JP2018015992A - Method for producing composite container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a composite container, without causing defects such as bubbles on a surface of a plastic member, capable of satisfactorily expanding a preform and the plastic member.SOLUTION: A method for producing a composite container comprising: a step of preparing a preform made of a plastic material; a step of preparing a plastic member; a step of heating the perform; a step of inserting the preform into the plastic member; a step of inserting the preform and the plastic member into a blow molding die while heating the preform and the plastic member; and a step of integrally expanding the preform and the plastic member by subjecting the preform and the plastic member after heating to blow molding.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a composite container.

  Recently, plastic bottles for storing content liquids such as foods and drinks have become common, and such plastic bottles store content liquids.

  A plastic bottle containing such a content liquid is manufactured by inserting a preform into a mold and biaxially stretch-blow molding.

  By the way, in the conventional biaxial stretch blow molding method, for example, a preform including a single layer material such as PET or PP, a multilayer material, a blend material, or the like is used to form a container shape. However, in the conventional biaxial stretch blow molding method, the preform is generally simply formed into a container shape. For this reason, when various functions and characteristics (barrier property, heat retaining property, etc.) are given to the container, the means is limited, for example, by changing the material constituting the preform. In particular, it is difficult to have different functions and characteristics depending on the part of the container (for example, the trunk and the bottom).

  In the previous application (Japanese Patent Application Laid-Open No. 2015-128858), the present applicant has proposed a composite container capable of imparting various functions and characteristics to the container.

JP2015-128858A

The composite container disclosed in Patent Document 1 is obtained by heating and blow-molding a composite preform including a preform and a plastic member mounted so as to surround the outside of the preform.
Recently, the present inventors have disclosed a temperature at which a preform covered with a plastic member can be well blow-molded in a heating step of the composite preform for favorably expanding the composite preform by blow molding. As a result, it has been found that there is a possibility that the plastic member is excessively heated to cause defects such as bubbles on the surface.

  The present invention has been made on the basis of the above knowledge, and its purpose is to cause the preform and the plastic member to expand well by blow molding without causing defects such as bubbles on the surface of the plastic member. It is providing the manufacturing method of the composite container which can be performed.

The method for producing the composite container of the present invention comprises:
Preparing a preform made of plastic material;
Preparing a plastic member;
Heating the preform;
A process of fitting the preform into a plastic member;
Heating the preform and plastic member and inserting it into a blow mold; and
A step of inflating the preform and the plastic member integrally by performing blow molding on the preform and the plastic member after heating;
It is characterized by comprising.

  In the above aspect, after the step of fitting the preform into the plastic member, the preform and the plastic member are heated and before the step of inserting into the blow molding die, the plastic member is heated and brought into close contact with the preform. A process may be included.

  In the said aspect, it is preferable that the heating temperature of the said preform in the heating process of a preform is 70 degreeC or more and 120 degrees C or less.

  In the said aspect, it is preferable that the temperature of the preform in the process of heating the preform and the plastic member and inserting it into the blow molding die is 80 ° C. or more and 135 ° C. or less.

  In the said aspect, it is preferable that the heating temperature of the plastic member in the process of heating a preform and a plastic member and inserting in a blow molding die is 80 degreeC or more and 180 degrees C or less.

  According to the present invention, there is provided a composite container that does not cause defects such as bubbles on the surface of a plastic member, and that can well expand a preform and a plastic member by blow molding, and has a good appearance. Can be obtained.

FIG. 1 is a partial vertical sectional view of a composite container 10A manufactured by a method according to the present invention. 2 is a horizontal sectional view taken along the line II-II of the composite container shown in FIG. FIG. 3 is a partial vertical sectional view showing the preform 10a and the plastic member 40a after fitting. FIG. 4 is a perspective view showing the plastic member 40a. FIG. 5 is a vertical sectional view showing a state in which the preform 10a is fitted into the heat-shrinkable plastic member 40a. FIG. 6 is a front view of the heat-shrinkable plastic member 40a. FIG. 7 is a front view of the preform 10a. FIG. 8 is a schematic view showing an embodiment of a method for producing the plastic member 40a. FIG. 9 is a schematic view showing an embodiment of a method for producing the plastic member 40a. FIG. 10 is a diagram illustrating the shape of the margin part subjected to thermocompression bonding. FIG. 11 is a schematic view showing a method for manufacturing the composite container 10A.

