JP3470526B2 - Production method of double-sided resin-coated metal laminate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a double-sided resin-coated metal laminate material, and more specifically, a thermoplastic resin is coated on both surfaces of a metal base material at the same time.
Further, the present invention relates to an extrusion laminating method for producing a double-sided resin-coated metal laminating material having a thin resin coating and high performance, that is, having uniform thickness, high workability, high adhesion, and high film physical properties at a high speed.

[0002]

2. Description of the Related Art Heretofore, as a means for imparting corrosion resistance to a metal material, it has been widely practiced to coat a metal surface with a resin layer, and as a coating method used in such a technique,
Epoxy resin, phenolic resin, acrylic resin, polyester resin, etc. A thermosetting resin dispersed in a solvent is applied to a metal surface, or a preformed film such as polyester, olefin resin, polyamide There is known a method of laminating a film of a type or the like with a metal base material via an adhesive of an isocyanate type, an epoxy type, a phenol type or the like.

It is also widely known to utilize the heat-sealing property of a thermoplastic resin for bonding a metal substrate and a thermoplastic resin. In this method, a preformed film such as a thermoplastic polyester is used as a metal. There are known a method of adhering to a plate by heat adhesion and a method of adhering a molten thin film of extruded thermoplastic polyester resin or the like to a metal plate.

Japanese Patent Application Laid-Open No. 51-137760 discloses that
A device for coating a synthetic resin on both sides of a sheet of paper, aluminum foil or the like, which is provided with two T dies facing each other and provided with a sheet feeding device for running the sheet between these T dies, A coating apparatus is described which is characterized in that a synthetic resin layer is simultaneously formed on both sides of a sheet by extruding a synthetic resin from two T dies when the sheet is running, and FIGS. 1 and 4 show the coating apparatus. , A synthetic resin is extruded onto a sheet and then passed between chill rolls.

US Pat. No. 5,407,702 describes
A method of coating while extruding a resin on both surfaces of a metal strip is described, and a metal strip such as an aluminum alloy is preliminarily treated with a preconditioner,
It is described to be moved through two extrusion dies, a post-heater, and a cooling system to coat both sides of the strip with a thin coating of polyester material. In the apparatus shown in FIG. 1 of this specification, a thin film of polyester extruded from a die is thinly drawn by a first roll, cooled by a second roll, and turned into a metal strip heated by a third roll. It is described that crimping is performed.

In Japanese Unexamined Patent Publication No. 6-79801, a pressure roll is pressed against a preheated metal plate wound around a winding roll, and a T-die is passed through an extruder through a gap between the pressure roll and the metal plate. The molten thermoplastic resin is flowed down to temporarily coat the thermoplastic resin on the metal plate, and then this resin-coated metal plate is wrapped around another winding roll so that the resin-coated surface is in contact with the winding roll side. Press the other pressure roll from the plate side and press it through the extruder into the gap between the other pressure roll and the metal plate.
Molten thermoplastic resin flows down from the die to temporarily adhere the thermoplastic resin to the other side of the metal plate to obtain a double-sided resin-coated metal plate, then heat the double-sided resin-coated metal plate with a downstream heating device. A method for producing a double-sided resin-coated metal plate is described.

[0007]

However, these known techniques use resin metal laminates in which the resin coating is a thin film and has high performance, that is, thickness uniformity, high workability, high adhesion, and high film physical properties. The purpose of producing at high speed is not yet fully satisfactory.

Although the first technique cited above can be applied to the production of laminates for soft packaging materials typified by pouches, it is not yet applicable to the production of laminate materials for cans.
That is, in the laminate for a soft wrapping material, the metal used is a remarkably thin metal foil for the purpose of imparting gas barrier properties, while the other resin layer imparts heat seal properties and functions as a stress carrier. It is a thick layer that doubles as a double layer. On the other hand, in the laminated material for can manufacturing, the metal serves as a stress carrier and is a source that can withstand various processes such as pressing, deep drawing, bending and stretching, and ironing.
On the other hand, in terms of workability, the resin coating layer is required to be thin in the range in which corrosion resistance, adhesion, and film uniformity are ensured. The above-mentioned first technique is difficult to apply the resin film on the metal surface in a thinned state, and is obviously not suitable for manufacturing a laminate material for can manufacturing.

Although the second and third techniques cited above are recognized as being applicable to the production of laminate materials for can manufacturing, they are still insufficient from the viewpoint of producing high-performance resin-metal laminate materials. I'm not satisfied. That is,
These techniques require an operation of heating a metal plate prior to laminating a resin such as polyester, and an operation of heating a resin-metal laminating material after laminating the resin to complete the fusion. The operation of repeatedly heating a metal plate or a resin-coated metal plate at such a high temperature causes thermal softening of the metal plate and deterioration of the resin due to thermal decomposition (thermal degradation) or thermal oxidation, which deteriorates various properties of the laminate material. It is not preferable because it causes. This decrease in various characteristics becomes more remarkable as the number of heating times increases and generally the thickness of the resin thin film decreases.

