JP7439884B1 - Packaging material, method for producing the same, and method for producing recycled polyolefin - Google Patents

Abstract

An object of the present invention is to provide a packaging material with excellent lamination strength, oxygen barrier properties, separability, and recyclability. A packaging material having a base material 1, a barrier layer, a printed layer, and a base material 2, the packaging material containing 80% by mass or more of a polyolefin resin in the total mass of the packaging material, A packaging material, wherein the barrier layer contains a polyvinyl alcohol resin, and the printing layer contains a polyvinyl acetal resin. The above packaging material is for recycled polyolefin. [Selection diagram] None

Description

The present invention relates to a packaging material, a method for producing the same, and a method for producing recycled polyolefin.

In recent years, packages made of plastic films such as polyolefin, plastic bottles, and other plastic products have been discarded or dumped as garbage in the ocean, causing environmental pollution problems. Plastic products are crushed in seawater and become submicron-sized fragments (microplastics) that float in the seawater. Microplastics are ingested by marine organisms such as fish and become concentrated within their bodies. Therefore, there are concerns about the impact on the health of seabirds, humans, and others who consume marine organisms as food. In order to solve the above environmental pollution problem, it is desired to develop technologies related to sustainable use of plastic products and reduction of the amount of plastic products disposed of.

In multilayer food packaging packages, various plastic base materials are used as film base materials, such as polyester base material, nylon base material (NY), polypropylene base material (PP), and polyethylene base material (PE). . A food packaging package with a multilayer structure is produced by, for example, printing a first film base material with printing ink, and pasting a second film base material on the printed layer, if necessary, with an adhesive layer interposed therebetween. After combining them, they are cut and heat-sealed to form the package. However, due to compatibility and other issues, multilayered food packaging packages containing multiple dissimilar materials are difficult to materially recycle. Therefore, development of packaging materials made of similar materials is underway.

Patent Document 1 describes a packaging material having a structure of polyethylene base material/adhesive/polyethylene base material, but since polyethylene has low oxygen barrier properties, a packaging material with good oxygen barrier properties is required. There is. Furthermore, Patent Document 2 describes a packaging material having a polypropylene base material/printed layer structure, in which the binder resin of the printed layer is polyvinyl butyral resin, and the development of chlorine-free packaging materials is progressing. .

JP 2019-189334 Publication JP2022-96163A

An object of the present invention is to provide a packaging material with excellent lamination strength, oxygen barrier properties, and recyclability.

As a result of extensive research into the above-mentioned problems, the inventors have discovered that the above-mentioned problems can be solved by using the packaging material described below, and have accomplished the present invention.

That is, the present invention is a packaging material having a base material 1, a barrier layer, a printed layer, and a base material 2,
The packaging material contains 80% by mass or more of a polyolefin resin in the total mass of the packaging material,
The barrier layer contains a polyvinyl alcohol resin,
The present invention relates to a packaging material in which the printing layer contains a polyvinyl acetal resin.

The present invention also relates to the above-mentioned packaging material for recycled polyolefin.

The present invention also relates to the above-mentioned packaging material, wherein the polyvinyl acetal resin is a polyvinyl butyral resin.

The present invention also relates to the above-mentioned packaging material, wherein the weight average molecular weight of the polyvinyl butyral resin is 25,000 to 200,000.

Further, the present invention provides the above-mentioned packaging material, wherein the polyvinyl alcohol-based resin contains a structural unit derived from ethylene, and the content of the ethylene-derived structural unit is 1 to 40 mol% of the entire polyvinyl alcohol-based resin. Regarding.

The present invention also relates to the above packaging material, wherein the barrier layer contains an inorganic layered filler.

The present invention also relates to the above-mentioned packaging material, wherein the inorganic layered filler is at least one selected from the group consisting of montmorillonite, mica, and kaolin.

The present invention also relates to the above packaging material, wherein the content of the inorganic layered filler in the total mass of the barrier layer is 1 to 40% by mass.

Moreover, the present invention relates to the above-mentioned packaging material, wherein the printing layer further contains a urethane resin.

The present invention also relates to the above packaging material, wherein the ratio of polyvinyl butyral resin to urethane resin is 1:99 to 85:15.

The present invention also relates to the above packaging material, wherein the polyolefin resin is polypropylene.

The present invention also relates to the above packaging material, wherein the polyolefin resin is polyethylene.

The present invention also provides a method for producing a packaging material having a base material 1, a barrier layer, a printed layer, and a base material 2, and containing 80% by mass or more of a polyolefin resin,
printing a barrier coating agent containing polyvinyl alcohol resin to form a barrier layer with a coating amount of 0.5 to 3 g/ ^m2 ;
The present invention relates to a method for manufacturing a packaging material, including a step of printing a printing ink containing polyvinyl butyral resin to form a printing layer.

The present invention also provides a method for producing recycled polyolefin, which obtains recycled polyolefin resin from a packaging material using an extrusion device equipped with a first screw and a discharge section,
The packaging material has a base material 1, a barrier layer, a printed layer, and a base material 2, and contains 80% by mass or more of a polyolefin resin,
The barrier layer contains a polyvinyl alcohol resin,
The printing layer contains polyvinyl acetal resin,
Production of recycled polyolefin, comprising: a heating melt-kneading step of heating and melting and kneading the packaging material using the first screw to obtain a resin composition; and an extrusion step of extruding the resin composition from the discharge section. Regarding the method.

The present invention has made it possible to provide packaging materials with excellent lamination strength, oxygen barrier properties, and recyclability.

The embodiments of the present invention will be described in detail below, but the described embodiments or explanations of requirements are examples of the embodiments of the present invention, and the present invention is not limited to these contents unless it exceeds the gist thereof. .

[Packaging material]
The packaging material of the present invention is a packaging material having a base material 1, a barrier layer, a printed layer, and a base material 2, wherein the packaging material contains 80% by mass or more of a polyolefin resin in the total mass of the packaging material. The present invention relates to a packaging material, wherein the barrier layer contains a polyvinyl alcohol-based resin, and the printing layer contains a polyvinyl acetal-based resin. Even if the packaging material is one in which the base material 1, the barrier layer, the printed layer, and the base material 2 are laminated in this order, the packaging material may be one in which the base material 1, the printed layer, the barrier layer, and the base material 2 are laminated in this order. It may be something. In addition, in the step of manufacturing the laminate, layers may be sequentially formed on the base material 1, or the base material 1 may have layers such as a printed layer and a barrier layer, and the base material 1 may have a layer such as a printed layer and a barrier layer. It may be laminated with the base material 2.
The packaging material of the present invention is suitable for material recycling of polyolefin packaging materials having barrier properties. It maintains the performance required as a packaging material, and when recycled, it can be melted and pelletized as it is, for example. Although it is not essential to perform cleaning of contents and dirt or separation of layers other than the polyolefin resin before the melting process, it is not excluded.

When the barrier layer contains a polyvinyl alcohol-based resin, oxygen barrier properties are improved. In addition, since the polyvinyl alcohol resin has high solubility in water, the barrier layer dissolves when immersed in water, resulting in good separation of the base material 1 and the base material 2. Furthermore, by including the polyvinyl acetal resin in the printing layer and the polyvinyl alcohol resin in the barrier layer, the adhesion between the printing layer and the barrier layer is improved, so that the laminate strength is improved. Furthermore, by including 80% by mass or more of the polyolefin resin in the total mass of the packaging material, the recycled polyolefin after material recycling has less foreign matter and burntness, resulting in good recyclability.

In the present invention, each layer such as a printed layer is simply referred to as a printed layer when actually multiple layers are laminated in contact, such as a first printed layer and a second printed layer, respectively. . Examples of the form of the base material 1 and the base material 2 include a film-like or sheet-like base material, a sealant, a resin film formed by melt coating, and the like. Among these, film-like or sheet-like base materials and sealants are preferred. A laminate laminate is preferred as an embodiment of the packaging material.

The laminate refers to a laminate manufactured by laminating resin layers, and may include a base material 1, a barrier layer, a printed layer, and a base material 2. In one embodiment, the laminate may have a structure in which a base material 1, a printing layer, a barrier layer, and a base material 2 are bonded together.

