JPH0143616B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for manufacturing a tube container body, and more particularly, to a seamless tube container body in which the surface of a multilayer tube container body including a metal layer is coated with a continuous coating layer. A manufacturing method and an apparatus for manufacturing the same.

Conventionally, tube containers formed of only a synthetic resin layer have a soft and beautiful surface, but have a problem in that their barrier properties are significantly lower than those of metal tube containers. In order to insert metal into the wall of the main body of the tube container, the molding conditions for metal and synthetic resin are significantly different, so generally 3~
Create a metal layer adjusted to 100μ in advance,
A laminated sheet containing this metal layer is created, this laminated sheet is rolled into a cylindrical shape, and the ends of the laminated sheet are sealed together to form a cylindrical body. It came as a tube container with a mouth.

However, these tube containers with a metal layer generally have low pressure resistance, and the sealing part of the tube container body is easily damaged.
There was a problem that the contents leaked from the back seal during extrusion.

Also, since the back seals of the tube body are overlapped, a step is created, and in order to eliminate this step, it is necessary to apply excessive pressure to the overlapped portion during sealing. , there are problems such as cracks in the metal layer.
Also, if sufficient pressure is not applied when sealing the bottom, the area near the overlapping part of the back seal will not be completely sealed, and at that time, excessive pressure is likely to be applied, causing cracks in the metal layer. There is. In addition, since there is a large step on the back of the tube container, it is difficult to perform secondary processing such as surface printing and foil stamping.
If the pattern or the like were to cover the difference in level, there would be problems such as the pattern or the like being cut off, resulting in a lack of luxury and a decrease in product value.

To solve the above problem, we created a thin laminated film containing a metal layer, rolled it up and sealed the ends to create a cylindrical film.
The tube container, which has a main body made of a cylindrical film coated with a synthetic resin, has a smooth surface and can provide good strength and effectiveness without applying excessive pressure when sealing the bottom, printing, foil stamping, etc. has also been developed.

As a method for manufacturing such a tube container body, it is possible to directly apply the technology of coating the outside of a metal tube with resin or the technology of covering electric wires as disclosed in Japanese Patent Publication No. 38-332. These molding methods cover resin by adhering within the die, and are effective for thick coating molding of rigid materials that are difficult to deform under external pressure, such as metal pipes and electric wires.
In the case of a soft tube container body, which requires flexibility as in the present invention, it deforms and the coating layer becomes noticeably different depending on the location. It is difficult to obtain a uniform coating layer that suppresses the thickness variation to less than %.

In addition, the laminated film containing the metal layer is rolled up and the ends are sealed together in a continuous manner with a diameter of 10~
In order to seal a small diameter such as 50 mm, the coating resin is a thermoplastic resin, so it is necessary to apply pressure after heating and cooling it, and in the case of continuous sealing, it is difficult to obtain the strength and sealing When using the high frequency sealing method or ultrasonic sealing method, the heating is done from one side, and because the film is moving, it cannot be heated uniformly at all times, which tends to cause pinholes and unevenness, and only the outer surface is heated. Rather, providing a coating layer also on the inner surface improves protection performance and pressure resistance, so it is preferable to coat the inner surface in accordance with the outer coating layer.

To coat the inner surface, heat the thing to be coated,
A method of uniformly spraying powdered resin is used for steel pipes, etc., but this is impossible with a film like the one of the present invention, and the generally considered method is to use melted parison for internal coating. This seems to be a method of pressurizing the inside to fuse it to the inner surface of the cylindrical film. However, in this method, the molten parison will not be fused to the cylindrical film unless the ends of the cylindrical film coated with the inner surface are closed in some way. Therefore, if a cylindrical film with an inner surface coated with a metal layer is crimped to prevent air leakage, there is a problem that the metal layer will have cracks or wrinkles, resulting in a significant deterioration in quality. The problem with this method of attaching a valve is that it is difficult to start molding because the diameter is small.

