JPH0760841A - Real time detecting method for mixture of foreign matter at time of laminating - Google Patents

Abstract

PURPOSE:To real time control regulation of laminating atmospheric conditions for preventing winding of a foreign matter by continuously measuring a conducting point of a laminating metal band after press-bonding during feeding when a resin film is continuously press-bonded to be laminated on both or one surface of the band. CONSTITUTION:In order to press-bond to laminate a metal band 9 on a film 8 by a laminating roll 7, a ground roll 1 is disposed before laminating, a water- cooled tank 5 and a drying furnace 6 are provided after laminating, and high voltage and insulating liming roll 3, 4 are disposed on the rear surfaces. When a foreign matter on a front surface is detected, a current leakage 10 between the rolls 3 and l is measured. When an electrostatic capacity of a rear surface is measured, a current leakage 11 between the rolls 4 and 1 is measured. A pressing rubber roll 2 is disposed on an opposite surface of the roll 3, and a film surface is brought into close contact with the roll 3 to completely detect the matter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting, in real time, foreign matter such as dust mixed in a laminated film when a resin film is laminated on a metal strip.

[0002]

2. Description of the Related Art In the container field, coated steel sheets or aluminum sheets are currently in the mainstream, but there is a trend toward legal regulation against environmental pollution caused by solvents, and the efficiency of painting and baking processes. Since there is a limit to the improvement of energy consumption and energy saving, it is considered that a method of laminating a resin film on a flat plate instead of painting and then using it for can making and processing will become a trend in the future.

The conventionally known laminate material of film and metal foil or multilayer laminate material of resin film, so-called soft packaging material has already been technically completed and has met a lot of demands today, but it is so-called for food cans. It has not yet been applied to the field of can materials.

At present, a method of laminating a resin film on a steel plate or an aluminum plate as a base and thereafter making a can is being developed.

In the development, in order to guarantee the soundness of the film after the can-making process, it is a major problem to completely eliminate the inclusion of foreign matter in the laminated plate.

[0006] As a conventionally known laminating method, for example, in Japanese Patent Publication No. 6-3676, a tin-plated steel strip is preheated, a resin film is preliminarily pressure-bonded thereto with a pressure roll, and then the steel strip is heated. There is disclosed a method of further press-bonding the resin film with a press-bonding roll.

When the resin film is fed toward the surface of the steel strip in the above-described method, air in the vicinity of the surface of the resin film may be accompanied by the traveling of the resin film and brought into the crimping portion. Suspended dust may be contained in the air brought in.

The dust enters between the steel strip and the resin film or between the resin film and the pressure bonding roll and becomes trapped in the resin film.

Such foreign matters not only lower the commercial value of the laminated steel strip, but generally, even if they are minute foreign matters which are invisible to the naked eye, they are generally bent, drawn, ironed,
When subjected to can forming processing such as flange forming, the film integrity (pinhole) after processing is remarkably inferior and it cannot be used as a material for cans.

In order to prevent such entrapment of foreign matter, means for cleaning the atmosphere of the laminate manufacturing equipment, cleaning the surface of the laminate roll with an adhesive roll, preventing film static electricity, etc. are well known and have already been achieved. There is.

[0011]

In the above method, there is no disclosure of means for detecting the entrapment of a foreign substance in real time.

Therefore, it cannot be said that the quality of the laminated material produced is incomplete. This becomes a problem especially in high-speed production.

That is, at present, a practical measuring method is a means for cutting off a very small part of the produced laminated product and observing it with a microscope. With this method, it is impossible to check the quality of the entire width and length of the product.

Further, as the laminating speed becomes faster, it becomes more difficult to detect the foreign matter. Therefore, it is inevitable that it is necessary to measure the entrainment of the foreign matter in real time to adjust the reject of the foreign matter portion and the laminating atmosphere.

However, since there is no real-time detection method yet, the work of actual production is difficult.

[0016]

Means for Solving the Problems The inventors of the present invention detect in real time the foreign matter caught between the metal strip and the film or the foreign matter caught between the film and the pressure roll when laminating the metal strip and the resin film. As a result of various studies, the following method was found.

That is, the present invention is as follows: (1) When a resin film is continuously crimped and laminated on both sides or one side of a running metal strip, the current-carrying point of the laminated metal strip after crimping is continuously measured during running. A real-time detection method for foreign substances mixed in during lamination.

(2) In the current-carrying point measurement described in (1),
Before laminating, contact the metal strip and the earth roll, and after laminating, contact the measurement film surface of the laminated metal strip and the insulating lining roll to which high voltage is applied,
Insert it with a rubber lining roll from the opposite side and press down,
A real-time detection method for foreign matter contamination during lamination, which is characterized by continuously measuring an energization point between the earth roll and the high-voltage applying roll. Is the gist.

The present invention will be described in detail below.

The metal strip used in the present invention is a plated original plate, a tin-plated steel plate, a nickel-plated steel plate, an electrolytic chromic acid-treated steel plate (Tein-free steel), an aluminum-plated steel plate and alloy-plated steel plates thereof, aluminum and aluminum alloy plates, etc. To use. As the heat-bondable resin film, polyester resin (polyethylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, etc.), acid-modified polyolefin resin (polyethylene, polypropylene, etc.), polyamide resin (nylon, etc.), polyacrylonitrile, etc. are used.

Further, so-called dry laminating for laminating these resin films with an adhesive is also within the scope of the present invention.

The real-time detection of the above-mentioned foreign matter caught between the metal strip and the film or foreign matter caught between the film and the pressure-bonding roll is carried out by applying a current or current between the metal band before the pressure-bonding and the laminated metal band after the pressure-bonding. Judge by the occurrence of leak.

