JP2018052616A - Double container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double container having an inner layer body which is a single layer but has high gas barrier property, durability, and moldability.SOLUTION: In a double container (1) having an inner layer body (3) capable of deforming volumetrically containing contents and an outer layer body (2) accommodating the inner layer body (3) inside, the inner layer body 3 was composed of a blend material obtained by melting and kneading a polypropylene resin, an ethylene vinyl alcohol copolymer resin, a master batch for PP, and a compatibility accelerator, and the proportion of the total amount of the master batch for PP and the compatibility accelerator in the blend material is 20 wt% or more and 35 wt% or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a double container having a volume-deformable and deformable inner layer body that contains contents and an outer layer body that contains the contents inside.

  Containers used for containing food seasonings, cosmetics such as lotions, toiletries such as shampoos, rinses or liquid soaps as contents include a volume-reducible and deformable inner layer containing the contents, and this A double container having an outer layer body that accommodates a content body inside is known. The double container is formed by laminating the outer layer body and the inner layer body integrally, and then separating and separating the inner layer body from the outer layer body (a delamination container), and the outer layer body and the inner layer body individually. There are containers of the type that are formed and assembled together after formation.

  A double container cap having a spout for pouring out the contents and a check valve for preventing intrusion of outside air from the spout into the inner layer body is attached to the mouth of the double container. When the outer layer body is pressed, the inner layer body is pressurized and the contents are poured out from the spout. On the other hand, when the pressure on the outer layer body is released after the contents are poured out, outside air is taken in between the outer layer body and the inner layer body through the through holes provided in the outer layer body as the outer layer body is restored, and the volume of the inner layer body is reduced. Only the outer layer body is restored to its original shape while being deformed. Thereby, it becomes possible to pour out the contents without taking outside air into the inner layer body, and deterioration of the contents can be suppressed.

  The inner layer of such a double container is required to have a high gas barrier property against oxygen and the like, a high durability that does not cause cracks and pinholes due to volumetric deformation, and a good moldability when blow-molding the double container. It is done. If attention is paid only to durability and moldability, the inner layer body may be formed from an olefin resin such as polyethylene resin or polypropylene resin, but in this case, it is difficult to ensure high gas barrier properties. On the other hand, if the inner layer body is formed of an ethylene vinyl alcohol copolymer resin, a high gas barrier property can be secured, but in this case, it is difficult to ensure high durability and moldability.

  Therefore, for example, as shown in Patent Document 1, an inner layer is a multilayer in which a layer formed of an ethylene vinyl alcohol copolymer resin and a layer formed of an olefin resin (polyethylene resin) are stacked via an adhesive layer. By adopting a structure, a technology has been developed that achieves both high gas barrier properties and high durability and moldability.

JP 2000-335635 A

  However, when the inner layer body has a multilayer structure like the conventional double container, a plurality of pieces for forming a laminated parison are formed in a molding apparatus for extrusion blow molding (EBM) of the double container. There is a problem that the manufacturing cost is increased, for example, it is necessary to provide an extrusion cylinder.

  On the other hand, a method of forming the inner layer body into a single layer by using a blend material obtained by melting and kneading an olefin resin and an ethylene vinyl alcohol copolymer resin can be considered. However, in this case, if the blend material contains an ethylene vinyl alcohol copolymer resin at a ratio that can ensure a high gas barrier property, there arises a problem that the durability and moldability cannot be ensured. It will be.

  This invention is made | formed in view of such a subject, The objective is to provide the double container which has an inner-layer body provided with high gas barrier property, durability, and a moldability though it is a single layer. .

  The double container of the present invention is a double container having a volume-reducing and deformable inner layer body that contains the contents and an outer layer body that contains the inner layer body inside, and the inner layer body is made of polypropylene resin, ethylene It consists of a blend material formed by melting and kneading a vinyl alcohol copolymer resin, a PP masterbatch and a compatibilizer, and the total ratio of the PP masterbatch and the compatibilizer in the blend material is 20 wt% or more, It is characterized by being 35 wt% or less.

  The double container of the present invention, in the above configuration, the proportion of the polypropylene resin in the blend material is 30 wt% or more, 40 wt% or less, the proportion of the ethylene vinyl alcohol copolymer resin in the blend material is 30 wt% or more, It is preferable that it is 40 wt% or less.

