JPH11124447A - Film for laminating metallic plate and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject film having each specific planar orientation degree and thermal property, excellent in heat resistance and thermocompression bonding effect at low temperatures, and capable of giving laminated metallic plates of excellent formability and processability and also giving cans of high impact resistance, by including a polyethylene terephthalate(PET)-based polyester, a polybutylene terephthalate(PBF)-based polyester, and a polyarylate. SOLUTION: This film is obtained from a resin composition comprising (A) PET or a polyester predominant therein, (B) PBT or a polyester predominant therein, and (C) a polyarylate. This film has the following characteristics: the content of the component C is 5-40 wt.%, planar orientation degree is 0.08-0.16, there are two or more melting points derived from the resin composition only within the temperature range 200-250 deg.C, and such a thermal property as to be 25-45 J/g in the sum of the heat of fusion [ΔHm] derived from the crystal portion in the resin composition is satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film useful as a constituent material of a film-laminated metal plate particularly suitable for use as a metal can, and a method for producing the film.

[0002]

2. Description of the Related Art Metal cans, which are one form of food and beverage packaging containers, have excellent mechanical strength and excellent sealing properties, so that the contents can be stored for a long time, and the contents can be filled at a high temperature. It can be easily sealed and can be easily sterilized by retort treatment, etc., so it is highly reliable for safety and hygiene as a packaging container.Furthermore, the contents can be stored in a heated state and the can In recent years, various types of contents have been filled and used in large quantities because of their many advantages that separation and collection are relatively easy.

[0003] The inner and outer surfaces of a metal can for food and drink are intended to maintain the flavor of the contents, prevent corrosion of the metal can material, improve the external appearance of the can, and protect the printed surface. Conventionally, a solvent-based paint mainly containing a thermosetting resin has been applied. However, such a paint can has the following problems. (A) When a heating treatment such as a retort treatment is performed after filling and sealing the content, low molecular weight substances such as a residual solvent in the coating film migrate into the content, and the flavor of the content is significantly reduced.
(Inferior in flavor) (b) As the diameter of the can lid becomes smaller and the thickness of the can becomes thinner, workability and impact resistance of the paint film are required more than before, while the paint film becomes white after retort treatment. Although retort resistance is required for problems such as film formation and peeling of the coating film, it is difficult to obtain a coating film that simultaneously satisfies these performances. (C) A large amount of an organic solvent is used, and a large amount of thermal energy is required for drying and baking the coating film.

In recent years, a metal can manufactured using a film-laminated metal plate obtained by laminating a single-layer or multi-layer plastic film on a metal plate has attracted attention. In particular, polyester film
It has the advantages of excellent mechanical strength, workability, heat resistance, hardly causing pinholes and cracks, less losing the flavor of the contents (excellent in flavor), and being relatively inexpensive. Practical application is underway.

[0005] As a method of laminating a plastic film to a metal plate, an adhesive layer is provided in advance on at least one of the plastic film and the metal plate, and a heat bonding method is used. And the like. In the former method, when an adhesive consisting of a solution in which an uncured thermosetting resin is dissolved in an organic solvent is used, the above-mentioned problems (a) and (c) and the problem of the problem between the adhesive layer and the film. Since an interface is formed, there is a problem in the workability of the laminated metal plate and the impact resistance of a can (laminated can) obtained from the laminated metal plate. On the other hand, when the latter method is used, the above problems (a) to (c) are solved, and the productivity of the metal can is improved.

For example, JP-A-64-22530, JP-A-2-305827, and JP-A-3-867
No. 29, JP-A-5-154971, JP-A-5
JP-147647, JP-A-5-156040, JP-A-6-39979, JP-A-6-1163
74, JP-A-7-207040, JP-A-7-207040
JP-195617, JP-B-57-23584, JP-B-7-35092, JP-B-7-8025
No. 3 discloses a polyester film that can be thermocompressed. Also, JP-A-58-220729, JP-A-60-170532, and JP-A-3-57
No. 514, JP-A-3-101930, JP-A-3-212433, JP-A-5-92535, JP-B-57-22750, and the like disclose a laminated metal plate using a thermocompression-bondable polyester film. And a method for producing a metal can body having a high drawing ratio.

Meanwhile, the conventional polyester film for laminating a metal plate has other components for the purpose of maintaining the thermocompression bonding property, the processability of the laminated metal plate, and the impact resistance as a metal can body. The degree of crystallinity of the film has been reduced by copolymerizing or blending the same. However, when a conventional polyester film for metal plate lamination is used, low-molecular weight substances in the film tend to migrate to the contents during high-temperature treatment such as retort treatment, and the flavor of the contents is impaired, and in some cases, There are various problems such as the phenomenon that the contents are altered, the film is crystallized during retort treatment, the film is peeled, microcracks are generated, or the spherulites grow and the film is whitened. And the impact resistance of the resulting can is insufficient.

[0008] The workability of the laminated metal plate and the impact resistance of the laminated can are increased (measures are usually made to reduce the crystallinity of the film), and the flavor of the metal can is improved (measures include: In order to balance performances such as increasing the crystallinity of the film, it has been proposed to devise thermocompression bonding conditions (JP-A-5-925).
No. 35, JP-A-7-195651, JP-A-7-195561
JP-B-223646, JP-B-7-85923,
In this case, the temperature and laminating speed of the steel plate and the heat roll, etc., must be uniformly and accurately controlled, and the equipment and facilities become very expensive, and the economy is lost. There was a problem that it would.

On the other hand, the present inventors have previously used a biaxially stretched film made of a polyester resin composition in which polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) are mixed at a specific ratio. (Japanese Patent Application Laid-Open No. 9-194604), it has been found that the thermocompression bonding properties at low temperatures are not sufficient and the resulting laminate cans may have poor impact resistance. did.

