JP2020192998A - Extrusion blow-molded container - Google Patents

Abstract

To provide an extrusion blow-molded container which can secure appropriate moldability and strength while using recycled materials.SOLUTION: Of an extrusion blow-molded container 1 made of synthetic resin whose body part 3 forming a storage space S for contents has a laminated structure L made of multiple materials, the laminated structure L has an inner layer 10 and an outer layer 20 made of virgin materials, and a recycled material layer 30 positioned between the inner layer 10 and the outer layer 20, the recycled material layer 30 is composed of olefin-based recycled materials, and the weight ratio of the recycled material layer 30 in the laminated structure L is 50% or more and 90% or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to an extrusion blow molded container formed by extrusion blow molding.

Conventionally, an extrusion blow molded container made of synthetic resin formed by extrusion blow molding has been used as a container for accommodating various contents such as beverages, cosmetics, and detergents. For example, Patent Document 1 describes a synthetic resin made by extrusion blow molding (EBM: Extrusion Blow Molding), in which a cylindrical parison formed by extruding a synthetic resin material is blow-molded using a split mold. Containers are disclosed.

Japanese Unexamined Patent Publication No. 2011-213370

In manufacturing the above-mentioned containers, in recent years, for the purpose of saving energy resources and reducing the environmental load, for example, once used synthetic resin containers are collected and recycled, and the containers are manufactured using recycled materials. It is recommended to do.

However, many of the above-mentioned recycled materials are a mixture of different materials, and the mixing ratio also varies from lot to lot. Therefore, the physical properties of MFR (melt flow rate) and the like are virgin materials (new materials). ) May differ significantly. As a result, when a recycled material is used, the expected moldability may not be obtained even if extrusion blow molding is performed under the same conditions as the virgin material. Specifically, for example, when a parison is extruded and formed, a part of the parison hangs down in the direction of gravity due to its own weight, which is a phenomenon of "drawdown", and the thickness of the container after molding becomes uneven. There is a risk of causing "uneven thickness" or causing bursting during blow molding. Further, a container molded using a recycled material may lack mechanical strength such as stress cracking resistance (ESCR) as compared with a container molded from a virgin material.

Therefore, an object of the present invention is to provide an extrusion blow molded container capable of ensuring appropriate moldability and strength while using a recycled material.

The present invention has been made to solve the above problems, and the extrusion blow molded container of the present invention is an extrusion blow made of a synthetic resin having a body having a laminated structure made of a plurality of materials for forming a storage space for the contents. It is a molded container
The laminated structure has an inner layer and an outer layer made of a virgin material, and a recycled material layer located between the inner layer and the outer layer.
The recycled material layer is composed of an olefin-based recycled material.
It is characterized in that the weight ratio of the recycled material layer in the laminated structure is 50% or more and 90% or less.

Further, in the extrusion blow molded container of the present invention, it is preferable that at least one of the inner layer and the outer layer has a barrier layer having a gas barrier property.

Further, in the extrusion blow molding container of the present invention, it is preferable that the inner layer has a high-density polyethylene layer and the barrier layer located outside the high-density polyethylene layer.

Further, in the extrusion blow molded container of the present invention, it is preferable that the outer layer has a high-density polyethylene layer and the barrier layer located inside the high-density polyethylene layer.

Further, in the extrusion blow molded container of the present invention, the barrier layer preferably contains EVOH or nylon.

Further, in the extrusion blow molded container of the present invention, the recycled material is preferably a post-consumer material.

According to the present invention, it is possible to provide an extrusion blow molded container capable of ensuring appropriate moldability and strength while using a recycled material.

It is a side view and a partially enlarged view which showed the extrusion blow molding container as one Embodiment which concerns on this invention in a partial cross section.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The extrusion blow-molded container 1 according to the present embodiment is, for example, a bottomed tubular container having a cylindrical mouth portion 2 as shown in FIG. 1 and a body portion 3 connected below the mouth portion 2. Can be done.

As shown in FIG. 1, the mouth portion 2 of this example is provided with a male screw 2a on the outer peripheral surface thereof to which a lid or a discharge cap or the like can be screwed, but the present invention is not limited to this. For example, instead of the male screw 2a, an uneven surface that can be undercut and engaged with the lid or the like may be provided on the outer peripheral surface of the mouth 2, and the lid or the like may be attached to the mouth 2 by a stopper or the like.

