JP5929250B2 - Plastic container - Google Patents

Description

  The present invention relates to a plastic container suitable for containing seasonings such as salt and pepper, or powders such as powder.

  Conventionally, containers for containing powders such as seasonings have been required to be made of glass since transparency and water vapor barrier properties are required.

  However, recently, a resin container is desired for convenience of handling the container and consideration for the environment. However, resin containers are currently less transparent and have a water vapor barrier property than glass containers. If the transparency is poor, it becomes difficult to visually recognize the contents stored in the container. Further, if the water vapor barrier property is poor, when the powder is stored in a container, the influence of water vapor will affect the powder.

  For this reason, development of a resin container excellent in transparency and water vapor barrier properties is considered necessary.

  As a technical document filed prior to the present invention, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2009-248996) includes a core layer made of a gas barrier resin, and an inner layer and an outer layer made of a polyolefin resin. A container having excellent transparency, flexibility and rigidity is disclosed.

JP 2009-248996 A

  Since the container of Patent Document 1 has a core layer made of a gas barrier resin, it is excellent in gas (oxygen, carbon dioxide) barrier properties but is poor in water vapor barrier properties. For this reason, when powder is stored in the container of Patent Document 1, the influence of water vapor affects the powder. In addition, when the powder is stored in the container of Patent Document 1, static electricity is generated due to friction between the inner layer made of polyolefin resin and the powder, and the powder adheres to the inner layer, and the internal visibility of the container is poor. Become.

  This invention is made | formed in view of the said situation, and it aims at providing the plastic container excellent in transparency, water vapor | steam barrier property, and antistatic property in the plastic container which accommodates powder.

  In order to achieve this object, the present invention has the following features.

The plastic container according to the present invention is
A plastic container for containing powder,
An inner layer made of a resin containing an antistatic agent exposed inside the container ;
And a water vapor barrier layer made of a cyclic olefin-based resin , which is disposed outside the inner layer .

  According to the present invention, a plastic container excellent in transparency, water vapor barrier property and antistatic property can be obtained.

It is a figure which shows the structural example of the plastic container of this embodiment.

<Outline of plastic container 100>
First, an outline of the plastic container 100 of the present embodiment will be described with reference to FIG.
The plastic container 100 of the present embodiment is a plastic container 100 that contains the powder 101, and includes an inner layer 1 made of a resin containing an antistatic agent, a barrier layer made of a cyclic olefin resin (corresponding to the intermediate layer 2), It is characterized by providing. The plastic container 100 of this embodiment is excellent in antistatic property because the inner layer 1 contains an antistatic agent. In addition, since it is configured to have a barrier layer 2 made of a cyclic olefin resin, it is excellent in transparency and water vapor barrier properties. As a result, a plastic container 100 having excellent transparency, water vapor barrier properties, and antistatic properties can be obtained. Hereinafter, the plastic container 100 of the present embodiment will be described with reference to the accompanying drawings.

<Configuration example of plastic container 100>
First, a configuration example of the plastic container 100 of the present embodiment will be described with reference to FIG.

  The plastic container 100 according to the present embodiment is a plastic container 100 that contains a seasoning such as salt and pepper, or a powder 101 such as powder, and includes an inner layer 1, an intermediate layer 2, and an outer layer 3 as shown in FIG. It has a three-layer structure.

  The intermediate layer 2 is made of a resin having a water vapor barrier property. As the resin having a water vapor barrier property, a cyclic olefin-based resin can be suitably used since it has transparency and an excellent water vapor barrier property. The cyclic olefin-based resin is not particularly limited, and a cyclic olefin copolymer (COC), a cyclic olefin polymer (COP), or the like is applicable. Further, as the intermediate layer 2, a resin in which a cyclic olefin resin and a high density polyethylene resin (HDPE) are mixed can be used, and a container excellent in transparency and water vapor barrier properties can be obtained.

