Heat-shrinkable plastic parts, composite preforms and composite containers

Abstract

The present invention provides heat-shrinkable plastic parts, composite preforms, and composite containers, wherein the composite container is a blow-molded product of the composite preform, and the composite preform comprises a preform and heat-shrinkable plastic parts.

Description

[0001] This application is a divisional application. The original application has the application number 201980044140.X, the application date is July 25, 2019, and the invention title is "Heat-shrinkable plastic parts, composite preforms and composite containers". Technical Field

[0002] The present invention relates to heat-shrinkable plastic parts, composite preforms having the heat-shrinkable plastic parts, and composite containers as blow-molded articles of the composite preforms. Background Technology

[0003] Nowadays, plastic containers are commonly used to hold liquid contents such as food and beverages.

[0004] Such plastic containers for holding liquid contents can be manufactured by inserting a preform into a mold and then biaxially stretching and blow molding it (biaxial stretching and blow molding).

[0005] In addition, in the past, preforms containing single-layer materials, multi-layer materials, or blends of materials such as polyethylene terephthalate (PET) or polypropylene (PP) have been used in the manufacture of plastic containers.

[0006] However, in traditional biaxial blow molding, the preform is typically simply molded into a container shape. Therefore, the means to give the container various functions or properties (barrier properties, insulation, etc.), such as by changing the materials constituting the preform, are limited. In particular, it is difficult to give different functions and properties to different parts of the container (e.g., the main body or the bottom).

[0007] Patent Document 1 discloses a composite container comprising a container body and a heat-shrinkable plastic component, which is obtained by blow molding a composite preform. Alternatively, this composite preform can be manufactured by inserting the preform into the heat-shrinkable plastic component and heating it, but inserting the preform into the heat-shrinkable plastic component requires skilled technique.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2015-128858 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] In this study, the inventors discovered that by including ionomer resin (A) and olefin resin (B) as essential components in heat-shrinkable plastic parts, the ease of insertion of preforms into heat-shrinkable plastic parts can be significantly improved, thereby increasing the production efficiency of composite preforms and composite containers.

[0013] Therefore, the problem to be solved by the present invention is to provide a heat-shrinkable plastic part that can significantly improve the ease of insertion of a preform.

[0014] Furthermore, the problem to be solved by the present invention is to provide a composite preform having the heat-shrinkable plastic component and a composite container as a blow-molded article of the composite preform.

[0015] Methods for solving problems

[0016] The heat-shrinkable plastic component of the present invention is characterized in that it has at least a layer comprising an ionomer resin (A) and an olefin resin (B) as essential components.

[0017] In one embodiment, the storage modulus of the heat-shrinkable plastic component of the present invention is 4.0 × 10⁻⁶ at 25°C. 8 Pa or above.

[0018] The composite preform of the present invention is characterized in that it comprises: a preform having an opening, a main body connected to the opening, and a bottom connected to the main body; and the aforementioned heat-shrinkable plastic component, which is disposed in close contact with the outer side of the preform.

[0019] In one embodiment, the coefficient of dynamic friction between the preform and the heat-shrinkable plastic component in the composite preform of the present invention is 1.1 or less.

[0020] In one embodiment, the static friction coefficient between the preform and the heat-shrinkable plastic component of the present invention is 1.1 or less.

[0021] The composite container of the present invention is characterized in that it is a blow-molded product of the above-mentioned composite preform, which has a container body and a heat-shrinkable plastic component. The container body has a mouth, a neck disposed below the mouth, a shoulder disposed below the neck, a main body disposed below the shoulder, and a bottom disposed below the main body. The heat-shrinkable plastic component is disposed in close contact with the outer side of the container body.

[0022] The effects of the invention

[0023] The heat-shrinkable plastic parts according to the present invention can significantly improve the ease of insertion of preforms and increase the production efficiency of composite preforms and composite containers. Attached Figure Description

[0024] Figure 1 This is a front view showing one embodiment of the heat-shrinkable plastic component 40a of the present invention.

[0025] Figure 2 This is a front view showing another embodiment of the heat-shrinkable plastic component 40a of the present invention.

[0026] Figure 3 This is a schematic cross-sectional view showing one embodiment of the composite preform 70 of the present invention.

[0027] Figure 4 This is a schematic cross-sectional view illustrating another embodiment of the composite preform 70 of the present invention.

[0028] Figure 5 This is a perspective view showing one embodiment of the composite preform 70 of the present invention.

[0029] Figure 6 This is a front view showing another embodiment of the heat-shrinkable plastic component 40a of the present invention.

[0030] Figure 7 This is a front view showing one embodiment of the preform 10a.

[0031] Figure 8 This is a schematic cross-sectional view illustrating one embodiment of the composite container 10A of the present invention.

[0032] Figure 9 This is a schematic cross-sectional view illustrating another embodiment of the composite container 10A of the present invention.

[0033] Figure 10 This is a schematic cross-sectional view illustrating yet another embodiment of the composite container 10A of the present invention.

[0034] Figure 11 This is a schematic diagram illustrating one embodiment of a method for manufacturing the composite container 10A. Detailed Implementation

[0035] The embodiments of the present invention will now be described in detail. However, the present invention is not limited to the embodiments described below, and can be implemented in any way without departing from the essential points of the present invention.

[0036] The heat-shrinkable plastic component of the present invention has at least the property of shrinking upon heating. However, when manufacturing a composite preform by placing the heat-shrinkable plastic component of the present invention on at least a portion of the outer side of a preform, it is not necessarily required to heat-shrink it. Furthermore, components that are no longer heat-shrinkable when forming a composite container are also included in the heat-shrinkable plastic component of the present invention.

[0037] The shape of the heat-shrinkable plastic parts of the present invention is not limited. They are usually film-shaped (sheet-shaped), as described below, but can also be cylindrical films, i.e. tubular.

[0038] <Parts made of heat-shrinkable plastics 40a>

[0039] The heat-shrinkable plastic component 40a of the present invention is characterized in that it comprises at least a layer 41a having an ionomer resin (A) and an olefin resin (B) as essential components. The heat-shrinkable plastic component 40a of the present invention can be as follows: Figure 1 The structure shown is a monolayer composed of layers with ionomer resin (A) and olefin resin (B) as essential components. It can also be as follows: Figure 2 The diagram shows a multilayer structure with additional layers 42a. In the case where the heat-shrinkable plastic component 40a has a multilayer structure, it may have two or more layers 41a with ionomer resin (A) and olefin resin (B) as essential components.