Further, in the production of a resin-metal laminate material for can manufacturing, there is a technical problem that a thin resin film must be firmly adhered to a metal plate with a uniform thickness.
For example, in the case of a film that has been biaxially stretched in advance, it may be possible to laminate by heat bonding with a relatively uniform thickness, but it is necessary to form and stretch the film in a separate process, which complicates the process. Become. On the other hand, in the case of extrusion coating of resin, which is the second technique cited above, it is necessary to perform a troublesome operation of cooling and forming a film while stretching the extruded molten resin into a thin film, and at the same time, forming the resin during film formation. There is also a problem that the surface temperature is lowered and it becomes difficult to firmly bond the metal plate with heat. Furthermore, as the film becomes thinner and the speed becomes higher, there is a concern that the resin film may be wrinkled on the third roll.

Therefore, an object of the present invention is to coat both surfaces of a metal material with a thermoplastic resin at the same time, and the resin coating is a thin film and has high performance, that is, uniform thickness, high workability, high adhesion, and high coating. Another object of the present invention is to provide a method for producing a double-sided resin-coated metal laminate material having physical properties and the like at a high speed.

Another object of the present invention is to prevent the heat softening of the metal, the thermal degradation of the resin and the thermal oxidation as much as possible, and, while being a uniform thin film, have a remarkably excellent adhesion to the metal. Another object of the present invention is to provide a method for producing a double-sided resin-coated metal laminate material.

Still another object of the present invention is that the resin metal laminate to be formed can withstand a large degree of working such as deep drawing, bending and stretching, and ironing, and further, after working. The molded body has excellent corrosion resistance,
As a result, it is an object of the present invention to provide a method capable of producing a double-sided resin-coated metal laminate material which is useful for use as a can.

[0014]

According to the present invention, in a method for simultaneously forming a resin coating on both surfaces of a metal substrate,
A heating area of the metal base material along the path of the metal base material, a die for supplying a pair of thermoplastic resins that are made to face each other with respect to the passage of the heated metal base material in a film shape, and a metal base material A pair of warm laminating rolls that adhere thermoplastic resin on both sides,
A quenching means for quenching the formed laminate material is arranged, and a metal base material heated in a direction substantially perpendicular to a line connecting the centers of the warm lamination rolls is passed between the pair of warm lamination rolls, The molten film of the thermoplastic resin from each die is supported and conveyed by the corresponding warm laminating roll and supplied to the nip position between the warm laminating rolls, and the thin film of the thermoplastic resin is simultaneously fused to both sides of the metal base material. A method for producing a double-sided resin-coated metal laminate material is provided.

In the present invention, the molten film of the thermoplastic resin from the die is approximately tangential to the warm laminating roll and the winding angle (θ) around the warm laminating roll is 2 to 45 degrees, and particularly 2 to 30 degrees. It is preferable that the thin film of the thermoplastic resin is introduced onto the warm laminating roll in the range described below and the thin film of the thermoplastic resin is fused on both surfaces of the heated metal substrate by the warm laminating roll.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 showing the arrangement of an apparatus used in the present invention, along a passage 2 of a metal base material 1, a heating zone 3 of the metal base material and a passage 2 of the metal base material are aligned. A pair of dies 5 for supplying the opposed thermoplastic resins 4a, 4b in a film shape.
a, 5b and the thermoplastic resin 4a, 4 on both sides of the metal substrate 1.
a pair of warm laminating rolls 6a, 6b for adhering b
And a quenching means 8 for quenching the formed laminate material 7.
And are placed.

The present invention (1) uses warm laminating rolls 6a and 6b as laminating rolls, (2)
Passing the metal base material 1 between the pair of warm laminating rolls 6a and 6b and in a direction substantially perpendicular to a line connecting the centers of the warm laminating rolls 6a and 6b, and (3)
Molten film 4a, 4b of thermoplastic from dies 5a, 5b
Is supported and conveyed by the corresponding warm laminating rolls 6a and 6b, and is supplied to the nip position 10 between the warm laminating rolls to simultaneously fuse the thermoplastic resin thin film to both surfaces of the metal substrate 1. It is a characteristic.

That is, according to the present invention, in order to prevent the deterioration of the performance due to the excessive heating of the metal base material and the thermoplastic resin, it is indispensable to effectively utilize the heat of each material. The combination of the means (1), (2) and (3) is extremely effective. Further, by combining these means, both sides of the metal material are coated with the thermoplastic resin at the same time, and the resin coating is a thin film and has high performance, that is, thickness uniformity, high workability, high adhesion, high film physical properties, etc. The effect that the double-sided resin-coated metal laminate material having the above is manufactured at high speed is achieved.

Conventionally, a cooled laminate roll has been generally used as a laminate roll used for fusion bonding of a metal base material and a thermoplastic resin, but in the present invention, a warm laminate roll may be used. This is one feature. The term "warm" is a concept that belongs to an intermediate between cold and hot, which is often used, and means a treatment at a temperature higher than room temperature and lower than the melting point of the thermoplastic resin. In the present invention, by performing warm lamination, rapid heat transfer to the resin in contact with the roll is suppressed, and the heat of the heated metal base material and the heat of the melt-extruded resin are effectively heated. It can be used for bonding.

In the manufacturing method of the present invention, the metal base material 1 heated in the heating zone 3 is guided to the nip position of the warm laminating rolls 6a and 6b, but the passage 2 of the metal base material and the warm laminating roll 6a are used. , 6b in the above-mentioned positional relationship is important, whereby the metal base material 1 reaches the nip position 10 of the warm laminating rolls 6a, 6b.
The contact with other members is avoided, and the decrease in the surface temperature of the metal substrate 1 is maintained at the slowest speed corresponding to the cooling rate in the air.