[0010]

DISCLOSURE OF THE INVENTION The present invention relates to (a) excellent mechanical properties and heat resistance, (a) thermocompression bonding with a metal plate even with a high degree of crystallinity, and The quality of the laminated metal plate does not easily change due to changes in conditions during thermocompression bonding to the plate, and can be thermocompression-bonded even at a low temperature of 200 ° C. or less. It has excellent moldability and can produce deep drawing ratio cans and drawn ironing cans. (D) When laminated cans are used, they have excellent retort resistance, flavor, impact resistance, and printability. It is an object of the present invention to provide a film for laminating a metal plate and a method for producing the same, which can obtain a film.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that PET or a polyester (A) mainly composed thereof and PBT or a polyester (B mainly composed thereof). ), A film having specific thermal characteristics using a polyester resin composition in which polyarylate is blended in a specific ratio is excellent in thermocompression bonding at low temperatures,
In addition, the formability and workability of the laminated metal sheet using this,
Furthermore, they have found that the impact resistance of a can body is remarkably improved, and arrived at the present invention.

That is, the gist of the present invention is as follows. (1) PET or polyester mainly composed of PET (A)
And PBT or a polyester (B) containing the same as a main component
And a film substantially composed of a resin composition consisting of polyarylate and polyarylate, wherein the content of polyarylate is 5 to 40% by weight and the degree of plane orientation of the film is 0.0
8 to 0.16, and the thermal characteristics of the film are as follows:
And (b). A film for laminating a metal plate, characterized by satisfying (b). (A) Two or more melting points derived from the resin composition exist only in the range of 200 to 250 ° C. (B) Sum of heats of fusion derived from crystal parts of the resin composition [Δ
Hm] is 25 to 45 J / g. (2) At least a part of the polyester (A) and the polyarylate are melt-mixed in advance, and the remaining polyester (A) and the polyester (B) are mixed using an extruder equipped with a T die, Melting at a temperature of 230-280 ° C,
After being extruded into a sheet form from a T-die, brought into close contact with a casting roll, and quenched, the unstretched sheet was gripped at both ends, preheated at a temperature of 40 to 110 ° C, and then heated at a temperature of 50 to 13 ° C.
At a stretching ratio of 2 to 4 times at 0 ° C.
2. The method for producing a film for laminating a metal plate according to the above 1, wherein the film is heat-set at 80 to 220 ° C. after the axial stretching.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The polyester (A) used in the present invention is obtained by a melt polycondensation reaction or a solid phase polymerization of a terephthalic acid component and an ethylene glycol component as main components, and has an intrinsic viscosity of 0.50 to 0.50. 0.
It is preferably 90 dl / g, more preferably 0.55 to 0.80 dl / g. When the intrinsic viscosity is less than 0.50 dl / g, it is difficult to obtain a film having mechanical strength that can be practically used, and the intrinsic viscosity is 0.90 dl / g.
If it exceeds g, the thermocompression bonding of the film to the metal plate may be impaired.

As the polyester (A), other components may be appropriately copolymerized as long as the effects of the present invention are not impaired. Examples of the acid component as a copolymerization component include aromatic dicarboxylic acids such as isophthalic acid, (phthalic anhydride), 2,6-naphthalenedicarboxylic acid, and 5-sodium sulfoisophthalic acid, oxalic acid, succinic acid, adipic acid, and sebacine. Acid, azelaic acid, dodecanedicarboxylic acid, carbon number 20
~ 60 dimer acids, (anhydride) maleic acid, fumaric acid,
Aliphatic dicarboxylic acids such as itaconic acid, citraconic acid and mesaconic acid; alicyclic dicarboxylic acids such as (anhydrous) hexahydrophthalic acid and hexahydroterephthalic acid; p-hydroxybenzoic acid; lactic acid; β-hydroxybutyric acid; Examples thereof include hydroxycarboxylic acids such as caprolactone, and polyfunctional carboxylic acids such as trimellitic acid (anhydride), trimesic acid, and pyromellitic acid (anhydride).

The alcohol component as a copolymer component includes diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, Aliphatic diols such as 1,6-hexanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, 1,4-
Alicyclic diols such as cyclohexanediethanol, aromatic diols such as ethylene oxide or propylene oxide adducts of bisphenol A and bisphenol S,
Examples include polyfunctional alcohols such as trimethylolpropane, glycerin, and pentaerythritol.

Known methods can be applied as a method for producing the polyester (A). For example, a slurry of terephthalic acid, ethylene glycol and, if necessary, other copolymerization components is continuously supplied to an esterification reactor in which bis (β-hydroxyethyl) terephthalate and a low polymer thereof are present. The reaction is carried out at a temperature of about 3 to 8 hours to continuously obtain an esterified product having an esterification reaction rate of about 95%. Next, this was transferred to a polymerization vessel, and in the presence of a catalyst such as germanium dioxide and antimony trioxide,
The melt polycondensation reaction may be performed at a temperature of 250 to 280 ° C. under a reduced pressure of 1.3 hPa or less until a polyester having a desired intrinsic viscosity is obtained.

The polyester (B) in the present invention is obtained by a melt polycondensation reaction or a solid phase polymerization of a terephthalic acid component and a 1,4-butanediol component as main components, and has an intrinsic viscosity of 0.1. 60 to 2.0 dl /
g, and more preferably 0.80 to 1.6 dl / g. When the intrinsic viscosity is less than 0.60 dl / g, it is difficult to obtain a film having mechanical strength that can be practically used, and when it exceeds 2.0 dl / g, the thermocompression bonding property of the film may be impaired. . Further, as the polyester (B), other components similar to the above-mentioned polyester (A) may be copolymerized as long as the effects of the present invention are not impaired.