[Recycled polyolefin]
The packaging material of the present invention is preferably used for recycled polyolefin, which is a so-called material recycling application. Recycled polyolefin is a plastic material that is made from packaging materials and can be used as a molding material. Therefore, in many cases, recycled polyolefin does not consist of 100% by mass of polyolefin resin, but in order to perform its function as a plastic material (hereinafter also referred to as recyclability), the packaging material must contain polyolefin resin. Contains 80% by mass or more of the total mass of the packaging material. The content is more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. When the content is within the above range, the uniformity of the recycled polyolefin is improved, resulting in good recyclability.
Furthermore, if a step is included in which components other than the polyfin resin constituting the packaging material, such as the barrier layer and the printing layer, are removed (hereinafter also referred to as separation) from the polyfin resin as much as possible, the recyclability is further improved. Become.

Preferably, the polyolefin is polypropylene and/or polyethylene. More preferably, the polypropylene is a copolymer with ethylene and/or butene.

Specifically, the configuration of the packaging material can be exemplified by the following configurations, but is not limited to these. Note that in the configuration representations (1) to (9) below, "/" means the boundary between each layer. The adhesive layer is not limited to adhesives used in dry lamination and non-sol lamination, which are conventionally known methods, but also includes polyolefin resin or other thermoplastic resin layers in extrusion lamination. . In addition, the names of each layer are functional in terms of usage, and the base material, sealant, thermoplastic resin layer, heat sealing agent layer, and intermediate base material are distinguished from each other from a material perspective unless they are in direct contact. Sometimes I can't.
(1) Base material/Print layer/Barrier layer/Adhesive layer/Sealant (2) Base material/Print layer/Barrier layer/Adhesive layer/Intermediate base material/Adhesive layer/Sealant (3) Base material/Print layer /Barrier layer/Adhesive layer/First intermediate base material/Adhesive layer/Second intermediate base material/Adhesive layer/Sealant (4) Base material/Printed layer/Barrier layer/Thermoplastic resin layer (5) Base material / Print layer / Barrier layer / (AC agent layer) / Thermoplastic resin layer / Sealant (6) Base material / Print layer / Barrier layer / (AC agent layer) / Thermoplastic resin layer / Intermediate base material / (AC agent layer)/thermoplastic resin layer/sealant (7) base material/printed layer/barrier layer/adhesive layer/intermediate base material/(AC agent layer)/thermoplastic resin layer/sealant (8) base material/printed layer /Barrier layer/(AC agent layer)/Thermoplastic resin layer/Intermediate base material/Adhesive layer/Sealant (9) Base material/Barrier layer/Printing/Adhesive layer/Sealant (10) Base material/Barrier layer/Printing /Adhesive layer/Intermediate base material/Adhesive layer/Sealant (11) base material/Barrier layer/Printing/Adhesive layer/First intermediate base material/Adhesive layer/Second intermediate base material/Adhesive layer / Sealant (12) Base material / Barrier layer / Printing / Thermoplastic resin layer (13) Base material / Barrier layer / Printing / (AC agent layer) / Thermoplastic resin layer / Sealant (14) Base material / Barrier layer / Printing /(AC agent layer)/Thermoplastic resin layer/Intermediate base material/(AC agent layer)/Thermoplastic resin layer/Sealant (15) Base material/Barrier layer/Printing/Adhesive layer/Intermediate base material/(AC agent Layer)/Thermoplastic resin layer/Sealant (16) Base material/Barrier layer/Printed layer/(AC agent layer)/Thermoplastic resin layer/Intermediate base material/Adhesive layer/Sealant However, the embodiment of the present invention applies to these layers. Not limited.

In the above configuration, the AC agent layer represents an anchor coating agent layer, and is used to improve the adhesiveness between the base material or the printing layer and the thermoplastic resin layer. Note that the above (AC agent layer) may or may not be present. Moreover, (AC agent layer) is one embodiment of an adhesive layer.

<Aspects of packaging material>
When the packaging material includes a base material and a sealant, the packaging material preferably has the following configuration.
(1) In this case, both the base material and the sealant contain polypropylene, the heating melting temperature of the packaging material is preferably 150 to 250°C, more preferably 180 to 230°C, and even more preferably 190 to 220°C. When it is within the above range, the film has good foreign matter.
(2) In this case, the base material contains polypropylene and the sealant contains polyethylene, the heating melting temperature of the packaging material is preferably 140 to 240°C, more preferably 170 to 220°C, and even more preferably 180 to 210°C. When it is within the above range, the film has good foreign matter.
(3) In this case, where both the base material and the sealant contain polyethylene, the heating and melting temperature of the packaging material is preferably 130 to 230°C, more preferably 160 to 210°C, and even more preferably 170 to 200°C. When it is within the above range, the film has good foreign matter.

[Base material 1]
The base material 1 in the packaging material is preferably a plastic base material mainly containing polyolefin resin as a raw material. For use in packaging, film or sheet form is preferred. Base materials that mainly contain polyolefin resins have higher resistance to alkaline aqueous solutions and heat during the molding process than ester base materials, and are less likely to undergo thermal decomposition or hydrolysis, making it difficult to maintain a high molecular weight. can.
Furthermore, as plastic base materials mainly containing the polyolefin resin, for example, biaxially oriented polypropylene (OPP), unoriented polypropylene (CPP), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene ( Preferred examples include polyethylene such as MDPE), high-density polyethylene (HDPE), acid-modified polyethylene, acid-modified polypropylene, copolymerized polypropylene, and films laminated with these. The thickness of the base material is not particularly limited, and in consideration of processability into packaging containers, it is preferably 5 μm or more and 150 μm or less, more preferably 10 μm or more and 70 μm or less. Further, a film having heat-sealing properties is suitably used, such as CPP and heat-sealing OPP.

The base material mainly containing polyolefin resin may be simply laminated plastic base materials, or base materials different from the plastic base material may be laminated via adhesion or the like. "A base material different from a plastic base material" includes a film having different properties, and the type thereof does not matter. Furthermore, in the case of a laminated base material, it may include an adhesive layer. The laminating method is not particularly limited, and conventionally known methods such as coextrusion, heat fusion, and pressure bonding via an adhesive layer can be used.

The base material may include (coated or kneaded) additives such as antistatic agents, antifogging agents, and ultraviolet light inhibitors, or may include an easily adhesive coating layer (for example, a layer containing polyvinyl alcohol and its derivatives). Preferably, the surface of the base material is subjected to corona treatment or low-temperature plasma treatment. The above additions and processing are also used to improve the wettability of printing inks and other coating agents, and to provide specific functionality to the film.For example, by preventing the packaging material from fogging due to moisture, It is also suitably used to provide packaging materials with excellent visibility of contents.

[Printing layer]
The printing layer of the packaging material contains polyvinyl acetal resin, and may contain arbitrary pictures, patterns, characters, and symbols for the purpose of decoration or adding beauty; indicating the contents, expiration date, and manufacturer or seller. It can be a layer for displaying etc.
The printing layer may be a solid printing layer that does not have a picture, a pattern, a character, a symbol, or the like. The method for forming the printing layer is not particularly limited, and printing ink can be used to form the printing layer. Further, the printed layer may have a single layer structure or a multilayer structure, and may be printed on the surface layer. The thickness of the printed layer is preferably 0.1 to 12 g/m ² , more preferably 0.5 to 6 g/m ² , and even more preferably 1 to 3 g/m ² .

(Polyvinyl acetal resin)
In the present invention, the polyvinyl acetal resin is acetalized by reacting polyvinyl alcohol with an aldehyde such as butyraldehyde, and preferably contains a vinyl alcohol unit, a vinyl acetate unit, and an acetal ring unit. Polyvinyl acetal resin has a role as a binder resin. In the acetalization reaction, known aldehydes such as formaldehyde and acetaldehyde can be used, and two or more types of aldehydes can also be used.

Examples of the polyvinyl acetal resin include polyvinyl formal, polyvinyl acetal, and polyvinyl butyral, with polyvinyl butyral being preferred.

The acetal ring content of the polyvinyl acetal resin is preferably 60 to 90% by mass based on 100% by mass of the polyvinyl acetal resin. When it is within the above range, adhesion is improved and lamination strength is improved.

The vinyl alcohol unit content of the polyvinyl acetal resin is preferably 5 to 30% by mass, more preferably 15 to 25% by mass based on 100% by mass of the polyvinyl acetal resin. When it is within the above range, adhesion is improved, and lamination strength and separability are improved.

