JP2004042619A - Method for manufacturing polyester film-coated metallic sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a polyester film-coated metallic sheet which shows excellent economy and superb plate working properties because the possibilities of a neck-in phenomenon during melt-extrusion are low and a foreign substance is hardly generated in an obtained molten resin film and a hardly deteriorated impact resistance in heating for an outer face baking finish performed for the purpose of making the appearance of a metallic can presentable after plate making and is best-suited for the metallic can receiving a hot water sterilization. <P>SOLUTION: In the manufacturing method for coating one side of the metallic sheet with a film (A) composed mainly of a crystalline polyester with a melting point of 180°C or higher and the other side with a film (B) consisting of a crystalline polyester with a melting point of 180°C or higher, the resin films (A) and (B) obtained by cooling/setting the molten resin film extruded in a laminar fashion under the state that olefin polymer flows join at both end parts of a T-die, are uniaxially stretched in a longitudinal direction, then the stretched resin films (A) and (B) are thermally set and the polyester films (A) and (B) are obtained by cutting/removing both end parts as one process. The polyester films (A) and (B) are laminated on the metallic sheet heated in a separate process as the other process. <P>COPYRIGHT: (C)2004,JPO

Description

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【表２】

【００７７】
【発明の効果】
本発明のポリエステル系フィルム被覆金属板の製造方法は原料の無駄を省けるため、経済性に優れた製造方法であるばかりでなく、フレーバー性に優れたポリエステル系フィルム被覆金属板が得られる製造方法である。さらに、製缶性（特に、缶内面樹脂膜と加工ポンチの離型性と缶外面樹脂膜の耐キズつき性）に優れ、かつ内容物を充填後に実施される温水殺菌処理で金属缶外面の外観不良（樹脂膜の白化）が発生しにくく、かつ製缶後に美麗化を目的として実施される外面焼付け塗装を想定した加熱を実施しても耐衝撃性が低下しにくいため、極めて有用なポリエステル系フィルム被覆金属板の製造方法といえる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a metal film coated with a polyester film. More specifically, the present invention relates to a method for producing a polyester film-coated metal sheet which is excellent in can-making properties (eg, drawing / ironing workability) and impact resistance, and is suitable for a metal can to be subjected to hot water sterilization. .
[0002]
[Prior art]
Conventionally, the inner surface and outer surface of metal cans are widely coated with a solution in which various thermosetting resins such as epoxy and phenol are dissolved or dispersed in a solvent to prevent corrosion. Has been done. However, this method of coating with a thermosetting resin has disadvantages in that it often takes a long time to dry the paint, resulting in a decrease in productivity and undesired problems such as environmental pollution due to a large amount of organic solvents.
[0003]
In order to solve such a drawback, a method of coating a metal plate with a thermoplastic resin by a melt extrusion method has been disclosed (for example, see Patent Document 1).
[0004]
Further, a method is disclosed in which a melt-extruded thermoplastic resin is once cooled and solidified, and then pressure-bonded to a heated metal plate (for example, see Patent Document 2). However, in these thermoplastic resin coating methods, when the molten resin is extruded in a layer form from a T-die, the width of the molten resin film greatly decreases (referred to as neck-in), and is several tens of cm with respect to the resin width required for coating. It was necessary to form a film with a wide width, and it was not a method that was satisfactory in terms of economy.
[0005]
In order to solve such a drawback, a method of reducing neck-in by using a polyester obtained by blending a polyester obtained by copolymerizing a trifunctional or higher polybasic acid or polyhydric alcohol component is disclosed (for example, See Patent Documents 3 and 4.) However, in these coating methods, a polyester obtained by copolymerizing a trifunctional or higher polybasic acid or polyhydric alcohol component is liable to be thermally degraded in a melting step from an extruder to a T-die, and even when a heat stabilizer is used in combination. Foreign matter (for example, a gel-like foreign matter or a foreign matter with a degraded substance as a nucleus) is likely to be generated in the obtained molten resin film, and a crack originating from the foreign matter is formed in the resin coating layer at the time of can-making. It was not satisfactory as a coated metal plate.
[0006]
In addition, the coating resin of the resin-coated metal plate used for drawing and ironing cans is required not only to have excellent formability that can follow can making (drawing and ironing), but also to beautify after can making. It is required that the impact resistance does not decrease even in the heating of the outer surface baking coating carried out as follows. However, the impact resistance of the resin-coated metal sheet is often lowered, and the impact resistance is not satisfied.
[0007]
[Patent Document 1]
JP-A-57-203545 [Patent Document 2]
JP-A-10-309775 [Patent Document 3]
JP-A-10-86308 [Patent Document 4]
JP 2000-71388 A
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional technology. That is, since the neck-in at the time of melt extrusion is small and foreign matters are hardly generated in the obtained molten resin film, it is excellent in economy and can making property, and external baking coating performed for the purpose of beautification after can making It is intended to provide a method for producing a polyester-film-coated metal sheet suitable for a metal can to be subjected to a hot water sterilization treatment, in which impact resistance is hardly reduced even by heating.
