JPH10296788A - Production of composite container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a composite container having good sealing properties when a lid member is placed in position. SOLUTION: A method for producing a composite container comprising the steps of placing a container main body 210 at a predetermined position inside an injection molding mold in which a bottom portion is jointed to a body portion made of a liminated material having a paper layer as a main layer and a thermoplastic resin layer provided on at least the inner side of the container at an inside lower portion thereof, and injecting fused thermoplastic resin into a cavity 130 so as at least to provide an open circumferential edge portion to fit in a lid member, wherein a gate 101 is disposed at a part of the injection molding mold excluding a fitting surface to fit in the lid member on the open circumferential edge portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cup-shaped or tray-shaped container body made of a laminated material having a paper layer as a main layer. The present invention relates to a method of manufacturing a composite container in which an annular reinforcing portion is provided at a joint between a body portion and a bottom portion by injection-molding a thermoplastic resin.

[0002]

2. Description of the Related Art Conventionally, as a container for yogurt, fruit juice drink, sake, jam, granular confectionery, etc., a fan-shaped trunk blank made by punching a laminated material having a paper layer as a main layer is formed into a cylinder to form a trunk. A cup-shaped paper container in which a circular bottom blank formed by stamping a laminated material is combined below the body and the lower periphery of the body and the periphery of the bottom are tightly wound in a heated state has been used. However, in this cup-shaped paper container, it is difficult to obtain a sufficient container sealing property due to the step of the bonding portion of the body when the lid is attached to the opening at the upper end of the body.

Therefore, in order to improve the sealing property of the container with the lid material, for example, Japanese Patent Application Laid-Open No. 8-207924 discloses a method in which a cup-shaped paper container is loaded into an injection mold and a thermoplastic resin is injected. There has been proposed a composite container method in which an opening edge is provided at an opening at the upper end of a body of a cup-shaped paper container.

[0004]

However, in the method described in Japanese Patent Application Laid-Open No. 8-207924, a gate is provided at a portion corresponding to the inner surface near the upper end of the container at the periphery of the opening. When attached to a container, there were cases where sufficient sealing of the container could not be obtained due to the remaining gate marks.

The present invention solves the above-mentioned conventional problems, and provides a method for producing a composite container having a sufficient hermeticity when the lid is attached.

[0006]

Means for Solving the Problems A first invention of the present invention is:
As shown in FIG. 1, a container main body (210) in which a paper layer is a main layer and a bottom portion is joined to a lower portion inside and below a body portion made of a laminated material having a thermoplastic resin layer provided on at least the inner surface side of the container is used for injection molding. The resin is charged at a predetermined position in the mold (100), and the molten thermoplastic resin is injected into the cavity (130) (the space between the female mold and the male mold). In the method for manufacturing a composite container provided with at least the opening peripheral portion (220) shown in FIG. 2 to be fitted to the lid material, the injection molding metal excluding the fitting surface of the opening peripheral portion (220) with the lid material. A method for manufacturing a composite container, characterized in that a gate (101) (gate for injecting a molten resin into a cavity) is disposed at a position of a mold.

Next, as shown in FIG. 1, the second invention of the present invention comprises a paper layer as a main layer and a thermoplastic resin layer provided on at least the inner surface side of the container. The container body (210) having the bottom joined to a predetermined position in the injection mold (100) is loaded into the cavity (1).
The molten thermoplastic resin is injected into the inside of the container 30, and as shown in FIG. 2, the opening peripheral portion (211) which fits the lid material into the opening (211) at the upper end of the body (212) of the container body (210). 22
0) and a method of manufacturing a composite container (200) in which a columnar protective portion (230) is provided in a vertical bonding portion inside a body portion, as shown in FIG. A gate (101) is arranged at one or more of the portions of the injection mold except for a fitting surface with the gate.

[0008] The third invention of the present invention is to provide a container body having a paper layer as a main layer and a bottom portion joined to a lower portion inside a body portion made of a laminated material having a thermoplastic resin layer provided on at least an inner surface side of the container. , Loaded into a predetermined position in the injection mold,
The molten thermoplastic resin is injected into the cavity, and as shown in FIG. 4, an opening peripheral portion (2) that fits with the lid material is inserted into the opening (211) at the upper end of the body (212) of the container body (210).
20), a column-shaped protective portion (230) is provided on a vertical bonding portion inside the body portion, and an annular reinforcing portion (240) is provided at a joint between the body portion and the bottom portion (214). 20
0) In the manufacturing method of 0), a gate is disposed at one or more of the injection molding die portions except for a fitting surface of the peripheral portion of the opening with the lid material, wherein a gate is disposed. Is the way.

