JPH07207039A - Polyester film for lamination with metallic sheet - Google Patents

Abstract

PURPOSE:To obtain a polyester film for lamination with a metallic sheet excelling in adhesion, formability, heat resistance, impact resistance and taste characteristics and desirably used for processing a metallic can by laminating a specified polyester film having a specified melting point with a common polyester film. CONSTITUTION:This film is one having a melting point of 120-260 deg.C and containing 0.01-1wt.% diethylene glycol component and 0.001-1wt.% antioxidant. A film prepared by laminating this film (A) with a polyester film (B) mainly consisting of a polyester of a melting point of 231-260 deg.C is preferable in respect that layer A has a function of improving the adhesion to a metallic sheet, and layer B has a function of preventing the inside surface of the can from being damaged by the holder used in baking the can itself after being made. It is desirable from the viewpoint of the taste characteristics that layer B is substantially free from any antioxidant.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyester film for laminating metal plates. More specifically, the present invention relates to a polyester film for laminating metal plates, which has excellent adhesiveness, moldability, impact resistance, and taste characteristics and is suitable for a metal can manufactured by molding.

[0002]

2. Description of the Related Art Conventionally, for the purpose of preventing corrosion, the inner and outer surfaces of metal cans are coated with various thermosetting resins such as epoxy or phenol dissolved or dispersed in a solvent to coat the metal surface. It has been widely practiced. However, such a coating method of a thermosetting resin has a problem that it takes a long time to dry the coating material, productivity is lowered, and environmental pollution is caused by a large amount of organic solvent.

As a method for 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 on the metal plate, which is a material for a metal can, or a laminated metal film. When a metal can is manufactured by drawing or ironing a plate, the polyester film is required to have the following properties.

(1) Excellent adhesion to a metal plate.

(2) Excellent moldability.

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

(4) The scent component of the contents of the can is not adsorbed on the polyester film, and 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, Japanese Patent Laid-Open No. 64-22530 discloses a polyester film having a specific density and plane orientation coefficient, and Japanese Laid-Open Patent Publication No. 2-57339. Discloses a copolyester film having a specific crystallinity. However, these proposals are not ones that can comprehensively satisfy the various required characteristics described above, and are particularly satisfactory in terms of impact resistance and taste characteristics after heat history in the can making process. I couldn't say that there was.

[0009]

The object of the present invention is to eliminate 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. Another object of the present invention is to provide a copolymerized polyester and film for a metal plate laminate, which has excellent impact resistance and taste characteristics and is suitable for a metal can produced by molding.

[0010]

The above-mentioned object of the present invention is to have a melting point of 120 to 260 ° C., a diethylene glycol component of 0.01 to 1% by weight, and an antioxidant of 0.00
It can be achieved by a polyester film for laminating metal plates, which is characterized by containing 1 to 1% by weight.

The polyester in the present invention is a polymer composed of a dicarboxylic acid component and a glycol component, and examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid and diphenoxy. Aromatic dicarboxylic acids such as ethanedicarboxylic acid, 5-sodium sulfoisophthalic acid, phthalic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, 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, examples of the glycol component include 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 these glycol components, ethylene glycol is preferable from the viewpoint of impact resistance and taste characteristics. Two or more kinds of these dicarboxylic acid components and glycol components may be used in combination.

Further, a polyfunctional compound such as trimellitic acid, trimesic acid and trimethylolpropane may be copolymerized with the copolyester as long as the effect of the present invention is not impaired.

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 adhesiveness with the metal plate. Preferred examples include polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate and copolymerized polyesters thereof. When copolymerizing the above-mentioned acid component or glycol component with these polyesters, all acid components constituting the polyester are preferable. And / or 1-40 mol% of the total glycol component is preferably copolymerized from the viewpoint of adhesiveness to the metal plate, further preferably 5-30 mol%, particularly preferably 8-20 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 due to crystallization of the film being promoted in the manufacturing process of the metal can. On the other hand, if it exceeds 40 mol%, the melting point becomes low and the impact resistance is poor. Examples of preferred copolymerization components include isophthalic acid and butanediol, with isophthalic acid being particularly preferred.

