JPH11216805A - Laminate and container using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal-polyester laminate having a combination of an improved impact resistance (particularly dent resistance), processability and resistance to contents, and a seamless container formed from the laminate. SOLUTION: In the laminate comprising a metal base body and a resin layer composed mainly of a polyester, the polyester satisfies the following equations: T1 >=70, 50>=T2 >=10, T3 <=-60, and T1 -T2 >=25, where T1 , T3 , and T2 show a high temperature side peak temperature, a low temperature side peak temperature, and an intermediate peak temperature, respectively in a dynamic viscoelasticity test. The laminated material comprises a complex polyester film having a loss modulus satisfying such equations as shown above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate comprising a metal substrate and a polyester film laminated thereon and a seamless container formed by drawing or further ironing the laminate. More specifically,
The present invention relates to a laminate excellent in the combination of impact resistance (dent resistance), workability and content resistance, and a seamless container formed from the laminate.

[0002]

2. Description of the Related Art Conventionally, as a side seamless can (side seamless can), a metal material such as an aluminum plate, a tin plate or a tin-free steel plate is provided by at least one step between a drawing die and a punch. By drawing, a cup consisting of a body part having no side seam and a bottom part connected to the body part without a seam is formed, and then, if desired, an ironing punch and a die are formed on the body part. It is known that the body of the container is thinned by ironing between them.
In addition, instead of ironing, it is already known that the side wall portion is thinned by bending and stretching at a curvature corner portion of a redrawing die (Japanese Patent Publication No. 56-501442).

As an organic coating method of a side seamless can, there is a method of applying an organic paint to a molded can which is widely used in general, and a method of laminating a resin film on a metal material before molding in advance. Known, Tokubiko Sho 59-3
No. 4580 describes the use of a metal material laminated with a polyester film derived from terephthalic acid and tetramethylene glycol. Also, when producing redrawn cans by bending and stretching,
It is also known to use a coated metal plate of vinyl organosol, epoxy, phenolics, polyester, acrylic or the like.

There have been many proposals for the production of polyester-coated metal sheets, for example, see Japanese Patent Application Laid-Open No. 51-4229.
In JP-A-6-172556, a coating film composed of polyethylene terephthalate having a biaxial orientation remaining on the surface is described.
It has been proposed to use five or more polyester films for metal lamination.

JP-A-3-101930 discloses a lamination of a metal plate, a polyester film layer mainly composed of ethylene terephthalate units and, if necessary, an adhesive primer layer interposed between the metal plate and the polyester film. Wherein the polyester film layer has the formula Rx = IA / IB, where IA is parallel to the polyester film surface and has a plane spacing of about 0.34 nm (CuKα X-ray diffraction angle is from 24 ° to 2 °).
8 ゜) X-ray diffraction intensity by the diffraction plane, IB is about 0.39 nm (Cu
The X-ray diffraction intensity defined by the diffraction surface having a Kα X-ray diffraction angle of 21.5 ° to 24 °) is 0.1.
A coated metal plate for drawn cans, wherein the coated metal plate is comprised of a film layer having an anisotropy index of in-plane orientation of crystal of 30 or less in the range of from 15 to 15. Is described in Japanese Patent Application Laid-Open No. H11-150572, which describes a thinned drawn can which is formed by drawing and redrawing, and at the time of redrawing, the side wall portion of the can body is thinned by bending and stretching.

[0006] It is already known to use polyester laminates and blends of various compositions as the polyester. For example, Japanese Patent Application Laid-Open No. Hei.
A polyester composite film comprising a layer, a layer B and a layer A, wherein the layer A is polyethylene terephthalate isophthalate having a melting point of 210 to 230 ° C. A polyester resin having a glass transition point of 40 ° C. or less in which 5 to 50 mol% contains an aliphatic dicarboxylic acid residue having 10 or more carbon atoms, and 50 mol% or more of the total alcohol component comprises ethylene glycol residues. A polyester composite film for metal bonding, characterized by the above, is described. JP-A-8-230130 discloses a laminate comprising a metal substrate and a biaxially stretched polyester film layer thermally bonded to the metal substrate, wherein the polyester film comprises (i)
(Ii) an ester unit derived from (a) butylene glycol and an aromatic dibasic acid, and (b) an ester unit derived from butylene glycol and an aliphatic dibasic acid. 9
A laminate comprising: a copolymer containing a molar ratio of 0:10 to 40:60 and (i) :( ii) in a weight ratio of 70:30 to 10:90. A seamless container formed by drawing or further ironing the laminate is described.

[0007]

The proposal recognized in the above prior art is to apply a resin film to a metal material before molding, and to apply a coating film baking furnace or a paint exhaust gas treatment facility as in a normal coating process. Is required, there is no air pollution, and there is no need to apply coating treatment to the molded body. However, various characteristics of the can, especially impact resistance (dent resistance), workability And there is room for improvement in terms of content resistance and the like.

[0008] The polyester layer used in the laminate has a sufficient barrier property against corrosive components in the contents, and the fact that it does not adsorb flavor components in the contents is fundamental in terms of the storage stability of the contents. However, there is a problem that it is not always easy to achieve both the content resistance and the impact resistance and workability.

Practical impact resistance required for actual canned products includes what is called dent resistance. This means that even if the canned product falls or collides with each other and a dent called a dent occurs on the canned product, the adhesion and coverage of the coating can be completely maintained. Is required. That is, if the coating peels off or pinholes or cracks enter the coating in the dent test, metal elution or leakage due to pitting corrosion occurs from this portion, causing a problem of losing the preservability of the contents. . In the case of the above-mentioned polyester having excellent content resistance, the polyester generally lacks the property of absorbing or relaxing the impact in the dent test, and the provision of these properties is an important issue.

In the case of a seamless can formed from a polyester laminate, draw-forming and ironing of the seamless can are not only severe, but the neck-in process and the flange Secondary processing such as processing and winding processing is indispensable, and a laminated body processed into a seamless can must still maintain workability enough to withstand these processings. In the case of the polyester having excellent content resistance described above, it is customary to undergo a high degree of molecular orientation during processing into a seamless can. In such a highly oriented state, generally, the processability is considerably reduced. Furthermore, in the case of cans, the effects of heat treatment on the coating cannot be avoided. That is, it is common to print on the outer surface of the can to display the contents and the like, and the influence of heating for printing the printing ink,
Occurs in polyester films. Polyester tends to crystallize (become brittle) by heating, which reduces dent resistance and also reduces workability in neck-in processing, winding processing, and the like.

Accordingly, an object of the present invention is to provide a metal-polyester laminate excellent in the combination of impact resistance (particularly, dent resistance), workability and content resistance, and a seamless container formed from the laminate. To be.

