JPH048294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a container made of synthetic resin. In particular, the present invention relates to a container made of synthetic resin that is easy to manufacture, heat resistant, transparent, strong and impact resistant, and does not easily alter the contents.

(Prior Art) A film made by bonding various thermoplastic resin films together is already known as a laminated film. Laminated film is the result of combining individual thermoplastic resin films that are bonded together.
It has properties that cannot be obtained with a single resin film. Therefore, laminated films have already been used in various fields as resins for constructing containers.

However, a container made of a laminated film that is satisfactory for holding items that are easily deteriorated, such as foodstuffs, cosmetics, medicines, etc., has not yet been obtained. This is because the laminated film is easily permeable to gas and water vapor, and when used as a container, the container is likely to buckle and deform. For this reason, containers made of glass or metal have been used exclusively to store items that are susceptible to deterioration.

However, glass has another fatal flaw: it is easily broken, and metal has yet another fatal flaw: it is opaque, making it impossible to see the contents. Therefore, despite the above-mentioned drawbacks, there is a movement to use synthetic resins as containers for storing articles that are susceptible to deterioration. Therefore, it has been desired to improve synthetic resin containers so as not to deteriorate the container. What alters the contents is
This is thought to be because synthetic resins allow gas and water vapor to permeate. Therefore, in order to prevent the contents from deteriorating, it is necessary to reduce the permeability of gas and water vapor, that is, to provide barrier properties to the synthetic resin. was needed. At the same time, there was a need for something that was easy to mold, had good elasticity, good impact resistance, and did not easily lose its shape.

Japanese Utility Model Publication No. 57-41132 discloses making a container body from a laminated film in order to provide a food container that has the appearance of a metal container but can be vacuum formed. The laminated film is said to have a polyolefin film on the inner surface, a polycarbonate film on the outside, and an aluminum vapor-deposited film and a polyvinylidene chloride film in between. At that time, a polyolefin film is interposed between the polyvinylidene chloride film and the polycarbonate film. However, since this laminated film requires a vapor-deposited aluminum film, it has the disadvantage that it is not easy to manufacture.

Further, JP-A-60-179255 discloses that a container is made from a multilayered laminate by providing an intermediate layer made of a thermoplastic resin having gas barrier properties between polycarbonate resin layers. Here, it is said that polyacrylonitrile, polyester, and a copolymer of ethylene and vinyl alcohol can be mainly used as the resin having gas barrier properties. However, all of these resins were highly hygroscopic and therefore did not have sufficient barrier properties. Furthermore, it was said that the resin with gas barrier properties must be able to be directly fused to the polycarbonate resin, so polyvinylidene chloride resin could not be used as an intermediate layer. The reason is that polyvinylidene chloride resin cannot be directly fused to polycarbonate resin. Therefore, according to this disclosure, it was not possible to produce a container with good barrier properties.

(Problems to be Solved by the Invention) The present invention seeks to provide a container that has particularly high barrier properties and also has other properties. In other words, it is a synthetic material that is transparent and easy to mold, has heat resistance, is strong, has high impact resistance, and has a high barrier property so that it does not easily deteriorate the quality of the product even if it contains a product that is prone to deterioration. The purpose is to provide a container made of resin.

This inventor selected polycarbonate (hereinafter referred to as PC) from a large number of thermoplastic resins,
We focused on the combination with vinylidene chloride resin (hereinafter referred to as PVDC).

In general, PC has the advantages of being transparent, heat resistant, strong and tough. However, PC has the drawback of high water absorption and therefore poor barrier properties. On the other hand, PVDC
It has the advantage of being transparent, having good barrier properties, being impermeable to gases and water vapor, and being non-flammable. However, PC and PVDC cannot be bonded to each other even if they are melted and bonded together. Therefore, until now it has not been possible to obtain a laminated film of PC and PVDC.

(Means for solving the problem) This inventor used other resins to
I tried pasting PVDC together. the result,
We have discovered that PC and PVDC can be bonded together by using an adhesive resin mainly composed of polyolefin. We also discovered that when PC and PVDC are bonded together using an adhesive resin mainly composed of polyolefin, the drawback of PC, such as poor barrier properties, is improved, and as a result, materials that are easily deteriorated become less likely to deteriorate. Furthermore, the adhesive resin, which is mainly made of polyolefin, is not itself transparent, so in order to make the laminated film transparent, the adhesive resin layer must be made thinner. It was confirmed that the adhesive was strong even when the adhesive was used. This invention was completed based on such knowledge and confirmation.

This invention relates to a synthetic resin container obtained by sandwiching a PVDC film between PC films, bonding these together with an olefin resin (hereinafter referred to as AD) to form a laminated film, and bending this laminated film. It is something.

(Example) This invention will be described below with reference to an example. FIG. 1 is a partially cutaway perspective view of a synthetic resin container according to the present invention. FIG. 2 is a partially enlarged view of FIG. 1.

Container A in FIG. 1 is made of laminated film, as shown enlarged in FIG. 2. The laminated film is made by sandwiching a PVDC film, that is, a vinylidene chloride resin film 2, between a PC film, that is, a polycarbonate film 1, and
That is, they are bonded together using an adhesive resin 3 mainly made of olefin resin to form an integrated structure. In other words, this laminated film can be used for PC, AD,
The five layers of PVDC, AD, and PC exist in this order and are integrated. Container A is formed by bending this laminated film to have a bottom and side walls.

