JP3682563B2 - Welding method for bottom material of tube container - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a bottom material welding method for a synthetic resin tube container.
[0002]
[Prior art]
As a method for forming a bottom surface of a synthetic resin tube container that can be erected by providing a flat bottom surface, a tube container body 1 having an open bottom surface is conventionally set upside down as shown in FIG. At the same time, the bottom material 2 made of synthetic resin is placed on the bottom open end 1a, and the bottom plate 2 is welded to the end surface of the bottom open end 1a by pressing the hot plate 3 from above. A method of cutting and removing unnecessary portions (outer portions of the cut lines 4) on the periphery of the material 2 can be considered.
[0003]
[Problems to be solved by the invention]
However, in the above prior art, there is a problem that the welding peripheral portion 5 is also cut and removed by cutting the peripheral portion of the bottom material 2, so that the welding area is reduced and sufficient welding strength cannot be obtained.
[0004]
In addition, the end surface of the bottom open end 1a may be slightly inclined with respect to the horizontal plane due to the bending deformation of the tube container main body 1 due to the pressing force of the hot plate 3 during welding or the illegal deformation from the beginning. There is a problem that the welding strength is weak at the bottom open end 1a portion.
[0005]
Further, in this type of tube container, the flat bottom surface often projects outwardly due to an increase in the internal pressure of the container due to an increase in the environmental temperature or external stress (for example, pressing of the trunk). There was a problem that the standing stability (sitting) deteriorated.
[0006]
Therefore, the present invention was devised to solve the above-described problems in the prior art, and obtains sufficient and reliable welding between the bottom open end of the tube container body and the bottom material, and high standing stability. Therefore, it is an object of the present invention to provide a tube container that exhibits a perfect sealing property and stably maintains a standing posture when placed at rest.
[0007]
[Means for Solving the Problems]
In order to solve the above technical problem, the means of the first invention of the present invention includes:
A step of bending the bottom open end of the synthetic resin tube container body with the bottom open inward to form a curled portion;
The tube container main body is mounted on a holding device having a guide hole having a shape corresponding to the peripheral shape of the bottom of the tube container main body, a cutter standing on the upper surface of the peripheral edge of the guide hole, and having a sleeve guide that is vertically controlled. In addition to being set upside down, a synthetic resin film-like bottom material is placed on the cutter, and while lowering the sleeve guide, the hot plate is lowered from above the sleeve guide to remove the bottom material from the tube container body. After crimping and welding to the open end of the bottom, and then moving the hot plate, the cutter backing plate is lowered and pressed against the bottom material, the bottom material is cooled, and the outside of the welded portion is cut by the cutter. Process,
Forming a depressed recess in the bottom material;
Consists of.
[0008]
The means of the second invention of the present invention is:
A step of bending the bottom open end of the synthetic resin tube container body with the bottom open inward to form a curled portion;
The tube container main body is mounted on a holding device having a guide hole having a shape corresponding to the peripheral shape of the bottom of the tube container main body, a cutter standing on the upper surface of the peripheral edge of the guide hole, and having a sleeve guide that is vertically controlled. Place the synthetic resin bottom material in which the concave portion is molded in advance on the cutter and place the bottom material in the tube container by lowering the hot plate from above the sleeve guide while lowering the sleeve guide. After crimping and welding to the bottom open end of the main body, and then moving the hot plate, lower the cutter support plate to press against the bottom material, cool this bottom material, and cut the outside of the welded part with the cutter And a process of
Consists of.
[0009]
A pressing jig corresponding to the bottom circumferential shape of the tube container main body and having a concave portion having a pressing surface that is inclined downward and expanding downward is disposed above the sleeve guide, and the tube container main body is attached to the holding device. After setting in an inverted state, the heated pressing jig is lowered, and the outer edge of the bottom open end of the tube container body is pressed by the pressing surface of the pressing jig to form the curled portion.
[0010]
Moreover, after blowing hot air from above on the film-like bottom material welded to the bottom open end of the tube container body, the cooling pressing jig provided with a convex portion of the desired shape is lowered and pressed, It is preferable to form a recess in the bottom material.
