0004] For example, Patent Document 1 discloses a method for encapsulating wine in an aluminum can, and discloses the manufacture of wine having less than 35 ppm of free sulfurous acid, less than 300 ppm of chloride and less than 800 ppm of sulfate, as well as the application of a corrosion-resistant coating to the inner surface of the aluminum can.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 03 / 029089 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In view of the above problems, the object of the present invention is to provide an aluminum can for filling wine and an aluminum can for filling wine, which is not prone to corrosion of the aluminum can and deterioration of the flavor of the wine.

[0010] Methods for solving problems

[0011] The inventors have discovered for the first time that a specific coating on the inner surface of an aluminum can, combined with a specific component of wine, solves the aforementioned problems (i.e., the corrosion problem of the aluminum can and the flavor degradation problem of the wine), thus completing the present invention.

[0012] That is, according to one aspect of the present invention, an aluminum can filled wine (aluminum canned wine) is provided, comprising:

[0013] Aluminum cans, including:

[0014] Aluminum plate,

[0015] A resin film disposed on the side of the aluminum plate that becomes the inner surface of the can, and an adhesive layer between the aluminum plate and the resin film that bonds them together;

[0016] The resin film includes a first resin layer as the outermost layer and a second resin layer containing a dimer acid copolyester resin, wherein at least one of the resin layers constituting the resin film and the adhesive layer contains calcium carbonate.

[0017] as well as

[0018] The wine, sealed in the aluminum can, contains less than 4.3 mg / L of molecular SO2 and less than 350 mg / L of chloride ions.

[0019] According to another aspect of the present invention, an aluminum can for filling wine is provided, comprising:

[0020] Aluminum plate,

[0021] The resin film disposed on the surface of the aluminum plate that becomes the inner surface of the can, and

[0022] An adhesive layer between the aluminum plate and the resin film, which bonds them together;

[0023] The resin film includes a first resin layer as the outermost layer and a second resin layer containing a dimer acid copolyester resin, wherein at least one of the resin layers constituting the resin film and the adhesive layer contains calcium carbonate.

[0024] Invention Effects

[0025] According to the present invention, aluminum cans for filling wine and aluminum cans for filling wine cans can be provided that are not prone to corrosion of aluminum cans and deterioration of the flavor of wine. Attached Figure Description

[0026] Figure 1 This is a partial cut-out side view of an example of an aluminum can used for filling wine.

[0027] Figure 2 This is a cross-sectional view showing an example of the layered structure of an aluminum can for filling wine.

[0028] Figure 3 This is a cross-sectional view showing another example of the layered structure of an aluminum can for filling wine.

[0029] Figure 4 This is a scatter plot showing the effect of molecular SO2 concentration and chloride ion concentration of wine on the suitability of aluminum cans. Detailed Implementation

[0030] The present invention will now be described, but this description is intended to illustrate the invention in detail and is not intended to limit the invention.

[0031] 1. Aluminum cans filled with wine

[0032] According to one aspect, an aluminum can-filled wine is provided, the aluminum can-filled wine comprising:

[0033] Aluminum cans, including:

[0034] Aluminum plate,

[0035] A resin film disposed on the side of the aluminum plate that becomes the inner surface of the can, and an adhesive layer between the aluminum plate and the resin film that bonds them together;

[0036] The resin film includes a first resin layer as the outermost layer and a second resin layer containing a dimer acid copolyester resin, wherein at least one of the resin layers constituting the resin film and the adhesive layer contains calcium carbonate.

[0037] as well as

[0038] The wine, sealed in the aluminum can, contains less than 4.3 mg / L of molecular SO2 and less than 350 mg / L of chloride ions.

[0039] As described above, the present invention can prevent corrosion of aluminum cans and deterioration of wine flavor by combining a specific coating (i.e., the aforementioned resin film) on the inner surface of the aluminum can with specific components of the wine (i.e., the aforementioned molecular SO2 concentration and chloride ion concentration).

[0040] Wine cans can be filled with wine by rolling the cap of another component onto the aluminum can body using a known rolling process.

[0041] The following describes a "wine" with a specific composition and an "aluminum can" with a specific coating on its inner surface.

[0042] 1-1. Wine

[0043] Wine sealed in aluminum cans contains less than 4.3 mg / L of molecular SO2 and less than 350 mg / L of chloride ions.

[0044] In this specification, "molecular SO2 concentration" refers to the value calculated by the following formula.

[0045] [Number 1]

[0046]

[0047] pKα=1.9499+a *0.0332+b * 0.01971

[0048] a = Temperature difference from 20℃ (T℃ - 20℃)

[0049] b = the difference between 10% vol. and vol. of alcohol (c% - 10%)

[0050] The values ​​of "pH", "alcohol concentration" and "free sulfurous acid concentration" used to calculate the concentration of molecular SO2 refer to the values ​​measured below.

[0051] In other words, "pH" refers to the value measured by a pH meter for wine at 20°C. "Alcohol concentration" refers to the value measured by liquid chromatography. "Free sulfurous acid concentration" refers to the value measured by the Rankine method.

[0052] The concentration of molecular SO2 in wine is 0–4.3 mg / L, preferably 1–3 mg / L, and more preferably 1–2 mg / L. When the concentration of molecular SO2 in wine exceeds 4.3 mg / L, it can easily cause corrosion of aluminum cans and deterioration of the wine's flavor.

