JP5050679B2 - Method for producing gas barrier injection molded container - Google Patents

Description

The present invention relates to a method for producing a thin gas barrier injection-molded container in which a side portion of a gas barrier injection-molded container is formed by in-molding, and then a polyolefin resin and a gas barrier resin are co-injected to form a container bottom. About.

  Conventionally, there is a cup-shaped container provided with a gas barrier property so that the contents are not adversely affected by oxygen in the air, and it is frequently used as a food or other container.

  For example, in a multilayer container including a polyglycolic acid layer and a thermoplastic polyester resin layer, an intermediate layer composed of at least one polyglycolic acid layer is embedded in the thermoplastic resin layer on the container body and the bottom. There is a cup-shaped multilayer container (Patent Document 1). PET is used as the thermoplastic polyester resin layer, a bottomed multilayer preform is molded by co-injection, and this is biaxially stretch blow molded to produce a multilayer container. EVOH is close to the melting point and thermal decomposition temperature and has a high melt viscosity. Therefore, in view of the difficulty of co-injection stretch blow molding in combination with PET, a polyglycolic acid layer is used instead of EVOH as a gas barrier resin. It is what was used. The container is suitable for beverages and food containers such as fruit juice drinks containing carbon dioxide, lactic acid bacteria drinks, beer, wine, soy sauce, sauces, jams, jellies, soups, salad oils, and the like.

  The resin constituting the outermost layer and the innermost layer is a thermoplastic polyester resin, has at least one gas barrier resin layer, can impart oxygen scavenging properties to the gas barrier resin, and whiten the gas barrier resin. There is also a multilayer structure containing an additive that can be prevented (Patent Document 2). In Examples, a parison is molded using PET as a thermoplastic polyester resin and polyamide MXD6 as a gas barrier resin, and the parison is biaxially stretch blow molded to produce a bottle having a capacity of 720 ml.

  On the other hand, as a multilayer molded container in which a gas barrier resin is laminated on a polyolefin resin or the like, the thermoplastic resin (1) layer / the resin layer containing the oxygen-supplementing resin / the thermoplastic resin (2) layer is laminated in this order from the inner layer to the outer layer. However, a plastic multilayer molded container manufactured by vacuum molding is also disclosed (Patent Document 3). In the example, a multilayer sheet is formed by laminating each layer with a urethane-based adhesive, and this is vacuum-formed to produce a substantially cylindrical container having a diameter of 7 cm and a capacity of 80 cc.

  There is also a container formed by injection molding of a synthetic resin, and a cup-shaped container in which a gas barrier label is integrated inside or outside a container side part (Patent Document 4). A gas barrier label is attached to the mold of the cup-shaped container, and the first synthetic resin is injected by in-molding so as to be integrated with the film to form the side of the container, and then the first synthetic resin injected earlier is formed. A second synthetic resin having a gas barrier property is injected therein to form the bottom wall of the cup-shaped container. Examples of the first synthetic resin include polypropylene resin and polyethylene, examples of the second synthetic resin include EVOH, MXD6 nylon, and PVDC, and the thickness of the bottom portion is 0.5 to 1.5 mm.

  Similarly, there is a cup-shaped container formed by injection molding of a synthetic resin and integrated with gas barrier labels on the bottom and side of the container (Patent Document 5). In order to integrate the gas barrier label on the bottom, a cup-shaped container having no irregularities on the inner and outer surfaces of the bottom is formed, and the gas barrier label is bonded to the bottom of the cup-shaped container with an adhesive. That's it.

  Furthermore, devices for multilayer injection molding are also known. There is also an apparatus for forming a preform having an intermediate layer of a barrier material between an inner layer and an outer layer of PET by a multi-cavity valve gate type three-layer injection molding method (Patent Document 6). Two types of resin, PET and barrier material, are injected from the valve gate into the mold by pushing the movable pin. The barrier material is injected through the annular passage of the heating nozzle, and at the same time, PET is melted in the center of the valve pin. By injecting through the material bore, the cycle time can be reduced and the PET inner layer can be thickened.

  There is also a multi-plate molding apparatus for injection molding of molded products made of PET and suitable for blow stretching (Patent Document 7). This is an apparatus for forming a preform composed of PET and an intermediate layer. In view of the fact that PET reacts sensitively to pressure fluctuation and shearing force, two types of resin, PET and intermediate layer, are transferred from the valve gate to the movable pin. It is injected into the mold by extrusion and is equipped with a compressed air operated valve device for taking out or closing different materials by the movable pin, and according to this device, a multilayer preform with uniform density is formed It can be done.

Furthermore, there is also a hot runner mold for injection molding having a mechanism for instantaneously stopping the back flow of the resin corresponding to the injection pattern (Patent Document 8). A device that forms preforms from two different types of resins, and when the inner and outer layer resins are supplied from the resin supply port and then the intermediate layer resin is supplied from the resin supply port, the mold is turned off when the supply of the intermediate layer resin is stopped. Since the pressure of the line for supplying the inner layer resin decreases, the inner and outer layer resin being injected enters the flow path of the intermediate layer resin from the junction in the multiple nozzle. The check valve is moved instantaneously by the pressure to close the flow path in a seal shape and function as a check valve, which can suppress the intrusion amount of the resin for the inner and outer layers to a very small amount. It is said that the variation in the filling amount to the mold cavity can be reduced.
JP 2003-136657 A JP 2003-251775 A JP 2001-55216 A JP 2006-56559 A JP 2006-96390 A JP-T-2002-529272 Japanese Patent Laid-Open No. 7-164512 JP 2004-330672 A

  The gas-barrier cup-shaped container is a small container that dislikes contact with easily oxidizable substances, oxygen and air as containers for various beverages such as soup and fruit juice, seasonings such as sauce and soy sauce, and confectionery such as jelly and ice cream. It is a container that is used in storage containers for precision instrument parts and is consumed in large quantities. Therefore, it is desired that it can be manufactured in large quantities by a simple process. As a method for producing such a container suitable for mass production, there is an injection molding, which has excellent characteristics such as that a product having a stable dimension can be produced, and an efficient molding can be performed with little need for post-finishing. If a gas-barrier cup-shaped container can be manufactured by co-injection molding of the base resin and the gas-barrier resin, it is easy to manufacture and it is also possible to form a deep container compared to vacuum molding, There is an advantage that a plurality can be manufactured at the same time.