Known methods can be applied as a method for producing the polyester (B). For example, dimethyl terephthalate, 1,4-butanediol and, if necessary, other copolymerization components are charged into a transesterification reaction tank and reacted at a temperature of 230 ° C. for about 5 hours to obtain an ester exchange reaction rate of about 95%. Obtain the compound. Next, this was transferred to a polymerization vessel, and 1.3 hP was added in the presence of a catalyst such as tetra-n-butyl titanate or tetraisopropyl titanate.
The melt polycondensation reaction may proceed at a temperature of 220 to 250 ° C. under a reduced pressure of a or less until a polyester having a desired intrinsic viscosity is obtained.

The polyarylate in the present invention is a resin composed of an aromatic dicarboxylic acid component and a dihydric phenol component, and has a number average molecular weight of 7,7 as determined by GPC analysis (effluent: tetrahydrofuran, converted to polystyrene).
It is not less than 000, preferably not less than 10,000. When the molecular weight is less than 7,000, even a film having a low polyarylate content may not exhibit sufficient mechanical properties.

The aromatic dicarboxylic acid component constituting the polyarylate includes terephthalic acid, isophthalic acid, phthalic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid,
Tert-butyl isophthalic acid can be exemplified. Examples of the dihydric phenol component include hydroquinone, resorcinol, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfide, and bis (4 -Hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) -p-diisopropylbenzene, bis (3,5-dimethyl-4-hydroxyphenyl) Methane, bis (3-methyl-4-hydroxyphenyl) methane, bis (3,5-dimethyl-
4-hydroxyphenyl) ether, bis (3,5-dimethyl-4-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4-hydroxyphenyl) sulfide, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, , 2-bis (4-
Hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2-
Bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-
Hydroxyphenyl) propane, 2,2-bis (3-bromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 1,1,1,3,3 , 3-hexafluoro-2,
2-bis (4-hydroxyphenyl) propane, 4,
4'-dihydroxylbiphenyl, 3,3 ', 5,5'
-Tetramethyl-4,4'-dihydroxybiphenyl,
4,4'-dihydroxybenzophenone and the like can be exemplified.

In particular, a polyarylate substantially composed of terephthalic acid and isophthalic acid and 2,2-bis (4-hydroxyphenyl) propane is well known as a so-called engineering plastic having excellent heat resistance and mechanical properties. The use of this resin is also a particularly preferred embodiment in the present invention because the resin is industrially produced.

The polyarylate can be produced by the following method. For example, in the interfacial polymerization method, in the presence of a polymerization catalyst, in a dihydric phenol compound or an aqueous alkali solution in which the dihydric phenol compound is dissolved, dissolved in a solvent that is inert to the reaction and that dissolves the formed resin. A polyarylate can be obtained by mixing an acid halide of an aromatic dicarboxylic acid and reacting the mixture at 2 to 50 ° C for 0.5 to 5 hours.

In the solution polymerization method, a dihydric phenol compound is dissolved in a solvent which is inert to the reaction and dissolves the resin to be formed, in the presence of an acid scavenger such as an organic base or an inorganic base, and is used as a solvent. A polyarylate can be obtained by adding an acid halide of an aromatic dicarboxylic acid and reacting at a temperature of from 5 ° C. to the boiling point of the solvent for at least 0.5 to 5 hours. Polyarylate can also be produced by a melt polymerization method. For example, there is a method of reacting a bisphenol with a diphenyl ester of an aromatic dicarboxylic acid, and a method of reacting an acetyl ester of a bisphenol with an aromatic dicarboxylic acid.

In the present invention, the compounding ratio of the resin composition constituting the film must be such that the content of the polyarylate is 5 to 40% by weight based on the whole resin composition.
When the content of the polyarylate is less than 5% by weight, the effect of adding the polyarylate is not exhibited, and the thermocompression bonding at low temperatures and the impact resistance of the laminated can are not sufficiently improved. On the other hand, when the content of polyarylate exceeds 40% by weight,
Since the oriented crystallization of the film does not proceed sufficiently, there is a problem that the operability during the production of the film is impaired. The content of polyarylate is 5 to 35% by weight, and further 8 to 3% by weight.
0% by weight is preferred.

Polyester (A) and polyester (B)
Is not particularly limited, but the weight ratio is 70/30 to 10/90, and more preferably 60/40 to 10 /.
90 is particularly preferred. If the mixing ratio of the polyester (A) exceeds 70 parts by weight, the resulting film may have poor retort resistance and may be whitened. On the other hand, if it is less than 10 parts by weight, the thermocompression bonding property of the film may be poor.

The film of the present invention has a degree of plane orientation f of 0.0
8 to 0.16. Here, f is defined by the following equation. f = {(nx + ny) / 2} -nz where nx and ny are the maximum and minimum values of the refractive index in the plane direction of the film, and nz represents the refractive index in the thickness direction of the film. When the degree of plane orientation is less than 0.08, the mechanical properties and heat resistance of the film are not sufficient, and when it exceeds 0.16, the thermocompression bonding property of the film may be inferior. In addition, there arises a problem that a micro-crack is generated or broken in the film during processing of the laminated metal plate such as drawing or neck processing.

In the present invention, the differential scanning calorific value (DS)
C) It is necessary that the thermal characteristics of the film obtained by the analysis satisfy the following conditions. (A) There are two or more melting points derived from the resin composition only in the range of 200 to 250 ° C. (B) Sum of heats of fusion derived from crystal parts of the resin composition [Δ
Hm] is 25 to 45 J / g.

