Molded article manufacturing method and molded article

Abstract

Provided is a molded article manufacturing method capable of obtaining a molded article having excellent extensibility by recovering recycled plastic from a laminate including a plastic film layer and a functional layer. This molded article manufacturing method comprises: an immersion step for immersing, in an alkali-containing separation liquid, a laminate including a polyolefin film layer and a functional layer; a wet crushing step for wet-crushing the laminate after the immersion step in the presence of water to obtain film pieces of a recycled polyolefin resin; and a molding step for performing molding using the film pieces to obtain a molded article, wherein the manufactured molded article has a content of the recycled polyolefin resin of at least 50 mass%, and a ratio (P040 / P110) of the peak intensity P040 of the (040) plane to the peak intensity P110 of the (110) plane of at most 1.00.

Description

Molded product manufacturing method and molded product

[0001] The present invention relates to a method for manufacturing a molded product, and to a molded product.

[0002] Currently, the amount of waste plastic that is separated and collected (recycling rate) is 9% of all plastic produced worldwide. Of the 91% of waste plastic that is not separated and collected, 12% is incinerated, and 79% is landfilled or leaks into the environment (Non-Patent Document 1). One of the reasons for this persistently low recycling rate is the difficulty of implementing a separate collection system.

[0003] Specifically, in order to recycle plastics, it is necessary to separate and collect waste plastics that contain different types of plastic materials, such as polyethylene (PE) and polypropylene (PP), into individual materials. However, in many plastic products, including laminated films, different types of plastic materials are bonded together, making it difficult to separate and collect each material. Therefore, there is a strong demand for the development of a recycling system that can easily separate and collect waste plastics.

[0004] In addition, from a cost perspective, it is difficult to return recycled plastic products to the same product as before recycling. Furthermore, plastic products generally deteriorate every time they are recycled. Therefore, recycled plastic products inevitably lose quality.

[0005] In this regard, one reason for the decline in quality of recycled plastics is the presence of ink or pigments as impurities in the plastic. In particular, many plastic products have printed surfaces, making them difficult to decolorize during the recycling process. Furthermore, plastic films that make up plastic products typically have various functional layers, such as hard coat layers, adhesive layers, and removable primer layers, in addition to ink layers (printed layers). However, components derived from these functional layers can also cause unintended coloration.

[0006] As a result, recycled plastic products are often discolored. Not only does this significantly reduce the commercial value of such recycled plastic products, but the impurities can also cause deterioration in physical properties such as tensile strength. Therefore, a method for producing high-quality recycled plastic products is needed.

[0007] For example, Patent Document 1 proposes a method for recycling multilayer film waste containing a plastic layer and an aluminum layer. Specifically, Patent Document 1 discloses a recycling method in which the aluminum layer of a pulverized multilayer film is dissolved with an alkali, the remaining pulverized material is separated based on the difference in specific gravity, and then the remaining pulverized material is selectively heated and dissolved in an organic solvent, thereby separating valuable components.

[0008] Furthermore, Patent Document 2 proposes a method for removing ink from a printed plastic film. Specifically, Patent Document 2 discloses a method in which the printed plastic film is treated with a plunger, then crushed in a crusher, the ink on the film is removed in a predetermined washing system, and the treated plastic film is then rinsed and dried.

[0009] Science Advances 19 Jul 2017:Vol. 3, no. 7, e1700782

[0010] JP 2006-205160 A JP 2015-520684 A

[0011] However, both of the methods described in Patent Documents 1 and 2 involve many steps, are lengthy, and are complicated. Furthermore, the method described in Patent Document 1 is intended only for removing the aluminum layer, and the method described in Patent Document 2 is intended only for removing the ink. Therefore, it is difficult to remove various functional layers using these methods.

[0012] Furthermore, Patent Documents 1 and 2 mainly focus only on removing layers formed on plastic films, and do not consider improving the physical properties, such as the extensibility, of recycled plastic products (molded products).

[0013] Therefore, an object of the present invention is to provide a method for producing a molded article that can recover recycled plastic from a laminate including a plastic film layer and a functional layer, and can produce a molded article with excellent stretchability. Another object of the present invention is to provide a molded article with excellent stretchability that can be produced by the above-mentioned production method.

[0014] The present inventors have conducted extensive research and found that the above-mentioned problems can be solved by using a laminate including a polyolefin film layer and a functional layer as a raw material and performing a predetermined process, thereby completing the present invention.

[0015] [1] A method for producing a molded product, comprising recovering recycled polyolefin resin from a laminate comprising a polyolefin film layer and a functional layer, and producing a molded product using the recycled polyolefin resin, the method comprising: an immersion step of immersing the laminate in a release liquid containing an alkali; a wet-crushing step of wet-crushing the laminate after the immersion step in the presence of water to obtain film pieces of recycled polyolefin resin; and a molding step of molding using the film pieces to obtain a molded product, wherein the produced molded product has a recycled polyolefin resin content of 50% by mass or more, and has a peak intensity P of the (110) plane in X-ray diffraction when molded to a thickness of 4 mm. １１０ The peak intensity P of the (040) plane ０４０ The ratio (P ０４０ / P １１０ ) is 1.00 or less.

[0016] [2] The method according to [1], wherein the wet crushing is carried out under the action of shaking or beating.

[0017] [3] The method according to [1] or [2], wherein the molding step includes melt-kneading and extruding the film pieces or a composition containing the film pieces.

[0018] [4] The method according to any one of [1] to [3], further comprising a rinsing step of washing the film pieces with a rinsing liquid after the wet crushing step.

[0019] [5] The method according to [4], wherein the rinse solution contains a water-soluble solvent.

[0020] [6] A molded article containing a polyolefin resin, wherein in X-ray diffraction when molded to a thickness of 4 mm, the peak intensity P of the (110) plane is １１０ The peak intensity P of the (040) plane ０４０ The ratio (P ０４０ / P １１０ ) is 1.00 or less.

[0021] According to the present invention, a method for producing a molded article can be provided that recovers recycled plastic from a laminate including a plastic film layer and a functional layer, and that produces a molded article having excellent stretchability. Furthermore, according to the present invention, a molded article having excellent stretchability that can be produced by the above-mentioned production method can be provided.

[0022] The present invention will be described in detail below by way of example based on embodiments thereof.

[0023] <Method for manufacturing a molded product> A method for manufacturing a molded product according to one embodiment of the present invention (hereinafter sometimes referred to as the "method of the present embodiment") is a method for manufacturing a molded product, which involves recovering recycled polyolefin resin from a laminate comprising a polyolefin film layer and a functional layer, and using the recycled polyolefin resin to manufacture a molded product. The method of the present embodiment is characterized by including: an immersion step in which the laminate is immersed in a release liquid containing an alkali; a wet-crushing step in which the laminate after the immersion step is wet-crushed in the presence of water to obtain film pieces of recycled polyolefin resin; and a molding step in which the film pieces are molded to obtain a molded product.

[0024] Furthermore, in the method of the present embodiment, the molded product to be produced has a recycled polyolefin resin content of 50% by mass or more, and when molded to a thickness of 4 mm, the peak intensity P １１０The peak intensity P of the (040) plane ０４０ The ratio (P ０４０ / P １１０ ) is 1.00 or less.

[0025] As a result of intensive research by the present inventors, it has been found that by using a laminate having a polyolefin film layer and a functional layer as the processing target, and by carrying out a predetermined immersion process and wet crushing process, as in the method of this embodiment, it is possible to obtain recycled plastic (film pieces of recycled polyolefin resin) suitable as a molding material. Furthermore, as a result of intensive research by the present inventors, it has been found that by carrying out a molding process using such recycled plastic film pieces, it is possible to obtain molded products with excellent elongation. Furthermore, molded products with excellent elongation obtained in this way typically have a specific crystalline structure, i.e., the above-mentioned peak intensity ratio P ０４０ / P １１０ It has also been found that the peak intensity ratio, and hence the improvement in extensibility, is presumably due to a specific change in the crystalline structure of the polyolefin film layer caused by appropriately carrying out the specified wet crushing step and molding step.