[0011]
[Action]
Since the curled portion is formed in advance at the bottom open end of the tube container main body, the welding area with the bottom material is widened, thereby achieving strong and reliable welding over the entire circumference.
[0012]
In addition, since the depressed portion is formed in the bottom material, the bottom surface of the tube container does not protrude outwardly and is improved in the standing stability.
[0013]
In the invention of claim 3, the molding of the curled portion and the welding of the bottom material can be easily and efficiently carried out in a series of steps using the same holding device.
[0014]
In the invention of claim 4, the welding of the bottom material and the forming of the recess can be easily and efficiently performed in a series of steps using the same holding device. When the material is bent and deformed, the outer edge of the material is crimped to the upper surface of the curled part while being displaced inward, so the unwelded part slightly remaining on the lower surface of the outer edge of the bottom material is completely welded to the curled part. This sufficiently enhances the tightly welded assembly between the tube container body and the bottom material, and improves the appearance of the bottom of the molded tube.
[0015]
【Example】
FIG. 1 shows an embodiment of a step of curling the bottom open end 1a of the tube container body 1 inward prior to the welding of the bottom material 2. FIG.
[0016]
The holding device 10 is provided with a tube holder 12 provided with a vent hole 13 on a table 11 and a plurality of cylinders 14 for controlling the vertical movement of a rod 15. A guide hole 17 having a shape corresponding to the peripheral shape of the bottom of the container body 1 is provided, a sleeve guide 16 having a cutter 18 is fixed to the upper surface of the peripheral edge of the guide hole 17, and the rod 15 is biased upward by a spring 19. In the sleeve guide 16, a water cooling channel 16a is opened.
[0017]
Above the sleeve guide 16, a heated pressing jig 20 having a concave surface 21 having a pressing surface 22 corresponding to the bottom circumferential shape of the tube container main body 1 and being inclined downward is moved up and down. Arranged to be possible.
[0018]
The pressing jig 20 is provided with a vent hole 23 that functions as an air vent communicating with the upper end of the recess 21, and the lower end portion around the recess 21 is formed of a heat insulating material 24. The angle α with respect to the vertical of the surface 22 is preferably about 60 ° from many trial results.
[0019]
Therefore, when the tube container body 1 is set upside down on the holding device 10 and the heated pressing jig 20 is lowered while the vent holes 13 and 23 functioning as air vents are opened, the heat insulating material 24 becomes the sleeve guide 16. Since the pressing surface 22 presses the outer edge of the bottom opening end 1a of the tube container body 1, the bottom opening end 1a heated and softened by the pressing jig 20 is bent inward. Is formed on the curled portion 1b (see FIG. 1B).
[0020]
The formation of the curled portion 1b can increase the welding area with respect to the bottom material 2, but the curl forming method is not limited to the present embodiment. For example, the bottom open end of the tube container body 1 is used. Implemented by a method using a pressing jig that presses 1a in the horizontal direction while heating 1a, or a method using a molding jig in which the upper end of the inner peripheral surface has been curled inwardly in advance. May be.
[0021]
FIG. 2 shows an embodiment of a process of welding the bottom material 2 to the curled portion 1b formed at the bottom open end 1a of the tube container body 1. In this process, instead of the pressing jig 20, A hot plate 25 (FIG. 2A) and a cutter receiving plate 26 with a water cooling device (FIG. 2B) are used.
[0022]
First, as shown in FIG. 2A, the sleeve guide 16 is raised to the original position, the sheet film 30 as the bottom material 2 is placed on the cutter 18, and the tube container body 1 is left with the vent hole 13 being opened. In contrast, the sleeve guide 16 is lowered to a predetermined position, the hot plate 25 heated to about 210 to 220 ° C. is lowered, and the sheet film 30 is pressure-bonded to the upper surface of the curled portion 1b on the lower surface for about 2 seconds.
