JPS61149340A - Manufacture of polyester resin film-covered metal plate - Google Patents

Abstract

PURPOSE:To provide the titled metal plate that is heat-resistant and electrically insulative and will have adhesiveness and corrosion resistance when worked, by laminating a metal plate that is heated to the melting point of a biaxially orientated polyethylene terephthalate resin with the PET-BO film on one or both sides thereof using a laminating roll whose surface temperature is controlled to a specified temperature. CONSTITUTION:A PET-BO film is a polycondensate of a polyethylene glycol and terephthalic acid, and is preferably one that is obtained by extruding the polycondensate into a film, stretching the film longitudinally and laterally, and subjecting the film to a thermal setting step and preferably has a thickness of 5-300mum. The temperature of a metal plate just prior the laminating is from the melting point Tm of the PET-BO film to Tm+100 deg.C. The surface temperature of a laminating roll is controlled to 30-180 deg.C. Within 10sec after the laminating, the polyester resin film-covered metal plate is quenched to 100 deg.C or below. The thickness of the PET-BO resin is to be 15-95% of the whole of the PET resin layer.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for producing a metal plate coated with a polyester resin film, and more particularly, the present invention relates to a method for producing a metal plate coated with a polyester resin film, and more specifically, the melting point of a biaxially oriented polyethylene terephthalate resin film (hereinafter referred to as PET-BO film). The present invention relates to a method for producing a metal plate coated with a polyester resin film, in which a PI3T-BO film is laminated on the metal plate heated above, and has a PET-BO resin layer as an upper layer and a non-oriented PBT resin layer as a lower layer.

[Conventional technology]

Conventionally, metal plates obtained by laminating thermoplastic films onto metal plates have been widely used in a variety of fields such as electrical parts, furniture, storage cases, and interior and exterior building materials. Generally, the following method is well known as a method for continuously laminating a thermoplastic film on a metal plate. One is a roll coater that coats the adhesive onto the metal plate surface.

- After coating with a solvent, etc., volatile substances such as a solvent are evaporated, and then laminated and immediately cooled, or a post-heating treatment is performed and then cooled. The other one is
This is a method of laminating a thermoplastic resin film that can be thermally bonded by introducing a polar group or the like into a thermoplastic resin in advance.

Examples include a vinyl chloride resin-coated steel plate made by laminating a vinyl chloride resin film to a steel plate using an adhesive, a polyolefin film laminated to a metal plate (Japanese Patent Application Laid-open No. 141786-1986), and a copolymerized polyester film laminated to a metal plate. Laminated (Tokuko Sho 57-235
84) Alternatively, a polyester film laminated to a metal plate using an adhesive (Japanese Patent Laid-Open No. 58-3944)
8) etc.

[Problem that the invention seeks to solve]

However, PVC resin coated steel sheets are heat resistant.

The surface scratch resistance was not satisfactory, polyolefin resin-coated steel sheets had poor heat resistance and corrosion resistance, and copolymer polyester resin-coated steel sheets had the disadvantage of being high in cost and lacking in practicality. Furthermore, a metal plate in which a polyester film is laminated to a metal plate via an adhesive requires an adhesive coating process and an open facility for evaporating volatile substances such as solvents, resulting in a significant decrease in workability.

As described above, the thermoplastic resin-coated metal plates conventionally invented have advantages and disadvantages, and none of them are satisfactory.

[Failure to solve the problem]

Against this background, the present invention aims to develop PET that has excellent properties such as corrosion resistance, processability, electrical insulation, heat resistance, and chemical resistance.
- Focusing on BO film, the purpose is to provide a polyester resin film-coated metal plate in which PBT-BO film is laminated to a metal plate without using adhesives, etc., and it has the following characteristics and It is effective.

That is, the method of the present invention is characterized by laminating a PET-BO film continuously and at high speed on one or both sides of a metal plate that has been heated to the melting point of the PET-BO film or higher, and then rapidly cooling it. It is a thing,
In the metal plate coated with a polyester resin film obtained by the method of the present invention, the biaxially oriented crystals collapse only near the interface with the metal plate, resulting in a thin non-oriented and amorphous state, and the biaxially oriented crystal layer remains on the surface layer. It has a so-called two-layer structure, and has excellent properties such as processing adhesion, processing corrosion resistance, and chemical resistance.

In general, PET-BO films have oriented crystals and have excellent barrier properties against moisture and various ion permeability, and have therefore been used in various packaging material fields. In addition, it has extremely excellent mechanical properties and heat resistance, so it has been widely used in fields such as magnetic tape and electrical insulation, but because it has highly oriented crystals, it has no adhesion to adherends without an adhesive. It had the disadvantage of not having.