Therefore, in the method of the present invention, the metal substrate 1
The temperature and heat capacity possessed by can be effectively used for heat fusion with the thermoplastic resin thin film, and high adhesive strength can be obtained between the thermoplastic resin 4 and the metal substrate 1 without requiring reheating. be able to. That is, when the metal base material 1 is wound around a warm laminating roll, the contact due to the winding causes a temperature decrease of the metal base material 1 and unless the metal base material 1 is reheated after lamination, Although insufficient contact with the resin layer occurs, this temperature drop is avoided in the present invention.

In the manufacturing method of the present invention, the molten films 4a, 5b of the thermoplastic resin from the dies 5a, 5b are introduced onto the corresponding warm laminating rolls 6a, 6b. At this time, the molten thin films 4a, 4b are formed. It is also important to carry and support the warm laminating rolls 6a and 6b and supply it to the nip position 10.

In FIG. 2 (only one resin is shown as 4 so as not to complicate the drawing) for explaining the method of supplying the thermoplastic resin melt to the laminating roll, the melting of the thermoplastic resin is performed. To supply the product, the molten resin 4 from the die is warm-laminated as in the present invention.
When it is once supported and conveyed by a and supplied to the nip position (referred to as method 1), it is in a direction substantially perpendicular to the line connecting the centers of the warm laminating rolls (Y direction). There is a case (referred to as method 2) to be introduced in the above.

In order to prevent a decrease in the resin temperature due to contact with a roll, the usual extrusion lamination, particularly when the thickness of the resin layer is small (this point is different from the lamination for producing a soft packaging material), Method 1 is generally adopted. However, in this method, it is not possible to heat-bond the thermoplastic resin to both surfaces of the metal base material at the same time, and there is no choice but to perform the bonding one by one on each side, resulting in a long process and a complicated apparatus. There is. In addition, the metal base material or the laminate material must be heated prior to the bonding in each step, and therefore the performance of the metal base material or the thermoplastic resin is unavoidably deteriorated. Further, since the molten film of the thermoplastic resin is directly supplied to the nip position, the supply state is apt to be unstable, and the occurrence of uneven thickness or wrinkles due to corrugation, adhesion failure due to air entrainment and occurrence of coating defects are avoided. In order to reduce this, the laminating speed must be slowed down, and the production speed will be slowed down. Furthermore, since the molten film of the thermoplastic resin suddenly contacts the laminating roll under pressure at the nip position, the resin adheres to and transfers to the roll surface, and the resin layer on the surface of the metal base material tends to have many defects.

On the other hand, in the present invention, as the method of supplying the metal substrate 1, the straight-line method of (2) is adopted, and as the method of supplying the thermoplastic resin molten film, the method of (3) is used.
By adopting the warm roll transfer method of No. 2, it is possible to simultaneously coat the both surfaces of the metal base material with the resin, the number of steps can be reduced, and the apparatus can be remarkably simplified. Further, the heating for heat bonding may be the first heating of the metal base material, and the deterioration of the performance of the metal or resin due to repeated heating can be suppressed. Furthermore, the molten film of thermoplastic resin,
Since the surface opposite to the adhesive surface is supported by the warm roller surface and is supplied to the nip position in this supported state, the supply state at the nip position becomes stable, and uneven thickness or wrinkles due to corrugation is not generated. Without and without causing air entrapment, the coating formed is excellent in defect-free coverage. Therefore, according to the present invention, the laminating speed can be made significantly higher than that of the conventional one, and the productivity can be improved. Furthermore, since the molten film of the thermoplastic resin first comes into contact with the warming laminating roll in a state where the pressure is extremely low, and then is pressed at the nip position, there is no tendency for the resin to adhere and migrate to the roll surface. The resin layer on the surface of the base material has no defects.

In the present invention, the combination of (1) the warm laminating roll method and (3) the roll conveying method of the resin molten film also enhances the adhesiveness of the coating and allows the resin molten film to be sufficiently formed. It is important to stably supply the thin film to the nip position. In this combination scheme of the invention,
It is possible to supply the resin to the nip position with a temperature distribution structure in which the side to be the adhesive surface of the resin is in a sufficiently molten state and only the very surface layer on the opposite side is solidified.

Regarding Method 1 and Method 2, in FIG. 3 showing the relationship between the moving distance from a fixed position in the molten resin passage to the warm laminating roll and the resin temperature on the very surface on the roll contact side, Method 2 (fine line) In the case of (1), the resin surface temperature only decreases at a speed corresponding to the cooling rate in air, reaches the nip start position B when the resin temperature is considerably high, and the nip pressure is increased in this state. receive. For this reason, as already pointed out, roll adhesion of molten resin is likely to occur, and the state of coating of the obtained laminate material is extremely unsatisfactory in terms of completeness of coating, uniform thickness, and smoothness. Becomes

On the other hand, in the method 1, as shown by the thick line in FIG. 3, only the very thin layer on the side in contact with the warm roll at the contact A is slightly cooled (solidified), and then the nip position B is reached. Since the pressure of the nip is applied in, the thermoplastic resin does not adhere to the roll, and it is excellent in terms of the completeness of the coating and the uniformity of the thickness, and also in terms of the smoothness. Also,
In the present invention, since the adhesion to the roll surface is prevented, it is possible to nip at a higher pressure, thereby improving the adhesion between the metal base material and the resin, and preventing air entrapment. .

