JPH09201872A - Blow molded composite container and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blow molded composite container not having the possibility of the liquid leakage caused by the breakage of an inside blow molded container and capable of reducing the amt. of a plastic material, in the blow molded composite container obtained by preliminarily inserting a shape retaining cylindrical member made of paper into a blow mold and integrally performing biaxial stretching blow molding, by preventing the stretching magnification of biaxial stretching blow molding of the corner part of the bottom surface or side surface of the inside blow molded container easy to be excessively stretched from becoming 4.5 times or more. SOLUTION: A shape retaining cylindrical member 10 made of paper is preliminarily inserted into a blow mold equipped with a side surface mold and a bottom surface mold so as to be fitted and fixed to the gap mold member provided to the bottom surface mold to integrally perform biaxial stretching blow molding to obtain a blow molded composite container wherein curved surface parts 21, 21, 22, 22 forming a gap between an inside blow molded container 20 and the outside shape retaining cylindrical member 10 are provided to the corner parts of the bottom surface or side surface of the inside blow molded container 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention inserts a shape-maintaining tubular body (10) made of paper in advance into a blow molding die for accommodating various beverages, oils and fats, liquid detergents, etc. The present invention relates to improvements in blow molded composite containers that have been axially stretch blow molded.

[0002]

2. Description of the Related Art Conventionally, polypropylene (PP) or polyester, which holds various beverages, oils and fats, liquid detergents, etc.
Various biaxially stretch blow molded plastic containers such as (PET) and polyvinyl chloride (PVC) are widely used.

However, recently, in connection with the problems of waste disposal related to the global environment and the problem of exhaustion of petroleum resources, the plastic containers such as polypropylene, polyester, polyvinyl chloride, etc. are made thinner by reducing the wall thickness of these various plastic containers. In order to reduce the amount of, for example, as shown in FIG.
A blow-molded composite container in which a paper-made bottomed box body (51) is previously inserted into a blow-molding die and integrally biaxially stretch-blow-molded, or as shown in FIG. 4 (B). In the mold,
A blow molding composite container in which a paper cylindrical body (52) is inserted in advance and integrally biaxially stretch blow molded is used.

In the blow-molded composite container shown in FIGS. 4 (A) and 4 (B) for accommodating various beverages, oils and fats, liquid detergents, etc., an outer bottomed box (51) made of paper or Cylindrical (52)
However, the shape and the self-supporting property of the blow-molded composite container are retained, and the inner blow-molded container (20) retains the liquid-tightness of the contents of the blow-molded composite container.

[0005]

However, in the above-mentioned conventional blow-molded composite container shown in FIGS. 4 (A) and 4 (B), the inner blow-molded container (20) is made thinner to reduce the wall thickness. If you try to reduce the amount of plastic materials,
If the draw ratio of the biaxial stretch blow molding at the bottom corners and side corners of the inner blow molding container (20) is overstretched to 4.5 times or more, whitening may occur and the strength may suddenly decrease. hand,
The blow molding container (20) inside may be broken and leaked from the corners of the bottom surface and the corners of the side surfaces that have been stretched to a draw ratio of 4.5 or more.

By the way, an object of the present invention is to provide an inner blow-molded container (20) which is likely to be overstretched when the thickness of the inner blow-molded container (20) is reduced in the conventional blow-molded composite container and the like. ) It is possible to prevent the draw ratio of the biaxial stretch blow molding of the bottom corners and side corners of 4.5) from becoming more than 4.5 times, and the inner blow molding container (20) may break and leak liquid. Another object of the present invention is to provide a blow-molded composite container that does not have the above-mentioned property and can reduce the amount of plastic material.

[0007]

As shown in FIGS. 1 and 2, the blow-molded composite container of the present invention has a shape-retaining cylinder (10) made of paper inserted in advance in a blow-molding die. , Two together
In a blow molded composite container that has been axially stretch blow molded, a curved surface portion (21, 21) is provided at a corner of the bottom surface of the inner blow molded container (20) to form a gap between the outer shape retaining cylinder (10). It is a blow molded composite container.