On the other hand, P13T in an unoriented, amorphous state obtained by heating a PET-BO film above its melting point and rapidly cooling it
Resin has such excellent adhesive strength that it is used as an adhesive between metal plates, as shown in Japanese Patent Publication No. 49-34180. However, non-oriented, amorphous PET resin has the drawbacks of significantly lowered barrier properties against moisture and various ion permeability, and also significantly lowered mechanical strength. As described above, PET resin has properties that vary greatly depending on whether or not it has oriented crystals.

The reason why the polyester resin film coated metal plate obtained by the method of the present invention has excellent processing adhesion and processing corrosion resistance is as follows.
As already mentioned, the non-oriented, amorphous PET resin layer with excellent adhesive strength is thinly and uniformly formed on the surface in contact with the metal plate, and the upper layer of the non-oriented, amorphous PET resin layer is This is thought to be due to the presence of a PET-BO resin layer that has barrier properties against water and various ions and has excellent mechanical properties, and the two are well balanced.

The polyester resin film coated metal plate according to the present invention is
Because it has many excellent properties such as processing adhesion, processing corrosion resistance, heat resistance, and electrical insulation, PET resin is used not only as a material for cans such as can lids, squeezed cans, and double-drawn cans, but also as an electrical material for PET resin. It can also be used as a component for electrical products due to its insulation and heat resistance properties.

Hereinafter, the content of the present invention will be explained in detail.

First, the PET-BO film is made of a polycondensate of polyethylene glycol and terephthalic acid, which is formed into a film after a known extrusion process, and then stretched in the longitudinal and transverse directions, and then subjected to a heat setting process. It is something that has passed through
The film thickness is not particularly limited, but
5 to 300 μm is preferable. If the film thickness is less than 5 μm, the lamination workability will be significantly reduced, and it will be very difficult to achieve a good balance between the non-oriented, amorphous PET resin layer and the two-wheel oriented PET resin layer after lamination. becomes difficult. On the other hand, when the thickness is 300 μm or more, although properties such as processing corrosion resistance and electrical insulation properties are ensured, it is inferior in economic efficiency. These films can be heated or
Light stabilizer, antioxidant.

Additives such as pigments and antistatic agents may be added, or activation treatment such as corona discharge treatment may be performed to improve adhesion.

(2) Metal plates used in the present invention include V-shaped and coiled steel plates, steel foils, iron foils, aluminum plates, aluminum foils, and surface-treated metal plates. In particular, electrolytic chromic acid treated steel sheets with a two-story structure of metallic chromium on the bottom layer and chromium hydrated oxide on the top layer, ultra-thin tin-plated steel sheets, ultra-thin iron pot alloy coated steel sheets, ultra-thin chromium-plated steel sheets, nickel-plated steel sheets, copper. plated steel plate,
Galvanized steel sheets, chromium hydrated oxide-coated steel sheets, organic-treated steel sheets with positive groups such as carboxyl groups or chelate structures, and aluminum sheets treated with phosphate, chromate, or the above-mentioned organic materials are pg'r.
- Since it has particularly excellent adhesive strength with the BO film, it is suitable as the metal plate used in the present invention. Furthermore, the following two-layer and three-layer coated steel sheets, two-alloy plated steel sheets, and composite plated steel sheets are also suitable. Examples include steel sheets coated with these metals with chromate treatment, phosphate treatment, chromium-chromate treatment or organic treatment, double or triple plating of these metals, steel sheets coated with alloys such as nickel tin, small amounts of Examples include composite galvanized steel sheets containing at least one of nickel, cobalt, iron, chromium, and molybdenum in the form of metals or compounds.

Next, PET, which is one of the important factors in the present invention,
- The temperature of the metal plate just before laminating the BO film is the melting point (Tm) of the PET-BO film ~ (Tm+
100)'C. Furthermore, what is the melting point (Tm) referred to here?

It is determined from the endothermic peak of a differential scanning calorimeter (DSC) at a heating rate of 10°C/-, and the point indicating the maximum depth of the endothermic peak is called Tm. If the temperature of the metal plate is below Tm, the PEIT-BO film will not become sufficiently non-oriented or amorphous on the surface of the laminated PET-BO film that comes into contact with the metal plate, and sufficient adhesive strength will not be obtained.

On the other hand, when a metal plate is heated above (Tm+100)'C, most of the laminated PET-BO film becomes non-oriented and amorphous, and properties such as processing corrosion resistance and electrical insulation properties are also deteriorated. Also, (Tm +100)℃
At higher temperatures, the shape (flatness) of the metal plate also tends to collapse.