[0009]
[Means for Solving the Problems]
An object of the present invention is to coat a film (A) mainly composed of a crystalline polyester having a melting point of 180 ° C. or more on one surface of a metal plate and a film (B) composed of a crystalline polyester having a melting point of 180 ° C. or more on the other surface. In the manufacturing method of coating, the resin films (A) and (B) obtained by cooling and solidifying a molten resin film extruded in a layered state in a state where olefin polymers are merged at both ends using a T die are vertically oriented. The polyester film (A) and (B) are uniaxially stretched, then heat-set, and then cut and removed at both ends to obtain the polyester films (A) and (B). A method for producing a polyester-based film-coated metal plate comprising a method of laminating on a metal plate, wherein the polyester-based film (A) has a composite structure of (I) layer / (II) layer; Is composed of 60:40 to 30:70 (% by weight) of polyethylene terephthalate and polybutylene phthalate. In the (II) layer, 50 mol% or more of the total acid component is a terephthalic acid residue and 5 to 50 mol% has 10 carbon atoms. The polyester as the aliphatic dicarboxylic acid residue and the olefin-based polymer consist of 70:30 to 100: 0 (% by weight), and the polyester-based film (B) contains polyethylene terephthalate and polybutylene terephthalate at 60%. : 40 to 30: 70 (% by weight) of polyester, and the polyester films (A) and (B) have a heat shrinkage in the longitudinal direction at 150 ° C. of 4 to 30%. This is achieved by a method for producing a polyester-based film-coated metal plate, which is a feature of the invention.
[0010]
In this case, it is preferable that both ends of the resin film (A) and the olefin polymer of the layer (II) and the olefin polymer of both ends of the resin film (B) are the same.
[0011]
In this case, it is preferable that the olefin-based polymer is polyethylene and / or an ethylene-based copolymer.
[0012]
Further, in this case, it is preferable that the polyester (I) layer of the resin film (A) and the polyester of the resin film (B) have the same ratio of polyethylene terephthalate and polybutylene terephthalate.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
In the layer (I) of the polyester film (A) and the polyester film (B) in the present invention, dicarboxylic acid components other than terephthalic acid and ethylene glycol and butanediol other than terephthalic acid are used as long as the properties of polyethylene terephthalate and polybutylene terephthalate are not impaired. A glycol component can be used. For example, as dicarboxylic acids, aromatic dicarboxylic acids such as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, diphenylsulfonedicarboxylic acid, 5-sodium sulfoisophthalic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, decanedicarboxylic acid, Aliphatic dicarboxylic acids such as maleic acid, fumaric acid and dimer acid, oxycarboxylic acids such as p-oxybenzoic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid can be used. As glycol components other than ethylene glycol and butanediol, aliphatic glycols such as propanediol, pentanediol, hexanediol and neopentyl glycol, alicyclic glycols such as cyclohexanedimethanol, and aromatics such as bisphenol A and bisphenol S Glycol can be used.
[0014]
The polyester constituting the (II) layer of the polyester film (A) in the present invention is such that 50 mol% or more of the total acid component is a terephthalic acid residue and 5 to 50 mol% is an aliphatic dicarboxylic acid having 10 or more carbon atoms. It is necessary to be. If the terephthalic acid residue is less than 50 mol%, heat resistance is insufficient, and the releasability of the punch at the time of can making becomes poor, which is not preferable. Examples of the aliphatic dicarboxylic acid having 10 or more carbon atoms include sebacic acid, eicoic acid, decanedicarboxylic acid, and dimer acid. The dimer acid is obtained by a dimerization reaction of a higher unsaturated fatty acid such as oleic acid and generally has an unsaturated bond in the molecule, but one having a reduced degree of unsaturation by hydrogenation can also be used. Hydrogenation is more preferable because heat resistance and flexibility are improved. In the course of the dimerization reaction, a linear branched structure, an alicyclic structure and an aromatic ring structure are produced, but these structures and amounts are not particularly limited. An aliphatic dicarboxylic acid residue having less than 10 carbon atoms is not preferable because impact resistance is not sufficiently imparted. If the number of aliphatic dicarboxylic acid residues having 10 or more carbon atoms is less than 5 mol%, impact resistance is not sufficiently imparted, which is not preferable. Conversely, if it exceeds 50 mol%, the impact resistance is not only saturated, but also the heat resistance is lowered, which is not preferable. If the polyester constituting the layer (II) of the polyester film (A) has a terephthalic acid residue and an aliphatic dicarboxylic acid residue having 10 or more carbon atoms satisfying the above ranges, the polyester other than these acids may be used. The inclusion of a dicarboxylic acid residue is not particularly limited. The aliphatic dicarboxylic acid residue having 10 or more carbon atoms may be used alone or in combination of two or more. Further, the glycol residue of the polyester constituting the layer (II) of the polyester film (A) is not particularly limited, and fatty acids such as ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, and neopentyl glycol can be used. It may be a residue of an alicyclic glycol such as an aromatic glycol or cyclohexanedimethanol, or an aromatic glycol such as bisphenol A or bisphenol S.
[0015]
The polyester of the present invention may contain, if necessary, an antioxidant, a heat stabilizer, an ultraviolet absorber, a plasticizer, a pigment, an antistatic agent, a lubricant, a nucleating agent, a lubricant comprising inorganic or organic particles, and the like. May be.