Another object of the present invention is to suppress embrittlement due to crystallization and to provide excellent dent resistance and workability despite high degree of drawing or ironing and heat treatment during or after can making. Another object of the present invention is to provide a metal-polyester laminate and a seamless container comprising the same, which maintain the combination of the content and the content resistance.

[0013]

According to the present invention, in a laminate comprising a metal substrate and a resin layer mainly composed of polyester, the polyester has the following formula: T ₁ ≧ 70７０ (I) 50 ≧ T ₂ ≧ 10 ‥ (II) T ₃ ≦ −60 ‥ (III) and T ₁ −T ₂ ≧ 25 IV (IV) wherein T ₁ , T _3, and T ₂ are the same as those in the dynamic viscoelasticity test.
A laminate is provided, comprising a composite polyester film having a loss modulus that satisfies a high peak temperature, a low peak temperature, and an intermediate peak temperature. According to the present invention, there is further provided a seamless container characterized by being formed by drawing or further ironing the laminate. In the present invention: The composite polyester film is derived from (1) a surface layer composed of a polyester mainly composed of ethylene terephthalate or ethylene naphthalate, (2) terephthalic acid or naphthalenedicarboxylic acid and an aliphatic dibasic acid and ethylene glycol and butylene glycol. 1. A laminated film comprising an intermediate layer composed of a copolymerized polyester or a polyester composition and (3) a base layer composed of a polyester mainly composed of ethylene terephthalate or ethylene naphthalate. The intermediate layer comprises: (i) a polyester mainly composed of an ethylene terephthalate unit or an ethylene naphthalate unit; (ii) (a) an ester unit derived from butylene glycol and an aromatic dibasic acid; and (b) butylene glycol. (I) :( ii) = 70: 30 to 10:90 with a copolymerized polyester containing ester units derived from an aliphatic dibasic acid and a molar ratio of 85:15 to 50:50.
2. It is formed from a blend containing a weight ratio of 3. the intermediate layer occupies 90 to 50% by weight of the composite polyester film; It is preferable that the composite film is a biaxially stretched film.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Function] The laminate of the present invention is formed of a metal substrate and a resin layer mainly composed of polyester, and the polyester is represented by the above formula (I) to (IV), that is, the following formula T ₁ ≧ 70 ‥ (I) 50 ≧ T ₂ ≧ 10 ‥ (II) T ₃ ≦ −60 ‥ (III) and T ₁ −T ₂ ≧ 25 ‥ (IV) where T ₁ , T ₃ and T ₂ are dynamic. Dynamic viscoelasticity test,
It is a remarkable feature that the composite polyester film has a loss elastic modulus that satisfies a high peak temperature, a low peak temperature, and an intermediate peak temperature.

FIGS. 1 to 4 of the accompanying drawings are graphs in which a dynamic viscoelasticity test of a polyester layer was performed on various polyester metal laminates, and a relationship between a temperature and a loss modulus was plotted. Curve A in FIG. 1 shows that the intermediate peak T ₂ does not exist, and the low-temperature peak T ₃ is also out of the range of the present invention. Such a polyester layer has excellent content resistance. However, the dent resistance and the workability are remarkably inferior (see Experimental Example 7 described later). on the other hand,
The curve B in FIG. 2 shows the high temperature side peak T ₁ and the low temperature side peak T _1.
3 is within the ranges of the present invention, which intermediate peak T ₂ is not present, in such a polyester layer, although excellent in content resistance and dent resistance, workability is markedly inferior (See Experimental Example 8 described later). Also,
Curve C in FIG. 3 shows the high temperature side peak T ₁ and the low temperature side peak T
₃ each satisfy the scope of the present invention, but have an intermediate peak T ₂
Does not satisfy the range of the present invention, and the separation between the high temperature side peak T ₁ and the intermediate peak T ₂ does not satisfy the above formula (IV). In such a polyester layer, the content resistance and the dent resistance Although the workability was excellent, the workability was poor (see Experimental Example 9 described later). On the other hand, the curve D in FIG. 4 shows that the high-temperature side peak T ₁ , the low-temperature side peak T _3, and the intermediate peak T ₂ satisfy all of the expressions (I) to (IV). The polyester layer is excellent in a combination of content resistance, dent resistance, and workability (see Experimental Example 1 described later).

In the present invention, it is extremely important that the high-temperature peak T ₁ of the loss modulus in the dynamic viscoelasticity test falls within the range of the formula (I) in terms of the content resistance. If the composition does not satisfy (I), the corrosion resistance becomes insufficient or the contents tend to be off-flavored. It is extremely important that the low-temperature peak T ₃ of the loss modulus in the dynamic viscoelasticity test falls within the range of the formula (III) in terms of impact resistance (dent resistance). If the resin does not satisfy (III), the polyester layer will be peeled or cracked by the dent test, and metal elution or pitting will occur from this portion. Further, the intermediate peak T ₂ of the loss modulus in the dynamic viscoelasticity test is given by the formula (II)
And the range satisfying the formula (IV) is extremely important from the viewpoint of workability, and the intermediate peak is determined by the formula (II) or the formula (IV).
If the condition is not satisfied, cracks, pinholes, and the like will occur in the secondary worked portions such as the neck-in worked portion and the flange portion, and metal elution and pitting will occur from these portions.

In the present invention, as described above,
By selecting a composite polyester film in which the high temperature side peak T ₁ , the low temperature side peak T ₃ and the intermediate peak T _{2 of the} loss elastic modulus satisfy all of the above formulas (I) to (IV),
It is possible to obtain a laminated body for cans having an excellent combination of content resistance, dent resistance and workability. The polyester film used in the present invention is specified as a composite polyester film because it is difficult to satisfy all of the formulas (I) to (IV) with a polyester film having a single composition. By compounding the polyester having the composition, all of the above formulas (I) to (IV) can be satisfied.

Generally, the high temperature peak of the loss modulus satisfying the above formula (I) is preferably derived from the surface polyester of the composite polyester film, but is present in a layer other than the surface layer, for example, an intermediate layer. No problem.

On the other hand, the low-temperature peak of the loss modulus satisfying the above formula (III) is derived from a layer other than the surface layer of the composite polyester film, particularly, the polyester in the intermediate layer, so that the content resistance is excellent. It is preferable to improve the impact resistance while maintaining the level at an appropriate level.

Further, the intermediate peak of the loss elastic modulus satisfying the above formulas (II) and (IV) is derived from a layer other than the surface layer of the composite polyester film, particularly, the polyester of the intermediate layer. It is preferable to improve workability while maintaining physical properties at an excellent level.

