JP6759810B2 - Manufacturing method of composite container - Google Patents

Description

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

Recently, plastic bottles have become common as bottles for containing the contents of foods and drinks, and such plastic bottles contain the contents.

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

By the way, in the conventional biaxial stretching blow molding method, a container shape is formed by using a preform containing, for example, a single layer material such as PET or PP, a multilayer material or a blend material. However, in the conventional biaxial stretching blow molding method, it is general that the preform is simply molded into a container shape. Therefore, when the container is to have various functions and properties (barrier property, heat retention property, etc.), the means thereof is limited, for example, changing the material constituting the preform. In particular, it is difficult to give different functions and characteristics depending on the part of the container (for example, the body and the bottom).

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

Japanese Unexamined Patent Publication No. 2015-128858

The composite container disclosed in Patent Document 1 is obtained by heating and blow molding a preform and a composite preform including a plastic member mounted so as to surround the outside of the preform.
Now, in the heating process of the composite preform for satisfactorily expanding the composite preform by blow molding, the present inventors can perform good blow molding of the preform covered with a plastic member. It has been found that the plastic member may be excessively heated by heating to the extent that defects such as air bubbles may be generated on the surface of the plastic member.

The present invention has been made based on the above findings, and an object of the present invention is to satisfactorily expand the preform and the plastic member by blow molding without causing defects such as air bubbles on the surface of the plastic member. It is to provide a method for manufacturing a composite container which can be used.

The method for producing a composite container of the present invention
The process of preparing a preform made of plastic material and
The process of preparing plastic parts and
The process of heating the preform and
The process of fitting the preform into the plastic member,
The process of heating preforms and plastic parts and inserting them into blow molding dies,
A step of expanding the preform and the plastic member as a unit by performing blow molding on the preform and the plastic member after heating.
It is characterized by including.

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

In the above aspect, it is preferable that the heating temperature of the preform in the preform heating step is 70 ° C. or higher and 120 ° C. or lower.

In the above aspect, the temperature of the preform in the step of heating the preform and the plastic member and inserting it into the blow molding die is preferably 80 ° C. or higher and 135 ° C. or lower.

In the above aspect, the heating temperature of the plastic member in the step of heating the preform and the plastic member and inserting it into the blow molding die is preferably 80 ° C. or higher and 180 ° C. or lower.

According to the present invention, a composite container having a good appearance can be obtained by blowing molding to satisfactorily expand the preform and the plastic member without causing defects such as air bubbles on the surface of the plastic member. Obtainable.

FIG. 1 is a partial vertical sectional view of a composite container 10A manufactured by the method according to the present invention. FIG. 2 is a horizontal sectional view taken along 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 cross-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 manufacturing the plastic member 40a. FIG. 9 is a schematic view showing an embodiment of a method for manufacturing the plastic member 40a. FIG. 10 is a diagram showing the shape of the thermocompression-bonded margin portion. FIG. 11 is a schematic view showing a manufacturing method of the composite container 10A.

Method for Manufacturing Composite Container 10A The method for manufacturing the composite container 10A according to the present invention is as follows.
The process of preparing the preform 10a made of plastic material and
The process of preparing the tubular plastic member 40a and
The process of heating the preform 10a and
The process of fitting the preform 10a into the plastic member 40a,
The process of heating the preform 10a and the plastic member 40a and inserting them into the blow molding die, and
The process includes a step of integrally expanding the preform 10a and the plastic member 40a by performing blow molding on the preform 10a and the plastic member 40a after heating.
Further, in the method of the present invention, if desired, after the step of fitting the preform 10a into the plastic member 40a, and before the step of heating the preform 10a and the plastic member 40a and inserting them into the blow molding die, the plastic The step of heating the manufacturing member 40a and bringing it into close contact with the preform 10a is included.

Composite container 10A
As shown in FIG. 1, the composite container 10A obtained by the method of the present invention comprises 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
Of 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, and a body portion 20 provided below the shoulder portion 12. It is provided with a bottom portion 30 provided below the body portion 20. In addition, in this specification, "upper" and "lower" mean the upper part and the lower part in the state (FIG. 1) in which the composite container 10A is upright, 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 tapping 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. Further, the shoulder portion 12 is located between the neck portion 13 and the body portion 20, and has a shape in which the diameter gradually increases from the neck portion 13 side to the body portion 20 side.

