JPS62279937A - Resin coated steel plate for vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a resin-coated m-slope for containers. More specifically, it is a resin-coated steel sheet for containers that has excellent aesthetics and processing corrosion resistance.

[Conventional technology]

Conventionally, in the can manufacturing industry, surface-treated steel sheets such as tinplate and electrolytic chromic acid treated steel sheets have been coated once or multiple times. 2. Because tin has a glittering property, it has been widely used in applications where appearance is important. Applying multiple coats in this way not only requires a complicated baking process, but also (However, it required a long baking time.Also, it had the disadvantage that a large amount of solvent components were discharged during coating film formation and had to be led to a special incinerator and incinerated. Since the paints used in the coatings were mainly thermosetting resins with epoxy resin as the main component, harsh processing could cause cracks in the coating film, and as a result, depending on the contents, the surface treatment In some cases, it corroded the steel plate.In order to solve these drawbacks, attempts have been made to laminate a thermoplastic resin film to a metal plate (for example, a polyolefin film laminated to a metal plate). (Unexamined Japanese Patent Publication No. 53-14178
6) A copolymerized polyester resin film laminated on a metal plate (Japanese Patent Publication No. 57-23584), or a polyester film laminated on a metal plate (binary layer) using an adhesive (Japanese Patent Publication No. 58-39448). be.

[Problem that the invention seeks 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, the interface between polyester film and metal plate (2. Polyester film-laminated steel plate with an adhesive layer containing metal powder, etc.) can secure initial adhesion, but will adhere if subjected to high-temperature hot water treatment such as retort sterilization. It also had drawbacks such as a decrease in strength, and a lack of adhesive thin film coating properties due to the presence of metal powder.In addition, the plastic film-laminated steel plate (; the steel plate used was Although it is possible to use tinplate, which has excellent aesthetics, it is not practical because it is expensive.

[Means for solving problems]

As a result of various studies to solve the above-mentioned problems, the present invention has developed a resin-coated steel sheet in which a biaxially oriented polyethylene terephthalate resin film having a specific M vapor deposition layer is laminated on one or both sides of the steel sheet. This is a revolutionary resin-coated steel sheet for containers that not only has excellent processing adhesion and processing corrosion resistance, but also has excellent aesthetics.

The contents of the present invention will be explained in detail below.

First, the biaxially oriented polyethylene terephthalate resin film is a polycondensate of polyethylene glycol and terephthalic acid, which is extruded from a known extruder and then formed into a film. Although the film thickness is not particularly limited, it is preferably from 5 to 501 tm.If the thickness is less than 5 μm, the lamination workability on steel plates will be significantly reduced, and sufficient processing corrosion resistance will not be obtained. On the other hand, when it is 50 μm or more, it is not economical when compared to epoxy resin paints that are widely used in the can manufacturing field.

As a pre-treatment process for vapor depositing the film (-1), in order to improve the adhesion between the vapor deposited M and the film, an epoxy resin and its curing agent such as phenol, urea, amide, or ester are added to the film. o, acrylic-based, urethane-based composition, by dry coating weight,
o It is preferable to apply 5 to 5.0 g/m2.

The epoxy resin used here is preferably an epoxy resin with an epoxy equivalent of 400 to 4.000. When an epoxy resin with a CX0 epoxy equivalent of 400 or less is used, it is continuously applied to the film in a solution state, and then heated in a dryer oven. Even after the solvent is evaporated, the epoxy resin remains sticky, so although it is possible to wind the film, it is completely impossible to unwind it, making it impractical. On the other hand, when an epoxy resin having an epoxy equivalent of 4.000 or more is used, there is a tendency C: that the adhesion to the film decreases after the curing reaction with the curing agent, which is not preferable.

The blending ratio of the epoxy resin and the curing agent varies depending on the type of curing agent and cannot be determined uniquely, but it is generally 5 to 100 parts by weight per 100 parts by weight of the epoxy resin solid content.