[0016]
The method for producing the polyester in the present invention is not particularly limited. That is, those produced by either the transesterification method or the direct polymerization method can be used. Further, those produced by a solid-phase polymerization method for increasing the molecular weight may be used. In addition, use a polyester with a low oligomer content produced by a vacuum solid-phase polymerization method in order to reduce the amount of oligomers from the polyester resin in the past lamination process, retort process, etc. performed after filling the contents in the can. Is preferred. However, it is preferable that the polyester (I) of the resin film (A) and the polyester of the resin film (B) have the same ratio of polyethylene terephthalate and polybutylene terephthalate. The reason for this is that the resin films (A) and (B) obtained by subjecting the resin (A) and (B) extruded in layers to cooling unidirectional stretching and heat fixing after cooling and solidifying from the viewpoint of reducing waste of the resin. This is because the quality of the polyester film (A) coated on the metal plate becomes stable when the resin obtained by cutting and removing both ends is reused in the (II) layer of the resin film (A).
The melting point of the polyester used in the present invention is 180 ° C. or more, and the can-making property is assured (in the drawing / ironing process, the polyester film on the inner surface of the can is released from the punch, and the polyester film on the outer surface of the can is secured). This is necessary for suppressing galling (vertical scratches on the polyester film)).
[0017]
In the present invention, the olefin polymer used at both ends of the resin film (A), the (II) layer and both ends of the resin film (B) is preferably polyethylene and / or an ethylene copolymer. Low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ultra high molecular weight polyethylene, ethylene-propylene copolymer, ethylene butene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer , Ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer, ionomer, ethylene-anhydride A maleic acid graft copolymer, an ethylene-vinyl alcohol copolymer, or the like can be used. It is preferable that the olefin-based polymer used in both ends of the resin film (A) and the (II) layer and the olefin-based polymer used in both ends of the resin film (B) are the same. The reason for this is that the resin films (A) and (B) obtained by subjecting the resin (A) and (B) extruded in layers to cooling unidirectional stretching and heat fixing after cooling and solidifying from the viewpoint of reducing waste of the resin. This is because the quality of the polyester film (A) coated on the metal plate becomes stable when the resin obtained by cutting and removing both ends is reused in the (II) layer of the resin film (A).
[0018]
In the present invention, the ratio of the polyester to the olefin polymer in the polyester film needs to be 70:30 to 100: 0 (% by weight). If the olefin-based polymer exceeds 30% by weight, the can-making properties (punch release properties) are poor, which is not preferable.
[0019]
In the present invention, when the polyester and the olefin-based polymer are extruded in a layer form from a T-die, it is preferable to use the olefin-based polymer at both ends (a portion of one side of which is 5 cm or less).
In the present invention, a polymer obtained by dry blending or melt-mixing a polyester and an olefin-based polymer is melted in a known single-screw or twin-screw extruder, and then layered using a known multi-manifold die such as an edge lamination type. Is obtained.
[0020]
In the present invention, as the cooling and solidifying method, a known method of contacting the molten resin in a layer form from a T-die with a rotated cooling roll can be used. When the molten resin is brought into contact with the cooling roll, it is preferable to employ a method of forcibly blowing air or a method of bringing the resin into close contact with static electricity. In both the forced air spraying method and the electrostatic adhesion method, a method in which both ends and the central portion of the layered resin are performed independently is more preferable. Further, when the molten resin comes into contact with the cooling roll, it is more preferable to use a measure (for example, a device such as a vacuum chamber or a vacuum box) for reducing the entrained flow by reducing the pressure on the opposite side.
[0021]
In the present invention, the resin films (A) and (B) obtained by cutting and removing both ends as necessary after cooling and solidifying are cooled to 1.3 ° C. at a temperature equal to or higher than the glass transition point of the polyester and lower than the cold crystallization temperature. A longitudinal stretching of up to 6.0 times is performed, and then a heat treatment is performed under tension at a temperature of 50 ° C. or more and a melting point of the polyester of −20 ° C. for 1 to 20 seconds, and then both ends of the resin film are cut off to obtain a polyester film. (A) and (B) are obtained.
[0022]
The polyester films (A) and (B) used in the present invention must have a heat shrinkage in the longitudinal direction at 150 ° C. of 4 to 30%. If the heat shrinkage is less than 4%, the adhesion after lamination is undesirably reduced. Conversely, when the heat shrinkage exceeds 30%, wrinkles and blocking occur due to longitudinal shrinkage during storage until lamination, and wrinkles and bubbles are easily generated on the polyester film-coated metal plate, which is not preferable. .
[0023]
In the present invention, it is possible to reuse the raw material obtained by shredding both ends of the cut and removed resin film and then compacting or heating and melting the resin film in the (II) layer of the resin film (A). is there. The reuse rate is not particularly limited, but is preferably 5 to 90% by weight.
[0024]
In the present invention, as the metal plate, a surface-treated steel plate such as tin-free steel, an aluminum plate or an aluminum alloy plate, or an aluminum plate or an aluminum alloy plate subjected to a surface treatment can be used. After heating these metal plates to a melting point of polyester of −20 ° C. or more and a melting point of + 150 ° C., the polyester films (A) and (B) are laminated on the metal plates using a laminating roll. Is heated at the melting point of the polyester + 10 ° C. or higher and the melting point + 60 ° C., and then cooled with water and / or air to obtain a polyester film-coated metal plate. However, when laminating the polyester-based film (A) on a metal plate, it is preferable to contact the (II) layer side with the metal plate in order to ensure can-making properties.
