JPS61209116A - Manufacture of composite vessel, opening of which is prevented from deforming - Google Patents

Abstract

PURPOSE:To prevent the opening of a composite vessel from deforming by a method wherein a plug with a perfect circular cross section is insertedly fitted to the opening of the composite vessel, which is obtained by integrally joining a flexible label member on a skeletal member, quickly after the vessel is taken out of a molding tool. CONSTITUTION:Firstly, a label member 1 prepared out of a flexible thin layer body is inserted in and fixed to an injection mold. At that time, the label member is assembled so that its two sheets of side wall labels constitute the side wall of a right cylindrical vessel after being bent at hinge parts 4. Secondly, molten thermoplastic resin is poured in the remaining cavity for molding a skeletal member of the mold by injection molding method so as to mold the skeletal member consisting of an upper edge opening rib 6, a lower edge bottom rib 7 and side wall ribs 8 and at the same time to join integral with the assembled label member in order to obtain a composite vessel. Finally, the composite vessel is removed from the mold and, after that, a plug 9 is quickly insertedly fitted to the opening of the composite vessel. The above-mentioned state is held until just before the usage of the composite vessel.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for manufacturing a composite container in which deformation of the opening is prevented. More specifically, the present invention relates to a method for preventing the opening from deforming after a composite container having a perfectly circular opening is removed from a molding die.

``Prior Art'' Conventionally, as a method for manufacturing containers, it is known that the entire container is integrally formed with synthetic resin using injection molding, but generally speaking, when trying to reduce the thickness of the container wall, it is necessary to change the material. It was difficult to inject into the mold, and therefore there was a limit to how thin it could be.

In order to eliminate such drawbacks, a composite container is developed in which a part of the container, for example, the side wall, or the bottom wall and the side wall, is made of a flexible label material, and the aggregate that joins these parts is made of thermoplastic resin. was proposed and put into practical use (Japanese Unexamined Patent Publication No. 46-6
No. 640, JP-A-50-47785).

Such composite containers are produced by inserting and fixing a label material cut into a desired shape into a part of the cavity of an injection mold, then closing the mold, and then injecting molten resin into the remaining part of the cavity. Then, a spliced aggregate composed of the upper edge opening lip, the side wall lip, and the lower edge bottom rib (and in some cases, the bottom wall portion) is formed, and at the same time, it is integrally joined with the label material to form a composite container. At this time, the mutually adjacent side edges of the side wall label of the label material are joined by the side wall ribs, and the opening is fixed to the upper edge of the side wall label by the upper edge opening rib, and is fixed and strengthened.

It is said that if the composite container obtained in this way is formed into a perfect circular shape at the container opening, it will gradually deform into an elliptical shape over time after being removed from the mold. phenomenon was observed. The following reasons can be considered as reasons why such a phenomenon occurs.

(1) Although the flexible label material is originally flat, it is transformed into a three-dimensional shape with a forced curved surface in the mold and fixed with aggregate, which causes the label material to rebound. A force acts on the upper edge aperture rib, causing cold flow to occur in the resin forming the upper edge aperture rib, causing it to gradually deform.

(2) After the side wall ribs that join the mutually adjacent both side edges of the side wall label of the label material shrink in the height direction of the container (the length direction of the side wall label), the upper edge opening rib is It is stretched downward at the joint with the lip, which deforms the opening into an oval shape.

Such a drawback is particularly noticeable when the thermoplastic resin used as the aggregate is made of polyethylene or polypropylene, which has a lath transfer temperature lower than room temperature.

If the container opening deforms into an elliptical shape like this,
When the opening of the container is covered with a lid after an article has been stored in the container, there is a drawback that the lid does not fit properly. For example, when using a drop-in lid or a cover lid, these lids are made in advance in a perfect circular shape, so the shape of the container opening does not match the shape of the lid, and it is impossible to insert and fit smoothly.

Furthermore, when wrapping the metal lid around the opening, the shape of the perfectly circular metal lid and the opening of the container do not match, making it impossible to wrap the entire container uniformly. Furthermore, when heat-sealing or ultrasonically sealing a flat, perfectly circular lid to the container opening, the shapes of the lid and the container opening do not match, so both the lid and the container opening are sealed evenly. Since it does not end with heat fusion, there may be some areas that cannot be bonded.

As described above, in conventional composite containers, the shape of the container opening and the container lid material do not match, so when filling soft drinks etc. into composite containers, it is difficult to use the filling line for conventional metal cans. However, when using the method of overlapping the lid material over the opening of the container and gluing it, it was not possible to obtain a sealed container with an excellent appearance.

"Problems to be solved by the present invention" The present invention solves the above-mentioned drawbacks, and the shape is
The present invention provides a method for manufacturing a composite container that does not deform over time.

"Means for Solving the Problem" The gist of the present invention is to fix and hold a visible label material that constitutes a part of a wall surface such as a side wall or a bottom wall of a container in a mold cavity; Molten thermoplastic resin is injected into the remaining part of the cavity to form the aggregate of the container, and at the same time, the flexible label material and the aggregate are integrally joined to form a composite container with a true H-shaped opening. , Immediately after taking out the composite container from the mold, insert and fit a plug having a perfect circular cross section into the opening of the composite container, and then maintain the state in which the plug is inserted and fitted into the container opening. A method of manufacturing a composite container in which deformation of an opening is prevented is provided.

The present invention will be explained in detail below based on the drawings.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

Fig. 1 is a diagram showing an example of a state in which the present invention is implemented, and shows the positional relationship between the plug and the composite container. 3 is a developed view of an example of the visible label material constituting the composite container according to the present invention, and FIG. 4 is a perspective view of a composite container formed using the label material shown in FIG. 3. , FIG. 5 is a diagram showing another example of the state in which the present invention is implemented, and is a longitudinal cross-sectional view showing the positional relationship between another example of the plug and the composite container. FIG. 7 and 8 are respectively developed views of other examples of flexible label material, and FIG. 9 is a cross-sectional view of the section ■-■, and FIG. 9 is a cross-sectional view of another example of the flexible label material. FIG. 10 is a perspective view of a composite container, FIG. 10 is a front view of an example of a plug plate used in carrying out the present invention, and FIG.
Fig. 12 is a plan view of an example of a container equipped with a plug, and Fig. 13 is a longitudinal cross-sectional view taken along line IV-■ in Fig. #S12. .

In the figure, 1 is a visible label material, 2 is a side wall label, and 3 is a visible label material.
is the bottom wall label, 4 is the hinge part, 5 is the cut line, 6.6
1 are upper edge opening ribs, 7°71 are lower edge bottom lips, 8.81 are side wall lips, 9.91, 92.
93 is a plug, 10, 101 and 102 are thin plates, and 11 is a container.

When manufacturing a composite container by the method of the present invention, a label material that forms part of the wall surface such as the side wall and bottom wall of the container is used. An example of the label material is shown in a developed view in FIG. The label material illustrated in FIG. 3 is used when manufacturing a composite container having a right cylindrical body and a perfectly circular opening. The label material 1 consists of a circular bottom wall label 3 and two side wall labels 2.
are continuous by the hinge part 4.

The bottom wall label 3 constitutes the bottom wall of the container, and the side wall label 2 constitutes the side wall (body) of the container. It is recommended that the two side wall labels be rectangular and placed in symmetrical positions with the bottom wall label in between. Good.

The label material is preferably prepared from a flexible laminate.

Examples of flexible thin laminates include thermoplastic resin sheets (including foamed sheets and laminated sheets), laminates of metal foil and thermoplastic resin sheets, and laminates of paper and thermoplastic resin (two-layer to multi-layer). ), laminates of paper and thermoplastic resin sheets with metal foil (including multilayers of three or more layers), and products with the same effect as these.

The label material 1 is inserted and fixed into an injection mold. At this time, the label material is bent at the hinge part 4, and the two side wall labels 2 are assembled to form the side wall of the right cylindrical container.Then, the remaining aggregate forming cavity of the mold is filled with molten thermoplastic resin. is injected by an injection molding method to form an aggregate composed of the upper edge opening lip 6, the lower edge bottom lip 7, and the side wall lip 8. At the same time, by integrally joining with the assembled label material, the fourth A composite container as shown in perspective view is obtained.

The upper edge opening lip 6 reinforces the container opening, and the lower edge bottom lip 7
The lip 8 serves to join the peripheral edge of the bottom wall label and the lower edge of the side wall label, thereby sealing and reinforcing the peripheral edge of the bottom wall inside the container.The side wall lip 8 joins the mutually adjacent opposite side edges of the side wall label.

Preferably, the aggregate is formed inside the label material.

When the aggregate is formed inside the label material, the wood end (cut end) of the label material is not exposed on the inside of the container, which prevents the filling in the container, especially liquid, from penetrating into the label material from the wood end. is possible and preferred.