Next, the reason why it is preferable that the coating weight of the composition consisting of an epoxy resin and its curing agent is within the range of O,OS~s,o g/m2 is that if the weight is 0.05 g/m2 or less, the film There is a tendency for the adhesion with the M vapor deposited layer to partially decrease due to difficulty in uniformly coating the film.On the other hand, if the coating weight is 5.0 g/m2 or more,
I! Although adhesion to the vapor-deposited layer is ensured, after application to the film, the ability to remove the solvent in a dryer oven decreases, resulting in a significant decrease in workability.

Next, the step of coating the film with a composition comprising an epoxy resin and its curing agent in a solution state and then drying it in a dryer oven is also important, and the drying temperature is preferably within 60 to 150°C. If the drying temperature is below 60°C, the solvent releasability will be significantly reduced and the workability will be greatly reduced.On the other hand, if the drying temperature is above 150°C,
The reaction between the epoxy resin and its curing agent progresses significantly, and as a result, the adhesion between the film and the M vapor-deposited layer decreases.

Next, M is applied by vacuum evaporation method or the like (from 50 to 30%
It is preferable to deposit within the range of 00A. Here, the method for depositing M may be any known vacuum deposition method and is not particularly limited. If the deposition thickness is less than 50X, the aesthetics will not improve; 3. If the OOOX is used for construction, the aesthetics can be ensured, but the deposition rate must be reduced, resulting in a significant drop in productivity.

Next, the epoxy resin and its curing agent interposed between the steel plate and the biaxially oriented polyethylene terephthalate resin film have an epoxy equivalent of 400 to 4. OOO epoxy resin and a curing agent made of one or more of phenol type, urea type, amide type, ester type, acrylic type, and phrethane type are preferable, and the coating weight is 0.000% on dry weight.
1 to 5.0 g/m2 is preferred.

Here, the method of applying the composition consisting of an epoxy resin and its curing agent at a dry weight of 0.1 to s, og/fn2 is as follows: There is a method of applying the composition to one side and a method of continuously applying the composition to the steel plate. This is practically difficult due to severe restrictions.

The reason for this is that the shape of the steel sheet lacks flatness compared to a biaxially oriented polyethylene terephthalate resin film, and the thin film coating properties of the present invention are significantly reduced.

Furthermore, compared to coaters for plastic films, coaters for steel plates have various drawbacks such as higher equipment costs.

For this reason, it is preferable that the composition consisting of an epoxy resin and its curing agent interposed between the steel plate and the biaxially oriented polyethylene terephthalate resin film be applied to the non-vapor-deposited surface of the M-deposited polyethylene terephthalate resin film.

Here, the epoxy equivalent of the epoxy resin is 400 to 4.
The reason why OOO is preferable is the same reason as mentioned above.
If it is less than 00, the epoxy resin is sticky and cannot be unrolled; and 4. OO
If it is 0 or more, the adhesion to the biaxially oriented polyethylene terephthalate resin film and steel plate after reaction with the curing agent tends to decrease, which is not preferable.

Although the blending ratio of the epoxy resin and the curing agent cannot be uniquely determined depending on the type of curing agent, it is generally sufficient to add 5 to 100 parts by weight per 100 parts by weight of the epoxy resin solid content.

Next, the dry coating weight of the composition is 0.1 to 5.0 g/m.
The reason why the range of 2 is preferable is 0.1 g/m2
If the amount is below, it will be difficult to coat the biaxially oriented polyethylene terephthalate resin film continuously and uniformly.

On the other hand, if it is 5.0 g/m2 or more, the adhesion strength will decrease if severe processing such as deep drawing is performed after heating and integrating the steel plate and the biaxially oriented polyethylene terephthalate resin film described below. There is a tendency to Moreover, after coating on the biaxially oriented polyethylene terephthalate resin film,
When the dryer is open, the solvent removal properties are also reduced and workability is significantly reduced.

Next, the step of drying with the dryer open is also important, as mentioned above (preferably within 160 to 150°C. If the drying temperature is below 60'C, the solvent separation property will be significantly reduced. , 15Q'C or higher, the reaction between the epoxy tree fertilizer and its curing agent progresses significantly during the drying process, and as a result, the adhesion to the steel plate described below is significantly reduced.