Therefore, the present inventor invented a method for manufacturing a multilayer tube container body including a metal layer as described below. That is, a film is prepared in advance in which an adhesive resin layer, a metal layer, and an adhesive resin layer are laminated in this order, and this laminated film is rolled up while being wrapped around a winding guide, and the ends of the film are overlapped and fused to form a tube. In a method for manufacturing a tube container body in which a cylindrical film is prepared and the inner surface of the cylindrical film is coated with a synthetic resin, the pressure inside the molten parison for inner surface coating and the inner surface of the inner surface coated cylindrical film is maintained at approximately atmospheric pressure. , and by maintaining the air pressure between the molten parison for inner surface coating and the cylindrical film, and the outside of the uncoated cylindrical film and the inner surface coated cylindrical film at a pressure 0.1 to 30 cmHg lower than that on the inside,
This method of manufacturing a tube container body is characterized in that the inner surface of a cylindrical film is coated with a molten parison for inner surface coating. The manufacturing apparatus according to the present invention will be explained below with reference to the drawings. 1 and 2 show an apparatus for manufacturing a tube container body according to the present invention, in which a film 1 is prepared in advance by laminating an adhesive resin layer, a metal layer, and an adhesive resin layer in this order, and this laminated film 1 is wound. The ends of the laminated film 1 are fused together using a sealing machine ( ) to form a cylindrical film 3, and the tip of this cylindrical film 3 is pulled off (towards the left in the drawing). ), a continuous cylindrical film 3 is produced. Also, the tip of the die head 4 for inner coating is the winding guide 2'.
Insert the inner surface coating die head 4 connected to the extruder 26 into the winding guide 2' so that the tip comes out,
As shown in FIG. 3, a heat insulating layer 6 having air holes 5 is provided between the winding guide 2' and the inner coating die head 4, and is fixed in place so as to uniformly contact the outer surface of the cylindrical film 3. A first cooling jacket 9 is attached to the cylindrical film 3 for cooling the inner surface coated cylindrical film 8 from the outer surface, the inner surface of which is coated with the molten parison 7 extruded from the tip of the die head 4 for inner surface coating.
The inner surface coated cylindrical film 8 is placed in contact with the inner surface coated film 8 immediately after the inner surface is coated.
The outer surface of the inner-coated cylindrical film 8 is covered with the molten parison 11 which is inserted into the hole of the outer-coating die head 10 connected to the outer-coating die head 10 and extruded from the outer-coating die head 10. A cooling chamber 13 that cools the coated cylindrical film 12 from the outside; and a suction chamber that lowers the air pressure outside the inner and outer coated cylindrical film 12 by uniformly having holes 28 communicating with the outer surface of the inner and outer coated cylindrical film 12. 14
An arm is provided at the tip of the second cooling jacket 15 having an arm so that the second cooling jacket 15 comes into contact with the inner and outer coated cylindrical film 12 immediately after the outer surface of the inner and outer coated cylindrical film 8 is coated with the molten parison 11. The inner surface coating die head 4, the first cooling jacket 9, and the first suction cover 1 are provided as follows.
6. The first suction space 17 surrounded by the inner surface coating melting parison 7 is made lower than the outside pressure, and the first cooling jacket 9, the outer surface coating die head 10, the outer surface coating melting parison 11, and the inner surface coating cylindrical film are removed. 8. A second suction space 19 surrounded by a second suction cover 18, a die head 10 for outer surface coating, a second cooling jacket 15, a melting parison 11 for outer surface coating, a cylindrical film 12 with inner and outer surfaces coated, and a third suction cover. 2
The pressure inside the internally coated cylindrical film 8 is maintained at approximately the same pressure as the outside pressure, while maintaining the same pressure as the third suction space 21 surrounded by 0, and lower than the outside pressure. The present invention relates to a method and apparatus for manufacturing a tube container body whose inner and outer surfaces are coated with a continuous metal layer. The inner and outer surface-coated cylindrical film 12 thus obtained is cut to a desired length to form a tube container body, and a mouth portion is formed at one end of the tube container body to manufacture the tube container.

The adhesive resin layer of the laminated film 1 may be a combination of an adhesive such as polyvinyl acetate resin and a resin such as polyethylene, or an unsaturated resin such as ethylene methyl acrylate (EMA) or ethylene-acrylic acid copolymer resin (EAA). Polyolefin resin modified with carboxylic acid or its derivatives is used to bond metal layers, roll up a laminated film and fuse the edges together, and fuse with a coating layer, whether it is a single layer or a multilayer film. Alternatively, the inner layer and multilayer may be made of different resins. In addition, the metal layer has high extensibility such as aluminum, has few pinholes,
A metal foil with a thickness of 5 to 60 μm, preferably 7 to 20 μm is good.

