JP3407478B2 - Polymer-coated metal laminate - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to polymer coated metal laminates. More specifically, the present invention relates to a polymer-coated metal laminate having excellent moldability, impact resistance and taste characteristics, which is suitable for a metal can manufactured by a molding process.

[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, there is a method in which a polymer is extrusion-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 the metal can. When a metal can is manufactured by drawing or ironing a polymer laminated metal plate, the polymer laminated metal plate is required to have the following characteristics.

(1) It has excellent moldability and does not cause defects such as pinholes after molding.

(2) The polymer should not be peeled from the metal plate, or cracks or pinholes should not be generated by the impact on the metal can.

(3) The scent component of the contents of the can is adsorbed on the polymer, and the flavor of the contents is not impaired by the odor of the components eluted from the polymer (hereinafter referred to as taste characteristics).

Many proposals have been made to solve these requirements. For example, Japanese Patent Application Laid-Open No. 51-17988 discloses a metal body obtained by extrusion laminating a polyethylene terephthalate polymer having a crystallinity of 20% or less, and a special feature. Kai 51-1
No. 48755 discloses a metal body obtained by extrusion laminating a polymethylene terephthalate polymer on a metal body heated to 200 to 350 ° C., and Japanese Patent Publication No. 2-9935 discloses a metal body.
A metal body or the like in which a multilayer polyester is extrusion-laminated on a metal body heated to less than 0 ° C. is disclosed. However, these proposals are not ones that can comprehensively satisfy the various required characteristics described above, and cannot be said to be at a sufficiently satisfactory level particularly in terms of achieving both impact resistance and taste characteristics. It was

[0008]

The object of the present invention is to eliminate the above-mentioned problems of the prior art, and is excellent in moldability, impact resistance and taste characteristics, and particularly to achieve both impact resistance and taste characteristics at the same time. An object of the present invention is to provide a polymer-coated metal laminate suitable for a metal can manufactured by excellent molding.

[0009]

The above-mentioned object of the present invention has a melting point of 140 to 245 ° C. and a polyester component.
Polyester A and thermoplastic elastomer weight ratio of 70 mol% or more is ethylene terephthalate and / or ethylene isophthalate 70:30 to 98: formulated at 2 comprising (I) layer was coated by extrusion lamination It can be achieved by a polymer-coated metal laminate characterized in that

According to the present invention, a polyester having a specific melting point is mixed with an appropriate amount of a thermoplastic elastomer, extrusion-laminated on a metal, and then molded and formed into a can. It was found that good impact resistance can be obtained even when subjected to a lot of heat history such as retort treatment. The effect is extremely large as compared with the prior art in that not only the impact resistance and taste characteristics are compatible, but also the impact resistance can be dramatically improved.

The polyester having ethylene terephthalate and / or ethylene isophthalate as a main constituent in the present invention means 70 mol% of the polyester component.
The above is a polyester which is ethylene terephthalate and / or ethylene isophthalate, preferably 8
A polyester in which 0 mol% or more is ethylene terephthalate and / or ethylene isophthalate. Here, the polyester is a polymer composed of a dicarboxylic acid component and a glycol component, a dicarboxylic acid component other than the above,
For example, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenoxyethane dicarboxylic acid, 5-sodium sulfoisophthalic acid, aromatic dicarboxylic acid such as phthalic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid , A maleic acid, an aliphatic dicarboxylic acid such as fumaric acid, an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid, an oxycarboxylic acid such as p-oxybenzoic acid, etc. Good. On the other hand, as the glycol component, other than ethylene glycol, propanediol, butanediol, pentanediol,
Copolymerization of hexanediol, aliphatic glycol such as neopentyl glycol, alicyclic glycol such as cyclohexanedimethanol, aromatic glycol such as bisphenol A and bisphenol S, polyoxyethylene glycol such as diethylene glycol and polyethylene glycol Of the glycol components, butanediol is often preferable from the viewpoint of improving impact resistance. 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 A used in the present invention has a melting point of 140 to 245 ° C. in heat resistance,
It is necessary from the viewpoint of sufficient adhesiveness to the metal plate and from the viewpoint of suppressing decomposition of the thermoplastic elastomer when mixed with the thermoplastic elastomer. Preferred are copolymerized polyesters such as isophthalic acid copolymerized polyethylene terephthalate and butanediol / isophthalic acid copolymerized polyethylene terephthalate, and polyesters obtained by copolymerizing the polyester with polyoxyethylene glycol such as diethylene glycol and polyethylene glycol. In particular, isophthalic acid copolymerized polyethylene terephthalate and polyester obtained by copolymerizing the polyester with polyoxyethylene glycol such as diethylene glycol and polyethylene glycol are preferably used.