  In the double container of the present invention, in the above configuration, the ratio of the master batch for PP in the blend material is 3 wt% or more and 10 wt% or less, and the ratio of the compatibilizer in the blend material is 20 wt% or more, 30 wt%. % Or less is preferable.

  In the double container of the present invention, the PP master batch is mainly composed of low-density polyethylene, modified with 0.01 to 2.00 wt% of maleic anhydride, and the terminal functional group is a hydroxyl group. A polymer is preferred.

  In the double container of the present invention, the compatibilizer is preferably maleic acid-modified polyolefin.

  In the double container of the present invention, the outer layer body is preferably formed of a polyethylene terephthalate resin in the above configuration.

  In the double container of the present invention, the PP master batch and the compatibilizing agent preferably each have a melting point of 100 ° C. or higher.

  The ethylene vinyl alcohol copolymer resin preferably has an ethylene content of 38 mol% or less.

  ADVANTAGE OF THE INVENTION According to this invention, the double container which has an inner-layer body provided with high gas-barrier property, durability, and a moldability can be provided, although it is a single layer.

It is a front view which shows the double container which is one embodiment of this invention in the state which notched a part.

  Hereinafter, the present invention will be described in more detail with reference to the drawings.

  A double container 1 according to an embodiment of the present invention shown in FIG. 1 is configured as a delamination container, and has an outer layer body 2 and an inner layer body 3.

  The outer layer body 2 is formed of a resin material into a bottle shape having a mouth portion 2a formed in a cylindrical shape with a circular cross section and a body portion 2b integrally connected below the mouth portion 2a. It constitutes the outer shell. The trunk | drum 2b has flexibility, and while being pressed (squeezed), it can dent and can restore | restore from the dent state to the original shape. The mouth 2a is provided with an outside air introduction hole 4. The outside air introduction hole 4 passes through the mouth portion 2 a and communicates between the outer layer body 2 and the inner layer body 3.

  The inner layer body 3 is accommodated inside the outer layer body 2 and is detachably laminated on the inner surface of the outer layer body 2. The inner layer body 3 has a thin bag shape, the opening is connected to the opening end of the mouth portion 2a of the outer layer body 2, and the inside is a housing portion 3a continuous to the opening. For example, contents (content liquid) such as food seasonings, cosmetics such as lotion, toiletries such as shampoo, rinse, or liquid soap can be stored in the container 3a. The inner layer body 3 can be deformed so as to reduce the volume of the accommodating portion 3a as the contents are poured out. That is, the inner layer body 3 is freely volume-deformable.

  A male screw 2c is provided in the mouth portion 2a of the double container 1, and a cap (not shown) for double container is attached to the mouth portion 2a by screw connection by the male screw 2c. As the double container cap, a cap having a spout for pouring out the contents and a check valve for preventing intrusion of outside air from the spout into the inner layer body 3 is used. By pressing the outer layer body 2 and pressurizing the inner layer body 3 with the double container cap mounted, the contents can be poured out from the spout of the double container cap. On the other hand, when the pressing of the outer layer body 2 is released after the contents are poured out, the outer layer body 2 and the inner layer body 3 are connected through the outside air introduction hole 4 provided in the mouth portion 2a of the outer layer body 2 as the outer layer body 2 is restored. Outside air is taken in, and only the outer layer body 2 is restored to its original shape while the inner layer body 3 is deformed and deformed. Thereby, it becomes possible to pour out the contents without taking outside air into the accommodating portion 3a of the inner layer body 3, and deterioration of the contents can be suppressed.

  In the present embodiment, the resin material forming the outer layer body 2 is a polyethylene terephthalate resin (PET resin).

  On the other hand, the inner layer body 3 is configured as a single layer by a blend material obtained by melting and kneading a polypropylene resin (PP), an ethylene vinyl alcohol copolymer resin (EVOH), a master batch for PP, and a compatibilizing agent. The ratio of the PP master batch and the compatibilizer in the blend material constituting the inner layer body 3 (the ratio of the ratio of the master batch for PP and the ratio of the compatibilizer) is the weight percent concentration (mass). The percent concentration) is 20 wt% or more and 35 wt% or less. By forming the inner layer body 3 into a single layer with the above-described blend material, the inner layer body 3 can have high gas barrier properties, durability, and moldability.