The vinyl acetate unit content of the polyvinyl acetal resin is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass based on 100% by mass of the polyvinyl acetal resin. When it is within the above range, adhesion is improved and lamination strength is improved.

The weight average molecular weight of the polyvinyl acetal resin is preferably 25,000 to 200,000, more preferably 40,000 to 150,000, and even more preferably 70,000 to 120,000. When it is within the above range, the lamination strength and separability will be good.

The glass transition point of the polyvinyl acetal resin is preferably 50 to 80°C, more preferably 60 to 75°C. When it is within the above range, the lamination strength will be good.

Commercially available polyvinyl acetal resins include Mobital series (manufactured by Kuraray Co., Ltd., polyvinyl butyral resin), S-LEC KX series (manufactured by Sekisui Chemical Co., Ltd., polyvinyl acetal resin), and Vinylec series (manufactured by JNC Co., Ltd., polyvinyl formal). can be used.

The printing layer can contain resins other than polyvinyl acetal resin, and specific examples include urethane resin, cellulose resin, polyamide resin, rosin resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, and vinyl chloride. - Vinyl acetate copolymer resins, acrylic resins, styrene resins, styrene-maleic acid copolymer resins, polyester resins, and the like. These resins can be used alone or in combination of two or more. Among these, it is preferable to contain one or more resins selected from the group consisting of resins other than vinyl chloride-vinyl acetate copolymer resins, and it is more preferable to contain at least a urethane resin.

(Urethane resin)
The urethane resin used in the present invention may be any resin having a urethane bond, and can be appropriately selected from known resins. As the urethane resin, for example, a urethane resin made of a polyol and a polyisocyanate; a urethane urea resin obtained by reacting a urethane prepolymer of a terminal isocyanate made of a polyol and a polyisocyanate with a chain extender such as a polyamine; ; are mentioned and suitably used. Examples of methods for producing such urethane resin include methods described in JP-A No. 2013-256551, JP-A No. 2018-127545, and JP-A No. 2013-213109.

The weight average molecular weight of the urethane resin is preferably 10,000 to 100,000, more preferably 20,000 to 85,000, and even more preferably 30,000 to 70,000. When it is within the above range, the lamination strength will be good.

The glass transition point of the urethane resin is preferably -80 to 20°C, more preferably -60 to 0°C, even more preferably -40 to -5°C. When it is within the above range, the lamination strength will be good.

The amine value of the urethane resin is preferably 0.5 to 20 mgKOH/g, more preferably 1 to 15 mgKOH/g. When it is within the above range, the lamination strength will be good.

The hydroxyl value of the urethane resin is preferably 0.5 to 30 mgKOH/g, more preferably 1 to 20 mgKOH/g. When it is within the above range, the separability becomes good.

When the printing layer contains a urethane resin, the mass ratio of the polyvinyl acetal resin to the polyurethane resin is preferably 1:99 to 85:15, more preferably 5:95 to 70:30. , more preferably from 12:88 to 40:60, particularly preferably from 15:85 to 25:75. When it is within the above range, the lamination strength will be good.

(polyol)
Examples of the polyols include polyester polyols, polyether polyols, polylactone polyols, polycarbonate polyols, polyolefin polyols, castor oil polyols, hydrogenated castor oil polyols, dimer diols, and hydrogenated dimer diols. The polyol is preferably a polyether polyol or a polyester polyol.

The number average molecular weight of the polyol is preferably from 500 to 5,000, more preferably from 1,000 to 3,000.

The mass ratio of branched diols and linear diols in the diols constituting the polyester polyol (mass of branched diols: mass of linear diols) is preferably 10:90 to 90:10, and 20: The ratio is more preferably 80 to 80:20, and even more preferably 30:70 to 70:30.

As mentioned above, the urethane resin preferably contains a structural unit derived from at least one polyol selected from the group consisting of polyether polyols and polyester polyols.
The content of structural units derived from at least one polyol selected from the group consisting of polyether polyols and polyester polyols is preferably 5 to 95% by mass, and 20 to 90% by mass, based on the solid mass of the urethane resin. It is more preferably 30% to 85% by mass, and even more preferably 30 to 85% by mass.

The content of the structural units derived from the polyester polyol is preferably 40% by mass or more, preferably 50% by mass or more, and preferably 55% by mass or more, based on the solid mass of the urethane resin. It is preferably 65 to 100% by weight, particularly preferably 65 to 100% by weight. At the above content rate, the laminate strength will be good.

<Chlorine content of resin contained in printing layer>
The chlorine content of the resin contained in the printed layer is the content of chlorine atoms (% by mass) based on the mass of the resin contained in the printed layer. The resin contained in the printing layer preferably has a chlorine content of 0 to 5% by mass, more preferably 0 to 3% by mass, and even more preferably 0 to 2% by mass. When it is within the above range, chlorine generation can be suppressed in the heating melt-kneading step in the [method for producing recycled polyolefin] described below. The origin of the chlorine contained in the resin contained in the printing layer may be that the ethylenically unsaturated monomer used itself contains chlorine atoms, or that a compound containing chlorine atoms is mixed in during the manufacturing process.

The chlorine content can be measured using known methods such as ion chromatography (IC) and ICP mass spectrometry (ICP-MS). Examples of measuring instruments include LC-20ADsp manufactured by Shimadzu Corporation for IC, and Agilent 7700x manufactured by Agilent Technologies for ICP-MS. Further, the chlorine content of the printed layer can be simply calculated from the chlorine content of each raw material constituting the printed layer using the following formula. The same applies to each other layer.
Formula: Chlorine content (%) in the total solid mass of the resin contained in the printing layer = Mass of chlorine in the total solid mass of the resin contained in the printing layer / Total solid mass of the resin contained in the printing layer (%)
Formula: Chlorine content (%) in the total mass of solids in the printing layer = Mass of chlorine in the total mass of solids in the printing layer / Total mass of solids in the printing layer (%)

In the present invention, the chlorine content is preferably measured in accordance with JIS K0127 (2013). In this measurement method, a sample that has been pretreated using a combustion method is quantified using an ion chromatography method.

《Colorant》
The printing ink used for forming the printing layer in the present invention can contain a colorant.
The coloring agent is preferably a pigment, and the pigment can be either an organic pigment or an inorganic pigment, but one type of coloring agent such as a pigment may be used alone, or two or more types may be used in combination. You may. In consideration of quality deterioration due to coloring of the recycled polyolefin, the content of the colorant in the total mass of the printed layer is preferably 30% by mass or less, more preferably 25% by mass or less, and 23% by mass or less. It is even more preferable that there be.

(organic pigment)
Examples of the above-mentioned organic pigments include, but are not limited to, soluble azo, insoluble azo, azo, phthalocyanine, halogenated phthalocyanine, anthraquinone, anthurone, dianthraquinonyl, and anthrapyrimidine. , perylene series, perinone series, quinacridone series, thioindigo series, dioxazine series, isoindolinone series, quinophthalone series, azomethine azo series, flavanthrone series, diketopyrrolopyrrole series, isoindoline series, indanthrone series, carbon black series, etc. Pigments include: Also, for example, Carmine 6B, Lake Red C, Permanent Red 2B, Disazo Yellow, Pyrazolone Orange, Carmine FB, Chromophthal Yellow, Chromophthal Red, Phthalocyanine Blue, Phthalocyanine Green, Dioxazine Violet, Quinacridone Magenta, Quinacridone Red, Indance. Examples include lon blue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, and daylight fluorescent pigments.

(Inorganic pigment)
Inorganic pigments include titanium oxide, zinc oxide, zinc sulfide, chromium oxide, aluminum particles, mica, bronze powder, chrome vermilion, chrome yellow, cadmium yellow, cadmium red, ultramarine blue, navy blue, red iron oxide, yellow iron oxide, Examples include iron black, titanium oxide, zinc oxide, silica, barium sulfate, kaolin clay, calcium carbonate, magnesium carbonate, etc. Aluminum can be of leafing type or non-leafing type, but non-leafing type is preferable.

"Additive"
The printing ink used for forming the printing layer in the present invention may optionally contain an antifoaming agent, an aromatic agent, a flame retardant, a hydrocarbon wax, a thickener, a leveling agent, a dispersant, a curing agent, a silane coupling agent, It may contain known additives such as plasticizers, infrared absorbers, and ultraviolet absorbers, and preferably contains at least one selected from the group consisting of hydrocarbon waxes and dispersants.