[0026] Furthermore, in the method of this embodiment, the processing target is not limited to a printed layer, but can also be a laminate in which various functional layers described below are provided on a polyolefin film layer, and the desired molded product can be produced.

[0027] (Laminate as Treatment Target) In the method of the present embodiment, a laminate including at least a polyolefin film layer and a functional layer is used as a treatment target.

[0028] The laminate used in this embodiment is, for example, a polyolefin film (a type of plastic film) in a non-roll form. Alternatively, the laminate may be cut out from a polyolefin film in a roll form.

[0029] The laminate used in this embodiment may be, for example, a waste polyolefin film (one of the so-called waste plastic films). The laminate is not particularly limited, and may be a polyolefin film generally distributed as a packaging material for food packaging or daily necessities, or a film having various types of discarded polyolefin film layers. The laminate may be used alone or in combination of two or more types.

[0030] The laminate used in this embodiment may include only one polyolefin film layer, or may include two or more polyolefin film layers. When the laminate includes two or more polyolefin film layers, the polyolefins constituting these polyolefin film layers may be the same or different from each other.

[0031] The laminate used in this embodiment may include only one functional layer, or may include two or more functional layers. When the laminate includes two or more functional layers, these functional layers may be the same as or different from each other.

[0032] The laminate used in this embodiment may be, for example, a laminate having a functional layer on the outermost surface, or a laminate in which a functional layer is provided between multiple polyolefin film layers.

[0033] [Polyolefin Film Layer] As described above, the laminate used in this embodiment includes a polyolefin film layer. Note that the polyolefin film layer refers to a layered member containing polyolefin as the main constituent resin.

[0034] The polyolefin is not particularly limited, and examples thereof include polyethylenes such as low-density polyethylene, high-density polyethylene, and linear low-density polyethylene; polypropylenes such as OPP (biaxially oriented polypropylene) and CPP (non-oriented polypropylene); propylene-ethylene copolymers; ethylene-butene-propylene copolymers; etc. In particular, from the viewpoints of versatility and ease of recovery of the finally obtained molded product, the laminate used in this embodiment preferably includes a polyolefin film layer (i.e., a polypropylene film layer) containing polypropylene such as OPP or CPP as the main constituent resin.

[0035] The thickness of the polyolefin film layer is not particularly limited, but is preferably, for example, 5 μm or more, or 10 μm or more, and is preferably, for example, 500 μm or less, 200 μm or less, 100 μm or less, or 50 μm or less.

[0036] The polyolefin film layer is preferably in contact with the functional layer in the laminate, and is preferably located on the outermost surface of the laminate.

[0037] [Other Resin Film Layers] The laminate used in this embodiment may or may not include other resin film layers other than the polyolefin film layer. Examples of such other resin film layers include polyester-based films made of polyethylene terephthalate (PET), polybutylene terephthalate, etc.; polyamide-based films made of nylon 6, nylon 6,6, metaxylene adipamide (N-MXD6), etc.; biodegradable films made of polylactic acid, etc.; polyacrylonitrile-based films; poly(meth)acrylic-based films; polystyrene-based films; polycarbonate-based films; saponified ethylene-vinyl acetate copolymer (EVOH)-based films; polyvinyl alcohol-based films; triacetyl cellulose-based films; etc. However, from the viewpoint of the efficiency of collecting recycled plastics, it is preferable that the laminate used in this embodiment does not include other resin film layers other than the polyolefin film layer.

[0038] [Functional Layer] As described above, the laminate used in this embodiment includes a functional layer. The functional layer is not particularly limited, and examples thereof include a printing layer (also referred to as an ink layer), an adhesive layer, a removable primer layer, and a functional coating layer. The laminate may include one type of these functional layers alone, or two or more types in combination.

[0039] The functional layer (printing layer, adhesive layer, removable primer layer, functional coating layer, etc.) can contain a resin having an acidic group or a low molecular weight compound having an acidic group. The functional layer can also contain a resin not having an acidic group in addition to the resin having an acidic group or the low molecular weight compound having an acidic group.

[0040] Examples of resins having an acidic group include rosin-modified maleic acid resins, rosin-modified fumaric acid resins, and polymer resins obtained by copolymerizing polymerizable monomers having an acidic group. Examples of polymerizable monomers having an acidic group include polymerizable monomers having a carboxyl group such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, cinnamic acid, and acid anhydrides thereof, polymerizable monomers having a sulfonic acid group such as sulfonated styrene, and polymerizable monomers having a sulfonamide group such as vinylbenzenesulfonamide. Specific examples of the polymer resin include (meth)acrylic resins, styrene-(meth)acrylic resins, styrene-maleic acid (anhydride) resins, and terpene-maleic acid (anhydride) resins.

[0041] Examples of low molecular weight compounds having an acidic group include saturated fatty acids, unsaturated fatty acids, hydroxy acids, aromatic carboxylic acids, dicarboxylic acids, tricarboxylic acids, oxocarboxylic acids, carboxylic acid derivatives, and acid anhydrides.

[0042] Saturated fatty acids include lauric acid, myristic acid, palmitic acid, margaric acid, and stearic acid. Unsaturated fatty acids include oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and sorbic acid. Hydroxy acids include lactic acid, malic acid, and citric acid. Aromatic carboxylic acids include benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, gallic acid, mellitic acid, and cinnamic acid. Dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, and maleic acid. Tricarboxylic acids include aconitic acid. Oxocarboxylic acids include pyruvic acid and oxaloacetic acid. Carboxylic acid derivatives include amino acids and nitrocarboxylic acids. Acid anhydrides include trimellitic anhydride and pyromellitic anhydride.

[0043] -Printed Layer- The laminate used in this embodiment can include a printed layer as a functional layer. The printed layer is typically a layer containing ink. The printed layer may be a layer on which any design, pattern, letter, symbol, etc. is displayed for the purpose of providing decoration or aesthetic appeal, or for displaying the contents, expiration date, manufacturer or seller, etc. Alternatively, the printed layer may be a layer on which no design, pattern, letter, symbol, etc. is displayed (i.e., a layer with no gaps, a solid layer).

[0044] The printed layer is formed by printing using, for example, a gravure printing machine, a flexographic printing machine, an offset printing machine, an inkjet printing machine, etc. That is, the ink used to form the printed layer may be an ink for gravure printing (gravure ink), an ink for flexographic printing (flexo ink), an ink for offset printing (offset ink), or an ink for inkjet printing (inkjet ink).

[0045] The ink may be, for example, an organic solvent-based printing ink, a water-based ink, or an active energy ray-curable ink. The ink contained in the printed layer may be a single type or a combination of two or more types. Furthermore, the printed layer may be a monochromatic printed layer or a multicolored printed layer.

[0046] The print layer may be located on the outermost surface of the laminate, or may be sandwiched between other layers.

[0047] -Adhesive Layer- The laminate used in this embodiment may include an adhesive layer as a functional layer. The adhesive constituting the adhesive layer may be any adhesive that can be used in a general-purpose lamination method. Examples of lamination methods include dry lamination or wet lamination using a solvent-based lamination adhesive, and non-solvent lamination using a solvent-free lamination adhesive.

[0048] Examples of the adhesive include vinyl resins, (meth)acrylic resins, polyamide resins, polyester resins, polyether resins, polyurethane resins, epoxy resins, rubber resins, etc. Such adhesives may be one-component or two-component, and may be curable or non-curable.

[0049] The adhesive layer is usually formed by applying an adhesive layer composition (solution) to the surface to be formed and drying it.

[0050] The adhesive layer is preferably sandwiched between other layers (polyolefin film layers; functional layers other than the adhesive layer; etc.) in the laminate.

[0051] -Removable Primer Layer- The laminate used in this embodiment can have a removable primer layer as a functional layer. In this case, recyclability can be improved and the quality of the recycled plastic can be improved. The removable primer layer can be easily removed from other layers by treatment with a solution (removal liquid) containing an alkali.

[0052] The removable primer layer in the laminate is preferably in contact with the polyolefin film layer. The removable primer layer in the laminate is preferably bonded to and sandwiched between the polyolefin film layer and a functional layer other than the removable primer layer (e.g., a printing layer, an adhesive layer, a functional coating layer, etc.). This can further improve recyclability and the quality of the recycled plastic.

