JPH074164Y2 - Multi-layer container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a multi-layer container, and more particularly to a multi-layer container having a uniform thickness and excellent in rigidity, gas barrier property and transparency.

[Problems to be solved by conventional techniques and devices]

BACKGROUND ART Desserts such as jelly and pudding and packaging containers such as jam are conventionally manufactured by a drawing method. As a rigid resin sheet having a gas barrier property, a container formed by the drawing method is usually a laminated sheet of a gas barrier resin and another thermoplastic resin, which is softened by heating and then drawn into a mold to be molded. Therefore, there is a problem that the thickness of the obtained product becomes non-uniform, a thin portion locally occurs, the rigidity is lowered as a whole, and the appearance of the product becomes poor.

In order to prevent a decrease in rigidity due to local thinning due to molding, some containers use thick sheets,
Since the sheet cannot be rolled up, there are problems that handling is extremely inconvenient, productivity is low, and product cost is high.

In addition, a laminated sheet of polypropylene having high heat resistance and a resin having gas barrier properties is often used for molding a container that contains contents that need to be heat-filled, boiled, heat treated such as retort, etc. The inside becomes decompressed,
There is a problem that the thin part is dented.

On the other hand, the container formed by the injection molding method is excellent in transparency and rigidity, but there is a problem that it is difficult to obtain a gas barrier property.

Therefore, an injection-molded container having a gas barrier layer as an intermediate layer has been proposed, but when manufacturing such a multi-layer container by injection molding, it is necessary to use a molding device having a very special structure. However, this is not suitable for containers that require low cost.

As described above, none of the conventional containers described above satisfies the conditions that the thickness is uniform, the rigidity is excellent, the gas barrier property is provided, and the cost is low.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems and to provide an inexpensive multilayer container having a uniform wall thickness, excellent rigidity and transparency, and gas barrier properties.

[Means for Solving the Problems]

As a result of earnest research in view of the above problems, the present inventor has found that a resin sheet having a gas barrier property is molded into a container shape as a container inner layer, and an outer layer is integrally molded with the outer layer by injection molding to provide a rigid body. In order to improve transparency and gas barrier properties, a laminated sheet composed of a polyethylene terephthalate layer, an ethylene-vinyl acetate copolymer layer and a transparent resin layer is used as an inner layer from the inner surface side, and an upper layer is formed as an outer layer. The inventors discovered that it would suffice to injection-mold the same transparent resin, and conceived the present invention.

That is, the multi-layer container of the present invention comprises an inner layer made of a resin sheet having a gas barrier property and an outer layer integrally formed by injection molding on the outer surface side of the inner layer. A polyethylene terephthalate layer, an ethylene-vinyl acetate copolymer layer and a transparent resin layer, and the outer layer is made of the transparent resin.

The multi-layer container of the present invention is further heat-sealed from the upper side with a gas barrier inner lid made of a laminated sheet consisting of a crystalline polypropylene layer, an ethylene-vinyl acetate copolymer layer, and a sealant layer mainly composed of polyethylene. By providing an outer lid made of polypropylene that has an annular projection on the inner surface that can be detachably engaged with the flange portion of the upper end of the container by snap fit,
It provides sealing and rigidity as a packaging container, and protects the contents after opening, which is convenient for transportation and has a high display effect.
It is a product with excellent storability and usability.

[Action]

Since polyethylene terephthalate used for a laminated sheet having gas barrier properties has good chemical resistance, oil resistance, etc., it has good storage stability for contents such as beverages and foods. Moreover,
Since there is no odor, no odor will be transferred to the contents.
By using such polyethylene terephthalate in the layer forming the innermost surface of the container, the safety of the contents such as food is improved.

The ethylene-vinyl acetate copolymer has good elongation and gas barrier properties. The outer side of the inner layer and the outer layer to be injection-molded are made of the same transparent resin, and polystyrene and polypropylene are preferable as the transparent resin. Polystyrene gives the whole container a good transparency. Furthermore, since polystyrene has good flow characteristics even at relatively low temperatures, it is a particularly suitable material for injection molding.By using polystyrene for the outermost surface of the inner layer and using polystyrene for the resin for external injection molding, The outer and inner layers are completely integrated to enhance the transparency and rigidity of the container body. Since polypropylene also has relatively good transparency, it has a sufficient transparency depending on the application.

