JP5664529B2 - LAMINATED METAL PLATE MANUFACTURING METHOD AND LAMINATED METAL PLATE - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for producing a high-quality laminated metal plate and a laminated metal plate that are optimal for building materials used for containers, interior panels, and the like that are filled with food, medicine, and the like.

  In recent years, laminated metal plates have been used as materials for food cans and beverage cans. Laminated metal plates are made by coating a thermoplastic resin layer on a metal plate such as tinplate, tin-free steel (hereinafter abbreviated as TFS), aluminum plate, etc. There is no need for volatilization, and there is no need for washing cans after processing cans and no wastewater is generated.

  Polyolefin resins such as polyester resins and polypropylene are mainly used as resins used for such laminated metal plates, but polyester resins with excellent flavor preservation are used especially for food cans and beverage cans. It tends to be. In addition to the commonly used homo-type polyethylene terephthalate resin, the polyester resin used in the container is a copolymer in which components such as isophthalic acid, butylene glycol, and cyclohexane dimethanol are copolymerized for severely workable applications. A polymerization type polyethylene terephthalate resin is used. Furthermore, recently, a polyester resin composited with an ionomer has been studied as a polyester-based resin that has excellent mechanical properties such as workability and impact resistance and is suitable for container materials. For example, Patent Document 1 and Patent Document 2 propose resins in which an ionomer is contained in a polyester resin with a limited resin composition. Patent Documents 3 and 4 propose polyester resins containing ionomers whose resin composition and physical properties are specified. Further, Patent Document 5 discloses a technique for suppressing thermal degradation of a resin by mixing a polyester resin with a radical inhibitor together with an ionomer.

JP-A-7-195617 Japanese Unexamined Patent Publication No. 7-195618 Japanese Patent Laid-Open No. 2003-320615 JP 2003-165177 A Japanese Patent No. 3545771

  However, the polyester resin composited with ionomers as described in Patent Documents 1 to 4 deteriorates when the ionomer reacts with the polyester resin and gels, so that the film edge generated after extrusion is not necessary. The resin (which is referred to as a shoulder) cannot be reclaimed as it would normally be done by breaking, drying, and adding to a new resin, resulting in an increase in cost and an increase in resin dust, leading to adverse effects on the environment. Further, as described in Patent Document 5, it is difficult to completely suppress thermal degradation even when a radical inhibitor is mixed.

  In view of the above circumstances, the present invention uses a recycled resin that has excellent mechanical properties equivalent to those of a polyester resin combined with an ionomer, is recyclable, is advantageous in cost, and has little environmental damage. It is an object of the present invention to provide a method for producing a laminated metal plate and a laminated metal plate.

  The present inventors have studied a recycled polyester resin that is recyclable and has excellent mechanical properties as a container material. It is preferable to use a polyester resin containing a polyolefin resin modified with a carboxylic acid as the recycled polyester resin. I found out.

  The present invention has been made on the basis of such findings, recycled polyester containing 5% by mass or more and 30% by mass or less of a polyolefin resin modified with a carboxylic acid in which the proportion of the monomer containing carboxylic acid is 6 to 16% by mass. There is provided a method for producing a laminated metal sheet, wherein a polyester-based resin layer containing 25% by mass or more of resin is melt-extruded from a T-die to form a film, and the film is laminated on at least one surface of the metal sheet.

  The present invention also provides a polyester containing 25% by mass or more of a regenerated polyester resin containing 5% by mass or more and 30% by mass or less of a polyolefin resin modified with a carboxylic acid in which the proportion of the monomer containing carboxylic acid is 6 to 16% by mass. Provided is a method for producing a laminated metal plate, characterized in that a resin layer is melt-extruded directly from at least one side of a metal plate through a T-die and laminated.

  According to the production method of the present invention, the recycled polyester resin containing 5% by mass or more and 30% by mass or less of the polyolefin resin modified with carboxylic acid in which the ratio of the monomer containing carboxylic acid is 6 to 16% by mass is contained by 25% by mass or more. A laminated metal plate characterized by laminating a polyester resin layer on at least one surface of a metal plate can be produced.

  According to the present invention, it is possible to manufacture a laminated metal plate using a regenerated polyester resin that is recyclable, does not generate dust, has little damage to the environment, and has excellent mechanical properties as a container material. The laminated metal plate of the present invention is optimal for uses such as containers, cans, and building materials.