  However, the multilayer containers described in Patent Document 1 and Patent Document 2 are manufactured by manufacturing a preform by co-injection molding and stretching and blowing the preform. That is, it is only a preform that can be manufactured by co-injection molding, and in order to obtain a product, a process of stretching and blowing the preform is necessary, and the production efficiency is poor. In addition, the cup-shaped container preferably has excellent mechanical strength, heat resistance, impact resistance, and mechanical strength, and there are polyolefin resins as resins having such characteristics. The multilayer container described in Document 2 uses PET as a thermoplastic resin, and there is no disclosure regarding polyolefin. Note that the preform has a thick layer and cannot be used directly as a container.

  On the other hand, in Patent Document 3, a container including a polyolefin resin layer is manufactured, but a container is prepared by vacuum forming after a laminated film containing a polyolefin resin is formed in advance. , At least two steps of vacuum formation are required. Note that it is difficult to manufacture a deep container with high accuracy by vacuum forming. In addition, in the case of vacuum forming, the gas barrier resin is exposed from the end surface because the container end is cut after the forming. When the gas barrier resin is a hydrophilic resin such as EVOH, when performing retort sterilization in which water is immersed in water at 120 ° C. for about 30 minutes, water penetrates from the gas barrier resin layer on the end surface during use of the container, and the multilayer structure May be destroyed, and water may permeate the container wall and impair the gas barrier properties of EVOH.

  Furthermore, Patent Document 5 is suitable for manufacturing a container having a thin wall thickness by in-mold molding using a cavity equipped with a gas barrier label, but the bottom of the container adheres the gas barrier label after molding. There are many steps and the operation is complicated. Patent Document 4 injects a first synthetic resin and a second synthetic resin having gas barrier properties to form a bottom wall of a cup-shaped container having a thickness of 0.5 to 1.5 mm, but the bottom wall is thin. Therefore, there is a case where the inner second synthetic resin constituting this part may come out to the surface side from a part of the first synthetic resin enclosing it, and a complete sandwich structure may not be obtained. This indicates the difficulty in forming a multilayer structure.

  In addition, Patent Document 6, Patent Document 7, and Patent Document 8 are all intended to form a preform for PET as a base resin, and there is a description regarding multilayer injection molding using a polyolefin resin. do not do.

In view of the above situation, the present invention is, heat resistance, a process for the preparation of the gas barrier injection formation vessel which is excellent in mechanical strength, using a specific co-injection molding apparatus, the container side and in-mold molding, the container It is an object of the present invention to provide a method for producing a gas barrier injection molded container having a bottom part co-injection-molded with a polyolefin resin and a gas barrier resin to form a multilayer structure of two types and three layers.

As a result of examining the manufacturing method of a container having gas barrier properties in detail, the present inventor attached a gas barrier property label to the cavity, formed a side wall of the container by in-molding a polyolefin resin by a valve gate method, When the container bottom is formed by co-injection of a polyolefin resin and a gas barrier resin, a container bottom having a multilayer structure of two types and three layers can be formed using a conventional apparatus. After injecting the resin, the resin pressure is kept as it is for a predetermined time, and after that, when the cavity is cooled, polyolefin resin, gas barrier resin and polyolefin resin are sequentially laminated from the outer layer to the inner layer at the bottom of the container. Excellent gas-barrier resin adhesion and gas-barrier shot without delamination It found that the formation vessel may be prepared, thereby completing the present invention.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the gas barrier property injection molding container which is excellent in mechanical strength, heat resistance, impact resistance, and gas barrier property can be provided.

The method for producing a gas barrier injection-molded container of the present invention can provide a container having a thin container thickness of 0.5 to 1.0 mm.

  The container manufacturing method of the present invention is a valve gate method in which at least the bottom of the container is formed by co-injection molding, is excellent in dimensional accuracy, can be manufactured in a small number of steps, and the injection of resin can be controlled in a short time. A container suitable for mass consumption that can be produced in large quantities can be provided.

The gas barrier injection molded container produced by the present invention has a gas barrier label and polyolefin resin laminated sequentially from the outer side of the container side, and a polyolefin resin, gas barrier resin and polyolefin resin laminated sequentially from the outer surface of the container bottom. A gas barrier injection molded container,
The container side is formed by injection molding the polyolefin resin into a cavity fitted with the gas barrier label,
The container bottom part is characterized by that it will be formed by co-injection molding and the gas barrier resin and the polyolefin resin, a gas barrier injection formation vessel.

The gas barrier resin is preferably at least one resin selected from the group consisting of saponified ethylene-vinyl alcohol copolymer (EVOH), polyamide and polyxylylenediamine dipamide, and the gas barrier resin However , when it consists of EVOH, it is preferable that MFR in the temperature of 210 degreeC is 10-30 g / 10min, and / or an ethylene copolymerization ratio is 30-40 mol%. Although there is no limitation in the shape of the container, it may have a bottom part, a side part arranged on the outer periphery of the bottom part, and a flange part provided on the outer periphery of the side part. The gas barrier resin may not be present in the flange portion. Hereinafter, the present invention will be described in detail with reference to the drawings.

(1) Gas Barrier Injection Molding Container As shown in FIG. 1, the gas barrier injection molding container produced by the present invention has a bottom portion (10) and a side portion (20) disposed on the outer periphery of the bottom portion. And preferably, as shown in FIG. 1, it has the flange part (30) provided in the outer periphery of the said side part. A thread bottom (13) may be formed at the bottom. Generally, an injection gate for injection molding is formed at the center of the bottom of the container.

The gas barrier injection-molded container manufactured by the present invention forms a container side part by in-mold molding of a polyolefin resin into a cavity equipped with a gas barrier label (70), and then the polyolefin resin and the gas barrier resin. preparative by co-injection from the injection gate of a container obtained by forming a container bottom, the polyolefin resin (50) from the vessel bottom outer layer toward the inner layer, the gas barrier resin (40) and the polyolefin resin (50 ' ) that Do from the. The gas barrier resin (40) may be present at the container bottom (10), but may be present at the lower end of the container side as shown in FIG. Moreover, when it has a flange part (30) as shown in FIG. 1, the gas barrier property label (70) does not need to exist in a flange part (30). As shown in FIG. 2, a gas barrier property is imparted to the flange portion (30) by adhering a lid portion (60) made of a gas barrier label to the upper portion of the flange portion (30) via an adhesive layer (63). This is because the gas barrier property of the entire container having such a lid can be secured.