<Production method of printing ink>
The printing ink used to form the printing layer is made by, for example, dispersing a pigment with a resin or the like in an organic solvent using a dispersion machine, and then mixing the resulting pigment dispersion with a resin, various additives, an organic solvent, etc. Can be manufactured. As the dispersing machine, commonly used ones such as roller mills, ball mills, pebble mills, attritors, and sand mills can be used.

<Formation of printing layer>
The printed layer can be formed, for example, by printing on the base material using printing ink and then removing volatile components. As a printing method, a gravure printing method or a flexographic printing method is suitable. For example, the material is diluted with a diluting solvent to a viscosity and concentration suitable for gravure printing, and then supplied alone or in a mixture to each printing unit and applied. . Thereafter, a printed layer can be obtained by fixing the film by drying in an oven or the like.

[Barrier layer]
The barrier layer in this application exists for the purpose of imparting oxygen barrier properties to the packaging material, and the barrier layer contains a polyvinyl alcohol resin. Although any known form can be used as the form of the barrier layer, a barrier coat layer is preferred. When the packaging material has a barrier coat layer as a barrier layer, the barrier coat layer is formed from a barrier coat agent.

The coating amount of the barrier layer is preferably 0.5 to 5 g/m ² , more preferably 0.7 to 2.8, and even more preferably 1.3 to 2. When it is within the above range, oxygen barrier properties and recyclability will be good.

(Polyvinyl alcohol resin)
The polyvinyl alcohol resin used in the present invention may be any resin as long as it has a vinyl alcohol unit, and may further contain a structural unit derived from ethylene.
Examples include polyvinyl alcohol resin and ethylene-vinyl alcohol copolymer resin, with ethylene-vinyl alcohol copolymer resin being preferred.

The content of structural units derived from ethylene in the polyvinyl alcohol resin is preferably 1 to 40 mol%, more preferably 3 to 20 mol%, and even more preferably 5 to 15 mol%. When it is within the above range, the laminate strength and oxygen barrier properties will be good.

The polyvinyl alcohol resin can have a modifying group, and examples include, but are not limited to, known modifying groups such as carbonyl modification and silicon modification.

The polyvinyl alcohol resin can be crosslinked with a crosslinking agent, and the crosslinking agents used include known crosslinking such as isocyanate type, epoxy type, melamine type, oxazoline type, and silane coupling type. Oxazoline type and silane coupling type are preferred.

The degree of saponification of the polyvinyl alcohol resin is expressed by the following formula, and is preferably 80 mol% or more, more preferably 90 mol%, and preferably 95 mol%. When it is within the above range, the oxygen barrier properties will be good.

Formula: Saponification degree: (number of hydroxyl groups) / {(number of hydroxyl groups) + (number of acetic acid groups)} x 100 [mol%]

The degree of polymerization of the polyvinyl alcohol resin is preferably from 100 to 3,000, more preferably from 500 to 2,400. When it is within the above range, the solubility in water is improved and the separability becomes good.

As the polyvinyl alcohol resin, Kuraray Poval R series (manufactured by Kuraray Co., Ltd., polyvinyl alcohol resin), Kuraray Eval L104B, F104B (manufactured by Kuraray Co., Ltd., ethylene-vinyl alcohol copolymer resin), etc. can be used.

The barrier layer can contain resins other than polyvinyl alcohol resin, and specific examples include polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, acrylic resin, and the like. These resins can be used alone or in combination of two or more.

(Inorganic layered filler)
Preferably, the barrier layer contains an inorganic layered filler. The term "inorganic layered filler" as used herein refers to an inorganic filler in which unit crystal layers overlap to form a layered structure, and particularly preferred is one that swells and cleaves in a solvent.

Preferred examples of inorganic layered fillers include montmorillonite, beidellite, saponite, hectorite, sauconite, vermiculite, mica, paragonite, lepidolite, margarite, clintonite, anandite, chlorite, donbasite, sudoite, cookaite, clinochlore, and chamosite. , nimite, tetrasilylic mica, talc, pyrophyllite, nacrite, kaolinite, halloysite, chrysotile, sodium taeniolite, xanthophyllite, antigorite, dickite, hydrotalcite, and kaolin, montmorillonite, mica. Preferably, it is montmorillonite, and more preferably montmorillonite.

These inorganic layered compounds may be naturally occurring, artificially synthesized or modified, or may be treated with an organic substance such as an onium salt.

The content of the inorganic layered filler in the barrier layer is preferably 1 to 40% by mass, more preferably 10 to 35% by mass, and 20 to 30% by mass based on 100% by mass of the barrier layer. is even more preferable.

(montmorillonite)
Montmorillonite used in the present invention is represented by the following formula, and can be obtained by refining naturally occurring montmorillonite.
M _a Si ₄ (Al _2-a Mg _a ) O ₁₀ (OH) ₂ ·nH ₂ O
(In the formula, M represents a sodium cation, and a is 0.25 to 0.60. Also, the number of water molecules bonded to the ion-exchangeable cation between the layers is determined by the conditions such as the cation type and humidity. (It is expressed as nH ₂ O in the formula because it can change depending on the
In addition, montmorillonite includes isotype ion substituted products of magnesian montmorillonite, iron montmorillonite, and iron magnesian montmorillonite represented by the following formula group, and these may be used.
M _a Si ₄ (Al _1.67-a Mg _0.5+a ) O ₁₀ (OH) ₂ ·nH ₂ O
M _a Si ₄ (Fe _2-a3 + _Mga ) O ₁₀ (OH) ₂ ·nH ₂ O
M _a Si ₄ (Fe _1.67-a3 + Mg _0.5+a ) O ₁₀ (OH) ₂・nH ₂ O
(In the formula, M represents a sodium cation, and a is 0.25 to 0.60.)

Montmorillonite usually has cations between its layers, but the content ratio varies depending on the production area. Examples of the above ions include inorganic cations such as sodium ions, calcium ions, magnesium ions, and potassium ions, and organic cations such as quaternary ammonium ions.From the viewpoint of affinity for water, inorganic cations are preferable. , sodium ions and calcium ions are more preferred. Moreover, it is preferable to use montmorillonite purified by water treatment.

The volume average particle thickness of montmorillonite is preferably 0.05 to 30 nm, more preferably 0.1 to 10 nm, and even more preferably 0.5 to 3 nm. In addition, the volume average major diameter of the particles of montmorillonite is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm, and even more preferably 0.1 to 1 μm. In addition, the volume average particle aspect ratio of montmorillonite is preferably 10 to 2,000, more preferably 100 to 1,000, and even more preferably 300 to 700.
In the present invention, the particle thickness, particle major axis, and particle aspect ratio of montmorillonite can be measured using an atomic force microscope (AFM).

As the montmorillonite, commercially available products such as Kunipia-F and Kunipia-G (manufactured by Kunimine Kogyo Co., Ltd.) can be used.

(Kaolin)
The kaolin used in the present invention has kaolinite (Al ₂ O _{3 .2SiO} 2 .H ₂ O) or halloysite Al ₂ O ₃ .2SiO ₂ .2H ₂ O as its main component, and even if it is a natural product, it cannot be synthesized. It may be a product. Further, depending on the manufacturing method, there are dry kaolin, wet kaolin, calcined kaolin, etc., but the method is not limited to these.

The volume average particle diameter of kaolin is preferably 1 to 100 μm, more preferably 3 to 50 μm, and even more preferably 5 to 20 μm, from the viewpoint of oxygen barrier properties. Further, the volume average aspect ratio of kaolin is preferably 10 to 1000, more preferably 30 to 500, and even more preferably 50 to 200.
In the present invention, the particle size of kaolin can be measured by laser analysis/scattering method, and the aspect ratio can be measured by a scanning electron microscope (SEM).

Commercially available products such as Varisurf HX (manufactured by Imerys), NN kaolin clay, and ST kaolin clay (manufactured by Takehara Chemical Industry Co., Ltd.) can be used.