Manufacturing method of composite container 10A The manufacturing method of the composite container 10A according to the present invention includes:
Preparing a preform 10a made of plastic material;
Preparing a tubular plastic member 40a;
Heating the preform 10a;
A step of fitting the preform 10a into the plastic member 40a;
Heating the preform 10a and the plastic member 40a and inserting the preform 10a and the plastic member 40a into a blow mold;
A step of blow-molding the preform 10a and the plastic member 40a after heating to expand the preform 10a and the plastic member 40a integrally.
In addition, the method of the present invention may be used after the step of fitting the preform 10a into the plastic member 40a, if desired, before the step of heating and inserting the preform 10a and the plastic member 40a into the blow mold. It includes a step of heating the manufacturing member 40a and bringing it into close contact with the preform 10a.

Composite container 10A
As shown in FIG. 1, a composite container 10A obtained by the method of the present invention includes a container body 10 made of a plastic material located inside and a plastic member 40 provided in close contact with the outside of the container body 10. I have.

Container body 10
Among these, the container body 10 includes a mouth portion 11, a neck portion 13 provided below the mouth portion 11, a shoulder portion 12 provided below the neck portion 13, a trunk portion 20 provided below the shoulder portion 12, and The bottom part 30 provided below the trunk | drum 20 is provided. In the present specification, “upper” and “lower” refer to the upper side and the lower side in a state where the composite container 10A is erected (FIG. 1), respectively.

  The mouth portion 11 has a screw portion 14 screwed to a cap (not shown) and a flange portion 17 provided below the screw portion 14. The shape of the mouth portion 11 may be a conventionally known shape, or may be a multi-threaded screw or a stopper shape.

  The neck portion 13 is located between the flange portion 17 and the shoulder portion 12 and has a substantially cylindrical shape having a substantially uniform diameter. The shoulder 12 is located between the neck 13 and the trunk 20 and has a shape whose diameter gradually increases from the neck 13 toward the trunk 20.

  Furthermore, the trunk | drum 20 has a cylindrical shape with a substantially uniform diameter as a whole. However, the present invention is not limited to this, and the body portion 20 may have a polygonal cylindrical shape such as a rectangular cylindrical shape or an octagonal cylindrical shape. Or the trunk | drum 20 may have a cylinder shape with a horizontal cross section which is not uniform toward upper direction from the downward direction. Moreover, in this Embodiment, although the unevenness | corrugation is not formed in the trunk | drum 20, and has a substantially flat surface, it is not restricted to this. For example, unevenness such as a panel or a groove may be formed on the body portion 20.

  The bottom portion 30 has a concave portion 31 located in the center and a grounding portion 32 provided around the concave portion 31. The shape of the bottom 30 is not particularly limited, and may have a conventionally known bottom shape (for example, a petaloid bottom shape or a round bottom shape).

  Moreover, although the thickness of the container main body 10 in the trunk | drum 20 is not limited to this, For example, it can be made thin to about 50 micrometers-250 micrometers. Furthermore, the weight of the container body 10 is not limited to this, but for example, when the container body 10 has an internal volume of 500 mL, it can be 10 g to 20 g. Thus, by reducing the thickness of the container main body 10, the weight of the container main body 10 can be reduced.

  In one embodiment, the container body 10 can be produced by biaxially stretch blow molding a preform 10a described later.

  In order to enhance the barrier property of the container, a vapor deposition film such as a diamond-like carbon film or a silicon oxide thin film may be formed on the inner surface of the container body 10.

  The container main body 10 may consist of a bottle with a full capacity of 100 mL to 2000 mL, for example. Alternatively, the container main body 10 may be a large bottle having a full capacity of, for example, 10L to 60L.

Plastic member 40
The plastic member 40 is in close contact with the outer surface of the container body 10 in a thinly extended state, and is attached to the container body 10 without being easily moved or rotated. As shown in FIG. 1, the plastic member 40 is provided over the entire circumferential direction so as to surround the container body 10, and has a substantially circular horizontal cross section.

  The plastic member 40 is provided by surrounding the outer side of the preform 10a as will be described later, closely contacting the outer side of the preform 10a, and then biaxially stretched and blow-molded together with the preform 10a. Can be obtained.

  As shown in FIG. 1, the plastic member 40 can be provided so as to cover the shoulder portion 12, the trunk portion 20, and the bottom portion 30 of the container body 10 except for the mouth portion 11 and the neck portion 13. With such a configuration, desired functions and characteristics can be imparted to the shoulder portion 12, the trunk portion 20, and the bottom portion 30 of the container body 10.

  The plastic member 40 may be provided in the entire region or a partial region other than the mouth portion 11 of the container body 10. For example, the plastic member 40 may be provided so as to cover the neck portion 13, the shoulder portion 12, the trunk portion 20, and the bottom portion 30 of the container body 10 except for the mouth portion 11. Further, the number of plastic members 40 is not limited to one, and a plurality of plastic members 40 may be provided. For example, you may provide the two plastic members 40 in the outer surface of the shoulder part 12, and the outer surface of the bottom part 30, respectively.

