Blow molding method and container

Abstract

To enable a container to be easily manufactured and, after use, to be disposed of in a form suitable for recycling.SOLUTION: An original film 21 is folded in half, and the original film folded in half is placed in a blow molding die 30, and a resulting material is blow molded in the blow molding die 30, thereby obtaining a connected bottle 10A including a plurality of containers 10. The original film 21 includes an uncolored and unprinted PET film 22 and a functional film 24.SELECTED DRAWING: Figure 1B

Description

[Technical field]

[0001] The present disclosure relates to a blow molding method for producing a container and the container. [Background technology]

[0002] Conventionally, containers having an opening and a container body are known, and the inside of the container is filled with a liquid. Such containers are generally obtained by preparing a preform, heating the preform, and then mounting the preform in a mold, and then supplying air into the preform to expand the preform in the mold.

[0003] In such a method for manufacturing a container, it is necessary to first prepare a preform to be placed in a mold, which makes the manufacturing process complicated.

[0004] On the other hand, after the content liquid is removed from the container and used, the container is discarded.

[0005] Currently, the recycling of containers has become mandatory, and there is a demand to dispose of containers in a form suitable for recycling. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-112848 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present disclosure has been made in consideration of these points, and aims to provide a blow molding method and a container that can easily produce a container and that can be disposed of after use in a form suitable for recycling. [Means for solving the problem]

[0008] The present disclosure relates to a blow molding method comprising the steps of preparing a film roll, folding the film roll in half and placing it in a blow molding die, and supplying air into the film roll placed in the blow molding die to form a container having an opening and a container body, wherein the film roll has an uncolored and unprinted PET film.

[0009] The present disclosure is a blow molding method, wherein the raw film further has a functional film releasably provided on the outer surface of the PET film.

[0010] The present disclosure is a blow molding method further comprising a step of filling the container with a content through an opening of the container.

[0011] The present disclosure is a blow molding method further comprising the step of heat sealing the opening of the container.

[0012] The present disclosure is a blow molding method, in which the functional film of the film raw material is made of a printed PE film or PP film.

[0013] The present disclosure is a blow molding method, wherein the raw film further has a coating layer provided on the inner surface of the PET film or between the PET film and the functional film.

[0014] The present disclosure is a blow molding method in which a plurality of the containers are provided, and adjacent container bodies are connected to each other.

[0015] Disclosed is a blow molding method in which the connected containers are covered together with a shrink wrap.

[0016] Disclosed is a blow molding method that provides a shrink wrap over the exterior surface of the container.

[0017] The present disclosure is a blow molding method further comprising a step of treating the PET film and the functional film separately after peeling the functional film from the PET film of the container.

[0018] The present disclosure relates to a container having an opening and a container body, the container having an uncolored and unprinted PET film and a functional film releasably provided on the outer surface of the PET film.

[0019] The present disclosure relates to a container, wherein the functional film is made of a PE film or a PP film.

[0020] The present disclosure is a container having a coating layer provided on the inner surface of the PET film or between the PET film and the functional film.

[0021] The present disclosure relates to a container in which a plurality of the containers are provided, and adjacent container bodies are connected to each other.

[0022] The present disclosure is a container having a shrink wrap covering an exterior surface of the container.

[0023] The present disclosure is a container in which the connected containers are covered together with shrink wrap. Effect of the Invention

[0024] As described above, according to the present disclosure, containers can be manufactured easily and simply, and after use, the containers can be disposed of in a form suitable for recycling. [Brief description of the drawings]

[0025] [Figure 1A] FIG. 1A is a cross-sectional view showing a blow molding mold used in the blow molding method according to the present disclosure. [Figure 1B] FIG. 1B is a cross-sectional view showing a container produced within a blow mold. [Figure 1C]FIG. 1C is a diagram showing a state in which a content liquid is being filled into the container removed from the blow molding die. [Figure 1D] FIG. 1D is a diagram showing a state in which a cap is attached to an opening of a container. [Figure 1E] FIG. 1E is a diagram showing the state in which the opening of the container is directly heat-sealed. [Figure 1F] FIG. 1F is an enlarged view of FIG. 1E showing the opening of the container. [Figure 2A] FIG. 2A is a diagram showing preparation of a film roll. [Figure 2B] FIG. 2B is a diagram showing the state in which the original film is folded in half. [Figure 2C] FIG. 2C is a perspective view showing the appearance of a blow molding die. [Figure 3A] FIG. 3A shows a connected bottle made up of multiple containers. [Figure 3B] FIG. 3B shows the connected bottles covered with shrink wrap. [Figure 4A] FIG. 4A is a cross-sectional view showing an original film. [Figure 4B] FIG. 4B is a cross-sectional view showing another example of the original film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] A blow molding method and a container according to the present disclosure will be described below with reference to the drawings. Figures 1A to 4 are diagrams showing an embodiment of a blow molding method and a container according to the present disclosure.

[0027] First, a container according to the present disclosure will be described with reference to Fig. 3A. As shown in Fig. 3A and Fig. 3B, container 10 includes container body 11 and opening 12 provided at the top of container body 11, with cap 15 attached to opening 12 by heat sealing. Container body 11 of container 10 also includes trunk 11a, bottom 11b, and shoulder 11c.

[0028] The container 10 thus constructed is filled with a liquid content 20, such as a beverage.

[0029] In this embodiment, a plurality of, for example, five, containers 10 are provided, and the five containers 10 are connected to one another via peripheral portions 19 provided on the periphery of the container body 11.