Next, the surface temperature of the laminating roll when laminating the PET-BO film onto the metal plate is also an important factor in the present invention. That is, the two-layer structure of the PET-BO film of the present invention is obtained by applying PUT to the laminating roll nip.
-It is uniquely determined during a very short period of time when the BO film is in contact with it. That is, when a PET-BO film is laminated to a metal plate heated to a high temperature, the PET-B
A temperature gradient occurs in the O film, with the metal plate side being high temperature and the laminating roll side being low temperature. While passing through the laminating roll, a temperature gradient continues to occur in the PET film,
The temperature of the metal plate decreases due to the heat of fusion of the oriented crystals of the PET film and the heat absorbed from the laminating roll.

The moment the laminated metal plate comes out of the nip of the laminating roll, there is no temperature gradient in the PUT film, and the temperature matches the temperature of the metal plate. Therefore, it is necessary to lower the temperature of the metal plate to below the biaxially oriented fracture initiation temperature (TO) of the PUT-BO film while passing through the laminating roll. In order to create such conditions, the surface temperature of the laminating roll is a particularly important factor. That is,
It is necessary to control the surface temperature of the laminating roll to 30-180°C, preferably 50-150°C.

When the surface temperature of the laminating roll exceeds 1806C, when a PEIT-BO film is laminated onto a metal plate, the biaxially oriented crystals in all layers of the film will collapse, and the processing corrosion resistance will deteriorate, although it depends on the thickness of the PET-BO film. , electrical insulation properties etc. deteriorate. On the other hand, if the surface temperature of the laminating roll is to be lower than 30° C., it is necessary to attach a special cooling device such as external cooling to the laminating roll itself, which is not preferable because the equipment becomes large-scale.

Controlling the surface temperature of the laminating roll becomes more important as the laminating speed increases. The material of the laminating roll is chrome plated roll.

Both ceramic rolls and rubber rolls can be used, but rubber rolls are preferred for high-speed and beautiful lamination. The rubber material of the rubber roll is not particularly limited, but a silicone roll with excellent thermal conductivity and heat resistance is preferred.

Next, the cooling conditions after laminating the PEIT-BO film on the metal plate are also an important factor in the present invention.

In other words, it is important to rapidly cool the polyester resin film-coated metal plate to below 100°C within 10 seconds after lamination, and if it is kept at a temperature of 100°C or higher for a long period of time, the metal plate formed at the interface of the metal plate during lamination may The oriented, amorphous PET resin layer becomes coarse spherulite, and the processing adhesion and processing corrosion resistance are greatly reduced. The method of rapid cooling is not particularly limited, but preferred are an underwater immersion method, a water spray method, and the like.

Next, methods for heating the metal plate include the well-known hot air heat transfer method, resistance heating method, and induction heating method.

Examples include a heat roll heat transfer method, and although it is not particularly limited, the heat roll heat transfer method is preferable in consideration of equipment cost, simplification of equipment, and short-time temperature rising characteristics.

1: The amount of non-oriented, amorphous PET resin produced after laminating the PFliT-BO film onto a metal plate is also an important factor, and the thickness of the PPfT-BO resin is approximately 1% of the total PET resin layer.
It is important that the number is between 5 and 9596.

The thickness of the PFfT-BO resin layer is 9s of the total PET resin layer.
If it exceeds %J2L, the processing adhesion will be poor and peeling will occur easily, especially when deep drawing is performed. On the other hand, if it is less than 15% 1, the workability, corrosion resistance, electrical insulation properties, etc. will be significantly reduced. In this way, the remaining amount of biaxially oriented crystals is an important factor, but as a means of determining the remaining amount of biaxially oriented crystals,
Birefringence method, density method.

For example, it can be determined by X-ray diffraction method.

(1') The X-ray diffraction intensity of the PBT-BO film before lamination and the PFIT film after lamination is measured in the range of 20=20 to 30°.

(2) Connect the X-ray diffraction intensity curves at 20° and 2θ=30° with a straight line to form a baseline.

(3) Measure the height of a sharp peak near 2θ-26° from the baseline.

(4) The peak height of the film before lamination is Ia
When the peak height of the film after lamination is Ib, Ib/Ia x 100 is the remaining amount of biaxially oriented crystals.

〔Example〕

Example C will be described in detail below.

Example 1 A cold-rolled steel plate with a thickness of 0.2 Lm was electrolytically degreased in a 70 v'l sodium hydroxide solution, pickled with an IoOg7z sulfuric acid solution, washed with water, and then treated with 30 g/l of chromic anhydride and fluoride. In a solution of 1.5 g/l sodium chloride, the current density was 2
0A/drn2. Cathode electrolytic treatment was performed at an electrolyte temperature of 30°C, followed by washing with hot water at 80°C and drying.