[0053] In this specification, "chloride ion concentration" refers to the value determined by potentiometric titration.

[0054] The chloride ion concentration in wine is 0–350 mg / L, preferably 0–200 mg / L, and more preferably 0–100 mg / L. When the chloride ion concentration in wine exceeds 350 mg / L, it can easily cause corrosion of aluminum cans and deterioration of the wine's flavor.

[0055] 1-2, Aluminum Cans

[0056] Figure 1 An example of an aluminum can used for filling wine (hereinafter also simply referred to as an aluminum can). Figure 1 The aluminum can 1 shown comprises a container body 2, a bottom cover 3, and a lid (not shown). The container body 2 and the bottom cover 3 are collectively referred to as the aluminum can body. The container body 2 integrally comprises a neck 2a, a shoulder 2b, and a torso 2c. The bottom cover 3 is integrally crimped and fixed to the container body 2 to close the lower opening of the torso 2c. At the neck 2a, although not shown, a tamper-evident lid, formed by roll forming using a known capping machine, is fitted with another component in a manner that allows for resealing (re-sealing) by screwing. Figure 1 The diagram shows a three-piece bottle, but the aluminum can 1 can also be a two-piece bottle, that is, a bottle formed by the container body 2 and the bottom cover 3 as one piece.

[0057] To prevent corrosion of the aluminum can, the aluminum can 1 has a resin coating on its inner surface (i.e., the inner surface of the container body 2, the inner surface of the bottom cover 3, and the inner surface of the lid), as described below. Alternatively, the aluminum can 1 may also have a resin coating on its outer surface (i.e., the outer surface of the container body 2, the outer surface of the bottom cover 3, and the outer surface of the lid).

[0058] Specifically, the aluminum can includes: an aluminum plate, a resin film disposed on the surface of the aluminum plate that becomes the inner surface of the can, and an adhesive layer between the aluminum plate and the resin film and bonding them together.

[0059] The resin film comprises a first resin layer as the outermost layer and a second resin layer containing a dimer acid copolyester resin.

[0060] At least one of the resin layer constituting the resin film and the adhesive layer contains calcium carbonate.

[0061] An example of the layered structure of this aluminum can is shown in Figure 2 Another example of the layered structure of this aluminum can is shown in Figure 3 .

[0062] have Figure 2 The aluminum can with the layered structure shown (hereinafter also referred to as the aluminum can of the first embodiment) includes an aluminum plate 10, a resin film 12 disposed on the surface of the aluminum plate 10 that becomes the inner surface of the can, and an adhesive layer 11 between the aluminum plate 10 and the resin film 12 and bonding them together.

[0063] The resin film 12 is a two-layer laminated film, comprising a first resin layer 12a as the outermost layer and a second resin layer 12b containing a dimer acid copolyester resin.

[0064] The adhesive layer 11 contains calcium carbonate 14.

[0065] have Figure 3 The aluminum can with the layered structure shown (hereinafter also referred to as the aluminum can of the second embodiment) includes an aluminum plate 10, a resin film 12 disposed on the surface of the aluminum plate 10 that becomes the inner surface of the can, and an adhesive layer 11 between the aluminum plate 10 and the resin film 12 and bonding them together.

[0066] The resin film 12 is a three-layer laminated film, including a first resin layer 12a as the outermost layer, a second resin layer 12b containing dimer acid copolyester resin as the middle layer, and a third resin layer 12c as the outermost layer facing the adhesive layer 11.

[0067] The adhesive layer 11 contains calcium carbonate 14.

[0068] The aluminum can of the first embodiment is the same as that of the aluminum can of the second embodiment, except that the third resin layer 12c included in the aluminum can of the second embodiment is omitted. Therefore, the aluminum can of the second embodiment will be described below.

[0069] 1-2-1, Resin film 12

[0070] In the second embodiment, the resin film 12 disposed on the surface of the aluminum plate 10 that becomes the inner surface of the can is a three-layer laminated film. As shown in the figure, the three-layer laminated film consists of a first resin layer 12a, a second resin layer 12b, and a third resin layer 12c. Specifically, the first resin layer 12a may be a resin film containing isophthalic acid copolyester resin as the main body (i.e., at a content of 50% by mass or more) containing 3 to 15 mol% isophthalic acid relative to the total acid content of the first resin layer 12a. The second resin layer 12b may be a resin film containing dimer acid copolyester resin as the main body (i.e., at a content of 50% by mass or more) containing 5 to 50 mol% dimer acid relative to the total acid content of the second resin layer 12b. The third resin layer 12c may be a resin film containing isophthalic acid copolyester resin as the main body (i.e., at a content of 50% by mass or more) containing 3 to 15 mol% isophthalic acid relative to the total acid content of the third resin layer 12c. The first resin layer 12a, the second resin layer 12b, and the third resin layer 12c each have a thickness of, for example, 3 to 10 μm. The ratio of the dimer acid in the resin film 12 to the total acid content in the entire film is preferably 3 to 30 mol%.

[0071] Because this three-layer laminated film contains dimer acid copolyester resin, the resin film 12 possesses flexibility. Using this resin film 12 results in excellent flexibility, leading to good film-forming properties. Furthermore, during the deep drawing and thinning process in can manufacturing, the film is less prone to hair breakage or scratches (edge ​​biting). Consequently, after the contents are sealed inside the can and the product is manufactured, even if dropped or subjected to external impacts (dents), the film surface will not be damaged, and corrosion of the aluminum can is less likely. In other words, the quality of the inner surface of the aluminum can is ensured.