[0053] The removable primer layer is usually formed by applying a composition (solution) for a removable primer layer to a surface to be formed, and drying it.

[0054] Furthermore, the removable primer layer (and the removable primer layer composition) may contain a resin that has film-forming properties at room temperature. Examples of resins that have film-forming properties at room temperature include polyester; polyvinyl chloride; copolymers of vinyl chloride and other unsaturated double bond-containing monomers; (meth)acrylic acid ester homopolymers; copolymers of (meth)acrylic acid esters and other unsaturated double bond-containing monomers; polystyrene; copolymers of styrene monomers and other unsaturated double bond-containing monomers; ketone-formaldehyde condensates or hydrogenated products thereof; polyfunctional epoxy resins; polyvinyl acetal; urethane resins; and the like. Examples of polyfunctional epoxy resins include bisphenol A novolac epoxy resins, bisphenol F novolac epoxy resins, bisphenol S novolac epoxy resins, biphenyl epoxy resins, and naphthalene epoxy resins. These resins that have film-forming properties at room temperature may be used alone or in combination of two or more.

[0055] In one embodiment, the removable primer layer preferably contains a urethane resin. Such a removable primer layer can be formed using, for example, a composition for a removable primer layer containing a urethane resin and an aqueous medium.

[0056] The urethane resin is a general term for a polymer compound having a urethane bond (—NHCOO—). The urethane resin can be obtained, for example, by reacting an aromatic polyester polyol with a polyisocyanate and, if necessary, a chain extender or the like.

[0057] In another embodiment, the removable primer layer preferably contains polyvinyl alcohol. Such a removable primer layer can be formed using, for example, a composition for a removable primer layer containing polyvinyl alcohol and an aqueous medium.

[0058] Polyvinyl alcohol is a colorless powder obtained by saponifying polyvinyl acetate. It is also a water-soluble thermoplastic resin and is the raw material for the synthetic fiber vinylon.

[0059] Examples of the aqueous medium include water and organic solvents miscible with water. The aqueous medium may be used alone or in combination of two or more. Examples of the organic solvent miscible with water include alcohols such as methanol, ethanol, n-propanol, and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol, and propylene glycol; alkyl ethers of polyalkylene glycols; and N-methyl-2-pyrrolidone.

[0060] -Functional Coating Layer- The laminate used in this embodiment can be provided with a functional coating layer as a functional layer. The functional coating layer can be provided on the laminate for purposes such as hard coating, silicone-based release, IR cut, waterproof and moisture-proof, antibacterial, UV cut, heat dissipation, photocatalysis, weather resistance, anti-fogging, fingerprint and stain resistance, self-repair, and water and oil repellency. Specific examples of the functional coating layer include a hard coating layer, an adhesive layer, a release layer, a decorative layer, a light-shielding layer, an ultraviolet-shielding layer, an antistatic layer, a refractive index adjustment layer, and an oligomer sealing layer. These functional coating layers may be colorless or colored.

[0061] The functional coating layer can be formed by applying various coating agents to the surface to be formed, such as surface modifiers such as hard coating agents, self-healing coating agents, anti-fingerprint and anti-fouling coating agents, anti-fog coating agents, silicone-based release agents, non-silicone-based release agents, waterproof and moisture-proof coating agents, water-repellent and oil-repellent coating agents, photocatalytic coating agents, weather-resistant coating agents, IR-cut coating agents, optical pressure-sensitive adhesives, polyimide varnishes, liquid crystal alignment film materials, electromagnetic wave shielding coating agents, fine wiring pastes, antistatic coating agents, high refractive index coating agents, optical lens coating agents, etc. The thickness of these functional coating layers is preferably 0.1 μm or more and 100 μm or less, more preferably 0.1 μm or more and 10 μm or less, and even more preferably 1 μm or more and 5 μm or less.

[0062] The functional coating layer may be a layer (metal layer) formed of a metal material. The metal layer may be a metal foil, or a metal vapor deposition layer formed by vapor deposition of a metal or metal oxide. Examples of metal foils include foils of metals with excellent ductility, such as gold, silver, copper, zinc, iron, lead, tin, and alloys thereof, steel, stainless steel, and aluminum. Examples of metal vapor deposition layers include layers containing aluminum, aluminum oxide, silica, zinc oxide, etc.

[0063] The functional coating layer may be a single layer, or may be a multilayer consisting of the same or different functional coating layers. For example, the functional coating layer may be a multilayer consisting of a layer formed using the various coating agents and the metal vapor deposition layer. In this case, the layer formed using the various coating agents may be provided on the laminate via a metal vapor deposition layer in contact with the polyolefin film layer.

[0064] Next, each step constituting the method of this embodiment will be described.

[0065] (Pretreatment Step) In the method of this embodiment, there is no particular limitation, and a pretreatment step of crushing the above-mentioned laminate may be performed prior to the immersion step. By performing such a pretreatment step, the processing efficiency of each subsequent step is improved, and the recovery of recycled plastic from the laminate (obtaining film pieces of recycled polyolefin resin) can be performed more efficiently. The method of crushing the laminate is not particularly limited, and known methods can be used. Furthermore, the crushing of the laminate can be performed in an air atmosphere in the absence of liquids such as solvents, and in this case, a known dry crusher can be suitably used.

[0066] When the pretreatment step is carried out, the laminate can be crushed so that the short and long sides are preferably 1 mm to 30 mm, more preferably 1 mm to 20 mm.

[0067] (Immersion Step) In the method of the present embodiment, the immersion step involves immersing the above-described laminate in a release solution containing an alkali, thereby causing the laminate to swell.

[0068] [Removal Solution] Examples of the alkali in the removal solution include sodium hydroxide, lithium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogencarbonate, ammonium, etc. Among these, sodium hydroxide or potassium hydroxide is preferred as the alkali, and sodium hydroxide is more preferred.

[0069] The concentration of the alkali in the desorption liquid is, for example, preferably 0.1% by mass to 10% by mass, more preferably 0.1% by mass to 5% by mass, as a proportion of the total amount of the desorption liquid.

[0070] The pH of the desorption liquid is preferably 10 or more, more preferably 11 or more, and even more preferably 12 or more.

[0071] The desorption liquid may contain water, which can improve operational stability and environmental stability.

[0072] The release liquid may contain a surfactant. The surfactant is not particularly limited, and known surfactants can be used. Examples of the surfactant include anionic surfactants, nonionic surfactants, amphoteric surfactants, and cationic surfactants. One type of surfactant may be used alone, or two or more types may be used in combination. When a surfactant is used, the concentration of the surfactant in the release liquid is preferably 0.01% by mass to 5% by mass, and more preferably 2% by mass or less, in terms of the proportion of the total release liquid.

[0073] The desorption liquid may contain an appropriate amount of organic solvent. Examples of organic solvents include water-soluble alcohols and water-soluble solvents with a flash point of 21°C or higher. Examples of water-soluble alcohols include methanol, ethanol, 1-propyl alcohol, and 2-propyl alcohol. Examples of water-soluble solvents with a flash point of 21°C or higher include diethylene glycol methyl ether, diethylene glycol butyl ether, propylene glycol propyl ether, and 3-methoxy-3-methyl-1-butanol. By using the above-mentioned water-soluble organic solvent, ions such as hydroxide ions generated from the alkali in the desorption liquid are less likely to be hydrated, thereby increasing the nucleophilicity of the ions. As a result, the recovery of recycled plastics (obtaining recycled polyolefin resin film pieces) can be performed more efficiently.

[0074] [Stirring] In the immersion step, stirring is preferably performed, although not essential. In this case, the laminate can be swollen more efficiently. The stirring device and stirring conditions are not particularly limited, and known devices can be appropriately used. For example, immersion with stirring can be performed using a container equipped with a motor-driven stirring blade, a container equipped with a means for generating ultrasonic waves, a container equipped with a shaking means, or the like.

[0075] [Immersion Temperature] The immersion temperature (temperature of the release solution during immersion) is not particularly limited as long as the release solution can be kept in a liquid state, and can be, for example, 15 to 90°C. However, a higher immersion temperature is preferable because it allows the immersion time to be shortened. Specifically, the preferred immersion temperature is 40°C or higher, 50°C or higher, or 60°C or higher, although this differs depending on the composition of the release solution.