[0040] The following describes an overview of the technical concept of the present invention. However, the present invention is not limited to the scope of the technical concept described below.

[0041] Traditionally, the following method has been used: polyethylene terephthalate (PET) is injection molded to form a preform, which is then blow-molded into a bottle shape, and finally wrapped with a heat-shrinkable film (tube). In this case, polystyrene-based or polyester-based resins are mainly used as the heat-shrinkable film, with polyolefin-based resins being less common. This is because if polyolefin-based resins are used as the heat-shrinkable film, the friction between the heat-shrinkable film and the bottle is low, making it difficult to secure it properly.

[0042] On the other hand, the inventors have discovered that in a method of blow molding both the preform and the heat-shrinkable film (tube) simultaneously after pre-winding the heat-shrinkable film (tube) onto a preform, problems arise when using polystyrene-based or polyester-based resins as the heat-shrinkable film. Specifically, due to excessive contact resistance between the heat-shrinkable film and the preform, it is difficult to wind the heat-shrinkable film onto the preform (in the case of a tube, it is difficult to insert it into the preform). Furthermore, during molding, the preform and polyester resin adhere tightly, making it difficult to break the composite container apart.

[0043] Therefore, it was found that using an olefin resin (B), which is not typically used, in heat-shrinkable films improved the contact resistance with the preform. However, when using only olefin resin (B) to make heat-shrinkable plastic parts, not only was the subsequent blow molding performance insufficient, but the conformability to the bottle body after blow molding was also insufficient. Therefore, it was found that by using a combination of olefin resin (B) and ionomer resin (A), it was possible to maintain the improved contact resistance with the preform while achieving good blow molding performance, and consequently, good conformability to the bottle body after blow molding.

[0044] Ionomer resins undergo ionic dissociation at high temperatures, thus softening under heat during blow molding of the preform and improving its moldability. Conversely, upon cooling, the ionomer resin reforms ionic bonds, thereby enhancing its physical properties and interacting with the polar sites of the polyethylene terephthalate resin forming the bottle body, thus contributing to increased holding power. It should be noted that because this interaction is polar, separation is easily achieved, for example, when the composite container is broken apart.

[0045] In layer 41a, where ionomer resin (A) and olefin resin (B) are essential components, the content of the ionomer resin is preferably 40% by mass or more and 99% by mass or less, more preferably more than 60% by mass and 98.5% by mass or less, further preferably 80% by mass or more and 98% by mass or less, and particularly preferably 85% by mass or more and 97% by mass or less. By keeping the content of the ionomer resin within the above-mentioned range, the recyclability when separating from the container body 10 and removing the heat-shrinkable plastic part 40a can be improved. In addition, when a heat-pressing process is included, it is easier to heat-press one end of the heat-shrinkable plastic part 40a.

[0046] In addition, the content of olefin resin (B) in layer 41a is preferably 1% by mass or more and 60% by mass or less, more preferably 1.5% by mass or more and 40% by mass or less, further preferably 2% by mass or more and 20% by mass or less, and particularly preferably 3% by mass or more and 15% by mass or less.

[0047] In one embodiment, the heat-shrinkable plastic component 40a includes a layer 41a with ionomer resin (A) and olefin resin (B) as essential components.

[0048] By using ionomer resin (A) and olefin resin (B) as necessary components, it is possible to achieve a specific range of storage modulus and coefficient of dynamic friction for heat-shrinkable plastic parts. Furthermore, the ionomer resin (A) and olefin resin (B) have good compatibility, resulting in good transparency and good productivity of heat-shrinkable plastic parts, which is therefore preferred.

[0049] (Ionomer Resin (A))

[0050] There are no particular limitations on the ionomer resin (A), and resins in which ethylene-unsaturated carboxylic acid copolymers, such as ethylene-methacrylic acid copolymers, are cross-linked intermolecularly with metal ions can be used. Furthermore, there are no particular limitations on the metal ions used in the ionomer resin, and sodium, zinc, magnesium, lithium, etc., can be used.

[0051] The melt flow rate of the ionomer resin (A) as measured according to ISO 1133 (temperature 190°C, load 21.17 N) is preferably 0.6 g / 10 min to 1.0 g / 10 min. By keeping the melt flow rate of the ionomer resin (A) within the above range, the productivity of heat-shrinkable plastic parts becomes good.

[0052] The lower limit of the storage modulus (25°C) of the ionomer resin (A) as determined according to JIS K7244-4 is preferably 1.5 × 10⁻⁶. 8 Pa or higher, more preferably 2.0 × 10 Pa 8 Pa or higher, more preferably 2.5 × 10 Pa 8 Pa or above. By keeping the storage modulus (25°C) of the ionomer resin (A) within the above range, the production stability during the molding of heat-shrinkable plastic parts and the insertion properties when the heat-shrinkable plastic parts are covered onto the preform become good.

[0053] (Olefin-based resin (B))

[0054] There is no particular limitation on the olefin-based resin (B), but a polypropylene-based resin is preferred, and materials such as polypropylene homopolymers, polypropylene block copolymers, and polypropylene random copolymers are suitable. In particular, among polypropylene-based resins, from the perspective of compatibility with ionomer resins (A), random copolymers copolymerized with α-olefins having 2 to 10 (excluding 3) carbon atoms are preferred, and random copolymers polymerized using metallocene catalysts are more preferred.

[0055] The melt flow rate (temperature 230°C, load 21.17 N) of the polypropylene resin, as measured according to ISO 1133, is preferably 4 g / 10 min to 9 g / 10 min, more preferably 6 g / 10 min to 8 g / 10 min. By keeping the melt flow rate of the polypropylene resin within the above range, the productivity of heat-shrinkable plastic parts becomes good.

[0056] The storage modulus (25°C) of the polypropylene resin, as determined according to JIS K7244-4, is preferably 7.0 × 10⁻⁶. 8 Pa ~ 2.0 × 10 9 Pa, more preferably 9.0 × 10 8 Pa ~ 1.5 × 109 Pa. By keeping the storage modulus (25°C) of the polypropylene resin within the above range, the insertability of the heat-shrinkable plastic part when it is coated onto the preform becomes good.