(mica)
The mica used in the present invention can be either natural mica or synthetic mica. Natural mica is a scaly base material obtained by crushing the mineral mica (mica), and the particle size and aspect ratio can be controlled by mechanical crushing or cleavage by calcination. Synthetic mica is synthesized by heating industrial raw materials such as SiO ₂ , MgO, Al ₂ O ₃ , K ₂ SiF ₆ , Na ₂ SiF ₆ , etc., melting them at a high temperature of about 1500°C, and cooling and crystallizing them. Compared to natural mica, it has fewer impurities and is more uniform in size and thickness. Specifically, fluorine phlogopite (KMg ₃ AlSi ₃ O10F ₂ ), potassium tetrasilicon mica (KMg ₂₅ AlSi ₄ O10F ₂ ), sodium tetrasilicon mica (NaMg ₂₅ AlSi ₄ O ₁₀ F ₂ ), and Na teniolite (NaMg ₂ LiSi ₄ O10F ₂ ), LiNa teniolite (LiMg ₂ LiSi ₄ O ₁₀ F ₂ ), and the like are known. From the viewpoint of dispersibility, synthetic mica that is easily cleaved by intercalation is preferred.

The volume average particle diameter of mica is preferably 30 μm or less, more preferably 1 to 25 μm, and even more preferably 5 to 15 μm, from the viewpoint of printability and oxygen barrier properties. The volume average aspect ratio of mica is preferably 30 to 200, more preferably 70 to 170, and even more preferably 100 to 150.
In the present invention, the particle size of mica can be measured by laser analysis/scattering method, and the aspect ratio can be measured by a scanning electron microscope (SEM).

As mica, commercial products such as Mica Powder TM series, Mica Powder NCF series (manufactured by Yamaguchi Mica Co., Ltd.), L60M, and L100M (manufactured by Seishin Enterprise Co., Ltd.) can be used.

The barrier coating agent can be added to the coating agent by adding each of the above-mentioned components alone or in combination, and further adding an isocyanate compound, a silane coupling agent, a dispersing agent, a stabilizing agent, etc. to the extent that the barrier properties of the coating agent are not impaired. Known additives such as a coloring agent, a viscosity modifier, and a coloring agent can be added.

<Formation of barrier layer>
The barrier layer can be formed, for example, by printing a barrier coating agent on a substrate and then removing volatile components. Examples of the printing method include conventionally known methods such as gravure printing, flexo printing, dipping, roll coating, screen printing, and spraying, but gravure printing is preferable. It is diluted with a diluting solvent to the desired viscosity and consistency, and fed alone or in a mixture to each printing unit and applied. Thereafter, a printed layer can be obtained by fixing the film by drying in an oven or the like.

The packaging material in the present application may further include an adhesive layer and an intermediate base material layer as long as the polyolefin content in the packaging material is 80% or more by mass.

[Layers other than base material 1, printing layer, barrier layer, and base material 2]
<Adhesive layer>
The packaging material used in the present invention may include an adhesive layer for the purpose of bonding each layer. The adhesive layer is not particularly limited, and may include dry laminating adhesives and non-sol laminating adhesives such as olefin adhesives, acrylic adhesives, ethylene-vinyl acetate copolymer adhesives, and reactive urethane adhesives. Preferred examples include imine-based anchor coating agents, butadiene-based anchor coating agents, isocyanate-based anchor coating agents, and thermoplastic resins used in extrusion laminates. In addition, it is preferable that the adhesive layer is a reaction product of a reactive urethane adhesive consisting of polyisocyanate and polyol.

The method for adhering (also referred to as laminating) each layer is not particularly limited, and conventionally known methods such as extrusion lamination, dry lamination, and non-sol lamination may be used.

<Intermediate base material layer>
In the present application, the intermediate base material layer exists for the purpose of improving the rigidity of the packaging material. A specific example of the intermediate base material layer is preferably a plastic base material mainly containing polyolefin resin as a raw material, similarly to the base material layer. For example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), ethylene-vinyl acetate copolymer, propylene homopolymer, ethylene-propylene copolymer Examples include polyolefin resins such as polymers. Alternatively, a composite base material produced by a coextrusion method may be used. Furthermore, it is more preferable that the intermediate base material is the same type (same) material as the base material and the sealant. Examples of similar (same) materials include combinations of polypropylenes, polyethylenes, and the like.

[Base material 2]
The base material 2 may be the same as or different from the base material 1, for example, biaxially oriented polypropylene (OPP), unoriented polypropylene (CPP), low density polyethylene (LDPE), linear low density polyethylene (LLDPE). Preferred examples include polyethylene such as , medium density polyethylene (MDPE), and high density polyethylene (HDPE), acid-modified polyethylene, acid-modified polypropylene, and copolymerized polypropylene.

The thickness of the base material 2 is not particularly limited, but from the viewpoint of processability during production of packaging containers, it is preferably 5 to 150 μm, more preferably 10 to 70 μm. In one embodiment, among polyolefin resins, those having heat sealability can be suitably used. Examples of this include corona-treated biaxially oriented polypropylene (OPP) film, high-density polyethylene film (HDPE), unoriented polypropylene (CPP) film, linear low-density polyethylene (LLDPE) film, Examples include PE resin film.

<Chlorine content of packaging material>
In the packaging material, the chlorine content is preferably 0.4% by mass or less, more preferably 0.2% by mass or less, and 0.1% by mass or less based on the total mass of the packaging material. is even more preferable.

<Melt mass flow rate (MFR) of packaging materials>
The melt mass flow rate (MFR) of the packaging material in the present invention is carried out under the conditions of a sample having the highest content by crushing it into pieces with a side length of 5 mm to 10 mm. The melt mass flow rate in the present invention is a value measured in accordance with JISK7210. The MFR of the packaging material is preferably 0.5 to 15 g/10 minutes, more preferably 1.0 to 14 g/10 minutes, and still more preferably 3 to 13 g/10 minutes. When the content is within the above range, the fluidity in the heating melt-kneading process is improved, so that film burnability is improved.

<Content of pigment and inorganic layered filler in packaging material>
The content of pigments and inorganic layered fillers in the packaging material is preferably 5% by mass or less, more preferably 3% by mass or less, and 1.5% by mass or less based on 100% by mass of the packaging material. More preferably. When it is within the above range, the film has good foreign matter.

[Production method of recycled polyolefin]
In one embodiment of the invention, recycled polyolefin can be obtained from the packaging material using an extrusion device equipped with a first screw and a discharge section.
Specifically, the steps for obtaining recycled polyolefin include a heating melt-kneading step in which a packaging material and an antioxidant are heated and melt-kneaded to form a resin composition, and an extrusion step in which the obtained resin composition is extruded. Furthermore, it is preferable to include a cooling step of cooling the extruded recycled polyolefin. The shape of the recycled polyolefin is not particularly limited, and examples thereof include rods, particles, cubes, rectangular parallelepipeds, and irregular shapes.

In the present application, from the viewpoint of handling of the packaging material, it is preferable to include a crushing step of crushing the packaging material before the heating melt-kneading step. Further, from the viewpoint of removing foreign substances such as dust and dirt, it is preferable to include a washing step of washing the packaging material before the heating melt-kneading step. Furthermore, from the viewpoint of moisture removal, it is preferable to include a dehydrating and drying step of dehydrating and drying the packaging material before the heating melt-kneading step. In addition, it is preferable to include means for adding additives in the heating melt-kneading step. Further, from the viewpoint of removing foreign matter, it is preferable that the discharge section of the extrusion device is provided with a foreign matter separating device. Furthermore, from the viewpoint of handling of the recycled polyolefin, it is preferable to include a pelletizing step of shredding the extruded recycled polyolefin after or simultaneously with the cooling step.

<Heating melt kneading process>
The heating melt-kneading process is a process of heating, melting and kneading the packaging material using an extrusion device equipped with a first screw, and through this process, the packaging material is heated and melted and further kneaded by the first screw. This changes from a separate packaging material and antioxidant to a continuous phase resin composition. The higher the uniformity of the resin composition, the better the foreign matter in the film immediately after the recycled polyolefin and the foreign matter in the film over time.

The heating melting temperature is preferably 160°C to 260°C, more preferably 170°C to 250°C, and even more preferably 180°C to 240°C. When the content is within the above range, the uniformity of the recycled polyolefin and the low heat history can be achieved at the same time, so that film foreign substances and film burns are prevented.

