JP3552220B2 - Manufacturing method of composite container - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method for manufacturing a composite container comprising an inner container made of plastic and an outer container made of paper.
[0002]
[Prior art]
As containers for selling drinking water, polyethylene terephthalate (hereinafter also referred to as PET) containers, so-called PET bottles, are widely used.
Since PET bottles are lighter than glass containers, they are easier to transport and store, and are advantageous in terms of manufacturing costs.
However, if it is discarded or buried in the soil, it will not be dissolved in water, will not oxidize, and will not be decomposed by microorganisms, so it will maintain its form for a long time.
Moreover, PET bottles are consumed in extremely large amounts. This is true not only for PET bottles but also for plastic containers in general, and the resulting environmental pollution is a serious problem.
[Problems to be solved by the invention]
One way to alleviate this problem is to use as little plastic as possible in the container.
However, if the amount of plastic used is simply reduced, the mechanical strength of the plastic container decreases, and the plastic container does not function as a container.
Therefore, a composite container combining paper has attracted attention.
This composite container is formed by covering the plastic inner container with a paper outer container, and the strength of the inner container is compensated by the strength of the paper outer container to reduce the amount of plastic used. .
Needless to say, paper is easily broken down by water and reduced to plant fiber, and is degraded by microorganisms.
Therefore, the composite container using paper is effective in alleviating the problem of environmental pollution.
SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a composite container which can manufacture a composite container having such advantages at low cost.
[0004]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a method for producing a composite container comprising a plastic inner container and a paper outer container , wherein the outer container is formed into a bottom mold for molding a bottom of the composite container. A bottom into which the bottom of the outer container is inserted, the bottom of the outer container is inserted into the recess, and the outer container is attached to the bottom mold, and then the heated preform serving as the inner container is placed inside the outer container. And then, a split mold for molding a part other than the bottom portion of the composite container is united with the bottom mold, and then, a stretching rod is inserted into the preform to stretch the preform, and the preform is stretched. The fluid is pressurized and injected into the inside.
Further, the present invention is a method for producing a composite container comprising a plastic inner container and a paper outer container, wherein the bottom of the outer container is inserted into a bottom mold for molding the bottom of the composite container. a recess is provided that, the outer container mounting step of said outer container instrumentation wear the bottom mold by inserting the bottom of the outer container in the recess, the preform holding step of holding the heated preform to be the inner container A preform insertion step of inserting the preform inside the outer container held by the bottom mold, and a mold combining step of combining a split mold for molding a portion other than the bottom of the composite container with the bottom mold. And a stretching step of inserting a stretching rod into the preform to stretch the preform, and a blowing step of pressurizing and injecting a fluid into the preform.
[0005]
The present invention is also characterized in that the mounting of the outer container to the bottom mold is performed by fitting a bottom of the outer container into the recess .
In the present invention, the bottom mold may further include a first opening provided on an inner wall of the recess, a second opening provided on an outer wall of the bottom mold, the first opening and the second opening. and a passage connecting the door, furthermore, a suction means for sucking air is provided through the second opening, the mounting of the outer container to the bottom mold, the bottom of the outer container is inserted in the recess the The air is sucked from the first opening through the second opening and the passage by the suction means .
The present invention is also characterized in that the first opening is provided on a side wall of the depression.
The present invention is also characterized in that a flexible material that is in contact with an outer surface of the outer container is mounted on a side wall of the depression.
The present invention is also characterized in that the flexible material is rubber.
[0006]
The present invention is also characterized in that an adhesive is applied to the inner surface of the outer container.
The present invention is also characterized in that the plastic inner container is made of polyethylene terephthalate.
The present invention is also characterized in that the fluid is air.
[0007]
[Action]
The outer container is attached to the bottom mold by inserting the bottom thereof into the recess of the bottom mold, and the preform serving as the inner container is accommodated at a predetermined position in the outer container attached to the bottom mold.
