JPH06285960A - Container made of laminated synthetic resin and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a container which is suitable for holding a commodity apt to deteriorate and storing it for long, by a method wherein a film of thermoplastic polyester resin or the like is positioned on both sides of a film constituted of olefin resin and a laminated film having three layers brought into close contact with each other is made tubular. CONSTITUTION:A tubular film constituted of one resin selected from PET, EVOH and MX is positioned on both sides of a tubular PO film held between and a laminated tube formed of these films only brought into close contact with each other is extruded and used as parison. Molten resin PO prepared in an extruder enters an annular passage 35 inside a head 3. While the circular passage 35 is made concentric with annular passages 31 and 33, it is positioned in the middle of the annular passages 31 and 33 when viewed from the center thereof. The molten resin PO enters a passage 36 from the annular passage 35 and becomes a tubular film which is to form a central layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated synthetic resin container. In particular, the present invention is intended to provide a container suitable for storing a product such as food or cosmetics which is likely to be deteriorated by absorbing moisture or coming into contact with air and stored for a long time.

[0002]

2. Description of the Related Art A laminated synthetic resin container is a container made of a laminated body of synthetic resin films or sheets. Such containers are already known. In this case, the laminated body constituting the container was formed by adhering synthetic resin films or sheets (hereinafter, collectively referred to as a film) constituting the respective layers to each other. That is,
When the synthetic resins composing each layer are of a nature that fuses with each other, they are integrated by fusing each other, and the synthetic resins that compose each layer are of a nature that they do not fuse together. At one point, an adhesive was placed between them to become one. In other words, the container was not made of a laminated body in which the synthetic resins in which the respective layers were not fused to each other were simply brought into close contact with each other. This is because it was considered that the container would peel off during use if the container was made of the laminated body that was only brought into close contact with the container.

On the other hand, a blow molding method is known as one method for producing a container made of synthetic resin. Blow molding is a method used to make bottle-like containers. In the blow molding method, synthetic resin is extruded into a cylindrical shape from an extruder to make a parison, and while the parison is still softening, the parison is sandwiched between split molds and the tip of the parison is closed, and the other end is placed inside the parison. This is a method in which air is blown into the parison to inflate it, the parison is brought into close contact with the wall surface of the outer mold to form a container, and after cooling, the mold is opened and the container is taken out. In the blow molding method, a container having only one layer was often produced.

It has also been proposed to make laminated containers by the blow molding method. The proposal is a method in which a plurality of parisons are extruded separately from a single die in an overlapping state, and the parisons are inflated in a split mold and simultaneously laminated. However, it is troublesome to make the parisons in multiple layers, and it is difficult to make the parisons inflate at the same time as they are laminated. Therefore, it is not easy to make a laminated container by this method.

As an improvement on this point, Japanese Patent Laid-Open No. 56-
There is a proposal of Japanese Patent No. 167442. The proposal is to use one injection molding machine with a movable mandrel and an auxiliary extruder. Then, first, one resin is injected into the mold to make a parison with the resin to be the outer layer, and when the parison is cooled from the outside and the inside of the parison is still softened, another It is said that a multilayer container is formed by injecting resin to form an outer layer / center layer / outer layer, and then the parison is heated and blow-molded to form a laminated container.

[0006] However, it is difficult to make the inside of the parison constituting the outer layer still soft, and in addition, another resin is injected into the parison to make the other resin uniform throughout. It is not easy to make thick. It is also not easy to make an injection molding machine that operates in that way.
Moreover, it is a heat uneconomical and inefficient to have to reheat the multi-layer parison made in the mould.

Further, the above-mentioned Japanese Patent Application Laid-Open No. 56-167442 describes that various resins can be used in combination. However, the combination of the resins that can be used therefor is tentatively fused to each other. It seems to be limited to. In fact, it has not been shown to make a three layer parison with a thermoplastic polyester resin on the outer layer and a polyolefin on the center layer.

On the other hand, a coextrusion method is known for producing a laminated film by extrusion. With co-extrusion, after melting different resins in different extruders,
This is a method in which this is introduced into one die, and each resin is first formed into a film separately, and then the films are joined in the same die to form a laminated film. This method has been used for resins that fuse together. If the resins do not fuse together, it was necessary to interpose an adhesive between them.

