JPS61149341A - Manufacture of polyester resin film-covered metal plate - Google Patents

Abstract

PURPOSE:To improve the adhesion and corrosion resistance of a polyester resin film-covered metal plate that will be processed, by laminating at high speed continuously a metal plate surface with a biaxially orientated polyester (PET- BO) film having a special composition layer that faces the metal plate. CONSTITUTION:After a polymer composition in a state of a solution is applied to a PET-BO film, it is dried in a dryer oven. The drying temperature is 60-150 deg.C, and the thickness of the coating is preferably 0.1-5.0g/m<2> expressed as dry weight. The film is laminated on the surface of a metal plate that is heated to 220-260 deg.C with the applied polymer composition facing the metal plate surface. The polymer composition is one containing one or more of hydroxy groups, amide groups, ester groups, carboxylic groups, urethane groups and amino groups per molecule, and is solid at 20 deg.C and tack-free. An example of the composition is an epoxy resin, phenolic resin, polyester resin, etc. The laminated metal plate is excellent in corrosion resistance when it is processed, and can be used a container material such as a can end, and a drawn can.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for manufacturing a metal plate coated with a polyester resin film, and more specifically, a metal plate coated with a polyester resin film coated with a hydroxyl group, an amide group, an ester group, a carboxyl group, or a urethane group on one side. A biaxially oriented polyester film coated with a polymer composition having one or more of groups and amino groups in the molecule (J2 is the lower PE
This invention relates to a polyester resin-coated metal plate formed by laminating a T-BO film (referred to as T-BO film) on one or both sides of a metal plate heated to 220 to 260°C.

[Conventional technology]

Conventionally, in the can manufacturing industry, metal plates such as tinplate, electrolytic chromic acid treated copper plates, and aluminum plates have been coated once or multiple times.

Applying multiple coats in this manner not only complicates the baking process but also requires a long baking time. In addition, since a large amount of solvent components are discharged during coating film formation, the method has the disadvantage that the discharged solvent must be led to a special incinerator and incinerated in terms of pollution. In order to solve these drawbacks, attempts have been made to laminate a thermoplastic resin film to a metal plate. - Examples include a polyolefin film laminated to a metal plate (Japanese Patent Publication No. 53-141786), a copolymerized polyester film laminated to a metal plate (Japanese Patent Publication No. 57-1986)
-23584) or a polyester film laminated to a metal plate using an adhesive (JP-A-58-
39448).

[Problem that the invention sought to solve]

However, polyolefin film laminated steel sheets are not satisfactory in terms of corrosion resistance and heat resistance, and copolymer polyester laminated steel sheets have the disadvantage of being high in cost and lacking in practicality. In addition, polyester film-laminated steel sheets with an adhesive layer containing metal powder etc. at the interface between the polyester film and the metal sheet can ensure initial adhesion, but when subjected to high-temperature hot water treatment such as retort sterilization, the adhesion deteriorates. The adhesive has drawbacks such as a decrease in strength and lack of adhesive thin film coating properties because it contains metal powder and the like.

[Means for solving problems]

As a result of various studies to solve the above-mentioned problems, the present invention has developed a continuous PET-BO film that has a specific composition layer on one or both sides of a metal plate, and has a specific composition layer on the side in contact with the metal plate. It is characterized by its ability to laminate quickly and at high speed. The polyester resin-coated metal plate obtained by the method of the present invention not only has excellent processing adhesion and processing corrosion resistance, but is also an innovative product that does not lose its adhesion even when subjected to hot water treatment such as retort treatment. be. Hereinafter, the content of the present invention will be explained in detail. First, the PET-BO film is a polycondensate of polyethylene glycol and terephthalic acid, which is extruded from a known extruder and then formed into a film, then stretched in the longitudinal and transverse directions, and then subjected to a heat setting process. The film thickness is not particularly limited, but is preferably 5 to 50 μm. If the thickness is less than 5 μm, laminating workability will be significantly reduced and sufficient processing corrosion resistance will not be obtained. On the other hand, if it is 50μ or more, it is not economical when compared with epoxyphenol paints and polyethylene and polypropylene films that are widely used in the field of can manufacturing.

Next, the polymer composition to be applied to the PET-BO film contains one or more of the following: hydroxyl group, amide group, ester group, carboxyl group, urethane group, and amino group in the molecule, and Preferably, the composition is solid at 20°C and tack-free. Examples of these polymer compositions include epoxy resins, phenolic resins, nylon resins, modified vinyl resins, urethane resins, urethane resins, and polyester resins. Although the form of the polymer composition is not particularly limited, in order to apply a thin film, it is preferably in a solution state that can be roll coated. When using a polymer composition that has tackiness at 20°C, PET-
(Continuous on BO film): Even after coating and sufficiently evaporating the solvent with an open dryer, the composition remains sticky, so even if it is possible to wind the film,
It is completely impossible to unwind it, and it cannot be put to practical use.