The preferred composite polyester film used in the present invention comprises (1) a surface layer composed of a polyester mainly composed of ethylene terephthalate or ethylene naphthalate, (2) terephthalic acid or naphthalenedicarboxylic acid and an aliphatic dibasic acid and ethylene. An intermediate layer comprising a copolymerized polyester or a polyester composition derived from glycol and butylene glycol; and (3) a base layer comprising a polyester mainly composed of ethylene terephthalate or ethylene naphthalate. The surface layer and the underlayer give a high-temperature peak of the loss modulus, and the intermediate layer gives a low-temperature peak and a middle peak of the loss modulus. This laminated film contains polyester mainly composed of ethylene terephthalate or ethylene naphthalate on the inner and outer surfaces and has a symmetrical three-layer structure, so that it has excellent film-forming properties and is easy to laminate with a metal substrate. The obtained laminate is most excellent in the combination of content resistance, dent resistance and workability.

The intermediate layer of the composite film used in the present invention comprises:
(I) a polyester mainly composed of an ethylene terephthalate unit or an ethylene naphthalate unit, (ii) (a) an ester unit derived from butylene glycol and an aromatic dibasic acid, and (b) butylene glycol and an aliphatic dibasic acid. 85:15 to 5 with the ester unit derived from
The dent resistance and the processability are such that the copolymer is formed from a blend containing a copolymerized polyester containing a molar ratio of 0:50 and (i) :( ii) in a weight ratio of 70:30 to 10:90. Is most preferred.

Further, it is preferable that the intermediate layer occupies 90 to 50% by weight, particularly 85 to 50% by weight of the composite polyester film, from the viewpoint of the balance between the content resistance, the dent resistance and the processability.

The composite film used in the present invention is preferably a biaxially stretched film in order to further improve the content resistance of the final seamless can and to improve the heat resistance of the can.

[Laminate] In FIG. 5, which shows an example of the cross-sectional structure of the laminate of the present invention, the laminate 1 comprises a metal substrate 2 and a composite polyester layer 3 located at least on the inner surface side. An outer coating 4 is formed on the metal substrate 2, and the outer coating 4 may be the same as the composite polyester layer 3, or may be a normal can coating or a resin (polyester) film coating. You may. The composite polyester layer 3 includes a surface layer 5, an intermediate layer 6, and a base layer 7.

In FIG. 6 showing another example of the cross-sectional structure of the laminate, the same as in FIG. 5 except that an adhesive primer layer 8 is provided between the composite polyester layer 3 and the metal base 2. is there.

[Composite polyester layer]
In the dynamic viscoelasticity test, the synthetic polyester layer
High-temperature side peak T satisfying (I) to (IV)₁, Low temperature side
Peak T_ThreeAnd intermediate peak T _TwoIt shows.

Particularly preferred composite polyester layers are (1)
A surface layer composed of a polyester mainly composed of ethylene terephthalate or ethylene naphthalate; (2) an intermediate layer composed of a copolymerized polyester or polyester composition derived from terephthalic acid and an aliphatic dibasic acid and ethylene glycol and butylene glycol; (3) An underlayer composed of a polyester mainly composed of ethylene terephthalate or ethylene naphthalate. This example will be described below, but the present invention is never limited to a composite polyester having this layer structure and composition. It is not something.

(A) Surface layer and underlayer polyester: The ethylene terephthalate-based or ethylene naphthalate-based crystalline polyester used in the present invention contains 70% by mole or more, particularly 80% by mole or more of the ester repeating unit. Occupies terephthalate units or ethylene naphthalate units. In the case of an ethylene terephthalate-based polyester, a crystalline polyester having a glass transition point (Tg) of 70 to 90 ° C. and a melting point (Tm) of 210 to 260 ° C. is preferable. Homopolyethylene terephthalate is preferred from the viewpoint of heat resistance, but a copolymerized polyester containing a small amount (20 mol% or less) of an ester unit other than the ethylene terephthalate unit may also be used. Whether or not the polyester is crystalline can be confirmed by showing a clear crystal melting peak in differential thermal analysis. This is the same for the copolyester. on the other hand,
In the case of ethylene naphthalate-based polyester, the glass transition point (Tg) is 100 to 130 ° C., particularly 110 to 1
Crystalline polyesters having a melting point (Tm) of from 210 to 270 ° C. at 30 ° C. are preferred. Homopolyethylene naphthalate is preferred in terms of the content resistance and heat resistance, but a small amount of ester unit other than ethylene naphthalate unit (2
(0 mol% or less).

Examples of dibasic acids other than terephthalic acid and naphthalene 2,6-dicarboxylic acid include isophthalic acid, orthophthalic acid, P-β-oxyethoxybenzoic acid, diphenoxyethane-4,4'-dicarboxylic acid, Preferred is at least one dibasic acid selected from the group consisting of sodium sulfoisophthalic acid, hexahydroterephthalic acid, adipic acid, sebacic acid, trimellitic acid, and pyromellitic acid. Of course, naphthalene 2,6-dicarboxylic acid can be used as the copolymerized dibasic acid component for terephthalic acid, and terephthalic acid can be used as the copolymerized dibasic acid component for naphthalene 2,6-dicarboxylic acid. Ethylene terephthalate-based polyester containing isophthalic acid as a copolymer component is excellent in content resistance, content flavor retention, and the like.

The diol component is preferably composed of only ethylene glycol, but other diol components such as propylene glycol, 1,4-butanediol, diethylene glycol, and the like may be used within a range not to impair the essence of the present invention. , 6-hexylene glycol, pentaerythritol, dipentaerythritol, cyclohexane dimethanol, bisphenol A ethylene oxide adduct or the like, or two or more thereof may be contained.

The crystalline ethylene terephthalate or ethylene naphthalate polyester used has a molecular weight sufficient to form a film, generally 0.55 to 1.5.
Particularly, those having an intrinsic viscosity of 0.6 to 1.5 are preferable.
The measurement of the intrinsic viscosity is performed by a method described later.

(B) Intermediate layer polyester: The intermediate layer polyester used in the present invention comprises a copolymerized polyester or a composition derived from the above-mentioned dibasic acid component and diol component, and (i) ethylene terephthalate unit or A polyester mainly composed of ethylene naphthalate units; (ii) an ester unit derived from (a) butylene glycol and an aromatic dibasic acid; and (b) an ester derived from butylene glycol and an aliphatic dibasic acid. (I) :( ii) = 70: 30 to 10: 9 with a copolymerized polyester containing the units in a molar ratio of 85:15 to 50:50.
Since it is preferable to be formed from a blend containing at a weight ratio of 0, this example will be described, but it is needless to say that the present invention is not limited to this example. The component (i) of the intermediate layer polyester composition is as described above.