The gas barrier injection molded container produced by the present invention is formed by co-injecting at least the bottom of the container with a polyolefin-based resin and a gas barrier resin, but limited to co-injection molding, This is because two types of polyolefin resin and gas barrier resin can be simultaneously injected into the container bottom mold to form a multilayer structure of two types and three layers in a short time. Moreover, according to the specific co-injection, as shown in FIG. 1, the thickness (T2) of the polyolefin resin outer layer (50) at the bottom of the container is thicker than the thickness (T1) of the polyolefin resin inner layer (50 ′). (T2> T1), it is possible to form a stable multilayer structure in the gate part for injection and avoid exposure of the gas barrier resin, and to enhance the gas barrier property of the entire container and the mechanical strength of the container bottom. . Preferably, T2> T1, the outer layer (T2) is 0.4 to 0.75 mm, and the inner layer (T1) is 0.03 to 0.3 mm.

Gas barrier injection molding container produced according to the present invention, the average container thickness of the bottom portion (T) is 0.5 to 1.0 mm, preferably Ru can be 0.6～0.9Mm. Na you may not gas barrier property label is present on the flange portion in the case of having a flange portion (30) as described above. Further, the gas barrier injection molded containers produced by the present invention, the ratio of the gas barrier resin to the total of the polyolefin resin and the gas barrier resin constituting the container bottom, Ru can be 5 to 10 wt% . In the gas barrier injection molded container produced by the present invention , since the gas barrier resin is laminated with a uniform thickness, even when the gas barrier resin is laminated extremely thin at the above ratio, sufficient gas barrier properties can be secured. . In addition, you may laminate | stack another layer on a container outer layer and / or an inner layer.

  As the polyolefin resin constituting the container side and the container bottom, polyethylene, polypropylene, polybutylene, polystyrene, and the like can be suitably used. In particular, the polypropylene resin is preferable in terms of excellent mechanical strength, heat resistance, and impact resistance. The polypropylene resin may be a crystalline polypropylene resin mainly having an isotactic or syndiotactic structure, and has a wide structure such as a random type including a homotype or a comonomer, or a block type by multistage polymerization. Can also be suitably used. The polypropylene resin can employ multi-stage polymerization by gas phase polymerization method, bulk polymerization method, solvent polymerization method and any combination thereof. The polypropylene resin is preferably a polypropylene resin having a melting point of 80 to 176 ° C. and a crystal melting heat of 30 to 120 J / g, and a melting point of 120 to 176, from the viewpoint of enhancing the heat resistance of the resulting gas barrier injection molding container. More preferred is a polypropylene resin having a crystal melting heat of 60 to 120 J / g. Here, the melting point and the heat of crystal fusion are numerical values measured according to JIS-K-7121 and JIS-K-7122, respectively.

  As a method for producing a polypropylene-based resin, generally, a Ziegler-Natta type catalyst using a combination of a so-called titanium-containing solid transition metal component and an organic metal component, a transition metal of Groups 4 to 6 of the periodic table Slurry polymerization, gas phase polymerization, using a catalyst comprising a compound as an essential component or a metallocene catalyst having a transition metal compound of Groups 4 to 6 of the periodic table having at least one cyclopentadienyl skeleton as an essential component. A bulk polymer, solution polymerization, or the like or a combination of these methods is used in one or more stages to obtain a homopolymer by homopolymerizing propylene or selected from propylene and other olefins having 2 to 12 carbon atoms A method of obtaining a copolymer by copolymerizing one or more kinds of olefins in one or more stages can be mentioned. Further, a combination of homopolymerization and copolymerization in multiple stages is also possible.

  Moreover, as polyolefin resin used by this invention, MFR is 10-90 g / 10min at the temperature of 190 degreeC, More preferably, the thing of 30-70 g / 10min is suitable. Commercially available products can be used as the polyolefin resin used in the present invention.

  In the present invention, the polypropylene resin may contain a modified resin in which a polar group is introduced into polyolefin. Polyolefins are not polar and may have poor adhesion to gas barrier resins. Therefore, in order to ensure adhesion with the gas barrier resin, a two-layer / three-layer gas barrier injection-molded container without delamination can be obtained by mixing a modified resin into which a polar group has been introduced. Such a modified resin may be a commercially available product, for example, trade name “Modic” manufactured by Mitsubishi Chemical Corporation, trade name “Admer” manufactured by Mitsui Chemicals. Such a modified resin may be mixed in a polyolefin resin in the range of 0 to 50% by mass.

Moreover, as a gas barrier resin, ethylene - vinyl alcohol copolymer saponified (EVOH), nylon 6, nylon 66, from the group consisting of poly-xylylenediamine dipalmitoyl bromide such as polyamide and MXD6 such as nylon 12 is at least one resin selected, and more preferably EVOH, poly xylylenediamine dipalmitoyl bromide. This is because the gas barrier property is excellent. Especially, it is EVOH whose MFR in the temperature of 210 degreeC is 10-30 g / 10min, Preferably it is 15-25 g / 10min. A melt flow rate (MFR) is based on the method prescribed | regulated to JIS-K-7203, measurement temperature is 210 degreeC and a commercial item can also be used in this invention measured as a load 2.16kg. This is because if the MFR is in the above range, a multilayer structure can be formed with the polyolefin resin by co-injection molding. In the present invention, EVOH has an ethylene copolymerization ratio of 30 to 40 mol%. This is because it is possible to obtain a co-injection molding container having excellent especially gas barrier properties in the above-mentioned range.

  The polyolefin resin and gas barrier resin used in the present invention have various additional components such as an anti-aging agent, an antioxidant, an ozone degradation inhibitor, and an ultraviolet absorber within the range that does not impair the purpose of use of the injection molded container. Agent, light stabilizer, antistatic agent, slip agent, internal release agent, colorant, dispersant, anti-blocking agent, lubricant, anti-fogging agent, filler, softener, flame retardant, high-frequency processing aid, glitter filler A nucleating agent, a plasticizer, an antibacterial agent, and the like can be appropriately blended. and so on.

A conventionally known gas barrier label can be used as the gas barrier label constituting the side portion of the gas barrier injection-molded container produced according to the present invention. For example, it is a base film layer including at least a gas barrier layer.

  As a base film layer, as a base film, polyolefin resin, such as polyethylene resin, polypropylene resin, and cyclic polyolefin resin, fluorine resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), Acrylonitrile-butadiene-styrene copolymer (ABS resin), fluorine resin, poly (meth) acrylic resin, polycarbonate resin, polyester resin such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various nylons, Polyimide resin, polyamideimide resin, polyaryl phthalate resin, silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal tree , And the like cellulose resin, Poriakuriro nitrile resins. In particular, a film of a polypropylene resin, a polyester resin, or a polyamide resin is preferable.

  The gas barrier layer includes an aluminum foil and a vapor deposition layer of metal or metal oxide. A film in which a metal or metal oxide vapor deposition layer is previously formed on the base film may be used as the base film layer and the gas barrier layer.

  The gas barrier label may contain a UV protection layer or a UV protection layer. Examples of UV inhibitors include polysalicylic acid esters, benzophenones, benzotriazoles, and acrylonitrile UV absorbers. As UV protection layers, the above UV absorbers are unstretched such as polyethylene, polypropylene, polyethylene terephthalate, and nylon films. Or the film contained in the stretched plastic film can be illustrated.

  Furthermore, the gas barrier label may be provided with a printing base material layer or a surface protective layer. As the surface protective layer, a film of polyethylene, polypropylene, polyethylene terephthalate or the like can be used.

  Further, the gas barrier label may have a heat seal layer. Examples of the heat seal layer include those made of a heat-adhesive material that can be softened and melted at 130 ° C. or lower and bonded to the side of the container. Examples of such heat-adhesive materials include (a) low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-α / olefin copolymer polymerized using a metallocene catalyst, polypropylene, Ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylic acid copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer A polymer, a polyolefin resin such as methylpentene polymer, polyethylene or polypropylene, modified with acrylic acid, methacrylic acid, maleic anhydride, fumaric acid or other unsaturated carboxylic acid, poly (meth) acrylic resin, Thermoplastic polyester tree , One or a plurality of thermoplastic polyamide resins, (b) unstretched or stretched plastic film such as polyethylene, polypropylene, polyethylene terephthalate, etc. having heat sealability, (c) ethylene-vinyl acetate copolymer A hot-melt layer containing or a heat sealable layer containing (d) an ethylene-vinyl acetate copolymer can be applied.

  The gas barrier label can be formed by dry-laminating each layer through an adhesive or by coextrusion of a part or all of the layer.

  In addition, it is composed of an easily peelable label that can be peeled from the biaxially stretched blow molded product body by adding an inorganic filler such as silicone, microcrystalline wax, calcium carbonate, etc. to the adhesive layer of the label to form a weakly adhesive layer can do. Since the label of this form can be peeled from the container main body, the container main body can be recycled after the label for forming the in-mold label is peeled from the container main body when the container is discarded.

  As such a gas barrier label, (i) stretched polypropylene film (substrate layer for printing) (30 μm) / polyethylene terephthalate (12 μm) / silicon oxide-deposited stretched polyethylene terephthalate film (gas barrier layer) (12 μm) / ethylene-vinyl acetate Stretched polypropylene film (heat seal layer) (30 μm) having a heat seal layer containing a copolymer, (ii) polyethylene terephthalate film (12 μm) / silicon oxide-deposited polyethylene terephthalate film (gas barrier layer) (12 μm) / ethylene-vinyl acetate Heat sealant layer (coating layer) containing copolymer (50 μm), (iii) Stretched polypropylene film (substrate layer for printing) (25 μm) / Aluminum foil (gas barrier layer) (15 μm) / ethylene-vinyl acetate (1) Stretched polypropylene film (25 μm) having heat-sealing properties including a copolymer, (iv) Stretched polypropylene film (substrate layer for printing) (25 μm) / silicon oxide-deposited polyethylene terephthalate film (12 μm) (gas barrier layer) / ethylene -Stretched polyethylene terephthalate film (heat seal layer) (25 μm) having a heat seal layer containing a vinyl acetate copolymer, (v) Stretched polypropylene film (25 μm) / Polyethylene terephthalate film (substrate layer for printing) (12 μm) / Silicon oxide vapor-deposited polyethylene terephthalate film (gas barrier layer) (12 μm) / stretched polypropylene film (heat seal layer) (25 μm) having heat sealability containing ethylene-vinyl acetate copolymer (vi) stretched polypropylene film Rum (printing substrate layer) (25 μm) / silicon oxide vapor-deposited stretched polyethylene terephthalate film (gas barrier layer) (12 μm) / ethylene methacrylic acid copolymer (heat seal layer) (25 μm), (vii) stretched polypropylene film (printing) Substrate layer) (25 μm) / silicon oxide vapor-deposited stretched polyethylene terephthalate film (gas barrier layer) (12 μm) / ethylene acrylic acid copolymer (heat seal layer) (25 μm), (viii) stretched polypropylene film (printing substrate) Layer) (25 μm) / silicon oxide-deposited stretched polyethylene terephthalate film (gas barrier layer) (12 μm) / hot melt agent layer (heat seal layer) containing ethylene vinyl acetate copolymer (50 μm), (ix) stretched polypropylene film (60 μm) ) / Ethylene vinyl acetate Hot melt agent layer (heat seal layer) (25 μm) containing copolymer, (x) stretched polypropylene film (60 μm) / hot melt agent layer (heat seal layer) containing ethylene vinyl acetate copolymer (25 μm), ( xi) Structures such as stretched polypropylene film (30 μm) / inorganic vapor-deposited polyethylene terephthalate film (12 μm) / stretched polypropylene film (30 μm) can be exemplified. In addition, in the said structure, even if it is a structure in which a heat seal layer exists, it can be used as a gas-barrier label in this case with the label structure except a heat seal layer.

  The gas barrier label used in the present invention can be used as a transparent label as long as a vapor deposition layer of an inorganic oxide is formed on a base film and the base film is laminated on the vapor deposition layer. In addition, as the vapor deposition film of the inorganic oxide, for example, a chemical vapor deposition method, a physical vapor deposition method, or a combination of these, a single layer film composed of one layer of the vapor deposition film of the inorganic oxide, or two or more layers is used. It can be manufactured by forming a multilayer film or a composite film. The chemical vapor deposition method may be any of chemical vapor deposition methods such as plasma chemical vapor deposition, low temperature plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. Specifically, on one surface of the base film layer, an evaporation monomer gas such as an organosilicon compound or aluminum oxide is used as a raw material, and an inert gas such as argon gas or helium gas is used as a carrier gas. Further, a vapor deposition film of an inorganic oxide such as silicon oxide can be formed by using a low temperature plasma chemical vapor deposition method using an oxygen gas or the like as an oxygen supply gas and using a low temperature plasma generator or the like.

  On the other hand, a gas barrier label in which an aluminum foil is bonded to a base film becomes an opaque label and can be suitably used. In the case of having an aluminum foil, light shielding properties as well as gas barrier properties can be ensured. For example, a gas barrier label having a layer structure of stretched polypropylene film (30 μm) / polyethylene terephthalate film (12 μm) / aluminum foil (7 μm) / stretched polypropylene film (30 μm) can be exemplified.

The gas barrier injection-molded container produced according to the present invention has an oxygen permeability of 0.005 to 0.05 cc / pg · day · atm due to the above configuration. In addition, let oxygen permeability be the value measured by the method described in the Example mentioned later.

(2) Method for Producing Gas Barrier Injection Molding Container The gas barrier injection molding container has a gas barrier label attached to a cavity, and a polyolefin resin is injected by in-mold to form a container side portion. The manufacturing method is not particularly limited as long as the bottom of the container is molded by co-injection with a gas barrier resin. However, it is preferable to manufacture by a valve gate system having a specific structure because a container having a multilayer structure having a uniform and excellent adhesive property can be formed in a short time. That is, the present invention is the container side is the outer surface is laminated gas barrier label and a polyolefin resin sequentially, the container bottom from the outer surface polyolefin resin and the gas barrier resin and a polyolefin resin is sequentially laminated gas barrier injection formation vessel A manufacturing method,
An injection gate, a polyolefin resin supply path extending from the injection gate, a gas barrier resin supply path extending from the polyolefin resin supply path, the polyolefin resin supply path, and a gas barrier resin supply Using a valve gate type multi-layer injection molding device having a movable pin inscribed in the road and controlling the resin supply,
After mounting the gas barrier label in the cavity, the movable pin is detached from the polyolefin resin supply path to inject the polyolefin resin to form the container side part,
The movable pin is separated from the polyolefin resin supply path and the gas barrier resin supply path to co-inject the polyolefin resin and the gas barrier resin, and then the movable pin is inserted into the gas barrier resin supply path. A method for producing a gas barrier injection-molded container, wherein the container bottom is formed by injecting only the polyolefin resin in contact therewith.

A container is formed by injecting a polyolefin resin from an injection gate into a cavity equipped with a gas barrier label to form a container side, co-injecting the polyolefin resin and the gas barrier resin, and then injecting the polyolefin resin. It can be manufactured by forming the bottom. By performing the pressure keeping to hold the resin pressure after the injection and filling the resin into the cavity, a polyolefin outer layer of the bottom portion toward the inner layer resin, the uniform thickness the gas barrier resin Contact and polyolefin resin A gas barrier injection-molded container which is laminated and has a polyolefin resin outer layer at the bottom of the container thicker than the polyolefin resin inner layer can be produced.

A gas barrier injection molding container manufactured by the present invention includes an injection gate, a polyolefin resin supply path extending from the injection gate, and a gas barrier resin supply path extending from the polyolefin resin supply path. And a valve gate type multi-layer injection molding apparatus having a polyolefin resin supply path and a movable pin that is inscribed in the gas barrier resin supply path and controls the resin supply. According to the above apparatus, since the injection and stop of the molten resin can be controlled from the injection gate by moving the movable pin, the resin supply can be controlled in a short time, suitable for mass production, and the entire bottom surface of the container This is because a polyolefin-based resin, a gas barrier resin, and a polyolefin-based resin are sequentially laminated from the outer layer to the inner layer, and a gas barrier injection-molded container having a thicker outer layer than the inner layer can be manufactured. An example of such a co-injection molding apparatus will be described with reference to FIG.

  The co-injection molding apparatus suitably used in the present invention comprises a polyolefin resin supply path (110) in which a plasticized polyolefin resin and a gas barrier resin are extended from an injection gate (130), and a polyolefin resin. It is injected from the injection gate (130) through the gas barrier resin supply passage (120) extending to the resin supply passage (110). The polyolefin resin and the gas barrier resin are plasticized by a resin plasticizer (not shown), and then passed through the polyolefin resin supply pipe (113) and the gas barrier resin supply pipe (123), and then the polyolefin resin supply path (110). The gas barrier resin supply path (120) is supplied.

  The shape of the polyolefin resin supply path (110) and the gas barrier resin supply path (120) is not limited, but in FIG. 3, the gas barrier resin supply path (120) is formed in an annular shape on the outer periphery of the movable pin (160). Further, a polyolefin resin supply path (110) is annularly arranged on the outer periphery thereof. FIG. 9 is a schematic sectional view taken along line AA ′ of FIG. A movable pin (160) is inserted in the center of the gas barrier resin supply passage (120), and the polyolefin resin supply passage (110) is arranged in an annular shape so as to go around the outer periphery of the gas barrier resin supply passage (120). Yes.

  The movable pin (160) can be fitted to the injection gate (130), and can stop the resin supply by being inscribed in the polyolefin resin supply path (110) or the gas barrier resin supply path (120). It is a structure that can supply resin by leaving the road. The movement of the movable pin (160) can be controlled by a pneumatic pump or the like (not shown). FIG. 10 shows an injection gate (130), a polyolefin resin supply channel (110) extending from the injection gate, and a gas barrier resin supply channel (110) extending from the polyolefin resin supply channel (110). 120). When the tip position of the movable pin (160) is at P1, no resin is supplied, and when the tip position is at P2, only the polyolefin resin is supplied from the polyolefin resin supply path (110). . When the tip position is P3, the gas barrier resin passes through the gas barrier resin supply path (120) and the polyolefin resin supply path (110) to the injection gate (130), and the polyolefin resin supply path ( 110) from the injection gate (130) together with the polyolefin-based resin facing the injection gate (130). The cross-sectional area of each supply path can be appropriately selected in accordance with the resin supply amount, injection pressure, and the like for each layer of the multilayer molded body. According to the above configuration, since the start and stop of the injection of the two types of resin can be controlled in a short time by the vertical movement of the movable pin (160), the production efficiency can be improved.