Next, examples of the steel plate used in the present invention include sheet-shaped and coil-shaped steel plates, steel foils, iron foils, and surface-treated steel plates.

Special C2, electrolytic chromic acid treated steel sheet with a two-layer structure of chromium hydrated oxide on the upper layer and metallic chromium on the lower layer, nickel-plated steel sheet, galvanized steel sheet, chromium hydrated oxide-coated steel sheet, polar groups such as carboxyl groups Alternatively, organic matter-treated steel sheets having a chelate structure, or phosphate-treated or chromate-treated steel sheets may be used.

Next, an example of a method for laminating the biaxially oriented polyethylene terephthalate resin film on the above-mentioned steel plate is as follows:
One side or both sides (-,
The surface coated with the epoxy resin composition is laminated so that it is in contact with the surface of the steel plate. After lamination, either a rapid cooling or slow cooling process 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 after lamination, which is commonly practiced. Needless to say, there is no problem with reheating the laminating temperature at 22.
If the temperature is below 0°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 is 260° C. or higher, the temperature will be higher than the melting point of the biaxially oriented polyethylene terephthanate resin film, the oriented crystals of the resin film will collapse, and the processing adhesion and processing corrosion resistance will decrease.

The steel plate is heated to 220 to 260°C, preferably 230 to 255°C.
Examples of methods for heating within the range of ℃ include the publicly known hot air heat transfer method, resistance heating method, induction heating method, and heater roll heat transfer. In consideration of the cost, the heater roll heat transfer method is preferable.

The thus obtained M-deposited biaxially oriented polyethylene terephthalate resin film laminated steel sheet has excellent appearance, processing corrosion resistance, and processing adhesion, and can be widely used as a resin-coated steel sheet for containers. However, it requires retort sterilization treatment. Contents (for one pair, as a top coat on the M vapor deposition layer,
It is preferable to overcoat with conventionally used epoxy/phenol paints, epoxy/area paints, vinyl paints, organosol paints, and the like.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 A cold-rolled steel plate with a thickness of 0.21 ounces was electrolytically degreased in 70 g of a trichum hydroxide solution, pickled with a 100 g/l sulfuric acid solution, washed with water, and then treated with 60 g/l of chromic anhydride. In a solution of 3 g/l sodium fluoride, the current density is 20 A/d.
Cathode electrolytic treatment was performed under the conditions of rrI2 and electrolyte temperature of 50° C., and immediately washed with hot water of 80° C. and dried.

The amount of metallic chromium in the obtained electrolytic chromic acid treated steel sheet was 120
In mg/m2, the amount of hydrated chromium oxide is 10 as chromium.
■/m2.

A biaxially oriented polyethylene terephthalate film treated under the conditions shown below was continuously laminated on one side of the electrolytic chromic acid treated steel sheet thus treated under the conditions shown below.

M vapor deposition layer thickness: 400 AM Dry weight of epoxy resin composition in the lower layer of vapor deposition layer: 0.08 g/rn
2 Biaxially oriented polyethylene terephthalate film (product name Lumirror East) 12μ
Dry ffi of epoxy resin composition for lower layer of m biaxially oriented polyethylene terephthalate film 0.5 g/
Heating method for rn2 steel sheet Heater roll method Steel sheet temperature immediately before lamination 245°C Cooling method after lamination One side (non-laminated side) of the slowly cooled M vapor-deposited resin coated steel sheet
epoxy/phenolic paint with a dry weight of 60 mg
/dm2C (two wheel cloth), heat-cured at 200'(200') for 10 minutes, and then slowly cooled.

The M vapor-deposited resin-coated steel sheet is A! ! A 202 type can lid and a drawn can with a drawing ratio of 2.14 were obtained with the vapor deposition surface facing the outer surface. The molded can lid and squeezed can were double-sealed using a known can manufacturing method, but there was no peeling of M from the biaxially oriented polyethylene terephthalate film, and the film had a shiny appearance. In addition, we have created a container that is double-sealed and integrated into three
After aging for 10 days at 7° C. and relative humidity of 9°C, no external rust was observed, and no peeling of M was observed at all.