[0076] [Immersion Time] In the immersion step, the immersion time is preferably a time sufficient to swell the laminate, specifically, 30 minutes or more. From the viewpoint of processing efficiency, the immersion time is preferably 48 hours or less. When the immersion temperature is room temperature, an immersion time of 24 hours can sufficiently swell the laminate. When the immersion temperature is, for example, 40°C, an immersion time of 16 hours can sufficiently swell the laminate. When the immersion temperature is, for example, 75°C, an immersion time of 120 minutes can sufficiently swell the laminate. Furthermore, the immersion time can be appropriately adjusted by combining the presence or absence of stirring and the immersion temperature as described above.

[0077] (Cleaning Step) After the immersion step, the laminate may be contaminated with a release solution containing an alkali. Therefore, in the method of the present embodiment, a cleaning step of cleaning the laminate may be carried out after the immersion step, without any particular limitation, in order to remove the adhering alkali. Water is usually used to clean the laminate.

[0078] (Wet-Crushing Step) In the method of the present embodiment, the laminate after the immersion step is wet-crushed in the presence of water to produce film pieces of recycled polyolefin resin derived from the polyolefin film layer of the laminate.

[0079] By including the wet crushing step in the method of this embodiment, the peak intensity ratio P ０４０ / P １１０ is effectively reduced, and as a result, the extensibility of the molded article can be improved.

[0080] The wet crushing may be carried out using any device that can crush the laminate in the presence of water, and may be carried out using, for example, a device having a mechanism for applying shear force and / or friction force to the laminate in water.

[0081] The wet crushing may be carried out continuously or batchwise. However, from the viewpoint of productivity, it is preferable to carry out the wet crushing continuously. When carried out continuously, the residence time of the material to be treated can be, for example, 10 seconds or more, 20 seconds or more, or 30 seconds or more, and can be 10 minutes or less, 5 minutes or less, or 2 minutes or less. In this case, specific changes in the crystal structure of the polyolefin film layer can be more effectively brought about while maintaining high productivity and processing efficiency.

[0082] In the case of continuous processing, the processing speed of the laminate can be, for example, 100 g / min or more, 200 g / min or more, or 300 g / min or more, and 2000 g / min or less, 1500 g / min or less, or 1000 g / min or less, which can more effectively bring about a specific change in the crystalline structure of the polyolefin film layer while maintaining high productivity and processing efficiency.

[0083] Wet crushing can be carried out using an apparatus equipped with a dispersing medium such as rods or beads. That is, wet crushing can be carried out while dispersing the laminate in water using a dispersing medium such as rods or beads. Examples of apparatus equipped with such a dispersing medium include a paint shaker, a ball mill, a vibration mill, an attritor, and a bead mill.

[0084] When a rod is used as the dispersion medium, examples of the material of the rod include steel, zirconia, alumina, and stainless steel. The diameter of the rod is preferably 12 mm or more, and is preferably 35 mm or less, more preferably 24 mm or less, and even more preferably 19 mm or less. When the diameter of the rod is 12 mm or more, the rod is easy to handle and can prevent problems such as twisting within the device. When the diameter of the rod is 35 mm or less, the rod can be sufficiently contacted with the laminate within a predetermined time, preventing a decrease in productivity.

[0085] When beads are used as the dispersion medium, examples of the material of the beads include steel, zirconia, alumina, stainless steel, and glass. The diameter (sphere diameter) of the beads is preferably 0.5 mm or more, more preferably 5 mm or more, and even more preferably 10 mm or more, and is preferably 35 mm or less, more preferably 30 mm or less, and even more preferably 25 mm or less. Beads with a diameter of 0.5 mm or more are easy to handle and can prevent the beads from becoming mixed with the laminate (film pieces) to be treated, making it difficult to recover them. Beads with a diameter of 35 mm or less can ensure a sufficient number of contacts with the laminate within a given time period, thereby preventing a decrease in productivity.

[0086] When wet crushing is performed using a device equipped with a dispersion medium, the filling rate of the dispersion medium in the container is preferably 30 vol% or more and 80 vol% or less. If the filling rate is 30 vol% or more, the frequency of contact with the laminate is sufficiently maintained, and a decrease in productivity can be suppressed. Furthermore, if the filling rate is 80 vol% or less, sufficient energy can be applied to the laminate to efficiently obtain recycled polyolefin resin film pieces.

[0087] The wet crushing is preferably carried out under the action of shaking or beating. In this case, the peak intensity ratio P ０４０ / P １１０ This more effectively reduces the strain, and as a result, the extensibility of the molded product can be improved.

[0088] "Shaking" refers to the action (operation) of shaking. Shaking can be achieved by using a device having a shaking mechanism. Examples of such devices include a paint shaker, a ball mill, a vibration mill, an attritor, and a bead mill. "Beating" refers to the operation of mechanically beating and loosening an object to be treated in the presence of a liquid. Beating can be achieved by using a device having a beating mechanism (a beater). Examples of such devices include a beater, a refiner, and a beat refiner.

[0089] The recycled polyolefin resin film pieces generated in the wet crushing process can be recovered prior to the subsequent molding process. The recovery method is not particularly limited, and examples thereof include conventional methods such as gravity separation in a liquid such as water. Furthermore, it is preferable to thoroughly remove moisture from the recovered recycled polyolefin resin film pieces prior to the subsequent molding process.

[0090] (Rinsing Step) Substances not intended for recovery, such as functional layers, may remain on or adhere to the surfaces of the film pieces obtained in the wet-crushing step. Therefore, the method of the present embodiment preferably further includes a rinsing step of washing the film pieces with a rinse liquid after the wet-crushing step (and before the molding step).

[0091] The cleaning with the rinse solution may be accompanied by stirring. The stirring device and stirring conditions are not particularly limited, and known devices can be appropriately used. For example, immersion with stirring can be performed using a container equipped with a motor-driven stirring blade, a container equipped with a means for generating ultrasonic waves, a container equipped with a shaking means, or the like.

[0092] Washing with a rinse solution can be carried out using an apparatus equipped with a dispersing medium such as rods or beads, etc. The apparatus equipped with such a dispersing medium is the same as that described above in the wet crushing step.

[0093] The rinse liquid preferably contains a water-soluble solvent. Examples of water-soluble solvents include water-soluble alcohols and water-soluble solvents having a flash point of 21°C or higher. Examples of water-soluble alcohols include methanol, ethanol, 1-propyl alcohol, and 2-propyl alcohol. Examples of water-soluble solvents having a flash point of 21°C or higher include diethylene glycol methyl ether, diethylene glycol butyl ether, propylene glycol propyl ether, and 3-methoxy-3-methyl-1-butanol.

[0094] From the viewpoint of improving cleaning efficiency, the proportion of the water-soluble solvent in the rinse liquid is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and still more preferably 90% by mass or more.

[0095] (Molding step) In the method of the present embodiment, the film pieces of recycled polyolefin resin obtained in the wet crushing step are molded in the molding step, and a molded product is finally obtained through this molding step.

[0096] The shape of the final molded product is not particularly limited and can be changed appropriately depending on the purpose.

[0097] In the molding process, the resin raw material can be the film pieces obtained in the wet crushing process alone, or a composition containing the film pieces and other resins. The other resins are preferably resins compatible with the recycled polyolefin resin that constitutes the film pieces, specifically thermoplastic resins (virgin thermoplastic resins) such as polyethylene resin and polypropylene resin. These other resins can be used alone or in combination of two or more.

[0098] The content of film pieces in the entire resin raw material to be subjected to the molding process is preferably 50% by mass or more. In this case, the recycling rate is at a sufficiently high level. In addition, the content of film pieces in the resin raw material being 50% by mass or more is also important in terms of the peak intensity ratio P ０４０ / P １１０This can also contribute to a reduction in the amount of the film pieces. The content of the film pieces refers to the proportion of the film pieces in the entire resin raw material used in the molding process. From the same viewpoint, the content of the film pieces is more preferably 60% by mass or more, even more preferably 75% by mass or more, and even more preferably 90% by mass or more. It is also preferable that the content of the film pieces is 100% by mass (i.e., the resin raw material used in the molding process consists solely of the film pieces).