  In addition, since the pneumatic device for mounting the gas barrier label into the cavity, plasticizing the resin, and injecting the resin can be understood in the same manner as a conventionally known device, a polyolefin resin and a gas barrier resin are described below. The injection gate (130) is opened and closed by the vertical movement of the movable pin (160), the co-injection state of the polyolefin resin and the gas barrier resin, the movement of the movable pin (160) and the resin The relationship with injection will be described with reference to FIGS.

  FIG. 4 shows a state in which the tip of the movable pin (160) is fitted into the injection gate (130), and no resin is injected from the injection gate (130) into the cavity (150). The cavity (150) is preliminarily fitted with a gas barrier label (70) and cooled to a solidification temperature, usually 5 to 30 ° C., more preferably 15 to 20 ° C.

  In this state, when the movable pin (160) is moved upward while applying pressure to the polyolefin resin in the polyolefin resin supply path (110), the movable pin is detached from the polyolefin resin supply path (110). As shown in FIG. 5, only the polyolefin resin is injected from the polyolefin resin supply path (110). Since the cavity (150) is cooled to a temperature of 5 to 30 ° C., the polyolefin resin injected into the cavity (150) is brought into contact with the inner wall of the cavity (150) to solidify, and the cavity (150 150), a temperature gradient of the polyolefin resin is formed from the inner wall toward the inside of the resin. In addition, the injection temperature of polyolefin resin is 150-300 degreeC, More preferably, it is 200-250 degreeC. The polyolefin resin used in the present invention has an MFR of 10 to 90 g / 10 min at a temperature of 190 ° C., and since it has excellent fluidity, the injected resin is a cavity having an average container thickness of 0.5 to 1.0 mm. The inside of (150) can be advanced over a length of 60 to 250 mm, and the container tip and container side can be filled with a polyolefin resin.

  Next, while applying pressure to the resin in the gas barrier resin supply path (120), the movable pin (160) is further moved upward in the apparatus, and the movable pin is moved to the polyolefin resin supply path (110) and the gas barrier resin supply path (120. 6), as shown in FIG. 6, the gas barrier resin is supplied to the approximate center of the polyolefin resin, and the gas barrier resin is present at the approximate center of the polyolefin resin. It is injected. The polyolefin resin is divided into two layers by the gas barrier resin, and the polyolefin resin forms an inner layer (50 ') and an outer layer (50) at the bottom of the container in the cavity (150).

The time for moving the movable pin (160) upward and starting the injection of the gas barrier resin depends on the injection pressure and injection speed of the polyolefin resin, the capacity of the cavity (150), the shape of the cavity (150), etc. It can be selected appropriately. Since the gas barrier resin forms the bottom of the container, it is generally after the polyolefin resin is supplied to the cavity (150) in an amount that constitutes the side of the container. When the gas barrier resin is EVOH, the injection temperature of the gas barrier resin is 190 to 240 ° C., more preferably 210 to 230 ° C. EVOH has an MFR of 10 to 30 g / 10 min at 210 ° C., and at the above injection temperature, the highest temperature portion of the temperature gradient of the polyolefin resin injected into the cavity (150), that is, the most fluidity. This is because the gas barrier resin is formed at a high portion, and a multilayer structure having a uniform thickness is formed. In detail, since the polyolefin resin in the cavity (150) forms a concentration gradient, the gas barrier resin is injected even if the MFR of the polyolefin resin at the time of injection is 15 to 70 g / 10 min. The fluidity of the central part of the polyolefin-based resin at this time is lowered. When EVOH is injected at the above temperature, the gas barrier resin is injected into the center of the polyolefin resin in conformity with the temperature gradient of the polyolefin resin, and the polyolefin resin and the gas barrier resin maintain a multilayer structure with a uniform thickness. While filling the bottom of the container in the cavity (150). In addition, it is preferable that the ethylene copolymerization ratio of EVOH is 30-40 mol%. This is because excellent gas barrier properties can be secured within this range.

  On the other hand, when polyamide is used as the gas barrier resin, the injection temperature in the case of polyamide is 220 to 270 ° C, more preferably 240 to 260 ° C. In the case of polyxylylenediamine dipamide, for example, the injection temperature when using the trade name “MXD6” is 250 to 290 ° C., more preferably 260 to 280 ° C. This is because the co-injected polyolefin resin and gas barrier resin can move in the cavity (150) at the same flow rate within this range.

Next, as shown in FIG. 7, the movable pin (160) is moved downward, the movable pin (160) is inscribed in the gas barrier resin supply path (120), and the supply of the gas barrier resin is stopped. In the present invention, an apparatus is used in which the polyolefin resin supply path (110) and the gas barrier resin supply path (120) are extended in this order from the injection gate (130). It is possible to inject the remaining gas barrier resin together with the polyolefin resin and then inject only the polyolefin resin. Moreover, in the vicinity of the injection gate, the gas barrier resin is subjected to pressure towards the vessel interior, the gas barrier resin is likely localized in the vessel interior. Due to this uneven distribution, the outer layer of the injection gate becomes thicker than the inner layer. In addition, since the outer layer is thicker than the inner layer, the gas barrier resin has been easily exposed in the vicinity of the injection gate, but this exposure can be avoided and the heat resistance and mechanical properties of the bottom of the container can be avoided. Strength can be increased. The time for stopping the supply of the gas barrier resin by the downward movement of the movable pin (160) can be appropriately selected according to the capacity of the cavity (150), the shape of the cavity (150), etc., but the cavity (150) After filling the container side and most of the container bottom with resin.