[0009]

In the manufacturing method of the present invention, the gate of the injection molding die is disposed at a portion of the periphery of the opening other than the fitting surface with the lid member, and the upper end of the body of the manufactured composite container is provided. The fitting surface of the peripheral edge of the opening provided in the opening with the lid is smooth without any remaining gate marks, so that when the lid is mounted, the container is sufficiently sealed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a composite container according to the present invention comprises:
First, a paper layer as a main layer, punching a laminated material provided with a thermoplastic resin layer at least on the inner surface side of the container, for example, to produce a fan-shaped body blank and a circular bottom blank,
The trunk blank is rolled into a cylinder to form a trunk, and the bottom blank is combined below the trunk, and the lower periphery of the trunk and the periphery of the bottom are tightened in a heated state to integrate the trunk and the bottom. To produce a cup-shaped container body, and this container body (21
1) is loaded into a predetermined position of an injection mold (100) composed of a female mold (110) and a male mold (120) attached to an injection molding machine as shown in FIG. The molten thermoplastic resin is injected from the gate (101) into the inside (130), and at least the opening peripheral part (220) to be fitted with the lid material is provided in the opening (211) at the upper end of the body part (212) shown in FIG. Further, a columnar protective portion (230) connected to the opening peripheral portion (220) at the vertical bonding portion (213) inside the trunk portion (212) shown in FIG. 2 or FIG.
And the trunk (212) and bottom (214) shown in FIG.
An annular reinforcing portion (240) that is continuous with the columnar protective portion (230) is provided at the joint. The position of the gate provided in the injection molding die is one (for example, as shown in FIG. 1) or a plurality of positions in a portion other than the fitting surface of the peripheral portion of the opening with the lid material.

The shape of the composite container can be appropriately selected according to the purpose of the container, and may be cup-shaped or tray-shaped, or may have a vertical body as shown in FIG. Further, the shape of the upper end of the body portion of the container body provided with the opening peripheral portion may be an extended shape of the body portion shown in FIG. 2, a shape expanding outward as shown in FIG. 6A, or a shape shown in FIG. It may be curled.

Further, the thermoplastic resin formed by the opening peripheral portion, the columnar protective portion and the annular reinforcing portion on the cup body may be selected from those having thermal adhesiveness to the thermoplastic resin layer on the inner surface of the container body, depending on the purpose of the container. An appropriate resin can be selected and used.In general use, a general-purpose resin such as polyolefin is used.Especially, when the protection of the contents is considered, ethylene-vinyl alcohol copolymer, polyethylene terephthalate, Acrylonitrile and the like can be used.

The laminated material constituting the container body may be a barrier layer as an intermediate layer in consideration of the protection of the contents, such as a metal foil layer, an inorganic vapor-deposited film layer such as silicon oxide, or an ethylene-vinyl alcohol copolymer. Layers and the like can be used.

[0014]

EXAMPLE First, using a laminated material of a polyethylene layer (20 μm) / paperboard layer (basis weight 280 g / m ² ) / polyethylene (20 μm), the height was 88 mm, the outside diameter of the opening was 60 mm, and the bottom was A cup-shaped container body having an outer diameter of 60 mm was prepared, and then the container body was loaded into a female mold of an injection molding die attached to an injection molding machine, and after closing the mold, hot-melted polyethylene was passed through a gate. Inject into the cavity,
A cup-shaped composite container according to this example in which an opening peripheral portion, a columnar protective portion, and an annular reinforcing portion were formed in a container body was produced. In addition, as shown by the gate mark (221) of the composite container (200) in FIG. 7, one gate of the injection molding die is provided on the outer peripheral surface of the opening peripheral portion (220). The composite container produced had an outer diameter of 65.5 mm at the periphery of the opening, an inner diameter of 56.5 mm for fitting with the lid, and a height of 90 mm.