[0025]
【Example】
Hereinafter, the present invention will be described based on examples.
[Evaluation method]
(1) Melting point of polyester The polyester composition was heated and melted at 300 ° C. for 5 minutes, and then quenched with liquid nitrogen to obtain 10 mg of a sample, which was heated to 10 ° C. in a nitrogen stream using a differential scanning calorimeter (DSC). The peak temperature of the endothermic peak accompanying melting when the exothermic / endothermic curve (DSC curve) was measured at a heating rate of / min was defined as the melting point Tm (° C.).
[0026]
(2) Neck-in Amount The average value (Acm) of the discharge port width of the T-die (60 cm) and the resin film width after cooling and solidification (resin film width before cutting off both ends) measured at n = 3 is used. The neck-in amount (cm) was determined by the following equation. A neck-in amount of 5 cm or less was evaluated as practical.
Neck-in amount (cm) = 60-A
[0027]
(3) Appearance of roll film after storage and cut resistance After storing the roll-shaped film at 40 ° C. and a relative humidity of 80% for one month, the appearance of the film and a tensile test according to JIS K 7127 (longitudinal direction) n = 30, No. 1 test piece of 15 mm width, test speed: 200 mm / min). The evaluation criteria were set as follows, and ○ was evaluated as practical.
[appearance]
○: No wrinkle, blocking, and thinning ×: With wrinkle, blocking, and thinning [cutting resistance]
Evaluated by the number of samples having a breaking elongation of <5%. (2/30 or less were evaluated as practical.)
[0028]
(4) Heat shrinkage rate Evaluated according to JIS Z 1715.
[0029]
(5) Method for producing a polyester-based film-coated metal plate On one side of an aluminum alloy plate (thickness: 0.26 mm, 3004-based alloy plate) heated to 250 ° C., a (II) layer of the polyester-based film (A) is formed as a metal plate. A polyester film (B) was simultaneously laminated on the other surface so as to make contact, and then heated at 275 ° C. and then rapidly cooled in water to produce a coated aluminum plate.
[0030]
(6) Releasability of the resin on the inner surface of the can and the processed punch The can was made at n = 10 so that the polyester film (A) of the coated aluminum plate was on the inner surface of the can, and the degree of buckling occurring at the upper part of the molded can was visually observed. Observed. The evaluation criteria were set as follows, and ○ was evaluated as practical.
：: No buckling occurred at the can opening. 座: Buckling occurred at about 1/3 of the circumference of the can opening. X: Buckling occurred at 1/3 or more of the circumference of the can opening.
(7) Galling resistance of the outer surface of the can (vertical scratches on the polyester film on the outer surface of the can)
The can was made at n = 10 so that the polyester film (A) of the coated aluminum plate was on the inner surface side of the can, and the degree of scratching of the outer polyester film (B) of the molded can body wall was visually observed. The evaluation criteria were set as follows, and ○ was evaluated as practical.
：: no scratches Δ: scratches occurred on about 1/3 of the outer surface ×: severe scratches occurred on 1/3 or more of the outer surface
(8) Impact Resistance A can of 7 cm square was cut out from the center of the body wall of a can obtained by heating an aluminum plate at 280 ° C. for 40 seconds and then rapidly cooling in water. A weight (600 g) having a tip diameter of 10 mm is dropped from a height of 10 cm on a surface corresponding to the outer surface of the can of this sample to give an impact. Then, the sample was placed on a glass container filled with 7% diluted hydrochloric acid (placed in a state where the convex portion of the sample was immersed), and after 3 days, the corrosion state of the convex portion was visually observed. The evaluation criteria were set as follows, and ○ was evaluated as practical.
：: no corrosion of the convex portion occurred x: corrosion of the convex portion occurred
(9) A sample obtained by heating a can at a temperature of 270 ° C. for 40 seconds and then quenching in water is used as a sample. After this sample was immersed in warm water at 80 ° C. for 10 minutes, the outer surface of the can obtained by rapid cooling in water was visually observed. The evaluation criteria were set as follows, and ○ was evaluated as practical.
：: Whitening is not conspicuous. 明 ら か に: Whitening is apparent, but the color of the aluminum alloy plate is visible. X: Color of the aluminum alloy plate is not visible due to whitening.
[Abbreviations and contents of polyester and olefin-based polymers used in Examples and Comparative Examples]
(1) PET: polyethylene terephthalate (2) PBT: polybutylene terephthalate (3) Polyester A: copolymer polyester of terephthalic acid / dimer acid having 36 carbon atoms (molar ratio 90/10) and ethylene glycol (4) polyester B Terephthalic acid / copolymerized polyester of dimer acid having 36 carbon atoms (molar ratio: 95/5) and ethylene glycol / 1,4-butanediol (molar ratio: 30/70) Polyester C: terephthalic acid and ethylene glycol / Copolymerized polyester with cyclohexanedimethanol (molar ratio 70/30) (6) Olefin A: Low-density polyethylene (Sumikasen G401, trade name, manufactured by Sumitomo Chemical Co., Ltd.)