[0030] That is, each container 10 has a peripheral portion 19 on the periphery excluding the opening 12, and the containers 10 are connected to each other via peripheral portions 19a located between the containers 10. The five containers 10 connected to each other form a connected bottle 10A.

[0031] In the present embodiment, an example has been shown in which five containers 10 are connected to each other to produce a connected bottle 10A, but this is not limiting, and individual containers 10 can also be produced one by one. In this case, each individual container 10 has a container body 11, an opening 12 provided at the top of the container body 11, and a peripheral portion 19 provided on the periphery of the container body 11. Furthermore, each individual container 10 is filled with a content liquid 20.

[0032] Incidentally, as shown in FIG. 3A, the container body 11 of the container 10 has a printed portion 17 formed on the surface thereof by printing.

[0033] As described above, the linked bottle 10A is obtained by linking five containers 10, and the linked bottle 10A can be entirely covered with shrink wrap 25. By covering the linked bottles 10A with shrink wrap 25 in this way, the linked bottles 10A can be packaged together (see FIG. 3B).

[0034] In this specification, the terms "upper" and "lower" refer to the upper and lower sides, respectively, of the container 10 when it is held upright (FIG. 3A).

[0035] The container 10 shown in Figs. 3A and 3B is obtained by subjecting a raw film 21 to uniaxial stretch blow molding using a blow molding die 30, thereby expanding the raw film 21, as described below.

[0036] As shown in Fig. 4A, the original film roll 21 has a PET film (polyethylene terephthalate film) 22, a coating layer 23 located on the inner surface side of the PET film 22, and a functional film 24 located on the outer surface side of the PET film 22. Alternatively, as shown in Fig. 4B, the original film roll 21 may have a PET film 22, a functional film 24 located on the outer surface side of the PET film 22, and a coating layer 23 provided between the PET film 22 and the functional film 24.

[0037] Next, the film web 21 from which the container 10 is manufactured will be described in more detail.

[0038] (PET film 22) An uncolored and unprinted PET film is used as the PET film 22 in the film roll 21. As described later, this PET film 22 is easily peeled off (separated) from the functional film 24 provided on the outer surface of the PET film 22 in a peelable manner. The PET film 22 can be discarded separately from the functional film 24. Here, the uncolored and unprinted PET film 22 refers to a PET film that has neither a colored layer or colored region, nor a printed layer or printed region.

[0039] (Functional Film 24) The functional film 24 is preferably made of, for example, a printed PE film (polyethylene film) or a printed PP film (polypropylene film). In this manner, in the present embodiment, an uncolored and unprinted PET film is used as the PET film 22 of the original film roll 21, so that the entire container 10 can be provided with a printing function by using a PE film or PP film with a printing function.

[0040] In the present embodiment, the functional film 24 may contain the following resin material having a printing function.

[0041] For example, PE, PP, PEN, poly-4-methylpentene-1, polystyrene, AS resin, ABS resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, polyvinyl butyral, diallyl phthalate resin, fluororesin, polymethyl methacrylate, polyacrylic acid, polymethyl acrylate, polyacrylonitrile, polyacrylamide, polybutadiene, polybutene-1, polyisoprene, polychloroprene, ethylene propylene rubber, butyl rubber, nitrile rubber, acrylic rubber, silicone rubber, fluororubber, nylon 6, nylon 6,6, nylon MX The resin material may include resin materials such as D6, aromatic polyamide, polycarbonate, polyethylene terephthalate, polyethylene butylene terephthalate, ethylene polynaphthalate, U polymer, liquid crystal polymer, modified polyphenylene ether, polyether ketone, polyether ether ketone, unsaturated polyester, alkyd resin, polyimide, polysulfone, polyphenylene sulfide, polyether sulfone, silicone resin, polyurethane, phenol resin, urea resin, polyethylene oxide, polypropylene oxide, polyacetal, epoxy resin, and ionomer resin, and these resin materials may be printed.

[0042] Of these, it is preferable that the material contains a thermoplastic non-elastic resin material such as PE, PP, or PEN.

[0043] By containing PE and PP, the wettability of the layer to be printed is likely to be improved, and the print quality can be improved.

[0044] Furthermore, by containing PEN, the gas barrier properties against oxygen, water vapor, carbon dioxide, carbon dioxide gas, etc., and the light barrier properties against ultraviolet rays and the like can be improved, making it possible to further prevent the permeation of carbon dioxide gas from inside the container.

[0045] Furthermore, by including PEN, mechanical strength can also be improved. When the functional film 24 is a single layer, the content of PEN in the functional film 24 is preferably 20% by mass or more, more preferably 50% by mass or more, and even more preferably 90% by mass or more, based on the total mass of the resin material. When the functional film 24 is a multilayer, the content of PEN in the functional film 24 is preferably 20% by mass or more, more preferably 50% by mass or more, and even more preferably 90% by mass or more, based on the total mass of the resin material contained in the layer containing PEN.

[0046] The functional film 24 may contain, as a resin material, a copolymer in which two or more monomer units constituting the above-mentioned resin are polymerized. Furthermore, the functional film 24 may be made of two or more kinds of the above-mentioned resin materials.

[0047] In addition, by mixing an inert gas (nitrogen gas, argon gas) into the molten thermoplastic resin, a foamed material with a foam cell diameter of 0.5 to 100 μm can be used and this foamed preform can be molded to improve the light blocking properties.

[0048] The functional film 24 may contain an ultraviolet absorbing agent. This ultraviolet absorbing agent may be contained in a colored layer, which will be described later, or in a printed layer.