In the present invention, 0.01 to 1% by weight of a diethylene glycol component is contained in order to prevent the impact resistance from being deteriorated due to heat history such as drying and printing during the can making process.
It is necessary to contain, and preferably 0.01 to
It is 0.8% by weight, more preferably 0.01 to 0.6% by weight, and particularly preferably 0.01 to 0.5% by weight. When the content of the diethylene glycol component is less than 0.01, the polymerization process becomes complicated, which is not preferable in terms of cost. When it exceeds 1% by weight, the polyester is deteriorated due to the heat history in the can making process and the impact resistance of the film is increased. It is not preferable because it gets worse. Diethylene glycol is produced as a by-product during the production of polyester, but in order to reduce the amount to 1% by weight or less, the polymerization time is shortened, or the amount of antimony compound or germanium compound used as a polymerization catalyst is limited, or liquid phase polymerization is used. Examples of the method include, but are not limited to, a method of combining and solid phase polymerization.

Further, in the present invention, the impact resistance after being subjected to a heat history of 200 ° C. or higher and the impact resistance after being treated with a pressurized steam (retort treatment) at about 120 ° C. are improved. Must contain 0.001 to 1% by weight of an antioxidant. The amount of antioxidant is 0.00
If it is less than 1% by weight, the impact resistance is not improved, and if it exceeds 1% by weight, the taste characteristics are deteriorated, which is not preferable.

The type of antioxidant is not particularly limited, and known antioxidants classified into hindered phenols, hydrazines, phosphites and the like can be preferably 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 preferably used.

A layer mainly composed of polyester having a melting point of 120 to 230 ° C. and melting point of 231 to 260 ° C.
The laminated film obtained by laminating the B layer containing polyester as a main constituent component not only improves the adhesiveness between the A layer and the metal plate, but also retains the B layer when baking the can after making the can. It 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 B layer contains substantially no antioxidant, and only the A layer contains an antioxidant.

In the present invention, in the film obtained by laminating the layer A having polyester having a melting point of 100 to 230 ° C. as a main constituent, the B layer having polyester having a melting point of 231 ° C. to 260 ° C. as a main constituent, The composition, catalyst, amount of diethylene glycol, and amount of carboxyl end groups in each layer may be different. When the edge of the film is collected, it is preferable to collect it in the A layer from the viewpoint of taste characteristics.

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

The intrinsic viscosity [η] is preferably 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 the taste characteristics, the content of acetaldehyde in the polyester is 50 ppm or less,
Preferably 40 ppm or less, more preferably 30 pp
m or less, particularly preferably 20 ppm or less. If the acetaldehyde content exceeds 50 ppm, the taste characteristics are poor. The content of acetaldehyde in the film is 50 pm
The following method is not particularly limited, for example, in order to remove acetaldehyde generated by thermal decomposition when producing a polyester by a polycondensation reaction, etc., in order to remove the polyester under reduced pressure or in an inert gas atmosphere, A method of heat-treating at a temperature below the melting point, preferably a method of solid-phase polymerizing polyester at a temperature of 150 ° C. or higher and a temperature below the melting point under reduced pressure or in an inert gas atmosphere, and a method of melt film formation using a vent type extruder Extrusion temperature when melting and extruding polyester is + 40 ℃
And preferably a melting point + 30 ° C. or less, and a method of extruding in a short time.

From the viewpoint of taste characteristics, the polyester of the present invention preferably contains 1 to 500 ppm of a germanium element, more preferably 5 to 300 ppm, and particularly preferably 10 to 100 ppm. When the amount of germanium element is less than 1 ppm, the effect of improving taste characteristics is not sufficient,
On the other hand, when it exceeds 500 ppm, foreign matter is generated in the polyester, and impact resistance is deteriorated, and taste characteristics are deteriorated.
The polyester of the present invention can have improved taste characteristics by containing the above-mentioned specific amount of 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. Examples of such a method include a method of directly adding a powder of a germanium compound, or a method of dissolving a germanium compound in a glycol component which is a starting material of polyester, as described in JP-B-54-22234. And the like. Examples of the germanium compound include germanium dioxide, germanium hydroxide containing water of crystallization, or germanium tetramethoxide, germanium tetraethoxide, germanium tetrabutoxide, germanium alkoxide compounds such as germanium ethylene glycol oxide, germanium phenolate, germanium β-
Examples thereof include germanium phenoxide compounds such as naphtholate, germanium phosphate, phosphorus-containing germanium compounds such as germanium phosphite, and germanium acetate. Of these, germanium dioxide is preferable.