  In the present invention, by using the above-described apparatus, the movable pin (160) is transferred during the transition period from the co-injection of the polyolefin resin and the gas barrier resin shown in FIG. 6 to the injection of only the polyolefin resin shown in FIG. 6), the pressure of the gas barrier resin is controlled, and the gas barrier resin does not move to the polyolefin resin supply path (110) side and does not flow backward to the gas barrier resin supply path (120) side. Thus, the co-injected resin can maintain multiple layers uniformly in the cavity (150).

  Next, as shown in FIG. 8, the movable pin (160) is further moved downward to return to the position of the injection gate (130), and the supply of the polyolefin resin is also stopped. In the transition period from the injection of only the polyolefin resin shown in FIG. 7 to the supply stop of the polyolefin resin shown in FIG. 8, the movable pin (160) is kept slightly lifted from the injection gate. Holding pressure can be applied so that the system resin does not flow backward, and by applying this holding pressure, the resin injected into the cavity (150) is filled at the outermost part, and a uniform multilayer is formed and maintained. can do.

  When the movable pin (160) is inscribed in the gas barrier resin supply path (120) and the movable pin (160) is moved upward, the gas barrier resin also moves the movable pin (160). Along with this, there is a possibility that it will move upward and flow backward, and as a result, the polyolefin resin will also flow backward. Therefore, at the time of resin supply, the polyolefin resin supply path (110) and the gas barrier resin supply path (120) correspond to the movement of the movable pin (160) so as to prevent the backflow and provide a predetermined pressure. It is preferable to add and control the pressure.

The method for producing a gas barrier injection molded container of the present invention can produce a thin container having an average container bottom thickness (T) of 0.5 to 1.0 mm . For that purpose, a polyolefin resin and a gas barrier property are used. The injection amount of the resin is also small, and it is necessary to manufacture by accurately controlling the injection time in a very short time. According to the above method, two types of resins can be co-injected from one injection gate (130) only by the vertical movement of the movable pin (160) by the valve gate method, and the resin can be supplied within an extremely short time. Control becomes possible, and a gas barrier injection molded container can be manufactured in a short time. Furthermore, by using the specific device, it is possible to inject only the polyolefin resin following the co-injection of the polyolefin resin and the gas barrier resin, so that the entire bottom surface of the container has a multilayer structure of two types and three layers. can do. Also, in the vicinity of the injection gate, since the gas barrier resin receives pressure toward the inside of the container, the gas barrier resin tends to be unevenly distributed inside the container, and this uneven distribution avoids the exposure of the gas barrier resin of the injection gate. The polyolefin resin can be disposed thickly on the outer layer at the bottom of the container, and the heat resistance and mechanical strength can be enhanced.

(3) Applications The gas barrier injection-molded container produced by the present invention has a gas barrier label in-mold molded on the container side wall, and the bottom of the container is from the outer layer toward the inner layer. They are sequentially stacked. For example, by providing a gas barrier lid as shown in FIG. 2, storage of contents that require oxygen gas barrier properties because of having a gas barrier resin, for example, beverage containers, confectionery containers such as jams, jellies, Suitable for seasoning containers such as soy sauce, sauce, salad oil. Furthermore, chemicals that can be easily oxidized or must not be oxidized, such as pharmaceuticals, photographic drugs, cosmetic raw materials, IC manufacturing chemicals, beverages that require aroma, such as wine, beer, soft drinks, tea, and coffee. It can also be suitably used for small precision equipment parts that dislike contact with powder, oxygen, or the atmosphere.

In particular, in the gas barrier injection-molded container produced by the present invention, the gas barrier resin is not exposed at the bottom of the container, and therefore the gas barrier resin is not likely to be dissolved even if retort sterilization is performed. Note that the gas barrier injection-molded container produced according to the present invention may further form a printed layer, a light shielding layer, or other layers on the outer layer.

  EXAMPLES Next, although an Example is given and this invention is demonstrated concretely, these Examples do not restrict | limit this invention at all.

  Each measurement was performed by the following method.

(1) Oxygen permeability Measured by the Mocon method according to the following.

  (I) The mouth of the container manufactured in Example 1 is sealed with an acrylic plate having a thickness of 10 mm with two tubes having a diameter of 1 mm.

  (Ii) One tube attached to the acrylic plate is connected to the measuring instrument, and nitrogen gas is introduced from the other tube.

  (Iii) Nitrogen gas introduced into the container is introduced into the measuring machine through another tube, and the amount of oxygen entering through the side of the container is measured. The measurement is performed in an atmosphere at a temperature of 23 ° C. and 40% RH.

(2) Retort sterilization Aerated retort sterilization was performed at a pressure of 230 kPa and 121 ° C. for 20 minutes, and appearance of the container was observed for deformation and delamination.

Example 1
A container having a bottom diameter of 50 mm, a flange outer diameter of 70 mm, a flange inner diameter of 61 mm, a bottom wall thickness of 0.9 mm, and a side wall thickness of 0.7 mm was manufactured by co-injection molding.

PP (block copolymer type, MFR 60 g / 10 min (190 ° C.)) was used as the polyolefin resin, and EVOH (MFR, 20 g / 10 min at 210 ° C., ethylene copolymerization ratio 35 mol%) was used as the gas barrier resin. In order to detect the gas barrier resin with the naked eye, a blue pigment was added and used.

  A NETSTAL Co-Injection molding machine was used as a co-injection apparatus. As shown in FIG. 3, the apparatus includes an injection gate, a polyolefin resin supply path and a gas barrier resin supply path extending in this order from the injection gate, and a resin supply inscribed in the supply path. It is a valve gate type multilayer injection molding apparatus having a movable pin that can control the above.

  A gas barrier label in which 30 μm thick OPP, 12 μm thick inorganic vapor-deposited PET, and 30 μm thick OPP were laminated was used and attached to the inner wall of the cavity. The cavity was cooled, the polyolefin resin was heated to a temperature of 230 ° C. to solubilize, and introduced into the polyolefin resin supply path. Further, the gas barrier resin was heated to 230 ° C. to be solubilized, introduced into the gas barrier resin supply path, and injection molding was started with the movable pin fitted to the injection gate.

  The movable pin was moved upward and the polyolefin resin was injected to form the container side.

  Next, the movable pin is further moved upward to co-inject the polyolefin resin and the gas barrier resin, and then the movable pin is moved downward to stop the supply of the gas barrier resin to remove only the polyolefin resin. Injected to form the bottom of the container.