The copolymerized polyester used for the intermediate layer is
(a) an ester unit derived from butylene glycol and an aromatic dibasic acid and (b) an ester unit derived from butylene glycol and an aliphatic dibasic acid in a molar ratio of 85:15 to 50:50. It is a copolymerized polyester containing. The above-mentioned copolymerized polyester contributes to giving an intermediate peak of the loss elastic modulus satisfying the formulas (II) and (IV) and a low-temperature side peak of the loss elastic modulus satisfying the formula (III), and has an impact resistance and a processability. Helps improve sex. In particular, an intermediate peak satisfying the formulas (II) and (IV) is useful for improving workability.

As the aromatic dibasic acid constituting the ester unit (a), terephthalic acid, isophthalic acid, orthophthalic acid, P-β-oxyethoxybenzoic acid, naphthalene 2,6-dicarboxylic acid, diphenoxyethane-4 , 4 '
-Dicarboxylic acid, 5-sodium sulfoisophthalic acid and the like, with terephthalic acid being preferred.

Examples of the aliphatic dibasic acid component constituting the ester unit (b) include succinic acid, azelaic acid, adipic acid, pimelic acid, suberic acid, sebacic acid, dodecandioic acid, tetradecandioic acid, dimer acid and the like. Long-chain aliphatic dibasic acids are preferred, and dicarboxylic acids having 6 to 36 carbon atoms, particularly adipic acid, are preferred for the reasons described below. In a copolymerized polyester containing an ester unit derived from butylene glycol and an aliphatic dibasic acid, a free terminal carboxyl group having a long chain length and a high degree of freedom is present, and this contains Ge, S contained in the polyester.
It also provides the additional advantage that ionic cross-linking occurs through catalytic metals such as b and Ti, leading to increased melt tension.

The diol component is preferably composed of only butylene glycol. However, as long as the essence of the present invention is not impaired, diol components other than butylene glycol include ethylene glycol, propylene glycol and
It may contain one or more of diethylene glycol, 1,6-hexylene glycol, cyclohexane dimethanol, and an ethylene oxide adduct of bisphenol A.

This copolymerized polyester has an aromatic ester unit (a) and an aliphatic ester unit (b) as 85:
It is also important to include a molar ratio of 15 to 50:50,
When the content of the aliphatic ester unit is less than the above range, the improvement of impact resistance (dent resistance) is insufficient. On the other hand, when the content exceeds the above range, heat resistance of the coating, workability,
The barrier properties against corrosive components and the like are reduced.

The glass transition point (T
g) having a melting point (Tm) of 180 to 220 ° C. is preferred.

The copolyester used should have at least a molecular weight sufficient to form a film;
In the form of a blend, it gives the intrinsic viscosity described below. The upper limit of the intrinsic viscosity is preferably 1.5 or less.

In the intermediate layer used in the present invention, the ethylene terephthalate-based or ethylene naphthalate-based polyester (i) and the specific copolymerized polyester (ii) are (i) :( ii) = 70: 30 to 10:90. A polyester blend containing a weight ratio of 60:40 to 10:90 is used.

In the mixing or kneading operation, after dry mixing is performed using a blender or a Henschel mixer, melt kneading is performed using various kneaders or a single- or twin-screw extruder-type melt-kneading apparatus or a kneading apparatus for an injection machine. It can be carried out.

(C) Polyester composite film: The polyester composite film used in the present invention comprises a laminate of the above-mentioned ethylene terephthalate-based or ethylene naphthalate-based polyester surface layer and underlayer and the above-mentioned blended intermediate layer. Become. The middle layer is 90
It is preferably in the range of from 50 to 50% by weight, especially from 85 to 50% by weight. In the present invention, it is also a remarkable advantage that the film forming operation and the laminating operation can be performed smoothly while using the intermediate layer resin in such a large amount.

The thickness of the composite polyester film used in the present invention is 2 to 100 μm, especially 5 to 100 μm.
The range of from 50 μm to 50 μm is good in terms of metal protection effect and workability. In general, the blend layer and the ethylene terephthalate-based or ethylene naphthalate-based polyester layer have a thickness ratio of 15: 2 to 1: 1.

The composite film is produced by using an extruder for ethylene terephthalate-based or ethylene naphthalate-based polyester described above and an extruder for the blend described above, and extruding through a two-type three-layer die having branch channels. This is performed by casting.

The polyester film should generally be biaxially oriented. The degree of biaxial orientation can also be confirmed by X-ray diffraction, polarized fluorescence, birefringence, density gradient tube method, and the like.

Of course, this polyester film has
Compounding agents for films known per se, for example, anti-blocking agents such as amorphous silica, titanium dioxide (titanium white)
And various kinds of antistatic agents, lubricants and the like can be blended according to a known formulation.

Although not generally required, when an adhesive primer is used, it is generally desirable to subject the surface of the biaxially stretched polyester film to a corona discharge treatment in order to increase the adhesion to the adhesive primer to the film. .
The degree of the corona discharge treatment is such that the wetting tension is 44 dyne.
/ Cm or more.

In addition, the film may be subjected to a known surface treatment for improving adhesion such as plasma treatment or flame treatment or a coating treatment for improving adhesion of urethane resin or modified polyester resin. .

[Metal Plate] In the present invention, various surface-treated steel plates and light metal plates such as aluminum are used as the metal plate.

As the surface-treated steel sheet, a cold-rolled steel sheet is annealed and then subjected to secondary cold rolling, and is subjected to one or more kinds of surface treatments such as zinc plating, tin plating, nickel plating, electrolytic chromic acid treatment, and chromic acid treatment. Can be used.
An example of a suitable surface-treated steel sheet is an electrolytic chromic acid-treated steel sheet, particularly provided with a chromium metal layer of 10 to 200 mg / m ² and a chromium oxide layer of 1 to 50 mg / m ² (in terms of chromium metal). This is excellent in the combination of coating film adhesion and corrosion resistance. Another example of a surface-treated steel plate is a hard tin plate having a tin plating amount of 0.5 to 11.2 g / m ² . This tin plate is desirably subjected to chromic acid treatment or chromic acid-phosphoric acid treatment so that the amount of chromium is 1 to 30 mg / m ^{2 in} terms of metal chromium.

As still another example, an aluminum-coated steel sheet subjected to aluminum plating, aluminum pressure welding, or the like is used.

As the light metal plate, an aluminum alloy plate is used in addition to a so-called aluminum plate. An aluminum alloy plate excellent in corrosion resistance and workability has a Mn: 0.
2 to 1.5% by weight, Mg: 0.8 to 5% by weight, Z
n: 0.25 to 0.3% by weight, Cu: 0.15 to 0.25% by weight, with the balance being Al. It is desirable that these light metal plates have also been subjected to a chromic acid treatment or a chromic / phosphoric acid treatment such that the chromium amount becomes 20 to 300 mg / m ^{2 in} terms of chromium metal.