[0057] (Other ingredients)

[0058] In addition, layer 41a may also contain thermoplastic resins other than ionomer resin (A) and olefin resin (B). From the perspective of compatibility with ionomer resin (A) and olefin resin (B), olefin resins other than olefin resin (B) are preferred, such as polyethylene resins, cyclic olefin copolymers, ethylene-vinyl acetate copolymers, and other resin materials.

[0059] Layer 41a, which uses ionomer resin (A) and olefin resin (B) as essential components, may also contain two or more of the above-mentioned resin materials as other components. In addition, it may also contain plasticizers, fillers, ultraviolet stabilizers, anti-coloring agents, fluorescent whitening agents, matting agents, deodorizers, flame retardants, weathering agents, antistatic agents, linear friction reducers, slip agents, release agents, antioxidants, ion exchangers, dispersants, ultraviolet absorbers and other additives.

[0060] (Shape of parts made of heat-shrinkable plastic)

[0061] In one embodiment, the shape of the heat-shrinkable plastic component 40a is as follows: Figure 1 and 2 The image shows a bottomless cylindrical shape.

[0062] The inner diameter of the heat-shrinkable plastic component 40a can be optimized according to the shape and size of the preform, preferably 22 mm to 65 mm, more preferably 24 mm to 60 mm. By making the inner diameter of the heat-shrinkable plastic component 40a within the above-mentioned range, the insertion of the preform 10a (described later) can be made easier, and the production efficiency of the composite preform 70 can be improved.

[0063] The thickness of the heat-shrinkable plastic component 40a is preferably 200 μm to 500 μm, more preferably 220 μm to 400 μm, and even more preferably 250 μm to 350 μm. By ensuring the thickness of the heat-shrinkable plastic component 40a is within the above-mentioned range, the insertion of the preform 10a can be made easier. Here, when the heat-shrinkable plastic component 40a is multi-layered, the above-mentioned values ​​refer to the total thickness of all layers.

[0064] Furthermore, when the heat-shrinkable plastic component 40a is configured as a multilayer structure, it is preferable to have a layer containing ionomer resin (A) and olefin resin (B), a gas barrier layer, and another layer containing ionomer resin (A) and olefin resin (B) from the inside out.

[0065] As a gas barrier layer, a layer containing resins with gas barrier properties, such as ethylene-vinyl alcohol copolymers, nylon MXD-6, and cyclic polyolefins, can be used. For ethylene-vinyl alcohol copolymers, EVAL (manufactured by KURARAY Corporation) and Soarnol (manufactured by Mitsubishi Chemical Corporation) can be used.

[0066] Alternatively, the structure may consist of two layers: a layer containing ionomer resin (A) and an olefin resin (B), and a gas barrier layer. Alternatively, it may consist of a layer containing ionomer resin (A) and an olefin resin (B), a gas barrier layer, and other layers. In these configurations, the layer containing ionomer resin (A) and olefin resin (B) is preferably disposed on the side in contact with the preform.

[0067] Furthermore, it is preferable to also provide an adhesive layer between the layer containing the ionomer resin (A) and the olefin resin (B) and the gas barrier layer. As the adhesive layer, for example, Admer (manufactured by Mitsui Chemicals Co., Ltd.) or MODIC (manufactured by Mitsubishi Chemical Co., Ltd.), which are polyolefin adhesive resins, can be used.

[0068] As described above, when the heat-shrinkable plastic component 40a is composed of multiple layers, the thickness of the layers containing ionomer resin (A) and olefin resin (B) is not particularly limited, but from the perspective of conformability to the container after blow molding, it is preferable to be 40 μm to 200 μm respectively.

[0069] In addition, in order to achieve good gas barrier properties, the thickness of the gas barrier layer is preferably 20μm to 60μm, more preferably 25μm to 60μm, and even more preferably 30μm to 60μm.

[0070] (Storage modulus of heat-shrinkable plastic parts)

[0071] The preferred storage modulus of the heat-shrinkable plastic component 40a at 25°C is 4.0 × 10⁻⁶. 8 Pa or above 1.0 × 10 9 Pa or less, more preferably 4.5 × 10 Pa 8 Pa or above 9.0 × 10 8 Pa or less, more preferably 5.0 × 10 Pa 8 Pa or above 8.0 × 10 8Pa or less. By keeping the storage modulus (25°C) of the heat-shrinkable plastic part within the above range, the insertion performance of the preform into the heat-shrinkable plastic part 40a becomes good.

[0072] It should be noted that, in this invention, the storage modulus of the heat-shrinkable plastic component 40a can be determined according to the method of JISK7244-4.

[0073] The storage modulus of the heat-shrinkable plastic component 40a can be adjusted by the type of ionomer resin (A) or olefin resin (B), the optimization of melt flow rate, or the mixing ratio of these resins.

[0074] (Coefficient of kinetic friction of heat-shrinkable plastic parts)

[0075] The coefficient of dynamic friction between the heat-shrinkable plastic component 40a and the preform 10a (described later) needs to be 1.1 or less. More preferably, it is 1.0 or less, and even more preferably 0.6 or less. Furthermore, there is no particular limitation on the lower limit of the coefficient of dynamic friction, but it is preferably 0.3 or more, and more preferably 0.4 or more. By ensuring that the coefficient of dynamic friction between the heat-shrinkable plastic component and the preform is within the above range, the preform can be inserted into the heat-shrinkable plastic component without resistance.

[0076] Regarding the coefficient of kinetic friction between the heat-shrinkable plastic component 40a and the preform 10a, the two surfaces (the inner and outer surfaces in the case of a tubular shape) can be the same or different, as long as at least one surface meets the above conditions. In the case that the heat-shrinkable plastic component 40a is tubular, it is preferable that at least the inner surface meets the above conditions.

[0077] It should be noted that the coefficient of dynamic friction between the heat-shrinkable plastic part 40a and the preform 10a can be determined at 23°C according to the method of JIS-K7125.

[0078] In addition, the preform 10a is preferably made of polyethylene terephthalate, and the coefficient of dynamic friction between the plastic part 40a and the polyethylene terephthalate is preferably the same as described above.