[0099] The composition to be subjected to the molding step may contain appropriate amounts of metal soaps of alkali metals, alkaline earth metals, or zinc; hydrotalcite; surfactants such as nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants; antistatic agents; flame retardants such as halogen-based, phosphorus-based, or metal oxide flame retardants; lubricants such as ethylene bisalkylamides; antioxidants; ultraviolet absorbers; fillers; colorants; peroxides, etc., within limits that do not impair the effects of the present invention.

[0100] In the molding process, a molded product may be directly produced using the recycled polyolefin resin film pieces, or an intermediate molding material such as pellets may be first produced using the recycled polyolefin resin film pieces, and then a molded product may be produced using the intermediate molding material.

[0101] The molding step preferably includes melt-kneading and extruding the film pieces or a composition containing the film pieces. In this case, the peak intensity ratio P ０４０ / P １１０ This more effectively reduces the viscosity of the film, thereby improving the extensibility of the molded product. By melt-kneading and extruding the film pieces or a composition containing the film pieces, an intermediate molding material such as pellets can be obtained. This series of operations can be carried out using, for example, a kneader, a roll mill, a single-screw extruder, a twin-screw extruder, a rotor-type twin-screw kneader, or the like. Among these, it is preferable to use a twin-screw extruder in terms of processing efficiency, etc.

[0102] When a single-screw extruder or a twin-screw extruder is used, the melt-kneading temperature is preferably 180°C or higher, 190°C or higher, or 200°C or higher, and preferably 260°C or lower, 250°C or lower, or 240°C or lower.

[0103] When using a single-screw extruder or a twin-screw extruder, the screw rotation speed is preferably 50 rpm or more and 500 rpm or less. If the screw rotation speed is 50 rpm or more, a more uniform intermediate molding material can be obtained. Furthermore, if the screw rotation speed is 500 rpm or less, a significant decrease in the physical properties of the intermediate molding material can be suppressed. From the same viewpoint, the screw rotation speed is more preferably 100 rpm or more, even more preferably 180 rpm or more, and more preferably 400 rpm or less, even more preferably 300 rpm or less.

[0104] The feeding rate of the resin raw material during extrusion is preferably 5 kg / h or more and 100 kg / h or less. If the feeding rate is 5 kg / h or more, the resin pressure during extrusion increases, and a better kneaded state can be formed. Furthermore, if the feeding rate is 100 kg / h or less, device malfunctions such as clogging can be suppressed. From the same viewpoint, the feeding rate of the resin raw material during extrusion is more preferably 50 kg / h or less, and even more preferably 30 kg / h or less.

[0105] The resin pressure during extrusion is preferably 1 MPa or more and 30 MPa or less. If the resin pressure is 1 MPa or more, a better kneaded state can be formed. Furthermore, if the resin pressure is 30 MPa or less, device malfunctions such as clogging can be suppressed. From the same viewpoint, the resin pressure during extrusion is more preferably 25 MPa or less, and even more preferably 20 MPa or less.

[0106] The shape of the intermediate molding material obtained by the extrusion operation is not particularly limited, and may be, for example, pellet-like, powder-like, granular, or bead-like.

[0107] The resulting intermediate molding material such as pellets is then heat-molded to finally obtain a molded product. The heat-molding method is not particularly limited, and examples thereof include injection molding, extrusion molding, blow molding, and compression molding.

[0108] The heating temperature during heat molding is preferably 180°C or higher, 190°C or higher, or 200°C or higher, and preferably 260°C or lower, 250°C or lower, or 240°C or lower.

[0109] In the case of heat molding using a mold (such as injection molding), the mold temperature is preferably 20°C or higher and 60°C or lower. If the mold temperature is 20°C or higher, the fluidity of the molten resin can be maintained, and poor filling and the generation of bubbles can be prevented. Furthermore, if the mold temperature is 60°C or lower, the cooling rate of the molten resin can be maintained appropriately, and the shrinkage rate after molding can be suppressed. From the same viewpoint, the mold temperature is more preferably 30°C or higher, and more preferably 50°C or lower.

[0110] The holding pressure during heat molding is preferably 20 MPa or more and 100 MPa or less. If the holding pressure is 20 MPa or more, the quality of the molded product and therefore its surface can be improved. Furthermore, if the holding pressure is 100 MPa or less, release defects can be suppressed. From the same viewpoint, the holding pressure during heat molding is more preferably 30 MPa or more, even more preferably 40 MPa or more, and more preferably 70 MPa or less, and even more preferably 60 MPa or less.

[0111] The molding time during heat molding is preferably 10 seconds or more and 5 minutes or less. If the molding time is 10 seconds or more, a good molded product can be obtained by sufficient cooling. Furthermore, if the molding time is 5 minutes or less, productivity can be maintained at a good level. From the same viewpoint, the molding time is more preferably 20 seconds or more, even more preferably 25 seconds, and more preferably 2 minutes or less, even more preferably 1 minute or less.

[0112] (Molded Product Produced) In the method of this embodiment, the molded product produced by the above-described steps has a peak intensity P of the (110) plane in X-ray diffraction when molded to a thickness of 4 mm. １１０ The peak intensity P of the (040) plane ０４０ The ratio (P ０４０ / P １１０ ) is 1.00 or less. ０４０ / P １１０The feature of a peak intensity ratio P of 1.00 or less can typically be achieved by using a laminate having a polyolefin film layer and a functional layer as the treatment target, and by carrying out a predetermined immersion step, wet crushing step, and molding step. ０４０ / P １１０ can be adjusted based on the combined effects of, for example, the conditions of the wet crushing step, the conditions of the molding step, and the composition of the resin raw material used in the molding step.

[0113] In the method of this embodiment, the peak intensity ratio P ０４０ / P １１０ However, from the viewpoint of further improving the extensibility, the peak strength ratio P ０４０ / P １１０ is preferably 0.90 or less, more preferably 0.80 or less, and even more preferably 0.70 or less.

[0114] The molded product produced by the method of this embodiment has a recycled polyolefin resin content of 50% by mass or more. If the recycled polyolefin resin content is 50% by mass or more, the recycling rate will be at a sufficiently high level. In addition, the recycled polyolefin resin content of the molded product being 50% by mass or more means that the peak intensity ratio P ０４０ / P １１０ It can also contribute to a reduction in the amount of recycled polyolefin resin. The recycled polyolefin resin content refers to the proportion of recycled polyolefin resin in the total resin contained in the molded product. From the same perspective, the recycled polyolefin resin content is more preferably 60% by mass or more, even more preferably 75% by mass or more, and even more preferably 90% by mass or more. It is also preferable that the recycled polyolefin resin content is 100% by mass (i.e., the resin contained in the molded product consists solely of recycled polyolefin resin).

[0115] <Molded Article> A molded article according to one embodiment of the present invention (hereinafter, sometimes referred to as "molded article of this embodiment") is a molded article containing a polyolefin resin, and in a molded state with a thickness of 4 mm, the peak intensity P １１０The peak intensity P of the (040) plane ０４０ The ratio (P ０４０ / P １１０ ) is 1.00 or less. The molded article of this embodiment has such a feature, and therefore has excellent elongation. The shape of the molded article of this embodiment is not particularly limited. In addition, when the molded article is not in a molded state with a thickness of 4 mm, the peak strength P ０４０ The ratio (P ０４０ / P １１０ When specifying the thickness of the molded product, the molded product can be molded to a thickness of 4 mm in accordance with conventional methods.

[0116] The molded product of this embodiment can typically be produced by the method of this embodiment described above, and therefore, the description of the molded product produced by the method of this embodiment described above can be used to describe the details of the molded product of this embodiment.

[0117] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Furthermore, "%" in the compositions of the following examples means "% by mass" unless otherwise specified.

[0118] <Preparation of Polyolefin Film Layers> The following polyolefin film layers were prepared: PP1... Polypropylene film, "P2161" manufactured by Toyobo Co., Ltd., thickness: 20 μm PP2... Polypropylene film, "P2171" manufactured by Toyobo Co., Ltd., thickness: 20 μm PP3... Polypropylene film, "FOR" manufactured by Futamura Chemical Co., Ltd., thickness: 20 μm PP5... Polypropylene film, "P1128" manufactured by Toyobo Co., Ltd., thickness: 30 μm PP6... Polypropylene film, "VM-CPP" manufactured by Toray Industries, Inc., thickness: 30 μm

[0119] <Preparation of Composition for Removable Primer Layer (1)> 0.32 g of terephthalic acid (TPA), 0.32 g of isophthalic acid (IPA), 0.13 g of ethylene glycol (EG), and 0.23 g of diethylene glycol (DEG) were mixed and reacted to prepare polyol (a) (aromatic polyester polyol).

[0120] Next, 0.74 g of polyol (a), 0.20 g of isophorone diisocyanate, and 0.06 g of 2,2′-dimethylolpropionic acid were charged into a four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, and the mixture was reacted at 75° C. for 8 hours under a nitrogen stream to obtain a urethane resin (1).

[0121] Next, the urethane resin (1) was diluted with isopropyl alcohol so that the solid content concentration of the urethane resin (1) became 10%, thereby obtaining a composition for a removable primer layer (1).

[0122] <Preparation of Composition for Removable Primer Layer (2)> 10 parts by mass of PVA1 (polyvinyl alcohol, PVA-A, weight average molecular weight: 48,000), 45.0 parts by mass of water, and 45.0 parts by mass of ethanol were mixed to obtain a composition for removable primer layer (2).

[0123] <Preparation of Composition for Removable Primer Layer (3)> 10 parts by mass of PVA-2 (polyvinyl alcohol, manufactured by Nippon Vinyl Acetate & Poval Co., Ltd., J-POVAL JF-05, weight average molecular weight: 22,000), 0.5 parts by mass of polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd.), 44.5 parts by mass of water, and 45.0 parts by mass of ethanol were mixed to obtain a composition for removable primer layer (3).

[0124] <Preparation of Composition for Removable Primer Layer (4)> 10 parts by mass of PVA-3 (polyvinyl alcohol, manufactured by Nippon Vinyl Acetate & Poval Co., Ltd., J-POVAL JF-17, weight average molecular weight: 75,000), 1.0 part by mass of polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd.), 44.0 parts by mass of water, and 45.0 parts by mass of ethanol were mixed to obtain a composition for removable primer layer (4).

[0125] <Preparation of Composition for Removable Primer Layer (5)> 10 parts by mass of PVA-4 (polyvinyl alcohol, manufactured by Kuraray Co., Ltd., KURARAY POVAL 60-98, weight average molecular weight: 106,000), 3.0 parts by mass of polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd.), 42.0 parts by mass of water, and 45.0 parts by mass of ethanol were mixed to obtain a composition for removable primer layer (5).

[0126] <Preparation of Adhesive Layer Composition> The adhesive layer composition was prepared by mixing DICDRY (registered trademark) LX-510 manufactured by DIC Corporation and DICDRY (registered trademark) KW-75 manufactured by DIC Corporation in a mass ratio of LX-510:KW-75=9:1, and then diluting the mixture with ethyl acetate as a solvent (a polyurethane-based two-component curing laminating adhesive).

[0127] <Preparation of composition for printing layer (white)> As the composition for the printing layer (white), a urethane-based laminating ink (Finart R794 White S, manufactured by DIC Corporation) was used, the viscosity of which was adjusted to 15 seconds (25°C) using a Zahn Cup #3 manufactured by Rigo Co., Ltd.

[0128] <Preparation of composition for printing layer (indigo)> For the composition for the printing layer (indigo), a surface printing gravure ink (Glossa 507 Primary Indigo S2, manufactured by DIC Graphics) was used, with its viscosity adjusted to 15 seconds (25°C) using a Zahn Cup #3 manufactured by Rigo Co., Ltd.

[0129] <Preparation of Laminate (LAM1)> A composition for a printing layer (white) was tightly coated onto PP1 as a polyolefin film layer using a gravure printing machine equipped with a gravure plate with a plate depth of 43 μm. The coating was then passed through an oven at 70°C to dry and cure, forming a printing layer (white) on PP1. Next, a composition for an adhesive layer was applied onto the printing layer (white) in an amount (solid content) of 4 g / m. ２ The composition was applied using an RDS Mayer coating bar so that the adhesive layer composition was uniform. Next, the solvent in the adhesive layer composition was volatilized using a dryer. Meanwhile, the composition for the removable primer layer (1) was applied tightly (solidly) to PP5 as a polyolefin film layer using a gravure printing machine. Next, the composition was dried at 90°C for 1 minute to form a removable primer layer (1) on PP5. Next, the polyolefin film layers were bonded together so that the adhesive composition on PP1 and the removable primer layer (1) on PP5 were in contact. Then, aging was performed at 40°C for 5 days to obtain a laminate (LAM1) having a layer structure of "PP1 / printed layer (white) / adhesive layer / detachable primer layer (1) / PP5".

[0130] <Preparation of Laminate (LAM2)> A composition for a removable primer layer (1) was tightly applied onto PP2 as a polyolefin film layer using a gravure printing machine. The applied composition was then dried at 90°C for 1 minute to form a removable primer layer (1) on PP2. A composition for a printing layer (white) was then applied onto the removable primer layer (1) without any gaps using a gravure printing machine equipped with a gravure plate with a plate depth of 43 μm. The resulting mixture was then passed through an oven at 70°C to dry and cure, forming a printing layer (white) on the removable primer layer (1). A composition for an adhesive layer was then applied onto the printing layer (white) in an amount (solids content) of 4 g / m. ２ The composition was applied using an RDS Mayer coating bar so that the adhesive layer composition was uniform. Next, the solvent in the adhesive layer composition was evaporated using a dryer. Meanwhile, the composition for the removable primer layer (1) was tightly coated on PP5 as a polyolefin film layer using a gravure printing machine. Next, the coating was dried at 90°C for 1 minute to form a removable primer layer (1) on PP5. Next, the polyolefin film layers were bonded together so that the adhesive composition on PP2 and the removable primer layer (1) on PP5 were in contact. Then, aging was performed at 40°C for 5 days to obtain a laminate (LAM2) having a layer structure of "PP2 / Removable primer layer (1) / Printing layer (white) / Adhesive layer / Removable primer layer (1) / PP5".

[0131] <Preparation of Laminate (LAM3)> A composition for a removable primer layer (1) was tightly applied onto PP3 as a polyolefin film layer using a gravure printing machine. The applied composition was then dried at 90°C for 1 minute to form a removable primer layer (1) on PP3. A composition for a printing layer (white) was then applied onto the removable primer layer (1) without any gaps using a gravure printing machine equipped with a gravure plate with a plate depth of 43 μm. The resulting mixture was then passed through an oven at 70°C to dry and cure, forming a printing layer (white) on the removable primer layer (1). A composition for an adhesive layer was then applied onto the printing layer (white) in an amount (solids content) of 4 g / m. ２The adhesive layer composition was applied using an RDS Meyer coating bar so that the adhesive layer composition was formed on the PP3. The solvent in the adhesive layer composition was then evaporated using a dryer. PP5 was then attached to the adhesive layer composition on the PP3 as a polyolefin film layer. Aging was then carried out at 40°C for 5 days to obtain a laminate (LAM3) having a layer structure of "PP3 / Removable primer layer (1) / Printed layer (white) / Adhesive layer / PP5".

[0132] <Preparation of Laminate (LAM5)> A composition for a removable primer layer (1) was tightly applied onto PP1 as a polyolefin film layer using a gravure printing machine. The applied composition was then dried at 90°C for 1 minute to form a removable primer layer (1) on PP1. A composition for a printing layer (white) was then applied onto the removable primer layer (1) without any gaps using a gravure printing machine equipped with a gravure plate with a plate depth of 43 μm. The resulting mixture was then passed through an oven at 70°C to dry and cure, forming a printing layer (white) on the removable primer layer (1). A composition for an adhesive layer was then applied onto the printing layer (white) in an amount (solid content) of 4 g / m. ２ The adhesive layer composition was applied using an RDS Meyer coating bar so that the adhesive layer composition was formed on the PP1. The solvent in the adhesive layer composition was then evaporated using a dryer. PP6 was then laminated to the adhesive layer composition on the PP1 as a polyolefin film layer. Aging was then carried out at 40°C for 5 days to obtain a laminate (LAM5) having a layer structure of "PP1 / removable primer layer (1) / printed layer (white) / adhesive layer / PP6".