[0072] Furthermore, the second resin layer 12b of this three-layer laminated film contains dimer acid copolyester resin, which has high-temperature adhesion but is soft and easily damaged at room temperature. However, since the second resin layer 12b is sandwiched between the first resin layer 12a and the third resin layer 12c, which respectively contain isophthalic acid copolyester resin, the ease of handling of the resin film 12 can be improved. That is, the first resin layer 12a and the third resin layer 12c are non-adhesive even at high temperatures and have relatively strong properties at room temperature. Therefore, there is no risk of malfunctions such as winding onto the high-temperature stretching rollers during film forming, nor is there any concern about damage during transport when forming aluminum cans. However, regarding the aforementioned winding onto the stretching rollers and damage during aluminum can transport, if special countermeasures such as surface treatment of the parts where these malfunctions occur or countermeasures such as reducing production speed can resolve the issues, the first resin layer 12a and the third resin layer 12c can be omitted depending on the production technology.

[0073] Although not shown in the figure, a resin film can also be provided on the surface of the aluminum plate 10 that becomes the outer surface of the can. This resin film on the outer surface can, for example, be a blend of polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) copolymer. The resin film on the outer surface can, for example, have a thickness of 5–20 μm.

[0074] 1-2-2, Adhesive layer 11

[0075] The resin film 12 described above can be bonded to the aluminum plate 10 via an adhesive layer 11. The adhesive layer 11 can be, for example, an adhesive formed from a thermosetting epoxy resin. The adhesive layer 11 is preferably free of bisphenol A (BPA) type epoxy resin. BPA type epoxy resin can be an endocrine disruptor. Therefore, being free of BPA type epoxy resin is preferred from the perspective of reliably preventing the leaching of BPA type epoxy resin into the contents of the container. To improve adhesion by being free of BPA type epoxy resin, the content ratio (mass ratio) of, for example, polyester resin and phenolic resin is preferably 10–40:0–20. The adhesive layer 11 has, for example, a thickness of 2–20 μm.

[0076] In the first and second embodiments, calcium carbonate 14 is contained in the adhesive layer 11 in particulate form. Calcium carbonate 14 acts as an acid scavenger that reacts with sulfurous acid. Therefore, calcium carbonate 14 can prevent sulfurous acid contained in the wine from passing through the resin membrane 12 to the aluminum plate 10. As a result, corrosion of the aluminum can can be prevented, or the flavor deterioration of the wine due to the generation of hydrogen sulfide from the reaction of sulfurous acid and aluminum can be prevented.

[0077] The calcium carbonate 14 particles have, for example, an average particle size of 0.01 to 4.0 μm, preferably 0.01 to 0.1 μm. The amount of calcium carbonate 14 added relative to 100 parts by weight of the binder resin can be, for example, 5 to 50 parts by weight. When the amount of calcium carbonate added is low, the aforementioned effects tend to decrease; when the amount of calcium carbonate added is high, the formability of the resin film 12 tends to decrease.

[0078] Calcium carbonate 14 is preferably contained in the binder layer 11. In this case, calcium carbonate 14 can effectively capture the sulfite contained in the wine. Besides being contained in the binder layer 11, calcium carbonate 14 may also be contained in any layer of the resin film 12. Alternatively, calcium carbonate 14 may not be contained in the binder layer 11 but may be contained in any layer of the resin film 12. In this case, it is preferable that the resin film 12 is composed of multiple layers, with calcium carbonate 14 contained in layers other than the outermost layer. When calcium carbonate 14 is contained in layers other than the outermost layer of the resin film 12, the possibility of minor defects occurring during the molding process of the aluminum can can be eliminated.

[0079] 1-2-3. Detailed description of resin film 12

[0080] The details of the resin film 12 in the second embodiment are described below.

[0081] <First resin layer 12a>

[0082] The first resin layer 12a can be, for example, a resin film containing, at a content of 50-100% by mass, 3-15 mol% isophthalic acid relative to the total acid content of the first resin layer 12a, of an isophthalic acid copolyester resin. This resin film is non-adhesive at around 130°C.

[0083] "Isophthalic acid copolyester resin" is, for example, composed of dicarboxylic acid units containing 85-97 mol% terephthalic acid, 15-3 mol% isophthalic acid, and glycol units containing more than 90 mol% ethylene glycol. That is, "isophthalic acid copolyester resin" is, for example, mainly composed of ethylene glycol terephthalate, and copolymerized from 3-15 mol% isophthalic acid. When the isophthalic acid component is copolymerized, it imparts flexibility to the film. This prevents the formation of micro-cracks on the surface during aluminum can molding.

[0084] In isophthalic acid copolyester resins, dicarboxylic acid units other than terephthalic acid and isophthalic acid components can be contained in a range of less than 10 mol% without impairing the lamination properties of the aluminum sheet or the characteristics of the aluminum can. Examples of such dicarboxylic acid units include succinic acid, adipic acid, azelaic acid, sebacic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 1,12-dodecanoic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. They can be used alone or in combination of two or more.