  A polyester resin containing an ionomer is likely to cause defects in a film or the like produced by melt extrusion because the ionomer reacts with the polyester resin to gel or hydrolyze. Also, due to the reactivity, the reaction with the polyester resin proceeds during the melt extrusion, and the resin is deteriorated. For this reason, the polyester resin containing an ionomer cannot be recycled by drying unnecessary resin after extrusion. Even if it is recycled, the amount that can be mixed with the new resin must be kept low.

  Accordingly, the present inventors have studied a composition of a resin that does not react with the polyester resin and that is mixed with the polyester resin to improve mechanical properties. As a result, the polyester resin containing 5% by mass or more and 30% by mass or less of a polyolefin resin modified with a carboxylic acid in which the ratio of the monomer containing the carboxylic acid is 6 to 16% by mass is hardly deteriorated by melt extrusion. It has been found that there is no adverse effect even if a large amount is regenerated and mixed with new resin. This recycled polyester resin containing polyolefin resin modified with carboxylic acid is mixed with new resin of the same composition, or mixed with other new polyester resin not containing carboxylic acid modified olefin resin. It can be used as a resin layer. In any case, the recycled polyester resin containing the polyolefin resin modified with the carboxylic acid is contained in the resin layer of the laminated metal plate in an amount of 25% by mass or more in order to ensure excellent mechanical properties as a container material. is necessary. At this time, the proportion of the monomer containing carboxylic acid is suitably 6 to 16% by mass. This is because in this composition range, the affinity with the polyester resin is high, the dispersibility in the polyester resin is high, and the reactivity with the polyester resin is sufficiently small. If the amount of the carboxylic acid-containing monomer is less than 6% by mass, the mechanical properties of the polyester resin are not improved, and if it exceeds 16% by mass, the polyester resin may react with the polyester resin and deteriorate. If the weight ratio of the carboxylic acid-modified polyolefin resin in the recycled polyester resin is less than 5% by mass, it is insufficient to improve the mechanical properties of the polyester resin layer, and if it exceeds 30% by mass, the resin layer is processed. Decrease the heat resistance and heat resistance.

  Moreover, the recycled polyester resin containing carboxylic acid modified polyolefin resin should just satisfy the said range for the quantity of carboxylic acid modified olefin resin as a total. Further, even when regenerated and mixed with a new resin, it is necessary that the resin layer contains a regenerated polyester resin containing 25% by mass or more of the regenerated carboxylic acid-modified polyolefin resin.

  The reason why the carboxylic acid-modified polyolefin resin does not react with the polyester resin and does not deteriorate the resin is that the resin has a high affinity with the polyester resin and does not contain a metal such as an ionomer. This is because the resin does not react with the resin and deteriorate. In addition, since the carboxylic acid-modified polyolefin resin is dispersed in a fine granular form in the polyester resin, the mechanical properties are improved by relieving stress during processing and impact. The carboxylic acid-modified polyolefin resin is preferably present in the state of 0.1 to 5 μm particles dispersed in the polyester resin by an equivalent sphere equivalent meter.

  The regenerated polyester resin containing the carboxylic acid-modified polyolefin resin can be regenerated by, for example, finely crushing the edge portion with a cutter or a crusher and then drying at 80 ° C. or higher, preferably 120 ° C. or higher for 3 hours or longer. After drying, it is mixed with a new polyester resin and melt-extruded from a T-die to form a film, or extruded as it is and laminated to a metal plate to produce a laminated metal plate.

The glass transition temperature of such a modified olefin resin is preferably 0 ° C. or lower, more preferably −30 ° C. or lower. When the glass transition temperature exceeds 0 ° C., the impact resistance is slightly inferior, and particularly the low temperature impact resistance is inferior. The Young's modulus at room temperature is preferably 250 MPa or less and the elongation at break is preferably 200% or more, more preferably the Young's modulus is 100 MPa or less and the elongation at break is 500% or more. The molecular weight is not particularly limited, but the number average molecular weight is preferably 2 × 10 ³ or more and 1 × 10 ⁶ or less. If it is less than 2 × 10 ³ or exceeds 1 × 10 ⁶ , the mechanical properties may be inferior, impact resistance may be reduced, and processing may be difficult.