The three main components constituting the above-mentioned film, that is, the polyesters (A) and (B), which are crystalline resins, and the polyarylate, which is an amorphous resin, are partially compatible with each other by a transesterification reaction. If the melting point of the polyester resin composition becomes one due to excessive progression of compatibilization, or the melting point disappears, the progress of orientation crystallization slows down, causing a problem in operability during film production, Since the obtained stretched film has a low crystallinity, it may be inferior in flavor properties or the film may be whitened during retort treatment, which is not preferable. Further, even when two or more melting points derived from the resin composition are recognized, the melting point is 200 ° C.
When the amount is less than 1, it is considered that the polyester (A) or (B) which is a crystalline resin is excessively copolymerized, and the obtained film does not have sufficient heat resistance, and the retort resistance and Flavor properties may be poor. Further, when the melting point is in the range of more than 250 ° C., the compatibilization is insufficient, the thermocompression bonding property of the film, the adhesion to the metal plate, and the processability are deteriorated. When the film is stretched, the film is easily broken.

Further, the film of the present invention comprises a sum of heats of fusion [Δ] derived from crystal parts of polyesters (A) and (B).
Hm] is 25 to 45 J / g, more preferably 28 to 4 J / g.
It needs to be 0 J / g. [ΔHm] is 25J
If it is less than / g, the flavor property may be impaired, and if it exceeds 45 J / g, the thermocompression bonding property of the film and the adhesiveness with the metal plate are reduced, and when the laminated metal plate is processed into a can body, Micro cracks occur in the film,
The film and metal may peel off.

The film for laminating a metal plate of the present invention can be produced by a known method such as a flat type or tubular type film forming method. In order to produce a film having less thickness unevenness, a flat type is preferable, and as a stretching method, a sequential biaxial or simultaneous biaxial stretching method is preferable.

In producing the film of the present invention, the polyesters (A) and (B) and the polyarylate must be appropriately compatibilized. Molding of polyarylate generally requires 300 ° C. or higher, but when the resin composition of the present invention is melted and molded at 300 ° C. or higher, the polyester (B) may be thermally decomposed. In order to prevent such thermal decomposition, at least a part of the polyester (A) having excellent thermal stability and polyarylate are melt-mixed to lower the molding temperature, and then the remaining polyester resin composition is melted. It is preferred to mix to produce a film. For example, a polyester (A) and a polyarylate are mixed with a single screw or twin screw extruder to form 280 to
The resin composition obtained by melt-mixing at 350 ° C. to promote the compatibilization of the two, and adding the remaining polyester (A) and polyester (B) to the obtained resin composition, using an extruder equipped with a T-die. The mixture is melt-mixed at a temperature of 230 to 280 ° C., extruded into a sheet from a T-die, and closely adhered to a casting roll whose temperature is controlled to 40 ° C. or lower, and rapidly cooled to obtain an unstretched sheet having a desired thickness. it can. In order to promote the compatibilization of the raw material resin composition, the resin composition obtained by melt-mixing all of the polyarylate and at least a part of the polyester (A), and the remaining polyester (A) and A raw material in which the polyester (B) is melt-mixed in advance may be used, or a catalyst or the like that promotes a transesterification reaction during melt-mixing may be added.

Next, the unstretched sheet is gripped at both ends with clips, and is preheated by blowing hot air at 40 to 110 ° C. from the upper and lower surfaces of the sheet. It is biaxially stretched about twice. Thereafter, the relaxation rate in the vertical and / or horizontal direction is set to several percent, and
After heat-treating the film by heat treatment at 0 ° C. for several seconds, the film is heat-set, cooled to room temperature, and wound at a speed of 20 to 300 m / min to obtain a film having a desired thickness. If the preheating temperature is less than 40 ° C. or the stretching temperature is less than 50 ° C., the stretching stress becomes high, necking occurs, and a stable film cannot be produced or a uniform film cannot be obtained. On the other hand, if the preheating temperature exceeds 110 ° C.
If the temperature exceeds ℃, the film is melted or the crystallization of the film proceeds to whiten, and the degree of plane orientation of the film decreases. When the heat setting temperature is lower than 80 ° C., the heat shrinkage of the obtained film increases, and when it exceeds 220 ° C., the obtained film has a [ΔHm] of more than 45 J / g and is thermocompression-bonded to a metal plate. The performance such as the property may be reduced.

As a heat treatment method after the stretching, known methods can be adopted, for example, a method of blowing hot air to the stretched film, a method of irradiating the stretched film with infrared rays, a method of irradiating the stretched film with microwaves, and the like. However, a method in which hot air is blown onto the stretched film is preferable because heating can be performed uniformly and accurately. Further, as disclosed in JP-B-35-11774, JP-B-43-5557, etc., a heat buffer zone may be provided between the stretching step and the heat fixing step.

The film of the present invention has an average particle diameter of one or more selected from inorganic lubricants such as silica, alumina, kaolin, calcium carbonate, titanium dioxide and barium sulfate, or organic lubricants such as silicone particles. 2.
A required amount of a lubricant of 5 μm or less can be added to impart a slip property to the film surface, thereby improving the processability during film production and thermocompression bonding with a metal plate. In addition, calcium carbonate, titanium dioxide, barium sulfate, etc. are added in a large amount (usually, 10 to 30%) to impart concealing properties and improve the appearance of the metal can body or the printability on the metal can body. . In addition, colorants, antioxidants,
An antistatic agent, a flame retardant and the like can be contained.

The film of the present invention has a thickness of 5 to 100 μm.
m, preferably 10 to 50 μm, more preferably 10
２５25 μm. If the thickness is less than 5 μm, breakage or the like is likely to occur during processing, and if it exceeds 100 μm, the quality becomes excessive and uneconomical.

Further, the film of the present invention has the following properties for the purpose of further improving the thermocompression bonding property with a metal plate and the subsequent adhesion.
The adhesive layer can be provided by a coextrusion method, a lamination process, or a coating process. The dry thickness of the adhesive layer is preferably 0.5 μm or less. In addition, on the opposite side of the film that is thermocompression-bonded to the metal plate, one or two or more resins are used to improve the appearance and printability of the metal can body, and to improve the heat resistance and retort resistance of the film. Layers can be provided. These layers can be provided by a coextrusion method, a lamination or a coating process.