[0085] Furthermore, in isophthalic acid copolyester resins, diol units other than ethylene glycol can be contained in the range of less than 10 mol%. Examples of such diol units include aliphatic diols such as diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and neopentanediol, as well as alicyclic diols such as 1,4-cyclohexanediethanol and 1,4-cyclohexanediethanol. These can be used alone or in combination of two or more.

[0086] Isophthalic acid copolyester resin is obtained by esterification of the aforementioned dicarboxylic acid component and diol component using a known method. Examples of methods include: using a starting material with a methyl group added to the end of the dicarboxylic acid component, and performing a transesterification reaction with the diol component by adding a catalyst; or using an unmodified dicarboxylic acid component as a starting material and directly esterifying it with the diol component. Alternatively, commercially available isophthalic acid copolyethylene terephthalate resin can be used. Examples of commercially available products include IP121B, PIFG8, and PIFG10 (all manufactured by Bell Polyester Products). Furthermore, the limiting viscosity of the isophthalic acid copolyester resin is not particularly limited, but is preferably 0.7 to 0.9.

[0087] The aforementioned isophthalic acid copolyester resin can be used alone for film forming, or it can be used alone or in combination with other polyester resins. The other polyester resins are, for example, polyethylene terephthalate resin, polybutylene terephthalate resin, and polypropylene terephthalate resin. They can be mixed with the isophthalic acid copolyester resin at a ratio of less than 50% by mass.

[0088] <Second resin layer 12b>

[0089] The second resin layer 12b can be, for example, a resin film containing dimer acid copolyester resin at a content of 50 to 100% by mass.

[0090] "Dimer acid copolyester resin" for example

[0091] An ester oligomer (A) consisting of dicarboxylic acid units (a1) containing more than 70 mol% terephthalic acid and diol units (a2) containing more than 70 mol% ethylene glycol, with a number average molecular weight of less than 700, comprising 50–93% by mass.

[0092] Polyester polyols (B) consisting of hydrogenated dimer acid units (b1) and 1,4-butanediol units (b2) with a number average molecular weight of 1500–3000, comprising 7–50% by mass.

[0093] These are the constituent units.

[0094] [Ester oligomer (A)]

[0095] In the aforementioned dimer acid copolyester resin, the dicarboxylic acid unit (a1) contains 70 mol% or more of terephthalic acid units. It should be noted that the total amount of dicarboxylic acid units can also be terephthalic acid units. Alternatively, dicarboxylic acid components other than terephthalic acid can be contained in amounts less than 30 mol% without impairing the lamination properties of the aluminum sheet or the characteristics of the aluminum can. Examples of dicarboxylic acid components other than terephthalic acid include: isophthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 1,12-dodecanoic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc., which can be used alone or in combination of two or more. In addition, from the viewpoint of improving the dent resistance of coated aluminum cans (i.e., the property that the film will not break even if an external impact (dent) is applied and the aluminum plate is not easily corroded), isophthalic acid can be used in the range of about 1 to 30 mol%.

[0096] In the aforementioned dimer acid copolyester resin, the diol unit (a2) contains 70 mol% or more ethylene glycol units. It should be noted that the total amount of diol units can also be ethylene glycol units. Alternatively, diol components other than ethylene glycol can be contained in the range of less than 30 mol%. Examples of diol components other than ethylene glycol include: propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediethanol, etc., which can be used alone or in combination of two or more.

[0097] In the aforementioned dimer acid copolyester resin, the number average molecular weight of the ester oligomer (A) is 700 or less, preferably 300 to 700. By copolymerizing with the ester oligomer (A) having a number average molecular weight of 700 or less, the polyester polyol (B) is randomly incorporated into the polymer chain, resulting in a transparent copolyester resin. Furthermore, the obtained copolyester resin exhibits good compatibility with other resins; therefore, when melt-extruded with other resins, problems such as surge (unstable ejection) do not occur, enabling stable film formation.

[0098] On the other hand, for example, when using ester oligomers with a number-average molecular weight exceeding 700 and approaching 1000, the polymerization limit is reached in the further copolymerization reaction with polyester polyol (B), thus, for example, a high-viscosity copolyester resin with a limiting viscosity of around 0.7 to 0.9 cannot be obtained. Furthermore, when using polyesters with a number-average molecular weight exceeding 5000, although a high-molecular-weight copolyester resin can be obtained without the polymerization limit, the resulting copolyester resin has a large molecular weight of ester (A) units, thus becoming a -(A)-(B)- type block copolymer. Due to phase separation, the resin appears cloudy. Moreover, because such block copolymers lack compatibility with other resins, surge (ejection instability) occurs during melt extrusion, and there is also the problem of not being able to form sheets or films.

[0099] The ester oligomer (A) is obtained by esterification of a dicarboxylic acid component (a1) primarily composed of terephthalic acid and a diol component (a2) primarily composed of ethylene glycol, using a known method. Examples include: a method using a starting material with a methyl group added to the end of the dicarboxylic acid component (a1) and reacting it with the diol component (a2) via transesterification with a catalyst to obtain the oligomer; and a method using an unmodified dicarboxylic acid component (a1) as a starting material and directly reacting it with the diol component (a2) to obtain the oligomer.

