JPH05269857A - Laminating method - Google Patents

Abstract

(57) [Summary] [Purpose] Prevents entrapment of bubbles during high-speed lamination of laminated steel plates or aluminum plates for containers. [Structure] When laminating a resin film on both or one side of a running steel strip or aluminum strip by thermocompression bonding, the surface roughness of the steel strip or aluminum strip should be 0.5 micron or less as an average roughness A pair of seal rolls for sandwiching the steel strip is provided, and an intermediate roll is disposed in close contact between the roll and a pair of pressure rolls, and a resin film is sandwiched between the pressure rolls and the intermediate rolls.
The space surrounded by the seal roll, the intermediate roll and the pressure roll is depressurized to 50 TORR or less. [Effect] By combining with a steel strip under reduced pressure and a low roughness steel strip, it is possible to prevent entrapment of bubbles during lamination.

Description

Detailed Description of the Invention

[0001]

[Industrial application] In the field of container materials, coated steel sheets or aluminum sheets are currently in the mainstream, but there is a direction for legal regulation against environmental pollution by solvents, and coating / baking processes. Since there is a limit to the efficiency improvement and energy saving of the method, it is considered that a method of laminating a resin film on a flat plate instead of painting instead of painting and then using it for can making processing will become a trend in the future. ..

Up to now, a laminate of a film and a metal foil as a packaging material or a multilayer laminate of resin films has already been technically completed and has met a lot of demands today.
It has not yet been applied to the field of food cans.

At present, it is considered to laminate a resin film using a steel plate or an aluminum plate as a base and then to make a can, but it is in the process of development in recent years, and it is technically incomplete.

In particular, the process technology of laminating at high speed by several times as much as painting is indispensable for inexpensive and stable material supply, but it is a big problem to entrain air between a steel plate or an aluminum plate and a resin film at the time of high-speed laminating. Relates to prevention of air entrapment during high-speed lamination.

[0005]

2. Description of the Related Art As a conventionally known laminating method, Japanese Patent Publication No. 61-3676 discloses that an organic resin film is attached 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 roll, and then the temperature of the steel strip is raised to further main-bond the resin film with a pressure roll. ing.

Japanese Patent Application No. 61-183437 discloses a method of sequentially laminating an adhesive resin film and an aluminum foil on a steel strip.

In this method, the resin film and the aluminum foil are attached to the preheated running steel strip at different positions by pressure bonding rolls to form a laminated steel strip.

[0009]

As described above, when the resin film is fed toward the surface of the steel strip, the air in the vicinity of the surface of the resin film is accompanied by the traveling of the resin film,
May be brought to the crimp section.

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 blisters.

This blister reduces the commercial value of the laminated steel strip, but even with minute air bubbles that do not seem to be visible, if it is subjected to can making processing such as drawing and ironing, the film adhesion after processing will be extremely poor and the can can. It is useless as a material.

In order to prevent such entrainment of bubbles, in JP-A-63-233824, 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 crimping with a crimp roll is disclosed.

This is understood to prevent the wedge effect of air fluid, but when high speed laminating at a steel strip running speed of 200 m / min or more is performed, air entrainment still occurs,
This measure is not enough.

As a more drastic solution, it is easy to consider removing air or gas from the pressure-bonded portion to reduce the pressure.

As an example of this, in Japanese Patent Laid-Open No. 63-118241, a decompression chamber is provided on the upstream side of the pressure roll, and the inside is decompressed to 100 to 200 Torr by a vacuum pump.

The inlet side of the decompression chamber is sealed by a seal roll, and the outlet side is sealed by a pressure roll and a seal roll.

The metal foil and the carrier film are laminated in this decompression chamber to obtain an electric laminate without entrapment of bubbles.

When such a method is applied to a resin film laminating on a steel strip or an aluminum plate, if the traveling speed of the steel strip is 200 m / min or more, it cannot be visually discerned, but severe processing such as drawing and ironing is added. Entrapment of minute air bubbles that cause peeling occurs.

The surface roughness is artificially applied to ordinary steel strips or aluminum plates, and the surface roughness is not affected at low speeds, but the air present in the recesses of roughness at high speeds is a decompression chamber. It is considered that this is the result of crimping without being sufficiently diffused.

Further, in the field of vacuum vapor deposition, a technique for vapor deposition of aluminum on a film or vapor deposition of zinc on a steel strip has been widely disclosed today, but since a high vacuum of 0.1 Torr or less is required, the vacuum chamber has a multistage difference. Either a dynamic decompression chamber is provided at the front or rear, or the entire apparatus including the processing material coil is evacuated in a batch system.