[0133] <Preparation of Laminate (LAM6)> A composition for a removable primer layer (2) was applied to PP1 as a polyolefin film layer in an amount (solid content) of 0.5 g / m ２The coating was applied without gaps using a gravure printing machine equipped with a gravure plate with a plate depth of 22 μm so that the coating was uniform. The coating was then dried by passing through an oven at 70°C. The coating was then left at room temperature for one day to form a removable primer layer (2) on PP1. An adhesive layer composition was then applied onto the removable primer layer (2). PP5 was then laminated as a polyolefin film layer onto the adhesive layer composition on PP1. Aging was then performed at 40°C for three days to obtain a laminate (LAM6) having a layer structure of "PP1 / removable primer layer (2) / adhesive layer / PP5."

[0134] <Preparation of Laminate (LAM7)> A composition for a removable primer layer (3) was applied to PP1 as a polyolefin film layer in an amount (solid content) of 0.5 g / m ２ The composition was tightly coated using a gravure printing machine equipped with a gravure plate with a plate depth of 22 μm so that the resulting coating was uniform. The coating was then dried by passing through an oven at 70°C. This was then left at room temperature for one day to form a removable primer layer (3) on PP1. A composition for a printing layer (white) was then tightly coated onto this removable primer layer (3) using a gravure printing machine equipped with a gravure plate with a plate depth of 43 μm. This was then dried and cured by passing through an oven at 70°C to form a printing layer (white) on the removable primer layer (3). An adhesive layer composition was then coated onto this printing layer (white). PP5 was then bonded to the adhesive layer composition on PP1 as a polyolefin film layer. Aging was then performed at 40°C for three days to obtain a laminate (LAM7) having a layer structure of "PP1 / removable primer layer (3) / printing layer (white) / adhesive layer / PP5."

[0135] <Preparation of Laminate (LAM8)> A composition for a removable primer layer (4) was applied to PP1 as a polyolefin film layer in an amount (solid content) of 0.5 g / m ２The coating was tightly applied using a gravure printing machine equipped with a gravure plate with a plate depth of 22 μm so that the coating was uniform. The coating was then passed through an oven at 70°C for drying. The coating was then left at room temperature for one day to form a removable primer layer (4) on PP1. An adhesive layer composition was then applied onto the removable primer layer (4). Meanwhile, the removable primer layer (4) composition was applied tightly onto PP5 as a polyolefin film layer using a gravure printing machine. The coating was then passed through an oven at 70°C for drying. The coating was then left at room temperature for one day to form a removable primer layer (4) on PP5. The polyolefin film layers were then bonded together so that the adhesive layer composition on PP1 and the removable primer layer (4) on PP5 were in contact. Then, aging was carried out at 40° C. for 3 days to obtain a laminate (LAM8) having a layer structure of "PP1 / removable primer layer (4) / adhesive layer / removable primer layer (4) / PP5".

[0136] <Preparation of Laminate (LAM9)> A composition for a removable primer layer (5) was applied to PP1 as a polyolefin film layer in an amount (solid content) of 0.5 g / m ２The composition was tightly coated using a gravure printing machine equipped with a gravure plate with a plate depth of 22 μm so that the resulting coating was uniform. The coating was then dried by passing through an oven at 70°C. This was then left at room temperature for one day to form a removable primer layer (5) on PP1. A composition for a printing layer (white) was then tightly coated onto this removable primer layer (5) using a gravure printing machine equipped with a gravure plate with a plate depth of 43 μm. This was then dried and cured by passing through an oven at 70°C to form a printing layer (white) on the removable primer layer (5). An adhesive layer composition was then coated onto this printing layer (white). Meanwhile, the composition for a removable primer layer (5) was tightly coated onto PP5 as a polyolefin film layer using a gravure printing machine. This was then dried by passing through an oven at 70°C. This was then left at room temperature for one day to form a removable primer layer (5) on PP5. Next, the polyolefin film layers were bonded together so that the adhesive layer composition on PP1 and the removable primer layer (5) on PP5 were in contact with each other. Then, aging was carried out at 40°C for 3 days to obtain a laminate (LAM9) having a layer structure of "PP1 / removable primer layer (5) / printed layer (white) / adhesive layer / removable primer layer (5) / PP5".

[0137] <Preparation of Laminate (Surface Printed Material, Pri1)> The composition for the printing layer (indigo) was tightly coated onto PP1 as a polyolefin film layer using a gravure printing machine equipped with a gravure plate with a plate depth of 43 μm. The coating was then dried and cured by passing through an oven at 70°C to form a printing layer (indigo) on PP1. In this way, a laminate (Pri1) having a layer structure of "PP1 / printed layer (indigo)" was obtained.

[0138] <Preparation of Laminate (Surface Printed Material, Pri2)> A composition for a removable primer layer (1) was tightly applied onto PP1 as a polyolefin film layer using a gravure printer. This was then dried at 90°C for 1 minute to form a removable primer layer (1) on PP1. Next, a composition for a printing layer (indigo) was applied onto this removable primer layer (1) tightly using a gravure printer equipped with a gravure plate with a plate depth of 43 μm. This was then dried and cured by passing through an oven at 70°C to form a printing layer (indigo) on the removable primer layer (1). In this way, a laminate (Pri2) having a layer structure of "PP1 / removable primer layer (1) / printing layer (indigo)" was obtained.

[0139] <Preparation of Laminate (Surface Printed Material, Pri3)> A composition for a removable primer layer (2) was tightly applied onto PP1 as a polyolefin film layer using a gravure printer. This was then dried at 90°C for 1 minute to form a removable primer layer (2) on PP1. Next, a composition for a printing layer (indigo) was applied onto this removable primer layer (2) tightly using a gravure printer equipped with a gravure plate with a plate depth of 43 μm. This was then dried and cured by passing through an oven at 70°C to form a printing layer (indigo) on the removable primer layer (2). In this way, a laminate (Pri3) having a layer structure of "PP1 / removable primer layer (2) / printing layer (indigo)" was obtained.

[0140] The layer structure of each laminate produced is shown in Table 1.

[0141]

[0142] <Production of Molded Articles> (Pretreatment Step) Each of the produced laminates was placed in a dry crusher equipped with a screen having a hole diameter of 10 mm, and pretreated to have a short side of approximately 5 to 10 mm and a long side of approximately 10 to 20 mm.

[0143] (Immersion Step) The laminate after the pretreatment step was subjected to the following immersion step (A) or immersion step (B). Immersion step (A): A release liquid selected from release liquids (1) to (4) shown in Table 2 was used as the release liquid, and 2 kg of the laminate was placed in 15 L of the release liquid. The laminate was then immersed in the release liquid at 40°C for 16 hours. Immersion step (B): A release liquid selected from release liquids (1) to (4) shown in Table 2 was used as the release liquid, and 2 kg of the laminate was placed in 15 L of the release liquid. The laminate was then immersed in the release liquid at 75°C for 120 minutes while stirring at 300 rpm using a Three-One Motor.

[0144]

[0145] Alkali: sodium hydroxide Surfactant (1): Dai-ichi Kogyo Seiyaku Co., Ltd.'s "DKS NL Dash 403", polyalkyl alkylene lauryl ether, HLB value = 6.5 Surfactant (2): Dai-ichi Kogyo Seiyaku Co., Ltd.'s "DKS NL Dash 408", polyalkyl alkylene lauryl ether, HLB value = 12.5 Surfactant (3): NOF Corporation's "M2-100R", cationic surfactant

[0146] (Washing Step) After the immersion step, the laminate was showered with water to wash off the alkali until the pH fell within the range of 7 to 12, and then the laminate was placed in a colander and lightly dehydrated.