  Here, the inner layer body 3 used for the double container 1 has a high gas barrier property against oxygen and the like, a high durability that does not cause cracks and pinholes due to volumetric deformation, and good when the double container 1 is blow-molded. In order to have moldability, when forming a single layer with a blended material obtained by melting and kneading a polypropylene resin having high durability and moldability and an ethylene vinyl alcohol copolymer resin having high gas barrier properties, for example, When the blend material contains an ethylene vinyl alcohol copolymer resin at a ratio that can ensure high gas barrier properties, there is a problem that the durability and moldability cannot be ensured. It will be. In contrast, in the case where the inner layer body 3 is formed as a single layer by a blend material containing a polypropylene resin and an ethylene vinyl alcohol copolymer resin, the applicant of the present invention uses the blend material as a polypropylene resin and an ethylene vinyl alcohol copolymer. In addition to resin, PP masterbatch and compatibilizer are added in the above proportions, so that the inner layer 3 has a single layer and has high gas barrier properties, durability and moldability. And found that can.

  That is, when the blend material includes a master batch for PP, when the polypropylene resin and the ethylene vinyl alcohol copolymer resin are melted and kneaded, the resin is prevented from being gelled or deteriorated. The formability when the inner layer body 3 is molded can be enhanced by a blend material obtained by blending the above resins. The PP masterbatch is one in which a part of the olefin resin is modified with an unsaturated carboxylic acid. Examples of the olefin resin include polypropylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, and high density polyethylene. As the master batch for PP, it is preferable to use a master batch mainly composed of a low density polyethylene resin (LDPE resin). The unsaturated carboxylic acid used for modification is preferably maleic anhydride. The modification amount of maleic anhydride is preferably 0.01 to 2.00 wt%. The optimal form is a master batch for PP, which is a polymer whose main component is low-density polyethylene, modified with 0.01 to 2.00 wt% maleic anhydride, and whose terminal functional group is a hydroxyl group. Further, the melting point can be changed by changing these compositions. By using such a master batch for PP, it is possible to more effectively enhance the formability when the inner layer body 3 is formed from the blend material.

  In addition, by blending the blend material with a compatibilizing agent, when melting and kneading the polypropylene resin and the ethylene vinyl alcohol copolymer resin, it is promoted that these resins are compatible with each other and bonded. The durability of the inner layer body 3 formed from the blend material can be improved. As the compatibilizing agent, for example, adhesive polyolefin can be used, but maleic acid-modified polyolefin is preferably used. More preferred is maleic acid-modified polypropylene. By using maleic acid-modified polyolefin as a compatibilizing agent, the durability of the inner layer body 3 can be increased more effectively.

  Thus, according to the double container 1 of the present embodiment, the inner layer body 3 is made of a blend material obtained by melting and kneading a polypropylene resin, an ethylene vinyl alcohol copolymer resin, a master batch for PP and a compatibilizing agent. Since the ratio of the total amount of the master batch for PP and the compatibilizer is 20 wt% or more and 35 wt% or less in terms of weight percent concentration, the inner layer body 3 is formed as a single layer. It is possible to have a high gas barrier property, durability and moldability while being a single layer.

  In the blend material, the PP master batch ratio is 3 wt% or more and 10 wt% or less in terms of weight percent concentration, and the compatibilizer ratio is 10 wt% or more and 30 wt% or less in terms of weight percent concentration. Is preferable. By including the master batch for PP and the compatibilizing agent at such a ratio, the durability and moldability of the inner layer body 3 can be further improved.

  In the blend material, the proportion of the polypropylene resin is 30 wt% or more and 40 wt% or less in terms of weight percent, and the proportion of the ethylene vinyl alcohol copolymer resin is 30 wt% or more in terms of weight percent. It is preferable to be 40 wt% or less. By having the blend material contain a polypropylene resin and an ethylene vinyl alcohol copolymer resin at such a ratio, the inner layer body 3 has better durability and moldability while ensuring a desired gas barrier property. can do.

