HK1262630B - Composite preform, method for producing same, composite container, method for producing said composite container, and heat shrinkable plastic member - Google Patents

Description

Composite preform and method for manufacturing the same, composite container and method for manufacturing the same, and heat-shrinkable plastic part

Technical Field

The present invention relates to a composite preform and a method for producing the same, a composite container and a method for producing the same, and a heat-shrinkable plastic component.

Background Art

Recently, bottles for storing liquid contents such as food and drinks are generally made of plastic, and the liquid contents are stored in such plastic bottles.

Such a plastic bottle containing a content liquid is produced by inserting a preform into a mold and performing biaxial stretch blow molding.

Furthermore, in conventional biaxial stretch blow molding, a preform made of a single-layer material, a multilayer material, or a blend of materials, such as PET or PP, is molded into a container shape. However, conventional biaxial stretch blow molding typically involves simply molding the preform into the container shape. Consequently, there are limited options for imparting various functions or properties (such as barrier properties and heat retention) to the container, such as by modifying the preform's material. In particular, it is difficult to impart different functions and properties to different parts of the container (such as the body or bottom).

To address this issue, the present inventors have proposed a composite container endowed with various functions and characteristics, such as light-shielding properties, a composite preform used in manufacturing the composite container, and a method for manufacturing the same (see International Publication No. 2014/208746). On the other hand, when manufacturing such a composite container, heat-shrinkable plastic parts are sometimes used as plastic parts. When heat-shrinkable plastic parts are used, it is desirable to improve the appearance and light-shielding properties of the composite container, particularly the bottom.

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

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2015-128858

Patent Document 2: International Publication No. 2014/208746

The composite container disclosed in Japanese Patent Application Laid-Open No. 2015-128858 is obtained by blow molding a composite preform comprising a container body and a plastic component. The following findings were obtained: the plastic component of the composite preform is a heat-shrinkable plastic component, which is preferred from the perspective of adhesion with the preform and, in turn, the container body. However, it is difficult to completely cover the bottom of the preform (container body) and to impart various functions, such as improved light-shielding properties, to the bottom.

The present invention has been completed based on the above findings, and its object is to provide a method for manufacturing a composite preform having a heat-shrinkable plastic member that can cover the bottom of the preform and is not damaged by blow molding during the manufacture of a composite container.

The present inventors have discovered that by thermocompression-bonding one end of a plastic component included in a composite preform, a composite preform can be produced that includes a heat-shrinkable plastic component that covers the bottom of the preform and is not damaged by blow molding during composite container production. Furthermore, the inventors have discovered that thermocompression-bonding along the shape of the preform's bottom prevents the formation of bubbles, improving the adhesion between the blow-molded plastic component and the container body and its appearance. The present invention is based on this discovery.

The present invention has been completed in view of the above-mentioned background technology, and its purpose is to provide a composite preform that can manufacture a composite container having a plastic part that will not be damaged during blow molding and can cover the bottom of the container body, and the composite preform does not generate bubbles between the plastic part and the container body during blow molding.

The present inventors have discovered that by thermocompression-bonding one end of a heat-shrinkable plastic member into which a preform is embedded, followed by twisting, a composite container can be produced in which the bottom of the container body is completely covered by the plastic member. Furthermore, the present inventors have discovered that, compared to composite containers produced by methods that include only a thermocompression bonding step without a twisting step, composite containers produced by methods that include the twisting step effectively prevent the generation of bubbles between the container body and the plastic member caused by blow molding, and also prevent damage such as delamination of the thermocompression bonded portion during blow molding.

Therefore, an object of the present invention is to provide a method for manufacturing a composite preform, which is a method for manufacturing a composite preform used in the manufacture of a composite container having a container body and a plastic component that can completely cover the bottom of the container body. The method for manufacturing a composite preform can prevent the generation of bubbles between the container body and the plastic component and the breakage of the hot pressing portion caused by blow molding.

Another object of the present invention is to provide a composite preform and a method for producing the same, a composite container and a method for producing the same, and a heat-shrinkable plastic part that can improve the appearance of a composite container, particularly a bottom.

Summary of the Invention

The method for manufacturing a composite preform of the present invention is characterized in that it comprises: a process of preparing a preform made of a plastic material, wherein the preform has a mouth, a main body connected to the mouth, and a bottom connected to the main body; a process of preparing a tubular heat-shrinkable plastic component, wherein the heat-shrinkable plastic component has a blank portion for heat-compression bonding at one end and is longer than the main body and the bottom of the preform; a process of embedding the preform into the plastic component; a process of causing the plastic component to heat-shrink by heating the preform and the plastic component; and a process of heat-compression bonding the blank portion of the plastic component.

In the above aspect, preferably, the margin portion includes a first opposing surface and a second opposing surface disposed to face each other, and a portion of the first opposing surface and a portion of the second opposing surface are in pressure contact with each other.

In the above aspect, it is preferable that the first opposing surface and the second opposing surface are press-contacted with each other while being offset in the axial direction of the plastic member.

In the above embodiment, the length of the blank portion is preferably 3 mm or more.

In the above aspect, the thermal compression bonding of the margin portion is preferably performed using a tool having a flat surface or an uneven surface.

In the above aspect, the surface temperature of the device is preferably 100° C. or higher and 250° C. or lower.

In the above embodiment, the pressure during thermocompression bonding of the blank portion is preferably 50 N/cm ² or more and 1000 N/cm ² or less.

In the above embodiment, the temperature of the heat-shrinkable plastic member during thermocompression bonding of the blank portion is preferably 80° C. or higher and 200° C. or lower.

The method for manufacturing a composite container of the present invention is characterized in that it comprises: a step of heating the composite preform obtained by the above method and inserting it into a blow molding mold; and a step of blow molding the heated composite preform to integrate the preform and the plastic component and expand them.

The composite preform of the present invention is characterized in that it comprises: a preform having a mouth, a main body connected to the above-mentioned mouth, and a bottom connected to the above-mentioned main body; and a heat-shrinkable plastic component, which is arranged in a manner to surround the outside of the above-mentioned preform, has a blank portion for thermocompression bonding at one end, and is longer than the length of the above-mentioned main body and the above-mentioned bottom of the above-mentioned preform, and the above-mentioned blank portion of the above-mentioned plastic component is thermocompression bonded.

In the above aspect, preferably, the margin portion includes a first opposing surface and a second opposing surface disposed to face each other, and a portion of the first opposing surface and a portion of the second opposing surface are in pressure contact with each other.

In the above aspect, it is preferable that the first opposing surface and the second opposing surface are press-contacted with each other while being offset in the axial direction of the plastic member.

The composite container of the present invention is a blow-molded product of the above-mentioned composite preform, and is characterized in that it comprises: a container body, the container body having a mouth, a main body arranged below the above-mentioned mouth, and a bottom arranged below the above-mentioned main body; and a heat-shrinkable plastic component, the heat-shrinkable plastic component is tightly arranged to the outside of the above-mentioned container body, and the above-mentioned blank portion of the above-mentioned plastic component is heat-pressed.

According to the present invention, there is provided a method for producing a composite preform including a heat-shrinkable plastic member that can cover the bottom of the preform and is not damaged by blow molding during production of a composite container.

The composite preform of the present invention is characterized in that it comprises: a preform having a mouth, a main body connected to the above-mentioned mouth, and a bottom connected to the above-mentioned main body; and a heat-shrinkable plastic component, which is arranged in a manner to surround the outside of the above-mentioned preform, and the end of the above-mentioned plastic component on the bottom side of the above-mentioned preform is crimped along the shape of the bottom of the above-mentioned preform to form a crimped bottom.

The composite container of the present invention is a blow-molded product of the above-mentioned composite preform, and is characterized in that it comprises: a container body, the container body having a mouth, a main body arranged below the above-mentioned mouth, and a bottom arranged below the above-mentioned main body; and a heat-shrinkable plastic component, the heat-shrinkable plastic component is tightly arranged to the outer side of the above-mentioned container body, and one end of the above-mentioned plastic component on the above-mentioned bottom side of the above-mentioned container body is crimped to form a crimped bottom.

The method for manufacturing a composite preform of the present invention is characterized in that it includes: a process of preparing a preform, wherein the preform has a mouth, a main body connected to the mouth, and a bottom connected to the main body; a process of preparing a tubular heat-shrinkable plastic component, wherein the heat-shrinkable plastic component is longer than the main body and the bottom of the preform; a process of embedding the preform in the plastic component; a process of causing the plastic component to heat shrink by heating the preform and the plastic component; and a process of forming a pressed bottom by hot-pressing the end of the plastic component on the bottom side of the preform along the shape of the bottom of the preform.

In the above embodiment, the thermocompression bonding is preferably performed using a tool having a flat surface or an uneven surface.

In the above aspect, the surface temperature of the device is preferably 100° C. or higher and 250° C. or lower.

In the above embodiment, the pressure during the thermocompression bonding is preferably 50 N/cm ² or more and 1000 N/cm ² or less.

In the above embodiment, the temperature of the heat-shrinkable plastic member during the thermocompression bonding is preferably 80° C. or higher and 200° C. or lower.

The above embodiment preferably further comprises a cutting step, wherein the preform is cut so that the length of the portion from the top of the bottom of the preform to the end of the plastic member is 0.5 mm to 5 mm.

In the above embodiment, the length of the plastic member is preferably greater than the sum of the lengths of the main body and the bottom of the preform by 3 mm or more and 25 mm or less.

According to the present invention, a composite preform and a method for manufacturing the same can be provided, wherein the composite preform can be used to manufacture a composite container having a plastic component that will not break during blow molding and can cover the bottom of the container body, and the composite preform does not generate bubbles between the plastic component and the container body during blow molding.

Furthermore, a composite container that can be produced by blow-molding the composite preform can be provided.

The method for manufacturing a composite preform of the present invention is characterized in that it comprises: a process of preparing a preform, wherein the preform has a mouth, a main body connected to the mouth, and a bottom connected to the main body; a process of preparing a tubular heat-shrinkable plastic component, wherein the heat-shrinkable plastic component has a blank portion for heat-compression bonding at one end; a process of embedding the preform into the plastic component; a process of heating the plastic component to cause the plastic component to heat-shrink; a process of heat-compression bonding the blank portion of the plastic component; and a process of twisting the heat-compressed blank portion to form a twisted portion.

In the above aspect, the thermal compression bonding of the margin portion is preferably performed using a tool having a flat surface or an uneven surface.

In the above aspect, the surface temperature of the device is preferably 100° C. or higher and 250° C. or lower.

In the above embodiment, the pressure during thermocompression bonding of the margin portion is preferably 50 N/cm ² or more and 1000 N/cm ² or less.

In the above embodiment, the temperature of the heat-shrinkable plastic member during thermocompression bonding of the blank portion is preferably 80° C. or higher and 200° C. or lower.

In the above aspect, it is preferable that the step of forming the twisted portion is performed by twisting off the blank portion after thermocompression bonding.

In the above embodiment, it is preferable that the step of thermocompression bonding the margin portion and the step of forming the twisted portion are performed simultaneously.

In the above embodiment, the length of the blank portion is preferably 3 mm or more.

The method for manufacturing a composite container of the present invention is characterized by comprising: a step of inserting a composite preform into a blow molding die while heating it; and a step of blow molding the heated composite preform to integrate the preform and a plastic component and expand them.

The composite preform of the present invention is characterized in that it comprises: a preform having a mouth, a main body connected to the above-mentioned mouth, and a bottom connected to the above-mentioned main body; and a heat-shrinkable plastic component, which is arranged in a manner to surround the outside of the above-mentioned preform and has a blank portion for hot pressing at one end, and the above-mentioned blank portion of the above-mentioned plastic component is hot pressed and twisted to form a twisted portion.

The composite container of the present invention is a blow-molded product of the above-mentioned composite preform, and is characterized in that it comprises: a container body, the container body having a mouth, a main body arranged below the above-mentioned mouth, and a bottom arranged below the above-mentioned main body; and a heat-shrinkable plastic component, the heat-shrinkable plastic component is tightly arranged with the outer side of the above-mentioned container body.

According to the method of the present invention, it is possible to provide a composite preform capable of producing a composite container including a container body and a plastic member capable of completely covering the bottom of the container body.