Further, when the carboxyl terminal group of the polyester film of the present invention is 45 equivalents / ton or less, it is preferable in terms 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 from the viewpoint of film recoverability and impact resistance.

The polyester of the present invention has a content of the oligomer in the polyester of 0.8% by weight from the viewpoint of taste characteristics.
The amount is preferably below, more preferably 0.7% by weight or less, and particularly preferably 0.6% by weight or less. Content of oligomer in copolymerized polyester is 0.8% by weight
If it exceeds, the taste characteristics are deteriorated, which is not preferable. The method for adjusting the content of the oligomer in the polyester to 0.8% by weight or less is not particularly limited, but the same method as the method for reducing the acetaldehyde content in the above-mentioned copolymerized polyester should be adopted. Can be achieved with.

The polyester of the present invention can be produced by any conventionally known method and is not particularly limited. For example, a case will be described where polyethylene terephthalate is copolymerized with an isophthalic acid component and germanium dioxide is added as a germanium compound. A terephthalic acid component, an isophthalic acid component and ethylene glycol are transesterified or esterified, and then germanium dioxide is added, followed by polycondensation reaction at a high temperature and reduced pressure until a constant diethylene glycol content is obtained, and a germanium element-containing polymer To get Then, the obtained polymer is subjected to a solid-state polymerization reaction at a temperature below its melting point under reduced pressure or in an inert gas atmosphere to reduce the content of acetadeldide to obtain a predetermined intrinsic viscosity [η] and a carboxyl end group. Etc. can be mentioned.

In producing the polyester of the present invention,
Conventionally known reaction catalysts and anti-coloring agents can be used, and examples of the reaction catalysts include alkali metal compounds, alkaline earth metal compounds, zinc compounds, lead compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, titanium. Examples of the anti-coloring agents such as compounds include phosphorus compounds.

The copolymerized polyester of the present invention contains 0.001% of inorganic particles and / or organic particles having an average particle diameter of 0.01 to 8 μm in order to improve the handling property of the film and the processability of the metal can. 10 to 10% by weight is preferable, and the average particle size is 0.1 to 5
Inorganic particles and / or organic particles having a size of 0.005 μm
It is preferable that the content is 3% by weight. Examples of the inorganic particles and / or organic particles include wet and dry silica, colloidal silica, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, mica, kaolin, clay and the like inorganic particles and styrene, silicone, acrylic acid and the like. Examples thereof include organic particles having as a constituent. Among them, wet and dry colloidal silica, inorganic particles such as alumina and styrene, silicone, acrylic acid, methacrylic acid, polyester,
Examples thereof include organic particles having divinylbenzene or the like as a constituent component. Two or more kinds of these inorganic particles and / or organic particles may be used in combination.

The particles may be added to either the A layer or the B layer, but it is preferable to add the particles to the B layer for ease of handling. On the other hand, particles may be added to the layer A as long as the characteristics are not impaired in terms of recovery. In addition, when particles are not contained, when the polymer is melt extruded and solidified by a casting drum, a method in which the layer B is on the drum surface is roughened and the film is pressed with air to solidify rapidly is adopted. May be.

Further, in the production of the polyester film of the present invention, additives such as a plasticizer, an antistatic agent, a weather resistance agent and a terminal blocking agent can be appropriately used if necessary.

The film made of the copolyester in the present invention may be an unstretched sheet or a uniaxially or biaxially stretched film. In a molding method such as ironing molding in which the moldability of the film is important, an unstretched sheet, or a plane orientation coefficient fn obtained from the refractive index (Nx, Ny, Nz) in the longitudinal direction, the width direction and the thickness direction = (Nx + Ny) / 2-Nz
A stretched film having a value of 0 to 0.12 is preferable, and an unstretched film is particularly preferable in terms of moldability.