[0049] Examples of the ultraviolet absorbing agent include a benzotriazole-based ultraviolet absorbing agent, a triazine-based ultraviolet absorbing agent, a benzophenone-based ultraviolet absorbing agent, and a benzoate-based ultraviolet absorbing agent.

[0050] When the functional film 24 is a single layer, the content of the ultraviolet absorber is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the resin material contained in the functional film 24. When the functional film 24 is a multilayer, the content of the ultraviolet absorber is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the resin material contained in the layer of the functional film 24 that contains the ultraviolet absorber.

[0051] The functional film 24 preferably has an ultraviolet ray transmittance of 5% or less, more preferably 3% or less, and further preferably 1% or less.

[0052] Ultraviolet rays refer to light rays with wavelengths of 10 nm to 400 nm. Furthermore, the transmittance of ultraviolet rays being 5% or less means that the transmittance is 5% or less over the entire ultraviolet wavelength range (10 nm to 400 nm).

[0053] The transmittance of visible light and ultraviolet light can be measured by a method conforming to JIS A5759. For example, a spectrophotometer (Shimadzu Corporation, UV3100) is used to measure in wavelengths of 10 nm to 400 nm at intervals of 0.5 nm, and the light transmittance of visible light and ultraviolet light wavelengths can be determined, respectively.

[0054] The functional film 24 may also contain a material having gas barrier properties such as oxygen barrier properties or water vapor barrier properties. In this case, the gas barrier properties of the container 10 can be improved, the content liquid can be prevented from being deteriorated by oxygen, and the content volume can be prevented from being reduced due to evaporation of water vapor.

[0055] The functional film 24 may also contain a material that has a barrier property against light such as ultraviolet rays. In this case, the light barrier property of the container 10 can be improved, and the liquid contained therein can be prevented from being deteriorated by ultraviolet rays or the like.

[0056] The functional film 24 may also contain a material with higher heat retention or cold retention (material with lower thermal conductivity) than the PET film 22. In this case, it is possible to make it difficult for the temperature of the content liquid to be transmitted to the surface of the container 10 without increasing the thickness of the container 10 itself. This improves the heat retention or cold retention of the container 10. In addition, when a user grasps the container 10, it is prevented that the container 10 becomes difficult to hold due to being too hot or too cold. Such materials include foamed polyurethane, polystyrene, PE, PP, phenolic resin, polyvinyl chloride, urea resin, silicone, polyimide, melamine resin, etc. Also, a foamed member having a foam cell diameter of 0.5 to 100 μm, which is produced by mixing an inert gas (nitrogen gas, argon gas) with a melt of a thermoplastic resin, may be used. It is preferable to mix hollow particles with a resin material containing these resins. The average particle diameter of the hollow particles is preferably 1 to 200 μm, more preferably 5 to 80 μm. The term "average particle size" means the volume average particle size, and can be measured by a known method using a particle size distribution / particle size distribution measuring device (for example, Nanotrack particle size distribution measuring device, manufactured by Nikkiso Co., Ltd.). The hollow particles may be organic hollow particles made of resin or inorganic hollow particles made of glass, but organic hollow particles are preferred because of their excellent dispersibility. Examples of resins constituting organic hollow particles include styrene resins such as crosslinked styrene-acrylic resins, (meth)acrylic resins such as acrylonitrile-acrylic resins, phenolic resins, fluorine resins, polyamide resins, polyimide resins, polycarbonate resins, and polyether resins. In addition, commercially available hollow particles such as Ropeake HP-1055, Ropeake HP-91, Ropeake OP-84J, Ropeake Ultra, Ropeake SE, and Ropeake ST (manufactured by Rohm and Haas Co., Ltd.), Nipol MH-5055 (manufactured by Zeon Corporation), SX8782, and SX866 (manufactured by JSR Corporation) can also be used.The content of the hollow particles is preferably 0.01 to 50 parts by mass, and more preferably 1 to 20 parts by mass, relative to 100 parts by mass of the resin material contained in the functional film 24 containing the hollow particles.

[0057] Furthermore, the functional film 24 may contain a material that is less slippery than the PET film 22. In this case, the user can easily grip the container 10 without changing the material of the PET film 22.

[0058] In addition to the resins that are the main components, various additives may be added to the functional film 24 within the range that does not impair its properties. Examples of additives that can be added include plasticizers, UV stabilizers, color inhibitors, matting agents, deodorants, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, release agents, antioxidants, ion exchange agents, lubricants, and color pigments.

[0059] In one embodiment, the functional film 24 includes a printed portion 17 having a colored layer and / or an area where printing is applied (printed area).

[0060] (colored layer) The colored layer may contain the above-mentioned resin material and a colorant.

[0061] The coloring agent may be brown, black, green, white, blue, or red.

[0062] Since the functional film 24 contains a colorant of a specified color, it is possible to cut (absorb or reflect) visible light in the desired wavelength range, thereby preventing the problem of the contents filled in the container 10 being denatured by visible light.

[0063] Depending on the contents, it may be necessary to cut visible light with a wavelength of 400 to 500 nm. In this case, by adding a brown colorant to the colored layer of the functional film 24 and coloring the entire film brown, it is possible to cut visible light with a wavelength of 400 to 500 nm and prevent the contents from being altered.

[0064] In this specification, visible light refers to light having a wavelength of 380 nm to 800 nm. The transmittance of visible light can be measured by a method conforming to JIS A5759. For example, a spectrophotometer (Shimadzu Corporation, UV3100) is used to measure at 0.5 nm intervals in the wavelength range of 220 to 800 nm to determine the light transmittance of the visible light wavelength.