Further, the body portion 20 has a cylindrical shape having 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 tubular shape such as a quadrangular tubular shape or an octagonal tubular shape. Alternatively, the body portion 20 may have a tubular shape having a non-uniform horizontal cross section from the upper side to the lower side. Further, in the present embodiment, the body portion 20 is not formed with irregularities and has a substantially flat surface, but the present invention is not limited to this. For example, the body portion 20 may have irregularities such as panels or grooves.

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

Further, the thickness of the container body 10 in the body portion 20 is not limited to this, but can be reduced to, for example, about 50 μm to 250 μm. Further, the weight of the container body 10 is not limited to this, but can be, for example, 10 g to 20 g when the content of the container body 10 is 500 mL. By reducing the wall thickness of the container body 10 in this way, the weight of the container body 10 can be reduced.

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

A thin-film 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 in order to enhance the barrier property of the container.

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

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 in a state where it does not easily move or rotate. Further, 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 providing the plastic member 40a so as to surround the outside of the preform 10a as described later, bringing it into close contact with the outside of the preform 10a, and then biaxially stretching blow molding together with the preform 10a. Obtainable.

As shown in FIG. 1, the plastic member 40 can be provided so as to cover the shoulder portion 12, the body 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 body portion 20, and the bottom portion 30 of the container body 10.

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

Further, the thickness of the plastic member 40 is not limited to this, but can be, for example, about 5 μm to 50 μm when attached to the container body 10.

Further, since the plastic member 40 is not welded or adhered to the container body 10, it can be separated (peeled) 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 off using a knife or the like, or a cutting line is provided in advance on the plastic member 40 and along the cutting line. 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 above method, the colorless and transparent container body 10 can be recycled as in the conventional case.

Step of 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 11a corresponds to the mouth portion 11 of the container body 10 described above, and has substantially the same shape as the mouth portion 11. Further, the body portion 20a corresponds to the neck portion 13, the shoulder portion 12 and the body portion 20 of the container body 10 described above, and has a substantially cylindrical shape. The bottom portion 30a corresponds to the bottom portion 30 of the container body 10 described above, and has a substantially hemispherical shape.

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

Further, by producing the multi-layer preform 10a having two or more layers by injection molding, the container body 10 can be made into a multi-layer molded bottle having two or more layers.
For example, the intermediate layer contains 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 multi-layer molded bottle having gas barrier properties, light-shielding properties, and the like can be obtained by molding a preform 10a composed of three or more layers and then blow-molding the layers. As the intermediate layer, a resin or the like blended with the above-mentioned various resins may be used.
In addition to the preform 10a produced as described above, a commercially available product may be used.

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

Steps for Preparing the Plastic Member 40a In one embodiment, as shown in FIG. 4A, the plastic member 40a has a tubular shape (bottomed cylindrical shape), and has a cylindrical body 41 and a body. It may have 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 body portion 20 when the composite container 10A is used. be able to.
Further, in another embodiment, as shown in FIG. 4B, the plastic member 40a may have a tubular shape (bottomless cylindrical shape) as a whole and may have a cylindrical body portion 41. ..
In still another embodiment, as shown in FIGS. 4 (c) and 4 (d), the plastic member 40a is made by forming a film into a tubular shape and pasting the ends thereof. There may be. In this case, as shown in FIG. 4 (c), the plastic member 40a may be formed in a tubular shape (bottomless cylindrical shape) having a body portion 41, and as shown in FIG. 4 (d). A bottomed cylindrical shape may be formed by laminating the bottom portions 42.
Further, the plastic member 40a may or may not have heat shrinkage, but from the viewpoint of adhesion to the preform 10a, it shall have heat shrinkage. Is preferable.

Further, the length of the plastic member 40a is longer than that of the preform 10a, and as shown in FIG. 5, it is preferable to have a margin portion 80a at one end thereof. The length of the margin 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 a margin portion 80a, the bottom portion 30a can be formed by the thermocompression bonding step described later even if the shape of the plastic member 40a is tubular.
The length of the heat-shrinkable plastic member 40a means the length X including the margin portion 80a, as shown in FIG. Further, the length of the preform 10a means the length Y from the neck portion 13a to the bottom portion 30a, as shown in FIG.

