JPH0427773Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a composite container containing paper, metal, and synthetic resin, which has particularly excellent preservability and fragrance retention of the contents. The present invention relates to a container suitable for storing foods, medicines, agricultural products, etc., in which a laminated sheet blank made of paper and synthetic resin is joined to a frame made of thermoplastic resin.

<Prior art> Conventionally, composite containers and containers have been manufactured in which a laminated sheet blank made of paper and synthetic resin is mounted in a mold, a gap is provided between the edges of the blank to form a framework, and thermoplastic resin is injected into the gap. The method for producing it is shown in Japanese Patent Publication No. 49-2302, Japanese Patent Publication No. 7867-1987, Japanese Patent Publication No. 8574-1973, etc.

As shown in Figure 9, the container body 1 is formed using aluminum foil or a laminated sheet blank made by laminating gas/liquid barrier resin, paper, and thermoplastic resin. However, as shown in Fig. 10, since a resin such as polyethylene or polypropylene is used as the frame 3 of the blank edge joint 2, the aroma components of the contents are absorbed by the frame 3. This has disadvantages in that water and water dissipate and oxygen enters the container, causing the contents to rot and go rancid, reducing the long-term shelf life of the contents, and impairing the commercial value of the contents. It is also possible to use gas/liquid barrier resin for the frame 3, but polyamide, polyvinyl chloride, polyester, ethylene/vinyl alcohol copolymer, etc. lack sealing suitability and will not thermally weld to the laminated sheet blank. Cannot be used as frame resin. In addition, these gas/liquid barrier resins lack moisture resistance, and their gas barrier properties and mechanical properties are highly dependent on humidity, and moisture absorption deteriorates these properties, so they are not suitable for containers that store contents for long periods of time. It wasn't suitable.

<Means for solving the problems> The present invention provides a composite container with excellent content preservation properties that solves the problems of the conventional technology as described above. An inner wall and a frame are provided on the inside of the side wall of the container body, and the frame is made of a laminate whose thickness direction includes at least a gas/liquid barrier resin and an adhesive polyolefin resin. It has a structure in which it is thermally welded.

Hereinafter, a detailed description will be given based on embodiments shown in the drawings.

<Example> First, as shown in FIGS. 1 to 3, the container of the present invention is made of a paperboard in which side plates 5, 6, 7, and 8 are connected to each other via fold lines around a substantially rectangular bottom plate 4. At least a gas/liquid barrier resin is provided in the gap 11 between the end edges 10, 10 of each side plate and inside each of the side plates 5, 6, 7, 8 of the blank having a thermoadhesive resin layer on the surface thereof. Frame 12 and inner wall 1 made of a laminate containing adhesive polyolefin resin
3, and the end edges of each side plate are connected to each other by resin constituting the frame 12.
Next, to explain an example of the manufacturing method, first, a ruled line is added to the laminated sheet blank b punched out using a die as shown in FIG.
The laminated sheet blank 2 is installed in the female mold shown in the figure to form a container body 9, and the end edge 1 of the container body 9 is
A male mold 15 and the female mold 1 are provided with a gap between them for forming an inner wall 13 inside the thermoplastic resin frame 12 and the side plates 5, 6, 7, 8 of the container body 9.
4, the injection unit A plasticizes and injects the first resin 16 that forms the inner and outer layers of the frame 12 and the inner wall 13, and the second resin 17 that forms the intermediate layer of the frame 12 and the inner wall 13. The injection unit B for plasticizing and injecting is connected to one die nozzle 18,
For example, as shown in FIG. 7, concentric tubular resin flow channels are provided in the die nozzle 18 so that the first resin 16 and the second resin 17 are laminated in a concentric tubular shape, and the screw or plunger of each injection unit is 19,
20 are advanced almost simultaneously to remove the frame 12 and the inner wall 1.
3, a laminated resin made of the first resin and the second resin is injected into the gap to form the frame 12 and the inner wall 13, at least one layer of which has a gas/liquid barrier resin layer in the thickness direction. Then, a container having a structure in which the simultaneously laminated blanks container body is heat-sealed is obtained.

In the above manufacturing method, the resins of each layer are injected in a laminated state, but as shown in FIG. Then, as shown in FIG. It is also possible to fuse them.

In addition, in order to pour laminated resin into narrow gaps,
It is necessary to be very careful about fluidity, and in particular, it is necessary that the positions of each frame be symmetrical and equidistant from the gate. If this condition is not met, there will be places where the laminated structure will not be formed, and the resin will flow in some parts of the framework other than the specified joint edges, forming burrs and protruding, which will seriously impair the appearance.

Here, it is preferable to use an adhesive polyolefin resin as the first resin 16 and a gas/liquid barrier resin layer as the second resin 17. May be used. Furthermore, the first resin,
There may be three or more layers, such as a second resin, a third resin, and so on. The reason for using adhesive polyolefin here is that gas/liquid barrier resins do not adhere to general polyolefin resins at all, so polyolefin resins are made by adding polar groups to the polyolefin resins so that they will adhere to gas/liquid barrier resins. It is. An appropriate amount of a general polyolefin resin may be mixed with the adhesive polyolefin resin.