[0009]

DISCLOSURE OF THE INVENTION In order to provide a container suitable for containing easily deteriorated products such as foods and cosmetics, the present inventor first needs to provide a resin having a high water-blocking degree and a resin having a high oxygen-blocking degree. I thought it necessary to stack and use. Then, a polyolefin (hereinafter referred to as PO) is used as a resin having a high degree of moisture barrier,
Further, as a resin having a large oxygen blocking degree, a thermoplastic polyester resin (hereinafter referred to as PET), an ethylene / vinyl alcohol copolymer resin (hereinafter referred to as EVOH), and MX nylon (hereinafter referred to as MX) are used. I thought it appropriate to use. However, PO is P
ET, EVOH, MX (hereinafter, these three are collectively referred to as PE
M) and cannot be fused together. That is, they are peeled off even if they are fused with each other. Therefore, it is necessary to interpose an adhesive to bond the PO with the PEM to form a laminated body.

When PO and PEM are laminated,
It was found that when PO is exposed on the surface, the container made of this laminate gives off a peculiar offensive odor to PO, and this offensive odor becomes unsuitable for containing foods and cosmetics. It was Therefore, the present inventor tried to position PO as the central layer and PEM as the outer layer, and found that this can improve the drawback of the offensive odor.

Further, the present inventor thought that the laminated resin container was made by blow molding. When making a container by blow molding, when PO is located in the center layer and PEMs are located on both sides of the container to form a three-layer parison, when an adhesive agent is interposed between them, the parison includes the adhesive agent. It is necessary to make 5 layers. However, it is not easy to mold a five-layer parison.
So we needed to make this even easier.

[0012]

The inventor of the present invention has prepared a laminated parison made of a three-layer film by using PO as a central layer and arranging PEM, that is, PET, EVOH or MX on both sides thereof, to form a laminated parison. However, it has been found that it is convenient to laminate them in a single die by coextrusion and extrude them as a laminated film. In addition, if the laminated parison thus made is made into a wide-bottomed container by the conventional blow molding method, the resin of the parison does not melt together, but the shape of the wide-bottomed container will It has been found that the container does not easily peel into each resin layer. Therefore,
This laminated container has an advantage that it can be sufficiently used as an integrated container without interposing an adhesive layer between each layer. The present invention has been completed based on such knowledge.

The present invention provides a container in one aspect and a method for producing a container in another aspect. The container consists of a tube made of a laminated film in which a film made of one of the PEMs is placed on both sides of a film made of an olefin resin and three layers are brought into close contact with each other. One end of the tube is closed to form a bottom. A container made of laminated synthetic resin, wherein the other end is opened to form a mouth, and the container is integrally bulged in a shape expanding from the mouth toward the bottom.

Further, the container manufacturing method is such that one resin of the PEM is melted in one extruder by co-extrusion, PO is melted in another extruder, and the two melted resins are melted in one die. And form the former into a double tubular film in the die, and form the latter into a single tubular film in the middle position, and join these films in the die to form a tubular laminate. Form a film, extrude from the die to make a parison, sandwich the parison in a split outer mold for container molding, close one end, blow air into the parison from the other end, hollow mold to make a wide container. It is a feature.

[0015]

EXAMPLE An example of implementing the container according to the present invention,
It will be described below with reference to the drawings. FIG. 1 is a partially cutaway side view of a laminated synthetic resin container according to the present invention. FIG. 2 is a model diagram showing a method for manufacturing a laminated synthetic resin container according to the present invention.

[0016]

[Description of Container] In the container shown in FIG. 1, one end of a cylinder made of synthetic resin is closed to form a bottom a, and the other end is opened to form a mouth b. It has a swollen shape. The cylinder is made of a laminated film obtained by laminating films of thermoplastic synthetic resin. In these respects this container is mundane.