Here, PC refers to a large number of carbonate bonds in the main chain of the molecule, that is, It is a resin with a structure of PC is made from bisphenol A and phosgene or diphenyl carbonate. PC film is made by heating and melting PC and rolling it with rolls or extruding it through slits. It is appropriate that the thickness of the PC film is 30 to 300 microns.

PVDC is a resin having a structure of many vinylidene chloride bonds, that is, [ _-CH2 - _Ccl2 ]-n, in the main chain of the molecule. PVDC is commonly commercially available as a copolymer of vinylidene chloride and vinyl chloride or acrylonitrile. In this invention, any of them can be used. PVDC films are made by heating and melting PVDC and rolling it with rolls or extruding it through a slot. The thickness of the PVDC is suitably between 10 and 80 microns.

AD is an adhesive resin mainly composed of olefin resin. For example, it is a resin sold by Mitsui Petrochemicals Co., Ltd. under the name Admer, a resin sold by Mitsubishi Yuka Co., Ltd. under the name Modytsuk, and a resin sold by Mitsubishi Chemical Co., Ltd. under the name Novatec AP.
This is a resin sold under the name . AD can be made into a film by heating and melting it. Since AD is mainly composed of olefin resin, it is inherently translucent. Therefore,
AD is used to make the resulting laminated film transparent, which is much thinner than PC or PVDC films. AD is used as a film with a thickness of 5 to 30 microns.

Various methods can be used to bond a PC film and a PVDC film together using an AD film. That is, either a lamination method or a coextrusion method can be employed. The lamination method is a method in which resin films are first made, and then these films are stacked and welded to form a single body. The coextrusion method is a method in which a plurality of extruders are used to form all the films in one die, and at the same time, they are overlapped and welded to be integrated. The coextrusion method is further subdivided into the feedblock method and the multi-manifold method.
The laminated film of the present invention can be made using any of these methods.

The laminated film thus obtained is heated and softened to form a container. To make a container, a mold having the shape is used and the laminated film is pressed against the mold. The mold used in this case is
A mold consisting of two molds, a female mold and a male mold, may be used, or only one mold corresponding to the female mold or the male mold may be used and pressed against the mold by air pressure. When using air pressure, pressurized air can be sent to the side of the laminated film from the side opposite to the mold to press the laminated film against the mold, or the laminated film can be pressed into the mold by reducing the pressure between the laminated film and the mold. You can also force it. A container according to the present invention is thus formed into a shape having a bottom and side walls.

(Effect of the invention) The container according to this invention has a
It is made of a laminated film made by sandwiching PVDC films and bonding them together using AD. PC and
PVDC is a resin that is difficult to weld to each other, but because AD was interposed between them, the whole was strongly adhered to form a strong laminated film, and a strong container was therefore formed. Moreover, since the container contains a PVDC film inside, it has practically sufficient gas and water vapor barrier properties. Additionally, both PC and PVDC are transparent, and adhesive resins are translucent or thin so they are transparent, so the container is transparent. Furthermore, since PC film is interposed on both sides, it is heat resistant and strong, and has high impact resistance. Therefore, this container is transparent, heat resistant, strong, and impact resistant, and has the characteristics that when a substance that is easily denatured is put therein, the substance is not easily denatured.

In addition, the above-mentioned laminated film can be easily deformed if it is heated strongly and softened.
It can be easily formed into a container by vacuum forming, pressure forming, or the like. Moreover, since the container of this invention has PC films on both sides, it does not deform even when immersed in hot water, and can therefore be sterilized by steam heating. It will be suitable for inclusion. In addition, there is PC on the surface, which is harmless, and AD inside it is also a harmful resin, so it can be brought into direct contact with food products, so in this respect too, food containers It is suitable as

Examples of products suitable for placing in the container of the present invention include retort curry, retort stew, soup, pudding, jelly, yokan,
These include hamburgers, pizza, kamaboko, and rice. All of these containers are used by boiling or retort sterilization, or by heating the container, and this container is suitable for use in such a heated state. Additionally, this container can be placed in the microwave while still containing cooked food.

The container according to the present invention is used by putting foodstuffs or the like therein and then attaching a lid thereon to seal the container. Although the same laminated film can be used as the lid, it is preferable that the lid be thinner than the container. Moreover, aluminum foil can also be used as the lid. The lid is attached to the container in close contact with the container by extrusion coating the surface of the lid that comes into contact with the container with an easily removable adhesive. When you need to take out something inside the container, pinch part of the lid, peel it off, and take out the contents. When the surface of the lid is a PC film, a metal vapor deposition film and printing are attached to it,
When the lid is made of aluminum foil, printing can be applied to it to increase its commercial value.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a synthetic resin container according to the present invention. FIG. 2 is an enlarged view of the portion in FIG. 1. In the figure, 1 is a polycarbonate film,
2 is a vinylidene chloride resin film, and 3 is an olefin resin film.

Claims (1)

[Claims] 1. A synthetic resin container obtained by sandwiching a vinylidene chloride resin film between polycarbonate films, bonding them together with an olefin resin to form a laminated film, and bending the laminated film.