  Moreover, the thickness of the plastic member 40 is not limited to this, but can be set to, for example, about 5 μm to 50 μm in a state of being attached to the container body 10.

Further, since the plastic member 40 is not welded or bonded to the container body 10, it can be separated (separated) from the container body 10 and removed.
As a method of separating (peeling) the plastic member 40 from the container body 10, for example, the plastic member 40 is cut using a blade or the like, or a cutting line is provided in advance in the plastic member 40, and the cutting line is followed. Thus, the plastic member 40 can be peeled off. Since the plastic member 40 can be separated and removed from the container body 10 by the method as described above, the colorless and transparent container body 10 can be recycled as in the conventional case.

Process for Preparing Preform 10a As shown in FIG. 3, the preform 10a includes a mouth portion 11a, a body portion 20a connected to the mouth portion 11a, and a bottom portion 30a connected to the body portion 20a. . Of these, the mouth portion 11 a corresponds to the mouth portion 11 of the container body 10 described above, and has substantially the same shape as the mouth portion 11. Moreover, the trunk | drum 20a respond | corresponds to the neck part 13, the shoulder part 12, and the trunk | drum 20 of the container main body 10 mentioned above, and has a substantially cylindrical shape. The bottom 30a corresponds to the bottom 30 of the container body 10 described above, and has a substantially hemispherical shape.

In one embodiment, the preform 10a can be manufactured by injection-molding a resin material using a conventionally known apparatus.
As the resin material, it is preferable to use a thermoplastic resin, particularly PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PC (polycarbonate), or ionomer resin. Moreover, you may blend and use the various resin mentioned above.
In addition, the preform 10a may contain colorants such as red, blue, yellow, green, brown, black, and white. However, in consideration of ease of recycling, the preform 10a does not contain these colorants and is colorless. It is preferably transparent.

Moreover, the container main body 10 can be made into the multilayer molding bottle of 2 layers or more by producing the multilayer preform 10a of 2 layers or more by injection molding.
For example, the intermediate layer includes a resin (intermediate layer) having gas barrier properties and light shielding properties such as MXD6, MXD6 + fatty acid salt, PGA (polyglycolic acid), EVOH (ethylene vinyl alcohol copolymer) or PEN (polyethylene naphthalate) A multilayer molded bottle having gas barrier properties, light-shielding properties, and the like can be obtained by forming a preform 10a consisting of three or more layers as a layer and then blow-molding. As the intermediate layer, a resin blended with the various resins described above may be used.
Moreover, you may use what is marketed other than the preform 10a produced as mentioned above.

  Further, by mixing an inert gas (nitrogen gas, argon gas) with the thermoplastic resin melt, a foam preform having a foam cell diameter of 0.5 to 100 μm is formed, and this foam preform is blow-molded. Thus, the container body 10 may be manufactured. Since such a container main body 10 contains the foam cell, the light shielding property of the container main body 10 whole can be improved.

Step of Preparing the Plastic Member 40a In one embodiment, as shown in FIG. 4A, the plastic member 40a is formed in a tube shape (bottomed cylindrical shape), and includes a cylindrical body portion 41 and a body portion. And a bottom 42 connected to 41. In this case, since the bottom portion 42 of the plastic member 40a covers the bottom portion 30a of the preform 10a, various functions and characteristics are imparted to the bottom portion 30 in addition to the trunk portion 20 when the composite container 10A is formed. be able to.
Moreover, in other embodiment, as shown in FIG.4 (b), the plastic member 40a consists of a tube shape (bottomless cylindrical shape) as a whole, and may have the cylindrical trunk | drum 41. FIG. .
In still another embodiment, as shown in FIGS. 4 (c) and 4 (d), the plastic member 40a is formed by forming a film into a cylindrical shape and bonding its end portions together. There may be. In this case, as shown in FIG. 4 (c), the plastic member 40a may be configured in a tube shape (bottomless cylindrical shape) having a body portion 41, and as shown in FIG. 4 (d), The bottom part 42 may be bonded to form a bottomed cylindrical shape.
The plastic member 40a may or may not have heat shrinkability, but it should have heat shrinkability from the viewpoint of adhesion to the preform 10a. Is preferred.