When such a method is applied to laminating a resin film on a steel strip, air entrainment can be sufficiently prevented even at high speeds, but in actual operation foreign matter adhering to the steel strip may be caught at the crimping portion. However, since there is no means for cleaning the pressure roll inside the high vacuum chamber from the outside, the high vacuum is returned to the atmospheric pressure, and the efficiency of the high-speed laminating equipment is significantly impaired.

Further, when a joint weld between steel strips and a stitcher joint between aluminum strips passes through the pressure roll, an indentation is generated on the surface of the pressure roll, and the indentation of the pressure roll at the time of laminating thereafter causes a poor appearance of the laminate surface. cause.

Therefore, it is necessary to separate the crimping roll from the steel strip or the aluminum strip when the joining portion (welding portion) passes through the crimping roll, but when the crimping roll is in the high vacuum chamber,
If a moving mechanism for the pressure bonding roll is provided, a high vacuum cannot be maintained because a mechanical clearance is inevitable in the vacuum seal part.

[0024]

Means for Solving the Problems The present inventors have found the following method as a result of various studies on a method of high speed laminating a resin film on a steel strip or an aluminum plate. That is,

(1) When laminating a resin film on both sides or one side of a running steel strip or aluminum strip by thermocompression bonding, a pair of seal rolls sandwiching the steel strip or aluminum strip is arranged in front of the pair of pressure bonding rolls. A pair of intermediate rolls are arranged in close contact between the pressure roll and the seal roll, and a closed space surrounded by these three pairs of rolls and a seal plate on the side of the roll is depressurized. Laminating method.

(2) The laminating method described in (1), wherein the surface roughness of the steel strip or aluminum strip is 0.5 micron or less as an average roughness.

(3) The laminating method according to (1), wherein the degree of vacuum in the depressurized closed space is 50 Torr or less.

(4) The laminating method according to (2), characterized in that the degree of vacuum in the depressurized closed space is 50 Torr or less.

As the steel strip, a plated original plate, a tin-plated steel plate,
An aluminum plate for a can is used as a nickel-plated steel plate, a chrome-plated steel plate (tain-free steel), an aluminum-plated steel plate or an alloy-plated steel plate thereof, or an aluminum strip.

Polyester resins (polyethylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, etc.), acid-modified polyolefin resins (polyethylene, polypropylene, etc.), and polyamide resins (nylon, etc.) are used as the heat-bondable resin film.

The temperature of the steel strip or aluminum strip during thermocompression bonding is set to 5 ° C. lower than the melting point of the resin when the resin film to be laminated is a single layer.

When the resin film has two layers and the resin melting point on the non-adhesive side is higher than the resin melting point on the adhesive side, the temperature of the steel strip or aluminum strip is within the range of the resin melting point on the adhesive side plus or minus 5 ° C.

The upper limit of the temperature is the film fusion to the pressure roll, and the lower limit of the temperature is the limit of the thermal adhesive force. In the case of a single layer film, a resin having a strong heat adhesive property is appropriately selected.

The traveling speed of the steel strip or aluminum strip is 200
In the high-speed laminating of m / min or more, it is necessary to satisfy the following two conditions in order to prevent air entrapment.

First, regarding the surface roughness of steel strips and aluminum strips, if the average roughness exceeds 0.5 micron, the air staying in the recesses of the roughness becomes insufficiently diffused even in the decompression chamber, and the steel strips or Entrapped as bubbles between the aluminum strip and the resin film.

If the average roughness is less than 0.1 micron, scratches are likely to occur when the steel strip or aluminum strip is threaded, resulting in a decrease in commercial value.

Secondly, when the vacuum degree in the decompression chamber becomes a large value from 50 torr and the vacuum degree is lowered, even if the surface roughness is less than 0.5 micron in average roughness, the dwelling air in the roughness concave portion is diffused. Becomes insufficient and air entrapment occurs.

As the degree of vacuum is raised to a higher vacuum, the more advantageous the condition is to prevent air entrapment, but the pressure bonding roll is constructed so that it can be withdrawn so that it can be retracted when passing through the joint portion of the steel strip or aluminum strip. Therefore, sealing cannot be performed completely, so the limit is about 1 torr in actual operation.

As described above, the purpose of preventing air entrapment in high-speed laminating can be achieved, but the following consideration is required in actual operation.

That is, it is desirable that the volume of the decompression chamber is as small as possible, and as an example of obtaining the minimum volume, as shown in FIG. 1, a steel strip 6 or an aluminum strip 6 is sandwiched on the upstream side of the pressure roll 3. A pair of seal rolls 1 is provided, and an intermediate roll 2 for adjusting the rotation direction to these rolls
It is that they are in intimate contact with each other through the contact and are in close contact with the pressure-bonding roll 3. The reason why the capacity should be small is shown below.