The thermoplastic elastomer in the present invention is a rubber component (soft segment) that is plasticized at high temperature and can be molded in the same manner as plastics, exhibits the properties of a rubber elastic body at normal temperature, and exerts entropy elasticity. It is a polymer that consists of constraining components (hard segments) that flow at high temperatures, but are necessary to create a mechanism that prevents plastic deformation at room temperature. Tensile elastic modulus is 1 to 500
0 kgf / cm ² , hardness of 10 to 90 JIS A
Are preferred. The thermoplastic elastomer in the present invention is not particularly limited, but polystyrene elastomers (hard segment: polystyrene, soft segment: polybutadiene, polyisoprene, hydrogenated polybutadiene, ethylene-propylene copolymer rubber, etc.), polyolefin elastomer (hard segment: polyethylene). Or polypropylene, soft segment: ethylene-propylene copolymer rubber, polybutadiene, polyisoprene, hydrogenated polybutadiene, etc.), polyester elastomer (hard segment: polyester, soft segment: polyether or polyester), polyamide elastomer (hard segment:
Polyamide, soft segment: polyether or polyester), and other examples include those in which the hard segment is syndio-1,2-polybutadiene and the soft segment is atactic-1,2-polybutadiene. Further, a known functional group such as a hydroxyl group, a carboxyl group, an epoxy group, an amide group and a maleic anhydride component and a functional group-forming component may be partially introduced into the thermoplastic elastomer, but most of the functional groups are metal-chlorided. This is not preferable because it deteriorates the taste characteristics. Of these, polystyrene-based elastomers and polyester-based elastomers are preferable for improving impact resistance and taste characteristics. Specifically, polystyrene-based such as SBS (styrene-butadiene-styrene copolymer), SEBS (styrene-ethylene / butylene-styrene copolymer), SIS (styrene-isoprene-styrene copolymer), SEP (styrene-ethylene / propylene copolymer). Elastomer, HYTREL (manufactured by Toray Dupont), ARN
ITEL (Akzo Chemie), Perprene (Toyobo), LOMOD (General Elec
A polyester-based elastomer such as Tric) can be preferably used, and particularly, SEBS is preferable because the impact resistance can be improved even when the addition amount is small and a good film for thermal lamination can be obtained without impairing the taste characteristics.

The thermoplastic elastomer is polyester A
From the viewpoint of melt extrudability, the melt index under a load of 2160 g at 210 ° C. is preferably 0.1 to 50 g / 10 minutes, more preferably 0.5 to 30 g / 10.
Min, more preferably 1 to 20 g / 10 min.

Further, it is preferable to add a known compatibilizing agent to the mixed layer of polyester A and the thermoplastic elastomer to improve the compatibility, because the impact resistance is further improved.

In the present invention, the polyester (A) and the thermoplastic elastomer are blended in a weight ratio of 70:30 to 98: 2 in order to achieve both good impact resistance and good taste characteristics, and the (I) layer is made of metal. It needs to be formed on the body. The weight ratio of polyester A to the thermoplastic elastomer is more preferably 70:30 to 95: 5, and more preferably 75:25 to 93: 7. Furthermore, components other than the polyester A and the thermoplastic elastomer may be mixed. As described above, by containing an appropriate amount of the thermoplastic elastomer, which is considered to be excellent in flexibility even at low temperature, in the polyester A, the impact resistance is greatly improved even after the heat history during can making.

