JP3190243B2 - Laminating method with controlled atmosphere and laminated metal strip thereby - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas applied between a resin film and a metal band when manufacturing a laminate material applied to container materials, home appliances, and building materials, that is, a material obtained by laminating a resin film on a metal band. effectively reducing the volume relates to a method and laminated metal strip by which to lamination.

[0002]

2. Description of the Related Art In the field of container materials, home appliances, and building materials, coated steel sheets or aluminum sheets are currently the mainstream. However, environmental pollution due to solvents is being regulated by law.・ Because there is a limit to the efficiency of the baking process and the energy saving, there is a possibility that the method of laminating a resin film on a flat plate as a method without using a solvent instead of painting and then processing and using it will be the future trend. ing. Up to now, a laminate of a film and a metal foil or a multilayer laminate of a resin film as a packaging material has already been technically completed and is meeting many demands today. It is also beginning to be applied to the field of food cans. Furthermore, also in the field of building materials, laminated metal plates have been put to practical use.

[0003] As a conventionally known laminating method, as disclosed in Japanese Patent Publication No. 61-3676, an organic resin film is bonded to a steel strip. In this method, a tin-plated steel strip is preheated, and a resin film is temporarily press-bonded thereto by a pressure roll, then the steel strip is heated, and the resin film is further pressure-bonded by a pressure roll.

[0004]

Process technology for high-speed lamination at several times the speed of painting is indispensable for inexpensive and stable material supply, but resin film is fed at high speed to the steel strip surface. At this time, the air in the vicinity of the surface of the resin film may be brought into the crimping portion as the resin film travels. The introduced air remains as bubbles between the steel strip and the resin film, and when the bubbles are large, they blister.

Although it is obvious that the blisters reduce the commercial value of the laminated steel strip, even if the bubbles are small enough not to be felt in the appearance, they can be subjected to canning such as drawing and ironing after the processing. The film adhesion is remarkably inferior, and it is not used as a material for cans. Also, in the case of building materials, severe bending processing causes defects in the coating. To prevent such air bubble entrapment, Japanese Patent Application Laid-Open
No. 233824 discloses a method in which a resin film is fed toward a steel strip and pressed by a pressure roll while maintaining the angle between the steel strip and the resin film at 30 to 90 degrees. Although this method is understood to prevent the wedge effect of the air fluid, when high-speed lamination is performed at a running speed of the steel strip of 200 m / min or more, air entrapment still occurs, and this measure is insufficient.

[0006] Further, as a drastic method, a method of evacuating the laminating section can be considered, and many such publications are already known as continuous vacuum evaporation apparatuses for zinc plating. This is the material (steel strip coil)
Is a so-called air-to-air system which is in the atmosphere and passes through a multi-stage differential pressure reducing chamber before reaching a vacuum evaporation chamber, and has already been used for commercial production.

However, when this vacuum apparatus is applied to a laminate, there are the following problems. When the film is introduced into the vacuum chamber from the atmosphere, excessive tension is likely to be applied to the film because the film is sandwiched by the multi-stage seal rolls. further,
Since the film is softened or partially melted in the pressure-bonded portion, the film cannot withstand the excessive tension and the film is easily broken. In addition, the speeding up of the lamination is performed for economic merit, but the vacuum device is generally expensive, so that the economic merit of the speeding up is offset.

Accordingly, an object of the present invention is to provide an economical laminating method capable of suppressing the air entrainment volume at a high speed during lamination, and a laminated metal strip thereby .

[0009]

Means for Solving the Problems In the method of high-speed laminating a resin film to a metal strip, the present inventors have studied various measures for reducing the volume of bubbles involved, and have reached the present invention based on the obtained knowledge. That is, in the present invention, the atmosphere at the pressure-compression starting portion when laminating the resin film to the metal strip is a gas having a molecular weight of 44 or less (excluding air), and the concentration is 50% or more as a volume ratio. This is a laminating method in which the characteristic atmosphere is controlled. It is preferable that the gas has a permeability coefficient of three times or more that of nitrogen gas in the laminate resin. Specifically, the gas is
Any one of carbon dioxide gas, helium gas, hydrogen gas, oxygen gas, and water vapor, or a mixed gas of two or more thereof is preferable.

The present invention also relates to a laminated metal strip produced by the laminating method, wherein a gas having a molecular weight of 44 or less (excluding air) is preferably provided in a gap between the resin film and the metal strip. In addition, it is a laminated metal strip whose permeation coefficient in the laminated resin is three times or more that of nitrogen gas and whose concentration is contained by 50% or more by volume.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. As a result of various investigations on the type of gas of the gas bubble sealed when the resin film is laminated at a high speed on the metal strip, a gas having a high permeation rate in the resin film, that is, a gas having a molecular weight of 44 or less, preferably nitrogen It has been found that a gas species having a permeability coefficient of 3 times or more, desirably 10 times or more, such as carbon dioxide gas, helium gas, hydrogen gas, oxygen gas, and water vapor, should be used.

Gases that easily pass through resins having a molecular weight of more than 44 include cyclohexane, benzene, toluene and carbon tetrachloride, which are organic vapors and have a problem of odor due to food taste or building materials. Difficult to use. Therefore, it is preferable to control the atmosphere of the pressure-bonded portion with a gas having a molecular weight of 44 or less and having a permeation speed in the laminate resin larger than the nitrogen gas as described above. For this purpose, as a method of controlling the atmosphere of the crimping section, a normal box-type seal box as shown in FIG. 1 may be applied. Preferably, the gas ejected to the inner box is formed as a double structure and the outer box is sealed. To improve the atmosphere sealing property.

In this way, when controlling the atmosphere at the start of the lamination pressure bonding, the effect of the concentration of the gas to be sealed in the bubbles is exhibited at 50% or more. In comparison, since it is about 1/2, there is no defect at the time of can making as an example of severe processing. In addition, the upper limit of the concentration is not particularly specified, but in order to set the maximum concentration to 100%, the sealing mechanism is prevented from becoming complicated and expensive equipment.
For example, it may be about 95%.

The temperature of the gas is from room temperature to preferably 200
It is preferable to add the effect of volume shrinkage upon cooling by heating to about ° C, but there is no particular drawback even at room temperature. Note that the gas pressure may be normal pressure.

The metal strip used in the present invention includes a base plate, a tin-plated steel plate, a nickel-plated steel plate, an electrolytic chromic acid-treated steel plate (tin-free steel), a galvanized steel plate, an alloyed galvanized steel plate, and a lead-tin plated steel plate. A steel strip such as a steel sheet, an aluminum-plated steel sheet, or an alloy-plated steel sheet thereof, or an aluminum strip of an aluminum plate (for example, a 3000 series or 5000 series alloy) can be used. Examples of heat-adhesive resin films include polyester resins (polyethylene terephthalate, polybutylene terephthalate, copolymers of these isophthalates, etc.) and acid-modified polyolefin resins (acid modified products such as polyethylene, polypropylene, and copolymers thereof). It is preferable to use polyamide resin (eg, nylon), polyvinyl alcohol, polyacrylonitrile, polystyrene, or the like.

The temperature of the steel plate or the temperature of the aluminum plate at the time of thermocompression bonding is set to be close to the melting point of the resin film to be laminated, and the thermocompression bonding method may be a conventional method of applying heat from the steel band or aluminum band toward the resin film. Also, so-called dry lamination in which lamination is performed via an adhesive is within the scope of the present invention.

The laminated metal strip produced by the laminating method of the present invention as described above is characterized in that the gas having a molecular weight of 44 or less is contained alone or in a mixture of two or more gases in bubbles generated between the resin film and the metal strip. As volume ratio 5
Include at a concentration of 0% or more.

Such a laminated metal band has a property that gas in bubbles is transmitted through a resin film during production or as time passes after production. In this case, the phenomenon of breakage of the film due to the remaining bubbles as in the conventional case is avoided, and a good laminated can body can be obtained.

[0019]

The present invention will be described below with reference to examples. FIG. 1 shows an example of a schematic diagram of a laminating apparatus provided with an atmosphere seal box for carrying out the method of the present invention. Atmosphere seal box 4 is installed so as to surround 3 '.

A resin film was laminated on a metal plate using the above apparatus. As the metal plate 1, electrolytic chromic acid-treated steel plate is used, and as the resin films 2, 2 ', PE is used.
T (polyethylene terephthalate) was laminated at a plate temperature of 260 ° C.

At this time, the type of gas in the seal box,
Lamination was performed with the concentration changed as shown in Table 1, and the resulting cell area ratio was also shown in Table 1.
Since the cell area ratio depends on the melt thickness of the laminate film, the cell area ratio was measured after holding at 260 ° C. for 1 minute in order to obtain a constant melt thickness.

With respect to Nos. 1 to 9 of the present invention, a bubble area ratio of 1.0% or less was obtained under high-speed lamination, which was not a problem during can-making. From Table 1, it can be seen that the gas in the bubbles permeated during the lamination step or left in the atmospheric pressure atmosphere, the internal pressure of the bubbles decreased, and the volume of the bubbles shrank.

When a gas having good permeability to the laminate film is entrapped as bubbles as described above, the internal pressure of the bubbles is reduced during the laminating step or standing in the air, and when the laminated plate is processed into a can, It can be harmless. Also, with the increase in laminating speed,
The gas entrainment volume increases, but the bubble volume shrinks to a certain level (harmless level) if the rolling force is increased in accordance with the increase in laminating speed. This is not a problem when making cans. As a result, a good laminated can is obtained.

The reason why it has been determined that if the cell area ratio measured as described above is 1.0% or less does not cause any problem during can making will be described below. The relationship between the bubble area ratio and the characteristics of the can was investigated, and the results are shown in Table 2. At this time, the can-making characteristics were as follows: after rolling was performed from the viewpoint of the processing rate, the electrode was placed between the electrode and the sample via a 0.5% saline solution.
A current value (ERV) when a voltage of V was applied was measured. From Table 2, it can be seen that if the bubble area ratio is 1% or less, ERV becomes 0.

Further, as an example of processing, it is referred to as can making, but this is not limited to the container field, and it is also used in home appliances and building materials through similar processing steps. Will be similarly processed.

In Tables 1 and 2, polyethylene terephthalate (melting point: 265 ° C.) was applied at a compression temperature of 260 ° C., and polybutylene terephthalate (melting point: 230 ° C.) was used.
° C), nylon 6 (melting point 215 ° C), acid-modified polypropylene (melting point 188 ° C), acid-modified low-density polyethylene (melting point 120 ° C), polyacrylonitrile (melting point 317).
C), polyvinyl chloride (melting point 210 ° C.), and isotactic polystyrene (melting point 230 ° C.) were laminated at the compression temperature at each melting point, and the same results as in Tables 1 and 2 were obtained. Furthermore, in Tables 1 and 2, electrolytic chromic acid-treated steel sheets having a width of 500 mm were used as materials, but tin-plated steel strips (in the case of tin plating, a resin having a melting point of tin or less is used),
Base plate, nickel-plated steel strip, galvanized steel strip, galvannealed steel strip, lead-tin plated steel strip, aluminum-plated steel strip, zinc-iron alloy-plated steel strip, zinc-nickel alloy-plated steel strip or aluminum strip Was used, the results were the same as in Tables 1 and 2. In addition, when a plurality of rolling roll devices were used as the rolling device, the same results as in Tables 1 and 2 were obtained by cooling immediately after pressing.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

According to the resin laminating method of the present invention, there is no risk of environmental pollution due to the solvent in the coating and baking steps, and the consumption of solvent evaporation energy can be eliminated. In particular, in the high-speed laminate according to the present invention, can-stock material can be stably supplied at a low cost and can be mass-produced,
Since the line speed of the plating line such as tin plating or tin-free plating (chrome plating) matches the laminating speed, a laminating facility can be installed in the plating line, so that the production can be performed at lower cost. And, according to the laminated metal strip manufactured by the method of the present invention, even if gas is entrapped as bubbles, it can be made harmless at the time of can making process, so that a good laminated can body is made, The rate of can making is improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an atmosphere sealing device to which a laminating method of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal plate 2, 2 'Resin film 3, 3' Crimping roll 4 Atmosphere seal box

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yachi Oyagi 1-1, Hibata-cho, Tobata-ku, Kitakyushu-shi, Fukuoka Prefecture Nippon Steel Corporation Yawata Works (56) References JP-A-5-269857 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 65/00-65/82 B32B 1/00-35/00

Claims (6)

(57) [Claims] 1. An atmosphere at a pressure start portion when laminating a resin film on a metal strip is a gas having a molecular weight of 44 or less (excluding air), and its concentration is 50% or more as a volume ratio. Lamination method with controlled atmosphere. 2. The laminating method according to claim 1, wherein the permeability coefficient of the gas in the laminating resin is at least three times that of the nitrogen gas. 3. The method according to claim 1, wherein the gas is carbon dioxide gas, helium gas,
3. A gas according to claim 1, wherein the gas is a single gas selected from the group consisting of hydrogen gas, oxygen gas, and water vapor, or a mixed gas of two or more of them.
A lamination method in which the atmosphere described is controlled. 4. A laminated metal strip comprising a gas having a molecular weight of 44 or less (excluding air) in a gap between the resin film and the metal strip in a concentration of 50% or more by volume. 5. The laminated metal strip according to claim 4, wherein a permeability coefficient of the gas in the laminated resin is at least three times that of the nitrogen gas. 6. The method according to claim 1, wherein the gas is carbon dioxide gas, helium gas,
6. A gas as a single gas or a mixed gas of two or more of hydrogen gas, oxygen gas, and water vapor.
The described laminated metal strip.