Furthermore, a composite container obtained using this composite preform can prevent air bubbles from entering between the container body and the plastic member due to blow molding, and can also prevent the blank portion bonded by thermocompression from being damaged due to blow molding.

The present invention is a method for manufacturing a composite preform, characterized in that the method for manufacturing a composite preform comprises: a process of preparing a preform made of a plastic material, wherein the preform has a mouth, a main body and a bottom; a process of preparing a heat-shrinkable plastic component, wherein the heat-shrinkable plastic component is a tubular heat-shrinkable plastic component having one end and the other end, and a first cutout portion and a second cutout portion are respectively formed at mutually opposite positions of the one end; a process of slowly inserting the heat-shrinkable plastic component relative to the preform from the other end side; and a process of making the heat-shrinkable plastic component tightly fit the outer side of the preform by causing the heat-shrinkable plastic component to shrink.

The present invention is a method for manufacturing a composite preform, characterized in that the method for manufacturing a composite preform comprises: a process of preparing a preform made of plastic material, wherein the preform has a mouth, a main body and a bottom; a process of preparing a heat-shrinkable plastic component; a process of slowly inserting the heat-shrinkable plastic component relative to the preform; a process of making the heat-shrinkable plastic component tightly fit the outer side of the preform by causing the heat-shrinkable plastic component to shrink; and a process of forming a first cutout and a second cutout at positions opposite to each other at one end of the open side of the heat-shrinkable plastic component.

The present invention is a method for manufacturing a composite preform, characterized in that a first piece and a second piece separated from each other by the first cut portion and the second cut portion are formed at the above-mentioned one end of the above-mentioned heat-shrinkable plastic component, and after the process of causing the above-mentioned heat-shrinkable plastic component to heat shrink, a process of pressing a part of the above-mentioned first piece and a part of the above-mentioned second piece together is provided.

In the above aspect, the pressure bonding is preferably performed using a tool having a flat surface or a concavo-convex surface.

In the above aspect, the surface temperature of the device is preferably 100° C. or higher and 250° C. or lower.

In the above embodiment, the pressure during the pressure bonding is preferably 50 N/cm ² or more and 1000 N/cm ² or less.

In the above embodiment, the temperature of the heat-shrinkable plastic member during the pressure bonding is preferably 80° C. or higher and 200° C. or lower.

The present invention is a method for manufacturing a composite container, which is characterized in that the method for manufacturing a composite container comprises: a process of making a composite preform using the above-mentioned method for manufacturing a composite preform; and a process of integrating and expanding the above-mentioned preform and the above-mentioned heat-shrinkable plastic component by blow molding the above-mentioned preform and the above-mentioned heat-shrinkable plastic component.

The present invention is a composite preform, characterized in that the composite preform comprises: a preform made of a plastic material, the preform having a mouth, a main body and a bottom; and a tubular heat-shrinkable plastic component, the heat-shrinkable plastic component being arranged in a manner to surround the outside of the preform, the heat-shrinkable plastic component having a tubular wide-diameter portion covering at least the main body of the preform, and a narrow-diameter portion extending outward from the bottom of the preform, wherein a first cutout portion and a second cutout portion are respectively formed at mutually opposing positions of the narrow-diameter portion.

The present invention is a composite preform characterized in that a first piece and a second piece separated from each other by the first cutout and the second cutout are formed in the narrow diameter portion, and a portion of the first piece and a portion of the second piece are press-bonded to each other.

The present invention is a composite container, which is a blow-molded product of the above-mentioned composite preform, and is characterized in that it comprises: a container body, the container body having a mouth, a main body and a bottom; and a heat-shrinkable plastic component, the heat-shrinkable plastic component is tightly arranged to the outside of the above-mentioned container body, and the above-mentioned heat-shrinkable plastic component is crimped at a position covering the above-mentioned bottom of the above-mentioned container body.

The present invention is a heat-shrinkable plastic component that is installed in a manner to surround the outside of a preform, and is characterized in that it has a cylindrical main body, the main body having one end and the other end, and a first cutout portion and a second cutout portion are respectively formed at positions opposite to each other at the one end.

According to the present invention, the appearance of the bottom portion, in particular, of the composite container can be improved, and the region having light-shielding properties can be expanded to the bottom portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a perspective view showing a composite preform according to a first embodiment of the present invention.

FIG2 is a partial vertical cross-sectional view showing a composite preform according to the first embodiment of the present invention.

FIG3 is a partial vertical sectional view showing the composite container according to the first embodiment of the present invention.

FIG4 is a horizontal cross-sectional view of the composite container taken along line IV-IV shown in FIG3 .

FIG. 5 is a schematic diagram illustrating one embodiment of a method for producing a heat-shrinkable plastic component.

FIG6 is a vertical cross-sectional view showing a state where the preform is embedded in a heat-shrinkable plastic member.

FIG. 7 is a front view of a heat-shrinkable plastic component.

FIG8 is a front view of the preform.

9( a ) to ( c ) are diagrams showing the shape of the blank portion after thermocompression bonding.

FIG. 10 is a schematic diagram illustrating a method for manufacturing a composite container.

FIG. 11 is a perspective view showing the bottom side of a composite preform according to a second embodiment of the present invention.

FIG. 12 is a bottom view showing a composite preform according to a second embodiment of the present invention.

FIG. 13 is a perspective view showing a step of thermocompression bonding the blank portion of the composite preform according to the second embodiment of the present invention.

FIG. 14 is a front view showing a step of thermocompression bonding the blank portion of the composite preform according to the second embodiment of the present invention.

FIG15 is a partial vertical cross-sectional view of a composite preform according to a third embodiment of the present invention.

FIG16 is a vertical cross-sectional view showing a state where the preform is embedded in a heat-shrinkable plastic member.

FIG17 is a front view of a heat-shrinkable plastic component.

FIG. 18 is a perspective view showing a crimping tool according to a third embodiment of the present invention.

FIG19 is a front view of a composite preform according to a fourth embodiment of the present invention.

20 is a front view showing a compression bonding tool having a holding portion and a rotating mechanism used for thermal compression bonding of a margin portion and formation of a twisted portion in a fourth embodiment of the present invention.

FIG21 is a partial vertical cross-sectional view showing a composite preform according to a fifth embodiment of the present invention.

FIG. 22 is a perspective view showing the bottom portion and surrounding area of a composite preform according to a fifth embodiment of the present invention.

FIG. 23 is a perspective view showing a heat-shrinkable plastic component before heat shrinkage.

24( a ) to ( g ) are schematic diagrams illustrating a method for producing a composite preform and a method for producing a composite container according to a fifth embodiment of the present invention.

FIG. 25 is a perspective view showing the bottom portion and surrounding area of a composite preform according to a modified example of the fifth embodiment of the present invention.

DETAILED DESCRIPTION

(First embodiment)

Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings. Figures 1 to 10 are diagrams showing the first embodiment of the present invention.

Composite preform 70

First, the structure of the composite preform according to the present embodiment will be described using FIG. 1 and FIG. 2 .

As shown in FIG. 1 and FIG. 2 , a composite preform 70 of the present embodiment includes a preform 10 a made of a plastic material and a substantially bottomed cylindrical heat-shrinkable plastic member 40 a provided to surround the outside of the preform 10 a .

As shown in FIG. 1 and FIG. 2 , the preform 10 a includes a mouth portion 11 a , a main body portion 20 a connected to the mouth portion 11 a , and a bottom portion 30 a connected to the main body portion 20 a .

In this case, the heat-shrinkable plastic member 40a is longer than the main body and bottom of the preform 10a. As shown by the oblique lines in FIG2 , a blank portion 80a for thermocompression bonding is formed at the end (one end) 40b of the plastic member 40a on the bottom 30a side of the preform 10a.

The blank portion 80a includes a curved surface portion 44 formed along the shape of the bottom portion 30a of the preform 10a, and a first opposing surface 46a and a second opposing surface 46b, each protruding from the curved surface portion 44. The first opposing surface 46a and the second opposing surface 46b are integrally bonded together by heat compression. When viewed from the bottom, the first opposing surface 46a and the second opposing surface 46b extend in a substantially straight line along the radial direction of the main body 20a. In this case, the first opposing surface 46a and the second opposing surface 46b are press-bonded across the entire radial direction of the main body 20a.

The composite preform 70 is subjected to biaxial stretch blow molding to integrate the preform 10a and the plastic member 40a of the composite preform 70 and expand, thereby obtaining a composite container 10A shown in FIG. 3 .

Composite container

Next, the structure of the composite container 10A of this embodiment will be described. As shown in FIG3 , the composite container 10A includes a container body 10 made of a plastic material, located inside, and a plastic member 40, which is provided in close contact with the outside of the container body 10. As will be described later, the composite container 10A is obtained by biaxially stretching and blow-molding a composite preform 70 using a blow molding die 50, thereby integrating the preform 10a and the heat-shrinkable plastic member 40a of the composite preform 70 and expanding them.

The container body 10 includes a mouth 11, a neck 13 provided below the mouth 11, a shoulder 12 provided below the neck 13, a main body 20 provided below the shoulder 12, and a bottom 30 provided below the main body 20. It should be noted that in this specification, "upper" and "lower" refer to the upper and lower parts, respectively, when the composite container 10A is in an upright position ( FIG. 3 ).

The mouth 11 has a threaded portion 14 for screwing to a cap (not shown) and a flange 17 provided below the threaded portion 14. The shape of the mouth 11 may be any known shape, such as a press-fit type.

The neck portion 13 is located between the flange portion 17 and the shoulder portion 12 and has a substantially cylindrical shape with a substantially uniform diameter. In addition, the shoulder portion 12 is located between the neck portion 13 and the main body portion 20 and has a shape with a diameter gradually increasing from the neck portion 13 side toward the main body portion 20 side.

Furthermore, the main body 20 has an overall cylindrical shape with a substantially uniform diameter. However, this is not limiting and the main body 20 may also have a polygonal cylindrical shape, such as a quadrilateral or octagonal cylindrical shape. Alternatively, the main body 20 may have a cylindrical shape with a non-uniform horizontal cross-section from top to bottom. Furthermore, in this embodiment, the main body 20 has a substantially flat surface without any concavities or convexities, but this is not limiting. For example, the main body 20 may have concavities or convexities, such as panels or grooves.

The bottom 30 has a central recess 31 and a grounding portion 32 provided around the recess 31. The shape of the bottom 30 is not particularly limited and may have any known shape (eg, a petal-shaped or round bottom).

The thickness of the container body 10 within the main body portion 20 can be set relatively thin, for example, to between 50 μm and 250 μm, but is not limited thereto. Furthermore, the weight of the container body 10 can be set to between 10 g and 20 g, for example, when the container body 10 has a capacity of 500 ml, but is not limited thereto. By reducing the wall thickness of the container body 10 in this manner, the container body 10 can be made lighter.

The container body 10 can be produced by biaxially stretching and blow-molding a preform 10 a produced by injection-molding a resin material.

In order to improve the barrier properties of the container, a vapor-deposited 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 body 10 may be, for example, a bottle having a full filling capacity of 100 ml or more and 2000 ml or less. Alternatively, the container body 10 may be a large bottle having a full filling capacity of 10 L or more and 60 L or less.

The heat-shrinkable plastic member 40 is not attached to the outer surface of the container body 10 by adhesion, but is tightly attached to the outer surface of the container body 10 in a thinly extended state and is attached in a state that does not easily move or rotate relative to the container body 10. Furthermore, as shown in FIG4 , the heat-shrinkable plastic member 40 is provided over the entire circumference of the container body 10 so as to surround the container body 10 and has a substantially circular horizontal cross-section.

The plastic member 40 (40a) is formed by surrounding the outside of the preform 10a, adhering to the outside of the preform 10a, and then biaxially stretching and blow-molding the preform 10a. The heat-shrinkable plastic member 40 is formed by integrating the tubular heat-shrinkable plastic member 40a with the preform 10a and stretching the preform 10a.

As shown in FIG3 , the plastic member 40 can be provided so as to cover the shoulder 12, main body 20, and bottom 30 of the container body 10, excluding the mouth 11 and neck 13. This configuration allows the shoulder 12, main body 20, and bottom 30 of the container body 10 to be provided with desired functions and characteristics. Alternatively, the plastic member 40 can be provided so as to cover the neck 13, shoulder 12, main body 20, and bottom 30 of the container body 10, excluding the mouth 11.