In that state, the split mold that forms a part other than the bottom of the composite container is united with the bottom mold, and a stretching rod is inserted into the preform to stretch the preform, and fluid is injected under pressure into the preform. Is done.
As a result, the preform expands, and its outer surface closely contacts the inner surface of the outer container to become an inner container, and a composite container consisting of the inner container and the outer container is manufactured.
[0008]
【Example】
Next, examples of the present invention will be described.
First, the composite container manufactured by the present invention will be described.
5A is a plan view of the composite container, FIG. 5B is a front view thereof, and FIG. 5C is a bottom view thereof.
The composite container 70 includes a bottom portion 50, a body portion 52, a mouth portion 56, and a shoulder portion 54 between the body portion 52 and the mouth portion 56.
The bottom 50 is substantially square, and the cross section of the body 52 is correspondingly substantially square.
The shoulder 54 has a narrower cross-sectional area as it goes upward, and at the narrowest point, connects to a mouth 56 having a cylindrical cross-section.
The outside around the bottom 50 and the outside of the torso 52 and the shoulder 54 are each made of a paper outer container (also called a carton) 58, while the bottom 50 and the torso 52, the inside of the shoulder 54 and the mouth 56. Consists of an inner container 60 made of PET.
[0009]
Before being formed into a composite container, the paper outer container 58 has a shape as shown in FIG.
That is, the outer container 58 includes four body pieces 58d forming a vertically long rectangular parallelepiped, a shoulder piece 58a connected to the upper end of each body piece 58d, and a bottom piece connected to the lower end of each body piece 58. 58b, and one sheet of paper is bonded by a glue margin 58c.
Before the outer container 58 is mounted on the mold, as shown in FIG. 4 (B), the body piece 58d is crushed and flattened. The containers 58 are stacked and housed in the outer container storage section.
As shown in FIG. 5, the inner container 60 includes a bottom 50A, a body 52, and a shoulder 54A that form the inside of the bottom 50, the body 52, and the shoulder 54 of the composite container 70, and the mouth 56. And a flange 62 is formed in the mouth 56.
[0010]
Next, the bottom mold used in this embodiment will be described.
2A is a plan view of a bottom mold, FIG. 2B is a front view, and FIG. 2C is a bottom view.
The bottom mold 2 is a mold for molding the bottom portion of the composite container 70 shown in FIGS. 4 and 5, and is used for inserting the bottom 50 of the outer container 58 and holding the outer container 58. Dent 4.
The recess 4 has the same square shape as the cross-sectional shape of the outer container 58, and the size thereof is the same as or slightly larger than the cross-sectional size of the outer container 58.
The four side walls 4a of the depression 4 form side portions near the bottom of the body 52 of the composite container 70 shown in FIG. 5, and an opening 4b is formed in the center of each side wall 4a.
Further, on the bottom surface of the bottom mold 2, four openings 2a are formed at positions respectively corresponding to the four openings 4b, and the openings 4b and the corresponding openings 2a are connected by the passages 2b, respectively.
Although the center of the bottom of the depression 4 is slightly raised, it is necessary to dent the bottom 50A of the molded composite container 70 inside the container, thereby increasing the strength of the container bottom and resisting the weight of the contents. It is.
On the four outer walls 2c of the bottom die 2 parallel to the side walls 4a, horizontally long protruding pieces 6 are formed along the outer wall 2c.
These protruding pieces 6 are for fixing the bottom mold 2 to another mold in an accurate positional relationship when the bottom mold 2 is combined with another mold described later.
[0011]
Next, a mold other than the bottom mold 2 used in this embodiment, that is, a pair of split molds for forming a part of the body 52, the shoulder 54, and the mouth 56 of the composite container shown in FIG. 5 will be described.
Since the pair of split molds is symmetrical, only one of them will be described.
3A shows a plan view of the split mold, FIG. 3B shows a front view thereof, and FIG. 3C shows a bottom view thereof.