[0100] In the manufacture of ester oligomer (A), it is preferable, for example, to add 3 to 10% by mass of a diol (ethylene glycol) relative to the total oligomer obtained after reaching a predetermined esterification rate at a reaction temperature of 230 to 250°C, and to carry out a depolymerization reaction for about 30 minutes to 1 hour while maintaining the internal temperature at 230 to 250°C. By using a diol (ethylene glycol) for depolymerization after the esterification reaction, the number-average molecular weight of the ester oligomer (A) can be adjusted to 700 or less. On the other hand, without a depolymerization reaction, under normal conditions, the number-average molecular weight of the ester oligomer exceeds 700. Alternatively, without a depolymerization reaction, by setting the molar ratio of the diol component to the dicarboxylic acid component in a high range of 1.25 to 1.60, the number-average molecular weight can also be controlled to 700 or less, but if the molar ratio of the diol component is less than 1.25, the number-average molecular weight exceeds 700.

[0101] [Polyester Polyol (B)]

[0102] In the aforementioned dimer acid copolyester resin, the dicarboxylic acid unit of the polyester polyol (B) is composed of a hydrogenated dimer acid unit (b1). A dimer acid refers to a 36-carbon dicarboxylic acid compound obtained, for example, by dimerizing an 18-carbon unsaturated fatty acid such as oleic acid or linoleic acid. A dimer acid whose residual unsaturated double bonds after dimerization are saturated by hydrogenation is a hydrogenated dimer acid, and the dicarboxylic acid unit of the polyester polyol (B) is composed of this hydrogenated dimer acid unit (b1). It should be noted that hydrogenated dimers are typically obtained as a mixture of straight-chain branched compounds, compounds with alicyclic structures, etc., and their content varies depending on the manufacturing process; however, their content is not particularly limited in this invention. Furthermore, the diol unit of the polyester polyol (B) is composed of a 1,4-butanediol unit (b2). It should be noted that the ends of the polyester polyol (B) are all hydroxyl groups derived from the 1,4-butanediol unit (b2).

[0103] The number-average molecular weight of the polyester polyol (B) is 1500–3000, preferably 1800–2500. If the number-average molecular weight is within this range, the reactivity during copolymerization is excellent, and the resulting copolyester resin also exhibits excellent performance as a coating film for metal sheets. In contrast, when the number-average molecular weight is less than 1500, although the reactivity during copolymerization is good, there is a tendency for poor dent resistance in aluminum cans containing the coating. On the other hand, when the number-average molecular weight exceeds 3000, the reactivity during copolymerization is sometimes poor, and a copolyester resin with the desired molecular weight cannot be obtained.

[0104] Polyester polyol (B) can be obtained by esterifying hydrogenated dimer acid units (b1) and 1,4-butanediol units (b2) using a known method, but the molar ratio during the reaction needs to be adjusted to make the terminals hydroxyl groups. Alternatively, commercially available products can be used as polyester polyol (B). For example, Priplast 3199 (manufactured by Kuroda) is a commercially available polyester polyol with a number-average molecular weight of 2200 formed from hydrogenated dimer acid and 1,4-butanediol. In addition, other commercially available polyester polyols include Priplast 3162, 3192, 3196, 2101, and 2104 (all manufactured by Kuroda).

[0105] [Copolyester Resin]

[0106] The aforementioned dimer acid copolyester resin can be obtained by copolymerizing 50-93% by mass of ester oligomer (A) with 7-50% by mass of polyester polyol (B). Here, the content of polyester polyol (B) in the total polymer is 7-50% by mass, preferably 15-35% by mass. When the content of polyester polyol (B) is within the above range, the copolymerization reactivity is excellent, and in particular, the dent resistance of coated aluminum cans is excellent. Furthermore, since a copolyester resin in which polyester polyol (B) is randomly incorporated into the polymer chain is obtained, the appearance is colorless and transparent or pale yellow and transparent. On the other hand, when the content of polyester polyol (B) is less than 7% by mass, the dent resistance of coated aluminum cans is poor; when the content of polyester polyol (B) exceeds 50% by mass, the copolymerization reactivity is poor, and sometimes phase separation of polyester polyol (B) occurs in the obtained copolyester resin, resulting in a cloudy appearance.

[0107] The copolymerization reaction of the ester oligomer (A) and the polyester polyol (B) can be carried out using conventionally known methods. For example, the reaction system with each component added can be gradually depressurized from atmospheric pressure to a high vacuum below 133.3 Pa, and a series of reactions can be carried out. The reaction temperature is preferably controlled between 250 and 270°C. If the temperature exceeds 270°C, viscosity reduction due to degradation may occur in the latter half of the copolymerization reaction. If the temperature is below 250°C, the copolymerization reaction may not proceed. Antimony trioxide, germanium dioxide, titanium compounds, etc., can be used as polymerization catalysts in the copolymerization reaction. Among these, titanium compounds such as tetrabutyl titanate or tetraisopropyl titanate are preferred considering reactivity, safety, and price. Furthermore, the limiting viscosity of the aforementioned dimer acid copolymer polyester resin is not particularly limited, but is preferably 0.7 to 0.9.

[0108] Another method for obtaining dimer acid copolyester resin is to carry out an esterification reaction of a dicarboxylic acid containing 50-95 mol% terephthalic acid and 50-5 mol% dimer acid with a diol containing more than 90 mol% ethylene glycol using a known method to obtain dimer acid copolyester resin.