The thickness of the heat-shrinkable plastic member 40 when attached to the container body 10 can be set to, for example, 5 μm to 500 μm, more preferably 5 μm to 50 μm, but is not limited thereto.

In this embodiment, the heat-shrinkable plastic component 40 can be colored in a visible light color such as red, blue, yellow, green, brown, black, or white. In addition, the heat-shrinkable plastic component 40 can be (semi-) transparent or opaque. In this case, for example, the heat-shrinkable plastic component 40 can be colored in a visible light color, and the container body 10 can be made colorless and transparent. Alternatively, both the container body 10 and the heat-shrinkable plastic component 40 can be colored in a visible light color. It should be noted that when producing a heat-shrinkable plastic component 40 colored in a visible light color, a visible light color pigment can be added to the molding material in the process of producing the heat-shrinkable plastic component 40a by extrusion molding or the like before blow molding.

Furthermore, since the heat-shrinkable plastic member 40 is not welded or adhered to the container body 10, it can be separated (peeled) from the container body 10. The heat-shrinkable plastic member 40 can be separated (peeled) from the container body 10 by, for example, cutting the heat-shrinkable plastic member 40 with a knife or the like, or by pre-forming a cut line or notch in the heat-shrinkable plastic member 40 and peeling the heat-shrinkable plastic member 40 along the cut line or notch. Using the above method, the heat-shrinkable plastic member 40 can be separated and removed from the container body 10, allowing the colorless and transparent container body 10 to be reused as in the conventional method.

Furthermore, as shown in FIG3 , one end of the heat-shrinkable plastic member 40 on the bottom 30 side of the container body 10 is press-bonded, forming a press-bonded bottom 45A. In FIG3 , the heat-shrinkable plastic member 40 is press-bonded at a position covering the bottom 30 of the container body 10. Specifically, the heat-shrinkable plastic member 40a is heat-bonded so that the first opposing surface 46a and the second opposing surface 46b ( FIG1 ) of the heat-shrinkable plastic member 40a of the composite preform 70 described above overlap. As a result, after blow molding, the opening 48d ( FIG6 ) of the heat-shrinkable plastic member 40a is sealed, and the bottom 30 is completely covered by the heat-shrinkable plastic member 40.

Method for manufacturing composite preform

Next, a method for manufacturing the composite preform 70 according to the present embodiment will be described.

Preform preparation process

First, a preform 10a is prepared. As shown in Figures 1 and 2, the preform 10a includes a mouth 11a, a main body 20a connected to the mouth 11a, and a bottom 30a connected to the main body 20a. The mouth 11a corresponds to the mouth 11 of the container body 10 described above and has a shape roughly the same as that of the mouth 11. Furthermore, after the composite container 10A is manufactured, the mouth 11a includes a threaded portion 14a for screwing to a lid (not shown) and a flange 17a provided below the threaded portion 14a. The main body 20a corresponds to the neck 13, shoulder 12, and main body 20 of the container body 10 described 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.

The preform 10a can be manufactured by injection molding a resin material using conventionally known equipment. Preferred resin materials include thermoplastic resins, particularly PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PC (polycarbonate), and ionomer resins. Mixtures of these resins may also be used. The preform 10a may contain colorants such as red, blue, yellow, green, brown, black, and white. However, for ease of reuse, it is preferably colorless and transparent without these colorants.

Furthermore, by using injection molding to produce a multilayer preform 10a having two or more layers, the container body 10 can be a multilayer bottle having two or more layers. For example, the intermediate layer can be made of a resin (intermediate layer) having gas barrier and light-blocking properties, such as MXD6, MXD6 + fatty acid salt, PGA (polyglycolic acid), EVOH (ethylene vinyl alcohol copolymer), or PEN (polyethylene naphthalate). After forming a preform 10a having three or more layers, blow molding can be used to produce a multilayer bottle having gas barrier and light-blocking properties. It should be noted that a resin blended from the aforementioned resins can be used as the intermediate layer.

Alternatively, the container body 10 can be manufactured by mixing an inert gas (nitrogen, argon) into a thermoplastic resin melt to form a foamed preform having a foamed cell diameter of 0.5 μm to 100 μm, and then blow-molding the foamed preform. Such a container body 10 has built-in foamed cells, thereby improving the light-shielding properties of the entire container body 10.

Process for preparing a tubular heat-shrinkable plastic component

First, the heat-shrinkable plastic member 40a is prepared. In one embodiment, the tubular heat-shrinkable plastic member 40a can be produced by a method including an extrusion molding step.

More specifically, a resin material, etc., described later, is first heated and melted in an extruder, and the molten resin material, etc., is continuously extruded through a ring die and cooled to form an unstretched extruded tube 1 (see FIG. 5( a )). It should be noted that a multi-layered plastic component 40 a can be produced by co-extruding two or more resin materials.

Next, one end of the unstretched extruded tube is sealed by welding or bonding.

Furthermore, the extruded tube 1 with one end closed is placed in a die 2 having an inner diameter larger than the outer diameter of the extruded tube 1 (see FIG. 5( b )).

Next, a blow molding device 3 (see FIG5(c)) is placed (installed) at the other end of the extrusion tube 1. At this time, the blow molding device 3 is preferably in close contact with the extrusion tube 1 so that air does not leak therebetween.

Next, the extrusion tube 1, die 2, and blow molding device 3 are placed in this configuration into a heating furnace 4, where they are heated to 70-150°C (see FIG5(d)). A hot air circulation type heating furnace can be used as the heating furnace 4 to achieve a uniform temperature inside the furnace 4. Alternatively, the extrusion tube 1, die 2, and blow molding device 3 can be heated by passing them through a heated liquid.

Next, the extruded tube 1, die 2, and blow molding device 3 are removed from the heating furnace 4, and air is blown from the blow molding device 3 into the extruded tube 1, thereby pressurizing and stretching the inner surface of the extruded tube 1. This causes the extruded tube 1 to expand and expand in diameter to follow the inner surface shape of the die 2 (see Figure 5(e)).

Then, while air is being blown out of the blow molding device 3, the extruded tube 1 is cooled in cold water and removed from the extruded tube mold 2 (see FIG5(f)). This is cut into desired dimensions to obtain a tubular heat-shrinkable plastic component 40a (see FIG5(g)). It should be noted that a commercially available tubular heat-shrinkable plastic component 40a may also be used.

The heat-shrinkable plastic member 40a may include polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, poly-4-methyl-1-pentene, polystyrene, AS resin, ABS resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, ionomer resin, diallyl phthalate resin, fluorine resin, polymethyl methacrylate, polyacrylic acid, polymethyl acrylate, polyacrylonitrile, polyacrylamide, polybutadiene, poly-1-butene, polyisoprene, polychloroprene The composite container 10A is made of a resin material such as diene, ethylene propylene rubber, butyl rubber, nitrile rubber, acrylic rubber, silicone rubber, fluororubber, nylon 6, nylon 6,6, MXD6, aromatic polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, 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, phenolic resin, urea resin, polyethylene oxide, polypropylene oxide, polyacetal, and epoxy resin. Among these, polyethylene, polypropylene, and polystyrene are preferred because they can further prevent breakage from thermal compression bonding during blow molding during the manufacture of the composite container 10A. Furthermore, the resin material may comprise a copolymer formed by polymerizing monomer units constituting two or more of the above resins. Furthermore, the resin material may comprise two or more of the above resins. Furthermore, various additives may be added to the material of the heat-shrinkable plastic member 40a in addition to the main component resin, within a range that does not impair its properties. Examples of such additives include plasticizers, UV stabilizers, anti-coloring agents, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, linear friction reducers, slip agents, mold release agents, antioxidants, ion exchangers, and coloring pigments.

Furthermore, the heat-shrinkable plastic component 40a may comprise a material having gas barrier properties, such as oxygen or water vapor. In this case, the gas barrier properties of the composite container 10A can be improved, preventing oxygen from entering the container and deteriorating the liquid contents, while also preventing water vapor from evaporating from the container and reducing the container volume, without using a multilayer preform or a preform comprising a mixed material as the preform 10a. Such materials include polyethylene, polypropylene, MXD-6, PGA, EVOH, polyethylene naphthalate, or oxygen-absorbing materials such as fatty acid salts mixed with these materials. It should be noted that when the heat-shrinkable plastic component 40a is composed of multiple layers, it may include a layer composed of a material having gas barrier properties.

In addition, the heat-shrinkable plastic component 40a may include a material having light-blocking properties such as blocking ultraviolet rays. In this case, the light-blocking properties of the composite container 10A can be improved, and the content liquid can be prevented from being degraded by ultraviolet rays, etc., without using a multi-layer preform or a preform containing a mixed material as the preform 10a. As such a material, a resin material containing two or more of the above-mentioned resins, or a material in which a light-shielding resin is added to polyethylene terephthalate, polyethylene, or polypropylene can be considered. In addition, a foam component having a foaming pore diameter of 0.5 to 100 μm, which is produced by mixing an inert gas (nitrogen, argon) into a melt of a thermoplastic resin, can be used. It should be noted that when the heat-shrinkable plastic component 40a is composed of multiple layers, it can have a layer composed of a material having light-blocking properties.

Furthermore, the heat-shrinkable plastic component 40a may comprise a material with higher heat-retention or cold-retention properties (a material with lower thermal conductivity) than the plastic material comprising the preform 10a. In this case, the temperature of the liquid contents can be less likely to be transferred to the surface of the composite container 10A without increasing the thickness of the container body 10 itself. This improves the heat-retention or cold-retention properties of the composite container 10A. Examples of such materials include foamed polyurethane, polystyrene, polyethylene, polypropylene, phenolic resin, polyvinyl chloride, urea resin, silicone, polyimide, and melamine resin. It should be noted that when the heat-shrinkable plastic component 40a is constructed from multiple layers, it may include a layer composed of a material with higher heat-retention or cold-retention properties (a material with lower thermal conductivity). Furthermore, it is preferable to mix hollow particles into the resin material comprising these resins. The average particle size of the hollow particles is preferably between 1 μm and 200 μm, and more preferably between 5 μm and 80 μm. It should be noted that, " average particle size " refers to volume average particle size, and can use particle size distribution/particle size distribution measuring device (for example, Nanotrac particle size distribution measuring device, Nikkiso Co., Ltd. manufacture etc.) to utilize known method to measure.In addition, as hollow particle, can be the organic hollow particle consisting of resin etc., can also be the inorganic hollow particle consisting of glass etc., for the reason of excellent dispersibility, preferably organic hollow particle.As the resin constituting organic hollow particle, for example, can enumerate styrene resins such as crosslinked styrene-acrylic resin, (methyl) acrylic resins such as acrylonitrile-acrylic resin, phenolic resin, fluorine resin, polyamide resin, polyimide resin, polycarbonate resin, polyether resin etc. Alternatively, commercially available hollow particles such as Ropaque HP-1055, Ropaque HP-91, Ropaque OP-84J, Ropaque Ultra, Ropaque SE, and Ropaque ST (manufactured by Rohm and Haas Co., Ltd.), Nipol MH-5055 (manufactured by ZEON Japan Co., Ltd.), SX8782, and SX866 (manufactured by JSR Corporation) may be used. When the heat-shrinkable plastic component 40a is composed of a single layer, the content of the hollow particles is preferably from 0.01 parts by mass to 50 parts by mass, and more preferably from 1 part by mass to 20 parts by mass, relative to 100 parts by mass of the resin material contained in the heat-shrinkable plastic component 40a. When the heat-shrinkable plastic component 40a is composed of multiple layers, the content is preferably from 0.01 parts by mass to 50 parts by mass, and more preferably from 1 part by mass to 20 parts by mass, relative to 100 parts by mass of the resin material contained in the layer of the heat-shrinkable plastic component 40a containing the hollow particles.

The heat-shrinkable plastic member 40a may also be made of a material that is less slippery than the plastic material forming the preform 10a. In this case, the composite container 10A can be easily gripped by the user without changing the material of the container body 10. It should be noted that when the heat-shrinkable plastic member 40a is composed of multiple layers, a layer composed of a material that is less slippery than the plastic material forming the preform 10a may be included. In this case, this layer is preferably the outermost layer of the heat-shrinkable plastic member 40a.