Next, as a gas/liquid barrier resin, the thickness is 30μ.
~1000μ is appropriate, preferably 50μ to 500μ, and the resin is polyamide (6 nylon,
66 nylon, 6-66 copolymerized nylon, 12 nylon, etc.), polyvinyl alcohol, ethylene vinyl alcohol copolymer, polyvinylidene chloride, polyvinyl chloride, polyester (polyethylene terephthalate, polybutylene terephthalate),
Acrylic resin (acrylonitrile-styrene-
methacrylate copolymers, etc.) can be used.

Here, as the adhesive polyolefin resin, unsaturated carboxylic acid graft polymerization modified polyolefin (maleic acid, phthalic acid, ferric acid, itaconic acid,
Modified polyolefin (modified polyolefin in which monomers such as maleic anhydride, itaconic anhydride, maleic acid monoethyl ester, fumaric acid monomethyl ester, itaconic acid mononormal butyl ester are grafted onto polyolefin), acrylic acid graft polymerized polyethylene, ionomer, ethylene vinyl acetate Copolymers, ethylene-ethyl acrylate copolymers, ethylene-acrylic acid copolymers, etc. can be used, and polyethylene and polypropylene can be used as general polyolefin resins.

<Effects of the Invention> The present invention has the above-mentioned configuration, and the container body uses a laminated sheet or film made of paper and thermoplastic resin, and at least one layer of the frame and inner wall of the blank edge joint is made of gas-containing material. Because it has a laminated structure made of liquid-blocking resin, it does not suffer from loss of water dispersion or spoilage of the contents due to the intrusion of oxygen gas, which were disadvantages of polyethylene, polypropylene, polystyrene, etc. used for the framework of the edge joints of blanks. There is no reduction in product value due to rancidity, loss of aroma components, etc., and long-term storage is possible. In addition, conventionally, when gas/liquid barrier resins such as polyamide, polyvinyl chloride, polyester, etc. are used for the frame, heat fusion properties with the laminated sheet and film of the container body, or heat fusion with the lid material film that seals the top of the container, have been reported. Gas/liquid barrier resins are not suitable for containers that store contents for long periods of time due to lack of adhesion properties, lack of moisture proofing properties, content moisture and thickening, and moisture absorption. However, with the present invention, the drawbacks of the single resin are compensated for by creating a laminated framework in which a moisture-proof resin such as polyethylene or polypropylene and the gas/liquid barrier resin described above are laminated. A container having both fusibility and gas/liquid barrier properties can be obtained.

Further, since an inner wall made of a relatively thick molded resin is provided on the inside of the side plate of the container body, the strength is much superior to that in the case where a layer of resin is simply provided.

Furthermore, since the blanks are not laminated with aluminum foil, gas barrier resin, etc. in advance, they do not curl during storage, transportation, supply, etc., and the framework and inner walls made of the blanks and molded resin are formed simultaneously. Since they are bonded together, they are tightly adhered to each other, and the labels do not peel off like in conventional labeled containers.

In addition, the container of this invention does not generate bacteria.
Hygienic.

[Brief explanation of the drawing]

1 to 8 show an embodiment of the present invention, in which FIG. 1 is a perspective view, FIG. 2 is a plan view of a blank constituting the container body, and FIG. 3 is a perspective view of the container body. FIG. 4 is a longitudinal cross-sectional view of part a in FIG. 1;
Figure 5 is a cross-sectional view of the same, Figure 6 is A-A of Figure 1.
7 is an explanatory diagram showing an example of the apparatus for manufacturing the present invention; FIGS. 8A and 8B are explanatory diagrams showing the manufacturing process of the present invention; FIGS. 9 and 10 are Regarding the prior art, FIG. 9 is a perspective view, FIG. 10A is a vertical cross-sectional view of section b in FIG. 9, and FIG. 10B is a cross-sectional view of the same. 1, 9...Container body, 2...Edge joint, 3,
13...Frame, 4...Bottom plate, 5, 6, 7, 8...
Side plate, 10... Edge, 11... Gap, 13...
Inner wall, 14... female mold, 15... male mold, 16... first resin, 17... second resin, 18... die nozzle, 19, 20... plunger, 21... cavity.

Claims (1)

[Scope of utility model registration request] Each gap between adjacent side plates and the inside of each side plate among the plurality of side plates of a paper container body having a thermal adhesive resin layer on the surface of a paperboard made of a plurality of side plates arranged around a bottom plate. The inner wall and framework are formed by heat-sealing a laminated resin layer containing at least a gas/liquid barrier resin and an adhesive polyolefin resin, and are integrally connected to the container body, providing excellent content protection. Composite container.