Comparative Example 1 A biaxially oriented steel sheet treated with electrolytic chromic acid as in Example 1 was treated under the same conditions as in Example 1, except that only the epoxy resin composition below the M vapor deposition layer was removed. A polyethylene terephthalate film was laminated in the same manner as in Example 1, and another single-sided C epoxy/phenol paint was applied so that the dry weight was 6019/dIT+2, and the film was heated and cured at 200°C for 10 minutes. After that, it was slowly cooled.

The M vapor-deposited resin-coated steel plate was made such that the M vapor-deposited surface was the outer surface to obtain a 202-type can lid and a drawn can with a drawing ratio of 2.14. When the molded can lid and squeeze can were double-sealed using a known can-making method, the vapor-deposited M layer was partially peeled off from the biaxially oriented polyethylene terephthalate film near the double-sealed area. In addition, the double-sealed and integrated container is heated to 37°C.
After aging for 10 days under a relative humidity of 9096, no rust was observed on the outer surface, but some of the vapor deposited M near the double seam of the drawing can was missing.

Example 2 A cold-rolled steel plate with a thickness of 0.21 mm was electrolytically degreased in a 70 g/l sodium hydroxide solution, pickled with a 100 g/l sulfuric acid solution, washed with water, and then treated with 80 g/l of chromic anhydride. l,
Sulfuric acid o, 811, silicification:/-ta1 g/? (
7) In the mixed solution, cathode electrolysis treatment was performed under the conditions of a current density of 20 A/dm2 and an electrolyte temperature of 50°C, and immediately (180
It was washed with hot water at ℃ and dried. The amount of metallic chromium in the obtained electrolytic chromic acid treated steel sheet was 160 mg//rr
In I2, the hydrated chromium oxide is 22m9/r as chromium.
It was r12.

A biaxially oriented polyethylene terephthalate film treated under the following conditions was continuously laminated on both sides of the electrolytic chromic acid treated steel sheet under the following conditions.

M vapor deposition layer thickness 1.400 Dry weight of Evokin resin composition in the lower layer of AM vapor deposition layer 1.0 g/r11
2 Biaxially oriented polyethylene terephthalate film (trade name Lumirror Azuma) Dry weight a2. Heating method for og//rr+2 steel plate: Heater roll lamination, steel plate temperature immediately before lamination: 248°C Cooling method after lamination
Rapid Cooling A vinyl organosol paint was applied to both surfaces of the obtained M vapor-deposited resin-coated steel plate to a dry weight of 65 mg/m 2 , heat-cured at 190° C. for 10 minutes, and then slowly cooled.

The M vapor-deposited resin-coated steel sheet was heated to 202 mm by a known can-making method.
A molded can lid and a drawn can with a drawing ratio of 2.14 were obtained. Shaped squeeze can (- Filled with commercially available tomato juice, degassed, double sealed, heat sterilized at 115℃ for 60 minutes, 50℃
A 6-month real can storage test was conducted on C.

After the actual can test, the can was opened and the corroded state of the inner surface of the can and the adhesion of the biaxially oriented polyethylene terephthalate film were investigated, but no abnormalities were observed, and the can had a bright and beautiful appearance.

In addition, we conducted a storage test for 14 days in an atmosphere of 50°C and relative humidity of 9096°C, and investigated for filamentous rust or black rust near the double-sealed can lid, but no abnormalities were observed, and the beautiful M
It had color.

Comparative Example 2 Using the same electrolytic chromic acid treated steel plate as in Example 2, a 1''-vinyl organosol paint was applied to both sides of the plate with a dry weight of 65
After applying it to a concentration of mg/m2, it was applied at 190℃ for 10
After being heated and cured for a minute, it was slowly cooled.

The painted steel plate was processed in the same manner as in Example 2 to obtain a can lid and squeeze can, filled with tomato juice in the same manner as in Example 2, and subjected to a 6-month real can storage test at 50°C. I did it.

After the actual can test, the can was opened and the state of corrosion on the inner surface of the can was examined, and black rust was found in several places near the double seam of the drawn can and near the compound insertion part of the can.