Alternatively, the heat-shrinkable plastic member 40a can be made of the same material as the container body 10 (preform 10a). In this case, for example, the heat-shrinkable plastic member 40 can be placed in a portion of the composite container 10A where strength is to be improved, thereby selectively improving the strength of that portion. Examples of such materials include thermoplastic resins, particularly PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), and PC (polycarbonate).

The heat-shrinkable plastic member 40a is longer than the combined length of the main body 20a and bottom 30a of the preform 10a. As shown in FIG6 , it has a margin 80a at one end 40b. The margin 80a is preferably 3 mm or longer, more preferably 5 mm or longer and 20 mm or shorter. By setting the margin 80a within this range, the thermocompression bonding process can be performed more easily, the material used can be reduced, and costs can be reduced.

Note that, as shown in FIG7 , the length of the heat-shrinkable plastic member 40a refers to the length of the heat-shrinkable plastic member 40a before heat shrinkage, including the margin portion 80a, and refers to the length X of the heat-shrinkable plastic member 40a along the axial direction. Furthermore, as shown in FIG8 , the length of the preform 10a refers to the length of the main body 20a and bottom 30a of the preform 10a, excluding the mouth 11a, and refers to the length Y measured along the axial direction of the preform 10a, from the region 13a corresponding to the neck 13 to the bottom 30a.

Furthermore, a design or printing can be applied to the heat-shrinkable plastic component 40a. In this case, an image or text can be displayed on the composite container 10A without applying a separate mark to the container body 10 after blow molding. Printing can be performed by a printing method such as inkjet printing, gravure printing, offset printing, or flexographic printing. For example, when using the inkjet method, a printed layer can be formed by applying UV curable ink to the heat-shrinkable plastic component 40a (40), irradiating it with UV, and curing it. This printing can be performed on the heat-shrinkable plastic component 40a before it is embedded in the preform 10a, or it can be performed when the heat-shrinkable plastic component 40a is placed outside the preform 10a. Furthermore, printing can be performed on the heat-shrinkable plastic component 40 of the composite container 10A after blow molding. In addition, the heat-shrinkable plastic component 40a can be colored in a visible light color such as red, blue, yellow, green, brown, black, or white, and can be transparent or opaque.

Embedding process

The heat-shrinkable plastic member 40a, thus manufactured and open at both ends, is inserted into the preform 10a from one end. At this point, the heat-shrinkable plastic member 40a covers the periphery of the main body 20a and bottom 30a of the preform 10a, excluding the opening 11a. Thus, as shown in FIG6 , the preform 10a is inserted from the side of the heat-shrinkable plastic member 40a opposite to the side where the margin 80a is provided.

Heat shrink process

Next, the preform 10a and the heat-shrinkable plastic member 40a are heated, whereby the heat-shrinkable plastic member 40a is thermally shrunk and comes into close contact with the outer surface of the preform 10a.

The method for heating the preform 10a and the heat-shrinkable plastic member 40a is not particularly limited, and infrared rays, hot air, or the like can be used as appropriate. The heating temperature is preferably 60°C to 250°C, and more preferably 80°C to 150°C. It should be noted that the heating temperature refers to the surface temperature of the heat-shrinkable plastic member 40a during heating, and does not refer to the irradiation temperature of the infrared rays, hot air, or the like.

Thermal compression bonding process

Next, the blank portion 80a formed at the end (one end) 40b of the plastic component 40a opposite to the end (end on the mouth 11a side) where the preform 10a is embedded is subjected to heat compression. This heat compression can be performed by heating the compression portion using infrared rays, hot air, etc., and then clamping the above-mentioned end 40b of the plastic component 40a in the horizontal direction using a pair of compression tools (not shown). As a result, the opening 48d (Figure 6) formed in the cylindrical end 40b of the plastic component 40a is closed, and the first opposing surface 46a and the second opposing surface 46b can be heat compressed. The material of the compression tool is not particularly limited, and a compression tool made of metal or heat-resistant resin can be used. The method of hot pressing the blank portion 80a is not limited to the above method. Any method can be used as long as the blank portion heated by infrared rays, hot air, etc. is clamped and pressed. For example, metal or heat-resistant resin tools (hereinafter sometimes referred to as "pressing tools") can be used, or they can be combined.

In addition, the shape of the blank portion 80a after thermal compression bonding is not particularly limited, and can be any shape as shown in Figures 9(a) to (c).

Specifically, as shown in FIG9(a), the first opposing surface 46a and the second opposing surface 46b formed at the end 40b of the plastic member 40a can be crimped together in a substantially straight line along the radial direction of the main body 20a when viewed from the bottom. Furthermore, the end 40b of the plastic member 40a can be crimped together in a cross shape when viewed from the bottom (FIG9(b)), or the crimped portions of the end 40b can be arranged evenly spaced at approximately 120° intervals when viewed from the bottom (FIG9(c)).

The surface of the crimping tool may be flat, or may have a concave-convex shape partially or entirely.

The crimping tool may have a heating mechanism on its surface. This can further improve the crimping strength of the blank portion 80a. The heating temperature of the crimping tool surface is preferably, for example, 100°C or higher and 250°C or lower.

The pressure during compression bonding 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 during pressure bonding varies depending on the material, but is preferably 80°C or higher and 200°C or lower.

In addition, the blank portion 80a after thermocompression bonding can be cut into an appropriate length as desired. By cutting the blank portion into an appropriate length (for example, about 2 mm), the bottom appearance of the composite container is improved.

The heat-shrinkable plastic member 40a after heat shrinkage is not bonded to the outer surface of the preform 10a, and is in close contact with the preform 10a to such an extent that it does not move or rotate, or does not fall due to its own weight.

2 , after the margin 80a is crimped, the plastic member 40a becomes a bottomed cylindrical shape having a cylindrical main body 41 and a bottom 42 connected to the main body 41. In this case, the bottom 42 of the plastic member 40a covers the bottom 30a of the preform 10a, thereby enabling various functions and characteristics to be imparted to the bottom 30 in addition to the main body 20 of the composite container 10A.

Method for manufacturing composite container

The manufacturing method of the composite container of this embodiment includes: a process of heating the composite preform 70 manufactured as described above and inserting it into a blow molding mold; and a process of blow molding the heated composite preform 70 to make the preform 10a and the heat-shrinkable plastic component 40a become one and expand.

The method for producing the composite container 10A of the present invention will be described in more detail with reference to FIG. 10( a ) to FIG. 10 ( d ).

First, prepare the composite preform 70 described above. The composite preform 70 comprises a preform 10a and a heat-shrinkable plastic component 40a having a bottom and being arranged to surround the outside of the preform 10a. The plastic component 40a is heat-pressed at the blank portion 80a. Next, the composite preform 70 is heated by the heating device 51 (see FIG10(a)). At this time, the composite preform 70 is uniformly heated in the circumferential direction by the heating device 51 while being rotated with the mouth 11a facing downward. The heating temperature of the preform 10a and the plastic component 40a in this heating process can be, for example, 90°C to 130°C.

Next, the composite preform 70 heated by the heating device 51 is fed into the blow molding die 50 (see FIG. 10( b )).

The composite container 10A is molded using this blow molding die 50. In this case, the blow molding die 50 consists of a pair of separate main body molds 50a and 50b and a bottom mold 50c (see FIG10(b)). In FIG10(b), the pair of main body molds 50a and 50b are open to each other, and the bottom mold 50c is raised. In this state, the composite preform 70 is inserted between the pair of main body molds 50a and 50b.

Next, as shown in FIG10(c), after the bottom mold 50c is lowered, the pair of main body molds 50a, 50b are closed, and the pair of main body molds 50a, 50b and the bottom mold 50c form a closed blow molding mold 50. Next, air is pressed into the preform 10a to perform biaxial stretch blow molding on the composite preform 70.

Thus, the container body 10 is obtained from the preform 10a within the blow mold 50. During this time, the main body molds 50a and 50b are heated to 30°C to 80°C, and the bottom mold 50c is cooled to 5°C to 25°C. At this time, the preform 10a and the plastic component 40a of the composite preform 70 are integrated and expanded within the blow mold 50. As a result, the preform 10a and the plastic component 40a are integrated and shaped to conform to the inner surface of the blow mold 50.

In this manner, a composite container 10A including the container body 10 and the plastic member 40 provided on the outer surface of the container body 10 can be obtained.

Next, as shown in FIG. 10( d ), the pair of main body molds 50 a and 50 b and the bottom mold 50 c are separated from each other, and the composite container 10A is removed from the blow molding mold 50 .

[Example]

Hereinafter, the present embodiment will be described in further detail using examples, but the present embodiment is not limited to these examples.

(Step of Preparing Preform 10a)

An injection molding machine was used to produce a preform 10a made of PET as shown in Fig. 8. The preform 10a had a weight of 23.8 g and a length Y of 90 mm.

(Step of Preparing the Heat-Shrinkable Plastic Member 40a)

A polyolefin resin is melted and extruded from a ring-shaped die. The inner surface of the extruded tube is then pressurized, or the outer surface of the tube is expanded to a negative pressure relative to the inner surface, thereby producing a heat-shrinkable plastic component 40a. The length X of the heat-shrinkable plastic component 40a produced is 100 mm, and the length of the blank portion 80a is 10 mm.

(Embedding process)

Next, the preform 10a is manually inserted from the end of the heat-shrinkable plastic member 40a opposite to the blank portion 80a.

(Heat shrinkage and thermocompression bonding process)

After embedding, the preform 10a and the heat-shrinkable plastic member 40a were heated to 100°C using an infrared heater to cause the heat-shrinkable plastic member 40a to shrink. Subsequently, the blank portion 80a was sandwiched between metal plates heated to 100°C and thermocompression-bonded at a pressure of 300 N/ ^cm² , thereby obtaining a composite preform 70.

(Manufacture of composite containers)

The composite preform 70 obtained above was heated to 100°C using an infrared heater and transferred to the blow molding die shown in FIG10B . The composite preform 70 was blow-molded in the blow molding die to produce a composite container 10A with a full fill capacity of 500 mL. The plastic member 40 of the composite container 10A covered the bottom 30 of the container body 10, and no peeling or damage was observed at the press-bonded portion.

(Second embodiment)

Next, a second embodiment of the present invention will be described with reference to Figures 11 to 14. Figures 11 to 14 illustrate the second embodiment of the present invention. In the second embodiment shown in Figures 11 to 14, the location where the blank portion 80a is crimped differs; otherwise, the structure is essentially the same as the first embodiment described above. In Figures 11 to 14, components identical to those in the first embodiment shown in Figures 1 to 13 are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

As shown in Figures 11 and 12, in the composite preform 70 of this embodiment, a first opposing surface 46a and a second opposing surface 46b are formed in a margin portion 80a, which are arranged to face each other. The first opposing surface 46a and the second opposing surface 46b are formed into an annular shape as a whole and constitute the end portion 40b of the plastic member 40a.

In this case, a portion of the first relative surface 46a and a portion of the second relative surface 46b are crimped together. Specifically, the first crimping portion 46c located at a position roughly in the radial direction of the main body 20a in the first relative surface 46a and the second crimping portion 46d located at a position roughly in the radial direction of the main body 20a in the second relative surface 46b are thermally crimped together. As a result, the first crimping portion 46c and the second crimping portion 46d are connected to each other, and the first relative surface 46a and the second relative surface 46b are integrated. When viewed from the bottom, the first relative surface 46a and the second relative surface 46b are formed into an ∞-shaped (8-shaped) shape as a whole. Therefore, a pair of openings 48e and 48f are formed between the first relative surface 46a and the second relative surface 46b.

In this case, the first opposing surface 46a and the second opposing surface 46b are crimped together with their edges offset from each other in the vertical direction (the axial direction of the heat-shrinkable plastic member 40a). Specifically, when the first crimping portion 46c and the second crimping portion 46d are crimped together, the edge 46e of the first opposing surface 46a and the edge 46f of the second opposing surface 46b are offset from each other. In this case, the edge 46f of the second opposing surface 46b is located outside (on the side away from) the edge 46e of the first opposing surface 46a.