The body portion 3 of this example includes a shoulder portion 3a that is connected to the lower end portion of the mouth portion 2 and extends downward in the radial direction, and a cylindrical body portion 3b that is connected to the outer peripheral edge portion of the shoulder portion 3a. It has a bottom portion 3c that closes the lower end portion of the body body portion 3b. The bottom portion 3c is provided with a pinch-off portion 3d formed by cutting off the blow molding die. The shapes of the mouth portion 2 and the body portion 3 are not limited to the illustrated examples, and can be changed as appropriate.

The body portion 3 forms a storage space S for the contents, and various contents can be stored in the storage space S. The side wall of the body portion 3 is composed of a laminated structure L made of a plurality of materials.

The laminated structure L constituting the body portion 3 has an inner layer 10 and an outer layer 20 made of a virgin material, and a recycled material layer 30 located between the inner layer 10 and the outer layer 20.

The inner layer 10 may be composed of, for example, a high-density polyethylene (HDPE) layer 11 and a barrier layer 12 having a gas barrier property (oxygen barrier property) which is laminated and arranged so as to surround the high-density polyethylene layer 11 from the outside. it can. In the case of this example, the high-density polyethylene layer 11 is located on the innermost side (the side closest to the accommodation space S) in the laminated structure L, and the barrier layer 12 is located between the high-density polyethylene layer 11 and the recycled material layer 30. positioned. The barrier layer 12 can be, for example, a layer made of EVOH (ethylene-vinyl alcohol copolymer) or nylon (MXD6).

The outer layer 20 can be composed of, for example, a high-density polyethylene layer 21 and a barrier layer 22 located inside the high-density polyethylene layer 21. In the case of this example, the high-density polyethylene layer 21 is located on the outermost side (the side closest to the accommodation space S) in the laminated structure L, and surrounds the barrier layer 22 from the outside. The barrier layer 22 is located between the high-density polyethylene layer 21 and the recycled material layer 30, and surrounds the recycled material layer 30 from the outside. The barrier layer 12 can be, for example, a layer made of EVOH (ethylene-vinyl alcohol copolymer) or nylon. The barrier layers 12 and 22 may be made of a resin other than EVOH or nylon. The inner layer 10 and the outer layer 20 may be made of a virgin material, and the type of the material is not particularly limited. Further, the inner layer 10 and the outer layer 20 may be made of the same material or may be made of different materials. Further, the inner layer 10 and the outer layer 20 may each be composed of a single layer made of a single material, or may be made of a plurality of layers made of a plurality of materials.

Here, it is also possible to provide an adhesive layer between the layers to increase the adhesive strength between the layers. In particular, it is preferable to provide an adhesive layer between the barrier layers 12 and 22 and the layers adjacent to the inside and outside of the barrier layers 12 and 22, respectively.

The recycled material layer 30 is made of an olefin-based recycled material. Here, the "recycled material" includes a pre-consumer material and a post-consumer material (see JIS Q 14021). Pre-consumer materials are materials taken from the flow of waste in the manufacturing process. Specifically, the pre-consumer material can be, for example, unnecessary offcuts generated when a container made of synthetic resin is manufactured. In addition, post-consumer materials are materials discharged from homes or materials generated as products that can no longer be used for their original purposes from commercial facilities, industrial facilities and various facilities as end users of products. , Including materials returned from the distribution channel. Specifically, the post-consumer material can be, for example, a recycled resin such as a crushed product obtained by crushing a container made of recycled synthetic resin. The type of olefin-based recycled material may be, for example, recycled polyethylene (PE) or polypropylene (PP). The recycled material layer 30 of this example can be made of, for example, a material having a content of recycled polyethylene of 60% or more. The recycled material layer 30 may partially contain a virgin material. Further, the recycled material layer 30 may be composed of a single layer made of a single material, or may be made of a plurality of layers made of a plurality of materials.

The laminated structure L of the body portion 3 is configured such that the weight ratio of the recycled material layer 30 is 50% or more and 90% or less. That is, in the laminated structure L, the total weight ratio of the inner layer 10 and the outer layer 20 other than the recycled material layer 30 can be 10% or more and 50% or less.