In addition, when a storage test was conducted for 14 days at 50°C and a relative humidity of 909+5, a large number of filamentous rust 3 to 8 mm in length appeared near the double seam of the can lid, significantly deteriorating the appearance of the container. I was letting it go.

Example 3 A cold-rolled steel plate with a thickness of 0.21 mm is 70 g/I! After electrolytic degreasing in a sodium hydroxide solution, pickling with a 100 g/l sulfuric acid solution, washing with water, and drying with a dryer.

Biaxially oriented polyethylene terephthalate films treated under the following conditions were continuously laminated on both sides of the thus cleaned black plate under the following conditions.

M vapor deposited layer thickness 2.000 Dry weight of epoxy resin composition in the lower layer of AM vapor deposited layer 4.5 g/'rn
"Biaxially oriented polyethylene terephthalate film (product name Lumirror Azuma ■) Dry weight of epoxy resin composition in the lower layer of 16 μm biaxially oriented polyethylene terephthalate film 3.5ν Heating method for steel plate Heater roll method Temperature of steel plate immediately before lamination 240 Cooling method after lamination at °C Apply two coats of epoxy/phenol paint to both sides of the M vapor-deposited resin-coated steel sheet obtained by slow cooling so that the dry weight is 4 Q @ / dm2, and heat cure at 205 °C for 10 minutes. After letting
It was slowly cooled.

The M vapor-deposited resin-coated steel sheet was heated to 20 mm by a known can-making method.
A type 2 can lid and a squeezed can with a squeeze ratio of 2.14 were obtained. The formed squeeze can was filled with 0.5% saline and double-sealed, and then a storage test was conducted at 37° C. for 20 days.

After the actual can test, the can was opened and the corrosion state of the inner surface of the can and the adhesion of the biaxially oriented polyethylene terephthalate film were investigated, but no abnormalities were observed, and the shiny appearance of the can remained intact.

Further, the amount of iron eluted in the 0.596 saline solution after the actual can test was measured by atomic absorption spectrometry, and it was below the detection limit.

In addition, a storage test was carried out for 14 days at 37°C and relative humidity of 9096°C, and thread-like rust or black rust was investigated near the double-sealing of the can lid, and it was found that the thread-like rust was 2 to 3 mm near the double-sealing. Although it appeared, since it appeared in the lower layer of the M vapor deposition layer, it had the glittering property of M, which was quite beautiful in appearance.

Comparative Example 3 Example 3 was applied to both sides of the same black plate as Example 3.
After applying an epoxy/phenol paint, can lids and squeeze cans were prepared using the same can-making method as in Example 3, filled with 1596 saline solution, and double-wound. After tightening, a real can storage test was conducted at 37° C. for 20 days.

After the actual can test, the can was opened and the state of corrosion on the inside of the can was investigated. Red rust had developed over the entire inside of the can, and most of the paint film had peeled off from the base steel plate. In addition, a storage test was carried out for 14 days in an atmosphere of 90% relative humidity at 37°C, and filamentous rust or black rust was investigated.The filamentous rust was 5 to 24 carp long, and the can lid and squeeze can part C2. It appeared and had a markedly poor appearance. In addition, near the double seaming area, the paint film became black, and blackish brown rust appeared all over the surface.

〔Effect of the invention〕

The thus obtained M vapor-deposited resin coated steel sheet not only has an excellent appearance due to its brightness, but also has excellent processing corrosion resistance and
Because it has excellent processing adhesion, it can be widely used as a material for containers.

Claims (1)

[Claims] (1) The outermost layer has an Al vapor deposited layer of 50 to 3000 Å,
The inner layer contains epoxy resin and its curing agents such as phenol, urea, amide, ester, and acrylic.
It has a composition layer consisting of one or more types of urethane, the inner layer thereof is a biaxially oriented polyethylene terephthalate resin layer, the bottom layer is an epoxy resin, and its curing agent is phenol, urea, amide, A resin-coated steel sheet for containers comprising a composition layer consisting of one or more of ester-based, acrylic-based, and urethane-based.