When manufacturing such a composite preform 70, a step of press-bonding a portion of the first opposing surface 46a and a portion of the second opposing surface 46b is performed after the step of heat-shrinking the heat-shrinkable plastic member 40a and before the step of heating the composite preform 70 using the heating device 51 ( FIG. 10( a )). Specifically, while the heat-shrinkable plastic member 40a is at a high temperature immediately after the heat-shrinking step, a tool for heat-bonding is used to sandwich the first press-bonded portion 46c of the first opposing surface 46a and the second press-bonded portion 46d of the second opposing surface 46b with the first press-bonded portion 46c facing inward, thereby press-bonding the first press-bonded portion 46c and the second press-bonded portion 46d.

Specifically, as shown in Figures 13 and 14 , the first opposing surface 46a and the second opposing surface 46b can be crimped together by sandwiching the end 40b of the plastic component 40a with a pair of crimping tools 90D and 90E. Each of the pair of crimping tools 90D and 90E has a crimping point 90F. Furthermore, crimping tool 90D is thicker than crimping tool 90E. In this case, the pair of crimping tools 90A and 90B are brought closer together from both sides of the axial direction of the plastic component 40a so that the pair of crimping points 90F sandwich the first opposing surface 46a and the second opposing surface 46b. This partially closes the opening 48d (Figure 13) formed in the cylindrical end 40b of the plastic component 40a, enabling the first opposing surface 46a and the second opposing surface 46b to be thermally crimped together. The shape of the portion formed by thermally pressing the first opposing surface 46a and the second opposing surface 46b (the shape of the first pressing portion 46c and the second pressing portion 46d viewed from the front side) may be circular, square, rectangular, rhombus, or any other shape.

Alternatively, after the heat-shrinkable plastic member 40a has cooled, the first opposing surface 46a and the second opposing surface 46b may be melt-bonded using a heated tool (not shown). Alternatively, after the heat-shrinkable plastic member 40a has cooled, the tool (not shown) may be ultrasonically vibrated to melt-bond the first opposing surface 46a and the second opposing surface 46b using the heat generated by the vibration.

Thus, according to this embodiment, when the composite preform 70 is blow-molded, the margin 80a deforms to narrow the first opposing surface 46a and the second opposing surface 46b. Therefore, after blow molding, the bottom 30 of the container body 10 and the heat-shrinkable plastic member 40 are evenly and tightly fitted, which improves the appearance of the bottom 30. Furthermore, during the blow molding process, air is simultaneously exhausted from the pair of openings 48e and 48f, thereby more effectively preventing air from remaining between the bottom 30 of the container body 10 and the heat-shrinkable plastic member 40. Furthermore, by pressing a portion of the first opposing surface 46a and a portion of the second opposing surface 46b against each other, the tight fit between the bottom 30 of the container body 10 and the heat-shrinkable plastic member 40 is further ensured, allowing the production of a high-quality composite container 10A with a good appearance and excellent light-shielding properties.

Furthermore, according to this embodiment, when the first pressing portion 46c and the second pressing portion 46d are in press-contact, the end edge 46e of the first opposing surface 46a and the end edge 46f of the second opposing surface 46b are offset from each other. This prevents the pair of openings 48e and 48f from closing during blow molding of the composite preform 70, allowing air to be easily expelled from the pair of openings 48e and 48f. This further reduces the risk of air stagnation between the bottom 30 of the container body 10 and the heat-shrinkable plastic member 40.

(Third embodiment)

Next, the third embodiment of the present invention will be described. Figures 15 to 18 illustrate the third embodiment of the present invention. The third embodiment shown in Figures 15 to 18 differs in that the end of the plastic member 40a is crimped along the shape of the bottom 30a of the preform 10a, forming a crimped bottom 45. The remaining configuration is essentially the same as the first embodiment described above. In Figures 15 to 18, components identical to those of the first embodiment shown in Figures 1 to 10 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

Composite preform 70

15 is a diagram showing a composite preform 70 of this embodiment. The composite preform 70 of this embodiment includes a preform 10a made of a plastic material and a substantially bottomed cylindrical heat-shrinkable plastic member 40a provided to surround the outside of the preform 10a.

In this case, as shown by the oblique lines in FIG. 15 , the end portion 40 b of the plastic member 40 a on the bottom side of the preform 10 a is crimped along the shape of the bottom 30 a of the preform 10 a , forming a crimped bottom 45 .

In the present embodiment, a composite container 10A can be obtained by blow molding a composite preform 70 shown in FIG. 15 .

Preform 10a

The structure of the preform 10a is the same as that shown in the first embodiment (see FIG. 1 and FIG. 2 ), and therefore detailed description thereof will be omitted here.

Heat-shrinkable plastic member 40a

As shown in FIG15 , the heat-shrinkable plastic member 40a is not bonded to the preform 10a but is provided to surround the outside thereof, and is in close contact with the preform 10a to prevent movement or rotation or to prevent it from falling due to its own weight.

Furthermore, the heat-shrinkable plastic member 40a is provided around the entire circumference of the preform 10a so as to surround it. As shown in FIG15 , one end of the heat-shrinkable plastic member 40a on the bottom 30a side of the preform 10a is thermocompression-bonded along the shape of the bottom 30a of the preform 10a, forming a compression-bonded bottom 45.

Specifically, the press-fit bottom portion 45 of the heat-shrinkable plastic member 40a includes a curved surface portion 43 formed along the shape of the bottom portion 30a of the preform 10a, and a first piece 47a and a second piece 47b, each protruding from the curved surface portion 43. The first piece 47a and the second piece 47b are integrally formed by heat-compression bonding. The first piece 47a and the second piece 47b extend substantially in a straight line along the radial direction of the main body 20a when viewed from the bottom. In this manner, the first piece 47a and the second piece 47b are press-fitted together across the entire radial direction of the main body 20a.

By thermocompression bonding one end of the heat-shrinkable plastic member 40a along the shape of the bottom 30a of the preform 10a in this manner, a composite container 10A can be obtained in which the bottom 30 of the container body 10 is covered with the plastic member 40. Furthermore, air bubbles are not generated during blow molding, and the adhesion of the plastic member 40 to the container body 10 can be improved. Furthermore, the absence of air bubbles improves the appearance of the composite container 10A.

In addition, as the material of the heat-shrinkable plastic member 40a, the same material as that described in the first embodiment can be used.

Method for manufacturing composite preform 70

Next, a method for manufacturing the composite preform 70 according to the present embodiment will be described.

The manufacturing method of the composite preform 70 of this embodiment includes: a process of preparing a preform 10a, wherein the preform 10a has a mouth 11a, a main body 20a connected to the mouth 11a, and a bottom 30a connected to the main body 20a; a process of preparing a tubular heat-shrinkable plastic component 40a, wherein the heat-shrinkable plastic component 40a is longer than the preform 10a; a process of embedding the preform 10a from one end of the plastic component 40a; a process of heating the preform 10a and the plastic component 40a to cause the plastic component 40a to shrink thermally; and a process of hot-pressing the other end of the plastic component 40a on the bottom 30a side of the preform 10a along the shape of the bottom 30a of the preform 10a.

Process of preparing preforms and heat-shrinkable plastic parts

First, the preform 10a and the heat-shrinkable plastic member 40a are prepared in the same manner as in the first embodiment.

As shown in Figure 16 , the length of the heat-shrinkable plastic member 40a is longer than the sum of the lengths of the main body 20a and the bottom 30a of the preform 10a. Specifically, the length of the heat-shrinkable plastic member 40a is preferably 3 mm to 5 mm longer than the lengths of the main body 20a and the bottom 30a of the preform 10a, and more preferably 20 mm or less. This numerical range facilitates the thermocompression bonding process, reduces the amount of material used, and ultimately reduces costs.

It should be noted that in this embodiment, as shown in FIG17 , the length of the heat-shrinkable plastic member 40a refers to the length of the heat-shrinkable plastic member 40a before heat shrinkage, and refers to the length X of the heat-shrinkable plastic member 40a along the axial direction. Furthermore, the sum of the lengths of the main body 20a and the bottom 30a of the preform 10a refers to the length of the main body 20a and the bottom 30a of the preform 10a excluding the mouth 11a, and refers to the length Y of the preform 10a along the axial direction (see FIG8 ).

Embedding process

The heat-shrinkable plastic member 40a with both ends opened in this manner is fitted into the preform 10a from one end thereof. That is, as shown in FIG16 , the preform 10a is fitted into the heat-shrinkable plastic member 40a from one end.

Heat shrink process

Next, the preform 10a and the heat-shrinkable plastic member 40a are heated, whereby the heat-shrinkable plastic member 40a is thermally shrunk and comes into close contact with the outer surface of the preform 10a.

Thermal compression bonding process

Next, the end (the other end) 40b of the plastic component 40a opposite to the end (the end on the mouth 11a side) where the preform 10a is embedded is subjected to heat compression. This heat compression can be performed by heating the compression portion using infrared rays, hot air, or the like, and then sandwiching the end 40b of the plastic component 40a using a pair of compression tools 90A and 90B as shown in FIG18. The pair of compression tools 90A and 90B each have a concave receiving portion 90C that is approximately semi-cylindrical (or approximately hemispherical) and has a shape corresponding to the bottom 30a of the preform 10a. In this case, the pair of compression tools 90A and 90B are brought closer to each other from both sides of the axial direction of the plastic component 40a and moved so that the pair of concave receiving portions 90C enclose the bottom 30a of the preform 10a. As a result, the opening 48d formed in the cylindrical end portion 40b of the plastic member 40a is sealed, and the first piece 47a and the second piece 47b are thermocompressed to form the compression bottom portion 45. The material of the compression tools 90A and 90B is not particularly limited, and metal or heat-resistant resin compression tools can be used.

By using the crimping tools 90A and 90B shown in Figure 18, the end 40b of the plastic component 40a can be hot-compressed along the bottom 30a of the preform 10a. It should be noted that the shape of the crimping tools 90A and 90B is not particularly limited, as long as the plastic component 40a can be hot-compressed along the bottom 30a of the preform 10a. The surface of the concave receiving portion 90C of the crimping tools 90A and 90B can be flat, or it can have a concave-convex shape in part or in whole. In addition, the crimping tools 90A and 90B can have a heating mechanism on their surface. This can further improve the crimping strength. The heating temperature of the crimping tool surface is preferably above 100°C and below 250°C, for example.

The pressure during compression bonding 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 during pressure bonding varies depending on the material, but is preferably 80°C or higher and 200°C or lower.

Furthermore, the end portion 40b of the plastic component 40a after thermal compression bonding can be cut to an appropriate length as desired. This ensures a favorable appearance of the bottom portion 30 of the finished composite container 10A. Specifically, it is preferable to cut the bottom portion 30a of the preform 10a so that the length Z (see FIG. 1 ) from the apex of the bottom portion 30a to the end of the plastic component 40a after compression bonding is between 0.5 mm and 5 mm. The compression bonded bottom portion 45 can be cut in a straight line as shown in FIG. 2 , or it can be cut in a curved line that follows the shape of the bottom portion of the preform 10a (not shown).

The heat-shrinkable plastic member 40a after heat shrinkage is not bonded to the outer surface of the preform 10a, and is in close contact with the preform 10a to such an extent that it does not move or rotate, or does not fall due to its own weight.

Composite container 10A

The structure of the composite container 10A produced using the composite preform 70 of this embodiment is substantially the same as that of the first embodiment.

It should be noted that in this embodiment, the heat-shrinkable plastic component 40 is also tightly attached to the outer surface of the container body 10 in a thinly extended state and is installed in a state that is not easily moved or rotated relative to the container body 10. In addition, one end of the heat-shrinkable plastic component 40 on the side of the bottom 30 of the container body 10 is crimped to form a crimped bottom 45A (see Figure 3). In this case, the heat-shrinkable plastic component 40 is crimped at a position covering the bottom 30 of the container body 10. Specifically, the first piece 47a and the second piece 47b (Figure 15) of the heat-shrinkable plastic component 40a of the composite preform 70 described above are heat-compression-bonded in such a manner that they overlap. As a result, the opening 48d (Figure 18) of the heat-shrinkable plastic component 40a is closed after blow molding, and the bottom 30 is completely covered by the heat-shrinkable plastic component 40.