Here, the film 1, which has the metal layer laminated on both sides with an adhesive resin layer, is placed on the guides 2, 2'.
The cylindrical film 3 is created by wrapping and rolling the laminated film 1 together and fusing the ends of the laminated film 1. This winding can be done either in a cylindrical shape or in a helical shape; It is preferable to wrap it in a cylindrical shape because it is easier to use a device for fusing the ends together, and when printing, foil stamping, etc., a good product can be obtained with less variation in wall thickness in the length direction.
As described above, the laminated film 1 is rolled up using the winding guides 2 and 2', and fused to form a cylindrical shape.
By pulling off the tip, a continuous cylindrical film 3 can be obtained. In addition, laminated film 1
It is well known that this can be produced by extrusion lamination using a T-die method or by using a dry lamination laminator.

In order to coat the outer surface of the continuous cylindrical film 3 obtained in the above manner with resin, the cylindrical film 3 is
Because it is thin and has no waist of about 50 to 200 μ,
The cylindrical film 3 must be coated and cooled while keeping it in a desired shape, and as described above, the method for holding the cylindrical film 3 in the present invention is to cover almost all of the inside of the cylindrical film 8 whose inner surface is coated. Hold at ambient pressure. That is, the cylindrical film 12 whose inner and outer surfaces are coated is taken off by a take-off machine (not shown), and then cut into a desired length.
No need to close. Therefore, molding can be performed with almost no fluctuations caused by a pulling machine, a cutting machine, etc.

The core 22 of the die head 3 for coating the inner surface also has an air hole 23, and the air pressure inside the inner surface coated cylindrical film 8 can be adjusted by this.

By keeping the inside of the internally coated cylindrical film 8 at around 1 atm and keeping the outside below 1 atm, a pressure difference is created between the inside and outside of the internally coated cylindrical film 8. Therefore, the internally coated cylindrical film 8 expands into a desired shape. At this time, the third
As shown in the figure, by providing air holes 5 in the heat insulating layer between the inner surface coating die head 4 and the winding guide 2', the air pressure outside the inner surface coating melting parison 7 is made to match that of the entire first suction space 17. Since the pressure inside the inner surface coating molten parison 4 is set to be higher than the outside, the inner surface coating molten parison 7 can swell and contact and fuse with the inner surface of the cylindrical film 3. By using the above-mentioned inner surface coating method, even a cylindrical film having a small diameter can be easily coated on the inner surface. Here, immediately after coating the inner surface of the cylindrical film, it is necessary to cool it rapidly. In the present invention, the first cooling jacket 9, which is constantly cooled by a cooling medium such as water or oil, is brought into contact with the cylindrical film 3 from the outside immediately after the inner surface is coated. That is, when cooling from the inside, the tip of the die head 4 for coating the inner surface becomes complicated, and only a thick tube container can be formed.
Furthermore, cooling from the outside makes it more difficult for the sealed portion of the cylindrical film 3 to be reheated, resulting in a film with a stable diameter.

Next, after the inner surface is coated, the inner surface coated cylindrical film 8 is transferred to the outer surface coating die head 1 while maintaining a distance so as not to contact the outer surface coating die head 10.
0 into the hole 24. Here, while the inner surface coated cylindrical film 8 passes through the outer surface coating die head 10, it receives radiant heat from the die head, the surface is heated, and the fusion with the outer surface coating molten parison 11 is strengthened, but the entire film is heated. If the temperature is too high, the seal part of the cylindrical film 3 will stretch and separate, so make sure to adjust the temperature inside the die head to match the molding speed (for example,
It is preferable to control the temperature of the internally coated cylindrical film by providing an air hole in the core of the die head for externally coating to ventilate the internal air or shorten the length of the second suction chamber.

The outer surface coating molten parison 11 extruded from the outer surface coating die head 10 covers the outer surface of the inner surface coated cylindrical film 8 outside the die. Although in-die bonding has high fusion strength, it shrinks greatly and wrinkles easily, and the internally coated cylindrical film 8 receives high heat, making the dimensions unstable and causing variations in wall thickness. Since there are problems such as a large amount of easily appearing, adhesion outside the die is performed. At this time, the air pressure in the second suction space 19 and the third suction space 21, which are partitioned by the outer surface coated melting parison 11, is lower than the pressure inside the inner surface coated cylindrical film 8, as in the first suction space 17. 2 suction space 19 and 3rd suction space 19
The atmospheric pressure in the suction space 21 is maintained at approximately the same atmospheric pressure. In other words, if the air pressures in the second suction space 19 and the third suction space 21 are different, the molten parison 11 for outer surface coating becomes unstable and moves back and forth, without contacting the outer surface of the inner coated cylindrical film 8. This is because good molding cannot be achieved because the mold spreads to the suction port. Therefore, the second suction space 19 and the third suction space 21
It is desirable to maintain a constant pressure using the same suction machine for the tubes that suction the water.