(7) Olefin B: ethylene butene copolymer (manufactured by Mitsui Chemicals, Tuffmer A4085: trade name)
(8) Olefin C: ionomer (Himilan 1706: trade name, manufactured by Du Pont-Mitsui Polychemicals)
(9) Olefin D: ethylene-methyl acrylate copolymer (EMAC SP2205: trade name, manufactured by Eastman Chemical Company)
(10) Olefin F: polypropylene (Noblen FS2011DG2: trade name, manufactured by Sumitomo Chemical Co., Ltd.)
[0035]
[Example 1]
Polyester of PET / PBT = 40/60 (% by weight) as the (I) layer raw material of the resin film (A) and polyester A alone as the (II) layer raw material are melted at 270 ° C., and both ends of the resin film (A) The olefin A alone is melted at 250 ° C. as a raw material of the material, and then an edge lamination type T die (discharge port width at both ends / discharge port width at the center / discharge port width at both ends = 2 cm / 56 cm / 2 cm, 260 ° C.) (Heating), cast into a layered cooling roll (peripheral speed 20 m / min) (distance from T-die to ground contact point of molten resin on cooling roll 15 cm, center and both ends forced by separate devices) The resin film (A) was obtained by blowing air.
The resin film (A) was longitudinally stretched 3.0 times at a preheating temperature of 65 ° C. and a stretching temperature of 100 ° C., and was heat-treated at 150 ° C. for 3 seconds using a clip gripping setter, and then cut off at both ends (5 cm on one side). Then, a roll-shaped polyester film (A) having a thickness of 100 m and a thickness of 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness 12.5 μm) was obtained.
[0036]
Further, a polyester of PET / PBT = 40/60 (% by weight) is melted at 270 ° C. as a raw material at the center of the resin film (B), and olefin A alone is heated at 250 ° C. as a raw material at both ends of the resin film (B). And cooled in layers using an edge lamination type T die (discharge port width at both ends / discharge port width at center / discharge port width at both ends = 2 cm / 56 cm / 2 cm, heated to 260 ° C.) Cast into a roll (peripheral speed: 20 m / min) (distance from the T-die to the contact point of the molten resin with the cooling roll: 15 cm, forced air is blown at the center and both ends by separate devices) and the resin film (B) was obtained.
The resin film (B) was longitudinally stretched 3.0 times at a preheating temperature of 65 ° C. and a stretching temperature of 100 ° C., and was heat-treated at 150 ° C. for 3 seconds using a clip gripping setter. To give a roll-shaped polyester film (B) having a thickness of 16 μm and a length of 100 m.
[0037]
The roll-shaped polyester films (A) and (B) were stored at 40 ° C. for one month under the condition of a relative humidity of 80%, and then the both sides of a 3004 series aluminum alloy plate (0.26 mm thick) heated to 250 ° C. After the film was pressed and heated to 275 ° C., it was rapidly cooled in water to obtain a coated aluminum plate.
[0038]
After applying a forming lubricant to the coated aluminum plate thus obtained, it was heated and drawn at a plate temperature of 70 ° C. so that the polyester film (A) was on the inner surface side. Next, the temperature of the obtained cup was set to 40 ° C., and ironing was performed at a mold temperature of 80 ° C. to obtain a 350 ml-sized seamless can.
[0039]
Melting point of polyester, neck-in amount during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of inner can film and punch and degree of scratch on can outer film), Table 1 shows the impact resistance and the degree of whitening of the outer surface of the can after hot water treatment. The method of this example has a small neck-in amount, is excellent in economic efficiency, and has good laminating properties because there is no deterioration in appearance and cut resistance of the polyester film after storage, and is excellent in can-making properties. It can be said that this is a method for producing a polyester film-coated metal plate that can provide a metal can having excellent impact resistance and hot water whitening resistance on the outer surface.
[0040]
[Example 2]
The thickness was 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness 12.5 μm) and length was the same as in Example 1 except that polyester B was used as the raw material for the (II) layer of the resin film A. A roll-shaped polyester film (A) having a length of 100 m and a roll-shaped polyester film (B) having a thickness of 16 μm and a length of 100 m were obtained.
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0041]
Melting point of polyester, neck-in amount during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of inner can film and punch and degree of scratch on can outer film), Table 1 shows the impact resistance and the degree of whitening of the outer surface of the can after hot water treatment. The method of this example has a small neck-in amount, is excellent in economic efficiency, and has good laminating properties because there is no deterioration in appearance and cut resistance of the polyester film after storage, and is excellent in can-making properties. It can be said that this is a method for producing a polyester film-coated metal plate that can provide a metal can having excellent impact resistance and hot water whitening resistance on the outer surface.
[0042]
[Example 3]
The thickness was 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness) in the same manner as in Example 1 except that 87% by weight of polyester A and 13% by weight of olefin A were used as raw materials for layer (II) of resin film A. A roll-shaped polyester film (A) having a length of 12.5 μm) and a length of 100 m and a roll-shaped polyester film (B) having a thickness of 16 μm and a length of 100 m were obtained.
