JPH08276958A - Manufacture of composite container - Google Patents

Abstract

PURPOSE: To produce composite containers with good yields to reduce problems of environmental contamination by mounting an outer container on a bottom mold in advance and performing blow-molding with a preform to be an inner container placed inside the outer container. CONSTITUTION: An outer container 58 formed into a box during processes A, B is mounted on a bottom mold 2 so that the bottom of the container 58 is, during a process C, inserted into a recess 2 of the bottom mold 2 and suction- held at an opening of a side wall of the recess 4. Thereafter, during a process E, the bottom mold 2 positioned at P2 is moved upward, a preform 34 is inserted into the container 58 mounted on the bottom mold 2, a pair of split molds 20 are horizontally moved from both sides of the outer container 58, the bottom mold 2 is put into a recess 28 of the molds 20, and the molds 20 are unified. After the molds 20 are unified, a drawing rod is inserted inside the preform through a mouth 56 of the preform 34 to be drawn along a long axis, and since with air pressure-injected, the preform 34 expands in the mold, an inner container is molded to be in tight contact with an internal face of the outer container 58, thereby completing a composite container.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite container consisting of a plastic inner container and a paper outer container.

[0002]

2. Description of the Related Art Polyethylene terephthalate (hereinafter also referred to as PET) containers, so-called PET bottles, are widely used as containers for selling drinking water. PE
Since the T bottle is lighter in weight than the glass container, it is easy to transport and store, and is advantageous in terms of manufacturing cost. However, if it is discarded as it is or buried in the soil, it will not dissolve in water, will not oxidize, and will not be decomposed by microorganisms, and therefore will maintain its form for a long time. Moreover, PET bottles are consumed in extremely large quantities. This applies not only to PET bottles, but to all plastic containers, and the resulting environmental pollution is a serious problem.

[0003]

Problems to be Solved by the Invention 1 to alleviate this problem
One way 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 will decrease, and it will no longer function as a container. Therefore, attention has been paid to a composite container in which paper is combined. This composite container is formed by covering a plastic inner container with a paper outer container, and compensates for the strength decrease of the inner container due to the reduction of the amount of plastic used by the strength of the paper outer container. . Needless to say, paper is easily broken down by water, reduced to plant fibers, and decomposed by microorganisms. Therefore, the composite container using paper is effective in mitigating the problem of environmental pollution. Therefore, it is an object of the present invention to provide a method for manufacturing a composite container, which makes it possible to manufacture a composite container having such advantages at low cost.

[0004]

To achieve the above object, the present invention is a method for producing a composite container comprising an inner container made of plastic and an outer container made of paper, wherein the bottom of the composite container is The outer container is attached to the bottom mold to be molded, then the heated preform to be the inner container is placed inside the outer container, and then the split mold for molding the portion other than the bottom portion of the composite container is used. It is characterized in that it is integrated with the bottom mold, and then a stretching rod is inserted into the preform to stretch the preform, and a fluid is injected under pressure into the preform. Further, the present invention is a method for producing a composite container consisting of a plastic inner container and a paper outer container, comprising a predetermined mounting means for mounting the outer container, the bottom of the composite container An outer container mounting step of mounting the outer container on the bottom mold to be molded by the mounting means, a preform holding step of holding the heated preform of the inner container by a predetermined holding means, and mounting on the bottom mold. At a predetermined position in the outer container, a preform accommodating step of accommodating the preform, 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, It is characterized by including a stretching step of inserting a stretching rod into the preform to stretch the preform and a blowing step of injecting a fluid into the preform under pressure.

The present invention is also characterized in that the bottom mold has a recess for fitting the bottom portion of the outer container as a mounting means for the outer container. The present invention also provides that the outer container mounting means has a first opening provided on an inner wall of the recess and a second opening provided on an outer wall of the bottom mold.
And an opening, a passage connecting the first opening and the second opening, and suction means for sucking air through the second opening. The present invention is also characterized in that the first opening is provided in a side wall of the recess. The present invention also provides, on the side wall of the depression,
A soft material is attached to the outer surface of the outer container. The present invention is also characterized in that the soft material is rubber.

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 invention is also characterized in that the fluid is air.

[0007]

The outer container is mounted on the bottom mold by the bottom mold mounting means, and the preform to be the inner container is housed at a predetermined position in the outer container mounted on the bottom mold. In that state,
A split mold forming a part other than the bottom of the composite container is united with the bottom mold, and a drawing rod is inserted into the preform to draw the preform, and a fluid is injected under pressure into the preform. As a result, the preform expands and its outer surface comes into close contact with the inner surface of the outer container to form an inner container, and a composite container including an inner container and an outer container is manufactured.