In addition, the blow molded composite container of the present invention comprises:
In the case where the paper shape-retaining cylinder (10) is a rectangular tube-shaped shape-retaining cylinder (10), as shown in FIGS. At the side corner of (20),
A curved surface (2
2, 22) is a blow-molded composite container.

Further, the blow-molded composite container of the present invention is a blow-molded composite container provided with voids so that the stretch ratio of the inner blow-molded container (20) is within 4.5 times in all parts. It is a container.

Further, in the method for manufacturing a blow-molded composite container of the present invention, as shown in FIG. 3, side molds (30, 30) and bottom molds (4) are used.
(0) and a void-shaped mold member (41, 41, 4) in which a paper shape-retaining cylinder (10) is provided in advance on the bottom mold (40) in a blow molding mold including
(2,42) is fitted and fixed and inserted, and is integrally biaxially stretch blow molded to obtain the inner blow molding container (2
At the bottom corners or side corners of (0), the outer shape retaining cylinder (10)
The method for producing a blow-molded composite container is provided with curved surface portions (21, 21, 22, 22) that are voids between and.

[0011]

In the blow-molded composite container of the present invention, the shape-retaining cylinder (10) made of paper is previously inserted into the blow-molding die, and the blow-molded composite container is integrally biaxially stretch-blow-molded. When the thickness of the inner blow-molded container (20) is reduced, the bottom corners or side corners of the inner blow-molded container (20), which are easily overstretched, and the outer shape-retaining cylinder (10) By providing the curved surface portions (21, 21, 22, 22) with spaces between them, the stretching ratio of the biaxial stretch blow molding at the bottom corner portion or the side corner portion of the inner blow molding container (20) is 4%. Provided is a blow-molded composite container, which prevents the blow-molded container (20) inside from being broken by 5 times or more, does not have a risk of liquid leakage and further reduces the amount of plastic material. it can.

Further, in the method for producing a blow-molded composite container according to the present invention, a shape-maintaining cylinder made of paper is previously placed in a blow-molding die having side molds (30, 30) and bottom mold (40). (Ten)
Is fitted and fixed to the void mold members (41, 41, 42, 42) provided in the bottom die (40), and is integrally biaxially stretch blow molded. Blow Molded Container (2
At the bottom corners or side corners of (0), the outer shape retaining cylinder (10)
It is possible to stably provide curved surface portions (21, 21, 22, 22) having a space between and.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 3 (A) shows a blow molding die having a side surface mold (30, 30) and a bottom surface mold (40) according to the present invention.
As shown in, on the upper surface side of the outer peripheral portion of the bottom mold (40), between the outer shape retaining cylinder (10) (cylindrical shape retaining cylinder (10)
In the case of (4), a void-shaped mold member (41) having a curved surface (21, 21) corresponding to a ring-shaped (rectangular tubular shape-retaining tubular body (10) ring-shaped void having tetrahedrons at the corners) , 41) is provided, and a gap (a, a corresponding to the thickness of the shape-retaining tubular body (10) made of paper is provided between the cavity mold member (41, 41) and the side mold (30, 30). A blow molding die provided with a), the side mold (30, 30) and the bottom mold.
In a blow molding die having (40), a shape-holding cylinder (10) made of paper is previously provided in the bottom die (40), and a void die member (41, 4) is provided.
It can be fitted and positioned in 1), firmly fixed and inserted in the gap (a, a), and integrally biaxially stretch blow molded. At the corner of the bottom surface of the container (20), a curved surface portion (21, 21) that forms a gap between the outer shape-retaining cylinder (10) and the curved surface of the ring-shaped void mold member (41, 41) ( It can be installed stably according to (21, 21).