A 16 μm thick P13T-BO film (trade name: Lumirror Higashishi) was continuously laminated on both sides of the electrolytically chromic acid treated steel plate having a width of 300 mm under the following conditions.

Heating method for steel strips・・・・・・・・・・・・・・・・
・Temperature of steel plate just before heat roll heating lamination・・
・・・・・・・・・290℃ lamination $-) Roll...
・・・・・・・・・・・・・・・・・・Surface temperature of silicone roll laminating roll・・・・・・・・・
・・・・・・max 90℃ laminated steel plate is 1
Time until it cools down to below 00℃・・・・・・・・・・・・
The amount of biaxially oriented crystals in the polyester resin film-coated steel plate obtained for 2 seconds was calculated using the X-ray diffraction method under the following conditions.

Diffraction conditions Target: Cu Tube voltage 4OKV Tube current 2QmA Method for calculating the amount of biaxial orientation (1) The film before lamination and the coated metal plate after lamination were measured in the range of 2θ-20 to 30', respectively.

(2) The X-ray diffraction intensity curves at 2θ-20° and 20=30° were connected with a straight line to form a baseline.

(3) The peak height of a sharp peak appearing around 2θ-26° was measured from the baseline.

(4) The peak height of the film before lamination is Ia
, where Ib is the peak height of the film after lamination, Ib/Ia x 100 is the remaining amount of biaxially oriented crystals.

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 25 g/l of tin sulfate, 15 g/l of phenolsulfonic acid (60% aqueous solution), and ethoxylation α. - using an electrolyte of 2 v'l of caphtolsulfonic acid and a current density of 20 A/dm2. @ Apply tin plating with 0.3 g/m2 of tin at a vinegar solution temperature of 40°C and wash with water.

Dry. This 300m wide tin-plated steel strip has a thickness of 3
An 8 μm PET-BO film (trade name: Lumirror, manufactured by Toshi ■) was continuously laminated on both sides under the following conditions.

Heating method for steel strips・・・・・・・・・・・・・・・・
・Temperature of steel plate just before heat roll heating lamination・・
・・・・・・・・・280℃ lamination $-) Roll/beat/
...Song/Song...Surface temperature of silicone roll laminating roll...16
The time it takes for a 0°C laminated steel plate to cool down to 100°C or less...
...-3 seconds The amount of biaxially oriented crystals in the obtained polyester resin film-coated steel plate was determined by X-ray diffraction in the same manner as in Example 1.

Example 3 A cold-rolled steel sheet similar to that in Example 1 was subjected to the same pretreatment as in Example 1, and then 40 g/l of nickel chloride (hexahydrate), 250 g of nickel sulfate (hexahydrate), and boric acid were added. 40g/l
using a Watts bath consisting of a current density of 10 A/dm”
, 0.6 g/m2 (D nickel plating was applied at a bath temperature of 45°C. After washing with water, 30 g/m2 of sodium dichromate was applied.
g/l solution with a current density of 10Aβm2. Chromate treatment was performed at an electrolyte temperature of 45° C., followed by washing with water and drying. Among these, a 188 μm thick PET-BO film (trade name: Lumirror, manufactured by Toshi ■) was continuously laminated on both sides of the 300 m+s nickel-plated steel strip under the following conditions.

Heating method for steel strips・・・・・・・・・・・・・・・・
・Temperature of steel plate just before heat roll heating lamination・・
・・・・・・・・・・・・350℃ Lamination 4-) Roll ・・・・・・・・・・・・・・・・・・ Silicon roll lamination roll surface temperature...・・・・・・
・・・・・・10 steel plates laminated at 120℃
Time until it cools down to below 0℃・・・・・・・・・・・・・・・
The biaxially oriented crystal wind of the polyester resin film-coated steel plate obtained for 8 seconds was determined by X-ray diffraction in the same manner as in Example 1.

Example 4 An aluminum plate with a thickness of 0.30 m was cathodic electrolytically degreased in an ao g/l sodium carbonate solution, and after washing with water, it was degreased with phosphoric acid.
60 g/l, chromic acid 10 g/l! , using a bath consisting of sodium fluoride s g/l, at a bath temperature of 25°C.
After immersion treatment, it was washed with water and dried. A 75 μm thick PET-BO film (trade name: Diafoil, manufactured by Diafoil ■) was continuously laminated on both sides of this strip-shaped aluminum plate with a width of 300 mm under the following conditions.