The most characteristic feature of the present invention is the constitution of the laminated film. That is, the laminated film is a combination in which the film c made of PO is the central layer and the films d and e made of PEM, that is, PET, EVOH or MX are located on both sides thereof. Since PO and PET, EVOH, or MX are resins that do not fuse with each other, they do not adhere when they are in direct contact, and therefore this laminated film should be disassembled into pieces. Since they bulge in a shape that widens toward, they are locked together and escape from disassembly, and are integrated.

As the PO used in the present invention, either polyethylene or polypropylene can be used.
Among them, polyethylene may be either low density or high density polyethylene.

PET is a high molecular weight chain polyester obtained by reacting an aromatic dicarboxylic acid with a divalent alcohol. The most widely used dicarboxylic acid is terephthalic acid, but there is also one using isophthalic acid. Ethylene glycol is mainly used as the dihydric alcohol, but trimethylene glycol,
Some use diethylene glycol or the like. Since such polyester is commercially available, a commercially available resin is used in the present invention.

EVOH is a copolymer resin of ethylene and vinyl alcohol. This copolymer resin is prepared by copolymerizing ethylene and vinyl acetate to prepare an ethylene / vinyl acetate copolymer, and then hydrolyzing the vinyl acetate in the copolymer. Although there are various copolymerization ratios, in the present invention, the vinyl alcohol content is 20 to
It is preferable to use 50 mol%.

MX is a chain polymer obtained by condensing metaxylylenediamine and a dibasic acid, and is a type of nylon. Adipic acid is often used as the dibasic acid. Since MX is commercially available, a commercially available resin can be used in the present invention.

[0022]

Since the container according to the present invention is constructed as described above, it has the following advantages. That is, since the laminated film has PO as the central layer, it becomes a container that can sufficiently withstand a temperature of about 100 to 120 ° C. In addition, the laminated film has PE on the outside.
Since the T, EVOH or MX film is located,
It is tasteless and odorless and may come into contact with food.
It prevents the emission of the odor peculiar to O, and thus is suitable as a container for foods, cosmetics and the like. Furthermore P
Since O has a high degree of moisture barrier and PET, EVOH or MX have a high degree of oxygen barrier, the laminated film as a whole has a high degree of oxygen and moisture barrier, so this container is suitable for storing foods and cosmetics. It has become. On top of that, it spreads from the mouth to the bottom,
The body of the container is stretched and therefore strong. Furthermore, PO and PEM, that is, P
Since it is only in close contact with ET, EVOH or MX, the transparency is good as long as there is no adhesive,
It is beautiful. Thus, the container of the present invention has various advantages.

[0023]

[Description of Manufacturing Method] Next, a method of manufacturing the container according to the present invention will be described with reference to FIG. In FIG. 2, PEM, ie PET, EVOH or MX is melted in the extruder 1,
PO is melted in the extruder 2 and the melted resin is guided into the die 3. In the base 3, all of these resins are formed into a tubular film, and a film made of PO is used as a central layer, and films made of PEM are positioned on both sides of the film, and these films are joined and laminated in the base. I am making a tube made of film. This tube is extruded from the base to obtain parison 4. After that, according to the conventional method, the parison 4 is sandwiched between the outer mold halves 51 and 52, one end is closed, and air is blown into the parison from the pipe 6 to perform hollow molding, thereby molding the parison into a wide-bottomed container. After that, the mouth of the container is cut, the container is cooled, the outer mold is opened, and the container is taken out.

The method of manufacturing the container shown in FIG.
Put an O film inside and put PET and EVOH on both sides.
Alternatively, it is characterized in that a tubular film made of one resin selected from MX is positioned, a laminated tube in which those films are in close contact is extruded, and this is used as a parison. To explain further, P
Since O and PET, EVOH or MX do not fuse with each other, such resins cannot be integrated without an adhesive agent interposed between them, so it is common sense not to coextrude without an adhesive agent. Met. However, the method of the present invention is characterized in that co-extrusion is performed without interposing an adhesive. According to the method of the present invention,
Even without an adhesive, the parison obtained was immediately blow-molded to form a wide-bottomed container, which prevented the laminated parison from peeling and falling apart. Of.