  The carboxylic acid-modified polyolefin resin can be produced by copolymerizing a monomer containing a carboxylic acid into the polyolefin resin. Examples of the monomer containing carboxylic acid include acrylic acid, methacrylic acid, vinyl acetate, vinyl propionate, maleic acid, maleic anhydride, itaconic acid, maleic acid monomethyl ester, etc. However, acrylic acid or methacrylic acid is superior in terms of mechanical properties. As such a carboxylic acid-modified polyolefin resin, a commercially available resin can also be used, and examples thereof include Nucrel manufactured by Mitsui DuPont Polychemical Co., Ltd.

  Next, the thermoplastic polyester resin that is the main component of the resin layer of the laminated metal plate will be described. Polyester resins used in applications such as carbonated beverage cans have excellent adhesion to metal plates, and are resistant to deformation and deformation due to elongation, compression, etc. due to processing during canning and adhesion to metal plates. No degradation, no drying, printing and baking after canning, retort sterilization, etc., no peeling, shrinkage, cracks, pinholes, etc., no impact on the can, no cracking or peeling In addition, it is required to have performances such as no corrosion or peeling when in contact with various contents and no cloudiness. Furthermore, it is also required that the scent component of the contents of the can is adsorbed on the resin layer, and that the flavor of the contents is not impaired by the eluted components and odor in the resin layer.

  In the present invention, as a thermoplastic polyester resin that satisfies these requirements, various aromatic dicarboxylic acids and aliphatic dicarboxylic acids are optionally polymerized or copolymerized as glycol components, and various aliphatic diols and aromatic diols as glycol components. And those obtained by mixing two or more types of copolymer polyester resins having different compositions are used.

  As the acid component, terephthalic acid or isophthalic acid is preferable. Acid components other than terephthalic acid and isophthalic acid include phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4 '-Biphenyldicarboxylic acid, diphenic acid, diphenyl ether carboxylic acid, 5-sulfoisophthalic acid, diphenoxyethanedicarboxylic acid, adipic acid, oxalic acid, malonic acid, succinic acid, malic acid, citric acid, glutaric acid, dimer acid, pimeline Acid, peric acid, azelaic acid, sepacic acid, dodecadioic acid, trans-1,4-cyclohexanedicarboxylic acid and the like can be used.

  As the glycol component, those obtained by arbitrarily polymerizing or copolymerizing various aliphatic diols and aromatic diols are used, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1, 2-butanediol, neopentyl glycol, pentamethylene glycol, hexamethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, trans-1,4-cyclohexanedimethanol, cis-1,4-cyclohexanedimethanol, Bisphenols, p-xylene glycol, hydroquinone, 2,2-bis (4-β-hydroxyethoxyphenyl) propane, hydrogenated bisphenol A, and the like are used. In particular, those based on ethylene glycol and / or 1,4-butanediol and / or 1,4-cyclohexanedimethanol are preferred from the standpoint of balance between mechanical properties and flavor properties.

  Thus, terephthalic acid and ethylene glycol are the main components, and / or terephthalic acid and isophthalic acid and ethylene glycol are the main components, and / or terephthalic acid and ethylene glycol and 1,4-butanediol, and / or terephthalic Those having acid, ethylene glycol and 1,4-cyclohexanedimethanol as main components are suitable as polyester resins from the viewpoint of mechanical properties in the mixed resin state.

  Furthermore, a small amount of a structural unit derived from a polyfunctional compound such as trimesic acid, pyromellitic acid, trimethylol ethane, trimethylol propane, trimethylol methane, pentaerythritol, etc., as long as the object of the invention is not impaired, for example, 2% by weight. It may be included in the following amounts.

  A resin as a raw material is obtained by adding a carboxylic acid-modified olefin resin to a polyester resin. As a dispersion method, for example, a polyester resin is produced by polymerizing a monomer in a solution containing a modified olefin resin having a primary particle size reduced to 1 μm or less and a polyester resin constituent monomer, and the modified olefin resin is dispersed in the polyester. There are a method to make it in a state of being melted, a method in which two resins are melted and mixed, and a modified olefin resin is refined by mechanical shearing force, etc. It is also possible to mix at the time of resin extrusion and melt and mix in an extruder It is. As an apparatus for mixing and melting, a mixing apparatus such as a tumbler blender, a Henschel mixer, and a V-shaped blender, and a melt mixing apparatus such as a single or twin screw extruder, a kneader, and a Banbury mixer can be used.