Further, in the present invention, when the dispersion diameter ratio (= longitudinal average dispersion diameter / thickness direction average dispersion diameter) of the thermoplastic elastomer dispersed in polyester A is 2 to 100, impact resistance is particularly improved. I found a thing. further,
A dispersion diameter ratio of 4 to 50 is particularly preferable because the retort dent property is improved. Here, the dispersion diameter ratio of the thermoplastic elastomer is, for example, 0.1 to 1 in thickness obtained by cutting a polymer cross section.
An ultra-thin section of about μm was made and photographed with a transmission electron microscope at a magnification of about 5,000 to 20,000 (longitudinal direction: 25
cm × 10 in thickness direction 20 cm) is photographed, and the longitudinal diameter (xi), thickness direction diameter (yi), and ellipse equivalent area (Si) of each thermoplastic elastomer (i) dispersed in polyester A are measured. . Then, the average dispersion diameter in the longitudinal direction (xav) and the average dispersion diameter in the thickness direction (yav) were calculated for each direction using the following formulas, and the dispersion diameter ratio (= xav / yav) was obtained.

[0019]

[Equation 1]

[Equation 2] The method of adjusting the dispersion diameter ratio to 2 to 100 is not particularly limited, but a method of providing a mixing structure in the metering portion of the screw, for example, Dalmaged screw, unimelt screw, pin screw, BM screw, wave screw, HM screw, A method of increasing the kneading property by increasing the shearing force such as a DIS screw or a multi-screw pin screw, extrusion by a twin-screw extruder, and a screw dimension suitable for pre-kneading the screw of the twin-screw extruder (for example, a polymer to a certain length A method of setting a portion to be retained and kneading therewith a material having a highly kneading property such as a rotor) is used.

On the other hand, considering the scratch resistance in the can making process and the non-adsorption of the perfume component of the can contents, in addition to the layer (I),
It is preferable to laminate a (II) layer made of polyester B having ethylene terephthalate having a melting point of 220 to 260 ° C. as a main constituent. If the melting point is less than 220 ° C, the heat resistance of the can is insufficient, which is not preferable. Here, the polyester having ethylene terephthalate as a main constituent component means a polyester having 70 mol% or more, preferably 80 mol% or more ethylene terephthalate units.
In addition, a small amount of thermoplastic elastomer may be added with emphasis on impact resistance within a range that does not impair taste characteristics.

Further, polyester A and polyester B
The melting point difference is preferably 35 ° C or less, more preferably 3
It is preferable that the temperature is 0 ° C. or lower, and more preferably 25 ° C. or lower, because the difference in thermal expansion and contraction behavior between the (I) layer and the (II) layer becomes small during the heat history in the can making process, and the workability is improved.

In the present invention, the amount of carboxyl terminal groups of the polyester component is preferably 35 equivalents / ton or less from the viewpoints of the thermal stability and taste characteristics of the polymer forming the layer (I). More preferably, the carboxyl end group amount is 30 equivalents /
Below tons. Specifically, solid phase polymerization, a method of reducing the amount of carboxyl terminal groups to a predetermined amount with a known end-capping agent such as carbodiimide, oxazoline and the like can be preferably performed.

On the other hand, increasing the amount of carboxyl terminal groups in the surface layer portion of the (I) layer by surface treatment or the like is preferable for improving the adhesiveness.

The polyester in the present invention preferably has an amount of diethylene glycol component of 0.01 to 1.5% by weight, more preferably 0.01 to 1.0% by weight, and still more preferably 0.01 to 0.6% by weight. It is desirable to maintain good impact resistance even when subjected to a lot of heat history such as heat treatment in the can making process and retort treatment after can making. This is considered to improve the resistance to oxidative decomposition at 200 ° C. or higher.
~ 1 wt% may be added.

When the content of the diethylene glycol component is less than 0.01, the polymerization process becomes complicated and it is not preferable in terms of cost. When it exceeds 1.5% by weight, the polyester is deteriorated due to the heat history in the can making process. It tends to reduce impact resistance. Diethylene glycol is generally produced as a by-product during the production of polyester, but in order to reduce the amount, the polymerization time is shortened, a method of limiting the amount of an antimony compound, a germanium compound, etc. used as a polymerization catalyst, liquid phase polymerization. And a method of combining solid-state polymerization,
Examples thereof include a method of incorporating an alkali metal component, but the method is not particularly limited.