In addition, the side mold (30, 30) and the bottom mold of the present invention
In the blow molding die including (40), the shape-holding cylinder (10) made of paper is a rectangular shape-keeping cylinder (1) made of paper.
0), as shown in FIG. 3 (B), the outer shape-holding cylinder is provided above the tetrahedron at the corner of the void die member (41, 41) provided in the bottom die (40) described above. Corresponding to the triangular prism-shaped void in the corner between the body (10), the void mold member (42, 42) having a curved surface (22, 22) is provided, and this void mold member (42, 42) A blow molding die in which a gap (b, b) corresponding to the thickness of the paper shape retaining cylinder (10) is also provided between the side mold (30, 30). (30, 30) and a bottom mold (40) in a blow molding mold, a paper shape-holding cylinder (10) in advance, a void mold member (42, provided on the bottom mold (40) 42) is fitted and positioned, firmly fixed and inserted in the gap (b, b), and similarly, it is possible to integrally perform biaxial stretch blow molding. A curved surface that forms a gap between the outer side of the blow molding container (20) and the outer shape-retaining cylinder (10). (22, 22) and, in accordance with the curved surface (22, 22) of the triangular-shaped gap die member (42, 42), can be stably provided by.

[0015]

EXAMPLE FIG. 1 (A) is a perspective view of a blow-molded composite container according to an embodiment of the present invention, and FIG. 1 (B) is a blow-molded composite container according to an embodiment of the present invention. Tube (1
It is a top view of the blank of 0). 2 is a sectional view of the blow-molded composite container shown in FIG. 1 (A) taken along the line XX, and FIG. 2 (B) is a sectional view taken along the line YY. 2C is a cross-sectional view of the ZZ plane.

In the blow-molded composite container of this embodiment,
For the shape retention cylinder (10) made of paper,
Through (undotted dash-dot line, the same hereafter), paste margin piece (12)
With a rectangular side plate group (11,11,11,11,11) and a glue strip (1
4) A trapezoidal side shoulder plate group (13,13,13,13,13) with is a blank that is connected to each other and is water resistant.
Using 0 g / m ² coated cardboard, perform normal printing on the outer surface and apply the heat-sensitive adhesive on the inner surface, and perform the normal punching process using a punching die as shown in FIG. 1 (B). Shown shape holding cylinder made of paper
After producing the blank of (10), in a normal mechanical box making process (commonly referred to as a sack pasting process), an adhesive margin piece (12, 14) coated with an appropriate adhesive, side plates, side shoulder plates 1 (A), in the blow-molded composite container of the present embodiment, which has a rectangular parallelepiped shape in which (11, 13) is adhered and the length, width, and height are narrowed at 65 × 80 × 225 mm. A paper shape-holding cylinder (10) shown in FIGS. 2 (A), (B), and (C) was produced.

FIG. 3 is a sectional view of the blow molding composite container shown in FIG. 1 (A), and FIG. 3 (A) is a sectional view of the blow molding die corresponding to the XX section of FIG. 2 (A). FIG. 3 (B) is shown in FIG.
It is sectional drawing of a blow molding die corresponding to the YY cross section of (B).

That is, on the upper surface side of the outer peripheral portion of the bottom die (40), which corresponds to a ring-shaped space having tetrahedrons at four corners with the outer shape retaining cylinder (10), as shown in FIG. ), (B) is provided with a cavity mold member (41, 41) having a curved surface (21, 21), above the tetrahedron at the four corners of this cavity mold member (41, 41) By providing void mold members (42, 42) having curved surfaces (22, 22) shown in FIG. 3 (B), which correspond to the triangular prism-shaped voids at the four corners with the shape retaining tubular body (10), Each void mold member (41, 41,
42, 42) and the side mold (30, 30), a gap corresponding to the thickness (about 0.6 mm) of the paper shape retaining cylinder (10) shown in FIGS. 1 and 2.
In the blow-molded composite container of this embodiment provided with (a, a, b, b), side molds (30, 30) and bottom molds (30, 30) shown in FIGS.
A blow molding die having (0) and was prepared.