  The intrinsic viscosity of the polyester resin used in the present invention is 0.3 to 2.0 dl / g, preferably 0.3 to 1.5 dl / g, more preferably 0.5 to 1.0 dl / g. If it exceeds 2.0 dl / g, the viscosity is so high that mixing with the modified olefin resin used in the present invention becomes extremely difficult, and the effect of the present invention may be insufficient as a result of the resin not being uniformly dispersed. There is. On the other hand, when the intrinsic viscosity is less than 0.3 dl / g, the mechanical strength of the polyester resin is low, which is not suitable. This intrinsic viscosity is measured at a concentration of 0.005 g / ml in o-chlorophenol at 25 ° C. based on JIS K7367-5, and is obtained from the formula of intrinsic viscosity = (T-T0) / (T0 * C). . Here, C represents the concentration of the resin per 100 ml of the solution expressed in grams, and T0 and T represent the flow-down time of the solvent and the resin solution in the capillary viscometer, respectively.

  The polyester resin used in the present invention preferably has a glass transition temperature (Tg) of 50 to 100 ° C. More preferably, it is 60-80 degreeC. When the glass transition temperature is less than 50 ° C, the heat resistance of the polyester resin is inferior, so that scratches are easily generated due to the temperature rise during processing. On the other hand, when the glass transition temperature exceeds 100 ° C, workability is reversed. May be inferior. The low temperature crystallization temperature (Tc) is usually 120 to 210 ° C, preferably 140 to 200 ° C, and the melting point (Tm) is usually 210 to 265 ° C, preferably 220 to 260 ° C. If the low-temperature crystallization temperature is less than 120 ° C, crystallization is likely to occur, so that crystallization occurs during retort sterilization (high temperature and high humidity treatment of about 120 ° C), and the polyester resin is likely to crack or peel off. On the other hand, when the low-temperature crystallization temperature exceeds 210 ° C., the mechanical strength such as processability and impact resistance of the polyester resin may be inferior. When the melting point is less than 210 ° C., the resin deteriorates due to heat during processing, and cracks and pinholes are likely to occur. On the other hand, when the melting point exceeds 265 ° C., crystallization proceeds by heat treatment such as drying during processing and printing baking, and cracks and pinholes are likely to occur. The glass transition temperature, low-temperature crystallization temperature, and crystal melting temperature were measured using a differential scanning calorimeter (DSC) with a sample amount of 10 mg and a temperature increase rate of 10 ° C / min. It is the value.

  The resin film can contain inorganic particles, organic particles, and organic polymer particles for the purpose of improving slipperiness, workability, impact resistance, and the like. Inorganic particles include silica produced by dry and wet methods, porous silica, colloidal silica, titanium oxide, zirconium oxide, aluminum oxide, calcium carbonate, talc, calcium sulfate, barium sulfate, spinel, iron oxide, calcium phosphate Examples of organic particles or organic polymer particles include polystyrene particles, crosslinked polystyrene particles, styrene-acrylic crosslinked particles, acrylic crosslinked particles, styrene-methacrylic acid resin crosslinked particles, and methacrylic acid resin crosslinked particles. Examples thereof include vinyl resin-based particles such as particles, and organic polymer particles containing silicone, benzoguanamine-formaldehyde, polytetrafluoroethylene, polyphenyl ester, phenol resin, and the like as constituent components. The particle diameter and content of these particles are not particularly limited, but the particle diameter is preferably in the range of 0.01 to 5.0 μm, more preferably in the range of 0.1 to 2.5 μm in order to maximize performance. Their particle size distribution is sharp and a standard deviation of 0.5 or less is preferable. Further, the particle shape is preferably close to a true sphere, and the ratio of major axis / minor axis is more preferably 1.0 to 1.2.