[0043]
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0044]
Melting point of polyester, neck-in amount during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of inner can film and punch and degree of scratch on can outer film), Table 1 shows the impact resistance and the degree of whitening of the outer surface of the can after hot water treatment. The method of this example has a small neck-in amount, is excellent in economic efficiency, and has good laminating properties because there is no deterioration in appearance and cut resistance of the polyester film after storage, and is excellent in can-making properties. It can be said that this is a method for producing a polyester film-coated metal plate that can provide a metal can having excellent impact resistance and hot water whitening resistance on the outer surface.
[0045]
[Example 4]
The same procedure as in Example 1 was repeated except that the raw material of the layer (II) of the resin film A was 87% by weight of polyester A and 13% by weight of olefin B, and the raw materials at both ends of the resin films (A) and (B) were olefin B. Roll-type polyester film (A) having a thickness of 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness 12.5 μm) and a length of 100 m, and a roll-type polyester film having a thickness of 16 μm and a length of 100 m A system film (B) was obtained.
[0046]
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0047]
Melting point of polyester, neck-in amount during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of inner can film and punch and degree of scratch on can outer film), Table 1 shows the impact resistance and the degree of whitening of the outer surface of the can after hot water treatment. The method of this example has a small neck-in amount, is excellent in economic efficiency, and has good laminating properties because there is no deterioration in appearance and cut resistance of the polyester film after storage, and is excellent in can-making properties. It can be said that this is a method for producing a polyester film-coated metal plate that can provide a metal can having excellent impact resistance and hot water whitening resistance on the outer surface.
[0048]
[Example 5]
The same procedure as in Example 1 was repeated except that the raw material of the layer (II) of the resin film A was 87% by weight of polyester A and 13% by weight of olefin C, and the raw materials at both ends of the resin films (A) and (B) were olefin C. Roll-type polyester film (A) having a thickness of 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness 12.5 μm) and a length of 100 m, and a roll-type polyester film having a thickness of 16 μm and a length of 100 m A system film (B) was obtained.
[0049]
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0050]
Melting point of polyester, neck-in amount during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of inner can film and punch and degree of scratch on can outer film), Table 1 shows the impact resistance and the degree of whitening of the outer surface of the can after hot water treatment. The method of this example has a small neck-in amount, is excellent in economic efficiency, and has good laminating properties because there is no deterioration in appearance and cut resistance of the polyester film after storage, and is excellent in can-making properties. It can be said that this is a method for producing a polyester film-coated metal plate that can provide a metal can having excellent impact resistance and hot water whitening resistance on the outer surface.
[0051]
[Example 6]
The raw material of the (II) layer of the resin film A was made of 87% by weight of polyester A and 13% by weight of olefin composed of olefin A / olefin D = 70/30 (% by weight), and both ends of the resin films (A) and (B) were formed. Except that the raw material was olefin A / olefin D = 70/30 (% by weight), the thickness was 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness 12.5 μm) and long as in Example 1. A roll-shaped polyester film (A) having a length of 100 m and a roll-shaped polyester film (B) having a thickness of 16 μm and a length of 100 m were obtained.
[0052]
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0053]
Melting point of polyester, neck-in amount during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of inner can film and punch and degree of scratch on can outer film), Table 1 shows the impact resistance and the degree of whitening of the outer surface of the can after hot water treatment. The method of this example has a small neck-in amount, is excellent in economic efficiency, and has good laminating properties because there is no deterioration in appearance and cut resistance of the polyester film after storage, and is excellent in can-making properties. It can be said that this is a method for producing a polyester film-coated metal plate that can provide a metal can having excellent impact resistance and hot water whitening resistance on the outer surface.
[0054]
[Example 7]
The raw material of the (II) layer of the resin film A was composed of 85% by weight of polyester A and both ends (85% by weight of olefin A) cut and removed before obtaining the polyester films (A) and (B) in Example 1. Except that the polymer obtained by granulation was 15% by weight, the thickness was 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness 12.5 μm) and length was 100 m in the same manner as in Example 1. A roll-shaped polyester film (A) and a roll-shaped polyester film (B) having a thickness of 16 μm and a length of 100 m were obtained.
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0055]
Melting point of polyester, neck-in amount during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of inner can film and punch and degree of scratch on can outer film), Table 1 shows the impact resistance and the degree of whitening of the outer surface of the can after hot water treatment. The method of this example has a small neck-in amount, is excellent in economic efficiency, and has good laminating properties because there is no deterioration in appearance and cut resistance of the polyester film after storage, and is excellent in can-making properties. It can be said that this is a method for producing a polyester film-coated metal plate that can provide a metal can having excellent impact resistance and hot water whitening resistance on the outer surface.
[0056]
[Comparative Example 1]
An attempt was made to obtain a roll-shaped resin film in the same manner as in Example 1 except that the raw materials at both ends of the resin film (A) and the resin film (B) were made of PET / PBT = 40/60 (wt%) polyester. However, unless the neck-in amount is large and both ends are cut and removed by 18 cm, a central portion having a uniform thickness distribution cannot be obtained, so this method is not preferable as a method for producing a polyester film-coated metal sheet. Table 2 shows the melting point of polyester and the amount of neck-in during casting.