Method for manufacturing composite container

The method for manufacturing the composite container 10A of this embodiment is substantially the same as that of the first embodiment. Specifically, the method for manufacturing the composite container 10A of this embodiment includes the steps of heating the composite preform 70 and inserting it into a blow molding die; and blow molding the heated composite preform 70 to integrate the preform 10a and the heat-shrinkable plastic member 40a and expand the preform.

[Example]

Hereinafter, the present embodiment will be described in further detail using examples, but the present embodiment is not limited to these examples.

(Step of Preparing Preform 10a)

An injection molding machine was used to produce a preform 10a made of PET as shown in Fig. 8. The preform 10a weighed 23.8 g, and the sum of the lengths Y of the main body 20a and the bottom 30a was 90 mm.

(Step of Preparing the Heat-Shrinkable Plastic Member 40a)

A polyolefin resin is melted and extruded from a ring-shaped die. The inner surface of the extruded tube is then pressurized, or the outer surface of the tube is expanded to a negative pressure relative to the inner surface, thereby producing a heat-shrinkable plastic component 40a. The length X of the produced heat-shrinkable plastic component 40a is 100 mm.

(Embedding process)

Next, the preform 10a is manually inserted from one end of the heat-shrinkable plastic member 40a.

(Heat shrinkage and thermocompression bonding process)

After embedding, the preform 10a and the heat-shrinkable plastic member 40a were heated to 100°C using an infrared heater, causing the heat-shrinkable plastic member 40a to shrink. Next, using a pair of crimping tools 90A and 90B (shown in FIG. 18 ), heated to 100°C, one end of the plastic member 40a was sandwiched with a pressure of 300 N/ ^cm² . This allowed the preform 10a to be thermocompressed along the shape of the bottom portion 30a, yielding a composite preform 70.

(Manufacturing of Composite Container 10A)

The composite preform 70 obtained above was heated to 100°C using an infrared heater and transferred to a blow molding die. The composite preform 70 was blow-molded in the blow molding die to produce a composite container 10A with a full fill capacity of 500 mL. The plastic member 40 included in the composite container 10A covered the bottom of the container body 10, and no peeling or damage was observed at the press-bonded portion, nor were any bubbles confirmed.

(Fourth embodiment)

Next, a fourth embodiment of the present invention will be described. Figures 19 and 20 illustrate the fourth embodiment of the present invention. The fourth embodiment shown in Figures 19 and 20 differs in that a twisting portion 80 is formed at the end of the plastic member 40a. The remaining configuration is essentially the same as the first embodiment described above. In Figures 19 and 20, components identical to those of the first embodiment shown in Figures 1 to 10 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

Composite preform 70

Fig. 19 shows a composite preform 70 according to this embodiment. As shown in Fig. 19, the composite preform 70 according to this embodiment includes a preform 10a made of a plastic material and a substantially bottomed cylindrical heat-shrinkable plastic member 40a provided to surround the outside of the preform 10a.

The preform 10a includes a mouth 11a, a body 20a connected to the mouth 11a, and a bottom 30a connected to the body 20a. The configuration of the preform 10a is the same as that of the first embodiment, and therefore detailed description thereof will be omitted.

In this case, the heat-shrinkable plastic member 40a is longer than the main body 20a and bottom 30a of the preform 10a. Furthermore, a blank portion 80a for thermocompression bonding is formed at the end (one end) 40b of the plastic member 40a on the bottom 30a side of the preform 10a. This blank portion 80a is thermocompressed and twisted to form a twisted portion 80.

In the present embodiment, a composite container 10A can be obtained by blow molding a composite preform 70 shown in FIG. 19 .

Composite container 10A

The structure of the composite container 10A produced using the composite preform 70 of this embodiment is substantially the same as that of the first embodiment.

It should be noted that, in the present embodiment, the heat-shrinkable plastic component 40 is also tightly fitted in a state of thinly extending on the outer surface of the container body 10, and is installed in a state that is not easily moved or rotated relative to the container body 10. In addition, in the heat-shrinkable plastic component 40, one end on the side of the bottom 30 of the container body 10 is crimped to form a crimped bottom 45A (see FIG3 ). In this case, the heat-shrinkable plastic component 40 is crimped at a position covering the bottom 30 of the container body 10. Specifically, the heat-shrinkable plastic component 40 is crimped in such a manner that the twisted portion 80 (see FIG19 ) of the composite preform 70 is flattened. As a result, the opening 48d (see FIG6 ) of the heat-shrinkable plastic component 40a is closed after blow molding, and the bottom 30 is completely covered by the heat-shrinkable plastic component 40.

Method for manufacturing composite preform 70

Next, a method for manufacturing the composite preform 70 according to the present embodiment will be described.

The manufacturing method of the composite preform 70 of this embodiment includes: a process of preparing a preform 10a, which has a mouth 11a, a main body 20a connected to the mouth 11a, and a bottom 30a connected to the main body 20a; a process of preparing a tubular heat-shrinkable plastic component 40a, which has a blank portion 80a for heat pressing at one end; a process of embedding the preform 10a from the other end of the plastic component 40a; a process of heating the plastic component 40a to cause the plastic component 40a to shrink thermally; a process of heat pressing the blank portion 80a of the plastic component 40a; and a process of twisting the blank portion 80a after heat pressing to form a twisted portion 80.

Hereinafter, each step will be described in detail.

Process of preparing preforms and heat-shrinkable plastic parts

First, the preform 10a and the heat-shrinkable plastic member 40a are prepared in the same manner as in the first embodiment.

The heat-shrinkable plastic member 40a is longer than the combined length of the main body 20a and bottom 30a of the preform 10a and has a margin 80a at its end (one end 40b) (see FIG6 ). The margin 80a is preferably 3 mm or longer, more preferably 5 mm or longer and 20 mm or shorter. By setting the margin 80a length within this numerical range, the thermocompression bonding process and the twisting process of the margin 80a can be performed more easily, and the material used can be reduced, thereby reducing costs.

Embedding process

Next, a heat-shrinkable plastic member 40a, which is open at both ends, is fitted into the preform 10a from one end. The heat-shrinkable plastic member 40a covers the periphery of the main body 20a and bottom 30a of the preform 10a, excluding the opening 11a. In this case, the preform 10a is fitted from the side of the heat-shrinkable plastic member 40a opposite to the side where the margin 80a is provided.

Heat shrink process

Next, the preform 10a and the heat-shrinkable plastic member 40a are heated, whereby the heat-shrinkable plastic member 40a shrinks and adheres closely to the outer surface of the preform 10a. After heat shrinkage, the heat-shrinkable plastic member 40a is not bonded to the outer surface of the preform 10a, but adheres closely to the preform 10a to such an extent that it does not move or rotate relative to the preform 10a, or to such an extent that it does not fall due to its own weight.

Thermal compression bonding process

Next, the end (other end) 40b of the plastic member 40a opposite to the end (end on the mouth 11a side) where the preform 10a was inserted is thermocompressed. The method for thermocompressing the blank portion 80a is not particularly limited, and can be performed in the same manner as in the first embodiment, for example.

Twisted portion 80 forming step

Next, the thermally compressed margin 80a is twisted to form the twisted portion 80 shown in FIG19 . This prevents the formation of bubbles between the container body 10 and the plastic component 40 of the blow-molded composite container 10A, and prevents the thermally compressed margin 80a from being damaged, such as by peeling off, during blow molding. Furthermore, by twisting the margin 80a and blow-molding the plastic component 40a forming the twisted portion 80, a plastic component 40 having a bottom with a good appearance can be obtained.

The method for forming the twisted portion 80 is not particularly limited. The twisted portion 80 can be formed manually by twisting the margin portion 80a using a bench or other tool. Alternatively, the twisted portion 80a can be formed mechanically using a rotating device (see FIG. 20 ) comprising a holding portion 81 for holding the preform 10a and the plastic component 40a, and crimping tools 82 and 83 having a rotating mechanism. Alternatively, a combination of these methods can be used. Specifically, the twisted portion 80 can be formed by clamping the margin portion 80a using a bench or other tool and rotating the preform 10a and the plastic component 40a using a rotating device.

In one embodiment, the formation of the twisting portion 80 can be performed simultaneously with the hot pressing of the blank portion 80a. As a result, the number of working steps can be reduced and productivity can be further improved. Specifically, the preform 10a and the plastic component 40a can be fixed to the holding portion 81 by providing a rotating mechanism on the crimping tools 82 and 83, and the crimping tools 82 and 83 can be rotated. In addition, the preform 10a and the plastic component 40a can be rotated by using the rotating portion by using the crimping tools 82 and 83 as holding portions. There is no particular limitation on the degree of twisting of the blank portion 80a, and it can be between 0.25 turns and 30 turns, or it can be twisted off. It is preferably twisted off because it can make the appearance better and can effectively prevent the hot pressed portion from being damaged by blow molding.

Method for manufacturing composite container 10A

The method for manufacturing the composite container 10A of this embodiment is substantially the same as that of the first embodiment. Specifically, the method for manufacturing the composite container 10A of this embodiment includes: a step of heating the composite preform 70 manufactured as described above and inserting it into a blow molding die; and a step of blow molding the heated composite preform 70 to integrate the preform 10a and the heat-shrinkable plastic member 40a and expand the preform.

[Example]

Hereinafter, the present invention will be described in further detail using examples, but the present invention is not limited to these examples.

(Step of Preparing Preform 10a)

An injection molding machine was used to produce a preform 10a made of PET as shown in Fig. 8. The preform 10a weighed 23.8 g, and the length Y between the main body 20a and the bottom 30a was 90 mm.

(Step of Preparing the Heat-Shrinkable Plastic Member 40a)

A polyolefin resin is melted and extruded from a ring-shaped die. The inner surface of the extruded tube is then pressurized, or the outer surface of the tube is expanded to a negative pressure relative to the inner surface, thereby producing a heat-shrinkable plastic component 40a. The length X of the heat-shrinkable plastic component 40a produced is 100 mm, and the length of the blank portion 80a is 10 mm.

(Embedding process)

Next, the preform 10a is manually inserted from the end of the heat-shrinkable plastic member 40a opposite to the blank portion 80a.

(Heat Shrinkage and Thermocompression Bonding Step, Twisted Portion 80 Forming Step)

After embedding, the preform 10a and the heat-shrinkable plastic member 40a are heated to 100°C using an infrared heater to heat-shrink the heat-shrinkable plastic member 40a.

Next, the preform 10a and the plastic component 40a are fixed to a holding portion 81 shown in FIG20 . Using crimping tools 82 and 83 heated to 100°C and equipped with a rotating mechanism, shown in FIG20 , the blank portion 80a is sandwiched therebetween at a pressure of 300 N/ ^cm² and thermocompression-bonded. Furthermore, the preform 10a and the plastic component 40a are rotated by the rotating mechanism until the crimped blank portion 80a is twisted off, thereby forming a twisted portion 80 (see FIG19 ).

(Manufacturing of composite containers)

The composite preform 70 obtained above was heated to 100°C using an infrared heater and transferred to a blow molding die. The composite preform 70 was blow-molded in the blow molding die to produce a composite container 10A with a full fill capacity of 500 mL. In this composite container 10A, the container body 10 was covered to the bottom with the plastic member 40. No bubbles were observed between the container body 10 and the plastic member 40.

(Fifth embodiment)

Next, the fifth embodiment of the present invention will be described. Figures 21 to 25 illustrate the fifth embodiment of the present invention. The fifth embodiment shown in Figures 21 to 25 differs primarily in that a first notch 49a and a second notch 49b are formed in the plastic member 40a. The remaining configuration is essentially the same as the first embodiment described above. In Figures 21 to 25, components identical to those of the first embodiment shown in Figures 1 to 10 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

Composition of composite containers

The structure of the composite container 10A of this embodiment is substantially the same as that of the first embodiment (Figures 3 and 4). It should be noted that in this embodiment, the heat-shrinkable plastic member 40 is crimped at a position covering the bottom 30 of the container body 10, forming a crimped bottom 45A. Specifically, the heat-shrinkable plastic member 40a is heat-compressed so that the first piece 47a and the second piece 47b (Figure 22) of the heat-shrinkable plastic member 40a of the composite preform 70, described later, overlap. As a result, the opening 48d (Figures 21 and 22) of the heat-shrinkable plastic member 40a is sealed after blow molding, and the bottom 30 is completely covered by the heat-shrinkable plastic member 40.