The molding of the extrusion blow molding container 1 having the above-described configuration is not shown, but for example, the resin constituting each layer is co-extruded from the multi-layer extrusion die to extrude a cylindrical parison (laminated parison). , This is blow molded using a blow molding die located below the die. The blow molding die is, for example, divided into two by a vertical dividing surface including the central axis of the extrusion blow molding container 1. Further, a pinch-off portion of a mold having a cutting edge is provided on the dividing surface.

As described above, in the extrusion blow-molded container 1 of the present embodiment, the laminated structure L of the body portion 3 is a recycled structure located between the inner layer 10 and the outer layer 20 made of a virgin material and the inner layer 10 and the outer layer 20. The recycled material layer 30 has a material layer 30, and the recycled material layer 30 is made of an olefin-based recycled material, and the ratio of the recycled material layer 30 in the laminated structure L is 50% or more and 90% or less. There is. In this way, by covering the recycled material layer 30 made of the olefin-based recycled material from the inside and the outside with the inner layer 10 and the outer layer 20 made of the virgin material, the "drawdown" phenomenon at the time of parison molding can be prevented. It is also possible to suppress a decrease in mechanical strength such as stress cracking resistance.

As described above, according to the extrusion blow molding container 1 of the present embodiment, although the recycled material having unstable physical properties is used for the recycled material layer 30, the extrusion blow molding container 1 as a whole secures appropriate moldability and strength. can do.

Further, according to the extrusion blow molded container 1 of the present embodiment, by using the recycled material for the recycled material layer 30, it is possible to contribute to the reduction of the environmental load by reducing the waste and to reduce the cost. It is also possible.

In addition, when recycled materials are used, the surface texture of the outer surface of the container becomes unstable, making it difficult to decorate the outer surface by printing or hot stamping, or reducing the durability of the surface decoration. There is a risk. However, according to the extrusion blow-molded container 1 of the present embodiment, by providing the outer layer 20 made of a virgin material on the outside of the recycled material layer 30, the decorativeness of the outer surface of the container as described above is lowered and the decorativeness is lowered. It is possible to suppress a decrease in the durability of surface decoration.

In addition, many recycled materials have colored pellets themselves, which may reduce the degree of freedom in design. However, in the present embodiment, the recycled material layer 30 is covered with the outer layer 20 from the outside to reduce the degree of freedom of the design. The color of the layer 30 can be made difficult to see from the outside. As a result, according to the extrusion blow molded container 1 of the present embodiment, the degree of freedom in design can be appropriately secured.

Here, from the viewpoint of making the color of the recycled material layer 30 difficult to see from the outside as described above, the thickness of the outer layer 20 is preferably 50 μm or more.

Further, the recycled material has a problem that an odor problem is more likely to occur than the virgin material. However, in the present embodiment, the recycled material layer 30 is covered from the inside and the outside so as to be sandwiched between the inner layer 10 and the outer layer 20, so that the odor is generated. It can be made difficult to be transmitted to the accommodation space S side and the outside side.

Further, from the viewpoint of preventing the transmission of odor as described above, the thickness of the inner layer 10 is preferably 10 μm or more, and similarly, the thickness of the outer layer 20 is also preferably 10 μm or more.

Here, at least one of the inner layer 10 and the outer layer 20 preferably has barrier layers 12 and 22 having a gas barrier property (oxygen barrier property). In this example, the inner layer 10 and the outer layer 20 have barrier layers 12 and 22, respectively, but the present invention is not limited to this, and only one of the inner layer 10 and the outer layer 20 may have a barrier layer, or both. In any case, the configuration may not have a barrier layer.

When the barrier layer 12 is provided on the inner layer 10 as in this example, the odor of the recycled material layer 30 adheres to the contents of the accommodation space S by covering the recycled material layer 30 from the inside with the barrier layer 12. It is possible to prevent such things as doing. Further, by improving the oxygen barrier property of the body portion 3 by the barrier layer 12, it is possible to prevent deterioration of quality due to oxidation of the contents. When the content is an oil-based liquid, the quality is likely to deteriorate due to oxidation, so that the effect of providing the barrier layer 12 is high.

Further, when the barrier layer 22 is provided on the outer layer 20, the oxygen barrier property of the body portion 3 can be improved, so that deterioration of quality due to oxidation of the contents contained in the accommodation space S can be prevented. Can be done. When the content is an oil-based liquid, the quality is likely to deteriorate due to oxidation, so that the effect of providing the barrier layer 22 is high.