Further, in the present invention (method 1), the molten resin from the die is supported and conveyed by the warm laminating roll, whereby not only the resin can be stably flown into the nip position but also the die outlet. The melt of the thermoplastic resin can be made sufficiently thin and stable in accordance with the ratio of the extrusion speed from the sheet to the peripheral speed of the warm laminating roll. Also in the case of Method 2, it is possible to reduce the thickness of the melt of the thermoplastic resin in accordance with the ratio of the extrusion speed from the die exit and the peripheral speed of the warm laminating roll, but winding around the roll Since there is no such difference, thinning due to flow stretching becomes unstable, and uneven thickness such as resin pool (bank) is likely to occur. On the other hand, in the present invention, by performing support and conveyance by the warm laminating roll,
Back tension can be applied to the resin, which can eliminate the occurrence of banks.

In the present invention, the molten film 4 of the thermoplastic resin from the die 5 is substantially tangential to the warm laminating roll 6 and the wrapping angle (θ) around the warm laminating roll 6 is 2 to 45 degrees, particularly It is preferable to guide it onto a warm laminating roll in the range of 2 to 30 degrees, and fuse the thin film of the thermoplastic resin to both surfaces of the metal base material by the warm laminating roll.

In the present specification, the winding angle θ around the warm laminating roll is the contact point A between the molten film of the thermoplastic resin and the warm laminating roll 6 in FIG. 2 and the center of the pair of warm laminating rolls. Means the angle (θ) formed with respect to the center of the warm laminating roll.
In both methods 1 and 2, the nip position typically lies across a width N rather than a line.

In the present invention, it is particularly preferable to set the winding angle θ of the resin around the warm laminating roll within the above range. If the winding angle θ is larger than the above range, the temperature of the side of the thermoplastic resin that should come into contact with the metal base material decreases, so that a satisfactory adhesion force with the metal base material cannot be obtained. Become. Further, when the winding angle θ is larger than the above range, the resin layer is bent on the warm laminating roll, and uneven thickness is likely to occur. Figure 4
Is a plot of the relationship between the winding angle of the resin film and the film thickness unevenness, and it can be seen from this that the winding angle must be within a certain range.

On the other hand, when the winding angle θ around the roll is smaller than the range specified in the present invention, the resin is apt to adhere to the roll, and the thinning due to the flow stretching becomes unstable, so that the resin becomes unstable. Thickness unevenness like a bank is likely to occur.

According to the present invention, the resin-metal laminate material discharged from the warm laminating roll is introduced into the quenching means to be rapidly cooled, so that the resin coating has a thin film and high performance, that is, the uniformity of thickness, It becomes a resin-metal laminate material having high processability, high adhesion, and high film physical properties.

That is, according to the present invention, the heat of the metal base material heated to the minimum required temperature can be effectively utilized for thermal bonding, and reheating for fusion bonding is not required. Thermal softening, thermal degradation of resin (thermal decomposition) and thermal oxidation are prevented as much as possible to improve various physical properties of the laminated material, and the formed resin-metal laminated material is deep-drawn and bent and extended. It is possible to provide a resin-metal laminate material for can manufacturing, which can withstand processing and further processing with a large degree of processing such as ironing, and in which the molded product after processing has excellent corrosion resistance. Of course, it is generally not necessary, but the heat softening of the metal,
It should be understood that it is permissible to reheat the laminate material to improve the adhesion within a range that does not substantially cause thermal degradation or thermal oxidation of the resin.

Further, according to the present invention, the temperature of the metal base material, the temperature of the adhesive side resin of the extruded resin, the thinning of the resin and the drawing to the nip position can be smoothly carried out. It has excellent workability and is capable of producing resin-metal laminate materials at high speeds.
Excellent productivity and economy.

[Metallic Material] In the present invention, various surface-treated steel plates, light metal plates such as aluminum, or foils thereof are used as the metal substrate.

As the surface-treated steel sheet, a steel sheet obtained by temper-rolling or secondary cold-rolling after annealing a cold-rolled steel sheet, that is, S
It is possible to use the R material and the DR material that have been subjected to one or more surface treatments such as zinc plating, tin plating, nickel plating, electrolytic chromic acid treatment, and chromic acid treatment. An example of a suitable surface-treated steel sheet is an electrolytic chromic acid-treated steel sheet, particularly a metal chromium layer of 10 to 200 mg / m ² and 1
To 50 mg / m ² (calculated as metallic chromium), which has an excellent combination of coating film adhesion and corrosion resistance. Another example of the surface-treated steel plate is a hard tin plate having a tin plating amount of 0.6 to 11.2 g / m ² . This tin plate is preferably subjected to chromic acid treatment or chromic acid / phosphoric acid treatment so that the amount of chromium becomes 1 to 30 mg / m ^{2 in} terms of metal chromium. As still another example, an aluminum-coated steel plate that has been subjected to aluminum plating, aluminum pressure welding, or the like is used.

As the light metal plate, an aluminum alloy plate is used in addition to the so-called pure aluminum plate. An aluminum alloy plate excellent in corrosion resistance and workability has a Mn: 0.
2 to 1.5% by weight, Mg: 0.8 to 5% by weight, Z
It has a composition of n: 0.25 to 0.3% by weight, Cu: 0.16 to 0.26% by weight, and the balance of Al. These light metal plates are also preferably subjected to chromic acid treatment or chromic acid / phosphoric acid treatment so that the chromium amount becomes 20 to 300 mg / m ^{2 in} terms of metal chromium.