Heating method for strip aluminum plate・・・・・・・・・・・・・・・Temperature of aluminum plate just before heat roll heating lamination・・・・・・・・・
······················song··
・・・・・・300℃ lamination roll・・・・・・・・・
・・・・・・・・・Surface temperature of silicon roll laminating roll...4...curve...40℃ Time until the laminated aluminum plate is cooled to below 100℃...・・・・・・
The amount of biaxially oriented crystals in the polyester resin film-coated aluminum plate obtained for 1 second was determined by X-ray diffraction in the same manner as in Example 1.

Example 5 Aluminum plate with a thickness of 0.30 ++ m at 30 g/l
After cathodic electrolytic degreasing in a sodium carbonate solution and washing with water, 30g/
Chromate treatment was performed using 1 ml of sodium dichromate solution, followed by washing with water and drying. A 25 μm thick PET-BO film (trade name: Diafoil, manufactured by Diafoil ■) was continuously laminated on both sides of this 300 mm wide strip aluminum plate under the following conditions.

Heating method for a strip-shaped aluminum plate...Four curves...Temperature of the aluminum plate just before heat roll heating and lamination...
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・270℃ lamination roll・・・・・・
・・・・・・・・・Surface temperature of silicone roll laminating roll・・・・・・・・・・・・120
°C Time until the laminated aluminum plate is cooled to below 100 °C...
The amount of biaxially oriented crystals in the polyester resin film-coated aluminum plate obtained for 5 seconds was determined by X-ray diffraction in the same manner as in Example 1.

Comparative Example 1 Using the same PET-BO film and steel plate as in Example 1, lamination was carried out under the same conditions except for the surface temperature of the laminating roll.

Surface temperature of laminating roll: max. 210° C. The amount of two-wheel oriented crystals in the obtained polyester resin film-coated steel plate was determined by X-ray diffraction using the same method as in Example 1.

Comparative Example 2 Using the same PET-BO film and steel plate as in Example 1, lamination was carried out under the same conditions except for the cooling conditions after Urine F.

Time until the laminated steel plate is cooled to below ioo℃・・・・・・・・・・・・
...25 seconds The amount of biaxially oriented crystals in the polyester resin film-coated steel sheet obtained was determined by X-ray diffraction in the same manner as in Example 1.

Comparative Example 3 Using the same aluminum plate and PET-BO film as in Example 4, lamination was performed under the same conditions except for the lamination temperature.

Temperature of aluminum plate just before lamination...
The amount of biaxially oriented crystals in the polyester resin film-coated aluminum plate obtained at 255°C was determined by X-ray diffraction using the same method as in Example 1. Required by law.

Comparative Example 4 Using the same aluminum plate and PET-BO film as in Example 5, lamination was performed under the same conditions except for the lamination temperature.

Temperature of aluminum plate just before lamination...
The amount of biaxially oriented crystals in the polyester resin film-coated aluminum plate obtained at 405°C was determined by X-ray diffraction using the same method as in Example 1. Required by law.

The polyester resin film-coated metal plate was evaluated by the following test method, and the results are shown in Table 1, C-2.

(1) Measurement of plating amount on metal plate 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 disc with a diameter of 80mm, and the drawing ratio was 2. ．． After applying a drawing process to the cylindrical cup at 0.0°C, it was subjected to hot water treatment for 1 hour in boiling water at 100°C. 5 as 1 point
Divided into stages.

(3) Processing Corrosion Resistance 50 minutes of citric acid adjusted to pH 2.2 was poured into the cylindrical cup described in item (2) above, left at 55°C for 30 days, and eluted iron or eluted aluminum was measured.

In addition, 3% NaCl was placed in the same cup, and after being left at 55° C. for 30 days, the corrosion status was investigated with the naked eye.

〔Effect of the invention〕

The thus obtained metal plate laminated with PBT-BO film on one or both sides has excellent processing corrosion resistance and processing adhesion C; and is therefore suitable as a material for containers.

It can be applied to a wide range of applications such as building materials and electrical equipment components.

Claims (1)

[Claims] Melting point (Tm) of biaxially oriented polyethylene terephthalate resin
) ~ (Tm + 100℃) When laminating a PET-BO film on one or both sides of a metal plate heated to (Tm + 100℃), the surface temperature of the lamination roll is controlled to 30 to 180℃ within 10 seconds after lamination. Cool to below 100°C and add PET-
It has a BO resin layer, a non-oriented PET resin layer as a lower layer, and the thickness of the PET-BO resin layer is 15 to 15 times the total PET resin layer.
95% of the polyester resin film.