[0057]
[Comparative Example 2]
The raw material of the layer (I) of the resin film (A) is polyester of PET / PBT = 20/80 (% by weight), and the raw material of the central part of the resin film (B) is PET / PBT = 20/80 (% by weight). An attempt was made to form a film in the same manner as in Example 1 except that the polyester was used. However, the resin film often cracked between the cooling roll and the longitudinally extending preheating roll, and more often the resin film was broken during longitudinal stretching. This method is not preferable as a method for producing a polyester film, since roll-type polyester films (A) and (B) cannot be obtained. Table 2 shows the melting point of polyester and the amount of neck-in during casting.
[0058]
[Comparative Example 3]
The raw material of the (I) layer of the resin film (A) is polyester of PET / PBT = 70/30 (% by weight), and the raw material of the central part of the resin film (B) is PET / PBT = 70/30 (% by weight). A roll-shaped polyester film (A) having a thickness of 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness 12.5 μm) and a length of 100 m was prepared in the same manner as in Example 1 except that the polyester was used. A roll-shaped polyester film (B) having a thickness of 16 μm and a length of 100 m was obtained.
[0059]
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0060]
Melting point of polyester, neck-in amount during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of inner can film and punch and degree of scratch on can outer film), Table 2 shows the impact resistance and the degree of whitening of the outer surface of the can after the hot water treatment. This method has a small neck-in amount, is excellent in economical efficiency, has good laminating properties because there is no deterioration in appearance and cut resistance of the polyester film after storage, has excellent can-making properties, and has a metal can. Was excellent in impact resistance, but was inferior in hot water whitening resistance on the outer surface, which was not preferable as a method for producing a polyester film-coated metal sheet.
[0061]
[Comparative Example 4]
The thickness of the resin film (A) was 25 μm (the thickness of the (I) layer was 12.5 μm, and the thickness of the (II) layer was the same as in Example 1 except that the raw material of the (I) layer and the (II) layer was changed to Polysil A). A roll-shaped polyester film (A) having a layer thickness of 12.5 μm) and a length of 100 m and a roll-shaped polyester film (B) having a thickness of 16 μm and a length of 100 m were obtained.
[0062]
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0063]
Table 2 shows the melting point of the polyester, the neck-in amount at the time of casting, and the can-making properties (the releasability between the resin film on the inner surface of the can and the punch and the degree of scratching on the resin film on the outer surface of the can). This method has a small neck-in amount, is excellent in economical efficiency, and has good laminating properties because there is no poor appearance of the polyester film after storage and no decrease in cut resistance, but when a coated aluminum plate is made, Since the inner surface of the can and the processed punch adhere to each other and buckling occurs over the entire periphery of the opening of the can, the can-making property is inferior, which is not preferable as a method for producing a polyester film-coated metal sheet.
[0064]
[Comparative Example 5]
The same procedure as in Example 1 was repeated except that the raw material of the (I) layer of the resin film (A) and the central part of the resin film (B) were polyester C alone, and the thickness was 25 μm ((I) layer thickness 12.5 μm, ( II) A roll-shaped polyester film (A) having a layer thickness of 12.5 μm) and a length of 100 m and a roll-shaped polyester film (B) having a thickness of 16 μm and a length of 100 m were obtained.
[0065]
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0066]
Melting point of polyester, amount of neck-in during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of can inner film and punch and degree of scratch on outer film of can) It is shown in Table 2. This method has a small neck-in amount, is excellent in economic efficiency, and there is no appearance defect of the polyester film after storage, but the cut resistance is lowered, and when the coated aluminum plate is made into a can, the can inner film and The processing punch adheres and buckling occurs over the entire circumference of the can opening, and furthermore, the entire circumference of the can outer surface film is scratched, resulting in poor can-making properties, which is not preferable as a method for producing a polyester film-coated metal plate. .
[0067]
[Comparative Example 6]
The thickness of the resin film (A) was 25 μm ((P) as in Example 1 except that the raw material of the (II) layer was PET / PBT = 40/60 (wt%) of polyester 50 wt% and olefin 50 wt%. (I) layer thickness of 12.5 μm, (II) layer thickness of 12.5 μm) and a roll-shaped polyester film (A) having a length of 100 m and a roll-shaped polyester film having a thickness of 16 μm and a length of 100 m (B). Obtained.
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0068]
Melting point of polyester, amount of neck-in during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of can inner film and punch and degree of scratch on outer film of can) It is shown in Table 2. This method has a small neck-in amount, is excellent in economical efficiency, and has good laminating properties because there is no poor appearance of the polyester film after storage and no decrease in cut resistance, but when a coated aluminum plate is made, In addition, the punch was difficult to remove, and buckling occurred in about 1/3 of the opening on the inner surface of the can, resulting in poor can-manufacturability, which is not preferable as a method for producing a polyester film-coated metal plate.
[0069]
[Comparative Example 7]
Two kinds of polyester-based unstretched films (100 m roll-shaped film) having a thickness of 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness 12.5 μm) and 16 μm were obtained from the raw materials of Example 1.
Table 2 shows the melting point of the polyester, the neck-in amount at the time of casting, the appearance, cut resistance, and heat shrinkage of the roll film after storage.