When following the method of the present invention, the composite container thus obtained is removed from the mold, and the plug 9 is immediately inserted and fitted into the opening of the composite container to form the state shown in FIG. This state is maintained until the composite container is ready for use. The plug 9 shown in FIG. 1 is prepared by processing a thin plate 10. The shape of this plug is preferably a right cylindrical shape when used for a right cylindrical composite container, but it is preferable to make the tip end thinner in order to facilitate attachment and detachment of the plug. Also, the shape of the cross section (second
(see figure) must be perfectly circular.

The tip of the plug should be rounded so that it can be easily inserted into the opening of the composite container and will not damage the container. The diameter of the plug is preferably equal to the inner diameter of the opening so that it fits snugly into the opening of the container.The height of the plug is preferably 172 mm or less of the height of the container.

It is preferable to form multiple plugs into one piece on a thin plate.The plugs are inserted into the container opening of the composite container and maintained in this inserted state to prevent deformation of the container opening over time. It serves the function of preventing The thin plate used for plug preparation is not particularly limited as long as it exhibits sufficient performance to prevent deformation of the container opening after being made into a plug.

For example, thin metal plates such as aluminum and stainless steel, styrene resins, vinyl chloride resins, thermoplastic resins such as polycarbonate and polyester, phenol, melamine,
Examples include thermosetting resins such as epoxy and unsaturated polyester, and materials made by reinforcing these resins with reinforcing materials such as glass fiber. In order to form a large number of plugs on these thin plates, methods known per se such as cold forming, compression molding, thermoforming, differential pressure forming of thin plates, injection molding of these materials, and spray molding are used. Bye.

The method of the present invention can also be applied to an inverted truncated cone-shaped composite container obtained using a label material as shown in developed views in FIGS. 7 and 8, and as shown in a perspective view in FIG. I can do it. tJfJs is a vertical cross-sectional side view showing the relationship between the opening of the composite container and the plug 91 in a state where the plug 91 is inserted and fitted into the opening of the composite container having an inverted truncated conical shape. The label material shown in FIG. 7 constitutes only the side wall of the container, and the aggregate is composed of the upper edge opening lip, the side wall lip, the lower edge bottom lip, and the bottom wall.

In such an inverted truncated conical composite container, the plug 91 used must have a truncated conical shape with an inclination of the same degree as that of the composite container. Furthermore, the diameter of the truncated cone at any height must be equal to the inner diameter of the opening of the composite container.

A frustoconical plug can also be used in a right cylindrical composite container.

As shown in FIGS. 10 and 11, such a plug is made of, for example, a thin thermoplastic resin plate 102,
It is preferable to form a structure such as a plug plate in which a plurality of plugs 92 are integrally molded by differential pressure molding. This kind of plug plate is lightweight and compact because the inside of the plug is hollow, so it is possible to stack the plug in a composite container and store it in multiple layers in a cardboard box, etc. This makes it convenient for storing the composite container until it is ready for use or for transporting it to a remote location. Such a plug plate can also be made into a thin-walled molded product by injection molding of other synthetic resins. If the plug is made of metal, the desired plug plate can be obtained by integrally forming a large number of hollow plugs on a thin metal body by ordinary compression molding, cold-opening molding, or the like.

Other examples of plugs that may be used in practicing the invention are shown in FIGS. 12 and 13. What is shown in these figures is the bottom of a container 11 that stores a large number of composite containers.
This is a structure in which a large number of plugs 93 are integrally molded. Such a container with a plug on the bottom can store a composite container with a plug fitted into the composite container, and can be stacked in multiple tiers, making it easy to store items in the composite container. Until just before it is used for storage,
It is more convenient to store or transport to remote locations. Such containers can be obtained by injection molding methods.

In the present invention, thermoplastic resins used for forming aggregates include olefin resins such as polyethylene, polypropylene, and 17-methylpentene, styrene resins such as polystyrene, rubber-reinforced polystyrene, and ABS resins, polyvinyl chloride, and vinyl chloride. vinyl chloride resins such as copolymers and graft polymers, acrylic resins such as polymethyl methacrylate, polyamides such as nylon 6 and nylon 66, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, ethylene- Examples include saponified vinyl acetate copolymers and other thermoplastic resins commonly used in injection molding.

These thermoplastic resins may contain inorganic fillers, colorants, and the like.

"Effects of the Invention" According to the method of the present invention, a composite container whose opening part is not deformed or whose deformation amount is small can be obtained. In addition, in the composite container obtained according to the method of the present invention, the shape of the opening does not change to an elliptical shape, or even if it deforms, the amount of deformation is small. Even if a lid is used, it can be smoothly fitted or adhered. Moreover, it is very convenient for storing and transporting composite containers, and its industrial utility value is extremely large.

"Example and Comparative Example" Using a flexible label material as shown in Figure 3,
Based on the method described in 4-134020, the fourth
A right cylindrical composite container as shown in the figure was manufactured. The flexible label materials used at this time were: PP (20μ) 7 paper (100μ) / Aluminum foil (9μ) /
A thin layer consisting of four layers of PP (40μ) (PP...polypropylene, the thickness of each layer is in parentheses) was used, and polypropylene was used as the aggregate. The obtained composite container had an inner diameter of 53 m and a height of 1,301 m.

On the other hand, a biaxially stretched polystyrene sheet (manufactured by Mitsubishi Monsando Co., Ltd., trade name: Santo Clear) with a thickness of 0.7 mm was used as a raw material, and was used as a plug as shown in Fig. 10 by an air pressure forming method. A plug plate (molded product) was manufactured. The outer diameter of the plug was 53 mm, and the height from the seat surface was 2 (1+ m).

Immediately after the molded composite container was removed from the mold, the opening of the composite container was inserted and fitted into each plug of the plug plate. The plug plate in which all the plugs were inserted and fitted with the composite container openings was stored in a cardboard box and then left at room temperature. Thereafter, the difference between the major axis and the minor axis of the openings of these composite containers was measured using a vernier caliper over time. The smaller the difference, the smaller the deformation of the opening of the composite container, which means that it is closer to a perfect circle. The measurement results are shown in Table 1. For comparison, similar measurements were also performed on a composite container that was left at room temperature without fitting the plug after molding. The results are also shown in Table 1.

Table 1 (Unit - 1) As is clear from Table 1, the opening of a composite container with a plug inserted and fitted into the opening has a much more oval shape than one without a plug inserted and fitted. small. Generally, when using a container with a perfectly circular opening, the allowable range for the difference between the major axis and the minor axis of the container opening is said to be 2III or less, but in the case of the composite container of the comparative example, one day after molding, In contrast, in the case of composite containers made by the method of the present invention, even after one month has passed after molding,
This is within the permissible range.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a state in which the present invention is implemented, and FIG. 2 is a longitudinal cross-sectional view showing the relationship between the plug and the composite container, and FIG. end view,
31st! I is an arm view of an example of a flexible label material constituting a composite container according to the present invention, FIG. #4 is a perspective view of a composite container formed using the label material of FIG. 3, and FIG. FIG. 6 is a diagram showing another example of the state in which the present invention is implemented, and is a longitudinal cross-sectional view showing the positional relationship between another example of the plug and the composite container. The top view, FIG. 7, and FIG. 8 are developed views of other examples of flexible label materials, respectively.
tIS 9 is a perspective view of a composite container molded using the label material shown in FIG. Fig. 10 is a vertical sectional view taken along the line ■-■ in Fig. 10, Fig. 12 is a plan view of an example of a container equipped with a plug, and Fig. 1@13 is a longitudinal sectional view taken along the line IV-IV in Fig. 12. It is. In the figure, 1 is a flexible label material, 2 is a side wall label, and 3 is a flexible label material.
is the bottom wall label, 4 is the hinge part, 5 is the cut line, 6.6
1 is the upper edge opening lip, and 7.71 is the lower At.
Bottom ribs, 8, 81 are side wall ribs, 9, 91, 92, respectively.
．． 93 is a plug, 101101.102 is a thin plate, and 11 is a container. Applicant Mitsubishi Monsanto Chemical Co., Ltd. Agent Patent Attorney Hase - (1 idiot) Excuse 1 Figure/l/ Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 Figure 6 Figure 6 Excuse cl Cause 10 Diagram 2: Frag/a2: Hisao Book 11 Diagram A2: IF#

Claims (3)

[Claims] (1) The flexible label material that forms part of the side walls, bottom wall, etc. of the container is fixed and held in the cavity of the mold, and molten thermoplastic resin is injected into the remaining part of the cavity to form the container. At the same time as forming the aggregate, after removing the composite container with a perfectly circular opening obtained by integrally joining the flexible label material and the aggregate from the mold, immediately insert the composite container into the opening of the composite container. A method for manufacturing a composite container which prevents deformation of an opening, characterized by inserting and fitting a plug having a perfect circular cross section, and then maintaining a state in which the plug is inserted and fitted into the opening of the container. (2) Manufacture of a composite container that prevents deformation of the opening as set forth in claim (1), characterized in that a plurality of plugs are integrally formed on a thin plate as plugs. Method. (3) Preventing deformation as set forth in claim (1), characterized in that a plurality of plugs having a hollow structure integrally formed at the bottom of the portable composite container are used as plugs. A method for manufacturing a composite container.