Hereinafter, examples of the present invention will be described. Tests were conducted on Examples 1 to 4 according to the present invention and Comparative Examples 1 and 2 not included in the present invention to confirm the effect of the present invention. The extrusion blow molded containers of Examples 1 to 4 and Comparative Examples 1 and 2 have the outer shape shown in FIG. 1, the total weight is 31 g, and the volume of the accommodation space S is 335 ml.

In Examples 1 to 4 and Comparative Examples 1 and 2, the weight ratio (%) of the recycled material layer 30 in the laminated structure L of the body portion 3 is different from each other. The weight ratio ratios (%) of the inner layer 10, the outer layer 20, and the recycled material layer 30 of Examples and Comparative Examples are as shown in Table 1. For each of Examples and Comparative Examples, the moldability in the extrusion blow molding process was evaluated, and the mechanical properties (strength) of the container after molding were evaluated.

Here, in the evaluation of "formability of parison" shown in Table 1 (implemented at N = 500), the materials corresponding to the inner layer 10, the outer layer 20, and the recycled material layer 30 are extruded into a cylindrical shape in a laminated state to obtain the parison. It shows the moldability at the time of molding. When the extruded laminated structure parison is molded into the desired shape and no drawdown phenomenon occurs at all, it is marked as "○", and when the parison has the desired shape but foaming, etc. Was set to "△". In addition, in the evaluation of "moldability at the time of blow (formability)" (implemented at N = 500), the container was molded as expected by blow molding using each parison, and there was no rupture or deformation. The case where it did not occur was evaluated as “◯”, the case where molding was possible but a slight uneven thickness was generated was evaluated as “Δ”, and the case where it ruptured and could not be formed appropriately was evaluated as “x”. Regarding the evaluation of "mechanical properties (strength)" (conducted at N = 5), a drop impact test at a low temperature (after filling the specified amount, 1 m at a product temperature of 5 ° C.) was performed on each container after molding. (Drop from height) was performed, and the case where cracks such as cracks did not occur in the container was marked with "○", and the case where cracks such as cracks occurred in the container was marked with "x".

The evaluation results of Examples 1 to 4 and Comparative Examples 1 and 2 are as shown in Table 1. As shown in Table 1, it was confirmed that appropriate moldability and strength can be ensured for the containers of Examples 1 to 4. Further, in particular, with respect to Examples 2 to 4 in which the weight ratio ratio of the recycled material layer 30 is 80% or less, more preferable moldability than in Example 1 in which the weight ratio ratio of the recycled material layer 30 is 90%. It was confirmed that

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the shape of the body body 3b of the body 3 is a cylindrical shape having a circular cross section perpendicular to the axis, but the cross section is not limited to this, and the cross section is elliptical, polygonal, or the like. The shape may be. Further, the material, thickness, etc. of each layer constituting the inner layer 10, the outer layer 20, and the recycled material layer 30 can be appropriately changed.

1: Extruded blow molded container 2: Mouth 2a: Male screw 3: Body 3a: Shoulder 3b: Body body 3c: Bottom 3d: Pinch-off part 10: Inner layer 11: High-density polyethylene layer 12: Barrier layer 20: Outer layer 21 : High-density polyethylene layer 22: Barrier layer 30: Recycled material layer L: Laminated structure S: Storage space

Claims (6)

An extruded blow-molded container made of synthetic resin having a laminated structure made of a plurality of materials in a body forming a storage space for the contents.
The laminated structure has an inner layer and an outer layer made of a virgin material, and a recycled material layer located between the inner layer and the outer layer.
The recycled material layer is composed of an olefin-based recycled material.
An extruded blow-molded container characterized in that the weight ratio of the recycled material layer in the laminated structure is 50% or more and 90% or less. The extrusion blow-molded container according to claim 1, wherein at least one of the inner layer and the outer layer has a barrier layer having a gas barrier property. The extrusion blow-molded container according to claim 2, wherein the inner layer has a high-density polyethylene layer and the barrier layer located outside the high-density polyethylene layer. The extrusion blow-molded container according to claim 2 or 3, wherein the outer layer has a high-density polyethylene layer and the barrier layer located inside the high-density polyethylene layer. The extrusion blow molded container according to any one of claims 2 to 4, wherein the barrier layer contains EVOH or nylon. The extrusion blow molded container according to any one of claims 1 to 5, wherein the recycled material is a post-consumer material.

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