[0065] The colorant may be a pigment or a dye, but is preferably a pigment from the viewpoint of light resistance. Among pigments, a light-reflecting pigment or a light-absorbing pigment is preferable.

[0066] Examples of light reflecting pigments include titanium white, aluminum powder, mica powder, zinc sulfide, zinc white, calcium carbonate, kaolin, and talc, while examples of light absorbing pigments include carbon black, ceramic black, and bone black.

[0067] By containing a light-reflecting colorant and / or a light-absorbing colorant, the functional film 24 can block visible light in a wider wavelength range and prevent deterioration of the content liquid filled in the container 10. Among the above-mentioned colorants, light-absorbing pigments such as black and brown are more preferable because they can significantly reduce the visible light transmittance of the functional film 24.

[0068] The colored layer may contain two or more of the above-mentioned colorants, and the functional film 24 may include two or more colored layers.

[0069] The content of the colorant in the colored layer is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 3.0 parts by mass, and even more preferably 0.5 to 2.0 parts by mass, relative to 100 parts by mass of the resin material contained in the colored layer. If the content of the colorant is within the above numerical range, the change in the resin performance of the colored layer can be suppressed as much as possible, and the color tone can be stably molded.

[0070] (Printing Department) As described above, the functional film 24 of the original film 21 has the printed portion 17 of the container body 11 .

[0071] The printing section 17 has a printed area on which a design or printing is applied.

[0072] Since the functional film 24 has the printed portion 17, it becomes possible to display images and characters on the container 10 without attaching a separate label or the like to the container body 11. For example, images and characters may be displayed on all or part of the body portion 11a of the container 10.

[0073] The printing can be carried out by a printing method such as an inkjet method, a gravure printing method, an offset printing method, or a flexographic printing method.

[0074] The printing may be applied to the functional film 24 of the container 10 after it has been blown.

[0075] Furthermore, printing may be performed on the functional film 24 before the raw film roll 21 is produced.

[0076] It is preferable to perform surface treatment such as corona treatment, low-temperature plasma treatment, and flame treatment on the portion of the functional film 24 where the printing area is to be formed. By performing such surface treatment, the wettability of the resin film and resin tube surfaces is improved, and the printing quality can be improved.

[0077] In one embodiment, it is preferable to form an anchor coat layer in advance on the functional film 24. When the anchor coat layer is provided, the adhesion of the ink to the functional film 24 is improved. Therefore, it becomes unnecessary to perform a pretreatment such as a corona treatment. Furthermore, by providing the anchor coat layer, it is possible to reduce bleeding of the print.

[0078] As described above, the functional film 24 may be composed of a single layer or multiple layers, and the resin materials forming the innermost and outermost layers of the functional film 24 may be the same or different.

[0079] Specifically, examples of functional films 24 include low-density PE+ / adhesive layer / EVOH / adhesive layer / low-density PE, PP / adhesive layer / EVOH / adhesive layer / PP, and low-density PE / adhesive layer / low-density PE+colorant (coloring layer).

[0080] At least one of these layers may contain a colorant to form a colored layer, or may be printed to form a printed layer.

[0081] Examples of adhesives that constitute the adhesive layer include polyvinyl acetate adhesives, polyacrylic ester adhesives, cyanoacrylate adhesives, ethylene copolymer adhesives, cellulose adhesives, polyester adhesives, polyamide adhesives, polyimide adhesives, amino resin adhesives, phenol resin adhesives, epoxy adhesives, polyurethane adhesives, rubber adhesives, and silicone adhesives.

[0082] (Coating layer 23) In the present embodiment, the coating layer 23 is provided on the inner surface of the PET film 22 of the original film 21 (see FIG. 4A). Alternatively, the coating layer 23 may be provided between the PET film 22 and the functional film 24 of the original film 21 (see FIG. 4B). When the coating layer 23 is provided on the inner surface of the PET film 22 (see FIG. 4A), it enhances the gas barrier properties, for example, the oxygen barrier properties, of the container 10. At the same time, the coating layer 23 provided on the inner surface of the PET film 22 exhibits water repellency and oil repellency. When the coating layer 23 is provided between the PET film 22 and the functional film 24 (see FIG. 4B), the coating layer 23 enhances the barrier properties, for example, the oxygen barrier properties, of the container 10. As described later, the coating layer 23 can also be easily peeled off from the PET film 22 after the container 10 is used. As such a coating layer 23, the following can be used.

[0083] The coating layer 23 contains a carboxyl group-containing resin and a polyvinyl alcohol-based resin. Polyvinyl alcohol resins have a high cohesive force, and therefore have a high effect of blocking oxygen and water vapor (gas barrier properties), and also have excellent stretchability. Therefore, by including a polyvinyl alcohol resin in the coating layer 23, the raw film 21 can have excellent gas barrier properties even after blow molding. In addition, the coating layer 23 can be prevented from breaking during blow molding, and the blow moldability of the raw film 21 can be improved. Since the coating layer 23 contains a carboxyl group-containing resin, the gas barrier properties can be maintained after blow molding, and such coating layer 23 is easily soluble in acid or alkali, and can be easily separated and recovered by recovering, crushing, and washing the container 10. Therefore, the original film roll 21 having the coating layer 23 and the container 10 obtained from this original film roll 21 have excellent recyclability. Furthermore, when the solvent of the coating liquid used to form the coating layer 23 is water and / or a solvent having a hydroxyl group, the carboxyl group of the carboxyl-containing resin forms a hydrogen bond with these "-OH" groups, thereby improving the viscosity of the coating liquid. This allows the thickness of the coating layer 23 to be ensured with fewer coating cycles, thereby improving the productivity of the raw film 21. Furthermore, in conventional containers 10, in order to impart gas barrier properties to the container 10, a process of reducing the pressure inside the container 10 is required, and therefore the thickness of the container 10 needs to be made at least a certain level. However, since the raw film 21 can maintain gas barrier properties even after blow molding, the process of imparting gas barrier properties to the container 10 can be omitted, and as a result, the thickness of the container 10 can be reduced, and the raw film 21 and the container 10 can be made lighter.