  Further, in the resin film, as long as the effects of the present invention are not hindered, the light stabilizer, the impact resistance improver, the compatibilizer, the lubricant, the plasticizer, the antistatic agent, the reaction catalyst, the coloring inhibitor, and the radical inhibitor. Further, additives such as a plasticizer, an antioxidant, a terminal blocking agent, a heat stabilizer, a release agent, a flame retardant, an antibacterial agent, and an antifungal agent may be further added. The content of these additives is preferably 0.005 to 15 parts by weight with respect to 100 parts by weight of the resin. More preferably, it is 0.01 part by weight or more and 2 parts by weight or less, and particularly preferably 0.05 part by weight or more and 0.5 part by weight or less. If the amount is less than 0.005 parts by weight, the effect is insufficient. If the amount exceeds 15 parts by weight, the additive becomes excessive and the mechanical performance of the resin layer is lowered. In addition, heat resistance of 200 ° C. or higher is required so as not to deteriorate during resin processing.

  Examples of the reaction catalyst include alkali metal compounds, alkaline earth metal compounds, zinc compounds, lead compounds, manganese compounds, cobalt compounds, and aluminum compounds. Examples of the coloring inhibitor include phosphorus compounds. Examples of the radical inhibitor include one or more selected from phenol-based radical inhibitors, phosphorus-based radical inhibitors, sulfide-based radical inhibitors, and nitrogen-based radical inhibitors.

  It is also possible to add a polyester resin polymerization catalyst into the resin. The polymerization catalyst preferably contains 1 ppm or more and 500 ppm or less of at least one element selected from germanium, antimony, and titanium. More preferably, it is 3 ppm or more, and further preferably 10 ppm or more. If the amount of at least one element selected from germanium, antimony, and titanium is less than 1 ppm, the effect of improving the flavor may not be sufficient, and if it exceeds 500 ppm, foreign matter is generated in the polyester resin to form crystal nuclei. Therefore, the impact resistance may deteriorate or the heat resistance may decrease. Of these elements, germanium is particularly preferred from the viewpoint of flavor.

  As the germanium compound, for example, germanium dioxide, germanium oxide such as germanium hydroxide containing crystal water, hydroxide, or germanium alkoxide compound such as germanium tetramethoxide, germanium tetraethoxide, germanium tetrabutoxide, germanium ethyleneglycoxide, Examples thereof include germanium phenoxide compounds such as germanium phenolate and germanium β-naphtholate, phosphorus-containing germanium compounds such as germanium phosphate and germanium phosphite, and germanium acetate. Examples of antimony compounds include antimony trioxide, antimony trifluoride, antimony acetate, antimony borate, antimony formate, antimony acid, and the like, and titanium compounds include oxides such as titanium dioxide, titanium hydroxide, and the like. Examples include hydroxides, tetramethoxy titanates, tetraethoxy titanates, tetrapropoxy titanates, tetraisopropoxy titanates, alkoxide compounds such as tetrabutoxy titanates, glycoxide compounds such as tetrahydroxyethyl titanates, phenoxide compounds, and acetates.

Next, the metal plate that covers the resin film will be described. Although the metal plate of this invention is not specifically limited, The metal plate which uses iron and aluminum as a raw material is preferable at the point of workability. In the case of a metal plate made of iron, in order to improve resin adhesion and corrosion resistance on the surface, an inorganic oxide film layer such as chromic acid treatment, phosphoric acid treatment, chromic acid / phosphoric acid treatment, electrolytic chromic acid treatment, You may provide the chemical conversion treatment coating layer represented by the chromate process. Further, a spreadable metal plating layer, for example, a plating layer of nickel, tin, zinc, aluminum, gun metal, brass or the like may be provided. Furthermore, in the case of tin plating, 0.5 to 15 g / m ^2, having a plating weight of the case of nickel or aluminum 1.8~20g / m ² is particularly preferable from the viewpoint of processability and resin adhesion. The thickness of such a metal plate is usually 0.01 to 5 mm, preferably 0.1 to 2 mm. And the resin coating layer which coat | covered the resin composition of this invention is formed on the single side | surface or both surfaces of a metal plate.