The thickness of the metal plate, that is, the thickness of the bottom of the can (tB)
) Varies depending on the type of metal, the purpose or the size of the container, but generally preferably has a thickness of 0.10 to 0.50 mm. Among them, in the case of a surface-treated steel sheet, 0.10 to 0. It is preferable to have a thickness of 0.30 mm, and in the case of a light metal plate, a thickness of 0.15 to 0.40 mm.

[Laminated Plate and Method for Producing the Same] The polyester-metal laminated plate used in the present invention can be produced by thermally bonding a biaxially stretched polyester film to a metal. At this time, it is preferable that at least a part of the biaxial molecular orientation remains in the polyester layer.

Referring to FIG. 7 for explaining a method for producing a polyester-metal laminate, a metal plate 20 is heated by a heating roll 21 to a temperature (Y ₁ ) higher than the melting point (Tm) of the polyester to be used. Supply in between. On the other hand, the polyester composite film 23
It is unwound from the supply roll 24 and the laminate roll 2
It is supplied in a positional relationship where the metal plate 20 is sandwiched between the metal plates 2 and 22. The laminating rolls 22 and 22 are maintained at a slightly lower temperature (Y ₂ ) than the heating roll 21, and heat-bond a polyester film to both surfaces of the metal plate 20. Below the laminating rolls 22, a water tank containing cooling water 26 for rapidly cooling the laminate 25 to be formed is provided, and a guide roller 27 for guiding the laminate into the water tank is arranged. A gap 28 having a predetermined interval is formed between the laminating rolls 22 and 22 and the cooling water 26, and a heat retaining mechanism 29 is provided in the gap 28 to maintain the temperature in a predetermined temperature range (Y ₃ ) and promote adhesion. You can make it.

The heating temperature (Y ₁ ) of the metal plate is generally (T
m−50) ° C. to (Tm + 100) ° C., especially (Tm−5)
0) ° C to (Tm + 50) ° C, while the temperature Y ₂ of the laminating roll 22 is (Y ₁ -300)
° C. to (Y ₁ -10) ℃, are suitable especially (Y ₁ -250) of ° C. to (Y ₁ -50) ℃ range. The laminate after passing through laminating rolls, it is effective to heat insulation in insulation zone, the holding temperature (Y ₃₎ is the temperature Y ₂ of laminating rolls with respect, (Y ₂ -50) ° C. to (Y ₂ +5
0) The range of ° C is appropriate. The temperature Y retention time to ₃ from 0.1 to 10 seconds, it is suitable especially 0.1 to 3 seconds.

The adhesive primer optionally provided between the polyester film and the metal material exhibits excellent adhesiveness to both the metal material and the film. A typical primer paint excellent in adhesion and corrosion resistance is a phenol epoxy paint composed of a resol type phenol aldehyde resin derived from various phenols and formaldehyde, and a bisphenol type epoxy resin, Particularly, a phenol resin and an epoxy resin are mixed in a ratio of 50: 5.
0 to 5:95 weight ratio, especially 40:60 to 10:90
Is a paint contained in a weight ratio of

The adhesive primer layer is generally preferably provided with a thickness of 0.01 to 10 μm. The adhesive primer layer may be provided in advance on a metal material or may be provided in advance on a polyester film.

[Seamless Can and Manufacturing Method Thereof] In FIG. 8 showing an example of the seamless can of the present invention, the seamless can 11 is made of the polyester-metal laminate 1 described above.
Formed by bending and stretching by drawing or redrawing or further ironing, and is composed of a bottom portion 10 and a side wall portion 12. A neck portion 13 is provided on the upper end of the side wall portion 12 if desired.
The flange portion 14 is formed through the opening. This can 11
In this case, the side wall portion 12 is thinner than the bottom portion 10 by bending or stretching or further ironing so as to have a thickness of 30 to 90% of the original thickness of the laminate.

The seamless can of the present invention is obtained by drawing and deep-drawing the above-mentioned polyester-metal laminate into a bottomed cup between a punch and a die, bending and elongating in the deep-drawing stage and ironing the cup side wall. It is manufactured by thinning. That is, the deformation for thinning is performed by a combination of the deformation (bending and elongation) due to the load in the can axis direction (height direction) and the deformation (ironing) due to the load in the can thickness direction, and in this order.

The draw-ironing of the laminate is performed by the following means. That is, as shown in FIG. 9, a front drawing cup 30 formed from a coated metal plate is held by an annular holding member 31 inserted into the cup and a redrawing-ironing die 32 located thereunder. . Coaxially with the holding member 31 and the redrawing-ironing die 32,
A re-drawing-ironing punch 33 is provided so as to be able to get in and out of the inside. The redrawing-ironing punch 33 and the redrawing-ironing die 32 are relatively moved so as to bite each other.

The redrawing-ironing die 32 has a flat portion 34 at an upper portion, and a working corner portion 35 having a small radius of curvature on the periphery of the flat portion, and the diameter increases downward toward the periphery connected to the working corner portion. Tapered approach portion 36
Following the approach portion, a cylindrical ironing land portion (ironing portion) 38 is provided via a small curvature portion 37. Below the land portion 38, a reverse tapered relief 3
9 are provided.

The side wall of the front drawing cup 30 is bent perpendicularly inward from the outer peripheral surface 40 of the annular holding member 31 through the curvature corner portion 41 to re-draw with the annular bottom surface 42 of the annular holding member 31. It passes through a portion defined by the flat portion 34 of the die 32 and is bent substantially vertically in the axial direction by the working corner portion 35 of the redraw die 32, and is formed into a deep drawn cup having a smaller diameter than the front drawn cup 30. At this time, the portion of the working corner 35 opposite to the side in contact with the corner 35 is elongated by bending deformation, while the portion in contact with the working corner 35 is returned after leaving the working corner. It is stretched by deformation, whereby the side wall is thinned by bending and stretching.

The side wall part thinned by bending and stretching is
Its outer surface comes into contact with the approach portion 36 having a small taper angle whose diameter gradually increases, and its inner surface is guided to the ironing portion 38 in a free state. The process of passing the side wall portion through the approach portion is a stage prior to the subsequent ironing process, and stabilizes the laminate after bending and stretching, and slightly reduces the diameter of the side wall portion to prepare for ironing. That is, the laminate immediately after bending and stretching has the effect of vibration due to bending and stretching, distortion remains inside the film, it is still in an unstable state, and if it is immediately ironed, Although smooth and hard ironing cannot be performed, the outer surface of the side wall portion is brought into contact with the approach portion 36 to reduce its diameter, and the inner surface is kept free to prevent the influence of vibration, thereby preventing the influence of vibration. In addition, the non-homogeneous distortion can be reduced, and smooth ironing can be performed.