[0079] (Coefficient of static friction for heat-shrinkable plastic parts)

[0080] The coefficient of static friction between the heat-shrinkable plastic component 40a and the preform 10a (described later) is preferably 1.1 or less, more preferably 1.0 or less, and even more preferably 0.8 or less. There is no particular limitation on the lower limit of the coefficient of static friction, but it is preferably 0.3 or more, more preferably 0.4 or more. By ensuring that the coefficient of static friction between the heat-shrinkable plastic component and the preform is within the above range, it is easier to determine the insertion position when inserting the preform into the heat-shrinkable plastic component.

[0081] Regarding the static friction coefficients of the heat-shrinkable plastic component 40a and the preform 10a, the two surfaces (the inner and outer surfaces in the case of a tubular shape) can be the same or different, as long as at least one surface meets the above conditions. In the case that the heat-shrinkable plastic component 40a is tubular, it is preferable that at least the inner surface meets the above conditions.

[0082] It should be noted that the static friction coefficient between the heat-shrinkable plastic part 40a and the preform 10a can be determined at 23°C according to the method of JIS K7125.

[0083] In addition, the preform 10a is preferably made of polyethylene terephthalate, and the static friction coefficient between the plastic part 40a and the polyethylene terephthalate is preferably the same as described above.

[0084] The specific gravity of the heat-shrinkable plastic component 40a at 23°C is preferably less than 1.0, more preferably less than 0.99. By making the specific gravity of the heat-shrinkable plastic component 40a less than 1, the difference in specific gravity between the two can be used to separate the heat-shrinkable plastic component 40a from the container body 10.

[0085] <Manufacturing Method of Heat-Shrinkable Plastic Parts 40a>

[0086] In one embodiment, the heat-shrinkable plastic component 40a can be manufactured using various methods known to the public. Without particular limitation, the following method is preferred: melting various raw materials using a single-screw extruder, extruding an unstretched tube using a ring die or a multi-ring die, and then stretching it to produce a seamless heat-shrinkable tube. Other methods include: forming a tube by bonding a film extruded and stretched using a T-die through heat bonding, fusion bonding, or adhesive bonding; and forming a tube by bonding the aforementioned film in a spiral shape; etc.

[0087] Here, a method for producing a heat-shrinkable tube by extruding an unstretched tube using a ring die or a multi-ring die and then stretching it is described in more detail. The various raw materials described above are heated and melted using a melt extrusion apparatus, continuously extruded from a ring die or a multi-ring die, and then forcibly cooled to form an unstretched tube. Forced cooling can be achieved by immersion in cold water, using cold air, etc. Immersion in cold water is the most efficient and effective method. The unstretched tube can be continuously fed to the next stretching process; alternatively, it can be wound into a roll and used as the blank for the next stretching process. From the perspectives of manufacturing efficiency and thermal efficiency, the method of continuously feeding the unstretched tube to the next stretching process is preferred.

[0088] The resulting unstretched tube is pressurized with compressed gas from the inside and then stretched. The stretching method is not particularly limited; for example, while applying pressure from compressed gas to the inside of the unstretched tube from one end, it is fed out at a certain speed, then heated by warm water or an infrared heater, and passed through a cooled cylindrical tube, undergoing a fixed-ratio stretching, specifying the stretching ratio in the direction perpendicular to the flow direction (TD). Temperature conditions are adjusted according to the method of stretching at appropriate positions in the cylindrical tube. The stretched tube, cooled in the cylindrical tube, is held by a pair of clamping rollers, and pulled and wound as a stretched tube while maintaining the stretching tension. Stretching can be performed in either the flow direction (MD) or the direction perpendicular to the flow direction (TD), but simultaneous stretching is preferred.

[0089] The stretching conditions are adjusted according to the characteristics of the resin composition used or the target heat shrinkage rate, etc.

[0090] The stretching ratio in the flow direction (MD) is determined by the ratio of the feed speed of the unstretched tube to the speed of the stretching clamping rollers, while the stretching ratio in the direction perpendicular to the flow direction (TD) is determined by the ratio of the unstretched outer diameter to the stretching outer diameter. Alternatively, a stretching and pressurizing method can be employed that maintains the internal pressure of compressed gas sealed between the clamping rollers, clamping both the unstretched tube's feed side and the stretching tube's traction side.

[0091] The heat-shrinkable tube (heat-shrinkable plastic component) of the present invention is manufactured by stretching an unstretched tube along both the direction perpendicular to the flow direction (TD) and the flow direction (MD). The stretching ratio in the direction perpendicular to the flow direction (TD) is preferably 1.4 to 2.0 times, more preferably 1.5 to 1.8 times. Alternatively, the tube may be unstretched in the flow direction (MD), but it is preferably obtained by stretching it at a ratio in the range of 1.02 to 1.25 times, preferably 1.17 times or less.

[0092] Here, if the stretch ratio of the heat shrinkable tube in the direction perpendicular to the flow direction (TD) is 1.4 times or more, sufficient shrinkage amount can be obtained for coating the preform. Furthermore, if it is 2.0 times or less, uneven shrinkage of the tube caused by temperature inconsistencies within the coating furnace or intrusion into the furnace can be suppressed. On the other hand, if the stretch ratio of the heat shrinkable tube in the flow direction (MD) is 1.25 times or less, the shrinkage amount in the flow direction (MD) is moderate, preventing deviation due to shrinkage during coating processing. This reduces the remaining length of the tube before coating (before shrinkage) and thus also suppresses cost increases.

[0093] The shrinkage rate of the heat-shrinkable plastic part manufactured as described above is preferably 3% to 20% in the flow direction (MD), more preferably 5% to 15%. The shrinkage rate in the direction perpendicular to the flow direction (TD) is preferably 30% to 50%, more preferably 35% to 45%. By making the shrinkage rates of the heat-shrinkable plastic part in the flow direction (MD) and the direction perpendicular to the flow direction (TD) within the above ranges, when the heat-shrinkable plastic part is coated and processed into a preform, the heat-shrinkable plastic part fits tightly from the opening to the bottom of the preform, and the finish becomes good.

[0094] <Composite Preform 70>

[0095] The composite preform 70 of the present invention is characterized in that it comprises a preform 10a and a heat-shrinkable plastic component 40a disposed in close contact with the outer side of the preform 10a.