[0008]

Next, an embodiment 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 of the same,
(C) shows the same bottom view. This composite container 70 has a bottom 5
0, body 52, mouth 56, and body 52 and mouth 56
And a shoulder 54 between. The bottom portion 50 has a substantially square shape, and correspondingly, the body portion 52 has a substantially square cross section.
The cross-sectional area of the shoulder portion 54 becomes narrower as it goes upward, and at the narrowest point, it is connected to the mouth portion 56 having a cylindrical cross-section. The outside of the periphery of the bottom 50, the body 52, and the outside of the shoulder 54 each consist of an outer container (also called a carton) 58 made of paper, while the bottom 50 and the body 52, the inside of the shoulder 54 and the mouth 56. Is composed of a PET inner container 60.

The outer container 58 made of paper has a shape as shown in FIG. 4A before being molded into a composite container. That is, the outer container 58 includes four body pieces 58d that are vertically long rectangular parallelepipeds, shoulder pieces 58a that are connected to the upper ends of the body pieces 58d, and bottom pieces that are connected to the lower ends of the body pieces 58. 5
8b, and one sheet of paper is adhered at the margin portion 58c. Such an outer container 58 is flattened by crushing the body piece 58d as shown in FIG. 4 (B) before being attached to the mold. The containers 58 are stacked and stored in the outer container storage portion. As shown in FIG. 5, the inner container 60 includes a bottom portion 50A, a body portion 52A, and a shoulder portion 54A that form an inner portion of the bottom portion 50, the body portion 52 and the shoulder portion 54 of the composite container 70.
And a mouth portion 56, and a collar 62 is formed on the mouth portion 56.

Next, the bottom mold used in this embodiment will be described. 2A is a plan view of the bottom mold, FIG. 2B is a front view,
(C) shows a bottom view. This bottom mold 2 is a mold for molding the bottom portion of the composite container 70 shown in FIGS. 4 and 5, and for inserting the bottom portion 50 of the outer container 58 to hold the outer container 58. It has a recess 4. The recess 4 is a square having the same cross-sectional shape as the outer container 58, and the dimension thereof is the same as or slightly larger than the cross-sectional dimension of the outer container 58. Four side walls 4a of the depression 4
Is for molding the side portion of the composite container 70 shown in FIG.
b is formed. Further, on the bottom surface of the bottom mold 2, four openings 2 are provided at positions respectively corresponding to these four openings 4b.
a is formed, and the opening 4b and the corresponding opening 2a are connected by a passage 2b. The center of the bottom of the recess 4 is slightly raised, which is intended to make the bottom 50A of the molded composite container 70 recessed inside the container, thereby increasing the strength of the container bottom and counteracting the weight of the contents. Is. On the four outer walls 2c of the bottom die 2 parallel to the side walls 4a, laterally long protruding pieces 6 are formed along the outer walls 2c. These protruding pieces 6 are for fixing the bottom mold 2 to the other mold in an accurate positional relationship when the bottom mold 2 is combined with another mold described later.

A mold other than the bottom mold 2 used in this embodiment, that is, a pair of split molds for molding a part of the body portion 52, the shoulder portion 54, and the mouth portion 56 of the composite container shown in FIG. 5 will be described. To do. In addition, since the pair of split molds are symmetrical,
One of them will be described. FIG. 3A is a plan view of the split mold,
(B) shows the same front view, (C) shows the same bottom view. Split mold 20
The mold surface 20A is provided with a recess 21 corresponding to the shape of the composite container 70, a recess 28 into which the bottom mold 2 is fitted, and the like. The recess 21 is formed by two wall surfaces 22 which are orthogonal to each other and form two adjacent outer surfaces of the body 52 of the composite container 70.
And the wall surface 24 that forms the outer surface of the shoulder portion 54. The recess 26 formed on the upper end surface of the split mold 20 is a portion where the collar 62 of the mouth portion 56 is arranged when the preform of the composite container 70 is mounted on the mold. The concave portion 28 is a space into which the bottom mold 2 is fitted when it is united with the bottom mold 2.
When united with the bottom die 2, the protruding piece 6 of the bottom die 2 is fitted into the groove 28a formed in the wall surface of the recess 28. In addition, split mold 2
As shown in FIG. 1, a holder 92 composed of left and right divided bodies is united on the top of the preform 34, and the upper portion of the preform 34 held by the holding means 94 is arranged inside the holder 92. As the holding means 94, known holders and means used in stretch blow molding are used, and thus detailed description thereof will be omitted.