The side wall passing through the approach portion 36 is introduced into the gap between the ironing land portion (ironing portion) 38 and the redrawing-ironing punch 33, and is rolled to a thickness regulated by the gap (C1). You. The thickness C1 of the final side wall is determined to be 30 to 90% of the original thickness (t) of the laminate. The small curvature portion 37 on the ironing portion introduction side smoothly introduces the laminated body into the ironing portion 38 while effectively fixing the ironing start point, and has a reverse tapered shape below the land portion 38. The relief 39 prevents an excessive increase in the processing force.

The re-drawing—the radius of curvature Rd of the curvature corner portion 35 of the ironing die 32 is 2.9 times or less, particularly 2.5 times or less the thickness (t) of the laminated plate in order to effectively perform bending and elongation. However, if this radius of curvature is too small, the laminate will break,
It should be at least 1 times, especially at least 1.2 times, the thickness (t) of the laminate.

The approach angle (１ ／ of the taper angle) α of the tapered approach portion 36 should be 1 to 10 °, especially 1.5 to 8 °. When the angle of the approach portion is smaller than the above range, relaxation of the orientation of the polyester film layer and stabilization before ironing become insufficient, and when the angle of the approach portion is larger than the above range, the bending and elongation are uneven (return). Deformation is insufficient)
In any case, smooth and hard ironing becomes difficult without cracking or peeling of the film.

The radius of curvature Ri of the small curvature portion 37 should be equal to or less than 1.0 of the thickness (t) of the laminate plate in order to effectively fix the ironing start point. If this radius of curvature is too large, ironing cannot be performed effectively.

Although the ironing land 38, the re-drawing-ironing punch 33 and the clearance are in the above-mentioned ranges, the land length L is generally preferably 0.5 to 30 mm. If the length is larger than the above range, the working force tends to be excessively large. On the other hand, if the length is smaller than the above range, the return after ironing is large, which may be undesirable.

In producing the seamless can of the present invention, the polyester layer on the surface imparts sufficient lubricating performance. However, in order to further enhance lubricity, a small amount of a lubricant such as various oils or waxes is used. It can be applied and formed by dry lubrication. Of course, an aqueous coolant containing a lubricant (of course, also serving as cooling) can be used, but should be avoided in terms of simplicity of operation.

The temperature at the time of redrawing and ironing (the temperature immediately after the completion of ironing) is higher than the glass transition point (Tg) of the polyester.
The temperature is preferably from (g + 10) ° C. to lower than the melting point. For this reason, it is preferable to heat the tool or conversely cool it.

Next, the drawn container can be subjected to at least one stage of heat treatment. This heat treatment has various purposes, and mainly includes removing residual strain of a film generated by processing, volatilizing a lubricant used for processing from a surface, and drying and curing a printing ink printed on the surface. Is the purpose. For this heat treatment, a heating device known per se, such as an infrared heater, a hot air circulation furnace, and an induction heating device, can be used. In addition, this heat treatment may be performed in one stage, or may be performed in two or more stages. The heat treatment temperature is suitably in the range of 180 to 240 ° C. The heat treatment time is generally 1 to 1
It is on the order of 0 minutes.

The container after the heat treatment may be cooled rapidly or may be left to cool. That is, in the case of a film or a laminate, the quenching operation is easy, but in the case of a container, the quenching operation in an industrial sense is difficult because it is three-dimensional and has a large heat capacity due to metal. In the present invention, even without a quenching operation, crystal growth is suppressed, and excellent combination characteristics can be obtained. Of course, if desired, it is optional to employ a rapid cooling means such as blowing cold air or spraying cooling water.

The obtained can is subjected to one-stage or multi-stage neck-in processing, if necessary, and flanged to obtain a can for winding. Prior to neck-in processing, bead processing or circumferential polyhedral wall processing described in Japanese Patent Publication No. 7-5128 can be performed.

[0076]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the following examples. Various measured values are
It was determined by the following measurement method.

(1) Measurement of dynamic viscoelasticity (vibron measurement) As a film for measurement, a laminate plate was cut into a 6 cm square, immersed in an 18% aqueous chlorine solution at room temperature, and after dissolving the metal plate, the film was washed. Obtained by vacuum drying for 24 hours. The film was cut out into a size of 50 mm in length and 4 mm in width to obtain a measurement sample. The dynamic viscoelasticity measurement was performed under the following conditions. Dynamic viscoelasticity measurement device: manufactured by Toyo Baldwin Co., Ltd.
DDV-II type Frequency: 110 HZ, heating rate: 2 ° C./min, measuring interval: 2 ° C., measuring temperature range: −150 ° C. to 180 ° C. The obtained peaks are T ₁ , T ₂ , and T ₃ from the high temperature side. did.

(2) Melting point A film was isolated from a laminate plate in the same manner as in the above-mentioned method (1), and the washed and dried film was used as a sample for measurement. The measurement conditions are shown below. DSC device: PerkinElmer DSC7 type Heating rate: 20 ° C./min Weighing: 5 to 10 mg

(3) IV (Intrinsic Viscosity) A film was isolated from the laminate by the method described above, and 200 mg
The mixture was dissolved in a phenol / 1,1,2,2-tetrachloroethane mixed solution (weight ratio: 1: 1) at 110 ° C., and the specific viscosity was measured at 30 ° C. using an Ubbelohde viscometer. The intrinsic viscosity was determined by the following equation. [Η] = [｛− 1+ (1 + 4K′ηsp) ^1/2 ｝ / 2K ′
C] (dl / g) K ′: Constant of Haggins (= 0.33) C: Concentration (g / 100 ml) ηsp: Specific viscosity [= (fall time of solution−fall time of solvent) / fall time of solvent ]

(4) Residual orientation The residual orientation of the laminate was measured using an X-ray diffractometer under the following conditions. Apparatus: RAD-B goniometer manufactured by Rigaku Denki Co., Ltd. Light source: CuKα (1.542 angstroms) Tube voltage: 30 KV, tube current: 100 mA By the reflection method under the above conditions, the diffraction angle 2θ is between 20 and 30 °. By operation, the X-ray diffraction intensity on a diffraction plane having a plane spacing of about 0.34 nm (2θ is around 26 °) parallel to the polyester film surface was determined. From the X-ray diffraction intensity peak I _{0 of the} raw film and the X-ray diffraction intensity peak I of the laminate film, the residual orientation was determined by the following equation. Residual orientation (%) = I / I ₀ × 100

(5) Corrosion test 100 pieces of sports drinks were hot-filled at 90 ° C., allowed to cool, stored at 37 ° C. for 1 week, cooled to 5 ° C., and then the can shaft was set vertically. An impact was given by dropping from a height of 50 cm at an angle of 15 ° to the direction. Then 3
A storage test was performed at a temperature of 7 ° C., and the can was opened one year later, and the corrosion state of the neck processed portion on the inner surface side was observed. Corrosion was also observed for the part that was impacted by the drop.