Although the thickness of the metal plate varies depending on the type of metal, the use or size of the laminating material, it is generally preferable that the thickness of the metal plate is 0.10 to 0.50 mm. Is 0.10 to 0.3
The thickness is 0 mm, and in the case of a light metal plate, the thickness is preferably 0.15 to 0.40 mm.

If desired, an adhesive primer may be provided on the metal material, and such a primer exhibits excellent adhesion to both the metal material and the thermoplastic resin. A typical example of a primer coating having excellent adhesion and corrosion resistance is a phenol epoxy-based coating composed of a resol-type phenol aldehyde resin derived from various phenols and formaldehyde, and a bisphenol-type epoxy resin. In particular, a phenol resin and an epoxy resin are mixed in a weight ratio of 50:50 to 5:95, especially 4
It is a paint containing a weight ratio of 0:60 to 10:90. Generally, the adhesive primer layer should have a thickness of 0.3 to 5 μm.

[Thermoplastic Resin] As the thermoplastic resin,
Any material that can be extruded and has a film-forming property, such as low-density polyethylene, high-density polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene or ethylene, pyropyrene, 1-butene, 4- Polyolefin such as random or block copolymers of α-olefins such as methyl-1-pentene, ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, ethylene / vinyl such as ethylene / vinyl chloride copolymer Compound copolymer, polystyrene, acrylonitrile / styrene copolymer, ABS, styrene resin such as α-methylstyrene / styrene copolymer, polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymer, polyacrylic Polyvinylates such as methyl acidate and polymethylmethacrylate Compound, nylon 6, nylon 6-
Polyamide such as 6, nylon 6-10, nylon 11 and nylon 12, thermoplastic polyester such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, polyphenylene oxide and the like, or a mixture thereof may be used. Of course, in the present invention, the resin applied to both surfaces of the metal substrate may be the same or different from each other. For example, as a metal container, a resin suitable for the inner surface side and a resin suitable for the outer surface side. It should be understood that a combination with and can be selected, and the thickness and composition can be appropriately selected.

Thermoplastic resins or copolymerized polyesters, blends thereof, or laminates thereof are particularly preferable as thermoplastic resins in view of film physical properties, processability, and corrosion resistance. Polyesters based on ethylene terephthalate units are particularly suitable.

As the raw material polyester, polyethylene terephthalate itself can be used, but it is desirable from the viewpoint of impact resistance and processability of the laminate to lower the maximum crystallinity that the coating can reach. It is advisable to introduce copolymerized ester units other than ethylene terephthalate therein.

Mainly composed of ethylene terephthalate units,
A melting point of 210 to 252 including a small amount of other ester units
It is particularly preferred to use a copolyester of ° C.
The melting point of homopolyethylene terephthalate is generally 2
It is 55-265 degreeC.

Generally, 70 mol% or more, especially 75 mol% or more of the dibasic acid component in the copolyester is composed of a terephthalic acid component, and 70 mol% or more, particularly 75 mol% or more of the diol component is composed of ethylene glycol, It is preferable that 1 to 30 mol%, particularly 5 to 25% of the dibasic acid component and / or diol component is composed of a dibasic acid component other than terephthalic acid and / or a diol component other than ethylene glycol.

Dibasic acids other than terephthalic acid include aromatic dicarboxylic acids such as isophthalic acid, phthalic acid and naphthalenedicarboxylic acid: alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid: succinic acid, adipic acid, sebacic acid, dodecane. Aliphatic dicarboxylic acids such as dionic acid: One or a combination of two or more thereof may be mentioned. As the diol component other than ethylene glycol, propylene glycol,
1,4-butanediol, diethylene glycol, 1,
One or more of 6-hexylene glycol, cyclohexanedimethanol, and an ethylene oxide adduct of bisphenol A can be used. Of course, the combination of these comonomers must have the melting point of the copolyester within the above range. Further, a polyfunctional monomer such as trimellitic acid, pyromellitic acid, or pentaerythritol can be used in combination.

The polyester used should have a molecular weight sufficient to form a film, for which an intrinsic viscosity (IV) of 0.55 to 1.9 dl / g, in particular 0.65 to 1.4 dl / g.
Those in the range of are desirable.

The thermoplastic resin coating layer contains an inorganic filler (pigment) for the purpose of concealing the metal plate and assisting the transmission of the wrinkle holding force to the metal plate during drawing-redrawing. You can In addition, a compounding agent known per se for the film, for example, an antiblocking agent such as amorphous silica, various antistatic agents, lubricants, antioxidants, ultraviolet absorbers and the like may be added to this film according to a known formulation. it can.

The inorganic fillers include inorganic white pigments such as rutile type or anatase type titanium dioxide, zinc white, and gloss white; barite, precipitated barium sulfate, calcium carbonate, gypsum, precipitated silica, aerosol, talc, calcined or Is a white extender pigment such as unsintered clay, barium carbonate, alumina white, synthetic or natural mica, synthetic calcium silicate, magnesium carbonate; black pigment such as carbon black and magnetite; red pigment such as red iron oxide; yellow pigment such as siena. And blue pigments such as ultramarine blue and cobalt blue. These inorganic fillers can be added in an amount of 10 to 500% by weight, particularly 10 to 300% by weight, based on the resin.