[0109] In dimer acid copolyester resins, dicarboxylic acid units other than terephthalic acid and dimer acid components can be contained in amounts up to 10 mol% or less, for example, without impairing the lamination properties of the aluminum sheet or the characteristics of the aluminum can. Examples of such dicarboxylic acid units include isophthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyl dicarboxylic acid, 1,12-dodecanoic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. These units can be used alone or in combination of two or more.

[0110] Furthermore, in dimer acid copolyester resins, diol units other than ethylene glycol can be contained in the range of 10 mol% or less. Examples of such diol units include aliphatic diols such as diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and neopentanediol; and alicyclic diols such as 1,4-cyclohexanediethanol and 1,4-cyclohexanediethanol. These can be used alone or in combination of two or more.

[0111] The aforementioned dimer acid copolyester resin can be used alone for film forming or blended with other polyester resins. Examples of other polyester resins include polyethylene terephthalate resin, isophthalic acid copolyester resin, polybutylene terephthalate resin, and polypropylene terephthalate resin. These can be used alone or in mixtures, and can be blended at a ratio of less than 50% by mass of the dimer acid copolyester resin.

[0112] <Third resin layer 12c>

[0113] The third resin layer 12c can be, for example, a resin film containing, at a content of 50 to 100% by mass, 3 to 15 mol% isophthalic acid relative to the total acid content of the third resin layer 12c. The third resin layer 12c can have the same composition as the first resin layer 12a.

[0114] In the copolyester resins of the first resin layer 12a, the second resin layer 12b, and the third resin layer 12c, to ensure stable electrostatic adhesion to the cooling roller during melt extrusion molding, metal salts such as magnesium acetate, calcium acetate, and magnesium chloride can be added as additives. Furthermore, as an anti-blocking agent for the film roller, inert particles such as silica, alumina, calcium carbonate, and titanium dioxide can be appropriately incorporated, with the average particle size preferably being 1.0–4.0 μm. When the particle size is less than 1.0 μm, the anti-blocking effect is poor; when it is greater than 4.0 μm, particle shedding due to wear or breakage during film stretching may occur.

[0115] Furthermore, the copolyester resins of the first resin layer 12a, the second resin layer 12b, and the third resin layer 12c may also contain additives such as coloring pigments, waxes, heat stabilizers, antioxidants, and ultraviolet absorbers, as needed. As antioxidants, hindered phenolic antioxidants, phosphorus antioxidants, and sulfur antioxidants are available, with hindered phenolic antioxidants being particularly preferred. In addition, multiple combinations of these antioxidants can be added, with a preferred content of 100 to 5000 ppm.

[0116] Multilayer film

[0117] The resin film 12 can be obtained by laminating the copolyester resins of the first resin layer 12a, the second resin layer 12b, and the third resin layer 12c using a known method. For example, a method (co-extrusion lamination) can be used where the copolyester resins of the first resin layer 12a, the second resin layer 12b, and the third resin layer 12c are fed into separate extruders and co-extruded simultaneously from a single die. Alternatively, a method (extrusion lamination) can be used where, while feeding a film of the first resin layer 12a (or the third resin layer 12c) pre-manufactured by a T-die method or a blow molding method, the copolyester resin of the second resin layer 12b is melt-extruded onto its surface and cooled and cured; while feeding a film with the resulting two-layer structure, the copolyester resin of the third resin layer 12c (or the first resin layer 12a) is melt-extruded onto its surface and cooled and cured. In addition, the thickness of the resin film 12 is not particularly limited, but the total thickness of the first resin layer 12a, the second resin layer 12b, and the third resin layer 12c is preferably 9 to 30 μm.

[0118] 2. Aluminum cans for filling wine bottles

[0119] According to another aspect, an aluminum can for filling wine is provided, the aluminum can for filling wine comprising: an aluminum plate, a resin film disposed on a surface of the aluminum plate that becomes the inner surface of the can, and an adhesive layer between the aluminum plate and the resin film and bonding them together; wherein the resin film comprises a first resin layer as the outermost layer and a second resin layer containing a dimer acid copolyester resin, and at least one of the resin layer constituting the resin film and the adhesive layer contains calcium carbonate.

[0120] For details regarding the aluminum cans used for filling wine bottles, please refer to the explanation in section "1-2, Aluminum Cans" above. Because these aluminum cans have a specific resin film on their inner surface, they are excellent in preventing corrosion of the cans and flavor deterioration of the wine during filling.

[0121] The following summarizes preferred embodiments of aluminum cans for filling wine.

[0122] [1] Aluminum cans for filling wine bottles, comprising:

[0123] Aluminum plate,

[0124] The resin film disposed on the surface of the aluminum plate that becomes the inner surface of the can, and

[0125] An adhesive layer that is located between the aluminum plate and the resin film and bonds them together;

[0126] The resin film includes a first resin layer as the outermost layer and a second resin layer containing a dimer acid copolyester resin, wherein at least one of the resin layers constituting the resin film and the adhesive layer contains calcium carbonate.

[0127] [2] The aluminum can for filling wine as described in [1], wherein the resin film has a two-layer structure of the first resin layer and the second resin layer.

[0128] [3] The aluminum can for filling wine as described in [1] or [2], wherein the first resin layer contains isophthalic acid copolyester resin.

[0129] [4] Aluminum cans for filling wine as described in any one of [1] to [3], wherein the adhesive layer contains a thermosetting epoxy resin.