[0084] In the coating layer 23, the mass ratio of the carboxyl group-containing resin to the polyvinyl alcohol resin is preferably 1 / 20 or more and 10 / 1 or less, more preferably 1 / 15 or more and 5 / 1 or less, and even more preferably 1 / 10 or more and 2 / 1 or less. By setting the mass ratio to 1 / 20 or more, the recyclability of the container 10 can be further improved. By setting the above mass ratio to 10 / 1 or less, the gas barrier properties after blow molding can be further improved. The above mass ratio is a solid content ratio.

[0085] The carboxyl group-containing resin contained in the coating layer 23 of the original film 21 can be an existing carboxyl group-containing resin. The existing carboxyl group-containing resin is a general term for resins that contain a carboxyl group in the polymer structure. Examples of the carboxyl group-containing resin include homopolymers of carboxyl group-containing unsaturated monomers, copolymers of carboxyl group-containing unsaturated monomers, copolymers of carboxyl group-containing unsaturated monomers and other polymerizable monomers, and polysaccharides containing a carboxyl group in the molecule (also called "acidic polysaccharides"). These carboxyl group-containing resins can be used alone or in combination of two or more. The carboxyl group includes not only a free carboxyl group but also an acid anhydride group (specifically, a dicarboxylic anhydride group). The acid anhydride group may be partially ring-opened to form a carboxyl group. In the carboxyl group-containing resin, a part of the carboxyl group may be neutralized with an alkali.

[0086] The carboxyl group-containing unsaturated monomer is preferably an α,β-monoethylenically unsaturated carboxylic acid. Therefore, the carboxyl group-containing resin includes a homopolymer of an α,β-monoethylenically unsaturated carboxylic acid, a copolymer of two or more kinds of α,β-monoethylenically unsaturated carboxylic acids, and a copolymer of an α,β-monoethylenically unsaturated carboxylic acid and another polymerizable monomer. The other polymerizable monomer may be an ethylenically unsaturated monomer.

[0087] Examples of α,β-monoethylenically unsaturated carboxylic acids include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, etc., unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, etc., unsaturated dicarboxylic anhydrides such as maleic anhydride, itaconic anhydride, etc. These acids can be used alone or in combination of two or more kinds. From the viewpoints of blow moldability and gas barrier properties after blow molding, the α,β-monoethylenically unsaturated carboxylic acid is preferably selected from one or more of acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, and more preferably selected from one or more of acrylic acid, methacrylic acid, and maleic acid.

[0088] Other polymerizable monomers copolymerizable with α,β-monoethylenically unsaturated carboxylic acid, particularly ethylenically unsaturated monomers, include, for example, ethylene; α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene; saturated carboxylic acid vinyl esters such as vinyl acetate; acrylic acid alkyl esters such as methyl acrylate and ethyl acrylate; methacrylic acid alkyl esters such as methyl methacrylate and ethyl methacrylate; chlorine-containing vinyl monomers such as vinyl chloride and vinylidene chloride; fluorine-containing vinyl monomers such as vinyl fluoride and vinylidene fluoride; unsaturated nitriles such as acrylonitrile and methacrylonitrile; aromatic vinyl monomers such as styrene and α-methylstyrene; itaconic acid alkyl esters; etc. These monomers can be used alone or in combination of two or more.

[0089] Examples of the carboxyl group-containing polysaccharides include acidic polysaccharides having a carboxyl group in the molecule, such as alginic acid, carboxymethylcellulose, and pectin. These acidic polysaccharides can be used alone or in combination of two or more. The acidic polysaccharides can also be used in combination with a (co)polymer of an α,β-monoethylenically unsaturated carboxylic acid.

[0090] When the carboxy group-containing resin used in the present embodiment is a copolymer of α,β-monoethylenically unsaturated carboxylic acid and other ethylenically unsaturated monomers, from the viewpoints of recyclability, blow moldability, and gas barrier properties after blow molding, the composition of the copolymer is such that the composition of α,β-monoethylenically unsaturated carboxylic acid monomers is preferably 60 mol % or more, more preferably 80 mol % or more, and particularly preferably 90 mol % or more.

[0091] From the viewpoints of recyclability, blow moldability, and gas barrier properties after blow molding, the carboxyl group-containing resin is preferably a homopolymer or copolymer obtained by polymerization of only α,β-monoethylenically unsaturated carboxylic acid. When the polycarboxylic acid-based polymer is a (co)polymer consisting of only α,β-monoethylenically unsaturated carboxylic acid, the carboxyl group-containing resin is preferably a homopolymer, copolymer, or mixture of two or more thereof obtained from a carboxylic acid selected from one or more of acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, and more preferably a homopolymer, copolymer, or mixture of two or more thereof obtained from a carboxylic acid selected from one or more of acrylic acid, methacrylic acid, and maleic acid.