The rotation speed of the first screw is 50 to 900 rpm, preferably 80 rpm to 850 rpm, and more preferably 100 rpm to 600 rpm. Within the above range, the uniformity of the recycled polyolefin and the short residence time in the extrusion device can be achieved, so that film foreign matter and film burns are prevented. Note that the screw rotation speed of 50 to 900 rpm corresponds to a shear rate of 222 to 4004 sec ^-1 . The shear rate was calculated using the following formula under the conditions of Examples described below.
Formula: (pi) x (screw diameter) x (screw rotation speed) / {(60 x (minimum gap distance between cylinder inner wall and screw))}
・Screw diameter: 34mm
・Minimum gap distance between cylinder inner wall and screw: 0.4mm

The residence time of the resin composition in the extrusion device is preferably 10 to 120 seconds, more preferably 15 to 80 seconds, and particularly preferably 20 to 40 seconds. When it is within the above range, the heating time and kneading efficiency become good, so that a recycled polyolefin with excellent film foreign matter and film burns can be obtained.

《Extrusion device equipped with a first screw》
The extrusion device used in the present invention is equipped with a first screw. The extrusion device is a device capable of melting and molding commonly used thermoplastic resins, and for example, a known extrusion device described in JP 2017-148997A can be used.
Specifically, a first supply port that supplies the material, a heating melt kneading section that heats and melts and kneads the material such as a thermoplastic resin supplied from the first supply port, and a heating melt kneading section that heats It has a discharge part that discharges the melt-kneaded thermoplastic resin.
As the first screw rotates, the material is melted by shear heat or heating by an electric heater, etc., and the molten material is kneaded by the rotation of the first screw. Examples of the extrusion apparatus include a twin-screw extruder, a single-screw extruder, and a rotor-type twin-screw kneader, and from the viewpoint of kneading efficiency, a twin-screw extruder and a rotor-type twin-screw kneader are preferable.

<Method of adding additives>
In the present invention, known additives such as antioxidants and compatibilizers can be added. As a method for adding additives, the packaging material to which the additives have been added is supplied from the first supply port in the heating melt-kneading process, or an extrusion device equipped with the second supply port and second screw described below. A preferred example is to add the additive using. The extrusion device can be made by connecting barrels, so that one or more of the barrels can be provided with a second feed port and a second screw, and the position of the second feed port and the second screw can be can be located anywhere in the extrusion device. The additives added from the second supply port are mixed with the resin composition that has been introduced through the first supply port and heated and melted and kneaded while being kneaded by the second screw.

"Additive"
Examples of known additives other than antioxidants include antioxidants, compatibilizers, lubricants, weathering stabilizers, plasticizers, and antistatic agents. It is preferable that an antioxidant is included from the viewpoint of improving film tanning.

(Antioxidant)
As the antioxidant, known antioxidants such as phenol-based, phosphoric acid-based, sulfur-based, and amine-based antioxidants can be used, but phenol-based and phosphoric acid-based antioxidants are preferable. The mass ratio of the antioxidant to the packaging material is preferably 0.01:99.99 to 3:97, preferably 0.05:99.95 to 1:99, and 0.01:99.99 to 3:97, preferably 0.05:99.95 to 1:99. More preferably, the ratio is 1:99.9 to 0.5:99.5. If it is within the above range, film burn will be good.

(phenolic antioxidant)
Examples of antioxidants used in the present invention include monophenol-based, bisphenol-based, trisphenol-based, tetraphenol-based, polyphenol-based, thiobisphenol-based, etc. , is preferably a tetraphenol type, more preferably a tetraphenol type.

As the phenolic antioxidant, Irganox 1010, Irganox 1076, Irganox 245 (manufactured by BASF), etc. can be used.

(Phosphoric acid antioxidant)
The antioxidants used in the present invention include monononyl, dinonyl, trinonyl, allyl, alkylaryl, monoalkyl, dialkyl, trialkyl, and dioxa antioxidants, which have a large anti-scorch effect. , trinonyl type, allyl type, alkylaryl type, trialkyl type, and dioxa type, and more preferably dioxa type.

As the phosphoric acid antioxidant, Irgafos 168 (manufactured by BASF), ADK STAB PEP-36 (manufactured by ADEKA), etc. can be used.

(Compatibilizer)
The compatibilizer has the role of making it easier for the pigment and resin derived from the printing layer to mix with the plastic. The compatibilizer preferably contains a polyolefin copolymer, and examples of the polyolefin copolymer include a polyolefin-styrene copolymer, a polyolefin-acrylic copolymer, a polyolefin-acrylonitrile copolymer, and (anhydrous) maleic acid-modified polyolefin. Preferred examples include: However, it is not limited to these. The "copolymer" may be a block copolymer, a random copolymer, or a graft copolymer. (Hereinafter, in the case of a graft copolymer, main chain = g = side chain.)
Preferred forms of the compatibilizer are polyethylene=g=polystyrene, polyethylene=g=styrene-acrylonitrile copolymer, polypropylene=g=styrene-acrylonitrile copolymer, ethylene-ethyl acrylate copolymer=g=styrene-acrylonitrile. Copolymers, oxazoline group-containing polystyrene, polycarbonate=g=glycidyl methacrylate-styrene-acrylonitrile copolymers, maleic anhydride-modified polyolefins, and the like, with maleic anhydride-modified polyolefins being preferred.

Examples of the maleic anhydride-modified polyolefin include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified ethylene-butene copolymer, ethylene-glycidyl methacrylate copolymer, maleic anhydride-modified styrene-butadiene copolymer, etc. Maleic anhydride-modified polyethylene and maleic anhydride-modified polypropylene are preferred.

The addition mass ratio of the compatibilizer to the packaging material is preferably 0.01:99.9 to 1:99, more preferably 0.05:99.95 to 0.5:99.5. The ratio is more preferably 0.1:99.9 to 0.2:99.8. When it is within the above range, the compatibility between the resin derived from the printed layer and the polyolefin resin is improved, so that foreign matters in the film are reduced.

Commercially available products can be used as the compatibilizing agent, and examples thereof include the Admer Q series (manufactured by Mitsui Chemicals) and the Umex series (manufactured by Sanyo Chemical Co., Ltd.).

<Extrusion process>
In the extrusion step, the resin composition is discharged from the discharge section. In one embodiment, it is preferable that the discharge section includes a foreign matter separator, and the resin composition is discharged after passing through the separator.
In discharging the heated melt-kneaded resin composition, the extrusion pressure of the extrusion device is preferably 18 MPa or less, more preferably 0.1 to 18 MPa, and 1 to 18 MPa, from the viewpoint of durability of the extrusion device. It is more preferably 12 MPa, and particularly preferably 3 to 7 MPa. Note that the extrusion pressure of the extrusion device does not always need to be constant, but the extrusion pressure here is the maximum extrusion pressure during the extrusion process.
When it is within the above range, the foreign matter separation efficiency of the foreign matter separation device becomes good, so that the film foreign matter becomes good. The discharge pressure is influenced by the processing temperature, screw rotation speed, discharge rate, resin viscosity, and foreign matter separation device (screen mesh, etc.) used to remove foreign matter from the recycled polyolefin. In addition, clogging of the mesh due to insoluble matter, foreign matter, etc., and foaming caused by moisture, chlorine-containing matter, etc., can also cause changes in pressure.

<Cooling process>
In the present invention, the recycled polyolefin extruded in the extrusion step is preferably cooled in the cooling step.
Examples of the cooling method include air cooling, wind cooling, and water cooling. In the present invention, it is preferable to include a water cooling step. Cooling is preferably from 20°C to 80°C, more preferably from 30°C to 60°C. The pelletizing step described below may be carried out simultaneously.

[Recycled polyolefin]
A recycled polyolefin can be obtained from a packaging material using the method for producing recycled polyolefin described above. The recycled polyolefin includes pigments and resins from the printed layer, and inorganic layered fillers and resins from the barrier layer. Further, it may also contain additives added in the heating melt-kneading process.

<Antioxidant content in recycled polyolefin>
The antioxidant content in the recycled polyolefin is preferably 0.01 to 5% by mass, more preferably 0.01 to 3% by mass, and 0.05 to 1% by mass based on 100% by mass of the recycled polyolefin. It is more preferably 0.1% to 0.5% by mass, and particularly preferably 0.1 to 0.5% by mass. If it is within the above range, film burn will be good.
<Compatibilizer content in recycled polyolefin>
The content of the compatibilizer in the recycled polyolefin is preferably 0.01 to 3% by weight, more preferably 0.05 to 0.5% by weight based on 100% by weight of the recycled polyolefin. When it is within the above range, the film has good foreign matter.