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

Polyester A containing 17.5 mol% of isophthalic acid containing 0.1% by weight of antioxidant Polyethylene terephthalate (germanium element content 40 pp
m, [η] = 0.85, diethylene glycol 0.92
% By weight, melting point 213 ° C., acetaldehyde amount 12 pp
m, carboxyl terminal group 21 equivalents / ton), polyester B as isophthalic acid 5 mol% copolymerized polyethylene terephthalate (germanium element amount 42 ppm, [η]
= 0.90, diethylene glycol 0.89% by weight, melting point 240 ° C, acetaldehyde amount 10 ppm, carboxyl end group 20 equivalents / ton) twin-screw vent type separate extruder (extruder temperature is set to melting point + 25 ° C) Then, the mixture is melted and then laminated in two layers by a feed block, discharged from an ordinary die and 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 if necessary and wound up.

The polyester cast film may be biaxially stretched simultaneously or sequentially. In the case of sequential biaxial stretching, it is also possible to perform stretching in the longitudinal direction or the width direction twice or more. The stretching 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, etc. 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 or may be the same. The stretching temperature may be any temperature as long as it is in the range of the glass transition temperature of the polyester or more and the crystallization temperature or less, but it is usually 80 to 150.
C is preferred. Further, the film can be heat-treated after the biaxial stretching. 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 above the crystallization temperature of the polyester and below the softening point, but it is preferably 120 to 240 ° C. The heat treatment time may be arbitrary, but it is usually preferably 1 to 60 seconds. The heat treatment may be performed while relaxing the film in the longitudinal direction and / or the width direction thereof.

The metal plate of the present invention is not particularly limited,
A metal plate made of iron, aluminum or the like is preferable in terms of formability. Furthermore, in the case of a metal plate made of iron, an inorganic oxide coating layer that improves the adhesion and corrosion resistance on the surface of the metal plate, 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, chromate treatment or chromium chromate treatment may be provided. Particularly, in terms of metallic chromium, 6.5 to 6.5 as chromium
150 mg / m ² of hydrated chromium oxide is preferable, and a spreadable metal plating layer such as nickel, tin, zinc, aluminum, gun metal or brass may be further provided. For tin plating 0.5-15 / m ^2, it is preferable to have a plating amount when nickel or aluminum 1.8~20g / m ^2.

The metal laminating film 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. Also, good metal adhesion for covering the lid part 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. Therefore, a colorant can be blended in the polyester layer, and as the colorant, white type, red type, etc. are preferably used, and titanium oxide, zinc white, lithophone,
5 to 50 colorants selected from inorganic or organic pigments
It is desirable to add it by weight%, preferably 15-40% by weight. If the addition amount is less than 5% by weight, the color tone and the whiteness are inferior, which is not preferable. You may use together a pinking agent, a bluing agent, etc. as needed.

[0038]

[Characteristic Evaluation Method] The characteristics of the polyester film were measured and evaluated by the following methods.

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

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

(3) Intrinsic viscosity of polyester Dissolve the polyester in orthochlorophenol and prepare 25
It was measured at ° C.

(4) Melting Point of Polyester A polyester chip was crystallized and subjected to a differential scanning calorimeter (DSC-2 type manufactured by Perkin Elmer Co.) at 10 ° C. /
It was measured at a temperature rising rate of min.

(5) Plane Orientation Coefficient A sodium D line (wavelength: 589 nm) was used as a light source and an Abbe refractometer was used for measurement. The plane orientation coefficient fn = (Nx + Ny) / 2-Nz obtained from the refractive indices (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 heated and pressure-laminated at a temperature of 180 to 230 ° C., and the ironing machine [molding ratio (maximum thickness / minimum thickness)
= 3.0], and bottom molding etc. is performed.
I got a necking can. After can making, it was air-baked under the condition of 220 ° C for 10 minutes, and after air-baked, it was retort-treated at 120 ° C x 30 minutes, filled with commercially available oolong tea, and left at 20 ° C for 24 hours. After impacting each with 5 points with a punch, remove the contents, mask the inner surface of the can with a wax, put 1% saline in the cup, and apply a voltage of 6 V to the electrode in the saline and the metal can to apply current. Read the value.