[0147] (Wet-Crushing Step) Next, the laminate was subjected to the following wet-crushing step (a), wet-crushing step (b), or wet-crushing step (c) to obtain film pieces. Wet-crushing step (a): A continuous vibration mill manufactured by Chuo Kakoki Co., Ltd. was used as the wet-crushing device. 2 kg of the laminate was used, and the ratio of the laminate to water was adjusted to 150 g / 1 L. The vibration mill used had a dispersion medium in its container. As the dispersion medium, a 19 mm diameter rod was used, and the filling rate of the dispersion medium in the container was 60 vol%. The amount of water flowing in was adjusted so that the laminate introduced was discharged outside the machine within 1 minute, and the laminate was wet-crushed (with shaking). The processing speed of the laminate at this time was 500 g / min. Wet-Crushing Step (b): A beat refiner manufactured by Satomi Seisakusho Co., Ltd. was used as the wet-crushing device. 2 kg of the laminate was used, and the ratio of the laminate to water was adjusted to 100 g / 1 L. The blade design of the fixed and rotary blades in the beat refiner used was such that the blades arranged in the radial direction were inclined 30° from the radial direction, the blade width of the rotary blade was 3 mm, the groove width between the blades was 0.3 mm, and the blade height was 3 mm. The clearance between the fixed and rotary blades was set to 1 mm, and the beat refiner was operated at a peripheral speed of 24 m / s. The amount of water flowing in was adjusted so that the input laminate was discharged outside the machine within 1 minute, and the laminate was wet-crushed (with beating action). The processing speed of the laminate at this time was 500 g / min. Wet-crushing step (c): A washing and crushing machine "PFS-40" (grid mesh size = 5 mmΦ) manufactured by Nippon Seam Co., Ltd. was used as the wet-crushing device. Using 2 kg of the laminate, the machine was operated at 600 rpm while supplying water at 15 L / min, to wet-crush the laminate (without shaking or beating).

[0148] (Rinsing step) The film pieces obtained in the wet crushing step were washed with a rinse solution. Specifically, 1 kg of the film pieces was placed in 10 L of diethylene glycol methyl ether as a rinse solution, and the mixture was stirred using a Three-One motor (rotation speed: 500 rpm) for 30 minutes.

[0149] The film pieces after the wet crushing and rinsing processes were subjected to gravity separation in water using a water tank-type gravity separator manufactured by Nippon Seam Co., Ltd. During this process, the polyolefin resin (film pieces of recycled polyolefin resin) floated, while the other components settled. The floating film pieces were collected and centrifuged at 500 rpm to remove water. The pieces were then left to dry at 60°C for 1 day.

[0150] (Molding Process (Extrusion)) 0.3% of an antioxidant (Irganox 1010) was blended into the film pieces after the wet-crushing process and the rinsing process (in the example where the wet-crushing process was not performed, the laminate after the immersion process and the washing process). A twin-screw extruder "KZW" (L / D = 45) manufactured by Technovel Corporation was used as the extrusion device. The film pieces were fed into the twin-screw extruder at a rate of 5 kg / h with a melt-kneading temperature of 200°C and a screw rotation speed of 300 rpm. After melt-kneading, the film pieces were extruded and pelletized. The resin pressure during this process was 1 to 2 MPa. In Comparative Example 1, virgin polypropylene resin ("FL203D" manufactured by Japan Polypropylene Corporation) was used so that it accounted for 40% of the total resin raw material fed into the twin-screw extruder. That is, in Comparative Example 1, the content of film pieces in the total resin raw material was 60%.

[0151] (Molding Step (Injection Molding)) The pellets obtained by extrusion (in the case of an example in which extrusion was not performed, film pieces after the wet crushing step) were used to perform injection molding using an injection molding machine "MS100" manufactured by Sodick Corporation to prepare dumbbell test pieces (molded products) having a thickness of 4 mm. The injection molding conditions were an injection temperature (heating temperature) of 200°C, a mold temperature (cooling temperature) of 40°C, an indentation pressure of 90 MPa, a holding pressure of 50 MPa, and a molding time (cooling time) of 30 seconds.

[0152] <Measurements and Evaluations> In the series of operations described above, the following measurements and evaluations were carried out. The results are shown in Tables 3 and 4.

[0153] (Releasability) The area of ​​peeled portions relative to the total area was measured for film pieces after the wet crushing step and rinsing step (in examples where the wet crushing step was not performed, the laminate after the immersion step and washing step). The measured peeled area was scored according to the following criteria. The higher the score, the better the releasability. 1 point: peeled area is less than 10%; 2 points: peeled area is 10% or more but less than 50%; 3 points: peeled area is 50% or more but less than 100%; 4 points: peeled area is 100%

[0154] (Peeling Condition) After the wet crushing process, the film pieces were observed for the peeling condition of the printed layer (white), the printed layer (indigo), or the adhesive layer (hereinafter referred to as the functional layer), and evaluated according to the following criteria: Film-like: The functional layer peeled off in a film state in chunks to some extent. Powder-like: The functional layer peeled off in a powder state.

[0155] (Ratio of peak intensities in X-ray diffraction of molded product (P ０４０ / P １１０ )) The dumbbell test piece (molded product) obtained by injection molding was left to stand for one week in a room at a temperature of 22°C and a humidity of 50%. Next, the dumbbell test piece (molded product) was analyzed by X-ray diffraction using an X-ray diffractometer "SmartLab SE" manufactured by Rigaku Corporation. As the diffraction angle (2θ), 14.1° was assigned to the (110) plane, and 16.9° was assigned to the (040) plane. The peak intensity P １１０ The peak intensity P of the (040) plane ０４０ The ratio (P ０４０ / P １１０ ) was evaluated.

[0156] (Elongation at break of molded product) Dumbbell test pieces (molded products) obtained by injection molding were elongated at a rate of 100 mm / min in accordance with JIS K6301 to measure the elongation at break. The number of measurements was 10 per level, and the average value of 6 points, excluding the two highest and two lowest measured values, was used. The larger this value, the higher the extensibility.

[0157]

[0158]

[0159] As can be seen from Tables 3 and 4, in the examples according to the present invention, molded products were manufactured by carrying out predetermined steps, and the molded products obtained in these examples had peak intensity ratios P ０４０ / P １１０ It can be seen that the elongation coefficient is 1.00 or less. It can also be seen that the molded articles obtained in the examples are superior in elongation compared to the comparative examples.

[0160] According to the present invention, a method for producing a molded article can be provided that recovers recycled plastic from a laminate including a plastic film layer and a functional layer, and that produces a molded article having excellent stretchability. Furthermore, according to the present invention, a molded article having excellent stretchability that can be produced by the above-mentioned production method can be provided.

Claims

1. A method for producing a molded product, comprising recovering recycled polyolefin resin from a laminate comprising a polyolefin film layer and a functional layer, and using the recycled polyolefin resin to produce a molded product, the method comprising: an immersion step of immersing the laminate in a release solution containing an alkali; a wet-crushing step of wet-crushing the laminate after the immersion step in the presence of water to obtain film pieces of recycled polyolefin resin; and a molding step of molding using the film pieces to obtain a molded product, wherein the molded product has a recycled polyolefin resin content of 50% by mass or more, and has a peak intensity P of the (110) plane in X-ray diffraction when molded to a thickness of 4 mm. １１０ The peak intensity P of the (040) plane ０４０ The ratio (P ０４０ / P １１０ ) is 1.00 or less.

2. The method according to claim 1, wherein the wet crushing is carried out under the action of shaking or beating.

3. The method according to claim 1 or 2, wherein the molding step includes melt-kneading and extruding the film pieces or a composition containing the film pieces.

4. The method according to claim 1 or 2, further comprising a rinsing step of washing the film pieces with a rinsing liquid after the wet-crushing step.

5. The method of claim 4, wherein the rinse solution contains a water-soluble solvent.

6. A molded product containing polyolefin resin, in which the peak intensity P of the (110) plane in X-ray diffraction when molded to a thickness of 4 mm １１０ The peak intensity P of the (040) plane ０４０ The ratio (P ０４０ / P １１０ ) is 1.00 or less.

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