Next, using a normal biaxial stretch blow molding apparatus, a blow molding mold having side molds (30, 30) and bottom mold (40) shown in FIG. An air gap mold member (4) provided with a bottom shape (40) on the paper shape-retaining cylinder (10) shown in FIG.
1, 41, 42, 42) and positioned, and firmly fixed and inserted in the gaps (a, a, b, b), and the heat-preheated preform having a weight of 15 g (injection molded Polyethylene terephthalate (PET) with spout (23) (not shown) is set and integrally biaxially stretch blow molded, so that the bottom corner portion of the inner blow molded container (20) that is easily overstretched Or, in the side surface corner portion, a curved surface portion (21, 21, 22, 22) forming a gap between the outer shape-retaining cylinder (10) and a ring-shaped or triangular prism-shaped void mold member (41, 41, 42, 42) is provided stably according to the curved surface (21, 21, 22, 22), and the inner blow-molded container (20) made of polyethylene terephthalate has a weight of 15 g.
Containing 1000 ml of the liquid detergent of this example, FIG.
A blow-molded composite container with a spout (23) shown in (A) was produced.

In the method for producing a blow-molded composite container of this embodiment, the inner blow-molded container (20) which is easily overstretched is used.
By providing curved surface parts (21,21,22,22) at the corners of the bottom surface or corners of the side surface of the shape-keeping tubular body (10) to form an air gap between them, the blow-in The stretching ratio of the biaxial stretch blow molding of the bottom corner or the side corner of the molding container (20) is 3.2 times or less in the longitudinal direction and 3.9 times or less in the lateral direction, and is overstretched. It was possible to prevent it from becoming more than 5 times, no whitening of the bottom corners or side corners, deterioration of strength, etc. was observed, and the inner blow molding container (20) broke and leaked. A fearless blow molded composite container was obtained.

For comparison, the side molds (30, 30) and the bottom mold (40) similar to those in FIG. 3 except that the cavity mold members (41, 41, 42, 42) are not provided in the bottom mold (40). ) And a shape-retaining cylinder (10) made of paper shown in FIGS. 1 and 2 are inserted in advance into a blow molding die, and similarly, the preform (polyethylene terephthalate) having a weight of 15 g is softened by heating. Manufactured by the same method, and similarly subjected to biaxial stretch blow molding, the lateral biaxial stretch blow molding of the bottom corners of the four corners of the inner blow molding container (20) that is particularly easily overstretched. A blow-molded composite container was obtained in which the magnification became 4.7 times or more, whitening and the strength suddenly decreased, and the inner blow-molded container (20) was ruptured and the liquid leaked.

On the contrary, in order to make the draw ratio of the lateral biaxial stretch blow molding at the corners of the four corners of the inner blow molding container (20) which is particularly easily stretched to be 4.5 times or less. Blow provided with the side molds (30, 30) and the bottom mold (40) similar to those in FIG. 3, in which the above-mentioned bottom mold (40) is not provided with the void mold members (41, 41, 42, 42). A shape-retaining tubular body (10) made of paper shown in FIGS. 1 and 2 is inserted into a molding die in advance, and the preform (made of polyethylene terephthalate) having a weight of 18 g and being softened by heating.
It was necessary to set and to integrally perform biaxial stretch blow molding. That is, in the method for producing a blow-molded composite container of the present example, it was possible to reduce the weight of the inner blow-molded container (20) made of polyethylene terephthalate from 18 g to 15 g by about 17%. .

In the blow-molded composite container of this embodiment, the thickness of the inner blow-molded container (20) is reduced to
At the bottom corners or side corners of the inner blow-molded container (20) that is easily overstretched, curved surface portions (21, 21, 22, 22) that form a gap between the outer shape-retaining cylinder (10). Even if the shape retention and self-standing stability of the inner blow-molded container (20) are lacking due to the provision, it is made of 450 g / m ² coated cardboard with added water resistance and narrowed upward. A rectangular parallelepiped shape-retaining tubular body (10) is integrally biaxially stretch-blow-molded via a heat-sensitive adhesive applied on the inner surface side to accommodate 1000 ml of the liquid detergent of the present embodiment. The shape-retaining and self-standing stability of the blow-molded composite container with the spout (23) shown in A) is completely retained by the shape-retaining cylinder (10) in the shape of a rectangular parallelepiped whose outer upper side is narrowed. .