The cylindrical film 12 whose outer surface has been coated in the manner described above is cooled by the second cooling jacket 15. The suction of the second cooling jacket 15 on the take-up machine side is to maintain its shape.

The air pressure in the first to third suction spaces 17, 19, 21 and the suction chamber 14 of the second cooling jacket 15 is 0.1 to 30 cmHg, preferably 0.5 to 30 cmHg, compared to the air pressure inside the internally coated cylindrical film 8, which is approximately 1 atm.
The pressure should be 20cmHg lower, and the pressure change should be as small as possible, preferably within 0.1cmHg. That is, if the pressure difference is less than 0.1 cmHg, it will be unstable and the melted parison 7 for inner surface coating and the coated cylindrical film 8 will not expand sufficiently. Also, the pressure difference is 30cm
If it exceeds Hg, it will swell too much, causing problems such as damage to the sealing part or the diameter becoming larger than desired, so set it to 0.1 to 30 cmHg. For suction, it is best to use a water pump that can adjust the pressure at a low level, and it is also possible to add a preliminary chamber between the pump and each suction space or chamber to further stabilize the suction.

The resin for the inner and outer coating layers used in the present invention is desirably a polyolefin or modified polyolefin having a melt index of 2.5 or less, preferably 2.0 to 0.3. In other words, resins with a melt index of 2.5 or higher not only have lower pressure resistance and are more prone to stress cracks, but also have poor moldability and surface properties, so polyolefins or modified polyolefins with a melt index of 2.5 or lower are used. is good. Further, the coating layer may be not only a single layer but also a multilayer. For example, the die head for outer surface coating may be a multilayer die head 25 as shown in FIG.
Separate resins are sent from two extruders 24, 24' to a die head and multilayered in a multilayer die head 25.
It is also possible to extrude and coat the multilayer outer surface coating molten parison 11 from the tip of the die head. for example,
A combination of a transparent resin and a colored resin, a combination of a polyamide resin and a maleic anhydride-modified polyolefin resin, etc. can be considered, and the die head for inner coating can also be made into a multilayer die head, and the inner coating layer can also be multilayered.

As described above, the manufacturing method and manufacturing apparatus of the present invention can easily provide a thin coating layer on the inner and outer surfaces of a thin and flexible multilayer film containing a metal layer. In particular, in order to manufacture tubes with a small diameter such as tube container bodies, if you try to insert a mandrel etc. inside the cylindrical film, it becomes complicated and it is practically difficult from the viewpoint of the strength of the parts and the manufacturing of the parts. This is particularly effective in that it is a manufacturing method that does not involve inserting a mandrel inside the tube to easily manufacture a tube with a small diameter. Continuous seals also have problems with strength, appearance, pinholes, etc.
In the present invention, since the inner and outer surfaces can be coated with a flexible and high-strength resin, the defects of the conventional cylindrical film containing a metal layer can be compensated for.
For example, if the coating layer is multilayered as described above, and one of the layers is made of a barrier resin such as polyamide resin, saponified ethylene-vinyl acetate copolymer, or polyvinylidene chloride, a tube container with higher protection performance can be obtained. . Here, the outer and inner surfaces of the tube container body obtained by the present invention are of course seamless and almost smooth, and only the cylindrical film with a seal of about 5 to 30% of the total wall thickness has a seal. Can be manufactured without any difference in wall thickness. Therefore,
When welding the mouth and sealing the bottom, there is no need to apply excessive pressure for welding, and no cracks occur. Furthermore, even when printing, foil stamping, varnish coating, etc. are performed on the surface of the tube container body, secondary processing can be performed sufficiently without applying excessive pressure as with general plastic tube containers. In particular, as described above, in the manufacturing method of the present invention, after coating the inner and outer surfaces of the cylindrical film, there is no need to seal the inner and outer covering cylindrical films to maintain internal air pressure, and molding can be performed in an open state. It is easy to mold, wrinkles and the like are less likely to occur, and pressure unevenness caused by cutting machines can be kept to a minimum, resulting in stable molding and other great effects.