[0096] like Figure 3 and 4 As shown, the preform 10a of the composite preform 70 includes an opening 11a, a main body 20a connected to the opening 11a, and a bottom 30a connected to the main body 20a. The opening 11a corresponds to the opening 11 of the container body 10 described later and has a shape that is substantially the same as the opening 11.

[0097] Furthermore, the main body 20a corresponds to the neck 13, shoulder 12, and main body 20 of the container body 10, and has an approximately cylindrical shape. The bottom 30a corresponds to the bottom 30 of the container body 10, and has an approximately hemispherical shape.

[0098] In one embodiment, the preform 10a is made of a resin material, such as polyamide resins, polyester resins, polyolefin resins, cellulose resins, and vinyl resins. Polyethylene terephthalate is more preferably used. Furthermore, the preform 10a may also contain two or more of the aforementioned resin materials.

[0099] In addition, the preform 10a may also contain colorants such as red, blue, yellow, green, brown, black, and white. However, considering the ease of recycling, it is preferable to not contain these colorants and to be colorless and transparent.

[0100] In addition, the preform 10a may contain additives such as plasticizers, fillers, UV stabilizers, anti-coloring agents, fluorescent whitening agents, matting agents, deodorizers, flame retardants, weathering agents, antistatic agents, linear friction reducers, slip agents, release agents, antioxidants, ion exchangers, dispersants, and UV absorbers.

[0101] In addition, the preform 10a can have a single-layer structure or a multi-layer structure.

[0102] For example, the intermediate layer can be made of a resin with gas barrier properties or a resin with light-shielding properties, such as nylon MXD-6, nylon MXD-6+ fatty acid salt, polyglycolic acid (PGA), ethylene-vinyl alcohol copolymer (EVOH), or polyethylene naphthalate (PEN), to form a preform 10a consisting of 3 or more layers.

[0103] The outer diameter of the preform 10a is preferably 20 mm or more and 50 mm or less, more preferably 25 mm or more and 45 mm or less. By making the outer diameter of the preform 10a within the above-mentioned range, it is easier to insert it into the heat-shrinkable plastic part 40a, thereby improving the productivity of the composite preform 70.

[0104] The material and thickness constituting the heat-shrinkable plastic component 40a are as described above.

[0105] like Figure 3 As shown, the heat-shrinkable plastic component 40a is installed in a manner that is not adhered to the outer surface of the preform 10a, and is fitted to the preform 10a to a degree that it does not move or rotate, or to a degree that it will not fall off due to its own weight. The plastic component 40a is disposed around the entire circumferential area of ​​the preform 10a in a manner that surrounds it, and has a circular horizontal cross section.

[0106] Alternatively, the heat-shrinkable plastic component 40a may have one end heat-pressed to form the bottom 43a (see reference). Figure 5 ).

[0107] <Manufacturing Method of Composite Preform 70>

[0108] The method for manufacturing the composite preform 70 includes:

[0109] The process of preparing the preform 10a and the heat-shrinkable plastic part 40a;

[0110] The process of inserting the preform 10a into one end of the heat-shrinkable plastic component 40a; and

[0111] The process of heating the heat-shrinkable plastic part 40a to shrink it and seal it with the preform 10a.

[0112] In another embodiment, the method for manufacturing the composite preform 70 of the present invention includes a step of heat-pressing one end of a heat-shrinkable plastic component 40a.

[0113] (Preparation process for preform 10a and heat-shrinkable plastic part 40a)

[0114] The preform 10a can be manufactured by injection molding the aforementioned resin material using a known injection molding apparatus.

[0115] Furthermore, the method for manufacturing the heat-shrinkable plastic component 40a is as described above.

[0116] (Insertation process)

[0117] In the insertion process, the preform 10a is inserted from one end of the heat-shrinkable plastic component 40a. This process can be performed manually or mechanically. It should be noted that there are no restrictions on whether the insertion process is performed by moving either the heat-shrinkable plastic component 40a or the preform 10a, or by moving both of them.

[0118] Insertion is performed by inserting the bottom 30a of the preform 10a into the opening at one end of the heat-shrinkable plastic component 40a. The extent of insertion varies depending on the length of the preform 10a and the length of the heat-shrinkable plastic component 40a, or the desired product shape, but... Figure 5 Except for the case where one end of the heat-shrinkable plastic component 40a is heat-pressed, the component 40a is inserted from the opening at the other end of the component 40a to the extent that the bottom 30a of the preform 10a is exposed.

[0119] (Heating process)

[0120] The heating method for the heat-shrinkable plastic part 40a is not particularly limited, and infrared radiation, hot air, or other suitable methods can be used. The heating temperature is preferably 60°C to 250°C, 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 part 40a during heating, not the set temperature of infrared radiation, hot air, etc. It should also be noted that this heating process is not mandatory. For example, if the preform 10a and the heat-shrinkable plastic part 40a are tightly bonded to the point that no positional shift occurs, a heating process is not necessarily required.

[0121] (Hot pressing process)

[0122] In one embodiment, the method of the present invention may include a step of heat-pressing one end of a heat-shrinkable plastic component 40a. By including this step, the heat-shrinkable plastic component 40a can completely cover the bottom 30a of the preform 10a, and even the bottom 30a of the blow-molded container body 10.

[0123] Specifically, to make the length X of the heat-shrinkable plastic component 40a (refer to...) Figure 6 The length Y of the preform 10a from the neck 13a to the bottom 30a is longer than the length of the preform 10a (refer to the length of the neck 13a to the bottom 30a). Figure 7 The bottom 43a is formed by heat-shrinkable plastic component 40a having a blank portion 80a at one end and heat-pressing the blank portion 80a.

[0124] The length of the blank area 80a is preferably 3mm or more, and more preferably 5mm or more and 20mm or less.

[0125] There are no particular limitations on the hot pressing method. As long as it can clamp and press the blank area that has been heated by infrared rays or hot air, it is acceptable. There are no particular limitations. For example, a tool made of metal or heat-resistant resin (hereinafter referred to as a "pressing tool" as appropriate) can be used, and combinations of these tools are also acceptable. The surface of the pressing tool can be flat or partially or entirely embossed.