As a method of laminating the film and the metal plate of the present invention, the metal plate is preheated to a predetermined temperature in advance, and the film and the film are pressed against each other by a temperature-controllable roll and thermocompressed. It is manufactured continuously by cooling to below. Examples of the method of heating the metal plate include a heater roll heat transfer method, an induction heating method, a resistance heating method, and a hot air transfer method. preferable. As a cooling method after lamination, a method of dipping in a coolant such as water or a method of contacting with a cooling roll can be used.

As a metal plate suitable for manufacturing a laminated metal plate by laminating the film of the present invention, a sheet-shaped or band-shaped steel plate and an aluminum plate, or a surface of which has been subjected to various plating treatments or chemical conversion treatments. Can be exemplified. In particular, those having a chromium hydrated oxide film on the surface layer have excellent adhesion to the film. In particular, tin-free steel (TFS) having a two-layer structure of a lower layer of metal chromium and an upper layer of chromium hydrated oxide is preferable, and one or more kinds of multi-layer plating of tin, nickel, zinc, aluminum and the like on the surface of the steel sheet. , Alloy plating, and a film having the above two-layer structure or a chromium hydrated oxide film formed on the upper layer.Aluminum is subjected to electrolytic chromic acid treatment, immersion chromic acid treatment, etc. Those having a hydrated oxide film formed thereon can be used.

By using the laminated metal plate obtained as described above, it is excellent in heat resistance, can be subjected to high temperature treatment such as retort treatment, and can perform pinholes, micro cracks, films even when subjected to severe processing. Defects such as peeling of the metal can hardly occur, and a metal can body having excellent flavor properties and impact resistance can be manufactured. The metal can body includes a metal container that has been processed to a form that can be used after being filled with food and drink, and a part thereof, for example, a can lid formed into a shape that can be wound and tightened. It is.
In particular, three-piece cans (3
When used as a can body member of a (P can) or a two-piece can (2P can) manufactured by drawing and ironing, excellent workability of the film and the laminated metal plate of the present invention is exhibited. Also, particularly when a can body having a body height of 10 cm or more is produced by drawing only without substantially ironing as shown in JP-A-3-57514 and JP-A-3-101930. It is suitable. The metal can using the film of the present invention is suitable for filling contents such as coffee, green tea, and black tea because of its excellent retort resistance and flavor.

[0041]

According to the present invention, by adding a polyarylate in addition to the polyester (A) and the polyester (B), the thermocompression bonding property of the film at a low temperature, the workability of a laminated metal plate, and the impact resistance of a metal can body. Is particularly improved, but it is understood that the addition of the polyarylate contributes to the improvement in the adhesiveness of the film to the metal plate and the toughness inherent to the polyarylate. By blending the third component called polyarylate, the compatibility of the polyester (A) and the polyester (B), which were originally incompatible with each other, is facilitated, and as a result,
It is understood that the film has a uniform structure even at a micro level, and that micro cracks and the like hardly occur in the film even under severe processing and impact. In addition, the film of the present invention has been found to have improved flavor, but this is because when polyarylate is produced by interfacial polymerization or solution polymerization, it is possible to obtain a resin from which low molecular weight substances have been removed, It is considered that the glass transition temperature, which is a characteristic of polyarylate, is very high, so that the glass transition temperature of the film also increases.

Next, the present invention will be described more specifically with reference to examples. In addition, the measuring method of each characteristic value used for the Example and the comparative example, and the polyester resin raw material are as follows.

1. Measurement method Intrinsic viscosity [η] of resin: phenol / 1,1,2,2-
The measurement was carried out at 20 ° C. using an equal weight mixed solvent of tetrachloroethane. The unit is dl / g.

Surface orientation degree f of film: manufactured by Atago Optical Co., Ltd.
Using the Abbe refractometer, it was determined by the following equation. f = {(nx + ny) / 2} -nz where nx and ny are the maximum and minimum values of the refractive index in the plane direction of the film, and nz represents the refractive index in the thickness direction of the film. The refractive index is a value obtained by attaching a polarizing plate analyzer to the eyepiece side of an Abbe refractometer and measuring the temperature with a monochromatic NaD line using methylene iodide as a mounting solution at a temperature of 25 ° C. The width of the film used for the measurement was 20
cm, 3 cm from the center and both ends of the film were measured, and the average value was defined as the degree of plane orientation.

Thermal properties of film: 10 to 1 compared to film
A 2 mg sample was collected, and DSC-
7 at 25 ° C. under the condition of a heating rate of 20 ° C./min.
From 300 to 300 ° C. for measurement. In addition, melting | fusing point derived from polyester (A) and (B) was made into the peak top temperature of each melting peak. The heat of fusion [ΔHm] derived from the crystal part of the resin composition is calculated by taking into consideration the endothermic or exothermic peak derived from the heat setting treatment of the film and removing the heat of fusion due to crystallization during the measurement. did.

Film tensile strength: ASTM-D882
The measurement was carried out using a test piece having a width of 10 mm and a length of 10 cm according to the above. The film was measured using 10 test pieces each taken in the machine direction (MD) and in the direction perpendicular to the film (TD), and expressed as an average value.

Laminability: The condition after lamination was visually evaluated according to the following criteria. ：: 98% of the entire area where the film laminated with metal has no defects such as scratches and wrinkles, and is well thermocompressed.
that's all. ：: The above portion is 80% or more of the entire area. Δ: The above portion is 50% or more of the entire area. ×: The above portion is less than 50% of the entire area.