[Manufacturing conditions] In the present invention, the melting point (Tm) of the thermoplastic resin is -80 ° C to Tm + 50.
It is preferable to heat to a temperature of 0 ° C., particularly Tm-50 ° C. to Tm + 30 ° C. (a temperature immediately before entering the warm laminating roll). For heating the metal base material, energization heat generation, high frequency induction heating,
It is possible to use heating means known per se such as infrared heating, hot-air stove heating, and roller heating.

When the heating temperature is lower than the above range, the adhesion is not sufficient, while when it is higher than the above range, the metal tends to be thermally softened.

As the die for extruding the thermoplastic resin, a die generally used for resin extrusion coating, for example, coat hanger type die, fish tail type die,
Straight manifold dies are used. The thermoplastic resin is heated and kneaded in an extruder at a temperature higher than the melting temperature and extruded through the die.

It is also possible to extrude the thermoplastic resin as a laminate, and in this case, the number of extruders corresponding to the number of resins constituting the laminate is used, and the resin is extruded through the multiple multilayer die. Good to do.

At the time of extrusion, the width of the die lip is suitably in the range of 0.3 to 2 mm, while the extrusion speed is determined so that the ratio with the peripheral speed with the laminating roll will be in the range described later.

In the present invention, the peripheral speed of the warm laminating roll is maintained at 10 to 150 times, especially 20 to 130 times the extrusion rate of the thermoplastic resin from the die to thin the molten thin film of the thermoplastic resin. Preferably. Within this range, mechanical adjustment unevenness such as the die lip width is corrected to form a more uniform thin film, and stable lamination becomes possible. If this ratio exceeds the above range, the resin tends to break, which is not preferable. On the other hand, when the content is less than the above range, not only stable lamination is not performed, but also the object of the present invention of forming a sufficiently thin coating is not achieved.

For the use of the laminated material for can manufacturing, the ratio (tM / tR) of the thickness (tM) of the metal substrate to the coating resin film thickness (tR) per one side is 2 to 150. It is preferable in terms of processability into cans and properties of cans.

It is important that the contact width (nip width) at the nip position of the warm laminating roll is in the range of 1 to 50 mm in order to firmly adhere the metal base material and the thermoplastic resin. Is less than the above range, sufficient contact time cannot be obtained and the surface condition of the coating is poor and the adhesion is poor, and when it is more than the above range, it is difficult to increase the nip pressure, In the meantime, the laminating material tends to be cooled too much, and the adhesion tends to decrease. The pressure of the nip is preferably in the range of 1 to 100 kgf / cm ² .

In order to secure the above nip width, at least one of the warm laminating rolls is preferably an elastic roll.

The warm laminating roll preferably has a surface temperature of 50 ° C. to the melting point (Tm) -30 ° C. of the thermoplastic resin, and this temperature control is performed by using a liquid medium having a constant temperature in the roll. It can be carried out by a method known per se, such as passing through a hot roll or bringing a temperature-controlled backup roll into contact with a warm laminating roll.

The laminate material after completion of thermal bonding is rapidly cooled immediately after lamination to prevent thermal crystallization or thermal deterioration, or after being kept at a certain temperature, it is kept in a crystallization temperature range to prevent thermal crystallization. It is better to quench at that point before it arrives. This cooling is performed by blowing cold air, spraying cooling water,
It is performed by immersion in cooling water, contact with a cooling roller, or the like.

[0062]

EXAMPLES The present invention will be described in more detail with reference to the following examples.

[Embodiment 1] In the apparatus configuration shown in FIG. 1, a pair of T dies having a lip width of 0.8 mm and arranged so that the extruded molten resin film is guided onto a warm laminating roll (winding angle: 10 °). From, extruded isophthalic acid copolymerized polyethylene terephthalate (PET / IA) resin film having a melting point (Tm) of 220 ° C, and a pair of warm laminating rolls in which fluororubber is wrapped around an iron core and temperature is controlled to 130 ° C. (Nip width: 13m
m300), heated to 240 ° C. and having a thickness of 0.30 mm, A3004
A double-sided resin-coated laminated material was prepared by simultaneously laminating both sides on a coil material of -H19 aluminum alloy at a speed of 150 m / min, followed by a rapid cooling step with a water shower and a slight trim step on both sides of the coil.

A wax-based lubricant was applied to this double-sided resin-coated metal laminate material, which was punched out into a disk having a diameter of 150 mm and then molded into a squeezed container having a diameter of 92 mm according to a conventional method.

A JIS No. 5 tensile test piece was punched out from this double-sided resin-coated metal laminate material, and the tensile strength was measured according to the usual method to obtain a metal base having a correlation with the strength (particularly internal pressure resistance strength) when formed into a container. The degree of decrease in strength of the material was examined.

Further, a 10 cm square flat plate test piece was cut out from this double-sided resin-coated metal laminate material, subjected to heat treatment at 205 ° C. * 2 minutes, which is assumed to be the heat history in the printing process after can making, and then spread with rubber. Under a condition of 5 ° C. on a stand, a weight having a tip of 1 kg and a spherical shape of φ20 mm was dropped to give a dent (denting test), and damage to the resin film was observed.