In FIG. 2, a tube made of a laminated film is produced in the die 3 by co-extrusion, and the mechanism is as follows. The molten PEM produced by the extruder 1 is divided into two in the flow dividing device, one passes through the flow path 71 and the base 3
Entering the inside, the innermost ring passage 3 of the mouthpiece 3
1 into the tubular film that forms the inner layer through the passage 32. On the other hand, the other one, which is divided into two,
It enters into the die 3 through the flow path 72, enters the annular passage 33 located at the outermost side in the die 3, and then passes through the passage 34 to become a tubular film forming an outer layer. Circular passage 3
1 and 33 are concentric.

On the other hand, the molten resin PO produced by the extruder 2
Enters the annular passage 35 in the base 3, but the annular passage 35
Is concentric with the above-mentioned annular passages 31 and 33,
When viewed from the center, it is located in the middle of the annular passages 31 and 33. The molten resin PO enters the passage 36 from the annular passage 35 and becomes a tubular film forming a central layer.

The tubular film thus formed in three layers merges at the passage 37 in the die 3 to form a tube made of a laminated film. This tube is extruded from the base 3 to form the parison 4. The parison 4 is then subjected to conventional blow molding.

[0028]

According to the present invention, PET, EVOH or M
X is melted in one extruder, PO is melted in another extruder, the two molten resins are introduced into one die, and the former is molded into a double tubular film in the die,
The latter is molded into a single tubular film at its intermediate position, and these films are merged in the die to form a tube made of a laminated film.
It is easy to make a three-layer laminated tube with a film of T, EVOH or MX located on it. Since this laminated tube is extruded from the mouthpiece to make a parison, one end is closed by sandwiching this parison in a split outer mold for container molding,
By blowing air into the parison from the other end to perform hollow molding, a laminated synthetic resin container can be easily manufactured. In this container, PO, PET, EV
Since OH or MX have a property that they are not fused to each other, the layers of each resin are originally separated from each other to form a container, but since a wide-bottomed container is formed by blow molding, each layer is It does not fall apart and is firmly integrated. Furthermore, as described above, this container has a great ability to block water and oxygen, and is nontoxic and odorless, so it is valuable as a container for containing easily-altered foods and cosmetics. ing. Further, the layers of the respective resins are in airtight contact with each other, and no adhesive agent is interposed therebetween, so that the transparency is also good. Moreover,
The value of the present invention lies in the fact that such a container can be produced only by the method of the present invention.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a laminated synthetic resin container according to the present invention.

FIG. 2 is a model diagram illustrating an example of a method for manufacturing a laminated synthetic resin container according to the present invention.

[Explanation of symbols]

a bottom of container b mouth of container c film made of olefin resin d thermoplastic polyester resin, ethylene / vinyl alcohol copolymer resin, or MX nylon film e thermoplastic polyester resin, ethylene / vinyl alcohol copolymer resin, or Film made of MX nylon 1 Extruder 2 Extruder 3 Base 4 Parison 5 External type

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B32B 27/32 C 8115-4F D 8115-4F B65D 1/09

Claims (2)

[Claims] 1. A thermoplastic polyester resin, ethylene., On both sides of a film or sheet made of an olefin resin.
A film or sheet made of vinyl alcohol copolymer resin or MX nylon is positioned to form a tube made of a laminated film or sheet in which only three layers are brought into close contact with each other. One end of the tube is closed to form the bottom and the other end is opened. A container made of laminated synthetic resin, characterized in that it is made into a mouth, and is integrally bulged in a shape expanding from the mouth to the bottom. 2. A thermoplastic polyester resin, ethylene
Vinyl alcohol copolymer resin or MX nylon is melted in one extruder, olefin resin is melted in another extruder, and the two melted resins are introduced into one die,
The former is formed into a double tubular film or sheet in the die, the latter is formed into a single tubular film or sheet at an intermediate position, and these films or sheets are joined in the die to form a laminated film or sheet. Make a tube consisting of a sheet, extrude it from the mouthpiece to make a parison, sandwich the parison in a split outer mold for container molding and close one end, blow air into the parison from the other end, and blow mold it into a wide bottom container A method of manufacturing a laminated synthetic resin container, comprising: