JPH08174670A - Lamination method suppressing entrapment of air bubbles - Google Patents

Abstract

PURPOSE: To suppress entrapment of air bubbles when a resin film is laminated to a metal strip at a high speed by a press bonding roll. CONSTITUTION: A resin film 2 is laminated to a metal strip 1 by a press bonding roll 3 while air is ejected from one side end part of the metal strip 1 to the other side end part thereof along the gap of the press bonding start part generated between the resin film 2 and the metal strip 1 at flow velocity of 10-300m/sec in the lateral direction of the metal strip 1. The temp. of air to be ejected is equal to or higher than that of the metal strip 1 immediately before lamination but does not pref. exceed the temp. of the metal strip 1 by 50 deg.C or higher. It is also effective to arrange a guide plate 6 guiding jet air 5 along the gap of the press bonding start part generated between the resin film 2 and the metal strip 1.

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 laminate material used in the field of container materials, that is, a material obtained by laminating a resin film on a metal strip, in which bubbles are not caught between the resin film and the metal strip. .

[0002]

2. Description of the Related Art In the field of container materials, coated steel plates or aluminum plates are currently in the mainstream, but there is a trend toward legal regulation against environmental pollution caused by solvents.
Also, since there is a limit to the efficiency of the painting / baking process and energy saving, there is a trend in the future where a method of laminating a resin film on a flat plate as a method of using no solvent instead of painting, and then making a can and processing it is used. It is considered. That is, according to the resin laminating method, it is possible to prevent environmental pollution due to the solvent in the present painting / baking process, and to eliminate consumption of solvent volatilization energy. In particular, high-speed laminating can be mass-produced and can stably supply can manufacturing materials at low cost, and at the same time, the line speed of the plating line such as tin plating or tin-free plating (chromium plating) matches the laminating speed. Since the laminating equipment can be installed in the line, the manufacturing cost can be further reduced. Up to now, a laminate of a film and a metal foil as a packaging material or a multilayer laminate of a resin film has already been technically completed, and answers a lot of demands today. It is also beginning to be used in the field of food cans.

As a conventional laminating method, Japanese Patent Publication No. Sho 61-
Japanese Patent No. 3676 discloses a method of attaching an organic resin film to a steel strip. In this method, a tin-plated steel strip is preheated, a resin film is temporarily pressure-bonded thereto with a pressure-bonding roll, and then the temperature of the steel strip is increased to further pressure-bond the resin film with a pressure-bonding roll.

[0004]

The technique of high-speed laminating at a speed several times faster than painting is essential for inexpensive and stable material supply, but when a resin film is fed at high speed toward the surface of a steel strip. The air in the vicinity of the surface of the resin film may be carried along with the traveling of the resin film and brought into the pressure bonding portion. The air brought in remains as air bubbles between the steel strip and the resin film, and in the case of large air bubbles, it swells. Although this blister reduces the commercial value of the laminated steel strip, even if it is a microscopic bubble that does not feel like an external appearance, if it is subjected to canning processing such as drawing and ironing, the film adhesion after processing will be extremely poor, It is useless as a material for cans.

In order to prevent such entrainment of air bubbles, JP-A-63-233824 discloses that the resin film is fed toward the steel strip while maintaining the angle between the steel strip and the resin film at 30 to 90 degrees. A method of supplying and crimping with a crimping roll is disclosed. This method is understood to prevent the wedge effect of air-fluid, but the running speed of steel strip is 200m.
When high-speed laminating is performed at a speed of / min or more, bubble entrainment still occurs, and this measure is not sufficient.

As a more drastic measure, a method of placing the laminated portion in a vacuum state can be considered. As a vacuum apparatus used for this, a continuous vacuum vapor deposition apparatus for zinc plating is already well known. This is a so-called air-to-air system in which the steel strip coil of the material is in the atmosphere and undergoes multiple stages of differential pressure reducing chambers before reaching the vacuum deposition chamber, which has already been used in commercial production. However, the use of this vacuum device for lamination has the following drawbacks.
That is, when the film is introduced from the atmosphere into the vacuum chamber, the film is sandwiched by the multi-stage seal rolls, so that the film is likely to be excessively tensioned. Since the film is softened or partially melted at the pressure-bonded portion, it cannot withstand this excessive tension, and the film is easily broken. Further, although the speeding up of the lamination is performed for the economical advantage, the vacuum device is generally expensive and the economic merit due to the speeding up is offset.

Further, when laminating a steel strip or an aluminum strip traveling at a high speed, it is possible to reduce air bubble entrainment by increasing the rolling force of the pressure-bonding roll, but when the traveling speed of the metal strip is increased, the air bubble entrainment amount is increased. Therefore, the rolling force also needs to be increased accordingly. However, at a high laminating speed of 200 m / min or more, even if the rolling force is increased to a load of 100 kgf per 1 cm width of the metal strip, the effect is saturated as the pressure becomes higher, and it is difficult to obtain a sufficiently low bubble area ratio. Is.

Therefore, the present invention provides an economical method for suppressing bubble entrainment during high-speed lamination.

[0009]

According to the present invention, when a resin film is laminated on a metal strip through a pressure roll, one of the metal strips is formed along the void at the pressure-bonding start portion generated between the resin film and the metal strip. A laminating method for suppressing bubble entrapment, characterized in that a gas is jetted in a width direction of a metal strip from one width end to the other width end at a flow rate of 10 m / sec or more and 300 m / sec or less. It is preferable that the temperature of the gas to be jetted is equal to or higher than the temperature of the metal strip just before laminating and does not exceed 50 ° C. higher than the temperature of the metal strip. Further, it is also effective to install a guide plate for guiding the jet gas along the gap of the pressure-bonding start portion generated between the resin film and the metal strip.

[0010]

The present invention will be described in detail below.

Air accompanying the surface of the metal strip running at a high speed collides toward the pressure-bonded portion of the film and the metal strip, causing air bubbles to be entrained. Therefore, it is important to remove the accompanying flow of air near the pressure-bonded portion. is there. Therefore, in the present invention, the ejector effect in which the pressure is reduced in the vicinity of the high-speed air flow is used. That is, as shown in FIG. 1, in order to effectively reduce the pressure in the vicinity of the crimping portion, gas is blown along the vicinity of the crimping portion from the side surface of the metal strip 1 in the direction perpendicular to the running direction, that is, in the width direction of the metal strip 1. Is injected at high speed. The flow velocity of the jet gas 5 has a lower limit of 10 m / sec and an upper limit of 300 m / sec. When the flow velocity of the jet gas in the laminate traveling at 300 m / min is less than 10 m / sec, the bubble area ratio exceeds 5% and exceeds the practical allowable limit of 1%. The effect is saturated when the flow velocity of the jet gas exceeds 300 m / sec.
Regarding the allowable limit of the bubble area ratio, Table 1 shows the ERV (enamel lator value) after rolling the laminated steel sheet in consideration of the bubble area ratio and the reduction in plate thickness during can making. ERV represents the degree of pinholes in the film as a current value. From Table 1, it is clear that if the bubble area ratio is 1% or less, the problem of pinholes does not practically occur.

[0012]

[Table 1]

If the temperature of the jet gas is room temperature, the temperature of the metal strip is lowered by the jetting. Therefore, it is necessary to measure the temperature of the metal strip at the time of lamination and preliminarily give the temperature of the reduced amount to the metal strip. This is not necessary if the temperature of the jet gas is adjusted to the temperature of the metal strip during lamination. However, if the temperature exceeds 50 ° C. above the metal band temperature during lamination, the film will be melted, which is not preferable.

Although various gases such as air and nitrogen can be used as the jet gas, air or nitrogen is preferable because it is practically inexpensive and abundant. Since the jet gas tends to diffuse after being jetted from the nozzle, if the guide plate 6 as shown in FIG. 2 is installed in order to concentrate the jet gas in the vicinity of the pressure-bonded portion, the effect of the jet gas is further improved. The type, installation method, installation position, etc. of the guide plate may be determined as appropriate.