The laminated material produced under the conditions satisfying the claims of the present invention has an average thickness of 1 on each side of the resin film.
At 3 μm (take-off speed ratio: approx. 62 times), the difference (thickness unevenness) between the maximum thickness part and the minimum thickness part in the coil width direction is 2 μm.
It was as small as m. Therefore, in the molding test as well, neither wrinkles nor breakage due to uneven thickness occurred, nor did defects such as breakage or peeling of the resin film occur. The denting test was also in good condition. In addition, the strength of the metal base material hardly deteriorated, and all were good double-sided resin-coated metal laminate materials.

[Comparative Example 1] Of the pair of T dies, one of the pair of T dies is such that the extruded molten resin film is in contact with the warm laminating rolls at a substantially right angle to the line connecting the centers of the pair of warm laminating rolls. The T-die is arranged so that the molten resin film is supplied to the nip part without being supplied, and the other extruded molten resin film is supplied to the nip part after it is wound around the warm laminating roll by 90 °. Same as Example 1 except that the temperature was set to 280 ° C., and a warming laminating roll on the side on which the resin film was wound 90 ° was wound through the resin film by 30 ° and then drawn into the nip portion. I tried to make a laminated material under the conditions.

However, the resin film on the side entering the right angle occasionally adheres to the warm laminating roll, and even in a relatively good laminated state, the base material is heated to such a degree that the strength cannot be put to practical use. Even though I did
It is thought that when the temperature was lowered while it was wound on the warm laminating roll of 30 ℃, it was below the substrate temperature required for bonding when it was laminated at the nip part, but the adhesive strength was very weak and sampling It peeled off at the time of. Further, the resin film on the opposite side had a thickness unevenness of 11 μm with respect to the average thickness of about 14 μm, and many bubbles were included in the adhesive interface between the metal substrate and the resin film. Therefore, it was not possible to produce a satisfactory laminate material.

[Comparative Example 2] Due to the structure of the T-die, the molten resin film extruded from the lip portion was brought into contact with the metal substrate immediately after extrusion, whereby the winding angle of the resin film on the warm laminating roll was determined. A laminate material was prepared under the same conditions as in Example 1 except that was set to 0 °. But,
The unevenness of the thickness of the resin film on each side was rather large, about 8 microns, and air bubbles were also entrained in the adhesive interface between the resin film and the metal substrate. In the draw forming test, it may be due to the occurrence of irregular banks of the molten resin film at the nip portion and the uneven fusion of the molten resin film with the metal substrate. There has occurred. Even in the denting test, there were portions where minute coating cracks occurred depending on the location. It should be noted that during lamination, the resin was often adhered to the warm laminating roll, and it was not a continuous and stable laminate material.

[Comparative Example 3] By arranging the T die, the winding angle of the extruded molten resin film around the warm laminating roll was 5
A laminate material was prepared under the same conditions as in Example 1 except that the temperature was 0 °. As a result, three thin portions were formed in the resin film of the laminate material in the longitudinal direction, which were relatively continuous in stripes (thickness unevenness: about 10 μm), and the portions wrinkled and collapsed during the drawing molding test.

[Comparative Example 4] The relationship between the extrusion speed and the plate-passing speed of the metal substrate (peripheral speed of the warm laminating roll) was adjusted so that the average coating resin film thickness on each surface after lamination was 5 μm. An attempt was made to prepare a laminate material under the same conditions as in Example 1 except that (take-off speed ratio: 160 times).
However, the molten resin film was cut and the laminate material could not be prepared.

[Comparative Example 5] The lip width of the T die was 0.2 m.
m, and the relationship between the extrusion speed and the stripping speed of the metal substrate (peripheral speed of the warm laminating roll) was adjusted so that the average coating resin film thickness on each side after lamination was 25 μm (take-off speed ratio). : 8 times) except that the laminated material was prepared under the same conditions as in Example 1. As a result, the accuracy of the uniform adjustment of the nip width by the metal base material width method was poor, and the thickness unevenness (about 22 μm) was considered to be the influence of the discharge amount fluctuation due to the pulsation of the extruder. Then, in the draw forming test, wrinkles were generated at that portion and the cylinder was crushed.

[Comparative Example 6] The laminating roll temperature was set to 25.
A laminate material was prepared under the same conditions as in Example 1 except that the temperature was set to be ° C, and the evaluation / test was performed. However, the resin film delaminated during the draw forming test.

[Comparative Example 7] A laminate material was prepared under the same conditions as in Example 1 except that the warm laminating roll temperature was 210 ° C. However, the deposition of the resin on the warm laminating roll occurred and the laminating material could not be prepared.

[Comparative Example 8] The same as Example 1 except that the warm laminating roll was a metal roll which was not elastically deformed (nip width: linear) at the time of nipping only by plating the surface of the iron core. An attempt was made to create a laminated material under the conditions. However, only a laminate material having a surface state in which air bubbles are entrapped between the coating resin film and the metal base material or the resin film itself has wrinkles is available.

[Comparative Example 9] Compared with Example 1, a fluorine rubber having a lower hardness is wound thicker and a nip width is 60 mm.
A laminate material was prepared under the same conditions as in Example 1 except that a pair of warm laminating rolls were used.
Used for evaluation and testing. However, probably because the nip pressure was low and the temperature was too low during the nip, the adhesive force of the resin film was weak and the resin film was delaminated during the drawing molding test.

[Example 2] As a metal substrate, a thickness of 0.2
A laminate material was prepared under the same conditions as in Example 1 except that a 3 mm A5052-H19 aluminum alloy was used, and was provided for evaluation and testing. Both the draw forming test and the denting test showed good results, and no defects such as breakage of the resin film and delamination occurred, and the double-sided resin-coated metal laminate material was good.