In order to improve the taste characteristics, the content of acetaldehyde in the polyester is preferably 30 p.
pm or less, further preferably 25 ppm or less, more preferably 20 ppm or less. If the content of acetaldehyde exceeds 30 ppm, the taste characteristics are poor. The method for controlling the content of acetaldehyde in the polyester to 30 pm or less is not particularly limited, but for example, in order to remove acetaldehyde generated by thermal decomposition when the polyester is produced by a polycondensation reaction or the like, the polyester may be used under reduced pressure or A method of heat-treating at a temperature not higher than the melting point of polyester in an inert gas atmosphere, preferably a method of solid-phase polymerizing polyester at a temperature not lower than 150 ° C. and not higher than the melting point under reduced pressure or in an inert gas atmosphere, vent-type extruder And a method of performing extrusion in a short time at a melting point of + 30 ° C. or less, more preferably at a melting point of + 25 ° C. or less.

In order to improve impact resistance and taste characteristics in the present invention, the intrinsic viscosity [η] of the polyester is preferably 0.7 or more, more preferably the intrinsic viscosity [η] is 0.75. Above, more preferably the intrinsic viscosity [η]
Is preferably 0.8 or more because the entanglement density of polymer molecular chains is increased, but impact resistance and taste characteristics can be further improved, which is preferable.

When the polymer-coated metal laminate of the present invention is used for beverages and food cans, the polyester preferably contains 1 to 500 ppm of a germanium element in terms of taste characteristics, more preferably 5 to 300 ppm, More preferably, it is 10 to 100 ppm. If the content of germanium element is less than 1 ppm, the effect of improving the taste characteristics is not sufficient, and if it exceeds 500 ppm, foreign matter is generated in the polyester to deteriorate the impact resistance and the taste characteristics. 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 of incorporating the germanium element into the polyester may be any conventionally known method and is not particularly limited, but usually, at any stage before the completion of the production of the polyester, a germanium compound may be added as a polymerization catalyst. preferable. As such a method, for example, a method of directly adding a powder of germanium compound, or Japanese Patent Publication No.
As described in JP-A-4-22234, a method of dissolving and adding a germanium compound in a glycol component which is a starting material of polyester can be mentioned. Examples of the germanium compound, germanium dioxide, germanium hydroxide containing crystal water, or germanium tetramethoxide, germanium tetraethoxide, germanium tetrabutoxide, germanium alkoxide compounds such as germanium ethylene glycoloxide, germanium phenolate, germanium β-naphtholate, etc. Examples thereof include phosphorus-containing germanium compounds such as germanium phenoxide compounds, germanium phosphate and germanium phosphite, and germanium acetate. Of these, germanium dioxide is preferable.

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 even more preferably 0.6% by weight or less. When the content of the oligomer in the copolyester exceeds 0.8% by weight, 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. The terephthalic acid component, isophthalic acid component and ethylene glycol are transesterified or esterified, and then germanium dioxide and a phosphorus compound are added, followed by polycondensation reaction at a high temperature and a reduced pressure until a constant diethylene glycol content is obtained, and a germanium element is added. A containing polymer is obtained.
Then, the obtained polymer is subjected to solid-phase polymerization reaction at a temperature below its melting point under reduced pressure or under an inert gas atmosphere,
Examples thereof include a method of reducing the content of acetoaldehyde and obtaining a predetermined intrinsic viscosity [η] and a carboxyl terminal group.

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.

In the present invention, the polyester A and the polyester B may differ in the catalyst, the amount of diethylene glycol, and the amount of carboxyl end groups. When recovering the polymer, it is preferable to recover it in the (I) layer from the viewpoint of taste characteristics.

The thickness of the coated polymer of the present invention is preferably 5 to 50 μm, more preferably 8 in terms of moldability after being laminated on a metal, film formability with respect to the metal, impact resistance, and taste characteristics. ~ 45 μm, more preferably 1
It is 0 to 40 μm.

Further, as a laminated polymer, the ratio of the thickness of the (I) layer to the thickness of the (II) layer is 20: 1 to 1: 1 (I:
II) is preferable in terms of taste characteristics and impact resistance, and 15: 1 to 4: 1 (I: II) is preferable in terms of impact resistance.