  Furthermore, as the ethylene vinyl alcohol copolymer resin constituting the blend material, those having various ethylene contents can be used, and those having an ethylene content of 38 mol% or less are particularly preferable. By using an ethylene vinyl alcohol copolymer resin having an ethylene content of 38 mol% or less, the inner layer body 3 can have better durability and moldability while ensuring desired gas barrier properties.

  For example, random polypropylene can be used as the polypropylene resin constituting the blend material.

  The double container 1 is prepared, for example, by separately preparing an outer layer preform formed by injection molding of polyethylene terephthalate resin and an inner preform formed by injection molding of the above blend material. The inner preform 3 is accommodated inside the outer layer body 2 by incorporating the inner preform inside the reform to form a preform assembly, and this preform assembly is biaxially stretch blow molded using a blow molding apparatus. Can be formed into a double container 1. As a blow molding apparatus for performing biaxial stretch blow molding, a blow molding die on which a preform assembly is set, a stretching rod for longitudinally stretching the preform assembly, and a medium such as air or liquid for blow molding are used. A thing provided with the supply device which supplies to a preform assembly can be used.

  Here, when the outer layer body 2 is formed of a polyethylene terephthalate resin as in the present embodiment, a PP masterbatch and a compatibilizing agent in the above blend material are selected with melting points of 100 ° C. or more, respectively. It is preferable to do this. Thereby, even when the outer layer body 2 is formed of a polyethylene terephthalate resin, when the preform assembly having the above-described structure is blow-molded into the double container 1, the moldability of the blend material is kept high. Can do.

  The double container 1 is an extrusion blow in which a polyethylene terephthalate resin forming the outer layer body 2 and a blend material forming the inner layer body 3 are extruded by coextrusion to form a laminated parison, which is sandwiched between molds and blow-molded. You may make it shape | mold by shaping | molding. In this case, since the inner layer body 3 having high gas barrier properties, durability, and moldability can be configured as a single layer, the number of extrusion cylinders for forming the laminated parison is two for the outer layer body and the inner layer body. As a result, the manufacturing cost of the double container 1 can be reduced.

  In order to confirm the effect of the present invention, five types of inner layer bodies of Examples 1 to 5 and six types of inner layer bodies of Comparative Examples 1 to 6 are prepared, and the moldability and gas barrier properties of each inner layer body are prepared. An experiment was conducted to evaluate The inner layer bodies of Examples 1 to 5 and the inner layer bodies of Comparative Examples 1 to 6 each have a single layer structure, and each includes a polypropylene resin (random PP) and an ethylene vinyl alcohol copolymer resin (ethylene content). 38 mol%), the master batch for PP (RG100 manufactured by Nippon Synthetic Chemical Co., Ltd. (melting point: 100 ° C. or higher)) and the compatibilizer (Modic P587 manufactured by Mitsubishi Chemical Co., Ltd.) It is.

  For the evaluation of moldability, “good” indicates “good”, and “non-moldable (including inner bag cannot be peeled)” indicates “poor”. The gas barrier property was evaluated by measuring oxygen permeation through the inner bag after filling at 80 ° C. and absorbing moisture. The oxygen permeability “less than 0.4 cc / day · pack” was marked with “◯”, and the oxygen permeability “0.4 cc / day · pack or more” was marked with “X”. In addition, when the moldability was evaluated as x (unmoldable) and the gas barrier property could not be evaluated or measured, the item was set to “−” indicating unrated (unmeasured). The oxygen permeability was measured using OX-TRAN 2/20 manufactured by MOCON under the conditions of outside: 22 ° C.-55% RH, 21% oxygen, inside: 22 ° C.-90% RH.

  Table 1 shows the evaluation results.

  From Table 1, in Comparative Example 1 in which all the inner layer bodies were polypropylene resins, moldability was ensured but gas barrier properties could not be ensured, and all the inner layer bodies were ethylene vinyl alcohol copolymer resins. In Comparative Example 2, it can be seen that the gas barrier property can be secured, but the moldability cannot be secured.

  On the other hand, as shown in Comparative Example 3, the moldability is ensured when the ratio of the ethylene vinyl alcohol copolymer resin is insufficient even when the inner layer body includes a polypropylene resin and an ethylene vinyl alcohol copolymer resin. It can be seen that the gas barrier property cannot be secured even if it is possible. Further, as shown in Comparative Example 4, in the case where the inner layer body is configured to include a polypropylene resin and an ethylene vinyl alcohol copolymer resin, in order to increase the gas barrier property, the ratio of the ethylene vinyl alcohol copolymer resin is increased. It can be seen that the moldability cannot be ensured.