Adhesion: The above-mentioned laminating property is ◎ or ○
From the laminated metal plate judged to be 18 mm wide strip-shaped test piece (the end of the laminated metal plate is not laminated,
(So that the laminated portion is secured at least 8 cm). Next, on the film surface of this test piece,
Adhere the adhesive tape specified in JIS Z-1522 and use an autograph manufactured by Shimadzu Corporation at 10 mm / nin.
A 180 ° peel test was carried out at the following speed, and the peel strength was measured to evaluate the adhesion according to the following criteria. ：: Peel strength of 10 or more test specimens out of 11 specimens was 30
The film was broken at 0 gf or more or 300 gf or more. Δ: Peeling strength of 5 or more test specimens out of 11 specimens was 300
The film was broken at gf or more or 300 gf or more. X: 7 or more test pieces having a peel strength of less than 300 gf.

Moldability-1: After forming a can using a laminated metal plate, the film was inspected visually for damage such as peeling, cutting, cracking and the like by a fluorescence microscope (magnification: 80 times). Was evaluated according to ：: 95 or more of the 100 cans were not damaged. Δ: 80 to 94 out of 100 cans were not damaged. ×: Some damage was observed in 21 or more out of 100 cans.

Formability-2: For each of the metal cans whose moldability was evaluated as ○, 10 cans were filled with a 3% by weight saline solution, sealed, and heated at 80 ° C. for 48 hours. After storage at 50 ° C. for one week, the container was opened and the state of rust generation in the container was evaluated according to the following criteria. ：: Almost no rust was observed. Δ: Rust was generated on less than 5% of the surface area of the film that was in contact with the saline solution. ×: Rust occurred on 5% or more of the surface area of the film that had been in contact with the saline solution.

Retort resistance: A metal can was put in an autoclave (manufactured by Tommy Seiko Co., Ltd., BS-325) and subjected to a retort treatment in steam at 125 ° C. for 30 minutes, and the appearance of the film was whitened and water spots (white spots) were observed. ) And white powder (derived from the oligomers in the film) were visually observed and used as an index of retort resistance. ：: good. Δ: Some change was observed in less than 5% of the film surface area. X: Some change was observed in 5% or more of the film surface area.

Impact resistance: A metal can body was filled with 3% by weight of a saline solution, and a commercially available aluminum EO lid having a diameter of 206 or 202 was rolled up and sealed, and 50 cans were sealed from a height of 50 cm. The can body was dropped on the PVC tile floor so as to collide with the floor. Next, after heating at 80 ° C. for 48 hours, 50
The container was stored for 1 week at ℃, opened, and the occurrence of rust in the can was evaluated in the same manner as in Moldability-2.

Flavor properties: Distilled water was filled in a metal can body, and a commercially available aluminum EO lid having a diameter of 206 or 202 was wound and sealed, and retort treatment was performed in the same manner as described above. Next, after sufficiently cooling to room temperature, the contents were tasted by 100 panelists, and whether or not the odor, taste, etc. were different from distilled water was determined, and the results were flavored according to the following criteria. The index was used. In addition, it was previously confirmed that the aluminum EO lid had no adverse effect on the taste test. ：: Less than 10 people sensed the difference between the two. Δ: The number of persons who sense the difference between the two is 10 or more and less than 30. ×: The number of people who sensed the difference between the two was 30 or more.

2. Raw material resin Polyester (A) Resin A: PET subjected to solid-state polymerization, [η] 0.79 dl
/ G, Tm 256 ° C. Resin B: PET subjected to solid-state polymerization, [η] 0.67 dl
/ G, Tm 256 ° C. Resin C: Isophthalic acid (IPA) 8 mol% copolymerized PE
T, [η] 0.76 dl / g, Tm 236 ° C., not subjected to solid-state polymerization. Resin D: IPA 20 mol% copolymerized PET, [η] 0.
76 dl / g, Tm not observed. Not subjected to solid-state polymerization. Resin E: PET without solid phase polymerization, [η] 0.6
6 dl / g, Tm 255 ° C. However, the average particle size is 1.1 μm
0.1% by weight of silica. Polyester (B) Resin F: Novadur 5009AS, manufactured by Mitsubishi Engineering-Plastics Co., Ltd. Resin G: Novadour 5010S, manufactured by Mitsubishi Engineering-Plastics Co., Ltd. Resin H: IPA 5 mol% copolymerized PBT, [η] 0.9
8 dl / g, Tm216 ° C, solid phase polymerized. Polyarylate resin I: a colorless and transparent resin in which the aromatic dicarboxylic acid component is composed of terephthalic acid (TPA) and IPA in an equimolar ratio, and the divalent phenol component is 2,2-bis (4-hydroxyphenyl) propane Was obtained by an interfacial polymerization method. As a result of the analysis, the number average molecular weight was 15,000 (GPC analysis,
Polystyrene equivalent), glass transition temperature (Tg) is 189
° C. Resin J: Aromatic dicarboxylic acid component having an equimolar ratio of TPA
And a colorless and transparent resin comprising a dihydric phenol component comprising 2,2-bis (3-methyl-4-hydroxyphenyl) propane by IPA. As a result of the analysis, the number average molecular weight was 16,000 (GPC analysis, polystyrene conversion), and Tg was 180 ° C. Melt-mixed resin Resin K: 70 parts by weight of polyester resin A and 30 parts by weight of polyarylate resin I are dry-blended, and a twin-screw extruder equipped with a vent (PCM-45, manufactured by Ikegai Ironworks Co., Ltd., 290) is used. The mixture was melted and kneaded under a reduced pressure of 1 hPa at a temperature of 1 ° C., extruded into a strand (discharge amount: 500 g / min), cooled with water, and then pelletized. After the obtained pellets were sufficiently dried, analysis was carried out. As a result, Tm was 232 ° C. and Tg was 9
5 ° C. Resin L: dry blending of 40 parts by weight of polyester resin A and 60 parts by weight of polyarylate resin I, and resin K
Resin L was obtained by the same operation as described above. As a result of analysis, no Tm was observed, and Tg was 124 ° C. Resin M: 40 parts by weight of polyester resin A and 60 parts by weight of polyarylate resin J are dry-blended, and resin K
Resin M was obtained by the same operation as described above. As a result of analysis, no Tm was observed, and Tg was 116 ° C. Resin N: dry blending of 40 parts by weight of polyester resin C and 60 parts by weight of polyarylate resin I
Resin N was obtained by the same operation as described above. As a result of analysis, no Tm was observed, and Tg was 120 ° C. Resin O: dry blending of 40 parts by weight of polyester resin D and 60 parts by weight of polyarylate resin I
Resin O was obtained by the same operation as described above. As a result of analysis, no Tm was observed, and Tg was 116 ° C.