Further, the polymer of the present invention may contain 0.01 to 10% by weight of inorganic particles and / or organic particles having an average particle diameter of 0.1 to 10 μm in order to improve processability. It may be particle-free. However, it is not preferable to use particles having an average particle size of more than 10 μm because defects in the polymer layer are likely to occur. In particular, since it is not preferable to include particles of 30 μm or more, it is preferable to use a filter capable of drastically reducing foreign matters of 30 μm or more as an extrusion filter. 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, Examples thereof include organic particles containing divinylbenzene or the like as a constituent component. 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 (I) layer or the (II) layer, but it is preferable to add the particles to the (II) layer in order to improve the processability. On the other hand, particles may be added to the (I) layer as long as the characteristics are not impaired in terms of recovery.

Further, in producing the coated polymer of the present invention, additives such as a plasticizer, an antistatic agent and a weathering agent can be appropriately used if necessary.

Further, it is preferable to improve the adhesion by subjecting the (I) layer to a surface treatment such as a corona discharge treatment in order to further improve the characteristics. At that time, the E value is preferably 5 to 40, and more preferably 10 to 25.

The method for coating the polymer on the metal body of the present invention is not particularly limited as long as it is a melt extrusion laminate, but an example of the production method of the present invention will be described.

Isophthalic acid as polyester A 17.
5 mol% copolymerized polyethylene terephthalate ([η] =
0.84, diethylene glycol 0.7% by weight, melting point 2
15 ° C, carboxyl end group: 15 equivalent / ton) and SE
BS (styrene-ethylene / butylene-styrene block copolymer) 90:10 by weight, polyester B
As isophthalic acid 5 mol% copolymerized polyethylene terephthalate ([η] = 0.90, diethylene glycol 0.89% by weight, melting point 240 ° C., carboxyl end group:
14 equivalents / ton) of twin extruder type separate extruder (extruder temperature is melting point + 25 ° C ((I) layer side is polyester A)
(Melting point + 30 ° C.) and melted, and then laminated in two layers with a feed block (275 ° C. setting) and discharged from the die, so that (I) layer becomes a metal surface. A polymer plate having a thickness of 30 μm is applied to a metal plate having a thickness of about 3 mm. Immediately thereafter, the polymer-coated laminated metal body is obtained by cooling and solidifying to near room temperature with water or the like. Also,
It is preferable to apply a dustproof treatment to the laminating step because polymer defects are less likely to occur.

The metal body 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 to 15 g / m ^2, it is preferable to have a plating amount when nickel or aluminum 1.8~20g / m ^2.

The polymer-coated laminated metal body 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. Further, it can be preferably used for covering the lid portion of a two-piece can or the body, lid and bottom of a three-piece can as it has good metal adhesion, moldability and impact resistance. In particular, the colored polymers of the invention can be used for coating the outer surface. Therefore, a colorant can be blended in the polyester layer, and a white colorant, a red colorant or the like is preferably used as the colorant, and a colorant selected from titanium oxide, zinc white, inorganic or organic pigments is preferable. 5-
It is desirable to add 60% by weight, more preferably 15 to 50% 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.

[0043]

[Characteristics measurement and evaluation method] Characteristics are measured by the following methods.
evaluated.

(1) Content of diethylene glycol component in polyester It was measured by NMR (13 C-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 polyester in orthochlorophenol and prepare 25
It was measured at ° C. The insoluble polymer was filtered off and measured.

(4) Melting point of polyester Crystallization of polyester was carried out, and the temperature was 10 ° C./mi by a differential scanning calorimeter (DSC-2 type manufactured by Perkin Elmer Co., Ltd.).
It was measured at a heating rate of n.

(5) Acetaldehyde Content in Polyester 2 g of polymer fine powder was sampled and charged into a pressure vessel with ion-exchanged water, extracted with water for 60 minutes at 120 ° C., and then quantitatively determined by high sensitivity gas chromatography to determine the amount of acetaldehyde in the polyester. I asked.