Moreover, the length of the plastic member 40a is longer than that of the preform 10a, and it is preferable to have a blank portion 80a at one end thereof as shown in FIG. The length of the blank portion 80a is preferably 3 mm or more, and more preferably 5 mm or more and 20 mm or less. Since the plastic member 40a has the blank portion 80a, the bottom portion 30a can be formed by a thermocompression bonding process described later even if the plastic member 40a has a tubular shape.
The length of the heat-shrinkable plastic member 40a refers to the length X including the blank portion 80a, as shown in FIG. Moreover, the length of the preform 10a means the length Y from the neck part 13a to the bottom part 30a, as FIG. 7 shows.

The plastic member 40a is, for example, PE, PP, PET, PEN, poly-4-methylpentene-1, polystyrene, AS resin, ABS tree, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl alcohol, polyvinyl. Acetal, polyvinyl butyral, diallyl phthalate resin, fluororesin, polymethyl methacrylate, polyacrylic acid, polymethyl acrylate, polyacrylonitrile, polyacrylamide, polybutadiene, polybutene-1, polyisoprene, polychloroprene, ethylene propylene rubber, Butyl rubber, nitrile rubber, acrylic rubber, silicone rubber, fluoro rubber, nylon 6, nylon 6,6, MXD6, aromatic polyamide, polycarbonate, poly (terephthalate), poly (terephthalate) , Ethylene naphthalate, U polymer, liquid crystal polymer, modified polyphenylene ether, polyether ketone, polyether ether ketone, unsaturated polyester, alkyd resin, polyimide, polysulfone, polyphenylene sulfide, polyethersulfone, silicone resin, polyurethane, phenol It can be produced using a resin material containing resin, urea resin, polyethylene oxide, polypropylene oxide, polyacetal, epoxy resin, ionomer resin, and the like.
Among these, it is preferable to include thermoplastic inelastic resins such as PE, PP, PET, and PEN.
The resin material may include a copolymer obtained by polymerizing two or more monomer units constituting the above-described resin. Furthermore, the resin material may comprise two or more of the above-described resins.

The plastic member 40a may be a single layer or a multilayer.
In the case where the plastic member 40a is composed of multiple layers, for example, the layer configuration of the innermost surface and the outermost surface may be the same or different.
Specific examples of the layer structure include, from the innermost surface, low density PE / adhesive layer / EVOH / adhesive layer / low density PE, PP / adhesive layer / EVOH / adhesive layer / PP, and the like.
Examples of the adhesive constituting the adhesive layer in this case include a polyvinyl acetate adhesive, a polyacrylate adhesive, a cyanoacrylate adhesive, an ethylene copolymer adhesive, a cellulose adhesive, and a polyester adhesive. Examples thereof include an adhesive, a polyamide-based adhesive, a polyimide-based adhesive, an amino resin-based adhesive, a phenol resin-based adhesive, an epoxy-based adhesive, a polyurethane-based adhesive, a rubber-based adhesive, and a silicone-based adhesive.

The plastic member 40a may include a material having a gas barrier property such as an oxygen barrier property or a water vapor barrier property.
In this case, without using a multi-layer preform or a preform containing a blend material as the preform 10a, the gas barrier property of the composite container 10A is improved, oxygen is prevented from entering the container, and the content liquid is prevented from deteriorating. In addition, it is possible to prevent the evaporation of water vapor from the inside of the container to the outside and to prevent the internal volume from decreasing.
For example, the plastic body 40 may be provided in the entire region of the shoulder portion 12, the neck portion 13, the body portion 20, and a part of the bottom portion 30 in the container body 10, and the gas barrier property of this portion may be enhanced.
As such a material, PE, PP, MXD-6, PGA, EVOH, PEN, or an oxygen absorbing material such as a fatty acid salt may be mixed with these materials.
In addition, when the plastic member 40a consists of a multilayer, you may provide the layer which consists of material which has gas barrier property.

The plastic member 40a may include a material having light barrier properties such as ultraviolet rays.
In this case, the light barrier property of the composite container 10A can be improved and the content liquid can be prevented from being deteriorated by ultraviolet rays or the like without using a multilayer preform or a preform containing a blend material as the preform 10a.
For example, a plastic member 40a may be provided in the entire region of the shoulder portion 12, the neck portion 13, and the body portion 20 and a part of the bottom portion of the container body 10 to enhance the ultraviolet barrier property of this portion.
As such a material, a resin material containing two or more kinds of the above-described resins, or a material obtained by adding a light-shielding resin to PET, PE, or PP can be considered. Moreover, you may use the foaming member with the foam cell diameter of 0.5-100 micrometers produced by mixing inert gas (nitrogen gas, argon gas) with the melt of a thermoplastic resin.
In addition, when the plastic member 40a consists of a multilayer, you may provide the layer which consists of a material which has light-barrier property.