The plastic member 40a includes, 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, methyl polyacrylate, polyacrylonitrile, polyacrylamide, polybutadiene, polybutene-1, polyisoprene, polychloroprene, ethylenepropylene rubber, Butyl rubber, nitrile rubber, acrylic rubber, silicone rubber, fluororubber, nylon 6, nylon 6,6, MXD6, aromatic polyamide, polycarbonate, ethylene polyterephthalate, butylene polyterephthalate, ethylene polynaphthalate, U polymer, liquid crystal polymer , Modified polyphenylene ether, polyether ketone, polyether ether ketone, unsaturated polyester, alkyd resin, polyimide, polysulfone, polyphenylene sulfide, polyether sulfone, silicone resin, polyurethane, phenol resin, urea resin, polyethylene oxide, polypropylene oxide, polyacetal , An epoxy resin, an ionomer resin, and the like can be produced using a resin material.
Of these, it is preferable to include a thermoplastic inelastic resin such as PE, PP, PET, or PEN.
Further, the resin material may contain a copolymer in which two or more monomer units constituting the above resin are polymerized. Further, the resin material may contain two or more of the above-mentioned resins.

Further, the plastic member 40a may be composed of a single layer or a multilayer.
When the plastic member 40a is composed of multiple layers, for example, the layer structure of the innermost surface and the outermost surface may be the same or different.
Specific layer configurations include those with low density PE / adhesive layer / EVOH / adhesive layer / low density PE, PP / adhesive layer / EVOH / adhesive layer / PP, etc. from the innermost surface.
Examples of the adhesive constituting the adhesive layer in this case include a polyvinyl acetate adhesive, a polyacrylic acid ester adhesive, a cyanoacrylate adhesive, an ethylene copolymer adhesive, a cellulose adhesive, and a polyester adhesive. Examples thereof include adhesives, polyamide-based adhesives, polyimide-based adhesives, amino-resin-based adhesives, phenol-resin-based adhesives, epoxy-based adhesives, polyurethane-based adhesives, rubber-based adhesives, and silicone-based adhesives.

Further, the plastic member 40a may contain 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 blended material as the preform 10a, the gas barrier property of the composite container 10A is enhanced, oxygen intrusion into the container is prevented, 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 prevent the content from being reduced.
For example, in the container main body 10, a plastic member 40 may be provided in the entire area of the shoulder portion 12, the neck portion 13 and the body portion 20 and a part of the bottom portion 30 to enhance the gas barrier property of this portion.
As such a material, PE, PP, MXD-6, PGA, EVOH, PEN, or an oxygen absorber such as a fatty acid salt may be mixed with these materials.
When the plastic member 40a is composed of multiple layers, it may be provided with a layer made of a material having a gas barrier property.

Further, the plastic member 40a may contain a material having a light ray barrier property such as ultraviolet rays.
In this case, it is possible to enhance the light barrier property of the composite container 10A and prevent the content liquid 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, in the container body 10, a plastic member 40a may be provided on the entire area of the shoulder portion 12, the neck portion 13, the body portion 20, and a part of the bottom portion to enhance the ultraviolet barrier property of this portion.
As such a material, a resin material containing two or more kinds of the above-mentioned resins, or a material obtained by adding a light-shielding resin to PET, PE, or PP can be considered. Further, a foaming member having a foam cell diameter of 0.5 to 100 μm, which is produced by mixing an inert gas (nitrogen gas, argon gas) with the melt of the thermoplastic resin, may be used.
When the plastic member 40a is composed of multiple layers, it may be provided with a layer made of a material having a light ray barrier property.