In the case of a metal plate made of iron, an electrolytic chromated steel plate is particularly preferable from the viewpoints of adhesion to the resin film of the present invention, corrosion resistance, and production cost. Metallic chromium amount of the metal chromium layer is suitably 50-200 mg / m ^2, corrosion resistance is less than 50 mg / m ^2, may adhesion after processing is insufficient, corrosion resistance exceeds 200 mg / m ^2, processing The effect of improving the subsequent adhesion is saturated, and the manufacturing cost increases. Moreover, 3-30 mg / m < ² > is suitable for the metal chromium conversion amount of the chromium amount in chromium oxide. When the amount is less than 3 mg / m ² , the adhesion may be inferior, and when it exceeds 30 mg / m ² , the color tone deteriorates and the adhesion is also inferior.

  As for the method of laminating the resin film on the metal plate, a method of laminating the resin film by pressing it with a rotating roll on a metal plate heated in the range of the melting point of the polyester resin to -70 ° C to (melting point +30) ° C is preferable.

  As for the extrusion laminating method, a method in which rolls are arranged on both surfaces of the metal plate and the molten resin is pressed against the metal plate and laminated is preferable.

An ethylene phthalate-ethylene isophthalate copolymer resin (inherent viscosity 0.6 dl / g, Tg 70 ° C., Tc 170 ° C., Tm 230 ° C., Ge content 10 ppm) having a terephthalic acid and isophthalic acid ratio of 90:10, as shown in Table 1. After the unnecessary (shoulder) resin generated in the production process of the polyester composite resin made of modified polyolefin resin is dried in a 120 ° C vacuum dryer for 5 hours, it is mixed with the composite resin shown in Table 1 and supplied to the extruder. The film was extruded from a T-die with a single-screw extruder, and an unstretched film having a thickness of 25 μm was produced using a cooling drum. Here, the following were used as modified olefin resin.
1) E1: LLDPE (Evolue SP4030 manufactured by Prime Polymer Co., Ltd.)
2) M2: Ethylene-methacrylic acid copolymer (Nucrel AN4214C manufactured by Mitsui Dupont Polychemical Co., Ltd.)
3) M3: Ethylene-methacrylic acid copolymer (Nucrel N0903HC manufactured by Mitsui Dupont Polychemical Co., Ltd.)
4) M4: Ethylene-methacrylic acid copolymer (Nucrel N1525 manufactured by Mitsui DuPont Polychemical Co., Ltd.)
5) M5: ethylene-methacrylic acid copolymer Zn neutralized product (High Milan 1705 manufactured by Mitsui DuPont Polychemical Co., Ltd.)
As the metal plate, TFS having a thickness of 0.18 mm, a tempering degree DR9, a metal chromium layer of 80 mg / m ² , and a chromium oxide layer of 15 mg / m ² (in terms of metal chromium) was used for a thin-walled deep drawn can.

  Then, the resin film obtained as described above was thermocompression bonded to both surfaces of this metal plate heated by the induction heating method, and then laminated by a thermal bonding method that was quenched in water to produce a laminated metal plate.

The laminated metal plate thus produced was processed into a can by the following method and subjected to strain relief heat treatment to obtain a thin-walled deep-drawn can.
(1) Can manufacturing process The above-mentioned laminated metal plate was subjected to first stage drawing and redrawing under the following conditions to obtain a thinned deep drawn can.
・ First stage aperture Blank diameter: 150 ~ 160mm
Aperture ratio: 1.65
・ Re-drawing First re-drawing: 1.25 aperture ratio
Second re-drawing: Aperture ratio 1.25
Curvature radius of die corner in redrawing process: 0.4mm
Wrinkle hold weight during redrawing: 39227N (4000kg)
-Average thinning ratio of the can body 40-55% of the thickness of the resin-laminated metal plate before processing
(2) Strain-removing heat treatment The processing strain of the film introduced in the can manufacturing process was removed by heating and holding at 220 ° C. for 30 seconds and then rapidly cooling.