In addition, the plastic member 40a may include a material (a material having a low thermal conductivity) having a higher heat retaining property or a lower heat retaining property than a plastic material constituting the preform 10a.
In this case, it is possible to make it difficult for the temperature of the content liquid to be transmitted to the surface of the composite container 10A without increasing the thickness of the container body 10 itself. Thereby, the heat retaining property or cold retaining property of the composite container 10A is enhanced.
For example, the plastic member 40 may be provided on the whole or a part of the body 20 in the container body 10 to enhance the heat retaining property or the cold retaining property of the body 20. Further, when the user grips the composite container 10A, it is prevented that the composite container 10A becomes difficult to hold due to being too hot or too cold. Examples of such materials include foamed polyurethane, polystyrene, PE, PP, phenol resin, polyvinyl chloride, urea resin, silicone, polyimide, melamine resin, and the like.
In addition, when the plastic member 40a consists of a multilayer, you may provide the layer which consists of a material with high heat retention or cold retention (material with low heat conductivity).
Moreover, it is preferable to mix a hollow particle with the resin material containing these resins. The average particle diameter of the hollow particles is preferably 1 to 200 μm, and more preferably 5 to 80 μm. The hollow particles may be organic hollow particles composed of a resin or the like, or may be inorganic hollow particles composed of glass or the like. Hollow particles are preferred. Examples of the resin constituting the organic hollow particles include styrene resins such as cross-linked styrene-acrylic resins, (meth) acrylic resins such as acrylonitrile-acrylic resins, phenolic resins, fluorine resins, polyamide resins, and polyimides. Resin, polycarbonate resin, polyether resin and the like. Also, Ropeke HP-1055, Ropeke HP-91, Ropeke OP-84J, Ropeke Ultra, Ropeke SE, Ropeke ST (manufactured by Rohm and Haas), Nipol MH-5055 (manufactured by Nippon Zeon), SX8782 Commercially available hollow particles such as SX866 (manufactured by JSR Corporation) can also be used.
As content of a hollow particle, when the plastic member 40a consists of a single layer, it is preferable that it is 0.01-50 mass parts with respect to 100 mass parts of resin materials contained in the plastic member 40a. More preferably, it is -20 mass parts. Moreover, when the plastic member 40a consists of a multilayer, it is preferable that it is 0.01-50 mass parts with respect to 100 mass parts of resin materials contained in the layer of the plastic member 40a in which a hollow particle is contained. More preferably, it is -20 mass parts.

Further, the plastic member 40a may include a material that is less slippery than the plastic material constituting the preform 10a.
In this case, the user can easily hold the composite container 10 </ b> A without changing the material of the container body 10. For example, a plastic member 40 may be provided on all or part of the body 20 of the container body 10 so that the body 20 can be easily held.
In addition, when the plastic member 40a consists of a multilayer, you may provide the layer which consists of material which is harder to slip than the plastic material which comprises the preform 10a. In this case, the layer is preferably the outermost layer of the plastic member 40a.

Further, the plastic member 40a may be designed or printed. In this case, it is possible to display images and characters on the composite container 10A without separately providing a label or the like to the container body 10 after blow molding.
For example, the plastic member 40 may be provided on all or part of the trunk 20 in the container body 10, and images or characters may be displayed on the trunk 20.
Printing can be performed by a printing method such as an inkjet method, a gravure printing method, an offset printing method, or a flexographic printing method. For example, when the ink jet method is used, a printing layer can be formed by applying UV curable ink to the plastic member 40a (40), irradiating it with UV, and curing it. This printing may be performed on the plastic member 40a before being fitted into the preform 10a, or may be performed in a state where the plastic member 40a is provided outside the preform 10a. Furthermore, the plastic member 40 of the composite container 10A after blow molding may be printed.

  Next, a method for manufacturing the plastic member 40a will be described. In addition, you may use what is marketed instead of the plastic member 40a produced as follows.

In one embodiment, the plastic member 40a can be manufactured by molding a resin sheet containing the resin material described above.
Examples of the molding method include deep-drawing molding, or a method of molding a resin sheet into a tube shape and fusing or bonding the end portions thereof.
Moreover, the plastic member 40a composed of multiple layers can be obtained by molding a laminated resin sheet obtained by laminating two or more resin sheets via the above-described adhesive.
A commercial item may be used for the said resin sheet, and it can manufacture it by a conventionally well-known method. In this invention, it is preferable to manufacture by extrusion molding, and it is preferable that extrusion molding is performed by the T-die method or the inflation method.