The mold surface 20A of the split mold 20 has a concave portion 21 corresponding to the shape of the composite container 70, a concave portion 28 into which the bottom die 2 is fitted, and the like.
The concave portion 21 is composed of two mutually perpendicular wall surfaces 22 that form two adjacent outer surfaces of the body 52 of the composite container 70 and a wall surface 24 that forms the outer surface of the shoulder 54.
The depression 26 formed in the upper end surface of the split mold 20 is a portion where the flange 62 of the mouth 56 is arranged when the preform of the composite container 70 is mounted on the mold.
The recess 28 is a space where the bottom mold 2 is fitted when the bottom mold 2 is combined with the bottom mold 2. When combined with the bottom mold 2, the protruding piece 6 of the bottom mold 2 fits into a groove 28 a formed on the wall surface of the recess 28.
As shown in FIG. 1, a holder 92 composed of left and right divided bodies is united on the split mold 20, and the upper part of the preform 34 held by the holding means 94 is disposed inside the holder 92. As the holder 92 and the holding means 94, well-known holders and means used in stretch blow molding are used, and therefore detailed description is omitted.
[0012]
In the method for manufacturing the composite container 70 of this embodiment, stretch blow molding is performed using such a mold.
Hereinafter, description will be made with reference to the process chart of FIG.
Many outer containers 58 are accommodated in the container accommodating portion 32 in the flat state shown in FIG. 4B, and in the process A, one outer container 58 is taken out from the container accommodating portion 32, and It is formed into a box as shown in FIG. 4A by the outer container forming means (not shown).
At this time, the shoulder piece 58a and the bottom piece 58b are also bent inward by the outer container forming means.
The inner surface of the outer container 58 is coated with an adhesive which is brought into a tacky state by heating and exhibits an adhesive effect.
[0013]
In step B, the outer container 58 thus formed in a box shape is transported to the position of the bottom die 2 by a transporting means (not shown).
The bottom mold 2 is attached to a rotating mechanism (not shown) with its dent 4 facing downward. When the rotating mechanism stops at the position P1, the bottom of the outer container 58 that has been conveyed, that is, The portion near the bottom of the body piece 58 and the bottom piece 58b are attached to the bottom mold 2 while being inserted into the recess 4 of the bottom mold 2.
At this time, the suction means (not shown) is sucking air through the opening 2a of the bottom mold 2 and thus through the passage 2b. As a result, the portions of the attached outer container 58 near the bottom of the body piece 58 are respectively Is sucked into the opening 4b in the side wall of the depression 4.
This ensures that the outer container 58 is mounted and held on the bottom mold 2 (step C, ie, the outer container mounting step of the present invention).
Thereafter, the rotation mechanism rotates counterclockwise, and the bottom mold 2 and the outer container 58 are both circularly moved.
Then, when the bottom mold 2 reaches the position P2 immediately above the position P1, that is, with the outer container 58 on the bottom mold 2 facing upward, the rotation mechanism stops.
[0014]
On the other hand, when the outer container 58 is taken out of the outer container housing portion 32 and is formed in a box shape as described above, the preform 34 of the composite container is heated to about 90 ° C. Is transported to the holding means 94 installed in the apparatus, and is held by the holding means 94 with the opening facing upward (step D, ie, a preform holding step).
[0015]
Thereafter, in step E, the bottom mold 2 at the position P2 is moved upward by a lifting / lowering means (not shown), and the preform 34 is inserted into a predetermined position in the outer container 58 mounted on the bottom mold 2. Then, it stops in the housed state (preform insertion step).
In addition, the preform 34 is a bottomed preform made of PET, and is manufactured by injection molding or extrusion blow molding.
[0016]
Next, the pair of split dies 20 are moved horizontally from both sides of the outer container 58 toward the outer container 58 by driving means (not shown), and the bottom die 2 is accommodated in the recess 28 thereof. 2 (mold combining step).
Similarly, the pair of holders 92 are also united.