[0126] Furthermore, the crimping tool may also have a heating mechanism on its surface. This further improves the crimping strength of the blank portion 80a. The heating temperature of the surface of the crimping tool is preferably, for example, 100°C or higher and 250°C or lower.

[0127] The preferred pressure for crimping is 50 N / cm. 2 Above 1000 N / cm 2 The following, or more preferably, is 100 N / cm 2 Above 500N / cm 2 the following.

[0128] The temperature of the heat-shrinkable plastic component 40a during pressing also depends on the material, and is preferably above 80°C and below 200°C.

[0129] <Composite Container 10A>

[0130] The composite container 10A of the present invention is a blow-molded product of the aforementioned composite preform 70, such as... Figures 8-10 As shown, the feature is that it includes a container body 10 and a heat-shrinkable plastic component 40 that is tightly fitted to the outside of the container body 10.

[0131] like Figures 8-10 As shown, the container body 10 has a mouth 11, a neck 13 located below the mouth 11, a shoulder 12 located below the neck 13, a main body 20 located below the shoulder 12, and a bottom 30 located below the main body 20.

[0132] In one embodiment, the opening 11 has a threaded portion 14 that is mounted on a cover (not shown) and a flange portion 17 disposed below the threaded portion 14.

[0133] In one embodiment, the neck 13 is located between the flange 17 and the shoulder 12, and has an approximately cylindrical shape with a generally uniform diameter. Additionally, the shoulder 12 is located between the neck 13 and the main body 20, and has a shape in which the diameter gradually increases from the neck 13 side towards the main body 20 side.

[0134] In another embodiment, the main body 20 has a cylindrical shape with a generally uniform diameter. However, it is not limited to this; the main body 20 may also have a polygonal cylindrical shape such as a quadrilateral cylindrical shape or an octagonal cylindrical shape, and the main body 20 may also have a cylindrical shape with an uneven horizontal cross-section from top to bottom.

[0135] in addition, Figures 8-10 The main body 20 of the container body 10 shown has a generally flat surface, but is not limited thereto; the main body 20 may also have a panel or groove or other irregularities.

[0136] In another embodiment, the bottom 30 has a central recess 31 and a grounding portion 32 disposed around the recess 31. It should be noted that the shape of the bottom 30 is not particularly limited, and can be formed into a petal shape, a round bottom shape, etc., depending on the contents to be filled.

[0137] Furthermore, the thickness of the container body 10 in the main body 20 is not limited to this, and can be as thin as, for example, about 50μm to 250μm. In addition, the weight of the container body 10 is not limited to this, for example, when the contents of the container body 10 are 500mL, it can be set to 10g to 20g.

[0138] The container body 10 can be, for example, a bottle with a full-fill capacity of 100 mL to 2000 mL. Alternatively, the container body 10 can also be a large bottle with a full-fill capacity of, for example, 10 L to 60 L.

[0139] like Figure 8 and 9 As shown, the heat-shrinkable plastic component 40 can be configured to cover the shoulder 12 and body 20 of the container body 10, excluding the mouth 11, neck 13 and bottom 30.

[0140] In addition, after heat-pressing one end of the heat-shrinkable plastic component 40a as described above, it is blow-molded to form a structure that covers the bottom 30 of the container body 10 (see reference). Figure 10 ).

[0141] Furthermore, the thickness of the heat-shrinkable plastic component 40 is not limited to this, and can be set to approximately 5 μm to 100 μm when installed on the container body 10.

[0142] The heat-shrinkable plastic component 40 is not fused or bonded to the container body 10, and therefore can be separated (peeled) from the container body 10.

[0143] As a method for separating (peeling) the heat-shrinkable plastic component 40 from the container body 10, for example, the heat-shrinkable plastic component 40 can be cut off using a knife or the like; or a cutting line can be pre-set on the heat-shrinkable plastic component 40, and the heat-shrinkable plastic component 40 can be peeled off along the cutting line. By using the above methods, the heat-shrinkable plastic component 40 can be separated and removed from the container body 10, so that the colorless and transparent container body 10 can be recycled in the same way as before.

[0144] <Manufacturing Method of Composite Container 10A>

[0145] The composite container 10A is manufactured by the following steps:

[0146] The process of heating the composite preform 70; and

[0147] In a blow molding die, a heated composite preform 70 is blow molded, thereby expanding the preform 10a and the heat-shrinkable plastic part 40a as a single unit.

[0148] In one embodiment, the method of the present invention includes a step of forming an image on a heat-shrinkable plastic part 40 after blow molding.

[0149] The following is based on Figure 11 Sections (a) to (d) provide a more detailed description of the manufacturing method of the composite container 10A of the present invention.

[0150] First, the composite preform 70 is heated using heating device 51 (see reference). Figure 11 (a) At this time, the composite preform 70 is rotated with its opening 11a facing downwards while being heated evenly in the circumferential direction by the heating device 51. The heating temperature of the preform 10a and the heat-shrinkable plastic part 40a in this heating process can be, for example, 90°C to 130°C.

[0151] In addition, the heating can be carried out appropriately using infrared rays or hot air.

[0152] Next, the composite preform 70, heated by the heating device 51, is sent to the blow molding die 50 (see reference). Figure 11 (b)

[0153] The composite container 10A is formed using the blow molding die 50.

[0154] In one embodiment, the blow molding die 50 consists of a pair of separate main body dies 50a and 50b and a bottom die 50c (see reference). Figure 11 (b) Figure 11 In (b), the pair of main body molds 50a and 50b are separated from each other, and the bottom mold 50c is lifted upward. In this state, the composite preform 70 is inserted between the pair of main body molds 50a and 50b.

[0155] Next, after the bottom mold 50c descends, a pair of main body molds 50a and 50b are closed, forming a sealed blow molding mold 50 with the main body molds 50a and 50b and the bottom mold 50c. Then, air is forced into the preform 10a, and the composite preform 70 is subjected to biaxial stretch blow molding. Thus, the container body 10 (see reference) is obtained from the preform 10a within the blow molding mold 50. Figure 11 (c) During this period, 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, within the blow molding mold 50, the preform 10a of the composite preform 70 and the heat-shrinkable plastic component 40a expand as a single unit. As a result, the preform 10a and the heat-shrinkable plastic component 40a become a single unit and are given a shape corresponding to the inner surface of the blow molding mold 50.