  On the other hand, as shown in Examples 1 to 5, the inner layer body is a blend material containing a polypropylene resin, an ethylene vinyl alcohol copolymer resin, a master batch for PP and a compatibilizing agent, and for PP in this blend material. It was confirmed that the moldability and gas barrier property of the inner layer body can be ensured by setting the total ratio of the master batch and the compatibilizer to 20 wt% or more and 35 wt% or less. Also, when the PP masterbatch ratio is 3 wt% or more and 10 wt% or less in terms of weight percent concentration, and the compatibilizer ratio is 10 wt% or more and 30 wt% or less in terms of weight percent concentration. It was also confirmed that the moldability and gas barrier properties of the inner layer body could be secured. Furthermore, when the proportion of the polypropylene resin is 30 wt% or more and 40 wt% or less in terms of weight percent concentration, and the proportion of the ethylene vinyl alcohol copolymer resin is 30 wt% or more and 40 wt% or less in terms of weight percent concentration It was also confirmed that the moldability and gas barrier properties of the inner layer body could be secured.

  On the other hand, as shown in Comparative Examples 5 and 6, even when the inner layer body is a blend material containing a polypropylene resin, an ethylene vinyl alcohol copolymer resin, a master batch for PP and a compatibilizer, the PP in the blend material It was found that when the ratio of the master batch for use and the compatibilizer was less than 20 wt%, the moldability and gas barrier properties of the inner layer could not be ensured.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, in the above-described embodiment, the case where the double container 1 is configured as a delamination container is shown. However, the outer layer body 2 and the inner layer body 3 may be formed separately and assembled together after each formation. Good.

  Moreover, in the said embodiment, although random polypropylene is used as a polypropylene which comprises the blend material of the inner layer body 3, you may make it use another polypropylene.

  Furthermore, in the above-described embodiment, a PP masterbatch mainly composed of a low-density polyethylene resin is used, and maleic acid-modified polypropylene is used as a compatibilizing agent. Various master batches and compatibilizers can be used.

  The ethylene vinyl alcohol copolymer resin is not limited to those having an ethylene content of 38 mol% or less, and various resins can be used.

DESCRIPTION OF SYMBOLS 1 Double container 2 Outer layer body 2a Mouth part 2b Trunk part 2c Male screw 3 Inner layer body 3a Storage part 4 Outside air introduction hole

Claims (8)

A double container having a volume-reducing and deformable inner layer body that contains contents and an outer layer body that contains the inner layer body inside,
The inner layer body is
Consists of a blend material formed by melting and kneading polypropylene resin, ethylene vinyl alcohol copolymer resin, PP masterbatch and compatibilizer,
The double container, wherein a ratio of the PP masterbatch and the compatibilizer in the blend material is 20 wt% or more and 35 wt% or less. The proportion of the polypropylene resin in the blend material is 30 wt% or more and 40 wt% or less,
The double container according to claim 1, wherein a proportion of the ethylene vinyl alcohol copolymer resin in the blend material is 30 wt% or more and 40 wt% or less. The proportion of the master batch for PP in the blend material is 3 wt% or more and 10 wt% or less,
The double container according to claim 1 or 2, wherein a ratio of the compatibilizer in the blend material is 20 wt% or more and 30 wt% or less.   The master batch for PP is a polymer whose main component is low-density polyethylene, modified with 0.01 to 2.00 wt% maleic anhydride, and whose terminal functional group is a hydroxyl group. 2. The double container according to item 1.   The double container according to any one of claims 1 to 4, wherein the compatibilizing agent is maleic acid-modified polyolefin.   The double container according to any one of claims 1 to 5, wherein the outer layer body is formed of a polyethylene terephthalate resin.   The double container of Claim 6 whose melting | fusing point of the said masterbatch for PP and the said compatibilizer is 100 degreeC or more, respectively.   The double container according to any one of claims 1 to 7, wherein the ethylene vinyl alcohol copolymer resin has an ethylene content of 38 mol% or less.

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