The inner lid thus obtained, which is used for the multi-layer container having good gas barrier properties, must have good sealing properties and gas barrier properties. The inner lid of the present invention comprises a laminated sheet of a crystalline polypropylene layer, an ethylene-vinyl acetate copolymer layer, and a sealant layer. The sealant layer is mainly made of polyethylene, and has a good sealing property during heat sealing. .

On the other hand, the outer lid is made of polypropylene and has good rigidity and transparency, and has an annular projection inside which snap fits with the flange portion of the container body. Since the outer lid is elastically deformed easily, it can be snapped into the container by pressing and can be easily opened by lifting the peripheral edge. By thus providing the outer lid with recloseability, the contents after opening are protected from dust, dust, and the like, and a comfortable feeling of use is brought about.

〔Example〕

 The multilayer container of the present invention will be described in detail below.

FIG. 1 shows an example of the multi-layer container of the present invention.

The multi-layer container 1 is composed of an inner layer 2 having a gas barrier property and an outer layer 3 having transparency and rigidity, and a flange 4 at the upper end peripheral portion.

Details of an optional portion A of the multilayer container are shown in FIG. 2 to show the layer structure of the multilayer container. The multilayer container has a multilayer structure including an inner layer 2 made of a polyethylene terephthalate layer 5, an ethylene-vinyl acetate copolymer layer 6 and a polystyrene layer 7 and an outer layer 3 made of injection-molded polystyrene from the inner surface side. The polystyrene layer 7 of the inner layer 2 and the polystyrene outer layer 3 are separated from each other in the description of the drawings, but in reality, this joint surface is completely integrated, and the two cannot be distinguished.

In the present invention, since the polyethylene terephthalate layer 5 is arranged on the innermost surface that contacts the contents, it is particularly safe when the food is the contents. Furthermore, since the ethylene-vinyl acetate copolymer layer 6 is arranged in the middle of the laminated sheet, the ethylene-vinyl acetate copolymer layer 6 does not drop, and good gas barrier properties are surely brought about.

In the above examples, even when polypropylene is used as the transparent resin instead of polystyrene, the multilayer structure, and the integration of the joint surfaces of the inner layer and the outer layer do not change, and the effect on the food safety and gas barrier property is also the same. A good container body can be obtained.

Due to the above-mentioned multilayer structure, the inner peripheral portion 4a of the flange 4 is
The upper surface of is made of polyethylene terephthalate, but polyethylene terephthalate has poor heat sealability. Therefore, it is preferable that the protrusion width of the inner peripheral portion 4a of the flange 4 is made as small as possible and most of the flange 4 is composed of the outer peripheral portion 4b. Further, the outer peripheral portion 4b of the flange 4 is the flange portion 4a.
Can be injection-molded so that the entire surface of the flange 4 is made of polystyrene.

FIG. 3 is a partially cutaway front view showing an example in which the inner lid 8 and the outer lid 9 are attached to the multilayer container 1. An inner lid 8 is adhered to the multilayer container 1 by heat sealing, and an outer lid 9 is attached so as to cover it.

As shown in FIGS. 3 and 4, the inner lid 8 has the shape of a drop lid, and the edge 10 is adhered to the outer peripheral portion 4b of the flange 4 of the multilayer container 1 by heat sealing.

Further, in the present invention, in order to improve the sealing property of the inner lid, the inner lid 8 is made of three layers of a crystalline polypropylene layer 11, an ethylene-vinyl acetate copolymer layer 12 and a sealant layer 13 as shown in FIG. The sealant layer 13 on the adhesive surface is composed mainly of polyethylene, which has good adhesiveness to polystyrene or polypropylene. The inner lid 8 improves heat sealability, and can enhance the preservability of the contents of the container until the container is opened. Further, by dropping the inner lid 8 to have a lid shape, it is possible to obtain an advantage that a spoon or the like can be accommodated in the space between the inner lid 8 and the outer lid 9.