Next, the step of applying the composition in a solution state to a PET-BO film and drying it with an open dryer is also important, and the drying temperature is preferably 60 to 150°C. If the drying temperature is lower than 60°C, the solvent removal property will be significantly reduced and the workability will be significantly reduced. On the other hand, the drying temperature is 15
If the temperature is 0° C. or higher, the reaction of the polymer composition will proceed significantly during the drying process, and as a result, the adhesion to the metal plate, which will be described later, will be significantly reduced.

The diluting solvent used when applying the polymer composition to a PET-BO film is not particularly limited, but a low boiling point solvent is preferred in consideration of drying properties when the dryer is open.

The process of applying the polymer composition to the PET-BO film is satisfactory as described above, but for the present purpose) coloring with dyes or the like may be added to the composition to improve its aesthetics to the extent possible. Agents may also be added.

Next, the coating thickness of the polymer composition is particularly important and is preferably 0.1 to 5.0 g/lri in dry weight, more preferably 0.5 to 2.0 g/lri. Osy/yy? is preferred. here,
If the coating weight is less than 0.1g/-, PET-
Difficulties arise in continuous application to BO film, making uniform application difficult. On the other hand, if the coating weight is 5.0Q/d or more, the adhesion strength tends to decrease if harsh processing such as deep drawing is performed after heating and integrating the metal plate and PET-BO film. It is in. Further, after coating on the PFiT-BO film, the solvent removal property when the dryer is opened is also decreased, resulting in a significant decrease in workability. The composition comprises PET-BO
Continuous to the film: dry weight 0.1 to 5-Oy/
Although it is possible to apply the composition within the range of rye, it is practically difficult to continuously apply the composition to a band-shaped metal plate due to severe restrictions.

The reason for this is that the shape of the metal plate is less flat than that of the PET-BO film, and the coatability of the thin film as in the present invention is significantly reduced. Additionally, compared to plastic film coaters, metal plate coaters require higher equipment costs.
It has various drawbacks.

Next, examples of the metal plate used in the present invention include sheet-shaped and coil-shaped steel plates, copper foils, iron foils, aluminum plates, aluminum foils, and metal plates subjected to surface treatment. In particular, electrolytic chromic acid treated steel sheets with a two-layer structure of metallic chromium on the bottom layer and chromium hydrated oxide on the top layer, ultra-thin silver-plated steel sheets, ultra-thin iron pan alloy coated steel sheets, ultra-thin chromium-plated steel sheets, nickel-plated steel sheets, zinc Metallic steel plate,
Chromium hydrated oxide-coated steel sheets, organic-treated steel sheets with polar groups such as carboxyl groups or chelate structures, or aluminum sheets subjected to phosphate treatment, chromate treatment, chromium-chromate treatment, or the above-mentioned organic treatment are , has excellent adhesion with the polymer composition.

Next, PET-BO coated with the polymer composition on one side
In the process of laminating the film to the metal plate, 2
The polymer composition is laminated on one or both sides of a metal plate heated to 20 to 260°C, more preferably 230 to 255°C, so that the coated side of the polymer composition is in contact with the metal plate.

After lamination, either rapid cooling or slow cooling may be performed. One of the features of the present invention is that adhesion appears instantaneously during lamination, and there is no need for heat activation treatment, such as reheating, which is generally practiced after lamination. Of course, it goes without saying that there is no problem in performing reheating treatment after lamination. If the lamination temperature is below 220° C., there will be almost no adhesion after lamination and it cannot be put to practical use. On the other hand, if the lamination temperature drops to 260℃ or higher, Pg
When the temperature exceeds the melting point of the T-BO film, the oriented crystals of the PET-BO film tend to collapse, resulting in poor processing adhesion and processing corrosion resistance.

Metal plate at 220-260℃, preferably L<): 1230
Methods for heating within the range of ~255°C include known hot air heat transfer methods, resistance heating methods, induction heating methods, heat roll heat transfer methods, etc., and are not particularly limited; In consideration of simplicity, the heat roll heat transfer method is preferable.