The angle formed by the resin film and the metal strip is preferably 90 ° or more in order to prevent the jetted gas from entering between the metal strip and the resin film, but is limited to this angle if a guide plate is installed. do not have to.

As the metal strip, a steel strip such as a plated original sheet, a tin-plated steel sheet, a nickel-plated steel sheet, an electrolytic chromic acid-treated steel sheet (tin-free steel), an aluminum-plated steel sheet or an alloy-plated steel sheet thereof, an aluminum plate for a can (3
Aluminum strip of No. 000 series, No. 5000 series alloy) can be used. As the heat-bondable resin film, polyethylene terephthalate, polybutylene terephthalate,
Polyester resin such as polyethylene isophthalate,
It is preferable to use an acid-modified polyolefin resin that is an acid-modified product such as polyethylene or polypropylene, or a polyamide resin such as nylon. The temperature of the metal strip at the time of thermocompression bonding is set near the melting point of the resin film to be laminated, and the thermocompression bonding method may be an ordinary method of applying heat from the metal strip toward the resin film. Further, so-called dry laminating in which laminating is performed via an adhesive is also possible.

[0017]

EXAMPLES Examples will be described below.

Lamination was performed using the apparatus shown in FIGS. 1 and 2. An electrolytic chromic acid-treated steel plate having a plate width of 500 mm is used as the metal strip 1, and PET (polyethylene terephthalate, melting point 265 ° C.) is used as the resin film 2;
At a plate temperature of 0 ° C., the pressing force of the press roll 3 was pressed at 90 kgf per 1 cm width of the steel plate.

While measuring the bubble area ratio of the laminated plate obtained by changing the kind of the jet gas 5, the jet flow velocity and the temperature, the influence of the presence or absence of the guide plate 6 shown in FIG. 2 was investigated and the results are shown. 2 shows. From Table 2, when the flow velocity of the injected gas is 0 ° C. and 10 m / sec at 1 atmospheric pressure, the bubble area ratio is 1%.
It can be seen that the following is obtained. Further, when the temperature of the jet gas is near the plate temperature of the steel strip during lamination, it is also effective in suppressing the bubble area ratio. Furthermore, the effect of the guide plate was also obtained. Examples of air and nitrogen were shown as gases, but there was no difference between them.

[0020]

[Table 2]

In this example, PET having a melting point of 265 ° C. was pressure bonded at a pressure bonding temperature of 260 ° C. Polybutylene terephthalate having a melting point of 230 ° C., nylon 6 having a melting point of 215 ° C., and melting point of 18 were used.
The 8 ° C. acid-modified polypropylene was also laminated at the respective melting points minus 5 ° C. for the pressure bonding temperature, and the same results as in Table 2 were obtained. Further, the same results as in Table 2 were obtained when a tin-plated steel strip, a plated original sheet, a nickel-plated steel strip or an aluminum strip for cans was used.

[0022]

According to the present invention, it is possible to suppress air bubble entrainment during high speed lamination.

[Brief description of drawings]

FIG. 1 is a diagram showing a laminating method of the present invention.

FIG. 2 is a diagram showing a situation in which a guide plate is installed by the laminating method of the present invention.

[Explanation of symbols]

 1 Metal Band 2 Resin Film 3 Crimping Roll 4 Gas Injection Nozzle 5 Injection Gas 6 Guide Plate

Claims (3)

[Claims] 1. When laminating a resin film on a metal strip through a pressure roll, one width end of the metal strip to the other width end of the metal strip along a gap at a pressure-bonding start portion generated between the resin film and the metal strip. Gas per second in the width direction of the metal strip toward the part
A laminating method in which bubble entrainment is suppressed, characterized by spraying at a flow rate of 0 m or more and 300 m / sec or less. 2. The temperature of the gas to be jetted is equal to or higher than the temperature of the metal strip immediately before laminating and is 50 ° C. higher than the temperature of the metal strip.
The method of laminating according to claim 1, wherein the entrainment of air bubbles is suppressed. 3. The laminating method according to claim 1 or 2, wherein a guide plate for guiding a jet gas is installed along a gap at a pressure-bonding start portion generated between the resin film and the metal strip. .