  Note that the intermediate layer 2 has a thickness in the range of 10 μm to 100 μm because the barrier property is lowered when the thickness of the intermediate layer 2 is too thin, and the impact resistance is lowered when the thickness is too thick. Is preferred.

  The inner layer 1 and the outer layer 3 are preferably composed of a resin having a light transmittance of 55% or more measured in accordance with JIS K7361-1, and having excellent transparency. Examples of the resin having excellent transparency include polyester resins and olefin resins. As the olefin-based resin, polypropylene (PP) to which a nucleating agent for improving transparency can be preferably used. Examples of the polyester resin include polyethylene terephthalate (PET, PET-G), polyethylene naphthalate (PEN), polycyclohexylenedimethylene terephthalate (PCT), and the like.

  Since the ethylene resin has poor adhesion to the intermediate layer 2, in order to improve the adhesion to the intermediate layer 2, the adhesive layers 4, 5 are provided between the inner and outer layers 1, 3 and the intermediate layer 2. It is necessary to add an adhesive to the inner and outer layers 1 and 3 and the intermediate layer 2. It should be noted that the adhesive constituting the adhesive layers 4 and 5 and the adhesive added to the inner and outer layers 1 and 3 and the intermediate layer 2 are not particularly limited, and known adhesives can be applied.

  The propylene-based resin can improve transparency by adding a nucleating agent. The nucleating agent for improving the transparency is not particularly limited as long as transparency is obtained, and a known nucleating agent can be added. In order to increase the light transmittance of the propylene resin alone, it is preferable to use a random copolymer resin. In order to provide heat resistance and impact resistance while improving the light transmittance, it is preferable to mix the block copolymer resin in the range of 15 to 45% by weight with respect to the random copolymer resin.

  Examples of the nucleating agent for improving transparency include sorbitol compounds, rosin compounds, benzoate compounds, and organic phosphate compounds. Moreover, it is also possible to add a styrene-type elastomer as an additive for improving transparency. By adding the styrene elastomer to the propylene resin, it is possible to improve the transparency of the propylene resin and improve the adhesiveness with the intermediate layer 2 composed of the cyclic olefin resin. As a result, it has a three-layer structure of inner layer 1, intermediate layer 2, and outer layer 3 as shown in FIG. 1 without interposing adhesive layers 4 and 5 between inner and outer layers 1, 3 and intermediate layer 2. can do. Further, without adding an adhesive to the inner and outer layers 1, 3 and the intermediate layer 2, a three-layer structure of an inner layer 1, an intermediate layer 2 and an outer layer 3 can be formed as shown in FIG.

  The styrene elastomer is preferably hydrogenated styrene butadiene rubber (HSBR), and finely dispersed in a propylene resin. In addition, the addition amount of a styrene-type elastomer is 1 to 50% with respect to a propylene-type resin, Preferably, it is 10 to 30%. If it exceeds 50%, the propylene resin becomes too soft, and the melting points of the inner and outer layers 1 and 3 become too low. On the other hand, if it is less than 1%, adhesion and transparency are insufficient. Therefore, when a propylene resin is used as the resin constituting the inner and outer layers 1 and 3 and a styrene elastomer is used as a nucleating agent, it is preferably added in a range of 1 to 50% with respect to the propylene resin. .

  Further, the inner layer 1 of the present embodiment is configured to contain an antistatic agent. By configuring the inner layer 1 to contain an antistatic agent, it is possible to prevent static electricity from being generated due to friction between the powder 101 housed in the plastic container 100 and the inner layer 1. Thereby, it is possible to prevent the powder 101 from adhering to the inner layer 1 due to static electricity. As a result, the internal visibility of the plastic container 100 can be improved.