Further, the plastic member 40a may contain a material having higher heat retention or cold retention (material having lower thermal conductivity) than the 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. As a result, the heat retention or cold retention of the composite container 10A is enhanced.
For example, the plastic member 40 may be provided on all or part of the body 20 of the container body 10 to improve the heat retention or cold retention 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. As such a material, foamed polyurethane, polystyrene, PE, PP, phenol resin, polyvinyl chloride, urea resin, silicone, polyimide, melamine resin and the like can be considered.
When the plastic member 40a is composed of multiple layers, it may be provided with a layer made of a material having high heat retention or cold retention (material having low thermal conductivity).
Further, it is preferable to mix hollow particles with the resin material containing these resins. The average particle size of the hollow particles is preferably 1 to 200 μm, more preferably 5 to 80 μm. Further, the hollow particles may be organic hollow particles composed of resin or the like, or inorganic hollow particles composed of glass or the like, but are organic because of their excellent dispersibility. Hollow particles are preferred. Examples of the resin constituting the organic hollow particles include a styrene resin such as a crosslinked styrene-acrylic resin, a (meth) acrylic resin such as acrylonitrile-acrylic resin, a phenol resin, a fluorine resin, a polyamide resin, and a polyimide. Examples thereof include based resins, polycarbonate resins, and polyether resins. In addition, Low Pay HP-1055, Low Pay HP-91, Low Pay OP-84J, Low Pay Ultra, Low Pay SE, Low Pay ST (manufactured by Roam and Hearth Co., Ltd.), Nipole MH-5055 (manufactured by Nippon Zeon Corporation), SX878 , SX866 (manufactured by JSR Corporation) and other commercially available hollow particles can also be used.
When the plastic member 40a is composed of a single layer, the content of the hollow particles is preferably 0.01 to 50 parts by mass with respect to 100 parts by mass of the resin material contained in the plastic member 40a. More preferably, it is ~ 20 parts by mass. When the plastic member 40a is composed of multiple layers, it is preferably 0.01 to 50 parts by mass with respect to 100 parts by mass of the resin material contained in the layer of the plastic member 40a containing hollow particles. More preferably, it is ~ 20 parts by mass.

Further, the plastic member 40a may contain a material that is less slippery than the plastic material constituting the preform 10a.
In this case, the user can easily grip the composite container 10A 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 to make the body 20 easier to hold.
When the plastic member 40a is composed of multiple layers, it may be provided with a layer made of a material that is less slippery than the plastic material constituting 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 an image or characters on the composite container 10A without separately attaching a label or the like to the container body 10 after blow molding.
For example, a plastic member 40 may be provided on all or part of the body 20 of the container body 10, and an image or characters may be displayed on the body 20.
Printing can be performed by, for example, 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 inkjet method is used, a UV curable ink is applied to the plastic member 40a (40), UV irradiation is performed on the plastic member 40a (40), and the ink is cured to form a print layer. This printing may be applied to the plastic member 40a before being fitted into the preform 10a, or may be applied with the plastic member 40a provided on the outside of the preform 10a. Further, printing may be applied to the plastic member 40 of the composite container 10A after blow molding.

Next, a method of manufacturing the plastic member 40a will be described. It should be noted that a commercially available member may be used instead of the plastic member 40a produced as described below.

In one embodiment, the plastic member 40a can be manufactured by molding a resin sheet containing the above-mentioned resin material and the like.
Examples of the molding method include deep drawing molding, or a method of molding a resin sheet into a tube shape and fusing or adhering its ends.
Further, the multi-layered plastic member 40a can be obtained by molding a laminated resin sheet in which two or more resin sheets are laminated via the above-mentioned adhesive.
The resin sheet may be a commercially available product, or may be produced by a conventionally known method. In the present invention, it is preferably produced by extrusion molding, and the extrusion molding is preferably carried out by a T-die method or an inflation method.

In one embodiment, the plastic member 40a is, as shown in FIG. 8A,
(1) First, the resin material 51 is heated and melted and extruded into a tube shape from the die 52 to form a tubular parison 53.
(2) Next, as shown in FIG. 8B, for example, the tubular parison 53 is sandwiched between the two-divided molds 54.
(3) Next, as shown in FIG. 8C, air is blown into the tubular parison 53 from the blowing nozzle 55, the tubular parison 53 is molded according to the mold 54, cooled, opened, and taken out. By sequentially performing this, 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 obtained plastic member 40a 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-mentioned resin material or the like is heated and melted in an extruder, and the melted resin material or the like is continuously extruded from a ring die and cooled to form an unstretched extrusion tube 1 (FIG. 9 (a)). )reference). The multi-layered plastic member 40a can be manufactured by co-extruding two or more resin materials.
One end of the extruded tube is then closed by welding or gluing one end of the unstretched extruded tube.
Further, the extruded tube 1 having one end closed is arranged 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 arranged (mounted) on the other end of the extrusion tube 1 (see FIG. 9C). At this time, it is preferable that the blow device 3 is brought into close contact with the extrusion tube 1 so that air does not leak between them.
Subsequently, the extrusion tube 1, the mold 2, and the blow device 3 are sent into 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 circulation type heating furnace may be used in order to keep the inside thereof at a uniform temperature. Alternatively, the extrusion tube 1, the mold 2, and the blow device 3 may be heated by passing through the heated liquid.
Next, the extrusion tube 1, the mold 2, and the blow device 3 are taken out from the heating furnace 4, and air is blown into the extrusion tube 1 from the blow device 3 to pressure-stretch the inner surface of the extrusion tube 1. As a result, the extrusion tube 1 expands and the diameter is expanded along the inner surface shape of the mold 2 (see FIG. 9E).
Then, the extrusion tube 1 is cooled in cold water while the air is ejected from the blow device 3, and the extrusion 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)).