[0023]
Next, after retracting the hot plate 25, the cutter receiving plate 26 is lowered and pressed against the sheet film 30 as shown in FIG. 2B, the sheet film 30 is cooled, and the outside of the welded portion is cut by the cutter 18. To finish the sealing operation.
[0024]
As the material of the tube container body 1, all thermoplastic synthetic resins that can be welded by a hot plate, or this thermoplastic synthetic resin is used as a sealing layer, and an ethylene vinyl alcohol copolymer (EVOH) is used as necessary to protect the contents. Or a laminate of aluminum laminate films is preferred.
[0025]
Further, as the bottom material 2, a sheet film 30 such as a single layer sheet film of the above-mentioned thermoplastic synthetic resin, a laminated film laminated with a reinforcing material (polypropylene, polycarbonate, polystyrene, polyethylene terephthalate, etc.) that resists changes in internal and external pressure of the container. Alternatively, the thermoplastic synthetic resin sheet or a laminated sheet in which an EVOH layer is provided on the sheet, and a thermoforming molded article that is previously molded to have the recesses 2a are suitable.
[0026]
FIG. 4 shows an example of the bottom material sheet film 30. The outer layer 31 is a heat-resistant lacquer coating, the intermediate layer 32 as a deformation prevention reinforcing layer is polypropylene, high-density polyethylene, the intermediate layer 33 is EVOH, and the inner layer 34 is It is composed of low density or very low density polyethylene.
[0027]
FIG. 3 shows an example of a step of forming a recess 2a that is difficult to reversely project outward and deformed on the bottom material sheet film 30 welded to the tube container main body 1. That is, first, FIG. The hot air is sprayed from the upper nozzle 27 to the center portion of the sheet film 30 as shown in FIG.
[0028]
Next, as shown in FIG. 3B, the cooling pressing jig 28 having the convex portion 29 having a desired shape formed on the lower surface is lowered, and the convex portion 29 is pressed against the sheet film 30 to form the concave portion 2a. And let it cool and cure.
[0029]
At the time of forming the recess 2a, the sheet film 30 is curved and deformed, so that the outer edge portion is crimped to the upper surface of the curled portion 1b while being displaced inward, so that it slightly remains on the lower surface of the outer edge portion of the sheet film 30. The unwelded portion 30a (see FIG. 4) is also completely welded to the curled portion 1b.
[0030]
FIGS. 5 to 7 show variations in the shape of the recess 2a. In the bottom member 2 shown in FIG. 5, a reinforcing portion 35 made of the reinforcing material is formed in the diameter direction.
[0031]
8A to 8F show variations in the shape of the bottom circumference of the tube container formed by the guide hole 17 of the sleeve guide 16.
[0032]
【The invention's effect】
According to the present invention, since the curled portion is formed in advance at the bottom open end of the tube container main body, the welding area with the bottom material is widened, thereby achieving strong and reliable welding over the entire circumference. And complete sealability can be obtained.
[0033]
In addition, since the depressed portion is formed in the bottom material, the bottom surface of the tube container is not protruded and deformed outward, and the standing stability of the tube container and the stability in conveying the filling line are improved.
[0034]
According to the invention of claim 3, the molding of the curled portion and the welding of the bottom material can be easily and efficiently performed in a series of steps using the same holding device.
[0035]
According to the invention of claim 4, the welding of the bottom material and the forming of the concave portion can be easily and efficiently performed in a series of steps using the same holding device. When the material is bent and deformed, the outer edge of the material is crimped to the upper surface of the curled part while being displaced inward, so the unwelded part slightly remaining on the lower surface of the outer edge of the bottom material is also completely welded to the curled part. As a result, the welding strength can be further increased.
[Brief description of the drawings]
FIG. 1 is a state explanatory view showing an embodiment of a curl forming process in the present invention.
FIG. 2 is a state explanatory view showing one embodiment of a bottom material welding step in the present invention.
FIG. 3 is a state explanatory view showing one embodiment of a step of forming a recess in a bottom material according to the present invention.
FIG. 4 is an enlarged cross-sectional view showing an example of the configuration of a bottom material used in the present invention.