(6) Oligomer content polymer in polyester 100 mg was dissolved in orthochlorophenol 1 ml and the solution was fractionated and then liquid chromatograph (Vari).
The cyclic trimer was measured with a model 8500 manufactured by An Co. and used as the amount of oligomer.

(7) Dispersion Diameter Ratio of Thermoplastic Elastomer A polymer cross section is cut to prepare an ultrathin section having a thickness of about 0.1 to 1 μm, and a magnification of 5000 to 2 is obtained by using a transmission electron microscope.
Photograph at about 0000 (longitudinal direction 25 cm × thickness direction 20)
(10 sheets of cm) were photographed, and the longitudinal diameter (xi) of each thermoplastic elastomer (i) dispersed in polyester A,
The thickness direction diameter (yi) and the ellipse equivalent area (Si) are measured. Then, the average dispersion diameter in the longitudinal direction (xav) and the average dispersion diameter in the thickness direction (yav) were calculated for each direction using the following formulas, and the dispersion diameter ratio (= xav / yav) was obtained.

[0051]

[Equation 3]

[Equation 4] (8) Impact resistance After tin-plated tin metal plate is coated with polymer, ironing machine (molding ratio (maximum thickness / minimum thickness) = 3.0)
And the bottom molding was performed to obtain a Draw Ironing can.

(Impact resistance with carbonated beverages) 220 after can making
Heat treatment at ℃ for 10 minutes, and fill with carbonated water at 0 ℃, 48
Carbonated bubbling for an hour. Then, after punching each 5 points from the outside of the can bottom with a punch, the contents were removed and the inside of the can was masked with wax, and 1% saline was put into the cup,
A voltage of 6 V was applied to the electrode in the saline solution and the metal can to read the current value, and the maximum value after measuring 10 cans was determined.

Class A: less than 0.1 mA Class B: 0.1 mA or more and less than 0.2 mA Class C: 0.2 mA or more and less than 0.5 mA Class D: 0.5 mA or more

(Impact resistance in retort beverages) 2 after canning
Bake at 20 ℃ for 10 minutes, and after baking at 20 ℃
× Retort treatment for 30 minutes, fill with commercially available oolong tea, leave at 30 ° C for 24 hours, impact with 5 points each from the outside of the can bottom with a punch, then remove the contents and mask the inside of the can with wax. Then, 1% saline solution was put into the cup, a voltage of 6 V was applied to the electrode and the metal can in the saline solution, the current value was read, and the maximum value after measuring 10 cans was determined.

Class A: less than 0.1 mA Class B: 0.1 mA or more and less than 0.2 mA Class C: 0.2 mA or more and less than 0.5 mA Class D: 0.5 mA or more

(9) Taste characteristics The polymer layer was left in contact with the perfume aqueous solution (d-limonene 30 ppm aqueous solution) (contact area: 314 cm ² ) at room temperature for 7 days, and then heated at 80 ° C. for 30 minutes in a nitrogen stream. The components to be expelled were subjected to gas chromatography to quantify the adsorbed amount of d-limonene per 1 g of the film to evaluate the taste characteristics.

Further, a perfume 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.

Grade A: No change in odor Class B: Almost no change in odor Class C: Change in odor

[0059]