Composition of composite preform

Next, the structure of the composite preform of this embodiment will be described using FIG. 21 .

As shown in FIG. 21 , the composite preform 70 includes a preform 10 a made of a plastic material and a substantially cylindrical heat-shrinkable plastic member 40 a provided so as to surround the outside of the preform 10 a .

The preform 10a includes a mouth 11a, a body 20a connected to the mouth 11a, and a bottom 30a connected to the body 20a. The configuration of the preform 10a is the same as that of the first embodiment, so detailed description is omitted here.

The heat-shrinkable plastic member 40a is attached to the outer surface of the preform 10a without being bonded thereto. It is in close contact with the preform 10a to prevent movement or rotation, or to prevent it from falling due to its own weight. The heat-shrinkable plastic member 40a is provided around the entire circumference of the preform 10a and has a circular horizontal cross-section.

In this case, the heat-shrinkable plastic member 40a is provided so as to cover the entire region except for the mouth portion 11a and the lower surface 30b of the bottom portion 30a.

The heat-shrinkable plastic member 40a includes a wide diameter portion 48a and a narrow diameter portion 48b having a smaller diameter than the wide diameter portion 48a. A transition portion 48c is interposed between the wide diameter portion 48a and the narrow diameter portion 48b.

The wide diameter portion 48a is substantially cylindrical and covers the entire body portion 20a of the preform 10a. However, the wide diameter portion 48a is not limited thereto and may cover a portion of the body portion 20a, for example, the area excluding the area 13a corresponding to the neck portion 13.

The narrow diameter portion 48b is generally cylindrical and extends outward (opposite to the mouth 11a) from the bottom 30a of the preform 10a. An opening 48d is formed in the area surrounded by the narrow diameter portion 48b. The lower surface 30b of the bottom 30a is exposed to the outside through the opening 48d. In addition, the narrow diameter portion 48b is formed by causing the heat-shrinkable plastic component 40a to shrink to a smaller diameter than the wide diameter portion 48a. It should be noted that the length L1 of the narrow diameter portion 48b can be, for example, not less than 30% and not more than 100% of the diameter D1 of the wide diameter portion 48a. In addition, the diameter D2 of the narrow diameter portion 48b can be, for example, not less than 30% and not more than 90% of the diameter D1 of the wide diameter portion 48a.

The transition portion 48c connects the wide portion 48a and the narrow portion 48b. This transition portion 48c is formed along the bottom portion 30a of the preform 10a. Specifically, the transition portion 48c corresponds to the shape of the bottom portion 30a, in this case forming a portion of a spherical surface. Furthermore, the horizontal cross-section of the transition portion 48c is approximately circular, with its diameter gradually decreasing from the wide portion 48a toward the narrow portion 48b.

FIG22 is a perspective view of the portion surrounding the bottom portion 30a of the heat-shrinkable plastic component 40a. As shown in FIG22, a first cutout portion 49a and a second cutout portion 49b are formed in the narrow portion 48b. The first cutout portion 49a and the second cutout portion 49b are arranged at positions opposite to each other in the radial direction of the narrow portion 48b. The first cutout portion 49a and the second cutout portion 49b are formed in a straight line or a V-shape along the wall surface of the narrow portion 48b in the longitudinal direction of the preform 10a. It should be noted that the length L2 of the first cutout portion 49a and the second cutout portion 49b (the length along the longitudinal direction of the preform 10a) is, for example, not less than 3 mm and not more than 20 mm, and is a length that does not reach the bottom portion 30a of the preform 10a.

The narrow portion 48b is formed with a first piece 47a and a second piece 47b separated from each other by a first notch 49a and a second notch 49b. The first piece 47a and the second piece 47b are approximately semicircular arcs when viewed from the bottom surface and face each other with the opening 48d interposed therebetween.

By forming the first and second cutouts 49a, 49b at mutually opposing positions in the narrow-diameter portion 48b, the composite preform 70 can be blow-molded, with the first and second pieces 47a, 47b collapsing toward each other. This eliminates any gap between the heat-shrinkable plastic component 40a and the bottom 30a of the preform 10a, ensuring that the bottom 30 of the container body 10 and the heat-shrinkable plastic component 40 are substantially evenly covered after blow molding. Consequently, the appearance, light-shielding properties, and gas-barrier properties of the heat-shrinkable plastic component 40 of the bottom 30 of the container body 10 are not likely to deteriorate. Furthermore, the problem of a gap between the bottom 30 of the container body 10 and the heat-shrinkable plastic component 40 due to trapped air can be prevented, preventing degradation of the appearance.

Composition of heat-shrinkable plastic parts

FIG. 23 is a perspective view showing the heat-shrinkable plastic member 40 a before heat shrinkage (before attachment to the preform 10 a ).

As shown in FIG23 , the heat-shrinkable plastic member 40a is generally cylindrical and includes a main body 41 and one end 41a and the other end 41b formed at both ends in the longitudinal direction of the main body 41. The one end 41a of the main body 41 faces the mouth 11a when the heat-shrinkable plastic member 40a is attached to the preform 10a, while the other end 41b of the main body 41 faces the bottom 30a.

In this case, a first cutout 49a and a second cutout 49b are formed at mutually opposing positions at one end 41a of the heat-shrinkable plastic member 40a. The first cutout 49a and the second cutout 49b are each formed linearly along the longitudinal direction of the main body 41 and terminate midway along the longitudinal direction of the main body 41, respectively, from the one end 41a of the main body 41. Furthermore, a first piece 47a and a second piece 47b (before heat shrinkage) are formed at the one end 41a of the heat-shrinkable plastic member 40a, separated from each other by the first cutout 49a and the second cutout 49b. The length L3 of the first cutout 49a and the second cutout 49b before heat shrinkage is, for example, not less than 5 mm and not more than 20 mm.

As such a heat-shrinkable plastic member 40a, a member having the function of thermally shrinking the preform 10a is used. That is, the heat-shrinkable plastic member (outer shrinkage member) 40a is a member that shrinks relative to the preform 10a when heat is applied.

Method for manufacturing composite preform

Next, a method for manufacturing the composite preform 70 according to the present embodiment will be described using FIG. 24( a ) to FIG. 24 ( c ).

First, a preform 10a made of a plastic material is prepared (see FIG. 24( a )). In this case, the preform 10a is produced by injection molding, for example, using an injection molding machine (not shown). The preform 10a has a mouth 11a, a cylindrical body 20a, and a substantially hemispherical bottom 30a.

Next, a substantially cylindrical heat-shrinkable plastic member 40a ( FIG. 23 ) having one end 41a and the other end 41b is prepared. A first notch 49a and a second notch 49b are formed at mutually opposing positions of the one end 41a of the heat-shrinkable plastic member 40a.

Next, a heat-shrinkable plastic member (outer shrink member) 40a is positioned (slowly inserted) outside the preform 10a (see FIG. 24( b )). In this case, the heat-shrinkable plastic member 40a is slowly inserted into the preform 10a from the other end 41b. The heat-shrinkable plastic member 40a is installed so that, after being slowly inserted into the preform 10a, it covers the entire body 20a and the entire bottom 30a of the preform 10a when viewed from the side. Furthermore, one end 41a of the heat-shrinkable plastic member 40a extends outside the bottom 30a of the preform 10a (on the side opposite the mouth 11a).

Next, the preform 10a and the heat-shrinkable plastic member 40a are heated by the heating device 55 (see FIG. 24( c )). The preform 10a and the heat-shrinkable plastic member 40a are rotated with the mouth 11a facing downward while being uniformly heated in the circumferential direction by the heating device 55. The heating temperature of the preform 10a and the heat-shrinkable plastic member 40a during this heating step can be, for example, 90°C to 130°C.

By heating the heat-shrinkable plastic member 40a in this manner, it shrinks and adheres tightly to the outside of the preform 10a (see FIG24(c)). At this point, the heat-shrinkable plastic member 40a adheres tightly to the preform 10a along the main body 20a and the bottom 30a, forming a wide diameter portion 48a and a transition portion 48c. Meanwhile, the portion of the heat-shrinkable plastic member 40a that extends outside the bottom 30a of the preform 10a shrinks radially inward to form a narrow diameter portion 48b. At this point, the narrow diameter portion 48b forms a first piece 47a and a second piece 47b, separated from each other by a first notch 49a and a second notch 49b (see FIG22).

By providing the heat-shrinkable plastic member 40a outside the preform 10a in this manner, a composite preform 70 including the preform 10a and the heat-shrinkable plastic member 40a in close contact with the outside of the preform 10a can be obtained (see FIG. 24(c) ).

By pre-sealing the heat-shrinkable plastic component 40a to the outer side of the preform 10a in this manner to produce the composite preform 70, a series of steps for producing the composite preform 70 (Figures 24(a) to (c)) and a series of steps for producing the composite container 10A by blow molding described later (Figures 24(d) to (g)) can be carried out in separate locations (factories, etc.).

It should be noted that the above description uses the example of attaching the heat-shrinkable plastic member 40a, which has the first cutout portion 49a and the second cutout portion 49b formed in advance, to the preform 10a. However, the present invention is not limited to this, and the first cutout portion 49a and the second cutout portion 49b may be formed after the heat-shrinkable plastic member 40a is attached to the preform 10a.

In this case, first, prepare the preform 10a in the same manner as in the above-described case. Next, prepare a heat-shrinkable plastic member 40a without the first cutout 49a and the second cutout 49b. Then, slowly insert the heat-shrinkable plastic member 40a into the preform 10a, and then heat-shrink the heat-shrinkable plastic member 40a, thereby causing it to adhere tightly to the outside of the preform 10a. Then, form the first cutout 49a and the second cutout 49b at opposing positions at one end 41a of the open side of the heat-shrinkable plastic member 40a. This produces a composite preform 70 (see FIG. 21 ).

Method for manufacturing composite container

Next, a method for manufacturing the composite container 10A according to the present embodiment (blow molding method) will be described using FIG. 24( d ) to FIG. 24 ( g ).

For example, a composite preform 70 is produced through the above-described steps (see Figures 24(a) to (c)). Next, the composite preform 70 is heated by the heating device 51 (see Figure 24(d)). At this time, the composite preform 70 is uniformly heated circumferentially by the heating device 51 while rotating with the mouth 11a facing downward. The heating temperature of the preform 10a and the heat-shrinkable plastic member 40a during this heating step is, for example, 90°C to 130°C.

Next, the composite preform 70 heated by the heating device 51 is sent to the blow molding die 50 (see FIG. 24( e )).

The composite container 10A is molded using this blow molding die 50. In this case, the blow molding die 50 consists of a pair of separate main body molds 50a and 50b and a bottom mold 50c (see FIG24(e)). In FIG24(e), the pair of main body molds 50a and 50b are open to each other, and the bottom mold 50c is raised. In this state, the composite preform 70 is inserted between the pair of main body molds 50a and 50b.

Next, as shown in FIG24(f), after the bottom mold 50c is lowered, the pair of main body molds 50a and 50b are closed, and the pair of main body molds 50a and 50b and the bottom mold 50c form a closed blow molding mold 50. Next, air is pressed into the preform 10a to perform biaxial stretch blow molding on the composite preform 70.

Thus, the container body 10 is obtained from the preform 10a within the blow mold 50. During this time, the main body molds 50a and 50b are heated to 30°C to 80°C, and the bottom mold 50c is cooled to 5°C to 25°C. At this time, the preform 10a and the heat-shrinkable plastic member 40a of the composite preform 70 are integrated and expanded within the blow mold 50. As a result, the preform 10a and the heat-shrinkable plastic member 40a are integrated and shaped to conform to the inner surface of the blow mold 50.