5A and 5B show examples of a recess formed in a bottom material according to the present invention, in which FIG. 5A is a cross-sectional view, and FIG. 5B is a bottom view.
6A and 6B show examples of recesses formed in the bottom material according to the present invention, in which FIG. 6A is a cross-sectional view, and FIG. 6B is a bottom view.
7A and 7B show examples of a recess formed in a bottom material according to the present invention, in which FIG. 7A is a cross-sectional view, and FIG. 7B is a bottom view.
FIG. 8 is a bottom view showing an example of the peripheral shape of the bottom of the tube container of the present invention.
FIG. 9 is a cross-sectional view showing a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1; Tube container main body 1a; Bottom part open end 1b; Curl part 2; Bottom material 2a; Concave part 3; Hot plate 4; Cut wire 5; Welding peripheral part 10; Cylinder 15; Rod 16; Sleeve guide 16a; Water cooling channel 17; Guide hole 18; Cutter 19; Spring 20; Press jig 21; Recess 22; Press surface 23; Ventilation hole 24; Cutter receiving plate 27; Nozzle 28; Cooling pressing jig 29; Convex part 30; Sheet film 30a; Unwelded part 31; Outer layer 32; Intermediate layer 33; Intermediate layer 34; Inner layer 35;

Claims (4)

The step of forming the curled portion (1b) by curving the bottom open end (1a) of the synthetic resin tube container body (1) with the bottom open inward, and the bottom circumferential shape of the tube container body (1) A holding device (10) having a guide hole (17) with a corresponding shape, a cutter (18) standing on the upper surface of the peripheral edge of the guide hole (17), and a sleeve guide (16) whose vertical movement is controlled. ), The tube container body (1) is set upside down, and a synthetic resin film bottom (2) is placed on the cutter (18), and the sleeve guide (16) is lowered. The bottom plate (2) is pressed against the bottom open end (1a) of the tube container body (1) and welded by lowering the hot plate (25) from above the sleeve guide (16). After moving the hot plate (25), the cutter receiving plate (26) is lowered and pressed against the bottom material (2) to cool the bottom material (2) and A method for welding a bottom material of a tube container, comprising: a step of cutting an outer side of a welded portion by a cutter (18); and a step of forming a depressed recess (2a) in the bottom material (2). The step of forming the curled portion (1b) by curving the bottom open end (1a) of the synthetic resin tube container body (1) with the bottom open inward, and the bottom circumferential shape of the tube container body (1) A holding device (10) having a guide hole (17) with a corresponding shape, a cutter (18) standing on the upper surface of the peripheral edge of the guide hole (17), and a sleeve guide (16) whose vertical movement is controlled. ), The tube container body (1) is set upside down, and a synthetic resin bottom material (2) in which a recess (2a) is previously formed is placed on the cutter (18), and the sleeve guide While lowering (16), the hot plate (25) is lowered from above the sleeve guide (16) to crimp the bottom material (2) to the bottom open end (1a) of the tube container body (1). After welding, and then moving the hot plate (25), the cutter support plate (26) is lowered and pressed against the bottom material (2) to cool the bottom material (2) Bottom material welding method of the tube container made of a step of cutting the outer welding portion by said cutter (18). A pressing jig (20) corresponding to the bottom circumferential shape of the tube container body (1) and provided with a concave portion (21) having a pressing surface (22) inclined downward and expanding downward is provided on the lower surface of the sleeve guide ( 16), the tube container body (1) is set upside down on the holding device (10), and then the heated pressing jig (20) is lowered, and the tube is pressed by the pressing surface (22). The method for welding a bottom material of a tube container according to claim 1 or 2, wherein the curled portion (1b) is formed by pressing the outer edge of the bottom open end (1a) of the container body (1). After the hot air is blown from above onto the film-like bottom material (2) welded to the bottom open end (1a) of the tube container body (1), a cooling press with a convex part (29) of the desired shape provided on the lower surface The bottom material welding method for a tube container according to claim 1, wherein the jig (28) is lowered and pressed to form a recess (2a) in the bottom material (2).

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