Next, a lid material (300) shown in FIG. 7 was produced by injection molding of polyethylene. This lid material is a top plate (3
10) an inner ring (320) vertically fitted to the inner peripheral surface of the opening of the container on the inner peripheral surface of the outer periphery,
The outer diameter of the top plate is 65.5 mm and the outer diameter of the inner ring is 5
The gate thickness was 6.4 mm, the average thickness was 1.1 mm, and the gate position was located at the center of the inner surface of the top plate. As shown in FIG. 7, a fitting groove groove (222) having an inner diameter of 56.8 mm with respect to the lid member (300) is provided at a position in the middle of the inner peripheral surface of the opening peripheral portion (220) of the container (200). The outer diameter of the inner ring (320) of the lid material corresponding to the fitting groove groove is 5 mm.
A 7.0 mm fitting convex ring (321) was provided.

Then, the composite container according to the present embodiment is filled with 20 ml of turpentine oil to which 3% by weight of the oil red reagent is added, and the above-mentioned lid is fitted thereto. Although the container was left upside down for a while, no leakage of the contents from the fitting portion between the container and the lid material could be confirmed.

[0017]

According to the composite container manufactured by the manufacturing method of the present invention, the fitting surface for fitting with the lid material at the periphery of the opening provided at the opening at the upper end of the body has no remaining gate marks and is smooth. Therefore, when the lid member is attached, the hermeticity of the container is sufficiently obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a state in a mold in which a container body is loaded in a method for manufacturing a composite container according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the composite container manufactured by the manufacturing method of the present invention shown in FIG.

FIG. 3 is a sectional view taken along line A-A ′ of FIG. 2;

FIG. 4 is a sectional view of a composite container manufactured by a method for manufacturing a composite container according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view of a composite container manufactured by a method for manufacturing a composite container according to another embodiment of the present invention.

FIGS. 6A and 6B are cross-sectional views showing another example of the shape of the opening of the composite container.

FIG. 7 is a partial cross-sectional view showing a fitted state of the composite container of the embodiment with a lid member.

[Explanation of symbols]

 100: Mold for injection molding 101: Gate 110: Female mold 120: Male mold 130: Cavity 200: Composite container 210: Container body 211: Opening 212: Body 213: Pasting Fitting portion 214 Bottom 220 Opening edge 221 Gate mark 222 Fitting groove ring 230 Column protecting portion 240 Ring reinforcing portion 300 Lid 310 Top plate 320 Inner ring 321 …… Mating convex ring

Claims (3)

[Claims] A container body having a paper layer as a main layer and a bottom portion joined to a lower portion inside a body portion made of a laminated material having a thermoplastic resin layer provided at least on the inner surface side of the container, is provided in a predetermined shape in an injection mold. In the method of manufacturing a composite container, the molten thermoplastic resin is injected into the cavity, and the opening at the upper end of the body of the container main body is provided with at least an opening peripheral portion to be fitted with a lid material. A method for manufacturing a composite container, wherein a gate is arranged at a portion of the injection molding die except for a surface of the opening peripheral portion which is fitted with a lid member. 2. A container body having a paper layer as a main layer and a bottom joined to a lower inside of a body made of a laminated material having a thermoplastic resin layer provided on at least an inner surface side of the container, is provided in a predetermined position in an injection mold. The molten thermoplastic resin is injected into the cavity, an opening peripheral portion is provided at the opening at the upper end of the body of the container body to fit the lid material, and a vertical adhesive inside the body is provided. In the method of manufacturing a composite container provided with a columnar protective portion at a joining portion, a gate is disposed at one or more portions of the injection molding die except for a fitting surface of the opening peripheral portion with a cover material. A method for producing a composite container, comprising: 3. A container body having a paper layer as a main layer and a bottom joined to a lower inside of a body made of a laminated material having a thermoplastic resin layer provided at least on the inner surface side of the container. , Melted thermoplastic resin is injected into the cavity, an opening peripheral portion is provided at the opening at the upper end of the body of the container body to fit the lid material, and the inside of the body is vertically bonded. In the method for manufacturing a composite container having a columnar protective portion provided on a portion and an annular reinforcing portion provided at a joint between a body portion and a bottom portion, the injection molding metal excluding a fitting surface of the opening peripheral portion with a lid member. A method for producing a composite container, wherein a gate is disposed at one or a plurality of locations of a mold.