[Example 3] As a metal base material, a thickness of 0.2
A laminate material was prepared under the same conditions as in Example 1 except that 0 mm electrolytic chromic acid-treated steel plate was used, and the evaluation / test was performed. Both the draw forming test and the denting test showed good results, and no defects such as breakage of the resin film and delamination occurred, and the double-sided resin-coated metal laminate material was good.

[Example 4] As the thermoplastic resin film on one surface, the resin shown in Example 1 was used on the side in contact with the metal base material, and the same resin on the surface layer (air) side was added with TiO2, which is an inorganic pigment.
A laminate material was prepared under the same conditions as in Example 1 except that a two-layer melt-extruded resin film composed of a mixture of 0% was used, and was provided for evaluation and testing. Both the draw forming test and the denting test showed good results, and no defects such as breakage of the resin film and delamination occurred, and the double-sided resin-coated metal laminate material was good.

[0081]

According to the present invention, by combining the warm laminating roll system, the metal base straight traveling system and the warm roll conveying system of the resin, both surfaces of the metal material are simultaneously coated with the thermoplastic resin, and the resin is A double-sided resin-coated metal laminating material with a thin coating and high performance, that is, uniform thickness, high workability, high adhesion, and high film physical properties.
It can be manufactured at high speed with a small number of steps and a simple device.

Further, it is possible to prevent the heat softening of the metal, the thermal degradation of the resin and the thermal oxidation as much as possible, and it is a uniform thin film, but the adhesiveness to the metal is remarkably excellent. It has become possible to provide a resin-coated metal laminate material.

According to the present invention, the resin-metal laminate to be formed can withstand a large degree of working such as deep drawing, bending and stretching, and ironing, and a molded body after processing can be obtained. It also has excellent corrosion resistance and is useful for can manufacturing.

[Brief description of drawings]

FIG. 1 is a side view of a device used in the present invention.

FIG. 2 is a diagram for explaining a method of supplying a thermoplastic resin melt to a laminating roll.

FIG. 3 is a graph showing a relationship between a moving distance from a fixed position of a molten resin passage to a warm laminating roll and a resin temperature on a very surface on a roll contact side.

FIG. 4 is a graph plotting the relationship between the winding angle of the resin film and the film thickness unevenness.

[Explanation of symbols]

1 metal base material 2 passages 3 Metal base material heating area 4a, 4b Thermoplastic resin 5a, 5b die 6a, 6b Warm laminating roll 7 Laminated material 8 Quenching means 10 Nip position

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-86308 (JP, A) JP-A-2-241737 (JP, A) JP-A-63-5922 (JP, A) Actual Kaihei 4- 100844 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B29C 47/00-47/96 B29C 63/00-63/48 B32B 15/00-15/20

Claims (11)

(57) [Claims] 1. A method for simultaneously forming a resin coating on both sides of a metal base material, the heating area of the metal base material being relatively along the passage of the metal base material and the heated metal base material passage. A die for supplying the pair of thermoplastic resins in the form of a film,
A pair of warm laminating rolls for adhering the thermoplastic resin to both sides of the metal base material and a quenching means for quenching the laminating material to be formed are arranged, and between the pair of warm laminating rolls and at the center of the warm laminating rolls. Nip position between warm laminating rolls by passing through a heated metal base material in a direction almost perpendicular to the line connecting them and supporting and transporting the molten film of thermoplastic resin from each die with the corresponding warm laminating rolls. The method for producing a double-sided resin-coated metal laminate material, comprising: 2. The molten film of the thermoplastic resin from the die is introduced onto the warm laminating roll in a direction substantially tangential to the warm laminating roll and within a range in which the winding angle around the warm laminating roll is 2 to 45 degrees. Item 2. The manufacturing method according to Item 1. 3. The method according to claim 1 or 2, wherein the peripheral speed of the warm laminating roll is maintained at 10 to 150 times the extrusion speed of the thermoplastic resin from the die to thin the molten film of the thermoplastic resin. Method. 4. The temperature of the metal base material immediately before the nip has a melting point (Tm) of the thermoplastic resin of −80 ° C. to Tm + 50 ° C.
The manufacturing method according to any one of claims 1 to 3, wherein the heating is performed so as to reach the temperature. 5. The manufacturing method according to claim 1, wherein the contact width at the nip position of the warm laminating roll is in the range of 1 to 50 mm. 6. The manufacturing method according to claim 1, wherein at least one of the warm laminating rolls is an elastic roll. 7. The warm laminating roll according to claim 1, wherein each of the warm laminating rolls has a surface temperature lower than the temperature of the metal base material and from 50 ° C. to the melting point (Tm) -30 ° C. of the thermoplastic resin. The production method described in Crab. 8. The manufacturing method according to claim 1, wherein the ratio of the thickness of the metal base material to the thickness of the coating resin film per one surface is 2 to 150. 9. The production method according to claim 1, wherein the thermoplastic resin comprises a thermoplastic polyester, a copolyester, a blend thereof, or a laminate thereof. 10. The method according to claim 1, wherein at least one of the thermoplastic resins is a resin composition containing a pigment. 11. The manufacturing method according to claim 1, wherein the double-sided resin-coated metal laminate material is a laminate material for can manufacturing.