FIG. 6 shows a partially cutaway front view of the outer lid 9 mounted on the hermetically-sealed container comprising the multilayer container 1 and the inner lid 8 thus obtained. The outer lid 9 made of polypropylene has an annular projection 14 on the inner surface, and the annular projection 14 is the flange 4 of the multilayer container 1.
Is locked to the outer peripheral portion of. Since the outer lid 9 is elastically deformable, the inner diameter of the annular projection 14 is enlarged by pressing, and the annular projection 14 is fitted into the flange 4 and fixed to the container. However, it can be easily attached and detached by lifting the peripheral portion of the outer lid 9. Due to such reclosability, the outer lid 9 prevents the contents of the container after opening the inner lid 8 from directly contacting the air, protects the contents from dust and dust, and provides a comfortable usability. give.

Next, a method of manufacturing the container body of the present invention will be described.
The laminated sheet used as the inner layer is composed of a polyethylene terephthalate layer, an ethylene-vinyl acetate copolymer layer and a transparent resin layer. The thickness of the polyethylene terephthalate layer is generally 40 μm to 80 μm. If it is less than 40 μm, the surface condition is rough and the transparency is impaired.
There is no point in exceeding μm. The thickness of the ethylene-vinyl acetate copolymer layer is generally 25 μm to 45 μm, and if it is less than 20 μm, the gas barrier property is low and the storage stability of the content is impaired, but it is meaningless if it exceeds 50 μm. The thickness of the transparent resin layer does not need to be particularly thick because it is integrated with the outer layer injection-molded resin, but generally 200 μm to 300 μm.
It has a thickness of μm.

The above-mentioned laminated sheet is pre-formed into a cup shape by a sheet forming method such as vacuum forming and pressure forming, and the cup-shaped inner layer 2 is placed in the cavity 17 of the molds 15 and 16, and the transparent resin for the outer layer is formed. Injection molding is performed to form a multilayer container. At the time of this injection molding, the injection molding temperature is 240 ° C to 260 ° C when polystyrene is used as the transparent resin, and 200 ° C when polypropylene is used so that the outer layer and the inner layer are completely integrated. It is preferably 220 ° C. The thickness of the outer layer can be variously changed depending on the size and shape of the container.

The inner lid 8 can be heat-sealed by a usual method, and the heat-sealing temperature is preferably about 170 to 190 ° C.

[Effect of device]

As described above, according to the present invention, it is possible to inexpensively provide a multi-layer container having a uniform wall thickness, excellent rigidity and transparency, and excellent gas barrier properties. Also,
By attaching the inner lid and outer lid of the present invention to the multi-layer container,
The contents can be protected even after opening. Also, the top lid is detachably attached by snap-fitting, so opening and closing is easy.

[Brief description of drawings]

1 is a longitudinal sectional view showing a multi-layer container according to an embodiment of the present invention, FIG. 2 is a partially enlarged cross-sectional view showing the multi-layer structure of the multi-layer container, and FIG. FIG. 4 is a partially cutaway front view showing an example in which a lid and an outer lid are attached, FIG. 4 is a perspective view showing an inner lid of the present invention, and FIG. 5 is a partially enlarged sectional view showing a laminated structure of the inner lid. FIG. 6 is a partially cutaway front view of the outer lid of the present invention, and FIG. 7 is a vertical cross-sectional view showing an injection molding process for manufacturing the multilayer container of the present invention. 1 ... Multi-layer container 2 ... Inner layer 3 ... Outer layer 4 ... Flange 8 ... Inner lid 9 ... Outer lid 14 ... Annular protrusion 15, 16 ... Injection mold 17 ... Cavity

Claims (4)

[Scope of utility model registration request] 1. A multi-layer container comprising an inner layer made of a resin sheet having a gas barrier property and an outer layer integrally formed on the outer surface side of the inner layer by injection molding, wherein the inner layer of the multi-layer container is a polyethylene terephthalate layer from the inside. ,
A multi-layer container comprising an ethylene-vinyl acetate copolymer layer and a transparent resin layer, wherein the outer layer comprises the transparent resin. 2. The multi-layer container according to claim 1, wherein the transparent resin is polystyrene or polypropylene. 3. The multilayer container according to claim 1 or 2, wherein a flange provided at an upper end of the container is mainly composed of a crystalline polypropylene layer, an ethylene-vinyl acetate copolymer layer, and polyethylene from above. A container characterized in that an inner lid made of a sealant layer is adhered by heat sealing. 4. The multi-layer container according to claim 3, further comprising a polypropylene outer lid that covers the inner lid, and an inner ring of the outer lid that is locked to the outer periphery of the flange portion by a snap fit. A container provided with a protrusion.