<Melt mass flow rate (MFR) of recycled polyolefin>
The melt mass flow rate (MFR) of recycled polyolefin is greatly affected by thermal history, such as temperature during molding and cooling speed. Although it depends on the structure of the soft packaging and the recycling method, it is preferably 0.5 to 20 g/10 minutes, more preferably 3 to 15 g/10 minutes. When it is within the above range, film burnability is good and it is suitable for various moldings. In the present invention, it is also preferable to include a step of adjusting the melt mass flow rate (MFR) of the recycled polyolefin by changing the thermal history.

<Molded product>
A molded article can be obtained by molding the recycled polyolefin obtained according to the present invention. The molding method is not particularly limited, and examples include injection molding, extrusion molding, blow molding, and compression molding. Molded products can be used for a variety of purposes, such as home appliances, stationery, automobile parts, toys, sporting goods, medical supplies, and building and construction materials.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples. Note that parts and % in the present invention represent parts by mass and % by mass unless otherwise noted.

(Hydroxyl value)
The hydroxyl value is the number of mg of potassium hydroxide required to neutralize acetic acid bonded to hydroxyl groups when 1 g of a sample is acetylated, and was measured by the method described in JIS K 0070.

(Acid value)
The acid value is the number of mg of potassium hydroxide required to neutralize free fatty acids, resin acids, etc. contained in 1 g of sample, and was measured by the method described in JIS K 0070.

(amine value)
The amine value is the number of mg of potassium hydroxide equivalent to the equivalent amount of hydrochloric acid required to neutralize the amino groups contained in 1 g of the sample, and was measured in accordance with JIS K 0070. 0.5 to 2 g of the sample was accurately weighed (sample solid content: Sg), and 50 mL of a mixed solution of methanol/methyl ethyl ketone = 60/40 (mass ratio) was added to the accurately weighed sample to dissolve it. Bromophenol blue was added to the obtained solution as an indicator, and the obtained solution was titrated with a 0.2 mol/L ethanolic hydrochloric acid solution (potency: f). The end point was the point at which the color of the solution changed from green to yellow, and the amine value was determined by the following formula using the titration amount (AmL) at this time.
(Formula) Amine value = (A x f x 0.2 x 56.108)/S [mgKOH/g]

(Weight average molecular weight)
The weight average molecular weight was determined by measuring the molecular weight distribution using a gel permeation chromatography (GPC) device (HLC-8220 manufactured by Tosoh Corporation) and as a converted molecular weight using polystyrene as a standard substance. The measurement conditions are shown below.
Column: The following columns were connected in series and used.
TSKgelSuperAW2500 manufactured by Tosoh Corporation
TSKgelSuperAW3000 manufactured by Tosoh Corporation
TSKgelSuperAW4000 manufactured by Tosoh Corporation
TSKgelguardcolumnSuperAWH manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Measurement conditions: Column temperature 40℃
Eluent: Tetrahydrofuran Flow rate: 1.0 mL/min

(Glass transition point (Tg))
The glass transition point was determined by differential scanning calorimetry (DSC). The measurement was carried out using DSC8231 manufactured by Rigaku Co., Ltd. under conditions of a measurement temperature range of -70 to 250°C and a temperature increase rate of 10°C/min. The midpoint (inflection point) of the baseline shift based on the glass transition in the DSC curve was defined as the glass transition point.

(Chlorine content)
The chlorine content was measured in accordance with JIS K0127 (2013). Each printing ink was applied to a thickness of 2.0 μm on a transparent substrate to form a coating film, dried at 80° C., and 0.5 g was scraped off. The scraped coating film was pretreated by a combustion method, and the chlorine content of the resulting sample was determined by ion chromatography to determine the chlorine content.

(Measurement of melt mass flow rate (MFR))
MFR was measured by the method described in JIS K 7210-1:2014. The packaging material was measured by crushing it into pieces with side lengths of 5 mm to 10 mm. Measurement conditions such as temperature were conducted under the conditions of the sample with the highest content.

(Moisture content measurement method)
The moisture content was measured in accordance with JIS K 0068 (2001). The measuring equipment and reagents are shown below.
Measuring equipment: Karl Fischer moisture meter MKC-710D (manufactured by Kyoto Electronics Industry Co., Ltd.)
: Moisture vaporizer ADP-611 (manufactured by Kyoto Electronics Industry Co., Ltd.)
Karl Fischer reagent: Chem Aqua water standard 1 (manufactured by Kyoto Denshi Kogyo Co., Ltd.)

(Calculation of polyolefin content)
The polyolefin content in the packaging material was calculated using the following formula.
Formula (1): (mass of polyolefin resin in packaging material)/(mass of packaging material) x 100
More specifically, the following formulas (I) to (III) were applied.
Formula (I): Mass [g] per 1 ^m2 of packaging material = (Thickness of base material 1) x (Density of base material 1) + (Printing layer coating amount) + (Barrier layer coating amount) + (Adhesive Coating amount) + (base material 2 thickness) x (base material 2 density)

Formula: (II) Mass of polyolefin in packaging material [g] = (Thickness of base material 1) x (Density of base material 1) + (Thickness of base material 2) x (Density of base material 2)

Formula (III): Polyolefin content in packaging material [%] = (polyolefin mass in packaging material) / (mass per 1 m ² of packaging material) x 100

In addition, when a packaging material has a layer which is not described above, the thickness and density of the corresponding layer can be added to the calculation formula for calculation.

The densities of the base material and sealant used to construct the packaging material are as follows.
・Corona treated biaxially oriented polypropylene (OPP) film (thickness 20 μm) Density: 0.91 g/cm ³
・High-density polyethylene film (HDPE) film (thickness 20μm) Density: 0.94g/cm ³
・Linear low density polyethylene film (thickness 40μ) Density: 0.91g/cm ³
・Nylon (NY) film (thickness 15μm) Density: 1.15g/cm ³
・Unstretched polypropylene (CPP) film (thickness 20 μm) Density: 0.90 g/cm ³
・Unstretched polypropylene (CPP) film (thickness 30 μm) Density: 0.90 g/cm ³
・Unstretched polypropylene (CPP) film (thickness 60 μm) Density: 0.90 g/cm ³
・Linear low density polyethylene (LLDPE) film (thickness 150μm) Density: 0.91g/cm ³
・Linear low density polyethylene (LLDPE) film (thickness 40μm) Density: 0.91g/cm ³

(resin synthesis)
(Synthesis example 1) Urethane resin PU1
100 parts of a polyester polyol (hereinafter referred to as "MPD/SA") with a number average molecular weight of 2,000, which is a condensate of 3-methyl 1,5 pentanediol (MPD) and sebacic acid (SA), 1,4-butanediol ( 1 part of "1,4-BD"), 28.5 parts of isophorone diisocyanate (hereinafter "IPDI") and 32.1 parts of ethyl acetate were mixed and reacted at 90°C for 5 hours in a nitrogen atmosphere to A urethane prepolymer of isocyanate was obtained.
Next, 11.0 parts of isophoronediamine (hereinafter "IPDA"), 1.0 part of N-(2-aminoethyl)ethanolamine (hereinafter "AEA"), 1.0 part of dibutylamine (hereinafter "DBA") and a mixture. 298.1 parts of Solvent 1 (ethyl acetate/isopropanol = 70/30 (mass ratio)) was stirred and mixed, and the obtained urethane prepolymer of terminal isocyanate was gradually added at 40°C. The reaction was carried out at 80° C. for 1 hour to obtain a solution of urethane resin PU1 having a solid content of 30% by mass, an amine value of 6.5 mgKOH/g, a hydroxyl value of 3.8 mgKOH/g, and a weight average molecular weight of 50,000. The chlorine content of the urethane resin PU1 was 0% by mass.