As a result of storage in the same manner as in Example 1, the cut resistance of the film was poor, wrinkles and blocking occurred, and a coated aluminum plate having a good appearance could not be obtained. Not preferred.
[0070]
[Comparative Example 8]
Except for setting the heat treatment temperature after the longitudinal stretching at 190 ° C., the same as in Example 1 was carried out in a roll shape having a thickness of 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness 12.5 μm) and length 100 m. A polyester film (A) and a roll-shaped polyester film (B) having a thickness of 16 μm and a length of 100 m were obtained.
[0071]
Next, a coated aluminum plate was prepared and made in the same manner as in Example 1, to obtain a 350 ml-sized seamless can.
[0072]
Melting point of polyester, amount of neck-in during casting, appearance and cut resistance of roll film after storage, heat shrinkage, can-making properties (releasability of can inner film and punch and degree of scratch on outer film of can) It is shown in Table 2. This method has a small amount of neck-in and is excellent in economical efficiency, and there was no poor appearance of the polyester film after storage and no decrease in cut resistance.However, when the coated aluminum plate was canned, the film was peeled off. It is not preferable as a method for producing a system-film-coated metal plate.
[0073]
[Comparative Example 9]
Roll-like polyester having a thickness of 25 μm ((I) layer thickness 12.5 μm, (II) layer thickness 12.5 μm) and a length of 100 m in the same manner as in Example 1 except that the heat treatment was not performed after the longitudinal stretching. A film (A) and a roll-shaped polyester film (B) having a thickness of 16 μm and a length of 100 m were obtained.
Table 2 shows the melting point of the polyester, the neck-in amount at the time of casting, the appearance, cut resistance, and heat shrinkage of the roll film after storage.
This method has a small amount of neck-in and is economical, and there is no decrease in the cut resistance of the polyester film after storage. Is not preferable as a method for producing a polyester film-coated metal plate, since a coated aluminum plate having a good quality cannot be obtained.
[0074]
[Comparative Example 10]
The same procedure as in Example 1 was repeated except that the raw material of the (II) layer of the resin film A was 87% by weight of polyester A and 13% by weight of olefin F, and the raw materials at both ends of the resin films (A) and (B) were olefin F. However, this method is not preferable as a method for producing a metal film coated with a polyester film because of a large neck-in amount. Table 2 shows the melting point of polyester and the amount of neck-in during casting.
[0075]
[Table 1]

[0076]
[Table 2]

[0077]
【The invention's effect】
The method for producing a polyester-based film-coated metal sheet of the present invention is not only an economical production method for eliminating waste of raw materials, but also a production method capable of obtaining a polyester-based film-coated metal sheet having excellent flavor properties. is there. Furthermore, it has excellent can-making properties (especially, the releasability of the resin film on the inner surface of the can and the processing punch and the scratch resistance of the resin film on the outer surface of the can). An extremely useful polyester because it is unlikely to have poor appearance (whitening of the resin film) and it is unlikely that the impact resistance will decrease even if heating is performed assuming baking on the exterior surface for the purpose of beautification after can-making. It can be said to be a method for producing a system film-coated metal plate.

Claims (4)

In a production method, one side of a metal plate is coated with a film (A) mainly composed of crystalline polyester having a melting point of 180 ° C. or higher, and the other side is coated with a film (B) composed of crystalline polyester having a melting point of 180 ° C. or higher. Using a T-die, the resin films (A) and (B) obtained by cooling and solidifying the molten resin film extruded into a layer in a state where the olefin-based polymer is merged at both ends are uniaxially stretched in the longitudinal direction. A method for obtaining polyester films (A) and (B) by heat-setting and then cutting off both ends, and laminating the polyester films (A) and (B) to a metal plate heated in another step. The polyester film (A) has a composite structure of (I) layer / (II) layer, and the (I) layer is polyethylene. The phthalate and the polybutylene phthalate are composed of 60:40 to 30:70 (% by weight), and the (II) layer has 50% by mole or more of terephthalic acid residues and 5 to 50% by mole of 10 or more carbon atoms in the total acid component. The polyester which is an aliphatic dicarboxylic acid residue and the olefin-based polymer are composed of 70:30 to 100: 0 (% by weight), and the polyester-based film (B) is composed of polyethylene terephthalate and polybutylene terephthalate in a ratio of 60:40. ~ 30: 70 (wt%) polyester, and the polyester films (A) and (B) have a heat shrinkage in the longitudinal direction at 150 ° C of 4 to 30%. For producing a polyester film-coated metal sheet to be formed. The method for producing a polyester-based film-coated metal sheet according to claim 1, wherein both ends of the resin film (A), the olefin-based polymer of the layer (II) and the olefin-based polymers at both ends of the resin film (B). A method for producing a polyester film-coated metal sheet, wherein the polymers are the same. The method for producing a polyester-based film-coated metal sheet according to claim 1, wherein the olefin-based polymer is polyethylene and / or an ethylene-based copolymer. . The method for producing a polyester film-coated metal sheet according to claim 1, wherein the polyester (I) of the resin film (A) and the polyester of the resin film (B) have the same ratio of polyethylene terephthalate and polybutylene terephthalate. A method for producing a metal sheet coated with a polyester film, the method comprising: