JP3293297B2 - Polyester film for metal plate lamination - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester film for laminating a metal plate. More specifically, the present invention relates to a polyester film for laminating a metal plate which is excellent in adhesiveness, moldability, impact resistance and taste characteristics and is suitable for a metal can produced by molding.

[0002]

2. Description of the Related Art Conventionally, the inner and outer surfaces of a metal can are coated with various thermosetting resins, such as epoxy and phenol, dissolved or dispersed in a solvent to prevent corrosion. Has been widely practiced. However, such a method of coating the thermosetting resin requires a long time for drying the paint, and has unfavorable problems such as a decrease in productivity and environmental pollution due to a large amount of an organic solvent.

[0003] As a method of solving these problems, a polyester film is laminated on a steel plate, an aluminum plate, or a metal plate which has been subjected to various surface treatments such as plating, which is a material for a metal can. When a metal can is manufactured by drawing or ironing a plate, the polyester film is required to have the following characteristics.

(1) The adhesiveness to a metal plate is excellent.

(2) It is excellent in moldability.

(3) The polyester film does not peel off, crack or pinhole due to impact on the metal can.

(4) The scent component of the contents of the can is not adsorbed on the polyester film or the odor of the polyester film does not impair the flavor of the contents (hereinafter referred to as taste characteristics).

Many proposals have been made to solve these requirements. For example, JP-A-64-22530 discloses a polyester film having a specific density and plane orientation coefficient, and JP-A-2-57339 discloses a polyester film having a specific density. Discloses a copolymerized polyester film having specific crystallinity. However, these proposals do not comprehensively satisfy the above-mentioned various required properties, and in particular, have a sufficiently satisfactory level of impact resistance and taste characteristics after heat history in the can making process. I couldn't say that.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and is excellent in adhesiveness, moldability, heat resistance, impact resistance and taste characteristics, especially after can-making. there impact resistance, to provide a suitable metal plate laminating copolymer polyester Ruff <br/> Irumu the metal can be produced by excellent molding taste characteristics.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide a polyester having a melting point of from 120 to 230.degree.
A layer as a component and a polyether having a melting point of 231 to 260 ° C.
A polyester film for laminating a metal plate, comprising laminating a layer B mainly comprising stell, containing 0.01 to 1% by weight of a diethylene glycol component and 0.001 to 1% by weight of an antioxidant. Can be achieved by:

The polyester in the present invention is a polymer comprising a dicarboxylic acid component and a glycol component. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfondicarboxylic acid, diphenoxy acid. Aromatic dicarboxylic acids such as ethanedicarboxylic acid, 5-sodium sulfoisophthalic acid and phthalic acid; aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid and fumaric acid; cyclohexyne dicarboxylic acid Examples thereof include alicyclic dicarboxylic acids such as acids, and oxycarboxylic acids such as p-oxybenzoic acid. Among these dicarboxylic acid components, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid are preferable from the viewpoint of impact resistance and taste characteristics. On the other hand, as the glycol component, for example, ethylene glycol, propanediol,
Examples thereof include aliphatic glycols such as butanediol, pentanediol, hexanediol, and neopentyl glycol; alicyclic glycols such as cyclohexanedimethanol; and aromatic glycols such as bisphenol A and bisphenol S. Among them, ethylene glycol is preferred among these glycol components from the viewpoint of impact resistance and taste characteristics. In addition, two or more of these dicarboxylic acid components and glycol components may be used in combination.

As long as the effects of the present invention are not impaired, a polyfunctional compound such as trimellitic acid, trimesic acid or trimethylolpropane may be copolymerized with the copolymerized polyester.

The polyester used in the present invention has a heat resistance of 120 to 260 ° C. as a melting point,
It is necessary in terms of sufficient adhesion to a metal plate. Preferably, polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, and copolymerized polyesters thereof, and the like.In addition, when these acid components or glycol components are copolymerized with these polyesters, all the acid components constituting the polyester are used. From the viewpoint of adhesiveness to the metal plate, it is preferable that the copolymerization with the metal plate is 1 to 40 mol% with respect to all glycol components, and more preferably 5 to 30 mol%, particularly preferably 8 to 20 mol%. If the copolymerization amount is less than 1 mol%, the adhesion to the metal plate is poor, and the film is peeled off or the impact resistance is poor, for example, the crystallization of the film is promoted in the production process of the metal can. On the other hand, if it exceeds 40 mol%, the melting point is low, and the impact resistance is poor. Preferred copolymerization components include isophthalic acid, butanediol, etc., with isophthalic acid being particularly preferred.

In the present invention, the diethylene glycol component is contained in an amount of 0.01 to 1% by weight in order to prevent a reduction in impact resistance due to heat history such as drying and printing baking in the can making process.
It is necessary to contain, preferably 0.01 to
0.8% by weight, more preferably 0.01 to 0.6% by weight, particularly preferably 0.01 to 0.5% by weight. If the content of diethylene glycol is less than 0.01 % by weight, the polymerization process becomes complicated and the cost is unfavorable. If it exceeds 1% by weight, the polyester deteriorates due to heat history in the can-making process, and the film has an impact resistance. Is greatly deteriorated, which is not preferable. Diethylene glycol is by-produced during the production of polyester. To reduce the amount to 1% by weight or less, a method of shortening the polymerization time or limiting the amount of an antimony compound, a germanium compound, etc. used as a polymerization catalyst, a liquid phase polymerization, And a method of combining solid phase polymerization and the method, but the method is not particularly limited.

Further, in the present invention, the impact resistance after receiving a thermal history of 200 ° C. or more and the impact resistance after receiving a treatment with pressurized steam at about 120 ° C. (retort treatment) are improved. Must contain 0.001 to 1% by weight of an antioxidant. 0.00 amount of antioxidant
If it is less than 1% by weight, there is no effect of improving impact resistance, and if it is more than 1% by weight, taste characteristics are lowered, which is not preferable.

The type of the antioxidant is not particularly limited, and known antioxidants classified into, for example, hindered phenols, hydrazines, and phosphites can be suitably used. Among them, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-)
Hydroxyphenyl) propionate], 3,5-di-
t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,
4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris (2,4-di-t-butylphenyl) phosphite and the like can be suitably used.

An A layer mainly composed of polyester having a melting point of 120 to 230 ° C .;
The laminated film obtained by laminating the layer B containing the polyester as a main component not only improves the adhesion between the layer A and the metal plate, but also retains the baking of the can after baking by the layer B. This is preferable because the tool does not damage the inner surface of the can.

From the viewpoint of taste characteristics, it is preferable that the layer B contains substantially no antioxidant, and only the layer A contains an antioxidant.

In the present invention, a film comprising a layer A mainly composed of polyester having a melting point of 100 to 230 ° C. and a layer B mainly composed of polyester having a melting point of 231 ° C. to 260 ° C. The composition, catalyst, amount of diethylene glycol, and amount of carboxyl terminal group in each layer may be different. When the edge of the film is collected, it is preferable that the film be collected in the layer A from the viewpoint of taste characteristics.

Further, the laminated film preferably has a ratio of the thickness of the layer A to the thickness of the layer B of 20: 1 to 1: 1 (A: B) in view of taste characteristics and impact resistance.
A ratio of 5: 1 to 4: 1 (A: B) is preferable from the viewpoint of impact resistance.

Preferably, the intrinsic viscosity [η] is 0.7.
As described above, it is more preferable that the intrinsic viscosity [η] is 0.75 or more, because impact resistance and taste characteristics can be further improved.

Further, in order to improve taste characteristics, the content of acetaldehyde in the polyester should be 50 ppm or less,
Preferably not more than 40 ppm, more preferably 30 pp
m, particularly preferably 20 ppm or less. When the content of acetaldehyde exceeds 50 ppm, the taste characteristics are inferior. The content of acetaldehyde in the film is 50 pm
Although the method to be described below is not particularly limited, for example, in order to remove acetaldehyde generated by thermal decomposition at the time of producing a polyester by a polycondensation reaction or the like, the polyester under reduced pressure or under an inert gas atmosphere, A method of performing heat treatment at a temperature of not more than the melting point, preferably a method of solid-phase polymerization of polyester at a temperature of not less than 150 ° C. under a reduced pressure or an inert gas atmosphere at a temperature of not more than the melting point, and a method of forming a melt film using a vented extruder When the polyester is melt extruded, the extrusion temperature is set to the melting point + 40 ° C.
Within, preferably within a melting point + 30 ° C., in a short time.

The polyester of the present invention preferably contains germanium element in an amount of 1 to 500 ppm, more preferably 5 to 300 ppm, particularly preferably 10 to 100 ppm from the viewpoint of taste characteristics. When the amount of germanium element is less than 1 ppm, the effect of improving taste characteristics is not sufficient,
If it exceeds 500 ppm, foreign matter is generated in the polyester, so that impact resistance is deteriorated and taste characteristics are deteriorated.
The polyester of the present invention can improve taste characteristics by including the above-mentioned specific amount of the germanium element in the polyester. The method for incorporating the germanium element into the polyester is not particularly limited, but it is usually preferable to add a germanium compound as a polymerization catalyst at any stage before the production of the polyester is completed. As such a method, for example, a method of directly adding a powder of a germanium compound, or as described in Japanese Patent Publication No. 54-22234, dissolves a germanium compound in a glycol component which is a starting material of a polyester. And the like. Examples of the germanium compound include germanium dioxide, germanium hydroxide containing crystal water, or germanium alkoxide compounds such as germanium tetramethoxide, germanium tetraethoxide, germanium tetrabutoxide, and germanium ethylene glycolide, germanium phenolate, and germanium β-.
Examples thereof include germanium phenoxide compounds such as naphtholate, phosphorus-containing germanium compounds such as germanium phosphate and germanium phosphite, and germanium acetate. Among them, germanium dioxide is preferable.

Further, it is preferable that the carboxyl terminal group of the polyester film of the present invention is 45 equivalents / ton or less in view of impact resistance and taste characteristics of the film. In particular, it is preferable to set the carboxyl terminal group to 40 equivalents / ton or less in terms of film recoverability and impact resistance.

The polyester of the present invention has an oligomer content of 0.8% by weight in view of taste characteristics.
It is preferably at most 0.7% by weight, more preferably at most 0.6% by weight. 0.8% by weight of oligomer in copolymerized polyester
If it exceeds, taste characteristics are inferior and it is not preferable. The method for reducing the content of the oligomer in the polyester to 0.8% by weight or less is not particularly limited, but a method similar to the above-described method for reducing the acetaldehyde content in the copolymerized polyester may be employed. Can be achieved.

For the production of the polyester of the present invention, any conventionally known method can be employed and is not particularly limited. For example, a case will be described in which an isophthalic acid component is copolymerized with polyethylene terephthalate and germanium dioxide is added as a germanium compound. The terephthalic acid component, isophthalic acid component and ethylene glycol are subjected to transesterification or esterification reaction, and then germanium dioxide is added.Then, the polycondensation reaction is continued under high temperature and reduced pressure until a constant diethylene glycol content is reached. Get. Then, the obtained polymer is subjected to a solid-phase polymerization reaction under reduced pressure or an inert gas atmosphere at a temperature not higher than its melting point to reduce the content of acetoadheride to obtain a predetermined intrinsic viscosity [η] and a carboxyl end group. And the like.

In producing the polyester of the present invention,
Conventionally known reaction catalysts and coloring inhibitors can be used. Examples of the reaction catalyst include alkali metal compounds, alkaline earth metal compounds, zinc compounds, lead compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, and titanium. Examples of the coloring inhibitor such as a compound include a phosphorus compound.

The copolyester of the present invention contains 0.001 to 8 μm of inorganic and / or organic particles having an average particle diameter of 0.001 to 8 μm in order to improve the handleability of the film and the moldability of the metal can. -10% by weight, more preferably 0.1 to 5% by weight.
0.005 μm of inorganic and / or organic particles
Preferably, it is contained at 3% by weight. Examples of the inorganic particles and / or organic particles include inorganic particles such as wet and dry silica, colloidal silica, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, mica, kaolin, and clay, and styrene, silicone, and acrylic acids. And the like. Among them, wet and dry colloidal silica, inorganic particles such as alumina and styrene, silicone, acrylic acid, methacrylic acid, polyester,
Organic particles containing divinylbenzene or the like as a constituent component can be exemplified. Two or more of these inorganic particles and / or organic particles may be used in combination.

Although the particles may be added to either the A layer or the B layer, it is preferable to add the particles to the B layer for handling. On the other hand, particles may be added to the layer A as long as the properties are not impaired in terms of recovery or the like. When particles are not contained, when the polymer is melt-extruded and solidified with a casting drum, a method is adopted in which the layer B is turned into a drum surface on a roughened drum, the film is pressed with air, and the film is rapidly cooled and solidified. May be.

Further, in producing the polyester film of the present invention, additives such as a plasticizer, an antistatic agent, a weathering agent, a terminal blocking agent and the like can be used as needed.

The film made of the copolymerized polyester in the present invention may be an unstretched sheet-like film, or a uniaxially or biaxially stretched film. In a molding method in which film formability is regarded as important, such as ironing, an unstretched sheet or a plane orientation coefficient fn obtained from refractive indexes (Nx, Ny, Nz) in a longitudinal direction, a width direction, and a thickness direction is used. = (Nx + Ny) / 2-Nz
Is preferably a stretched film having a value of 0 to 0.12, and an unstretched film is particularly preferred from the viewpoint of moldability.

The thickness of the polyester film of the present invention is not particularly limited, but is preferably 5 to 50 μm, more preferably 8 to 40 μm, particularly preferably 8 to 40 μm, in consideration of the moldability, impact resistance and taste characteristics of the metal can. 10-35 μm
It is.

The polyester film of the present invention can be formed by any conventionally known method. next,
The method for producing the film of the present invention will be described but is not limited thereto.

As polyester A, 17.5 mol% of isophthalic acid copolymerized polyethylene terephthalate containing 0.1% by weight of an antioxidant (germanium element content: 40 pp)
m, [η] = 0.85, diethylene glycol 0.92
Weight%, melting point 213 ° C, acetaldehyde amount 12pp
m, carboxyl end group 21 equivalents / ton), as polyester B, copolymerized polyethylene terephthalate of 5 mol% isophthalic acid (germanium element amount 42 ppm, [η]
= 0.90, diethylene glycol 0.89% by weight, melting point 240 ° C, acetaldehyde amount 10ppm, carboxyl end group 20 equivalents / ton) using a twin-screw vent type separate extruder (extruder temperature set to melting point + 25 ° C) And then melted, then laminated in two layers by a feed block, discharged from a normal die, cooled and solidified by a cooling drum to obtain a cast film. The two-layer laminated film thus obtained is subjected to heat aging or surface activation treatment as required, and then wound up.

Further, a method of biaxially stretching the above-mentioned polyester cast film simultaneously or sequentially may be performed. In the case of sequential biaxial stretching, stretching in the longitudinal direction or the width direction can be performed twice or more. The stretch ratio in the longitudinal direction and the width direction of the film can be arbitrarily set according to the degree of orientation, strength, elastic modulus and the like of the target film, but is preferably 2.5 to 5.0 times. Either the stretching ratio in the longitudinal direction or the stretching ratio in the width direction may be increased, and may be the same. The stretching temperature can be any temperature within the range of the glass transition temperature of the polyester or higher and the crystallization temperature or lower, but is usually 80 to 150.
C is preferred. Further, after biaxial stretching, heat treatment of the film can be performed. This heat treatment can be performed by any conventionally known method such as in an oven or on a heated roll. The heat treatment temperature can be any temperature from the crystallization temperature of the polyester to the softening point, but is preferably from 120 to 240 ° C. The heat treatment time can be arbitrarily set, but it is usually preferable to perform the heat treatment for 1 to 60 seconds. The heat treatment may be performed while relaxing the film in the longitudinal direction and / or the width direction.

The metal plate of the present invention is not particularly limited.
From the viewpoint of formability, a metal plate made of iron, aluminum, or the like is preferable. Further, in the case of a metal plate made of iron, an inorganic oxide coating layer on the surface thereof for improving adhesion and corrosion resistance, for example, chromic acid treatment, phosphoric acid treatment, chromic acid / phosphoric acid treatment, electrolytic chromic acid treatment A chemical conversion treatment coating layer represented by, for example, a chromate treatment or a chromium chromate treatment may be provided. In particular, in terms of chromium metal, 6.5 to chrome
A chromium hydrated oxide of 150 mg / m ² is preferable, and a spreadable metal plating layer such as nickel, tin, zinc, aluminum, gunmetal, brass, etc. may be provided. It is preferable that tin plating has a plating amount of 0.5 to 15 mg / m ² , and nickel or aluminum has a plating amount of 1.8 to 20 g / m ² .

The film for metal lamination of the present invention can be suitably used for coating the inner and outer surfaces of a two-piece metal can produced by drawing or ironing. In addition, good metal adhesion for covering the lid of a two-piece can, or the body, lid, and bottom of a three-piece can,
Since it has moldability, it can be preferably used. In particular, the colored film of the present invention can be used for coating the outer surface. For this reason, a coloring agent can be blended in the polyester layer. As the coloring agent, white, red and the like are preferably used, and titanium oxide, zinc white, lithophone,
5-50 colorants selected from inorganic or organic pigments, etc.
%, Preferably 15 to 40% by weight. If the addition amount is less than 5% by weight, the color tone, whiteness and the like are inferior and are not preferred. If necessary, a pinking agent, a bluing agent and the like may be used in combination.

[0038]

[Evaluation method of properties] The properties of the polyester film were measured and evaluated by the following methods.

(1) Content of diethylene glycol component in polyester Measured by NMR (13C-NMR spectrum).

(2) Content of Germanium Element in Polyester The content of the germanium element in the polyester composition and the peak intensity were quantified by X-ray fluorescence measurement.

(3) Intrinsic Viscosity of Polyester Polyester is dissolved in orthochlorophenol,
Measured in ° C.

(4) Melting Point of Polyester A polyester chip was crystallized and subjected to 10 ° C./C with a differential scanning calorimeter (DSC-2, manufactured by Perkin-Elmer).
The measurement was performed at a heating rate of min.

(5) Plane Orientation Coefficient Measured with an Abbe refractometer using sodium D line (wavelength 589 nm) as a light source. The plane orientation coefficient fn = (Nx + Ny) / 2-Nz obtained from the refractive indexes (Nx, Ny, Nz) in the longitudinal direction, the width direction, and the thickness direction was calculated and obtained.

(6) Impact resistance The adhesive surface of the polyester film and the tin-plated tin metal plate are laminated by heating and pressurizing to a temperature of 180 to 230 ° C., and an ironing machine [forming ratio (maximum thickness / minimum thickness)]
= 3.0], and bottom molding etc. are performed.
A ning can was obtained. After baking, baking at 220 ° C for 10 minutes, baking, retorting at 120 ° C x 30 minutes, filling with commercially available oolong tea, leaving at 20 ° C for 24 hours, and leaving from the outer surface of the can bottom After applying an impact to each of the five points with a punch, the contents were masked with a wax on the inner surface of the can except for the contents, and 1% saline was poured into the cup. A voltage of 6 V was applied to the electrodes and the metal can in the saline and the current was applied. The value was read.

Class A: less than 0.5 mA Class B: 0.5 mA or more and less than 1 mA Class C: 1 mA or more and 3 mA or less Class D: 3 mA or more

(7) Taste Characteristics The can (6) (diameter 6 cm, height 12 cm) was filled with a perfume aqueous solution (d-limonene 10 ppm aqueous solution) at 20 ° C. for 5 days, and the can was charged at 80 ° C. for 30 minutes with nitrogen. The components removed by heating in an air stream were quantified by gas chromatography to determine the amount of adsorbed d-limonene per 1 g of the film, and the taste characteristics of the film were evaluated.

In addition, a perfume aqueous solution (d-
Limonene (20 ppm aqueous solution) was added, left for one month after sealing, then opened, and the change in odor was evaluated by a sensory test according to the following criteria.

Grade A: no change in odor B class: slight change in odor C class: change in odor

[0049]

The present invention will be described in detail with reference to the following examples.

Example 1 Polyethylene terephthalate copolymerized with 17.5 mol% of isophthalic acid containing 0.1% by weight of an antioxidant IRGANOX1010 manufactured by Ciba Geigy KK as polyester A (germanium element amount: 40 ppm, [η] = 0.
85, 0.90% by weight of diethylene glycol, melting point 21
3 ° C., 8 ppm of acetaldehyde, 21 equivalents / ton of carboxyl terminal groups, 5 mol% of isophthalic acid copolymerized polyethylene terephthalate as polyester B (42 ppm of germanium element, 0.5 wt% of silicon oxide particles having an average particle diameter of 2 μm, [η] ] = 0.90, 0.89% by weight of diethylene glycol, melting point 240 ° C., acetaldehyde amount 6 ppm, carboxyl end group 20 equivalents / ton) and a twin-screw vent type extruder (extruder temperature: melting point +2)
(Set at 5 ° C, average residence time about 20 minutes)
Then, two layers (Polyester A)
Layer / polyester B layer = 9/1), discharged from a normal die, cooled and solidified by a cooling drum to obtain a 30 μm cast film. The obtained film was composed of 0.90% by weight of diethylene glycol and 12p of acetaldehyde.
pm, [η] = 0.78, and 0.6% by weight of the oligomer.

Table 1 shows the physical properties of the two-layer laminated cast film thus obtained. As you can see from the table,
Both impact resistance and taste characteristics were good.

Examples 2 to 4 Polyester cast films were obtained in the same manner as in Example 1 except that [η] of the film, the lamination ratio, and the method of adding the antioxidant were changed. Tables 1 and 2 show the results. However, the embodiment
In 2, the obtained cast film is further extended vertically and horizontally biaxially.
After elongation, heat treatment was performed.

In Example 2, since the [η] of the film was as small as 0.69, the impact resistance was slightly lowered. In Example 3, the thickness of the layer B was large and the impact resistance was slightly lowered. In Example 4, when the same antioxidant as the layer A was contained in the layer B at 0.1% by weight, the taste characteristics were lowered.

As a result, the polyester film of the present invention was characterized by having excellent adhesion, impact resistance, taste characteristics, and few defects in the film after molding and heat treatment.

COMPARATIVE EXAMPLE 1 17.5 mol% of isophthalic acid copolymerized polyethylene terephthalate (50 ppm of germanium element,
[Η] = 0.75, diethylene glycol 1.50% by weight, melting point 210 ° C., acetaldehyde amount 37 ppm, carboxyl end group 41 equivalents / ton), isophthalic acid 5 mol% copolymerized polyethylene terephthalate (germanium element amount 42 ppm, [Η] = 0.64, 1.20% by weight of diethylene glycol, melting point 239 ° C., 38 ppm of acetaldehyde, 39 equivalents / ton of carboxyl end groups, 0.1% by weight of silicon oxide particles having an average particle diameter of 6 μm) and an extrusion temperature of At 285 ° C., a copolymerized polyester film was obtained in the same manner as in Example 1. Table 2 shows the results.

As a result, this polyester film
Since the content of diethylene glycol was large and no antioxidant was contained, the film was poor in impact resistance and taste characteristics.

Comparative Example 2 A film was obtained in the same manner as in Example 2 except that the antioxidant was not added, and the impact resistance could not be satisfied.

[0058]

[Table 1]

[Table 2]

[0059]

The polyester film for laminating a metal plate of the present invention has excellent adhesiveness, impact resistance and taste characteristics.
It can be suitably used for metal cans manufactured by molding.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI B29L 9:00 B29L 9:00 (58) Investigated field (Int.Cl. ⁷ , DB name) B32B 15/08 B29C 55/02 -55/20 B32B 27/18 B32B 27/36 C08J 5/18

Claims (3)

(57) [Claims] 1. An A layer mainly composed of polyester having a melting point of 120 to 230 ° C., and a melting point of 231 to 26
A metal plate laminate comprising a laminate of a layer B mainly composed of polyester at 0 ° C. and containing 0.01 to 1% by weight of a diethylene glycol component and 0.001 to 1% by weight of an antioxidant. For polyester film. 2. The polyester film for laminating a metal plate according to claim 1, wherein the layer B contains substantially no antioxidant and only the layer A contains an antioxidant. 3. A polyester film for metal sheet laminate according to claim 1 or 2, characterized in that the intrinsic viscosity [eta] is 0.7 or more films.