Next, the surface temperature of the laminating roll when laminating the PET-BO film to the metal plate is also an important factor in the present invention. That is, the surface temperature of the laminating roll is 80 to 20oC, more preferably 100 to 180oC.
It is necessary to control the temperature within the range of ℃. If the surface temperature of the laminating roll is 80° C. or lower, air bubbles are likely to form during lamination, and once air bubbles form, they cannot be improved even by reheating. This is made using PET-B in advance.
This is thought to be because the reactivity of the composition applied to the O film differs between the surface of the metal plate and the PET-BO film during the lamination process. That is, PET-
When laminating the composition applied to the BO film, the surface of the metal plate is heated to a high temperature of 220 to 260°C, and the composition easily reacts with the surface of the metal plate. On the other hand, regarding the temperature on the PET-BO side, the lower the surface temperature of the laminating roll, the lower the temperature at the interface between the PET-BO film and the composition, and the lower the reactivity between the polymer composition and the PET-BO film. I'll come. Therefore, at a roll surface temperature of 80°C or less, the composition applied to the PBT-BO film surface reacts well only with the metal plate, and the PUT-BO film
Due to its low reactivity with the film, it is transferred from the PET-BO film to the metal plate, resulting in the composition and PBT-BO film being transferred to the metal plate.
It is thought that air bubbles are likely to enter the interface with the BO film.

On the other hand, when the surface temperature of the laminate roll is 200° C. or higher, although no bubbles are generated, the biaxially oriented crystals of the PET-BO film tend to collapse and the processing corrosion resistance decreases. As for the material of the laminating roll, any of chrome-plated rolls, ceramic rolls, and rubber rolls can be used, but rubber rolls are preferable in order to perform high-speed and beautiful lamination. The rubber material of the rubber roll is not particularly limited, but silicone rolls with excellent thermal conductivity and heat resistance are preferred.

〔Example〕

Examples will be described in detail below. Example 1 A cold-rolled copper plate with a thickness of 0.21 ms was electrolytically degreased in a 70 g/l sodium hydroxide solution and pickled with a 100 Q/l sulfuric acid solution. After washing with water, chromic anhydride 60g/no,
In a solution of 3 i/l sodium fluoride, a current density of 20
A cathode electrolytic treatment was performed under the conditions of A/dtrt and an electrolyte temperature of 50° C., followed by immediately washing with hot water of 80° C. and drying. A PET-BO film treated under the following conditions was continuously laminated on both sides of the strip-shaped electrolytic chromic acid treated steel sheet having a width of 300 am treated in this way.

PBT-BO film 25μ door (product name Nilmirror manufactured by Toshiku Co., Ltd.) Dry coating amount of coating polymer composition 'L, Og/lri
Drying temperature of polymer composition: 120°C Heating method for steel plate Temperature of steel sheet immediately before heat roll heating lamination 245°C Laminating roll Silicon roll Surface temperature of laminating roll max 16
Cooling method after lamination at 4°C Slow cooling Example 2 A cold rolled steel sheet similar to that in Example 1 was subjected to the same pretreatment as in Example 1, and then treated with 259/l of tin sulfate and phenolsulfonic acid (60% aqueous solution). Using an electrolytic solution of
(1/d tin plating was applied, washed with water and dried. PET-BO film treated under the following conditions was continuously applied to both sides of the obtained strip-shaped copper-plated steel sheet with a width of 300 m under the following conditions. Laminated.

PET-BO film 16μ (trade name Nirmirror, manufactured by Toshiku Co., Ltd.) Dry coating amount of coated polymer composition 1-5 g/rft Drying temperature of polymer composition 100°C Method of heating steel plate Immediately before heat roll heating lamination Copper plate temperature 240°C laminating roll Silicon roll Laminating roll surface temperature max 190°C Cooling method after lamination Slow cooling Example 3 A cold-rolled copper plate similar to Example 1 was subjected to the same pretreatment as Example 1, and then Nickel chloride (hexahydrate) 40y/l, nickel sulfate (hexahydrate) 250 Q/1. Boric acid 4oy/
A current density of 10 A/dr.
Nickel plating was applied at a rate of 0.6 g/g under the conditions of 45° C. and a bath temperature of 45° C. After washing with water, add sodium dichromate 30 Q/
Chromate treatment was performed in a solution of It at a current density of 10 A/dWt and an electrolyte temperature of 45° C., followed by washing with water and drying. PET-BO films treated under the following conditions were continuously laminated on both sides of the resulting strip-shaped nickel-plated steel plate having a width of 300 square meters under the following conditions.

PET-BO film 50μ Tsuru (product name: Diafoil, manufactured by Diafoil (Ten)) Dry coating amount of coating polymer composition 4.5 g/d Drying temperature of polymer composition 80℃ Heating method of steel plate Heat roll Steel plate temperature just before heating lamination 225
°C laminating roll Silicone roll laminating roll surface temperature max 90 °C Cooling method after lamination Slow cooling example 4 An aluminum plate with a thickness of 0.30 wm was cathodic electrolytically degreased in a 3011/I soda solution, washed with water, and then phosphoroused. acid 6
ay/l, chromic acid 10g/j, sodium fluoride 5
After immersion treatment at a bath temperature of 25°C using a bath consisting of y/no,
Washed with water and dried. PET-B treated under the following conditions was applied to both sides of the obtained belt-shaped aluminum plate with a width of 300 mm.
The O film was continuously laminated under the following conditions.