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

Heating Step of Preform 10a The method of the present invention comprises a step of heating the preform 10a. By heating the preform 10a before fitting it 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 work 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, and is not the irradiation temperature of infrared rays, warm air, or the like.
The heating time of the preform 10a is preferably 5 seconds or more and 300 seconds or less, and more preferably 8 seconds or more and 90 seconds or less, 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 better.

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

Step 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 shrinkage, after fitting, the plastic member 40a is heated and brought into close contact with the preform 10a. The 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, and is not the irradiation temperature of infrared rays, warm air, or the like.
The heating time of the plastic member 40a is preferably 2 seconds or more and 30 seconds or less, and more preferably 5 seconds or more and 15 seconds or less, 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 better.

Step of thermocompression bonding the margin 80a of the plastic member 40a In the method of the present invention, when the plastic member 40a has a tubular shape as shown in FIG. 4B, the fitting step or the plastic member 40a is performed. After the step of heating and bringing the plastic member into close contact with the preform 10a, a step of thermocompression bonding the margin portion 80a of the plastic member 40a may be included.
The method of thermocompression bonding is not particularly limited, and is not particularly limited as long as it can be crimped by sandwiching a margin heated by infrared rays, warm air, etc. For example, it is made of metal or has heat resistance. Resin instruments (hereinafter, sometimes referred to as “crimping instruments”) can be used, and they may be combined.

Further, the shape of the margin portion 80a after thermocompression bonding is not particularly limited, and can be any shape as shown in FIG.

The surface of the crimping tool may be flat, or may have an uneven shape in part or in whole.

The crimping tool may have a heating mechanism on its surface. As a result, the crimping strength of the margin portion 80a can be further increased. The heating temperature of the surface of the crimping tool is preferably 100 ° C. or higher and 250 ° C. or lower, for example. Further, from the viewpoint of maintaining a good appearance of the surface of the plastic member 40a, the crimping time is preferably 5 seconds or less.

The pressure at the time of crimping is preferably 50 N / cm ² or more and 1000 N / cm ² or less, and 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 crimping is preferably 80 ° C. or higher and 200 ° C. or lower, although it depends on the material.

Further, the margin 80a after thermocompression bonding may be cut to an appropriate length if desired. By cutting the margin portion to an appropriate length (for example, about 2 mm), the appearance of the bottom portion when made into a composite container is improved.

Heating and Blow Molding Steps for Preform 10a and Plastic Member 40a The preform 10a and plastic member 40a are heated by the heating device 51 as shown in FIG. 11A.
In one embodiment, the preform 10a and the plastic member 40a are uniformly 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 the irradiation temperature of infrared rays, warm air, or the like.
The heating time of the preform 10a and the plastic member 40a is preferably 0.5 seconds or more and 60 seconds or less, and 2 seconds or more and 20 seconds or less, although it depends on the heating device used and the operating temperature. More preferably. By setting the heating time within the above numerical range, it is possible to prevent the plastic member 40a from being excessively heated and causing defects such as air bubbles on the surface thereof.
Further, the heating of the preform 10a and the plastic member 40a is preferably performed before the temperature of the preform 10a heated by the step of heating the preform 10a alone decreases, and the preform 10a and the plastic according to this step are preferably heated. The temperature of the preform 10a immediately before heating the manufacturing member 40a is preferably 65 ° C. or higher, and more preferably 75 ° C. or higher. Further, after the step of heating the preform 10a alone, it is preferable that the heating by this step is performed within 60 seconds, and more preferably within 40 seconds.