At this time, the outer surface of the outer container 58 mounted on the bottom mold 2 is substantially in close contact with the corresponding wall surfaces 22 and 24 of the split mold 20.
FIG. 1 shows only one of the pair of split dies 20. Actually, the other split mold is disposed in front of the sheet so as to face the split mold 20 in the figure.
Therefore, the pair of split dies 20 are initially arranged opposite to each other with a certain distance across the plane of the paper, and then approached to each other by the above-mentioned driving means, and united at the position of the plane of the paper.
When the bottom mold 2 is combined with the bottom mold 2, the four projecting pieces 6 of the bottom mold 2 are fitted into the grooves 28a of the split mold 20, respectively. As a result, the positional relationship between the split mold 20 and the bottom mold 2 is accurately determined. Then, the bottom mold 2 is fixed to the pair of split molds 20.
[0017]
When the uniting of the molds is completed, a predetermined stretching rod is inserted into the inside of the preform 34 through the mouth 56 of the preform 34, and the preform 34 is stretched in the major axis direction by the stretching rod (stretching step). Air is injected into the preform 34 from the mouth 56 under pressure and the preform 34 expands in the mold and thus in the outer container 58.
As a result, the inner container 60 is formed and completed, and the outer surface thereof is in close contact with the inner surface of the outer container 58 (blow process).
At this time, the adhesive applied to the inner surface of the outer container 58 is heated and melted by the high-temperature inner container 60 to develop adhesiveness, so that the inner surface of the outer container 58 and the outer surface of the inner container are bonded to each other. Glued by the agent.
Thereafter, the molds 2, 20, and 92 are released, and the completed composite container 70 shown in FIG. 5 is taken out.
[0018]
In the method of manufacturing a composite container according to the present invention, as described above, the outer container 58 is held in the bottom mold 2 in advance, the molds are combined in that state, and then the stretching step and the blowing step are performed. Was formed to obtain a composite container 70.
Therefore, this manufacturing method does not require any special components or devices for inserting the outer container 58 into the mold.
Further, since the outer container 58 is directly mounted in the mold, the outer container 58 can be accurately arranged, which is effective in improving the production yield.
[0019]
Further, in this manufacturing method, since the outer container 58 is also inserted into the mold and the inner container 60 is blow-molded, the inner container 60 is formed and simultaneously combined with the outer container 58.
Therefore, as compared with a method in which the inner container 60 is molded in a mold and then the outer container 58 is attached by some method, the number of steps is reduced, and the degree of adhesion between the inner container 60 and the outer container 58 is extremely high. Thus, a high-strength composite container 70 is obtained.
[0020]
In the above-described embodiment, the bottom mold 2 is provided with the depression 4, the opening 4b, the passage 2b, and the opening 2a as the mounting means for the outer container 58. However, the size of the depression 4 alone can be appropriately set. By doing so, the outer container 58 can be held by the frictional force between the outer surface of the outer container 58 and the side wall of the depression 4.
Further, it is also possible to increase the frictional force by attaching a thin plate of a flexible material such as rubber to the side wall of the depression 4 so that the outer container 58 can be held more reliably.
[0021]
Further, in the embodiment, the inner container 60 is made of PET, but the present invention is of course applicable even if the inner container 60 is made of a plastic other than PET.
The fluid to be pressurized and injected into the preform 34 may be any fluid that can expand the preform. Therefore, various gases other than air can be used, and further, a liquid can be used. .
In this embodiment, the composite container 70 having a square cross section is manufactured. However, this is merely an example, and the shape of the composite container 70 is arbitrary.
[0022]
【The invention's effect】
As described above, in the method for manufacturing a composite container according to the present invention, the outer container is attached and held in advance to the bottom mold, and the preform serving as the inner container is disposed inside the outer container, and in that state, another preform is used. The molds were combined and blow molding was performed.
Therefore, no special parts or devices are required for inserting the outer container into the mold.