Experimental Example 1 The following TFS steel plate was used as a metal plate. TFS steel sheet: 0.180 mm thick, temper DR-6, chromium metal content 110 mg / m ² , chromium hydrated oxide content 15
mg / m ² A polyester film of the following (1) on one side of this metal plate,
On the other side, a polyester film of (2) below,
50 ° C, laminating roll temperature 150 ° C, passing speed 40
Both sides were simultaneously heat-laminated at m / min and immediately cooled with water to obtain a laminated metal plate. Polyester film (1) (outer side of the can): A white resin obtained by blending 20% by weight of titanium oxide (pigment) with a polyester resin consisting of 12% by mole of isophthalic acid, 88% by mole of terephthalic acid and 100% by mole of ethylene glycol. A biaxially stretched film (thickness: 13 μm) obtained by stretching a polymer polyester resin under conditions of 3.0 times length and 3.0 times width. Polyester film (2) (inner side of can): Copolymer polyester (a) of terephthalic acid / isophthalic acid (molar ratio: 88:12) and ethylene glycol in the surface layer and lower layer
Terephthalic acid / isophthalic acid (molar ratio 9
4: 6) and a copolymerized polyester (b) of ethylene glycol with terephthalic acid / adipic acid (molar ratio: 80: 6).
(A) / (d) / (b) A resin (d) obtained by blending 20) with a copolymerized polyester (c) composed of 1,4-butanediol at a weight ratio of (b) :( c) = 30: 70. Co-extrusion was carried out in the configuration of a), and the film was stretched under the conditions of 3.0 times length × 3.0 times width and heat-set to obtain a biaxially stretched film. The thickness composition ratio is shown in Table 1.

A wax-based lubricant was applied to the coated metal plate obtained above, and a disk having a diameter of 166 mm was punched out so that the polyester film (1) side was the outer surface of the can to obtain a shallow drawn cup. Next, the shallow drawn cup was redrawn and ironed to obtain a deep drawn and ironed cup. The characteristics of this deep drawing cup were as follows. Cup diameter: 60 mm Cup height: 128 mm 65% of the thickness of the can wall relative to the base plate thickness

The deep drawn ironing cup was subjected to doming molding according to a conventional method, and heat treatment was performed at 215 ° C., and then the cup was allowed to cool, followed by trimming of the opening edge, curved surface printing and baking drying, and necking. Processing and flange processing were performed to obtain a seamless can for a capacity of 350 ml.

Next, the sports drink was hot-filled and then subjected to a corrosion test. The results are shown in Table 1. Good results were obtained for both the corrosion resistance of the neck part and the corrosion resistance of the impact part. The details of the resin composition are shown in Table 2.

EXPERIMENTAL EXAMPLE 2 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one side (the inner side of the can) of a TFS steel sheet was prepared by using the following Table 1.
The laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched laminated film shown in (1) was used (however, the plate temperature during thermal lamination was 255 ° C.). A can was made and a corrosion test was performed in the same manner as in Experimental Example 1. The results are shown in Table 1. Good results were obtained for both the corrosion resistance of the neck part and the corrosion resistance of the impact part. The details of the resin composition are shown in Table 2.

Experimental Example 3 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one surface (the inner surface side of the can) of the TFS steel sheet was prepared as shown in Table 1.
A laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched laminated film shown in (1) was used (however, the plate temperature during thermal lamination was 250 ° C.). A can was made and a corrosion test was performed in the same manner as in Experimental Example 1. The results are shown in Table 1. Good results were obtained for both the corrosion resistance of the neck part and the corrosion resistance of the impact part. The details of the resin composition are shown in Table 2.

Experimental Example 4 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one side (the inner side of the can) of the TFS steel sheet was prepared as shown in Table 1.
A laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched laminated film shown in (1) was used (however, the plate temperature during thermal lamination was 275 ° C.). 230 ° C heat treatment temperature
A can was made in the same manner as in Experimental Example 1 except that the test was performed, and a corrosion test was performed. The results are shown in Table 1. Good results were obtained for both the corrosion resistance of the neck part and the corrosion resistance of the impact part. The details of the resin composition are shown in Table 2.

EXPERIMENTAL EXAMPLE 5 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one side (the inner side of the can) of the TFS steel sheet was prepared as shown in Table 1.
The laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched laminated film shown in (1) was used (however, the plate temperature during thermal lamination was 245 ° C.). Cans were made in the same manner as in Experimental Example 1,
A corrosion test was performed. The results are shown in Table 1. The corrosion resistance of the neck portion was good, and slight corrosion was observed at the impact portion, but it was judged that it was within the practical range. The details of the resin composition are shown in Table 2.

EXPERIMENTAL EXAMPLE 6 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one side (the inner side of the can) of the TFS steel sheet was prepared as shown in Table 1.
A laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched laminated film shown in (1) was used (however, the plate temperature during thermal lamination was 270 ° C.). Heat treatment temperature of can 225 ° C
A can was made in the same manner as in Experimental Example 1 except that the test was performed, and a corrosion test was performed. The results are shown in Table 1. The corrosion resistance of the impact part was good. The neck portion was slightly corroded under the film, but was concealed by the white film, and was judged to be within the practical range. The details of the resin composition are shown in Table 2.

Experimental Example 7 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one side (the inner side of the can) of the TFS steel sheet was prepared as shown in Table 1.
The laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched single-layer film shown in (1) was used (however, the plate temperature during thermal lamination was 250 ° C.). Cans were made in the same manner as in Experimental Example 1,
A corrosion test was performed. The results are shown in Table 1. Film cracks were observed in the neck portion and the impact portion, and corrosion occurred, and it was judged that the film was not practically applicable. The details of the resin composition are shown in Table 2.

Experimental Example 8 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one surface (the inner surface side of the can) of the TFS steel sheet was prepared as shown in Table 1.
A laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched laminated film shown in (1) was used (however, the plate temperature during thermal lamination was 260 ° C.). Heat treatment temperature of can 225 ° C
A can was made in the same manner as in Experimental Example 1 except that the test was performed, and a corrosion test was performed. The results are shown in Table 1. Film cracks were observed in the neck portion and the impact portion, and corrosion occurred, and it was judged that the film was not practically applicable. The details of the resin composition are shown in Table 2.