In this manner, a composite container 10A is obtained, comprising a container body 10 and a heat-shrinkable plastic member 40 disposed on the outer surface of the container body 10. At this time, the first and second pieces 47a, 47b ( FIG. 22 ) formed on the narrow portion 48b of the heat-shrinkable plastic member 40a are collapsed toward each other. As a result, the heat-shrinkable plastic member 40a is press-bonded at a position covering the bottom 30 of the container body 10. At this point, no gap is formed between the heat-shrinkable plastic member 40a and the bottom 30a of the preform 10a. Therefore, the bottom 30 of the container body 10 is substantially evenly covered by the heat-shrinkable plastic member 40, and the appearance of the heat-shrinkable plastic member 40 at the bottom 30 is not likely to deteriorate. Furthermore, air is less likely to remain trapped between the bottom 30 of the container body 10 and the heat-shrinkable plastic member 40, thereby preventing the formation of a gap between the heat-shrinkable plastic member 40 and the bottom 30.

Next, as shown in FIG. 24( g ), the pair of main body molds 50 a and 50 b and the bottom mold 50 c are separated from each other, and the composite container 10A is removed from the blow molding mold 50 .

Thus, according to this embodiment, the first and second notches 49a, 49b are formed at mutually opposing positions in the narrow portion 48b of the heat-shrinkable plastic member 40a. Consequently, during blow molding of the composite preform 70, the narrow portion 48b deforms, narrowing the first and second pieces 47a, 47b. This allows the bottom 30 of the container body 10 to fit evenly and closely to the heat-shrinkable plastic member 40 after blow molding, improving the appearance, light-shielding properties, and gas-barrier properties of the bottom 30. Furthermore, air can be prevented from entrapped between the bottom 30 of the container body 10 and the heat-shrinkable plastic member 40, preventing deterioration in appearance. As a result, a high-quality composite container 10A can be manufactured, endowed with various functions and characteristics, such as light-shielding properties and gas-barrier properties.

Furthermore, according to this embodiment, a conventional blow molding apparatus can be used directly to produce the composite container 10A, eliminating the need for new molding equipment for producing the composite container 10A. Furthermore, since the heat-shrinkable plastic member 40a is provided outside the preform 10a, new molding equipment for molding the preform 10a is also unnecessary.

Modification

Next, a modified example of the composite preform 70 of this embodiment will be described using FIG. The modified example shown in FIG. 25 differs in that a portion of the first sheet 47a and a portion of the second sheet 47b are press-bonded to each other. The remaining configuration is substantially the same as the embodiment shown in FIG. 21 to FIG. 24 . In FIG. 25 , the same reference numerals are assigned to the same parts as in FIG. 21 to FIG. 24 , and detailed descriptions thereof will be omitted.

As shown in FIG. 25 , in the composite preform 70 , a first piece 47 a and a second piece 47 b separated from each other by a first notch 49 a and a second notch 49 b are formed in the narrow diameter portion 48 b .

In this case, a portion of the first piece 47a and a portion of the second piece 47b are press-bonded to each other. Specifically, a first press-bonded portion 47c located approximately midway between the first cutout 49a and the second cutout 49b of the first piece 47a and a second press-bonded portion 47d located approximately midway between the first cutout 49a and the second cutout 49b of the second piece 47b are heat-bonded to each other. Thus, the first press-bonded portion 47c and the second press-bonded portion 47d are connected to each other, integrating the first piece 47a and the second piece 47b. Furthermore, the first piece 47a and the second piece 47b are formed into a W-shape or an ω-shape, respectively, when viewed from the bottom.

When manufacturing such a composite preform 70, a step of press-bonding a portion of the first sheet 47a and a portion of the second sheet 47b is performed after the step of heat-shrinking the heat-shrinkable plastic member 40a ( FIG. 24( c )) and before the step of heating the composite preform 70 using the heating device 51 ( FIG. 24( d )). Specifically, while the heat-shrinkable plastic member 40a is at a high temperature immediately after the heat-shrinking step ( FIG. 24( c )), a heat-bonding tool (not shown) is used to sandwich the first press-bonded portion 47c of the first sheet 47a and the second press-bonded portion 47d of the second sheet 47b with the first press-bonded portion 47c facing inward, thereby press-bonding the first press-bonded portion 47c and the second press-bonded portion 47d (see the arrows in FIG. 25 ). Alternatively, after the heat-shrinkable plastic member 40a cools, the heat-bonded portion 47c and the second press-bonded portion 47d may be melt-bonded using a heated tool (not shown). Alternatively, after the heat-shrinkable plastic member 40a has cooled, a tool (not shown) or the like may be ultrasonically vibrated to perform melt-compression bonding utilizing the heat generated by the vibration. It should be noted that the conditions (temperature, pressure, etc.) during this compression bonding may be the same as those in the first embodiment.

In this manner, when using the composite preform 70 shown in FIG. 25 , during blow molding of the composite preform 70, the narrowed portion 48b deforms, narrowing the first and second sheets 47a, 47b. Consequently, after blow molding, the bottom 30 of the container body 10 and the heat-shrinkable plastic member 40 are evenly and tightly fitted, resulting in a good appearance of the bottom 30. Furthermore, during the blow molding process, air is simultaneously exhausted from the openings 48d, effectively preventing air from remaining between the bottom 30 of the container body 10 and the heat-shrinkable plastic member 40. Furthermore, by press-bonding a portion of the first sheet 47a and a portion of the second sheet 47b, the tight fit between the bottom 30 of the container body 10 and the heat-shrinkable plastic member 40 is further ensured, enabling the manufacture of a high-quality composite container 10A having a good appearance and excellent light-shielding properties.

Claims (20)

1. A method for manufacturing a composite preform, characterized in that, The manufacturing method comprises: A process for preparing a preform made of plastic material, the preform having an opening, a main body connected to the opening, and a bottom connected to the main body; The process of preparing a tubular heat-shrinkable plastic component, wherein the heat-shrinkable plastic component has a blank portion at one end for heat pressing and is longer than the length of the main body and the bottom of the preform; The process of embedding the preform into the plastic component; The process of causing the plastic component to shrink thermally by heating the preform and the plastic component; and The process of heat-pressing the blank portion of the plastic component after it has undergone heat shrinkage is described. In the blank area, a first opposing surface and a second opposing surface are formed and arranged opposite to each other, and a portion of the first opposing surface and a portion of the second opposing surface are pressed together. The end edges of the first opposing surface and the end edges of the second opposing surface are pressed together in a staggered manner along the axial direction of the plastic component. 2. The method for manufacturing a composite preform as described in claim 1, wherein the length of the blank portion is 3 mm or more. 3. The method for manufacturing a composite preform as described in claim 1, wherein the hot pressing of the blank portion is performed using a tool with a flat surface or an uneven shape. 4. The method for manufacturing the composite preform as described in claim 3, wherein the surface temperature of the appliance is above 100°C and below 250°C. 5. The method for manufacturing a composite preform as described in claim 1, wherein the pressure during hot pressing of the blank portion is 50 N/ ^cm² or more and 1000 N/ ^cm² or less. 6. The method for manufacturing a composite preform as described in claim 1, wherein the temperature of the heat-shrinkable plastic component during the hot pressing of the blank portion is above 80°C and below 200°C. 7. A method for manufacturing a composite container, characterized in that, The manufacturing method comprises: The process of heating the composite preform obtained by the method of claim 1 and inserting it into a blow molding die; and The process of blowing the heated composite preform into a single unit, which expands the preform and the plastic component. 8. A composite preform, characterized in that, The composite preform comprises: A preform having an opening, a main body connected to the opening, and a bottom connected to the main body; and A heat-shrinkable plastic component is provided to surround the outer side of the preform, has a blank portion at one end for heat pressing, and is longer than the main body and bottom of the preform. The blank portion of the plastic component was heat-pressed along the shape of the bottom of the preform. In the blank area, a first opposing surface and a second opposing surface are formed and arranged opposite to each other, and a portion of the first opposing surface and a portion of the second opposing surface are pressed together. The end edges of the first opposing surface and the end edges of the second opposing surface are pressed together in a staggered manner along the axial direction of the plastic component. 9. A composite container, which is a blow-molded article of the composite preform as described in claim 8, characterized in that, The composite container comprises: A container body, the container body having an opening, a main body portion disposed below the opening, and a bottom portion disposed below the main body portion; and A heat-shrinkable plastic component is provided to fit tightly against the outer side of the container body. The blank portion of the plastic component was heat-pressed. 10. A method for manufacturing a composite preform, characterized in that, The manufacturing method of the composite preform includes: A process for preparing a preform made of plastic material, the preform having an opening, a main body, and a bottom; The process of preparing heat-shrinkable plastic parts, wherein the heat-shrinkable plastic parts are cylindrical heat-shrinkable plastic parts having one end and another end, and a first cut and a second cut are formed at opposite positions at the one end respectively. The process of slowly inserting the heat-shrinkable plastic component relative to the preform from the other end; and The process of causing the heat-shrinkable plastic component to shrink and thus seal it tightly against the outer side of the preform. The heat-shrinkable plastic component has a wide diameter portion and a narrow diameter portion with a smaller diameter than the wide diameter portion. The first cut and the second cut are formed in the narrow diameter portion. The narrow diameter portion extends outward from the bottom of the preform, and an opening is formed in the area enclosed by the narrow diameter portion. 11. A method for manufacturing a composite preform, characterized in that, The manufacturing method of the composite preform includes: A process for preparing a preform made of plastic material, the preform having an opening, a main body, and a bottom; The process of preparing heat-shrinkable plastic parts; The process of slowly inserting the heat-shrinkable plastic component relative to the preform; The process of causing the heat-shrinkable plastic component to shrink and thus seal it tightly against the outer side of the preform; and The process of forming a first cut and a second cut at opposite positions on one end of the open side of the heat-shrinkable plastic component. The heat-shrinkable plastic component has a wide diameter portion and a narrow diameter portion with a smaller diameter than the wide diameter portion. The first cut and the second cut are formed in the narrow diameter portion. The narrow diameter portion extends outward from the bottom of the preform, and an opening is formed in the area enclosed by the narrow diameter portion. 12. The method for manufacturing the composite preform as described in claim 10, characterized in that, At one end of the heat-shrinkable plastic component, a first piece and a second piece are formed, which are separated from each other by the first cut and the second cut. After the process of heat-shrinking the heat-shrinkable plastic component, a process is provided to press a portion of the first piece and a portion of the second piece together. 13. The method for manufacturing a composite preform as claimed in claim 12, wherein the pressing is performed using a tool with a flat surface or an uneven shape. 14. The method for manufacturing a composite preform as described in claim 13, wherein the surface temperature of the appliance is above 100°C and below 250°C. 15. The method for manufacturing a composite preform as described in claim 12, wherein the pressure during pressing is 50 N/ ^cm² or more and 1000 N/ ^cm² or less. 16. The method for manufacturing a composite preform as described in claim 12, wherein the temperature of the heat-shrinkable plastic component during pressing is above 80°C and below 200°C. 17. A method for manufacturing a composite container, characterized in that, The manufacturing method of composite containers includes: The process of manufacturing a composite preform using the method for manufacturing a composite preform according to claim 12; and The process of blow molding the preform and the heat-shrinkable plastic component of the composite preform into a single unit and expanding them. 18. A composite preform, characterized in that, The composite preform possesses: A preform made of plastic material, the preform having an opening, a body, and a bottom; and A cylindrical heat-shrinkable plastic component, the heat-shrinkable plastic component being arranged to surround the outer side of the preform. The heat-shrinkable plastic component has a cylindrical wide-diameter portion covering at least the main body of the preform, and a narrow-diameter portion extending outward from the bottom of the preform. A first cut and a second cut are formed at mutually opposite positions in the narrow diameter portion. The narrow diameter portion extends outward from the bottom of the preform, and an opening is formed in the area enclosed by the narrow diameter portion. 19. The composite preform as claimed in claim 18, characterized in that a first piece and a second piece are formed in the narrow diameter portion, which are separated from each other by the first cut portion and the second cut portion, and a portion of the first piece and a portion of the second piece are pressed together. 20. A composite container, which is a blow-molded article of the composite preform of claim 18, characterized in that, The composite container comprises: The container body has an opening, a main body, and a bottom; and A heat-shrinkable plastic component is provided to fit tightly against the outer side of the container body. The heat-shrinkable plastic component is press-fitted at the location covering the bottom of the container body.