[0156] Thus, a composite container 10A is obtained, comprising a container body 10 and a heat-shrinkable plastic component 40 disposed on the outer surface of the container body 10.

[0157] Next, as Figure 11 As shown in (d), a pair of main body molds 50a, 50b and bottom mold 50c are separated from each other, and the composite container 10A is removed from the blow molding mold 50.

[0158] Example

[0159] The invention will now be described in more detail by way of examples, but the invention is not limited to these examples.

[0160] <Example 1>

[0161] Himilan 1706 (manufactured by Dupont-Mitsui Polychemical Co., Ltd., with MFR 0.9 g / 10 min and storage modulus of 3.8 × 10⁻⁶ at 25°C) was extruded using a single-screw extruder with a ring die as the ionomer resin (A). 8Win-Tech WFX4TA (manufactured by Japan Polypropylene Co., Ltd., metallocene polypropylene, MFR 7.0 g / 10 min, storage modulus 1.0 × 10⁻⁶ Pa), 95% by mass, as an olefin-based resin (B), is a metallocene-based polypropylene with a storage modulus of 1.0 × 10⁻⁶ at 25°C. 9 A mixture of 5% by mass (Pa) was melt-extruded to form an unstretched tube with an inner diameter of 16.6 mm. The tube was then heated with hot water and stretched by applying compressed gas from the inside, thus producing a bottomless cylindrical heat-shrinkable plastic component. It should be noted that the heat-shrinkable plastic component has an inner diameter of 28.7 mm and a thickness of 307 μm.

[0162] <Example 2>

[0163] The outermost layer uses a mixture of 95% by mass of Himilan 1706 as ionomer resin (A) and 5% by mass of Win-Tech WFX4TA as olefin resin (B). The adhesive layer uses 100% by mass of polyolefin adhesive resin (Admer SF731, manufactured by Mitsui Chemicals Co., Ltd.). The middle layer uses a mixture of 100% by mass of ethylene-vinyl alcohol copolymer (EVALSP482B, manufactured by KURARAY Co., Ltd.) as a gas barrier layer. Using a 5-layer annular die, the three materials are melt-extruded separately through a single screw extruder to form an unstretched tube with an inner diameter of 18.3 mm. Then, the unstretched tube is heated with hot water and stretched by pressurizing compressed gas from the inside of the tube, thereby producing a bottomless cylindrical heat-shrinkable plastic part. It should be noted that the inner diameter of the heat-shrinkable plastic part is 28.7 mm and the thickness is 345 μm (outermost layer 132 μm, adhesive layer 17 μm, intermediate layer 47 μm).

[0164] <Comparative Example 1>

[0165] Himilan 1855 (manufactured by Dupont-Mitsui Polychemical Co., Ltd., MFR 1.0 g / 10 min, storage modulus 1.2 × 10⁻⁶) as ionomer resin (A) was extruded using a ring die and a single-screw extruder. 8 A mixture of 95% by mass of (Pa) and 5% by mass of Win-TechWFX4TA (as olefin resin (B)) was melt-extruded to form an unstretched tube with an inner diameter of 16.6 mm. The unstretched tube was then heated with hot water and stretched by applying compressed gas from the inside, thereby producing a bottomless cylindrical heat-shrinkable plastic component. It should be noted that the heat-shrinkable plastic component has an inner diameter of 28.7 mm and a thickness of 298 μm.

[0166] <Comparative Example 2>

[0167] Using a ring die, a mixture of Himilan 1706 (as ionomer resin (A)) was melt-extruded using a single-screw extruder to form an unstretched tube with an inner diameter of 16.9 mm. This unstretched tube was then heated with hot water and stretched by applying compressed gas from the inside, thereby producing a bottomless cylindrical heat-shrinkable plastic component. It should be noted that the heat-shrinkable plastic component has an inner diameter of 28.7 mm and a thickness of 310 μm.

[0168] <Storage Modulus>

[0169] The storage modulus of the heat-shrinkable plastic parts obtained in the above embodiments and comparative examples was determined by measuring the storage modulus of the test pieces at 25°C according to the method of JIS K7244-4. The measurement results are summarized in Table 1.

[0170] <Coefficient of kinetic friction, coefficient of static friction>

[0171] The dynamic and static friction coefficients between the bottomless cylindrical heat-shrinkable plastic parts obtained in the examples and comparative examples and the preforms were measured at 23°C according to the method of JIS K7125.

[0172] Specifically, a bottomless cylindrical heat-shrinkable plastic component is cut to form a 40mm × 200mm heat-shrinkable plastic component, and a polyethylene terephthalate preform (55mm long × 22mm wide × 11mm radius) is cut into a semi-cylindrical shape. The bottomless cylindrical heat-shrinkable plastic component is fixed on a horizontal test table with its inner surface facing upwards. The cross-section of the semi-cylindrical polyethylene terephthalate preform is facing upwards, and its outer surface is placed on the heat-shrinkable plastic component. A straight force is applied along the longitudinal direction of the polyethylene terephthalate preform, and the dynamic and static friction coefficients are measured.

[0173] Specific gravity

[0174] The specific gravity of the heat-shrinkable plastic parts obtained in the examples and comparative examples was determined at 23°C according to the method of JIS Z8807.

[0175] <Insertion ease test>

[0176] Using an injection molding machine, materials made of polyethylene terephthalate (PET) are produced. Figure 3 , 4 The image shows a bottomed cylindrical preform. It should be noted that the outer diameter of the preform is 26 mm.

[0177] The examples and comparative examples obtained Figure 3 , 4 The opening at one end of the bottomless cylindrical heat-shrinkable plastic component shown is inserted into the bottom side of the preform manufactured as described above. The time until the bottom of the preform is exposed from the other end is measured, and the evaluation is carried out according to the following evaluation criteria. The evaluation results are summarized in Table 1.

[0178] (Evaluation Criteria)

[0179] A: The above time is less than 0.5 seconds, which makes it easy to insert the preform into the heat-shrinkable plastic part.

[0180] NG: The above time is more than 0.5 seconds.