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

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

Further, a fragrance aqueous solution (d-
Limonene (20 ppm aqueous solution) was put therein, and after sealing, the mixture was left for 1 month, then opened and the sensory test evaluated the change of odor according to the following criteria.

Class A: No change in odor is observed B Class: Slight change in odor C Class: Change in odor

[0049]

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

Example 1 17.5 mol% of isophthalic acid copolymerized polyethylene terephthalate (germanium element content 40 ppm, [η] = 0.0) added with 0.1% by weight of antioxidant IRGANOX1010 manufactured by Ciba-Geigy Co., Ltd. as polyester A.
85, diethylene glycol 0.90% by weight, melting point 21
3 ° C., acetaldehyde amount 8 ppm, carboxyl terminal group 21 equivalent / ton), as polyester B 5 mol% isophthalic acid copolymerized polyethylene terephthalate (germanium element amount 42 ppm, 0.5 wt% silicon oxide particles having an average particle diameter of 2 μm, [η ] = 0.90, diethylene glycol 0.89% by weight, melting point 240 ° C., acetaldehyde amount 6 ppm, carboxyl end group 20 equivalent / ton) Separate twin-screw vent type extruder (extruder temperature is melting point +2)
Set to 5 ° C, supplied for an average residence time of about 20 minutes) and melted,
Then two layers (polyester A
Layer / polyester B layer = 9/1), the mixture was discharged from an ordinary die and cooled and solidified by a cooling drum to obtain a cast film of 30 μm. The obtained film was 0.90% by weight of diethylene glycol and 12 p of acetaldehyde.
pm, [η] = 0.78, and oligomer was 0.6% by weight.

The physical properties of the two-layer laminated cast film thus obtained are shown in Table 1. As you can see from the table, the adhesiveness,
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 the [η] of the film, the lamination ratio, and the addition method of the antioxidant were changed. The results are shown in Tables 1 and 2.

In Example 2, the [η] of the film was as small as 0.69, and therefore the impact resistance was slightly lowered. In Example 3, the B layer was thick and the impact resistance was slightly lowered. In Example 4, when the B layer contained 0.1% by weight of the same antioxidant as the A layer, the taste characteristics deteriorated.

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

Comparative Example 1 As layer A, 17.5 mol% of isophthalic acid copolymerized polyethylene terephthalate (germanium element content 50 ppm,
[Η] = 0.75, diethylene glycol 1.50% by weight, melting point 210 ° C., acetaldehyde amount 37 ppm, carboxyl end group 41 equivalent / ton), isophthalic acid 5 mol% copolymerized polyethylene terephthalate as layer B (germanium element amount 42 ppm, [Η] = 0.64, diethylene glycol 1.20% by weight, melting point 239 ° C., acetaldehyde amount 38 ppm, carboxyl end group 39 equivalent / ton, silicon oxide particles having an average particle size of 6 μm 0.1% by weight) At 285 ° C., a copolyester film was obtained in the same manner as in Example 1. The results are shown in Table 2.

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

Comparative Example 2 When a film was obtained in the same manner as in Example 2 except that no antioxidant was added, the impact resistance could not be satisfied.

[0058]

[Table 1]

[Table 2]

[0059]

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

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area C08K 5/05 C08L 67/02 KJU

Claims (4)

[Claims] 1. A polyester film for laminating metal plates, which has a melting point of 120 to 260 ° C., contains 0.01 to 1% by weight of a diethylene glycol component, and contains 0.001 to 1% by weight of an antioxidant. 2. A layer mainly composed of polyester having a melting point of 120 to 230 ° C. and a melting point of 231 to 260
For laminating a metal plate, which comprises laminating a layer B containing polyester at a temperature of ℃ as a main constituent, containing 0.01 to 1% by weight of a diethylene glycol component and 0.001 to 1% by weight of an antioxidant. Polyester film. 3. The polyester film for metal plate laminating according to claim 2, wherein the layer B contains substantially no antioxidant, and the layer A contains an antioxidant. 4. The polyester film for metal plate lamination according to claim 1, wherein the intrinsic viscosity [η] is 0.7 or more.