And the processability of the film of a thin-walled deep-drawn can body, impact resistance, and the adhesiveness after a process were evaluated with the following method.
(i) Workability The limit working degree (thinning ratio) that can be processed without film damage was evaluated as follows. In addition, a pass is a thing of evaluation more than (circle).
Thinning rate: 40%
Thinning rate can be processed up to 40%: △ ↑
Thinning rate up to 45% is possible: ○
Possible to process up to 50% thinning rate: ◎ ↓
Thinning rate up to 55% can be processed: ◎◎ (excellent)
(ii) Impact resistance After applying neck processing to the can body (thinning ratio 50%) subjected to strain relief heat treatment, filling the can body with distilled water, attaching a lid and tightening, A 0.5 kg iron ball was dropped from a height of 30 cm to give an impact. Next, open the lid, fill the inside of the can with 1% saline so that the impacted part is immersed, and after immersion for 5 minutes, apply a 6 V load to the platinum electrode immersed in the liquid and the can metal part, Furthermore, the current value after 1 minute was read and evaluated as follows. In addition, a pass is a thing of evaluation more than (circle).
Current value is 30 mA or more: × (poor)
Current value is 10mA or more and less than 30mA: △ ↑
Current value is 5 mA or more and less than 10 mA: ○
Current value is 1 mA or more and less than 5 mA: ◎ ↓
Current value is less than 1 mA: ◎◎ (excellent)
(iii) Adhesiveness after processing After cleaning the inner surface of the can body that has been subjected to the strain relief heat treatment and immersing it in an aqueous solution of 1.5% by weight of citric acid-1.5% by weight of sodium chloride for 24 hours, the length of the resin peeled off at the tip of the can Were observed and evaluated as follows. In addition, a pass is a thing of evaluation more than (circle).
Peeling exceeding 10 mm: × (poor)
Peel off over 5mm and below 10mm: △ ↑
Peel off over 2mm and below 5mm: ○
2mm or less peeling: ◎ ↓
No peeling: ◎◎ (excellent)
The results are shown in Table 1.

  From Table 1, since the laminated metal plate of the present invention has few defects and excellent film forming properties, it is excellent in workability, impact resistance, and adhesion after processing. In addition, it has excellent mechanical properties equivalent to those of polyester resins combined with ionomers.

  An ethylene phthalate-ethylene isophthalate copolymer resin (inherent viscosity 0.6 dl / g, Tg 70 ° C., Tc 170 ° C., Tm 230 ° C., Ge content 10 ppm) having a terephthalic acid and isophthalic acid ratio of 90:10, as shown in Table 2. After the unnecessary (shoulder) resin generated in the production process of the polyester composite resin made of modified polyolefin resin is dried in a 120 ° C vacuum dryer for 5 hours, it is mixed with the composite resin shown in Table 2 and supplied to the extruder. A laminated metal plate was produced by extruding from a T-die with a single screw extruder and melt extruding to a thickness of 25 μm on both sides of the metal plate. Resin symbols and the like are the same as in Example 1.

As the metal plate, TFS having a thickness of 0.18 mm for thin-walled deep drawn cans, a tempering degree DR9, a metal chromium layer of 80 mg / m ² , and a chromium oxide layer of 15 mg / m ² (metal chromium equivalent) was used.

  The laminated metal plate thus produced was made into a thin-walled deep drawn can as in Example 1, and the same evaluation as in Example 1 was performed.

  The results are shown in Table 2. Since the laminated metal plate of the present invention has few defects and excellent film forming properties, it is excellent in workability, impact resistance, and adhesion after processing.

Claims (3)

  Polyester resin comprising 25% by mass or more of regenerated polyester resin containing 8% by mass or more and 30% by mass or less of a polyolefin resin modified with carboxylic acid in which the ratio of the monomer containing carboxylic acid is 6 to 16% by mass, and an ionomer. A method for producing a laminated metal sheet comprising: a polyester-based resin layer not containing selenium is melt-extruded from a T-die to form an unstretched film, and the unstretched film is laminated on at least one surface of the metal sheet.   Polyester resin comprising 25% by mass or more of regenerated polyester resin containing 8% by mass or more and 30% by mass or less of a polyolefin resin modified with carboxylic acid in which the ratio of the monomer containing carboxylic acid is 6 to 16% by mass, and an ionomer. A method for producing a laminated metal plate, comprising: laminating a polyester-based resin layer not containing bismuth by directly melt-extruding at least one surface of a metal plate from a T-die. Polyester resin comprising 25% by mass or more of regenerated polyester resin containing 8% by mass or more and 30% by mass or less of a polyolefin resin modified with carboxylic acid in which the ratio of the monomer containing carboxylic acid is 6 to 16% by mass, and an ionomer. Laminate a polyester-based resin layer not containing at least one side of the metal plate,
The polyester resin layer is laminated in an unstretched state, and is a laminated metal plate.