When laminating by a thermocompression bonding method, the radiant heat from the preheated steel strip 6 or aluminum strip 6 raises the entire depressurization chamber 5 to near the melting point of the resin in continuous operation, so that a large-capacity depressurization chamber is filled with a resin film. The film is heated and partially melted during passage of No. 8, and in the case of a stretched film, shrinkage of the film occurs and satisfactory lamination cannot be performed.

In order to avoid these dangers, it is desirable to make the decompression chamber 5 as small as possible so as to minimize the film passage time.

Further, the foreign matter may be a pressure roll 3 or a seal roll 1.
If you bite into it, it is necessary to return it to atmospheric pressure and care for the roll, but in a decompression chamber with a small volume like this, the time to recover to a predetermined vacuum degree can be shortened, and the capability of high-speed laminating equipment can be reduced. Down can be minimized.

FIG. 1 shows a seal mechanism for the side surfaces of the seal roll 1, the intermediate roll 2 and the pressure roll 3.

In order to seal the depressurized space 5 surrounded by a total of 6 rolls from the roll side surface, the roll side surface has a flat mirror-finished surface except for the shaft portion 4, and the surface thereof is made of wear-resistant ceramic (such as chromium oxide). The seal plate 7 coated with is contacted.

The seal plate 7 is provided with a pipe 9 connected to a vacuum pump, and the depressurized space 5 is constantly sucked by the vacuum pump.

Since the seal plate 7 is gradually worn during continuous operation, it is periodically replaced. The exhaust capacity of the vacuum pump is appropriately selected so that the degree of vacuum in the decompression space 5 is within a predetermined range.

The present invention will be described below based on examples.

Table 1 shows the examples and comparative examples.

[0050]

[Table 1]

Examples 1, 2 and Comparative Examples 1, 2, 3 to 2
In order to perform high speed laminating at 00 m / min without air entrainment, the surface roughness of the steel strip 6 or aluminum strip 6 should be 0.5 μ or less in average roughness and the vacuum degree should be 50 Torr or less.

Further, it is understood that at a speed of 300 m / min or more, air entrapment can be prevented by further lowering the surface roughness or increasing the vacuum degree.

Table 1 shows polyethylene terephthalate (melting point 265 ° C.) at a pressure bonding temperature of 260 ° C., but polybutylene terephthalate (melting point 230 ° C.)
Nylon 6 (melting point 215 ° C), polypropylene (melting point 1
88 ° C.) was also laminated at the respective melting points minus 5 ° C., and the same results as in Table 1 were obtained.

Further, in Table 1, the material has a plate thickness of 0.2.
8. A tin-plated steel strip having a plate width of 500 mm was used, but the same results as in Table 1 were obtained even if a tin-free steel strip, a nickel-plated steel strip or an aluminum strip for cans was used.

[0055]

EFFECTS OF THE INVENTION The production of a can-making material by the resin laminating method can prevent environmental pollution due to a solvent in the present painting / baking process, and eliminate consumption of solvent volatilization energy.

In particular, the high-speed laminate according to the present invention can be mass-produced and can inexpensively and stably supply a can-making material, and at the same time tin plating or tin-free plating (chromium plating).
Since the line speed of the plating line and the laminating speed match, the laminating equipment can be installed in the plating line, and thus the manufacturing cost can be further reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a device of the present invention.

[Explanation of symbols]

 1 seal roll 2 intermediate roll 3 pressure bonding roll 4 roll shaft 5 decompression space (decompression chamber) 6 steel strip or aluminum strip 7 side seal plate 8 resin film 9 exhaust pipe provided on the side seal plate

Claims (4)

[Claims] 1. When laminating a resin film on both sides or one side of a running steel strip or aluminum strip by thermocompression bonding, a pair of sealing rolls sandwiching the steel strip or aluminum strip is arranged in front of the pair of pressure bonding rolls. Characterized in that a pair of intermediate rolls are arranged in close contact with each other between the pressure roll and the seal roll, and a closed space surrounded by these three pairs of rolls and a seal plate on the side surface of the roll is depressurized. Lamination method. 2. The laminating method according to claim 1, wherein the surface roughness of the steel strip or aluminum strip is 0.5 micron or less as an average roughness. 3. The laminating method according to claim 1, wherein the degree of vacuum in the depressurized closed space is 50 Torr or less. 4. The laminating method according to claim 2, wherein the vacuum degree of the decompressed closed space is set to 50 torr or less.