In one embodiment, the plastic member 40a is as shown in FIG.
(1) First, the resin material 51 is heated and melted and extruded from the die 52 into a tube shape to form a tube-shaped parison 53.
(2) Next, as shown in FIG. 8B, for example, the tubular parison 53 is sandwiched by a two-part mold 54,
(3) Next, as shown in FIG. 8 (c), air is blown into the tubular parison 53 from the blow nozzle 55, the tubular parison 53 is molded according to the mold 54, cooled, opened, and taken out. By sequentially performing, a bottomed cylindrical plastic member 40a as shown in FIG. 8D can be obtained (direct blow molding).
According to this method, the design of the plastic member 40a obtained can be changed by changing the design of the mold, and the plastic member 40a having high adhesion to the preform 10a can be produced. .

In one embodiment, the heat-shrinkable plastic member 40a can be produced by the following method.
First, the above-described resin material or the like is heated and melted in an extrusion apparatus, and the molten resin material or the like is continuously extruded from a ring die and cooled to be formed into an unstretched extruded tube 1 (FIG. 9A )reference). The multilayer plastic member 40a can be manufactured by co-extruding two or more resin materials.
Next, one end of the extruded tube is closed by welding or bonding one end of the unstretched extruded tube.
Further, the extruded tube 1 whose one end is closed is disposed in a mold 2 having an inner diameter larger than the outer diameter of the extruded tube 1 (see FIG. 9B).
Next, the blow device 3 is disposed (mounted) on the other end of the extruded tube 1 (see FIG. 9C). At this time, it is preferable that the blower 3 is in close contact with the extruded tube 1 so that air does not leak between them.
Subsequently, the extruded tube 1, the mold 2 and the blow device 3 are sent to the heating furnace 4 in this arrangement, and heated to 70 to 150 ° C. inside the heating furnace 4 (see FIG. 9D). As the heating furnace 4, a hot-air circulating heating furnace may be used in order to make the inside uniform. Or you may heat these by passing the extrusion tube 1, the metal mold | die 2, and the blow apparatus 3 in the heated liquid.
Next, the extruded tube 1, the mold 2 and the blow device 3 are taken out from the heating furnace 4, and air is blown into the extruded tube 1 from the blow device 3, whereby the inner surface of the extruded tube 1 is stretched under pressure. Thereby, the extruded tube 1 expands and expands along the inner surface shape of the mold 2 (see FIG. 9E).
Thereafter, the extruded tube 1 is cooled in cold water while air is blown out from the blower 3, and the extruded tube is taken out from the mold 2 (see FIG. 9 (f)). By cutting this into a desired size, a heat-shrinkable plastic member 40a can be obtained (see FIG. 9 (g)).

  In one embodiment, the plastic member 40a can also be obtained by an injection molding method. Specifically, first, a mixture containing the above resin material and the like is heated and melted. Next, the heated and melted mixture is injected into a mold. The plastic member 40a can also be obtained by cooling it and taking it out of the mold.

Step of heating preform 10a The method of the present invention includes a step of heating preform 10a. By heating the preform 10a before fitting into the plastic member 40a, the heating time after fitting can be shortened, and excessive heating of the plastic member 40a can be prevented. Further, since the preform 10a can be directly heated, the working efficiency can be improved.

The heating temperature of the preform 10a is preferably 70 ° C. or higher and 120 ° C. or lower, and more preferably 80 ° C. or higher and 110 ° C. or lower.
The heating method is not particularly limited, and can be appropriately performed using infrared rays, warm air, or the like.
The heating temperature is the surface temperature of the preform 10a at the time of heating, not the irradiation temperature of infrared rays or warm air.
Further, the heating time of the preform 10a is preferably 5 seconds or more and 300 seconds or less, more preferably 8 seconds or more and 90 seconds or less, although it depends on the heating device and the temperature used. By setting the heating time of the preform 10a within the above numerical range, the subsequent blow molding can be performed more favorably.

Step of fitting the preform 10a into the plastic member 40a The method of the present invention includes the step of fitting the preform 10a into the plastic member 40a.

The process of heating the plastic member 40a and bringing it into close contact with the preform 10a In the method of the present invention, when the plastic member 40a has heat shrinkability, the plastic member 40a is heated and brought into close contact with the preform 10a after fitting. A process may be included.
The heating temperature of the plastic member 40a is preferably 50 ° C. or higher and 150 ° C. or lower, and more preferably 70 ° C. or higher and 120 ° C. or lower.
The heating method is not particularly limited, and can be appropriately performed using infrared rays, warm air, or the like.
The heating temperature is the surface temperature of the plastic member 40a at the time of heating, not the irradiation temperature of infrared rays or warm air.
Further, the heating time of the plastic member 40a is preferably 2 seconds or longer and 30 seconds or shorter, more preferably 5 seconds or longer and 15 seconds or shorter, although it depends on the heating device used and the operating temperature. By setting the heating time of the preform 10a within the above numerical range, the subsequent blow molding can be performed more favorably.