Further, since the outer container is directly mounted on the mold, the outer container can be accurately arranged, which is effective for improving the production yield. Therefore, a composite container can be manufactured at low cost.
In addition, since the composite container can provide sufficient strength even if the amount of plastic used is reduced, the composite container is widely used as a container for liquids such as drinking water and liquor, or as a container for various solids and powders. By doing so, the problem of environmental pollution can be mitigated.
The present invention contributes to solving environmental problems by enabling the composite container to be manufactured at low cost.
[Brief description of the drawings]
FIG. 1 is a process chart showing an example of a process for producing a composite container based on a method for producing a composite container according to the present invention.
2 (A) is a plan view of a bottom mold among dies used in the manufacturing process of FIG. 1, FIG. 2 (B) is a front view thereof, and FIG. 2 (C) is a bottom view thereof.
3A is a plan view showing a pair of split dies among dies used in the manufacturing process of FIG. 1, FIG. 3B is a front view, and FIG. 3C is a bottom view.
4A is a perspective view showing an outer container used in the manufacturing process of FIG. 1, and FIG. 4B is a front view thereof.
5A is a plan view showing a composite container, FIG. 5B is a side view of the same, and FIG. 5C is a bottom view.
[Explanation of symbols]
2 Bottom mold 2a, 4b Opening 2b Passage 2c Outer wall 4a Side wall 20 Split mold 22, 24 Wall 28 Depression 28a Groove 32 Outer container storage part 34 Preform 36 Composite container 50 Bottom 52 Body 54 Shoulder 56 Mouth 58 Outer container 60 Inner container

Claims (10)

A method for producing a composite container comprising a plastic inner container and a paper outer container,
A bottom mold for molding the bottom of the composite container is provided with a recess into which the bottom of the outer container is inserted,
Inserting the bottom of the outer container into the recess and mounting the outer container on the bottom mold ,
Next, the heated preform serving as the inner container is arranged inside the outer container,
Next, a split mold for molding a portion other than the bottom portion of the composite container is united with the bottom mold,
Then, the preform was stretched by inserting a stretching rod into the preform, and a fluid was injected under pressure into the preform,
A method for producing a composite container, comprising: A method for producing a composite container comprising a plastic inner container and a paper outer container,
A bottom mold for molding the bottom of the composite container is provided with a recess into which the bottom of the outer container is inserted,
An outer container mounting step of instrumentation wearing the outer container to the bottom mold by inserting the bottom of the outer container in the recess,
A preform holding step of holding a heated preform that becomes the inner container,
A preform insertion step of inserting the preform inside the outer container held by the bottom mold,
A mold combining step of combining a split mold for molding a portion other than the bottom portion of the composite container with the bottom mold,
A stretching step of stretching the preform by inserting a stretching rod into the preform,
A blow step of pressurizing and injecting a fluid into the preform,
A method for producing a composite container, comprising: The method for manufacturing a composite container according to claim 1 , wherein the mounting of the outer container on the bottom mold is performed by fitting a bottom portion of the outer container into the recess . The bottom mold has a first opening provided on an inner wall of the depression, a second opening provided on an outer wall of the bottom mold, and a passage connecting the first opening and the second opening. Further, suction means for sucking air through the second opening is provided, and mounting of the outer container on the bottom mold is such that the bottom of the outer container is inserted into the depression, and the suction means method of manufacturing a composite container according to claim 1 or 2, wherein is carried out by air is sucked from the first opening through the second opening and the passageway. The method according to claim 4, wherein the first opening is provided on a side wall of the depression. The method for manufacturing a composite container according to claim 3 , wherein a flexible material that is in contact with an outer surface of the outer container is mounted on a side wall of the depression. The method according to claim 6, wherein the flexible material is rubber. The method according to claim 1, wherein an adhesive is applied to an inner surface of the outer container. The method according to claim 1 or 2, wherein the plastic inner container is made of polyethylene terephthalate. 3. The method according to claim 1, wherein the fluid is air.

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