In the method of manufacturing the composite container 70 of this embodiment, stretch blow molding is performed using such a mold. Less than,
This will be described with reference to the process chart of FIG. The outer container 58 is shown in FIG.
A large number are stored in the container storage portion 32 in the flat state shown in (B).
The outer containers 58 are taken out and formed into a box shape 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 that is brought into an adhesive state by heating and exhibits an adhesive effect.

In step B, the outer container 58 thus formed in a box shape is conveyed to the position of the bottom mold 2 by a conveying means (not shown). The bottom mold 2 is attached to a rotation mechanism (not shown) with the recess 4 facing downward, and when the rotation mechanism stops at the position P1, the bottom of the outer container 58 that has been conveyed, that is, Body piece 58
The bottom portion and the bottom piece 58b are inserted into the recess 4 of the bottom mold 2 and attached to the bottom mold 2. At this time, the suction means (not shown) sucks air through the opening 2a of the bottom mold 2, and thus through the passage 2b, so that the parts of the outer container 58 mounted on the body 58 near the bottom are respectively sucked. , Is adsorbed to the opening 4b on the side wall of the depression 4. As a result, the outer container 58 is securely mounted and held on the bottom mold 2 (step C, that is, the outer container mounting step of the present invention). afterwards,
The rotating mechanism rotates counterclockwise, and the bottom mold 2 and the outer container 58 are circularly moved together. Then, when the bottom mold 2 reaches the position P2 immediately above the position P1, that is, in a state where the outer container 58 on the bottom mold 2 faces upward, the rotation mechanism stops.

On the other hand, as described above, when the outer container 58 is taken out from the outer container accommodating section 32 and formed into a box shape, the preform 34 of the composite container is heated to about 90 ° C. and then positioned. Holding means 94 installed on the upper part of P2
And is held by the holding means 94 with the mouth upward (step D, that is, the preform holding step).

Then, in step E, the bottom mold 2 at the position P2 is moved upward by the lifting means (not shown), and the preform 34 is placed at a predetermined position in the outer container 58 mounted on the bottom mold 2. And is stopped in the accommodated state (preform inserting step). The preform 34
Is a PET bottomed preform for injection molding,
It was produced by extrusion blow molding.

Next, the pair of split molds 20 are horizontally moved from both sides of the outer container 58 toward the outer container 58 by a driving means (not shown), and the bottom mold 2 is accommodated in the recess 28 thereof. , The bottom mold 2 is combined (mold combination process). Similarly, the pair of holders 92 are also combined. At this time, the outer surface of the outer container 58 mounted on the bottom mold 2 is in close contact with the corresponding wall surfaces 22 and 24 of the split mold 20. In FIG. 1, only one of the pair of split molds 20 is shown. Actually, the other split mold is arranged in front of the paper surface so as to face the split mold 20 in the figure. Therefore, the pair of split molds 20 are initially arranged in front and back so as to face each other with a certain distance therebetween with respect to the paper surface, and thereafter, they are brought closer to each other by the driving means and united at the position on the paper surface. When the bottom die 2 is combined with the bottom die 2, the four protruding pieces 6 of the bottom die 2 are fitted into the grooves 28a of the split die 20, respectively, and as a result, the positional relationship between the split die 20 and the bottom die 2 is accurately determined. And bottom mold 2
Are fixed to the pair of split molds 20.

When the molds are combined, the preform 34
A predetermined stretch rod is inserted into the preform 34 through the mouth portion 56 of the preform 34, and the stretch rod pushes the preform 34.
Is stretched in its major axis direction (stretching step), and at the same time, the mouth portion 5
Air from 6 is injected under pressure into the preform 34 and the preform 34 expands in the mold and thus in the outer container 58. As a result, the inner container 60 is molded and completed, and the outer surface thereof comes into close contact with the inner surface of the outer container 58 (blowing process). Also, at this time, by the high temperature inner container 60,
The adhesive applied to the inner surface of the outer container 58 is heated and melted to develop adhesiveness, so that the inner surface of the outer container 58 and the outer surface of the inner container are bonded by this adhesive. After that, the molds 2, 20, and 92 are released, and the completed composite container 70 shown in FIG. 5 is taken out.

In the method for manufacturing a composite container according to the present invention, as described above, the outer container 58 is held in advance in the bottom mold 2, the molds are combined in this state, and then the stretching process and the blowing process are performed. The inner container 60 was molded to obtain the composite container 70. Therefore, this manufacturing method does not require a special part or device for inserting the outer container 58 into the mold. Moreover, 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 manufacturing yield.