[0130] [5] The aluminum can for filling wine as described in [1], wherein the resin film further includes a third resin layer as the outermost layer of the surface opposite to the adhesive layer, having a three-layer structure of the first resin layer, the second resin layer and the third resin layer.

[0131] [6] The aluminum can for filling wine as described in [5], wherein the first resin layer contains isophthalic acid copolyester resin.

[0132] [7] Aluminum cans for filling wine as described in [5] or [6], wherein the adhesive layer contains a thermosetting epoxy resin.

[0133] [8] A wine filling aluminum can as described in any one of [5] to [7], wherein the third resin layer contains isophthalic acid copolyester resin.

[0134] [9] Aluminum cans filled with wine as described in any one of [1] to [8], wherein the adhesive layer contains calcium carbonate.

[0135] Example

[0136] [Example 1]

[0137] In Example 1, various wines were sealed in aluminum cans with a specific coating on the inner surface of the can for storage tests.

[0138] [Obtaining pH, alcohol concentration, free sulfite concentration, and chloride ion concentration]

[0139] pH, alcohol concentration, free sulfite concentration, and chloride ion concentration were obtained for 38 wines. pH was determined using a pH meter at 20°C. Alcohol concentration was determined by high-performance liquid chromatography (HPLC). Free sulfite concentration was determined by Rankine distillation-titer method. Chloride ion concentration was determined by potentiometric titration.

[0140] [Calculation of the concentration of molecular SO2]

[0141] Based on the obtained values ​​of pH, alcohol concentration, and free sulfurous acid concentration, the molecular SO2 concentration of each of the 38 wines was calculated according to the above formula for calculating molecular SO2 concentration.

[0142] [Sealing into the aluminum can]

[0143] Each wine is filled into an aluminum can body, and the lid of other parts is rolled up on the aluminum can body, thus creating a can-filled wine.

[0144] The aluminum cans used have Figure 1 The bottle / can structure shown has a feature on the inner surface side of the can. Figure 3 The resin coating shown has a layered structure, with a resin coating on the outer surface of the can. Specifically, the aluminum can body has, in sequence from the outer surface, an outer surface resin film, an aluminum plate 10, an adhesive layer 11, and an inner surface resin film 12 with a three-layer structure.

[0145] The three-layer inner surface resin film 12 consists of three layers: an outer layer formed of 10 mol% isophthalic acid copolymer PET resin, an intermediate layer formed of 21 mol% dimer acid copolymer PET resin, and an inner layer formed of 10 mol% isophthalic acid copolymer PET resin. The inner surface resin film 12 has a thickness of 25 μm. The outer, intermediate, and inner layers have a thickness ratio of 1:1:0.5. Additionally, the adhesive layer 11 is formed of thermosetting epoxy resin and contains calcium carbonate particles. The adhesive layer 11 has a thickness of 3 μm.

[0146] Additionally, the outer surface resin film is composed of a blend of polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) copolymerized with isophthalic acid. The outer surface resin film has a thickness of 18 μm.

[0147] The aluminum can is manufactured as follows: an inner surface resin film is prepared using a known co-extrusion film manufacturing method, an adhesive resin is coated onto the inner surface resin film, and an outer surface resin film is prepared using a known film manufacturing method. The two films are then bonded to an aluminum plate by hot pressing.

[0148] Storage and quality evaluation of canned wine (bottled wine)

[0149] Wine was filled into storage tanks, and its quality was evaluated after aging. The aging process took place for 24 months at temperatures of 5°C, 20°C, and 38°C. Quality evaluation was conducted through visual observation of corrosion and sensory evaluation.

[0150] Under all storage conditions, if no corrosion is observed and the wine's flavor does not deteriorate, the wine is evaluated as suitable for filling test aluminum tanks. Conversely, if corrosion is observed or the wine's flavor deteriorates, the wine is evaluated as unsuitable for filling test aluminum tanks.

[0151] [Determination of the upper limits for molecular SO2 concentration and chloride ion concentration]

[0152] The horizontal axis represents the concentration of SO2 molecules (mg / L), and the vertical axis represents the concentration of chloride ions (mg / L). Data for each wine is plotted. Wines with good evaluation results (i.e., wines evaluated as suitable for use in the test aluminum cans) are marked with "○", and wines with poor evaluation results (i.e., wines evaluated as unsuitable for use in the test aluminum cans) are marked with "×".

[0153] Evaluation results as follows Figure 4As shown. According to the evaluation results, when wine with a molecular SO2 concentration of less than 4.3 mg / mL and a chloride ion concentration of less than 350 mg / L is filled into the aforementioned aluminum can with a specific coating on the inner surface, it shows that no corrosion of the aluminum can or deterioration of the wine's flavor occurs during storage.

[0154] [Example 2]

[0155] In Example 2, in addition to the aluminum cans used in Example 1 (hereinafter referred to as aluminum can A), three types of wine as shown in Table 1 below were sealed into other aluminum cans (hereinafter referred to as aluminum can B) for storage tests. The storage tests were conducted as described in the section on [Storage and Quality Evaluation of Canned Wines] of Example 1.

[0156] Aluminum can B has a bottle-like structure, and has a feature on its inner surface. Figure 2 The resin coating shown has a layered structure, with a resin coating on the outer surface of the can. Specifically, the main body of aluminum can B has, in sequence from the outer surface of the can, an outer surface resin film, an aluminum plate 10, an adhesive layer 11, and a two-layer inner surface resin film 12.