Example 1 (Production of a film) 3.3 parts by weight of a polyester resin E, 80 parts by weight of a polyester resin F and 16.7 parts by weight of a molten mixed resin L were dry-blended, and this was mixed with a T-die. It was extruded into a sheet at 265 ° C. at a discharge rate of 500 g / min using a provided extruder (slow compression type single screw having a diameter of 75 mm and L / D = 45). Subsequently, this was brought into close contact with a casting roll adjusted to a surface temperature of 18 ° C. and rapidly cooled to obtain an unstretched sheet having a thickness of 200 μm. The end of the unstretched sheet is gripped by a clip of a tenter-type simultaneous biaxial stretching machine, and after traveling in a preheating zone of 60 ° C., it is 3.0 times MD and T at a temperature of 80 ° C.
D was simultaneously biaxially stretched at 3.5 times magnification. Next, after heat-setting at 160 ° C. with a TD relaxation rate of 5%, the film is cooled to room temperature and wound up at a speed of 50 m / min to a thickness of 2 mm.
A 0 μm film was obtained. The obtained film was slit to obtain a roll-shaped film a having a width of 20 cm. next,
Various characteristics were evaluated using this film. Table 1 shows the obtained results.

Example 2 7 parts by weight of a polyester resin E, 25 parts by weight of a polyester resin F and 68 parts by weight of a melt-mixed resin L were dry-blended, and extruded with a T-die in the same manner as in Example 1. 270 ° C, discharge rate 500g / mi
and extruded in a sheet shape with n. Subsequently, this was changed to surface temperature 1
The sheet was closely contacted on a casting roll adjusted to 8 ° C. and rapidly cooled to obtain a 200 μm-thick unstretched sheet. After running the unstretched sheet in a preheating zone at 60 ° C., MD stretching is performed 3.0 times at 80 ° C. between rolls having different peripheral speeds, and then the end of the film is clipped by a tenter-type stretching machine. After running in a preheating zone at 70 ° C., the film was stretched at a temperature of 95 ° C. to a TD at a magnification of 3.5 times. Next, after heat-setting at 160 ° C. with a TD relaxation rate of 5%, the film was cooled to room temperature and wound up at a speed of 50 m / min to obtain a film having a thickness of 20 μm. The obtained film was slit to obtain a roll-shaped film b having a width of 20 cm. Next, various characteristics were evaluated using this film. Table 1 shows the obtained results.

Examples 3 to 9 and Comparative Examples 1 to 5 The raw material resins, the compounding ratios and the film production conditions were changed as shown in Tables 1 and 2, and various kinds of resins were prepared in the same manner as in Example 1 or Example 2. A film was obtained. The performance of the obtained film is shown in Tables 1 and 2.

Comparative Example 6 90 parts by weight of polyester resin G and polyarylate I
Was dry blended at 280 ° C. in the same manner as in Example 1, and a flow mark (irregular flow pattern) was generated on the unstretched sheet. Therefore, the extrusion temperature was increased to 290 ° C., but was not eliminated. When the extrusion temperature was further raised to 300 ° C., a gas was generated that was considered to be due to thermal decomposition of the polyester resin G, and pinholes were generated in the unstretched sheet.

Comparative Example 7 5 parts by weight of the polyester resin E, 25 parts by weight of the polyester resin F and 70 parts by weight of the molten resin L were dry-blended and extruded at 280 ° C. in the same manner as in Example 1, An unstretched sheet of 200 μm was obtained. Then, the end of the unstretched sheet is gripped by a clip of a tenter type simultaneous biaxial stretching machine, and after traveling in a preheating zone of 60 ° C., it is 3.0 times in MD and 3.0 in TD at a temperature of 80 ° C. Simultaneous biaxial stretching was attempted at a stretching ratio of 5 times, but breakage occurred frequently. Therefore, the preheating and stretching temperature were increased to find the optimum conditions, but the film was easily melted at a high temperature, and the film could not be manufactured stably.

Comparative Example 8 60 parts by weight of polyester resin A, polyester resin G
Was dry-blended with 30 parts by weight of polyarylate I and 10 parts by weight of polyarylate I, and the mixture was subjected to 280 with a twin-screw extruder equipped with a vent.
The mixture was melted and kneaded at a reduced pressure of 1 hPa at a temperature of 1 h, extruded into a strand (a discharge amount of 350 g / min), cooled with water, and then pelletized. After sufficiently drying the obtained pellet, a film o having a thickness of 20 μm was obtained in the same manner as in Example 1.
Table 2 shows the performance of the obtained film. Since the obtained film was excessively melt-kneaded, the resin composition was excessively compatible and had a single melting point, and the heat of fusion [ΔHm] was low.

[0061]

[Table 1]

[0062]

[Table 2]

Example 10 (Manufacture of laminated metal plate and metal can body) A tin-plated roll-shaped tin plate having a thickness of 0.19 mm and a width of 22 cm was heated to 180 ° C. by an induction heating roll. A roll-shaped film a having a width of 20 cm obtained in Example 1
Was laminated at a line speed of 20 m / min using a pair of silicone rolls adjusted to a surface temperature of 50 ° C., and then immersed and cooled in ice water after 2 seconds to obtain a laminated metal plate. After 2 seconds of immersion in ice water, it was confirmed that the laminated metal plate was cooled to 20 ° C. or lower. After cutting into a body blank using the obtained laminated metal plate, it is formed into a cylindrical shape by a roll former, subjected to welding, neck-in processing, trimming, and tightened using a commercially available steel 206-diameter lid, 211 diameter welding can (outer diameter 67mm, body height 100m
m). Table 3 shows the evaluation results of the performance of the obtained laminated metal plate and metal can.

Examples 11 to 14 and Comparative Examples 9 to 11 As shown in Table 3, a laminated metal plate and a metal can were manufactured in the same manner as in Example 10 except that the film was changed. Table 3 shows the performance of the obtained laminated metal plate and metal can body.

[0065]

[Table 3]

Example 15 Tin-free steel (TFS, temper degree T-4) in the form of a roll having a thickness of 0.24 mm and a width of 22 cm was heated to 210 ° C. by means of a heater-heating roll. The obtained roll-shaped film c having a width of 20 cm was laminated using a pair of silicone rolls adjusted to a surface temperature of 50 ° C. at a line speed of 20 m / min, and then immersed and cooled in ice water after 2.5 sec. Thus, a laminated metal plate was obtained. After 2 seconds of immersion in ice water, it was confirmed that the laminated metal plate was cooled to 20 ° C. or lower. Using the obtained laminated metal plate,
After performing drawing and ironing under the following molding conditions, neck-in processing and trimming are performed to obtain a 202P 2P can (outside diameter 53 m).
m, body height 100 mm). Blank diameter: 139 mm Drawing condition: first drawing ratio 1.85, second drawing ratio 1.42 Ironing punch diameter: 52.65 mm Total ironing rate: 35% The performance of the obtained laminated metal plate and metal can body Table 4 shows the evaluation results.

Example 16 In the same manner as in Example 15, except that rolled aluminum (3004H19 material, plate thickness 0.24 mm, plate width 22 cm, phosphoric acid-chromate chemical conversion product) was used as the metal plate. A laminated metal plate and a metal can were obtained. Table 4 shows the evaluation results of the performance of the obtained laminated metal plate and metal can.

Examples 17 to 24 and Comparative Examples 12 to 17 Example 1 was repeated except that the types of film and metal plate and the heating temperature of the metal plate during lamination were changed as shown in Table 4.
In the same manner as in No. 5, a laminated metal plate and a metal can were manufactured. Table 4 shows the evaluation results of the performance of the obtained laminated metal plate and metal can.

Comparative Example 18 Lamination was attempted in the same manner as in Example 15 using Film 1, but the film shrank during lamination, and a good laminated metal plate could not be obtained.

[0070]

[Table 4]

[0071]

According to the present invention, (a) excellent mechanical properties and heat resistance, (a) thermocompression bonding to a metal plate even with a high degree of crystallinity, and thermocompression bonding to a metal plate are possible. The quality of the laminated metal plate is unlikely to change even when the conditions fluctuate, and it is possible to perform thermocompression bonding even at a low temperature of 200 ° C or less.
(C) The laminated metal sheet obtained by laminating this is excellent in workability and formability, and is capable of producing deep-drawn cans and drawn and ironed cans. It is possible to provide a film having excellent properties, retort resistance, impact resistance, and printability. Further, according to the present invention, it is possible to provide a method for easily producing a film of stable quality without causing thermal decomposition of the polyester (B).

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B65D 1/28 C08L 67/02 C08L 67/02 B65D 1/00 B // (C08L 67/02 C 67:02 55:00) B29K 67: 00 B29L 7:00 (72) Inventor Kiyomi Hata 23 Uji Kozakura, Uji-city, Kyoto, Japan, in the Unitika Research Center (72) Inventor Yoshihiro Umemura 23 Uji Kozakura, Uji-shi, Kyoto, 23 In Unitika Research Center, Central Research Institute

Claims (3)

[Claims] 1. Polyethylene terephthalate or a polyester based on the same (A), polybutylene terephthalate or a polyester based on the same (B),
A film substantially composed of a resin composition comprising polyarylate, wherein the content of polyarylate is 5
-40% by weight, and the degree of plane orientation of the film is 0.08-
0.16, wherein the thermal properties of the film satisfy the following (a) and (b): (A) Two or more melting points derived from the resin composition exist only in the range of 200 to 250 ° C. (B) Sum of heats of fusion derived from crystal parts of the resin composition [Δ
Hm] is 25 to 45 J / g. 2. The weight ratio of the polyester (A) to the polyester (B) is 60/40 to 10/90, respectively.
2. The metal plate laminating film according to claim 1, wherein the total weight is 100. 3. A method in which at least a part of the polyester (A) and the polyarylate are melt-mixed in advance, and the remaining polyester (A) and the polyester (B) are mixed with T
Using an extruder equipped with a die, melt at a temperature of 230 to 280 ° C., extrude into a sheet from a T-die, hold on both ends of an unstretched sheet obtained by closely cooling on a casting roll and quenching. After preheating at 40-110 ° C, 5
The film for metal plate lamination according to claim 1, wherein the film is biaxially stretched at a stretching ratio of 2 to 4 times at 0 to 130 ° C. in each of a longitudinal direction and a transverse direction, and then heat-set at 80 to 220 ° C. 4. Manufacturing method.