【Example】

Example 1 As Polyester A, 17.5 mol% of isophthalic acid copolymerized polyethylene terephthalate (amount of germanium of 4
0 ppm, [η] = 0.84, diethylene glycol 0.70% by weight, melting point 215 ° C., carboxyl end group:
15 equivalents / ton) and SEBS (styrene-ethylene / butylene-styrene block copolymer, MI = 3.0 g)
/ 10 min, S / EB ratio 30/70) by weight ratio 90:
10, Polyester B 5 mol% isophthalic acid copolymerized polyethylene terephthalate (germanium element amount 4
0 ppm, [η] = 0.90, diethylene glycol 0.89% by weight, melting point 240 ° C., carboxyl end group:
14 equivalents / ton, silicon oxide particles having an average particle size of 4 μm.
2 wt%) to separate twin-screw vent type extruders (extruder temperature is set to melting point + 25 ° C. ((I) layer side is set to melting point + 25 ° C. for polyester A)) and melted. 2 layers in feed block ((I) layer / (II) layer = 9 /
1. After stacking at a set temperature of 270 ° C.) and discharging from a normal die, a steel plate having a thickness of 0.3 mm (Sn adhesion amount is 2.8 g / m ² on the outer surface side of the can) so that the (I) layer serves as an adhesion surface. , The inside 1 of the can
Tinplate steel sheet with chromate treatment to 00 mg / m ² )
Was extrusion-laminated (nip pressure at that time was about 80 kg / cm, laminating speed was 50 m / min), and immediately cooled in a water tank. The thus-obtained two-layer laminated coating polymer had a polyester component dissolved in a solvent to obtain an intrinsic viscosity of 0.80, an oligomer content of 0.6% by weight, an acetaldehyde amount of 18 ppm, a carboxyl end group of 21 equivalent / ton, and a dispersion diameter. The ratio was 6.0. Table 1 shows the physical properties and the results obtained by laminating on a metal plate and making a can. The polymer-coated metal laminate of the present invention containing an appropriate amount of thermoplastic elastomer was particularly excellent in both impact resistance and taste characteristics.

Examples 2 to 10 By changing the kind of thermoplastic elastomer, the lamination ratio, the kind of polyester, the kind of metal plate and the like, extrusion lamination was performed in the same manner as in Example 1. The results are shown in Tables 1 to 4.

In Example 2, polyester A and ethylene-
Propylene rubber (MI = 3.5 g / 10 minutes, E / P =
75/25) in a weight ratio of 92: 8, polyester B is polyethylene terephthalate (germanium element content 40 ppm, [η] = 0.90, diethylene glycol 0.89% by weight, melting point 250 ° C., carboxyl end group: 16). Equivalent / ton) and the laminating speed is 80m /
A polymer-coated metal laminate was obtained in the same manner as in Example 1 except that the content was changed. As shown in Table 1, good characteristics were obtained.

In Example 3, polyester A was used as isophthalic acid 12 mol% copolymerized polyethylene terephthalate (germanium element amount 42 ppm, [η] = 0.85, diethylene glycol 0.70 wt%, melting point 227 ° C., carboxyl terminal group: 14). Equivalent / ton), thermoplastic elastomer is ethylene-propylene rubber (MI = 3.5 g /
10 minutes, E / P = 75/25), and the weight ratio is 97:
3, the lamination ratio and the particle formulation of polyester B were changed, and a polymer-coated metal laminate was obtained in the same manner as in Example 1. As shown in Table 1, the impact resistance was slightly lowered.

In Example 4, polyester A was isophthalic acid 10 mol% copolymerized polyethylene terephthalate (germanium element amount 50 ppm, [η] = 0.72, diethylene glycol 0.80 wt%, melting point 235 ° C., carboxyl end group: 20 equivalents). / Ton), the thermoplastic elastomer is polybutadiene (MI = 1.0 g / 10 min),
The weight ratio of the particles of the polyester B was changed to 90:10, and a polymer-coated metal laminate was obtained in the same manner as in Example 1. As shown in Table 2, the intrinsic viscosity was small and the carbonic acid dent was slightly lowered, but good characteristics were obtained.

In Example 5, the intrinsic viscosity of polyester A was 0.70, the amount of diethylene glycol was 2.0% by weight,
Of polyester A and thermoplastic elastomer (EPR)
The weight ratio of 92: 8, terminal carboxyl group content of 4 6 equivalents /
A polymer-coated metal laminate was obtained in the same manner as in Example 1 except that the amount was changed to tons. As shown in Table 2, the intrinsic viscosity was low, the number of carboxyl end groups was large, and the dispersion diameter ratio was small, so the impact resistance was lowered.

In Example 6, polyester A was isophthalic acid 14 mol% copolymerized polyethylene terephthalate (antimony element amount 200 ppm, [η] = 0.86, diethylene glycol 0.50 wt%, melting point 223 ° C., carboxyl terminal group: 11). Equivalent / ton), thermoplastic elastomer SIS (MI = 3.0 g / 10 min, S / I = 20)
/ 80), the weight ratio was 90:10, and a polymer-coated metal laminate was obtained in the same manner as in Example 1 except that 10% of polybutylene terephthalate ([η] = 0.8) was mixed. Table 2
As shown in, good characteristics were obtained.