Further, in this manufacturing method, since the outer container 58 is also inserted into the mold and the inner container 60 is blow-molded,
Simultaneously with the molding of the inner container 60, the compounding with the outer container 58 is also performed. Therefore, the number of steps is smaller than the method of mounting the outer container 58 by some method after molding the inner container 60 with a mold, and the degree of adhesion between the inner container 60 and the outer container 58 is very high. Therefore, the high-strength composite container 70 is obtained.

In the embodiment described above, the outer container 58
As the mounting means for the bottom mold 2, the recess 4, the opening 4b, the passage 2b, and the opening 2a are provided. However, even if only the recess 4 is used, the size of the outer container 5 can be appropriately set.
8 by the frictional force between the outer surface of 8 and the side wall of the depression 4.
8 can be held. Further, by attaching a thin plate of a flexible material such as rubber to the side wall of the recess 4, it is possible to increase the frictional force so that the outer container 58 is held more reliably.

In the embodiment, the inner container 60 is made of PET.
However, even if the inner container 60 is made of plastic other than PET, the present invention is of course applicable. The fluid to be injected under pressure into the preform 34 is
Any material that can expand the preform may be used. Therefore, various gases other than air can be used, and liquid can also be used. Further, in this embodiment,
The composite container 70 having a square cross section is manufactured, but this is merely an example, and the shape of the composite container 70 is arbitrary.

[0022]

As described above, in the method for manufacturing a composite container according to the present invention, the outer mold is previously mounted and held on the bottom mold, and the preform to be the inner container is arranged inside the outer container. In that state, other molds were combined and blow molding was performed. Therefore, no special parts or devices are required to insert the outer container into the mold. Further, since the outer container is directly attached to the mold, the outer container can be accurately arranged, which is effective in improving the manufacturing yield. Therefore, the composite container can be manufactured at low cost. In addition, since the composite container can obtain 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 alleviated. The present invention contributes to the solution of environmental problems by enabling the composite container to be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a process drawing showing an example of a process for producing a composite container based on the method for producing a composite container according to the present invention.

2A is a plan view of a bottom die of the molds used in the manufacturing process of FIG. 1, FIG. 2B is a front view thereof, and FIG. 2C is a bottom view thereof.

3A is a plan view showing a pair of split molds of the mold 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 thereof.

[Explanation of symbols]

 2 bottom type 2a, 4b opening 2b passage 2c outer wall 4a side wall 20 split type 22, 24 wall surface 28 recess 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)

[Claims] 1. A method for producing a composite container comprising an inner container made of plastic and an outer container made of paper, wherein the outer container is attached to a bottom mold for molding the bottom of the composite container, and then the A heated preform to be an inner container is placed inside the outer container, and then a split mold for molding a portion other than the bottom portion of the composite container is united with the bottom mold, and then stretched in the preform. A method for producing a composite container, wherein a rod is inserted to extend the preform, and a fluid is injected under pressure into the preform. 2. A method for manufacturing a composite container comprising an inner container made of plastic and an outer container made of paper, comprising a mounting means for mounting the bottom of the outer container, and a bottom for molding the bottom of the composite container. An outer container mounting step of mounting the outer container to the mold by the mounting means, a preform holding step of holding a heated preform to be the inner container, and an inner side of the outer container held in the bottom mold. A preform inserting step of inserting the preform, 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, and a drawing rod is inserted into the preform to insert the preform. A method of manufacturing a composite container, comprising: a stretching step of stretching the reform; and a blowing step of injecting a fluid into the preform under pressure. 3. The method for producing a composite container according to claim 1, wherein the bottom mold has a recess for fitting the bottom portion of the outer container as a mounting means for the outer container. 4. The outer container mounting means includes a first opening provided in an inner wall of the recess, a second opening provided in an outer wall of the bottom mold, the first opening, and the first opening. The method for manufacturing a composite container according to claim 3, further comprising: a passage that connects the second opening and a suction unit that sucks air through the second opening. 5. The method of manufacturing a composite container according to claim 4, wherein the first opening is provided in a side wall of the recess. 6. The method of manufacturing a composite container according to claim 3, wherein a soft material that is in contact with the outer surface of the outer container is attached to the side wall of the recess. 7. The method for manufacturing a composite container according to claim 6, wherein the soft material is rubber. 8. The method of manufacturing a composite container according to claim 1, wherein an adhesive is applied to the inner surface of the outer container. 9. The method for producing a composite container according to claim 1, wherein the inner container made of plastic is made of polyethylene terephthalate. 10. The method for manufacturing a composite container according to claim 1, wherein the fluid is air.