[0024]

As described above, in the blow molding composite container of the present invention, when the thickness of the inner blow molding container (20) is reduced, the inner blow molding is likely to be overstretched. The bottom surface corner or side surface corner of the container (20) has a curved surface portion (21,
By providing 21,22,22), it is possible to prevent the draw ratio of the biaxial stretch blow molding of the bottom corner or the side corner of the inner blow molding container (20) from becoming more than 4.5 times. As a result, it is possible to provide a blow-molded composite container in which there is no possibility that the inner blow-molded container (20) will rupture and leak, and in which the amount of plastic material can be reduced.

Further, in the method for producing a blow-molded composite container of the present invention, a shape-maintaining cylinder made of paper is previously prepared in a blow-molding die having side molds (30, 30) and bottom mold (40). (Ten)
Is fitted and fixed to the void mold members (41, 41, 42, 42) provided in the bottom die (40), and is integrally biaxially stretch blow molded. Blow Molded Container (2
At the bottom corners or side corners of (0), the outer shape retaining cylinder (10)
The curved surface part (21,21,22,22) that becomes a gap between and is the curved surface (2,21,22,22) of the ring-shaped or triangular prism shaped mold member (41,41,42,42).
1,21,22,22) can be stably provided.

[Brief description of drawings]

FIG. 1 (A) is a perspective view of a blow-molded composite container according to an embodiment of the present invention, and FIG. 1 (B) is a shape-retaining member made of paper in the blow-molded composite container of the embodiment. Cylindrical body (10)
It is a top view of the blank of FIG.

FIG. 2 shows the blow-molded composite container shown in FIG.
It is sectional drawing (A) of XX plane, sectional drawing (B) of YY plane, and sectional view (C) of ZZ plane.

FIG. 3 shows the blow-molded composite container shown in FIG.
It is sectional drawing (A) of the blow molding die corresponding to the XX cross section, and sectional drawing (B) of the blow molding die corresponding to the YY cross section.

FIG. 4 is a cross-sectional view of a conventional blow-molded composite container.

[Explanation of symbols]

 10 ... Shape-retaining cylinder 11 ... Side plate group 12, 14 ... Adhesive strip 13 ... Side shoulder plate group 20 ... Blow molding container 21, 22 ... Curved part, curved surface 23 ... Pouring port 30 ... Side mold 40 ... Bottom mold 41 , 42 ... void Mold member 51 ... bottomed box body 52 ... cylindrical body a, b ... gap

Claims (4)

[Claims] 1. A blow-molding composite container in which a shape-retaining cylinder (10) made of paper is previously inserted into a blow-molding die and integrally biaxially stretch-blow-molded into an inner blow-molding container (20).
A blow-molded composite container, characterized in that curved surface portions (21, 21) which form a gap between the outer shape-retaining tubular body (10) are provided at corners of the bottom surface of the blow-molded composite container. 2. The side surface of the inner blow-molded container (20) in the case where the paper shape-holding cylinder (10) is a rectangular tube-shaped shape-holding cylinder (10). The blow-molded composite container according to claim 1, characterized in that curved portions (22, 22) that form a gap between the outer shape-retaining cylinder (10) are provided at the corners. 3. The void portion is provided so that the stretch ratio of the inner blow-molded container (20) is within 4.5 times in all portions. The blow-molded composite container described in. 4. A shape-retaining cylinder (10) made of paper is previously provided on the bottom die (40) in a blow molding die having a side die (30, 30) and a bottom die (40). A method for producing a blow-molded composite container, characterized in that the cavity mold member (41, 41, 42, 42) is fitted and fixed and inserted, and integrally biaxially stretch blow-molded.