  After completion of the resin injection, the resin pressure was maintained, the cavity was cooled, and the container was taken out of the cavity after resin solidification.

The resulting container, the container bottom and the container sides, a polyolefin resin, the gas barrier resin Contact and polyolefin resin were sequentially stacked from the outer layer toward the inner layer.

There was no gas barrier resin at the container end and container side. The gas barrier resin was laminated on the entire bottom surface of the container and the lowest part on the side of the container.

  The oxygen permeability of the obtained container was measured and found to be 0.05 to 0.06 cc / pg · day · atm. The average thickness (T) of the container bottom was 900 μm. The polyolefin resin outer layer (T2) at the bottom of the container was 650 to 700 μm, and the polyolefin resin inner layer (T1) was 50 to 100 μm. The results are shown in Table 1.

(Example 2)
A co-injection container was operated in the same manner as in Example 1 except that a gas barrier label in which 30 μm thick OPP, 12 μm thick PET, 7 μm thick aluminum foil, and 30 μm thick OPP were sequentially laminated was used. Manufactured.

  The oxygen permeability of the obtained container was measured and found to be 0.003 to 0.004 cc / pg · day · atm. The average thickness (T) of the container bottom was 900 μm. The polyolefin resin outer layer (T2) at the bottom of the container was 650 to 700 μm, and the polyolefin resin inner layer (T1) was 50 to 100 μm. The results are shown in Table 1.

The gas barrier injection-molded container manufactured by the present invention forms a container side part by in-mold molding a polyolefin resin, and co-injects two kinds of polyolefin resin and gas barrier resin to form an outer layer on the container side part. , A container comprising an intermediate layer and an inner layer, and excellent in heat resistance and gas barrier properties. This container is useful because it can be manufactured in large quantities by co-injection molding.

It is container sectional drawing for demonstrating the layer structure etc. of the gas barrier injection molding container manufactured by this invention. It is sectional drawing of the container which provided the cover part in the gas barrier injection molding container manufactured by this invention. It is a schematic sectional drawing for demonstrating the mechanism of the multilayer injection molding apparatus which can be used with the manufacturing method of the gas barrier injection molding container of this invention. It is a figure explaining the injection | pouring condition of a movable pin, polyolefin resin, and gas barrier resin at the time of manufacturing a gas barrier injection molding container by this invention using the multilayer injection molding apparatus shown in FIG. It is a figure which shows the state which is fitted to an injection gate and neither resin is inject | emitted. It is a figure explaining the injection | pouring condition of a movable pin, polyolefin resin, and gas barrier resin at the time of manufacturing a gas barrier injection molding container by this invention using the multilayer injection molding apparatus shown in FIG. It is a figure which shows the state which is moved to the apparatus upper direction and is inject | pouring only polyolefin resin from the injection gate. It is a figure explaining the injection | pouring condition of a movable pin, polyolefin resin, and gas barrier resin at the time of manufacturing a gas barrier injection molding container by this invention using the multilayer injection molding apparatus shown in FIG. Furthermore, it is a figure which shows the state which moved to the apparatus upper direction and co-injected polyolefin resin and gas barrier resin from the injection gate. It is a figure explaining the injection | pouring condition of a movable pin, polyolefin resin, and gas barrier resin at the time of manufacturing a gas barrier injection molding container by this invention using the multilayer injection molding apparatus shown in FIG. It is a figure which shows the state which moved to the apparatus downward and stopped injection | pouring of gas barrier resin. It is a figure explaining the injection | pouring condition of a movable pin, polyolefin resin, and gas barrier resin at the time of manufacturing a gas barrier injection molding container by this invention using the multilayer injection molding apparatus shown in FIG. Furthermore, it is a figure which shows the state which moved below the apparatus and made it fit to the injection gate, and also stopped injection of resin. It is a figure which shows the relationship between the movable pin, the polyolefin resin annular passage, and the gas barrier resin annular passage in the AA 'line of FIG. It is a figure explaining the relationship between the movable pin in the multilayer injection molding apparatus shown in FIG. 3, a polyolefin resin supply path, and a gas barrier resin supply path.

Explanation of symbols

10 ... bottom of container,
13 ... thread bottom,
20 ... Container side,
30 ... Flange part,
40: Gas barrier resin at the bottom of the container ,
50 ... outer layer of container bottom,
50 '... inner layer of container bottom,
60 ... Container lid,
63 ... adhesive layer,
70 ... Gas barrier label,
110 ... Annular passage for supplying polyolefin resin,
113 ... Polyolefin resin supply pipe,
120... An annular passage for supplying gas barrier resin,
123 ... Gas barrier resin supply pipe,
130 ... injection gate,
150 ... cavity,
160: movable pin.

Claims (4)

A gas barrier injection molding container in which a gas barrier label and a polyolefin resin are sequentially laminated from the outer surface of the container side, and a polyolefin resin, a gas barrier resin, and a polyolefin resin are sequentially laminated from the outer surface of the container,
An injection gate, a polyolefin resin supply path extending from the injection gate, a gas barrier resin supply path extending from the polyolefin resin supply path, the polyolefin resin supply path, and a gas barrier resin supply Using a valve gate type multi-layer injection molding device having a movable pin inscribed in the road and controlling the resin supply,
After mounting the gas barrier label in the cavity, the movable pin is detached from the polyolefin resin supply path to inject the polyolefin resin to form the container side part,
The movable pin is separated from the polyolefin resin supply path and the gas barrier resin supply path to co-inject the polyolefin resin and the gas barrier resin, and then the movable pin is inserted into the gas barrier resin supply path. A method for producing a gas barrier injection-molded container, wherein the bottom of the container is formed by injecting only the polyolefin resin in contact therewith. The polyolefin resin is characterized injected at a temperature in the 150 to 300 ° C., the manufacturing method of the gas barrier injection molding vessel of claim 1, wherein. The method for manufacturing a gas barrier injection molding container according to claim 1 or 2 , wherein the gas barrier resin is EVOH and is injected at a temperature of 190 to 240 ° C. 4. The gas barrier injection-molded container according to claim 3 , wherein the EVOH is EVOH having an MFR of 10 to 30 g / 10 min at a temperature of 210 ° C. and an ethylene copolymerization ratio of 30 to 40 mol%. Method.