The process of thermocompression bonding the blank portion 80a of the plastic member 40a The method of the present invention includes a fitting step or a plastic member 40a when the plastic member 40a has a tubular shape as shown in FIG. A step of thermocompression bonding the blank portion 80a of the plastic member 40a may be included after the step of heating and closely contacting the preform 10a.
The method of thermocompression bonding is not particularly limited, and is not particularly limited as long as it can be crimped by sandwiching a blank portion heated by infrared rays or warm air, for example, metal or heat resistant These resin-made instruments (hereinafter, sometimes referred to as “crimping instruments”) may be used, or they may be combined.

  Further, the shape of the blank portion 80a after the thermocompression bonding is not particularly limited, and may be an arbitrary shape as shown in FIG.

  The surface of the crimping device may be flat or partially or entirely uneven.

  The crimping instrument may have a heating mechanism on its surface. Thereby, the crimping | compression-bonding intensity | strength of the blank part 80a can be raised more. The heating temperature of the surface of the crimping device is preferably, for example, 100 ° C. or more and 250 ° C. or less. Further, from the viewpoint of maintaining a good appearance on the surface of the plastic member 40a, the pressure bonding time is preferably 5 seconds or less.

The pressure during pressure bonding is preferably 50 N / cm ² or more and 1000 N / cm ² or less, more preferably 100 N / cm ² or more and 500 N / cm ² or less.

  The temperature of the heat-shrinkable plastic member 40a at the time of pressure bonding is preferably 80 ° C. or higher and 200 ° C. or lower, although it depends on the material.

  Further, the blank portion 80a after thermocompression bonding may be cut to an appropriate length as desired. By cutting the blank portion into an appropriate length (for example, about 2 mm), the appearance of the bottom portion when the composite container is formed becomes good.

Heating and Blow Molding Step of Preform 10a and Plastic Member 40a The preform 10a and the plastic member 40a are heated by a heating device 51 as shown in FIG.
In one embodiment, the preform 10a and the plastic member 40a are evenly heated in the circumferential direction by the heating device 51 while rotating with the mouth portion 11a facing downward.

The heating temperature of the preform 10a is preferably 80 ° C. or higher and 135 ° C. or lower, and more preferably 85 ° C. or higher and 110 ° C. or lower.
The heating temperature of the plastic member 40a is preferably 80 ° C. or higher and 180 ° C. or lower, and more preferably 90 ° C. or higher and 130 ° C. or lower.
The heating method is not particularly limited, and can be appropriately performed using infrared rays, warm air, or the like.
The heating temperature is the surface temperature of the preform 10a and the plastic member 40a at the time of heating, and is not an irradiation temperature such as infrared rays or warm air.
Further, the heating time of the preform 10a and the plastic member 40a is preferably 0.5 seconds or more and 60 seconds or less, although it depends on the heating device to be used and the use temperature, and is 2 seconds or more and 20 seconds or less. More preferably. By setting the heating time to the above numerical range, it is possible to prevent the plastic member 40a from being heated excessively and causing defects such as bubbles on the surface thereof.
The heating of the preform 10a and the plastic member 40a is preferably performed before the temperature of the preform 10a heated by the process of heating the preform 10a alone is lowered. The temperature of the preform 10a immediately before heating the member 40a is preferably 65 ° C. or higher, and more preferably 75 ° C. or higher. Moreover, it is preferable that the heating by this process is performed within 60 seconds after the process of heating the preform 10a alone, and it is more preferable that the heating is performed within 40 seconds.

After heating, the preform 10a and the plastic member 40a are sent to the blow molding die 50 (see FIG. 11B). A conventionally well-known thing can be used for a blow molding die.
In one embodiment, the blow mold 50 includes a pair of body molds 50a and 50b and a bottom mold 50c that are divided from each other (see FIG. 11B). In FIG. 11B, the pair of body molds 50a and 50b are open to each other, and the bottom mold 50c is raised upward. In this state, the preform 10a and the plastic member 40a are inserted between the pair of body molds 50a and 50b. As shown in FIG. 11 (c), after the bottom mold 50c is lowered, the pair of body molds 50a and 50b are closed and sealed by the pair of body molds 50a and 50b and the bottom mold 50c. A blow molding die 50 is configured.