[0092] The carboxyl group-containing resin is preferably one or more selected from polyacrylic acid, polymethacrylic acid, and maleic acid polymer. The carboxyl group-containing resin is more preferably polyacrylic acid, which is relatively easy to obtain and has good recyclability, blow moldability, barrier properties after blow molding, and productivity of the raw film 21.

[0093] The number average molecular weight of the carboxyl group-containing resin is preferably in the range of 2,000 to 10,000,000, more preferably in the range of 5,000 to 1,000,000, and even more preferably in the range of 10,000 to 500,000, from the viewpoint of formability of the raw film 21 and the container 10. The number average molecular weight can be measured by gel permeation chromatography (GPC). In GPC measurement, the number average molecular weight of the polymer is generally measured in terms of standard polystyrene.

[0094] The content of the carboxyl group-containing resin is preferably 1% by mass or more and 80% by mass or less, more preferably 2% by mass or more and 70% by mass or less, and even more preferably 5% by mass or more and 60% by mass or less, based on all components contained in the coating layer 23. By setting the content of the carboxyl group-containing resin to 1% by mass or more, the recyclability of the container 10 can be further improved. By setting the content of the carboxyl group-containing resin to 80% by mass or less, the gas barrier property after blow molding can be further improved.

[0095] The polyvinyl alcohol resin (also referred to as "PVA resin") contained in the coating layer 23 of the raw film 21 is a resin containing an alcoholic hydroxyl group in the polymer structure. The PVA resin is usually obtained by saponifying a vinyl ester polymer.

[0096] Vinyl ester polymers are usually obtained by polymerizing vinyl ester monomers as polymerization components. Examples of vinyl ester monomers include fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caprylate, vinyl versatate, and vinyl monochloroacetate, and aromatic carboxylic acid vinyl esters such as vinyl arene carboxylates (e.g., C7-12 arene carboxylic acid vinyl esters) such as vinyl benzoate. These monomers can be used alone or in combination of two or more.

[0097] The vinyl ester polymer may have a unit derived from another polymerizable monomer (monomer copolymerizable with vinyl ester). Examples of other polymerizable monomers include ethylene; α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene; methacrylic acid alkyl esters such as methyl methacrylate and ethyl methacrylate; chlorine-containing vinyl monomers such as vinyl chloride and vinylidene chloride; fluorine-containing vinyl monomers such as vinyl fluoride and vinylidene fluoride; unsaturated nitriles such as acrylonitrile and methacrylonitrile; aromatic vinyl monomers such as styrene and α-methylstyrene; itaconic acid alkyl esters; and the like. These monomers may be used alone or in combination of two or more.

[0098] The PVA-based resin may be one in which a part of the vinyl alcohol units has been modified by a reaction such as acetalization, etherification, acetoacetylation, or cationization.

[0099] From the viewpoint of formability of the raw film 21 and the container 10, the polymerization degree of the PVA-based resin is preferably 1000 or more and 4000 or less, more preferably 1500 or more and 3500 or less, and even more preferably 2000 or more and 3000 or less. The average degree of polymerization of the PVA-based resin can be measured in accordance with JIS K 6726:1994.

[0100] From the viewpoints of excellent solubility in a solvent and excellent storage stability of the composition, the saponification degree of the PVA-based resin is preferably 70 mol% or more and 99.9 mol% or less, more preferably 90 mol% or more and 99.5 mol% or less, and even more preferably 95 mol% or more and 99.5 mol% or less. The degree of saponification of the PVA-based resin can be measured in accordance with JIS K 6726:1994.

[0101] When the PVA-based resin is dissolved in pure water to a concentration of 4 mass %, the aqueous solution viscosity is preferably 3 mPa·s or more and 70 mPa·s or less, more preferably 50 mPa·s or more and 68 mPa·s or less, and even more preferably 54 mPa·s or more and 66 mPa·s or less. The viscosity of the coating liquid can be measured at a temperature of 20° C. in accordance with JIS Z 8803:2011.

[0102] The PVA-based resins can be used alone or in combination of two or more.

[0103] The content of the polyvinyl alcohol-based resin is preferably 20% by mass or more and 99% by mass or less, more preferably 30% by mass or more and 98% by mass or less, and even more preferably 40% by mass or more and 95% by mass or less, based on all components contained in the coating layer 23. By setting the content of the polyvinyl alcohol-based resin to 20% by mass or more, the gas barrier property after blow molding can be further improved. By setting the content of the polyvinyl alcohol-based resin to 99% by mass or less, the recyclability of the container 10 can be further improved.

[0104] The coating layer 23 of the raw film 21 may contain additives to the extent that the characteristics of the present invention are not impaired. Examples of additives include oxygen absorbers, plasticizers, UV stabilizers, antioxidants, coloring inhibitors, matting agents, deodorants, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, release agents, antioxidants, ion exchange agents, and colorants. These additives can be used alone or in combination of two or more.

[0105] The coating layer 23 of the raw film 21 may be a single layer or a multi-layer structure having two or more layers. When the coating layer 23 is a multi-layer structure, each layer may have the same composition or different compositions.

[0106] The thickness of the coating layer 23 of the raw film 21 means the portion where the thickness is the thinnest. When the coating layer 23 has multiple layers, the thickness of the coating layer 23 is the total thickness of all the layers.

[0107] In this embodiment, the thickness of the PET film 22 of the original film 21 is 200 μm or more and 500 μm or less, the thickness of the functional film 24 is 30 μm or more and 300 μm or less, and the thickness of the coating layer 23 is 0.1 μm or more and 200 μm or less.