  As the antistatic agent added to the inner layer 1, the antistatic agent migrates (bleeds out) to the surface of the base resin that constitutes the inner layer 1, as in the low molecular migration type, and its hydrophilic group adsorbs moisture in the air. However, it is different from the mechanism that develops antistatic properties by ionic conduction, and the antistatic properties are manifested by forming a network in the base resin of the ion conductive high molecular weight antistatic agent. Those are preferred. As this type of high molecular weight antistatic agent (permanent antistatic agent), those having a polyamide-based copolymer as a main component are preferable, and those having a polyether ester amide as a main component are more preferable.

  (I) Aminocarboxylic acid or lactam having 6 or more carbon atoms, or a diamine and dicarboxylic acid salt having 6 or more carbon atoms, which are constituents of polyetheresteramide, include ω-aminocaproic acid and ω-aminoenanthate. Acids, ω-aminocaprylic acid, ω-aminopergonic acid, ω-aminocapric acid and aminocarboxylic acids such as 11-aminoundecanoic acid, 12-aminodecanoic acid or lactams and hexamers such as caprolactam, enanthractam, capryllactam and laurolactam Diamine-dicarboxylic acid salts such as methylenediamine-adipate, hexamethylenediamine-sebacate and hexamethylenediamine-isophthalate are used, especially caprolactam, 12-aminododecanoic acid, hexamethylenediamine-adipic acid Salt is preferred It is needed.

  (Ii) Poly (alkylene oxide) glycol which is a constituent of polyetheresteramide includes polyethylene glycol, poly (1,2-propylene oxide) glycol, poly (1,3-propylene oxide) glycol, poly (tetramethylene) Oxide) glycol, poly (hexamethylene oxide) glycol, block or random copolymer of ethylene oxide and polypyrene oxide, block or random copolymer of ethylene oside and tetrahydrofuran, and the like are used. Among these, polyethylene glycol is particularly preferably used in terms of excellent antistatic properties. The number average molecular weight of the poly (alkylene oxide) glycol is used in the range of 200 to 6000, particularly 250 to 4000. If the number average molecular weight is less than 200, the resulting polyether ester amide has poor mechanical properties and the number average molecular weight When the value exceeds 6000, the antistatic property is insufficient, which is not preferable.

  (Iii) Dicarboxylic acids having 4 to 20 carbon atoms, which are constituents of polyetheresteramide, include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid Aromatic dicarboxylic acids such as diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid and sodium 3-sulfoisophthalate, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid and dicyclohexyl-4, Examples include alicyclic dicarboxylic acids such as 4'-dicarboxylic acids, and aliphatic dicarboxylic acids such as succinic acid, oxalic acid, adipic acid, sebacic acid and dodecanediic acid (decane dicarboxylic acid). Acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid and dodecanedioic acid , Preferably used in the color and physical properties viewpoint.

  (Ii) Poly (alkylene oxide) glycol and (iii) dicarboxylic acid are reacted at a molar ratio of 1: 1 in the reaction, but are usually supplied at different feed ratios depending on the type of dicarboxylic acid used. (Ii) Poly (alkylene oxide) glycol and (iii) dicarboxylic acid, which are constituents of polyether ester, are constituent units of polyether ester amide and are used in the range of 90 to 10% by weight, and more than 90% by weight In such a case, the mechanical properties of the polyetheresteramide are inferior, and if it is less than 10% by weight, the antistatic property of the resulting resin is inferior.

  The method for polymerizing the polyetheresteramide is not particularly limited. For example, (i) an aminocarboxylic acid or lactam and (iii) a dicarboxylic acid are reacted to form a polyamide prepolymer having carboxylic acid groups at both ends. ii) A method in which poly (alkylene oxide) glycol is reacted under vacuum, or each of the above compounds (i), (ii), and (iii) is charged into a reaction vessel and heated at high temperature in the presence or absence of water. A method in which a carboxylic acid-terminated polyamide prepolymer is produced by a pressure reaction and then polymerization is carried out under normal pressure or reduced pressure, or the compounds (i), (ii) and (iii) above are simultaneously reacted in a reaction vessel. The method of proceeding polymerization at a time under high vacuum after charging and mixing in the mixture can be used.