In the blow molding die 50, air is press-fitted into the preform 10a, and biaxial stretch blow molding is performed on the preform 10a and the plastic member 40a, thereby obtaining the composite container 10A.
During blow molding, the body molds 50a and 50b are preferably heated to 30 ° C. or higher and 80 ° C. or lower, and the bottom mold 50c is preferably cooled to 5 ° C. or higher and 25 ° C. or lower.
In the blow molding die 50, the preform 10a and the plastic member 40a are integrally blow-molded, so that they are shaped into a shape corresponding to the inner surface of the blow molding die 50.
Next, as shown in FIG. 11 (d), the pair of body molds 50 a and 50 b and the bottom mold 50 c are separated from each other, and the composite container 10 </ b> A is taken out from the blow mold 50.

<Example 1>
(Step of preparing the preform 10a)
A PET preform 10a shown in FIG. 7 was produced using an injection molding machine. The weight of this preform 10a was 23.8 g.

(Process of preparing plastic member 40a)
The polyolefin resin was melted and extruded from a ring die. Next, the extruded tube inner surface was pressurized, or the tube outer surface was subjected to negative pressure from the inner surface to expand the diameter, thereby producing a heat-shrinkable plastic member 40a having an inner diameter of 27 mm as shown in FIG.

(Step of heating the preform 10a)
The prepared preform 10a was heated using an infrared heater until the surface of the preform 10a reached 90 ° C. The heating time was 25 seconds.

(Fitting process)
The preform 10a was fitted into the plastic member 40a by manual work.

(Step of heating the plastic member 40a and bringing it into close contact with the preform 10a)
After the fitting, the plastic member 40a was heated using a warm air dryer until the surface of the plastic member 40a reached 110 ° C., and the plastic member 40a was thermally contracted and adhered to the preform 10a. The heating time was 8 seconds.

(Manufacture of composite containers)
Next, the preform 10a and the plastic member 40a were heated using an infrared heater until the preform 10a reached 100 ° C. and conveyed to a blow molding die shown in FIG. The surface of the plastic member 40a at that time was 120 ° C. In this blow molding die, the preform 10a and the plastic member 40a after being fitted were blow-molded to obtain a composite container 10A having a full injection capacity of 500 mL. On the surface of the composite container 10A, no defects such as bubbles were found, and the appearance was good. The heating time was 5 seconds. Moreover, the time required from the process of heating the preform 10a to this process was 30 seconds.

<Comparative Example 1>
A PET preform 10a shown in FIG. 7 was produced using an injection molding machine. The weight of this preform 10a was 23.8 g.
The polyolefin resin was melted and extruded from a ring die. Next, the extruded tube inner surface was pressurized, or the tube outer surface was subjected to negative pressure from the inner surface to expand the diameter, thereby producing a heat-shrinkable plastic member 40a having an inner diameter of 27 mm as shown in FIG.
Unlike Example 1, the preform 10a was fitted by hand without heating the preform 10a.
After the fitting, the plastic member 40a was heated using a warm air dryer until the surface of the plastic member 40a reached 110 ° C., and the plastic member 40a was thermally contracted and adhered to the preform 10a. The heating time was 8 seconds.
Next, the preform 10a and the plastic member 40a were heated using an infrared heater until the preform 10a reached 100 ° C. and conveyed to a blow molding die shown in FIG. The surface of the plastic member at that time was 140 ° C. In this blow molding die, the preform 10a and the plastic member 40a after being fitted were blow-molded to obtain a composite container 10A having a full injection capacity of 500 mL. Bubbles were generated on the surface of the composite container 10A, and the appearance was not good. The heating time for the preform 10a and the plastic member 40a was 25 seconds.

Claims (5)

Preparing a preform made of plastic material;
Preparing a plastic member;
Heating the preform;
Fitting the preform into the plastic member;
Heating the preform and the plastic member and inserting it into a blow mold; and
Expanding the preform and the plastic member integrally by performing blow molding on the preform and the plastic member after heating;
A process for producing a composite container, comprising:   After the step of fitting the preform into the plastic member, before the step of heating the preform and the plastic member and inserting into the blow mold, the plastic member is heated and brought into close contact with the preform The method of claim 1, further comprising a step.   The method according to claim 1 or 2, wherein a heating temperature of the preform in the heating step of the preform is 70 ° C or higher and 120 ° C or lower.   The temperature of the preform in the step of heating the preform and the plastic member and inserting it into a blow molding die is 80 ° C or higher and 135 ° C or lower. The method described.   The heating temperature of the plastic member in the step of heating the preform and the plastic member and inserting the preform and the plastic member into a blow molding die is 80 ° C or higher and 180 ° C or lower. The method according to item.