[0108] Next, the operation of this embodiment having the above-mentioned configuration, that is, the blow molding method, will be described with reference to FIGS. 1A to 2C.

[0109] First, a film roll 21 is prepared as shown in Fig. 2A. In this case, the film roll 21 has an uncolored and unprinted PET film 22, a coating layer 23 provided on the inner surface side of the PET film 22, and a functional film 24 provided on the outer surface side of the PET film 22, as shown in Fig. 4A.

[0110] Thus, the original film 21 has the PET film 22, the coating layer 23, and the functional film 24, but in this embodiment, the PET film 22 and the functional film 24 may be prepared first, and then the PET film 22 and the functional film 24 may be laminated together. After that, the coating layer 23 is formed on the PET film 22 by a normal coating method.

[0111] The functional film 24 of the original film roll 21 has a printed portion 17. The printed portion 17 is provided on this functional film 24 before it is laminated with the PET film 22, but the printed portion 17 may be provided on the functional film 24 after it is laminated with the PET film 22. Alternatively, the original film roll 21 may have the PET film 22, the functional film 24, and a coating layer 23 provided between the PET film 22 and the functional film 24 (see FIG. 4B).

[0112] Next, as shown in FIG. 2B, the original film 21 is heated and then folded in half to form a folded portion 21a.

[0113] Thereafter, the film roll 21 folded in half is placed in a blow molding die 30 (see FIG. 2C).

[0114] The blow molding die 30 has two split parts 30A and 30B, and after the two split parts 30A and 30B are pulled apart from each other, the folded film web 21 is inserted between the parts 30A and 30B. After the film web 21 is inserted between the parts 30A and 30B, the parts 30A and 30B are joined together again.

[0115] As shown in FIG. 1A, a blow molding die 30 consisting of parts 30A and 30B has a plurality of cavities 31 therein, for example, five cavities 31, and an opening 32 provided at the top of each cavity 31.

[0116] In the blow molding die 30 shown in FIG. 1A, the folded portion 21a of the folded film raw material 21 is located on the bottom 31a side of the cavity 31 of the blow molding die 30, and forms the bottom edge of the peripheral portion 19 of the container .

[0117] The film roll 21 thus folded in two is placed in a blow molding die 30 and is sandwiched between two portions 30A and 30B.

[0118] Next, as shown in FIG. 1B, air is supplied into the raw film 21 through the opening 32 of the blow molding die 30.

[0119] When air is supplied into the film web 21 , the film web 21 expands within the blow molding die 30 , and the film web 21 reaches the inner surface of the cavity 31 .

[0120] In this manner, the raw film 21 is expanded within the blow molding die 30 , whereby the container 10 can be obtained by the blow molding die 30 .

[0121] At this time, the container 10 is formed by a cavity 31. The container 10 has a container body 11 having a body portion 11a, a bottom portion 11b, and a shoulder portion 11c, and an opening portion 12 provided at an upper portion of the container body 11 and formed by an opening 32.

[0122] Next, as shown in Fig. 1C, the container 10 formed by the blow molding die 30 is removed from the blow molding die 30. As shown in Fig. 1C, five containers 10 are produced by the blow molding die 30, and the containers 10 are connected to each other via the peripheral portions 19a to form a connected bottle 10A.

[0123] Next, the connected bottle 10A is sent to a filling device (not shown), and the content liquid 20 is filled into each container 10 through the opening 12.

[0124] Thereafter, as shown in Fig. 1D, the connected bottle 10A in which each container 10 is filled with the content liquid is sent to a sealing device (not shown). Next, in this sealing device, the insertion portion 15a of the cap 15 is inserted into the opening 12 of each container 10 of the connected bottle 10A, and the insertion portion 15a of the cap 15 is heat-sealed to the inner surface of the opening 12 by the sealing device. In this manner, the opening 12 of each container 10 is sealed by the cap 15. When in use, the opening 12 can be opened by cutting the opening 12 by rotating the cap 15 relative to the opening 12.

[0125] In this embodiment, an example is shown in which a cap 15 is inserted into the opening 12 of each container 10 of the connected bottle 10A and this opening 12 is sealed with the cap 15 (see Figure 1D), but this is not limited to the above. As shown in Figure 1E, the opening 12 may be sealed by directly heat-sealing the opening 12 without inserting a cap 15 into the opening 12 of each container 10 of the connected bottle 10A, and in this case, a heat-sealed portion 25A is formed at the opening 12.

[0126] In this case, a slit 12a may be provided immediately below the heat-sealed portion 25A of the opening 12, and the opening 12 may be opened by cutting from this slit 12a (see FIG. 1F).

[0127] Alternatively, instead of providing a cap 15 at the opening 12 of each container 10 of the connected bottle 10A, a straw (not shown) may be provided at the opening 12.

[0128] In this way, as shown in Fig. 3A, a connected bottle 10A is obtained, which includes five containers 10 and is configured by connecting each container 10 to each other via the peripheral edge portion 19a. In this case, the printed portion 17 provided on the functional film 24 of the original film roll 21 is exposed on the surface of the barrel portion 11a of the container body 11 of each container 10.

[0129] Next, the entire connected bottle 10A is covered with shrink wrap 25. This allows the connected bottles 10A to be covered collectively with shrink wrap 25, which makes packaging and transportation easier.

[0130] For use, the shrink wrap 25 is removed from the connected bottle 10A, and the peripheral portion 19a is broken to remove the individual containers 10.