Note that the object of the present invention can also be achieved by using the first and second jackets 9, 15 together in the manufacturing method of the present invention to cover the inner and outer surfaces almost simultaneously as shown in FIG. Of course.
That is, the specific device shown in FIG. 5 has a heat insulating layer 6 and a winding guide 2' on the outer surface, each having an air hole 5' communicating with the front and back, and an inner surface having an air hole 23' in the core 22 communicating with the outside air. It has an outer surface coating die head 10' having a hole in the center and spaced apart from the coating die head 4' so as not to contact the cylindrical film 3.
Immediately after the parisons 7' and 11' extruded from the two die heads 4' and 10' are coated on the cylindrical film 3 almost simultaneously, a cooling jacket 15' having a cooling chamber 13' and a suction chamber 14' is opened from the outside. A suction cover 16 is provided between the cooling jacket 15' and the inner surface coating die head 4' to cool the inner surface coating molten parison 7'.
A suction machine is connected to suck the air inside the suction cover 16' so that the air pressure inside and outside of the melted parison 11' for coating the inner surface is lower than that inside the melted parison 7' for coating the inner surface. Molding is possible using a tube container body manufacturing apparatus characterized by the following. In this method, although it is necessary to particularly increase the cooling power of the cooling jacket 15', the overall length is shortened and the thermal history is also reduced. If each coating layer is viewed independently, it is the same as the sequential coating method described above.

In the present invention, more stable molding can be achieved if a cooling step is further performed after cooling the inner and outer surfaces for sufficient cooling.

[Brief explanation of drawings]

The drawings are explanatory diagrams relating to the manufacturing method of the present invention, in which FIG. 1 is a simplified diagram showing one embodiment of the manufacturing apparatus of the present invention, and FIG. 2 is a partially enlarged simplified diagram of FIG. 1. , FIG. 3 is a sectional view taken along line I-I' in FIG. 1, FIG. 4 is a simplified diagram of an apparatus using a multilayer die head, and FIG. 5 is a simplified diagram of an apparatus for simultaneously coating the inner and outer surfaces. be. 1... Laminated film, 2, 2'... Winding guide, 3... Cylindrical film, 4... Die head for inner coating, 5... Air hole, 6... Heat insulating layer, 7... Melting for inner coating Parison, 8... Inner surface coated cylindrical film, 9... First cooling jacket, 10... Outer surface coating die head, 11... Outer surface coating parison, 12... Inner and outer surface coated cylindrical film, 13...
...Cooling chamber, 14...Suction chamber, 15...Second cooling jacket, 16...First suction cover, 17...First suction space, 18...Second suction cover, 19...
Second suction space, 20...Third suction cover, 21...
...Third suction space.

Claims (1)

[Claims] 1. A film is prepared in advance by laminating at least an adhesive resin layer, a metal layer, and an adhesive resin layer in this order, and the ends of the laminated film are overlapped and fused to create a cylindrical film. In this method for manufacturing a tube container body in which the inner and outer surfaces of a cylindrical film are coated with synthetic resin, the pressure inside the molten parison for inner coating and the inner surface of the inner coated cylindrical film is maintained at approximately atmospheric pressure, and The air pressure between the melted parison for inner surface coating and the cylindrical film, and the outside of the uncoated cylindrical film and the inner surface coated cylindrical film is 0.1 compared to the inside.
The molten parison for inner surface coating is coated on the inner surface of the cylindrical film by maintaining the atmospheric pressure to be ~30cmHg low, and the molten parison for outer surface coating is further coated on the outer surface of the cylindrical film already coated on the inner surface outside the die. A method of manufacturing a tube container body. 2. The method for manufacturing a tube container main body according to claim 1, characterized in that immediately after the inner surface of the cylindrical film is coated with the molten parison for inner surface coating, the inner surface coated cylindrical film is cooled from the outer surface. 3. Prepare a film in advance in which the adhesive resin layer, metal layer, and adhesive resin layer are laminated in this order, roll this laminated film around a winding guide, and fuse the ends to form a continuous cylinder. In an apparatus for producing a tube container main body, the outer and inner surfaces of the tubular film are coated with a synthetic resin. A die head for inner surface coating comprising a heat insulating layer having a communicating air hole and the winding guide, a cooling jacket that contacts the inner surface of the cylindrical film immediately after the parison for inner surface coating is coated on the inner surface of the cylindrical film, and a die head for inner surface coating. a die head for outer surface coating having a hole in the center with a gap maintained so as not to contact the cylindrical film; a cooling jacket that contacts the outer surface of the cylindrical film immediately after the outer surface of the cylindrical film is coated with a parison for outer surface coating; and at least the cooling jacket and the inner surface. A manufacturing apparatus for a tube container main body, characterized in that a suction cover is provided between the coating die head and between the cooling jacket and the outer surface coating die head to form a suction space, and the suction space is connected to a suction machine. .