After heating, the preform 10a and the plastic member 40a are sent to the blow molding die 50 (see FIG. 11B). As the blow molding die, conventionally known ones can be used.
In one embodiment, the blow molding die 50 includes a pair of body molds 50a and 50b that are separated from each other and a bottom mold 50c (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 was lowered, the pair of body molds 50a and 50b were closed and sealed by the pair of body molds 50a and 50b and the bottom mold 50c. The blow molding die 50 is configured.

In the blow molding die 50, air is press-fitted into the preform 10a, and the preform 10a and the plastic member 40a are subjected to biaxial stretch blow molding, whereby the composite container 10A is obtained.
At the time of 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.
By integrally blow molding the preform 10a and the plastic member 40a in the blow molding die 50, these are shaped into a shape corresponding to the inner surface of the blow molding die 50.
Next, as shown in FIG. 11D, the pair of body molds 50a and 50b and the bottom mold 50c are separated from each other, and the composite container 10A is taken out from the blow molding mold 50.

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

(Step of preparing the plastic member 40a)
The polyolefin resin was melted and extruded from a ring-shaped die. Next, the inner surface of the extruded tube was pressurized, or the outer surface of the tube was negatively pressured from the inner surface to increase the diameter, and a heat-shrinkable plastic member 40a having an inner diameter of 27 mm as shown in FIG. 4B was produced.

(Step of heating 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.

(Matching process)
The preform 10a was manually fitted into the plastic member 40a.

(Step of heating the plastic member 40a and bringing it into close contact with the preform 10a)
After 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 heat-shrinked to be brought into close contact with the preform 10a. The heating time was 8 seconds.

(Manufacturing of composite container)
Next, the preform 10a and the plastic member 40a were heated to 100 ° C. using an infrared heater and conveyed to the blow molding die shown in FIG. 11B. 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 fitting were blow molded to obtain a composite container 10A having a full filling capacity of 500 mL. The surface of the composite container 10A did not show any defects such as air bubbles, and its appearance was good. The heating time was 5 seconds. Further, the time required from the step of heating the preform 10a to the main step was 30 seconds.

<Comparative example 1>
Using an injection molding machine, a PET preform 10a shown in FIG. 7 was produced. The weight of this preform 10a was 23.8 g.
The polyolefin resin was melted and extruded from a ring-shaped die. Next, the inner surface of the extruded tube was pressurized, or the outer surface of the tube was negatively pressured from the inner surface to increase the diameter, and a heat-shrinkable plastic member 40a having an inner diameter of 27 mm as shown in FIG. 4B was produced.
Unlike the first embodiment, the preform 10a was manually fitted without heating the preform 10a.
After 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 heat-shrinked to be brought into close contact with the preform 10a. The heating time was 8 seconds.
Next, the preform 10a and the plastic member 40a were heated to 100 ° C. using an infrared heater and conveyed to the blow molding die shown in FIG. 11B. 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 fitting were blow molded to obtain a composite container 10A having a full filling capacity of 500 mL. Bubbles were generated on the surface of the composite container 10A, and the appearance was not good. The heating time of the preform 10a and the plastic member 40a was 25 seconds.

Claims (5)

The process of preparing a preform made of plastic material and
The process of preparing plastic parts and
The step of heating the preform and
After heating the preform, the step of fitting the preform into the plastic member and
A step in which the plastic member into which the preform is fitted has a margin and the margin is thermocompression bonded.
A step of heating the preform and the plastic member and inserting them into a blow molding die.
A step of expanding the preform and the plastic member as a unit by performing blow molding on the preform and the plastic member after heating.
A method for producing a composite container, which comprises. After the step of fitting the preform into the plastic member, and before the step of heating the preform and the plastic member and inserting the preform into the blow molding die, 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 the heating temperature of the preform in the heating step of the preform is 70 ° C. or higher and 120 ° C. or lower. According to any one of claims 1 to 3, the temperature of the preform in the step of heating the preform and the plastic member and inserting the plastic member into the blow molding die is 80 ° C. or higher and 135 ° C. or lower. The method described. Any one of claims 1 to 4, wherein the heating temperature of the plastic member in the step of heating the preform and the plastic member and inserting the plastic member into the blow molding die is 80 ° C. or higher and 180 ° C. or lower. The method described in the section.