[0181] [Table 1]

[0182]

[0183] Symbol Explanation

[0184] 10. Container body

[0185] 10A Composite Container

[0186] 10a preform

[0187] 11. Mouth

[0188] 11a Mouth

[0189] 12 Shoulders

[0190] 13 Neck

[0191] 20 Main body

[0192] 20a Main body

[0193] 30 Bottom

[0194] 30a bottom

[0195] 40. Heat-shrinkable plastic parts (after blow molding)

[0196] 40a Heat-shrinkable plastic parts (before blow molding)

[0197] 50 Blow Molding Die

[0198] 70 Composite Preform

Claims

1. A composite container, which is a blow-molded composite preform, wherein, The composite preform comprises: A preform comprising 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 fit tightly against the outer side of the preform. For the heat-shrinkable plastic component of the composite preform, it at least comprises a layer containing an ionomer resin (A) and a polypropylene resin (B) as essential components, wherein the content of the ionomer resin (A) in the layer is 40% by mass or more and 99% by mass or less, the content of the polypropylene resin (B) is 1% by mass or more and 60% by mass or less, and the storage modulus of the ionomer resin (A) at 25°C is 1.5 × 10⁻⁶. 8 The storage modulus of the polypropylene resin (B) at 25°C is 7.0 × 10⁻⁶ Pa or higher. 8 Pa ~ 2.0 × 10 9 Pa and the melt flow rate, measured according to ISO 1133 at a temperature of 230°C and a load of 21.17 N, is 4 g / 10 min to 9 g / 10 min, and the storage modulus at 25°C is 4.0 × 10⁻⁶. 8 Pa or higher, and the coefficient of dynamic friction between the material and the preform is 1.1 or lower. The thickness of the heat-shrinkable plastic component in the blow-molded composite container is 5 μm to 100 μm. The static friction coefficient between the heat-shrinkable plastic component in the composite preform and the preform is less than 1.

1.

2. The composite container as claimed in claim 1, wherein, The specific gravity of the heat-shrinkable plastic component in the composite preform is less than 1.

0.

3. The composite container as described in claim 1 or 2, wherein, The content of the ionomer resin (A) is greater than 60% by mass and less than 99% by mass. The preform is polyethylene terephthalate.

4. The composite container as described in claim 1 or 2, wherein, The storage modulus of the heat-shrinkable plastic component in the composite preform is 4.0 × 10⁻⁶ at 25°C. 8 Pa ~ 1.0 × 10 9 Pa.

5. The composite container as described in claim 3, wherein, The storage modulus of the heat-shrinkable plastic component in the composite preform is 4.0 × 10⁻⁶ at 25°C. 8 Pa ~ 1.0 × 10 9 Pa.

6. A composite container, which is a blow-molded composite preform, wherein, The composite preform comprises: A preform comprising 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 fit tightly against the outer side of the preform. For the heat-shrinkable plastic component of the composite preform, it at least comprises a layer containing an ionomer resin (A) and an olefin resin (B) as essential components, wherein the content of the ionomer resin (A) in the layer is 40% by mass or more and 99% by mass or less, the content of the olefin resin (B) is 1% by mass or more and 60% by mass or less, and the storage modulus of the ionomer resin (A) at 25°C is 1.5 × 10⁻⁶. 8 Above Pa, the storage modulus of the olefin resin (B) at 25°C is 7.0 × 10⁻⁶. 8 Pa ~ 2.0 × 10 9 The energy storage modulus at 25℃ is 4.0 × 10 Pa. 8 Pa or higher, and the coefficient of dynamic friction between the material and the preform is 1.1 or lower. The thickness of the heat-shrinkable plastic component in the blow-molded composite container is 5 μm to 100 μm. The static friction coefficient between the heat-shrinkable plastic component and the preform in the composite preform is below 1.

1. The shrinkage rate of the heat-shrinkable plastic component in the composite preform is 3% to 20% in the flow direction MD and 30% to 50% in the direction perpendicular to the flow direction TD.

7. The composite container as claimed in claim 1 or 2, wherein, The thickness of the layer comprising the ionomer resin (A) and the polypropylene resin (B) in the heat-shrinkable plastic component of the composite preform is 200 μm to 500 μm.

8. The composite container as claimed in claim 3, wherein, The thickness of the layer comprising the ionomer resin (A) and the polypropylene resin (B) in the heat-shrinkable plastic component of the composite preform is 200 μm to 500 μm.

9. The composite container as claimed in claim 6, wherein, The thickness of the layer comprising the ionomer resin (A) and the olefin resin (B) in the heat-shrinkable plastic component of the composite preform is 200 μm to 500 μm.

10. A composite container, which is a blow-molded composite preform, wherein, The composite preform comprises: A preform comprising 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 fit tightly against the outer side of the preform. For the heat-shrinkable plastic component of the composite preform, it at least comprises a layer containing an ionomer resin (A) and an olefin resin (B) as essential components, wherein the content of the ionomer resin (A) in the layer is 40% by mass or more and 99% by mass or less, the content of the olefin resin (B) is 1% by mass or more and 60% by mass or less, and the storage modulus of the ionomer resin (A) at 25°C is 1.5 × 10⁻⁶. 8 Above Pa, the storage modulus of the olefin resin (B) at 25°C is 7.0 × 10⁻⁶. 8 Pa ~ 2.0 × 10 9 The energy storage modulus at 25℃ is 4.0 × 10 Pa. 8 Pa or higher, and the coefficient of dynamic friction between the material and the preform is 1.1 or lower. The thickness of the heat-shrinkable plastic component in the blow-molded composite container is 5 μm to 100 μm. The static friction coefficient between the heat-shrinkable plastic component and the preform in the composite preform is below 1.

1. The heat-shrinkable plastic component in the composite preform has, from the inside, a layer containing the ionomer resin (A) and the olefin resin (B), a gas barrier layer, and another layer containing the ionomer resin (A) and the olefin resin (B).

11. The composite container of claim 10, wherein, An adhesive layer is also provided between the layer containing the ionomer resin (A) and the olefin resin (B) and the gas barrier layer.

12. The composite container of claim 10, wherein, The thickness of the layers containing the ionomer resin (A) and the olefin resin (B) in the composite preform is 40 μm to 200 μm, respectively.

13. The composite container of claim 10, wherein, The thickness of the gas barrier layer in the composite preform is 20 μm to 60 μm.

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