In Example 7, a polyester elastomer (HYTREL4057, thermoplastic elastomer) was used.
A polymer-coated metal laminate was obtained in the same manner as in Example 1 except that 10% by weight of MI = 13 g / 10 min) was blended.
As shown in Table 3, good characteristics were obtained.

In Example 8, the stacking ratio was 1: 2 ((I)).
Layer: A polymer-coated metal laminate was obtained in the same manner as in Example 1 except that the layer (II) was used. As shown in Table 3, the impact resistance was slightly lowered due to the large lamination ratio of the (II) layer, but the characteristics were good.

In Example 9, the type of the steel sheet was aluminum, and the (I) layer was made of Ciba-Gaigi "Irganox" 101.
Example 1 except that 0.05% by weight of 0 (antioxidant) was added and only the (I) layer was extruded to give a polymer thickness of 25 μm.
A polymer-coated metal laminate was obtained in the same manner as in. As shown in Table 3, good characteristics were obtained.

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[0070]

[0071]

[0072]

[0073]

Comparative Example 1 7 mol% isophthalic acid copolymerized polyethylene terephthalate (transesterification catalyst: magnesium acetate (magnesium element amount 170 ppm), dimethylphenylphosphonate (phosphorus element amount 410 ppm), antimony element amount 350 ppm, [η] = 0.62, diethylene glycol 2.0% by weight, melting point 239 ° C, acetaldehyde amount 3
A polymer-coated metal laminate was obtained with a single-screw extruder at an extrusion temperature of 290 ° C. at 7 ppm and 41 equivalents / ton of carboxyl terminal group. The results are shown in Table 4.

The polymer-coated metal laminate did not contain a thermoplastic elastomer, and the characteristics deteriorated.

Comparative Example 2 Polyester A was polybutylene terephthalate, and the extruder was an extruder equipped with a normal single screw.
A polymer-coated metal laminate was obtained in the same manner as in Example 3 except that only the (I) layer was extruded. The results are shown in Table 4. As can be seen from the table, impact resistance and taste characteristics were greatly deteriorated due to the small dispersion diameter ratio of the thermoplastic elastomer mainly composed of butylene terephthalate.

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[Table 1]

[Table 2]

[Table 3]

[Table 4]

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The polymer-coated metal laminate of the present invention has excellent impact resistance and taste characteristics when formed into cans and the like, and particularly has excellent low temperature impact resistance even after heat treatment during can manufacturing. And can be suitably used for a metal can manufactured by molding.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI B29K 67:00 B29K 67:00 B29L 9:00 B29L 9:00

Claims (6)

(57) [Claims] 1. A polyester A having a melting point of 140 to 245 ° C. and 70 mol% or more of the polyester component being ethylene terephthalate and / or ethylene isophthalate and a thermoplastic elastomer in a weight ratio of 70:30 to 9.
A polymer-coated metal laminate, which is obtained by coating a layer (I) blended in a ratio of 8: 2 by extrusion lamination. 2. The polymer-coated metal laminate according to claim 1, wherein the thermoplastic elastomer is a thermoplastic elastomer selected from a polystyrene-based thermoplastic elastomer and a polyester-based thermoplastic elastomer. 3. The dispersion diameter ratio (= longitudinal average dispersion diameter / thickness direction average dispersion diameter) of the thermoplastic elastomer is 2 to 100.
The polymer-coated metal laminate according to claim 1 or 2, wherein 4. (I) according to any one of claims 1 to 3.
A layer, a melting point of 220 to 260 ° C., by extrusion lamination and formed of polyester B is Gae Chi terephthalate 70 mol% or more of polyester component (II) layer, so that the metal side is the (I) layer side A polymer-coated metal laminate, characterized by being coated on. 5. The polymer-coated metal laminate according to claim 1, wherein the polyester component has a carboxyl terminal group amount of 35 equivalents / ton or less. 6. The polymer-coated metal laminate according to any one of claims 1 to 5, wherein the polyester component has an intrinsic viscosity [η] of 0.7 or more.