The principle is as follows. That is, the dielectric breakdown voltage of the resin film decreases as the thickness of the resin decreases.

On the other hand, in the portion where the foreign matter is caught, the thickness of the resin is smaller than that in the normal portion, and the dielectric breakdown occurs in the foreign matter portion even at a voltage at which the normal portion does not cause dielectric breakdown.

In reality, there are cases where the foreign matter remains in the state of being caught, and cases where the foreign matter has already been removed after being caught.

In the latter case, since the insulation voltage of air is sufficiently smaller than that of the resin film, it can be detected by this method.

Further, in the former case, as is understood from the fact that high-voltage electric equipment (for example, a transformer) is regularly cleaned, floating dust generally lowers the insulation resistance and can be detected by this method.

Since this detection method is particularly sensitive to metallic foreign substances, it is effective in an environment where there are many metallic dust foreign substances, such as in the steel industry.

According to the method of the present invention, it is not necessary to cut a sample from the laminate material, and the foreign matter entrapment portion can be detected simultaneously with the laminating operation.

The detected portion can be marked at the same time with a non-contact type marker such as an ink jet, and can be rejected during can making.

Therefore, the quality of the entire width and the entire length can be guaranteed, and since it is possible to detect in real time while laminating, the laminating conditions can be reflected in real time even when laminating at high speed, and the actual work can be stably performed.

An example of the measuring device is shown in FIG. In order to press and laminate the metal strip 9 and the film 8 with the laminating roll 7, the earth roll 1 is arranged before laminating, the water cooling tank 5 and the drying oven 6 are provided after laminating, and the high voltage / insulating lining roll is provided on the rear surface thereof. Place 3 and 4.

When detecting a foreign matter portion on the front surface, the current leak 10 between the detection roll 3 and the earth roll 1 is measured.

On the other hand, when measuring the electrostatic capacity of the back surface, the current leak 11 between the detection roll 4 and the earth roll 1 is measured. Further, as shown in the example of FIG. 2, the rubber roll 2 for reduction is arranged on the opposite surface of the detection roll 3.

This is because the film surface is brought into close contact with the detection roll 3 in order to detect the foreign matter completely and completely. The rolling force may be any constant value and is not particularly specified.

The metal strip is often subjected to a surface treatment. For example, a steel plate treated with electrolytic chromic acid has an insulating film of hydrated chromium oxide on the surface.

In this case, even if the earth roll is pressed against the surface treated with electrolytic chromic acid, it is difficult to obtain the earth, which may hinder the detection of dielectric breakdown.

In order to solve this, as shown in FIG. 1, the earth roll 1 is configured to be pressed from the side surface to the end portion (ear portion) in the width direction of the metal band.

This is to utilize the fact that the insulating film of hydrated chromium oxide is removed and the base iron is exposed in order to trim excess ears of the metal strip after electrolytic chromic acid treatment. With this structure, sufficient ground can be secured.

The present invention will be described below based on examples.

[0041]

EXAMPLES The metal strips used in the examples are steel strips treated with electrolytic chromic acid. As a typical laminated film, polyethylene terephthalate having a thickness of 20 μm was used. The laminating apparatus used is that shown in FIG.

The temperature of the steel strip during the pressure bonding of the laminate was 250 ° C. The pressing force of the laminating roll was 50 kg per 1 cm of the width of the laminating film. The laminating speed is as shown in Table 1.

The foreign matter was separately sampled and the particle size was divided and artificially inserted between the film and the pressure roll or between the steel plate and the film. The film surface depression was made by inserting iron powder and then dissolving the iron powder with hydrochloric acid.

As a comparative example, Table 1 shows the results of detecting the inclusion of foreign matter by the conventional microscopic observation.

From the results shown in Table 1, it can be seen that the foreign matter detection rate of the laminate film by the real-time detection of the present invention is better than the detection rate by the conventional microscopic observation.

Table 2 shows the relationship between the thickness of polyethylene terephthalate and the dielectric breakdown voltage. Since the dielectric breakdown voltage differs depending on the type of laminate film, the voltage should be determined in advance for each type and thickness of film. This is a measurement method that can be practically used if used.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

According to the real-time foreign matter entrapment detection method of the present invention, it is possible to perform 100% inspection over the entire width and the entire length while laminating at high speed, and it is also possible to adjust the lamination atmosphere condition for preventing foreign matter entrapment during laminating work. Real-time control is possible, which can contribute to product quality assurance and a significant improvement in product yield.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a measuring method of the present invention.

FIG. 2 is an explanatory diagram showing a contact state between a detection roll and a rubber roll for reduction.

[Explanation of symbols]

 1 Earth roll 2 Rubber roll for reduction 3 Detection roll 4 Detection roll 5 Water cooling tank 6 Drying furnace 7 Laminating roll 8 Resin film 9 Metal band 10 Leak current between 1 and 3 11 Leak current between 1 and 4 12 Nip width

Claims (2)

[Claims] 1. A laminate characterized by continuously measuring the current-carrying point of a laminated metal strip after pressure bonding when laminating a resin film on both sides or one side of a running metal strip by continuous pressure bonding. A real-time detection method for foreign matter contamination. 2. The current-carrying point measurement according to claim 1, wherein a metal strip and an earth roll are brought into contact with each other before lamination, and a measurement film surface of the laminate metal strip is brought into contact with an insulating lining roll to which a high voltage is applied after lamination. A real-time detection method of foreign matter mixing during lamination, characterized by continuously measuring the energization point between the earth roll and the high-voltage applying roll by sandwiching and pressing down with a rubber lining roll from the opposite surface.