EXPERIMENTAL EXAMPLE 9 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one side (the inner side of the can) of the TFS steel sheet was prepared as shown in Table 1.
A laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched laminated film shown in (1) was used (however, the plate temperature during thermal lamination was 250 ° C.). Cans were made in the same manner as in Experimental Example 1,
A corrosion test was performed. The results are shown in Table 1. Corrosion was not observed in the impact portion, but film cracking was observed in the neck portion and corrosion occurred, and it was judged that it was not practically applicable. The details of the resin composition are shown in Table 2.

Experimental Example 10 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one side (the inner side of the can) of the TFS steel sheet was prepared as shown in Table 1.
A laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched laminated film shown in (1) was used (however, the plate temperature during thermal lamination was 250 ° C.). Cans were made in the same manner as in Experimental Example 1,
A corrosion test was performed. The results are shown in Table 1. Film cracks were observed in the neck portion and the impact portion, and corrosion occurred, and it was judged that the film was not practically applicable. The details of the resin composition are shown in Table 2.

EXPERIMENTAL EXAMPLE 11 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one side (the inner side of the can) of the TFS steel sheet was prepared by using
A laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched laminated film shown in (1) was used (however, the plate temperature during thermal lamination was 250 ° C.). Cans were made in the same manner as in Experimental Example 1,
A corrosion test was performed. The results are shown in Table 1. Film cracks were observed in the neck portion and the impact portion, and corrosion occurred, and it was judged that the film was not practically applicable. The details of the resin composition are shown in Table 2.

Experimental Example 12 In Experimental Example 1, the biaxially stretched polyester film (2) provided on one side (inner side of the can) of the TFS steel sheet was prepared by using the same method as in Table 1.
A laminated metal plate was obtained in the same manner as in Experimental Example 1 except that the biaxially stretched laminated film shown in (1) was used (however, the plate temperature during thermal lamination was 250 ° C.). Cans were made in the same manner as in Experimental Example 1,
A corrosion test was performed. The results are shown in Table 1. Film cracks were observed in the neck portion and the impact portion, and corrosion occurred, and it was judged that the film was not practically applicable. The details of the resin composition are shown in Table 2.

[0097]

[Table 1]

[0098]

[Table 2]

[0099]

According to the present invention, in a laminate comprising a metal substrate and a resin layer mainly composed of polyester, the polyester has a loss elastic modulus satisfying all of the above formulas (I) to (IV). By using the composite polyester film, it was possible to provide a metal-polyester laminate excellent in the combination of impact resistance (particularly, dent resistance), workability, and content resistance. Seamless cans made from the above laminates, despite advanced drawing or ironing and heat treatment during or after can making,
Embrittlement due to crystallization is suppressed, and a combination of excellent dent resistance, workability, and content resistance is maintained.

[Brief description of the drawings]

FIG. 1 shows a polyester metal laminate of Experimental Example 7.
It is the graph which performed the dynamic viscoelasticity test of the polyester layer, and plotted the relationship between temperature and loss elastic modulus.

FIG. 2 shows a polyester metal laminate of Experimental Example 8.
It is the graph which performed the dynamic viscoelasticity test of the polyester layer, and plotted the relationship between temperature and loss elastic modulus.

FIG. 3 shows a polyester metal laminate of Experimental Example 9.
It is the graph which performed the dynamic viscoelasticity test of the polyester layer, and plotted the relationship between temperature and loss elastic modulus.

FIG. 4 is a graph in which a dynamic viscoelasticity test of a polyester layer is performed on the polyester metal laminate of Experimental Example 1 (the present invention), and the relationship between temperature and loss elastic modulus is plotted.

FIG. 5 is a cross-sectional view showing an example of a cross-sectional structure of the laminate of the present invention.

FIG. 6 is a cross-sectional view showing another example of the cross-sectional structure of the laminate of the present invention.

FIG. 7 is an explanatory diagram for explaining a method for producing a polyester-metal laminate.

FIG. 8 is a sectional view showing an example of the seamless can of the present invention.

FIG. 9 is a cross-sectional view showing a main part of a drawing-ironing means of the polyester-metal laminate of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminated body 2 Metal substrate 3 Composite polyester layer 4 Outer surface coating 5 Surface layer 6 Intermediate layer 7 Base layer 8 Adhesive primer layer 10 Bottom part 11 Seamless can 12 Side wall part 13 Neck part 14 Flange part 20 Metal plate 21 Heating roll 22, Reference Signs List 22 laminating roll 23 polyester composite film 24 supply roll 25 laminating plate 26 cooling water 27 guide roller 28 gap 29 heat retaining mechanism 30 front drawing cup 31 annular holding member 32 redrawing-ironing die 33 redrawing-ironing punch 34 flat part 35 small action Corner portion 36 approach portion 37 small curvature portion 38 land portion 39 reverse tapered relief 40 outer peripheral surface 41 curvature corner portion 42 annular bottom surface

Claims (6)

[Claims] 1. A laminate comprising a metal substrate and a resin layer mainly composed of polyester, wherein the polyester has the following formula: T ₁ ≧ 70 (I) 50 ≧ T ₂ ≧ 10 (II) T ₃ ≦ −60 {(III) and T ₁ −T ₂ ≧ 25} (IV) where T ₁ , T ₃ and T ₂ are
A laminate comprising a composite polyester film having a loss elastic modulus that satisfies a high temperature peak temperature, a low temperature peak temperature, and an intermediate peak temperature. 2. The composite polyester film according to (1),
A surface layer composed of a polyester mainly composed of ethylene terephthalate or ethylene naphthalate, (2) a copolymerized polyester or polyester composition derived from terephthalic acid or naphthalenedicarboxylic acid and an aliphatic dibasic acid and ethylene glycol and butylene glycol 2. The laminate according to claim 1, wherein the laminate is a laminated film comprising an intermediate layer composed of: and (3) a base layer composed of polyester mainly composed of ethylene terephthalate or ethylene naphthalate. 3. The intermediate layer comprises: (i) a polyester mainly composed of ethylene terephthalate units or ethylene naphthalate; and (ii) (a) an ester unit derived from butylene glycol and an aromatic dibasic acid; And (i) :( ii) = 70: 30 to 1) a copolymerized polyester containing ester units derived from butylene glycol and an aliphatic dibasic acid in a molar ratio of 85:15 to 50:50.
3. The laminate according to claim 2, wherein the laminate is formed from a blend containing a weight ratio of 0:90. 4. The laminate according to claim 2, wherein the intermediate layer accounts for 90 to 50% by weight of the composite polyester film. 5. The laminate according to claim 1, wherein the composite film is a biaxially stretched film. 6. A seamless container obtained by drawing or laminating the laminate according to any one of claims 1 to 5.