PET-BO film 12μm (product name:
Dry coating amount of coated polymer composition (Lumirr, manufactured by Toshiku Co., Ltd.) 2.0 g/d Drying temperature of polymer composition
Heating method for 140°C aluminum plate Temperature of aluminum plate immediately before heat roll heating lamination 250°C 2 Mi*-) roll Silicon roll laminating roll surface temperature max 120°C Cooling method after lamination Slow cooling comparative example 1 Same as Example 1 Using steel plate, PET-BO film polymer composition, except for the surface temperature of the laminating roll,
Continuous lamination was performed under the same conditions as in Example 1 except for the following conditions.

Surface temperature of laminating roll max 65°C Comparative Example 2 Using the same steel plate and PET-BO film polymer composition as in Example 1, except for the surface temperature of the laminating roll,
Continuous lamination was performed under the same conditions as in Example 1 except for the following conditions.

Laminating roll surface temperature max 208°C Comparative Example 3 Using the same steel plate and PET-BO film polymer composition as in Example 2, the other conditions were the same as in Example 2 except for the dry coating amount of the polymer composition. Continuous lamination was performed under the same conditions.

Dry coating weight of epoxy resin/polyamide resin 0,05
l/d Comparative Example 4 Using the same aluminum plate and PET-BO film polymer composition as in Example 4, lamination was carried out continuously under the same conditions as in Example 4 except for the lamination temperature.

Temperature of the aluminum plate immediately before lamination: 280° C. The obtained metal plate coated with a polyester resin film was evaluated by the following test method, and the results are shown in Table 1.

(1) Measuring the amount of machining on metal plates The plating amount and film amount were measured using a fluorescent X-ray method.

(2) Adhesion between metal plate and polyester resin film A metal plate coated with a polyester resin film was punched out into a circular plate with a diameter of 80 m, and after drawing into a cylindrical cup with a drawing ratio of 2.0, it was placed in boiling water at 100°C. After 1 hour of hot water treatment, the degree of peeling of the polyester resin film on the body was divided into 5 grades, with 5 points indicating no peeling and 1 point indicating full peeling.

(3) Processability of polyester resin film coated metal plate
6. A cylindrical cup with an aperture ratio of 2.0 was prepared, the cup was filled with 204% of 3% NaCl, the end surface of a metal plate was used as a cathode, and a carbon electrode was inserted into the liquid as an anode; 6.
A 5V, 10Ω DC circuit was created and the current flowing through it was measured.

(4) Corrosion resistance of metal plate coated with polyester resin film.

A metal plate coated with a polyester resin film was punched into a disk with a diameter of 110 squares, first drawn into a cylindrical cup at a drawing ratio of 1.51, and then drawn again at a drawing ratio of 1.20; A shaped cup (total drawing ratio 1.81) was prepared. After repacking the contents of commercially available tuna dredging into this cup and heat sterilizing it at 120°C for 90 minutes,
It was immediately transferred to a vacuum cell and subjected to a storage test at 50°C for 6 months. After the storage test, the state of peeling between the film and the metal plate and the state of corrosion of the metal plate were visually observed.

〔Effect of the invention〕

PE'I'-BO on one or both sides thus obtained.
Metal sheets laminated with films have excellent processing corrosion resistance, so they can be used not only as materials for containers that require strict processing corrosion resistance, such as can lids and squeezed cans, but also for building materials, electrical appliances, etc. It can also be applied as a product component.

Claims (4)

[Claims] (1) A polymer composition having one or more of hydroxyl group, amide group, ester group, carboxyl group, urethane group, and amino group in the molecule on one side of the biaxially oriented polyethylene terephthalate film, and the polymer composition A polyester resin film obtained by laminating the film coated with the composition, which is solid at 20°C and tack-free, on a metal plate so that the surface coated with the composition is in contact with the metal plate. A method for producing a coated metal plate. (2) The coating amount of the composition is 0.1 to 5.0 in terms of dry weight.
The method for producing a metal plate coated with a polyester resin film according to claim 1, wherein the polyester resin film-coated metal plate is (3) The polyester resin according to claim 1, wherein the composition-applied side of a biaxially oriented polyethylene terephthalate film is laminated on one or both sides of a metal plate heated to 220 to 260°C. A method for producing a film-coated metal plate. (4) The method for producing a polyester resin film-coated metal plate according to claim 1, wherein the surface temperature of the laminating roll is 80 to 200°C.