  The antistatic agent is preferably added in the range of 5 to 40% by weight with respect to the polyolefin resin constituting the inner layer 1. This is because if the amount of the antistatic agent added is too small, the antistatic property cannot be exerted, and if the amount of the antistatic agent added is too large, the mechanical properties (tensile properties) of the polyolefin resin constituting the inner layer. , Bending characteristics, impact strength, etc.).

  In addition, since the inner and outer layers 1 and 3 are too thin, the impact resistance is lowered if the inner and outer layers 1 and 3 are too thin, and the transparency is lowered if the thickness is too thick. It is preferably in the range of 900 μm.

  The plastic container 100 of the present embodiment has a laminated structure in which the intermediate layer 2 made of a cyclic olefin resin is sandwiched between inner and outer layers 1 and 3 made of a resin having a light transmittance of 55% or more and excellent in transparency. Therefore, it is excellent in transparency, barrier properties and impact resistance. In addition, since the inner layer 1 in contact with the powder 101 contains an antistatic agent, antistatic properties can be obtained. Therefore, the plastic container 100 of the present embodiment has inner and outer layers 1 and 3 made of a resin having a light transmittance of 55% or more, and an intermediate layer 2 having a water vapor barrier property, and is an inner layer in contact with the powder 101. By comprising 1 containing an antistatic agent, a plastic container 100 excellent in transparency, water vapor barrier property, antistatic property and impact resistance can be obtained.

  In the plastic container 100 described above, a layer (gas barrier layer) made of a gas barrier resin is provided between at least one of the inner layer 1 and the intermediate layer 2 and between the intermediate layer 2 and the outer layer 3. It is also possible. Thereby, the plastic container 100 excellent in gas (oxygen, carbon dioxide) barrier properties can be obtained. As the gas barrier resin constituting the gas barrier layer, any resin that can exhibit gas (oxygen, carbon dioxide) barrier properties can be used. For example, saponified ethylene / vinyl acetate copolymer Resins such as (EVOH), vinylidene chloride (PVDC), polyvinyl alcohol (PVA), and polyamide (PA) are applicable. It is also possible to provide a gas barrier layer as the outermost layer of the outer layer 3. In order to effectively exhibit gas barrier properties, it is preferable to provide a gas barrier layer between the intermediate layer 2 and the outer layer 3.

  The above-described embodiment is a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiment alone, and various modifications are made without departing from the gist of the present invention. Implementation is possible. For example, in the above-described embodiment, the barrier layer is described as the intermediate layer 2, but the two-layer structure of the inner layer 1 containing the antistatic agent and the outer layer 3 made of a resin having a barrier property is not limited to the three-layer structure. You may comprise.

100 Plastic container 101 Powder 1 Inner layer 2 Intermediate layer 3 Outer layer

Claims (7)

A plastic container for containing powder,
An inner layer made of a resin containing an antistatic agent exposed inside the container ;
A plastic container comprising: a water vapor barrier layer made of a cyclic olefin-based resin , disposed outside the inner layer .   The plastic container according to claim 1, wherein the light transmittance is 55% or more.   The plastic container according to claim 1, wherein the antistatic agent is a polyether ester amide. Comprising an outer layer disposed outside the water vapor barrier layer;
The plastic container according to any one of claims 1 to 3, wherein the inner layer and the outer layer are made of a propylene-based resin having a nucleating agent. Comprising an outer layer disposed outside the water vapor barrier layer;
The plastic container according to any one of claims 1 to 3, wherein the inner layer and the outer layer are made of a polyester resin. The plastic container according to any one of claims 1 to 5, wherein the water vapor barrier layer is made of a mixed resin of the cyclic olefin resin and the high density polyethylene resin.   The plastic container according to claim 1, further comprising a layer made of a gas barrier resin.

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