[0157] The inner surface resin film 12, with its two-layer structure, consists of two layers: an outer layer formed of a blend of polybutylene terephthalate (PBT) and polyethylene terephthalate (PET), and an inner layer formed of 10 mol% isophthalic acid copolyester resin. The inner surface resin film 12 has a thickness of 20 μm. The outer and inner layers have a thickness ratio of 1:1. Additionally, the adhesive layer 11 is formed of thermosetting epoxy resin and contains calcium carbonate particles. The adhesive layer 11 has a thickness of 3 μm.

[0158] In addition, the outer surface resin film is composed of a blend of polybutylene terephthalate (PBT) and polyethylene terephthalate (PET). The outer surface resin film has a thickness of 18 μm.

[0159] The evaluation results are shown in the table below.

[0160] [Table 1]

[0161]

[0162] Wine A has a molecular SO2 concentration of 2.2 mg / L and a chloride ion concentration of 170 mg / L. Wine B has a molecular SO2 concentration of 0.8 mg / L and a chloride ion concentration of 40 mg / L. Wine C has a molecular SO2 concentration of 2.7 mg / L and a chloride ion concentration of 50 mg / L.

[0163] When wine A was stored in aluminum can A, no corrosion occurred. However, when it was stored in aluminum can B, corrosion occurred. Similarly, when wine C was stored in aluminum can A, no corrosion occurred. However, when it was stored in aluminum can B, corrosion occurred.

[0164] The results show that even if the concentration of molecular SO2 in the wine is below 4.3 mg / mL and the concentration of chloride ions in the wine is below 350 mg / L, corrosion of the aluminum can will still occur during storage if there is no specific coating on the inner surface of the aluminum can.

[0165] The results of Examples 1 and 2 show that combining a specific coating on the inner surface of an aluminum can with a specific component of the wine can prevent corrosion of the aluminum can and deterioration of the wine's flavor.

[0166] Explanation of reference numerals in the attached figures

[0167] 1…Aluminum can for filling wine, 2…Container body, 2a…Neck, 2b…Shoulder, 2c…Tortoise, 3…Bottom cover, 10…Aluminum plate, 11…Adhesive layer, 12…Resin film, 12a…First resin layer, 12b…Second resin layer, 12c…Third resin layer, 14…Calcium carbonate

Claims

1. Aluminum cans filled with wine products, comprising: Aluminum cans, including: Aluminum plate, The resin film disposed on the surface of the aluminum plate that becomes the inner surface of the can, and An adhesive layer that is located between the aluminum plate and the resin film and bonds them together; The resin film includes a first resin layer as the outermost layer and a second resin layer containing a dimer acid copolyester resin, wherein at least one of the resin layers constituting the resin film and the adhesive layer contains calcium carbonate. as well as The wine, sealed in the aluminum can, contains less than 4.3 mg / L of molecular SO2 and less than 350 mg / L of chloride ions. in, (i) The concentration of molecular SO2 refers to the value calculated by the following formula: pKα=1.9499+a * 0.0332+b * 0.01971 a = Temperature difference from 20℃ (T℃ - 20℃) b = the difference between b and 10% vol. / vol. of alcohol (c% - 10%) In this formula, the values ​​of "pH", "ethanol concentration", and "free sulfurous acid concentration" used to calculate the concentration of molecular SO2 refer to the values ​​measured as follows: "pH" refers to the value measured by a pH meter for wine at 20°C; "alcohol concentration" refers to the value measured by liquid chromatography; and "free sulfurous acid concentration" refers to the value measured by the "vapor distillation-titration method," also known as the Rankine method. (ii) "Chloride ion concentration" refers to the value determined by potentiometric titration.

2. The aluminum can filled wine product according to claim 1, wherein, The resin film has a two-layer structure consisting of the first resin layer and the second resin layer.

3. The aluminum can filled wine product according to claim 1, wherein, The first resin layer contains isophthalic acid copolyester resin.

4. The aluminum can filled wine product according to claim 1, wherein, The adhesive layer contains thermosetting epoxy resin.

5. The aluminum can filled wine product according to claim 1, wherein, The resin film further includes a third resin layer as the outermost layer opposite to the adhesive layer, and has a three-layer structure consisting of the first resin layer, the second resin layer, and the third resin layer.

6. The aluminum can filled wine product according to claim 5, wherein, The first resin layer contains isophthalic acid copolyester resin.

7. The aluminum can filled wine product according to claim 5, wherein, The adhesive layer contains thermosetting epoxy resin.

8. The aluminum can filled wine product according to claim 5, wherein, The third resin layer contains isophthalic acid copolyester resin.

9. The aluminum can filled wine article according to any one of claims 1 to 8, wherein, The adhesive layer contains calcium carbonate.

10. Aluminum cans for filling wine bottles, comprising: Aluminum plate, The resin film disposed on the surface of the aluminum plate that becomes the inner surface of the can, and An adhesive layer that is located between the aluminum plate and the resin film and bonds them together; The resin film includes a first resin layer as the outermost layer and a second resin layer containing a dimer acid copolyester resin, wherein at least one of the resin layers constituting the resin film and the adhesive layer contains calcium carbonate.

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