[0131] Next, the cap 15 is rotated to cut and open the opening 12 (see FIG. 1D), or the opening 12 is cut and opened from the notch 12a of the opening 12 (see FIGS. 1E and 1F).

[0132] The liquid content within the container body 11 can then be drunk from the opening 12.

[0133] When the container 10 is empty, the container 10 is discarded. In this case, the cap 15 is removed from the container 10, and the original film roll 21 of the container 10 is unfolded.

[0134] Thereafter, the unfolded original film roll 21 is separated into the PET film 22 and the functional film 24 provided on the outer surface of the PET film 22. The original film roll 21 may have a coating layer 23 on the inner surface of the PET film 22, in which case the coating layer 23 is peeled off from the PET film 22. When the coating layer 23 contains a carboxyl group-containing resin and a polyvinyl alcohol-based resin, the coating layer 23 is easily soluble in acid or alkali. Therefore, the coating layer 23 can be easily and simply removed from the PET film 22.

[0135] Next, the PET film 22, the functional film 24, and the coating layer 23 are treated separately and independently.

[0136] Among the PET film 22, the functional film 24, and the coating layer 23, the PET film 22 in particular is an uncolored and unprinted film, so it can be regenerated as recycled PET by processing the PET film 22. In this way, using the uncolored and unprinted PET film 22, a highly accurate recycled PET can be obtained.

[0137] As described above, according to this embodiment, the original film roll 21 has the uncolored and unprinted PET film 22, the functional film 24 removably provided on the PET film 22, and the coating layer 23 removably provided on the PET film 22. Therefore, after discarding the used container 10, the original film roll 21 of the container 10 can be unfolded, and the PET film 22, the functional film 24, and the coating layer 23 can be peeled off from each other and then separated for processing. In particular, since the PET film 22 is an uncolored and unprinted film, it is possible to regenerate highly accurate recycled PET by processing the PET film 22 in an original way, and use this recycled PET as a material to manufacture new products.

[0138] According to this embodiment, a plurality of, for example, five, containers 10 are connected to each other via the periphery 19a to obtain a connected bottle 10A. The connected bottles 10A are then covered as a whole with shrink wrap 25, which makes it easy to package or transport the connected bottles 10A. Furthermore, by printing on the shrink wrap 25 itself, it becomes unnecessary to print on the original film roll 21. This further improves the recyclability of the original film roll 21.

[0139] Furthermore, the raw material sheet constituting the container 10 has a functional film 24. In this case, the functional film 24 can have a display function by providing a colored layer or a printed portion 17 on the functional film 24. Furthermore, by providing the functional film 24 with gas barrier properties, the preservation ability of the content liquid 20 in the container 10 can be improved.

[0140] Furthermore, if the functional film 24 has a heat insulating function, the container 10 can be easily handled, and if the functional film 24 has an ultraviolet absorbing function, the liquid content in the container 10 can be protected from ultraviolet rays.

[0141] The heated film roll 21 is placed in two split portions 30A and 30B of a blow molding die 30 having a plurality of cavities, for example, five cavities 31. Next, air is supplied into the film roll 21, so that a connected bottle 10A having five containers 10 can be easily and reliably produced by blow molding using the blow molding die 30. [Explanation of symbols]

[0142] 10 containers 10A Connecting Bottle 11 Container body 11a Torso 11b Bottom 11c Shoulder 12 Opening 12a Cut 15 Cap 17 Printing Department 19 Periphery 19a Periphery 20 Content liquid 21 Film roll 22 PET film 23 Coating layer 24 Functional Films 25 Shrink Wrap 25A Heat seal section 30 Blow molding mold 30A,30B part 31 Cavity 32 Aperture

Claims

1. preparing a film roll; A step of folding the film roll in half and placing it in a blow molding die; and supplying air into the film roll placed in the blow molding die to form a container having an opening and a container body. The blow molding method, wherein the film stock comprises an uncolored and unprinted PET film.

2. The blow molding method according to claim 1 , wherein the raw film further comprises a functional film releasably provided on an outer surface of the PET film.

3. The blow molding method according to claim 1 or 2, further comprising the step of filling the container with a content through an opening of the container.

4. 4. The blow molding method of claim 3, further comprising the step of heat sealing said opening of said container closed.

5. The blow molding method according to claim 2, wherein the functional film of the raw film is a printed PE film or PP film.

6. The blow molding method according to claim 2 , wherein the raw film further comprises a coating layer provided on an inner surface of the PET film or between the PET film and the functional film.

7. 3. The blow molding method according to claim 1, wherein a plurality of the containers are provided, and adjacent container bodies are connected to each other.

8. 2. The blow molding method of claim 1, further comprising providing a shrink wrap over an exterior surface of the container.

9. 8. The blow molding method of claim 7, further comprising providing a shrink wrap around the connected containers.

10. 3. The blow molding method of claim 2, further comprising the step of processing the PET film and the functional film separately after peeling the functional film from the PET film of the container.

11. A container having an opening and a container body, A container comprising an uncolored and unprinted PET film and a functional film releasably provided on the outer surface of the PET film.

12. The container according to claim 11, wherein the functional film is a PE film or a PP film.

13. The container of claim 11 , further comprising a barrier coating layer provided on the inner surface of the PET film or between the PET film and the functional film.

14. The container according to claim 11 , wherein a plurality of the containers are provided, and adjacent container bodies are connected to each other.

15. 14. The container of any one of claims 11 to 13, further comprising a shrink wrap covering an exterior surface of the container.

16. 15. The container of claim 14, further comprising a shrink wrap covering the joined containers together.

Images