(Synthesis example 2) Acrylic resin AC1
While introducing nitrogen gas into a reaction vessel equipped with a stirrer, a thermometer, two dropping funnels, and a reflux device, 400 parts of methyl isobutyl ketone was charged, and the temperature was raised to 100°C. Next, from one of the two dropping funnels, 45.6 parts of styrene, 91.2 parts of benzyl methacrylate, 136.8 parts of acrylic acid, and 91.2 parts of n-butyl acrylate were added dropwise over 3 hours. From the other side, 27.4 parts of dimethyl 2,2'-azobisisobutyrate was dissolved in 87.8 parts of methyl isobutyl ketone, and this was added dropwise over 4 hours. After the dropwise addition was completed, the reaction was further carried out for 10 hours to complete the reaction. After cooling, 106.2 parts of 28% ammonia water was added to the obtained water-soluble resin solution to make it water-soluble. Further, 500 parts of deionized water was added, and the entire amount of methyl isobutyl ketone was distilled off under azeotropy, to obtain a solution of aqueous acrylic resin (water-soluble type) AC1 having a carboxyl group. Finally, deionized water was added to adjust the solids content of the acrylic resin AC1 solution to 30%. The acid value of the acrylic resin AC1 was 120 mgKOH/g, and the weight average molecular weight was 15,000.

(Preparation of ink)
<Preparation Example 1> Gravure ink X1
10 parts of polyvinyl butyral resin PVB1 (weight average molecular weight: 89000, hydroxyl group content: 20% by mass, acetic acid group content: 2.5% by mass), 40 parts of urethane resin PU1 solution, C.I. I. Pigment Blue 15:3 (manufactured by Toyo Color Co., Ltd., product name: LIONOL BLUE FG-7330, chlorine content 0% by mass) 5 parts, mixed solvent (normal propyl acetate (NPAC)/isopropyl alcohol (IPA) = 8/2) 38.4 parts of propylene glycol monomethyl ether, 1.5 parts of water, and 0.8 parts of chlorinated polypropylene were mixed and dispersed in a bead mill for 20 minutes to obtain a pigment dispersion. 20 parts of water was stirred and mixed with the obtained pigment dispersion to obtain gravure ink X1.

<Preparation Examples 2 to 11, Comparative Adjustment Example 1> Gravure ink X2 to 12
Gravure inks X2 to X12 were obtained in the same manner as in Preparation Example 1, except that the raw materials and blending ratios listed in Table 1 were used. The properties of the raw materials used are as follows.
・Polyvinyl butyral resin (PVB2): (weight average molecular weight: 20000, hydroxyl group content: 20% by mass, acetate group content: 2.5% by mass)
・Polyvinyl butyral resin (PVB3): (weight average molecular weight: 55000, hydroxyl group content: 20% by mass, acetic acid group content: 2.5% by mass)
・Polyvinyl butyral resin (PVB4): (weight average molecular weight: 100000, hydroxyl group content: 20% by mass, acetic acid group content: 2.5% by mass)
・Polyvinyl butyral resin (PVB5): (weight average molecular weight: 160000, hydroxyl group content: 20% by mass, acetate group content: 2.5% by mass)
・Polyvinyl acetal resin (PVAc1): S-LEC KX-5 (manufactured by Sekisui Chemical Co., Ltd.)

・Polyvinyl formal resin (PVF1): Vinylec L (manufactured by JNC, weight average molecular weight: 60,000)

(Adjustment of barrier coating agent)
<Adjustment Example 12> Barrier coating agent V1
6 parts of polyvinyl alcohol resin PVA1 (ethylene content: 8 mol%) and 92 parts of mixed solvent (water/IPA = 8/2) were heated with stirring, and the heating and stirring was continued at 95°C for 1 hour. Then, heating was stopped and stirring was continued until the temperature returned to room temperature to obtain an aqueous solution of polyvinyl alcohol resin PVA1. 2 parts of montmorillonite (swellability, particle aspect ratio: 500, particle thickness: 1 μm, particle spread: 500 nm) was added to the polyvinyl alcohol resin PVA1 aqueous solution and mixed and stirred to obtain barrier coating agent V1.
<Adjustment Examples 13 to 24, Comparative Production Example 2> Barrier coating agents V2 to V14
Barrier coating agents V2 to 14 were obtained in the same manner as in Preparation Example 12, except that the raw materials and compounding ratios listed in Table 2 were used. The properties of the raw materials used are as follows.
・Polyvinyl alcohol resin PVA2: Kuraray Poval 3-98 (manufactured by Kuraray Co., Ltd., ethylene content 0 mol%)
・Polyvinyl alcohol resin PVA3: Kuraray Eval L171B (manufactured by Kuraray Co., Ltd., ethylene content 27 mol%)
・Polyvinyl alcohol resin PVA4: Kuraray Eval F104B (manufactured by Kuraray Co., Ltd., ethylene content 32 mol%)
・Polyvinyl alcohol resin PVA5: Kuraray Eval E105B (manufactured by Kuraray Co., Ltd., ethylene content 44 mol%)
・Mica: (non-swelling, aspect ratio 130, average particle size: 11 μm, oil absorption: 42 g/100 g)
・Kaolin: Varisurf HX (manufactured by Imerys, average particle size: 9.0 μm, aspect ratio: 90)
・Silica: Mizukasil P-526 (manufactured by Mizusawa Chemical Industry Co., Ltd., average particle size: 7 μm, oil absorption: 240 g/100 g)

(Manufacturing example of laminate)
<Example 1> Laminated body A1
Gravure ink X1 was diluted with a mixed solvent (isopropyl alcohol/ethyl acetate) to a Zahn cup #3 (manufactured by Rigosha) for 15 seconds (25° C.). Further, the barrier coating agent V1 was diluted with a mixed solvent (isopropyl alcohol/water) to a thickness of Zahn Cup #3 (manufactured by Rigosha Co., Ltd.) for 16 seconds (25° C.). Thereafter, the corona-treated surface of a corona-treated biaxially oriented polypropylene (OPP) film (thickness 20 μm) was printed using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm at a printing speed of 50 m/min and an in-line oven. A printing layer was formed by printing diluted gravure ink X1 at 60° C., and a printing speed of 50 m/min was applied to the printing layer using a gravure printing machine equipped with a gravure plate having a plate depth of 60 μm. A barrier layer was formed by printing the diluted barrier coating agent V1 three times in an in-line oven at 60°C. Next, a polyether-based reactive urethane adhesive ("TM-340V/CAT-29B" manufactured by Toyo Morton Co., Ltd.) is applied on the printed layer using a dry laminating machine, and the solvent is dried in an oven to form an adhesive. After forming the adhesive layer, an unstretched polypropylene (CPP) film (thickness 30 μm) was laminated onto the adhesive layer at a line speed of 40 m/min, kept warm at 40°C for 1 day, and OPP (base material 1) A laminate A1 having a configuration of /printing layer/barrier layer/adhesive layer/CPP (base material 2) was obtained. The coating amount after drying of the printing layer of laminate A1 is 2 g/m ² , the coating amount after drying of the barrier layer is 1.6 g/m ² , and the coating amount after drying of the adhesive layer is 2.5 g. / ^m2 , and the MFR value was 7g/10min.

<Examples 2 to 35, Comparative Examples 1 to 3> Laminated bodies A2 to 35, S1 to 3
Laminates A2-35 and S1-3 were obtained in the same manner as in Example 1, except that the raw materials and coating amounts listed in Table 3 or 4 were used.

<Lamination strength>
The laminates obtained in the above Examples and Comparative Examples were cut out to a length of 150 mm and a width of 15 mm, and the laminate strength in the 90° direction was measured using a tensile tester and evaluated based on the following criteria. The evaluation results are shown in Tables 3 and 4. Note that A, B, and C are within a range that causes no practical problems.
"Evaluation criteria"
A (excellent): 1.5 N/15 mm or more B (good): 1.0 N/15 mm or more but less than 1.5 N/15 mm C (acceptable): 0.8 N/15 mm or more and less than 1.0 N/15 mm D (unacceptable): 0.5N/15mm or more but less than 0.8N/15mm

<Oxygen barrier evaluation>
The obtained laminate was subjected to oxygen permeability measurement according to JIS K 7126-2:2006, and evaluated according to the following criteria. Note that A, B, and C are within a range that causes no practical problems.
"Evaluation criteria"
A (excellent): Oxygen permeability is less than 100 g/m ² ·24 h.
B (Good): Oxygen permeability is 100 g/m ² ·24 h or more and less than 1000 g/m ² ·24 h.
C (Acceptable): Oxygen permeability is 1000 g/m ² ·24 h or more and less than 10000 g/m ² ·24 h.
D (impossible): Oxygen permeability is 10,000 g/m ² ·24 h or more.

<Separability evaluation>
(Adjustment of separated liquid)
500 parts of POE stearyl ether (polyoxyethylene stearyl ether, POE addition number: 12, HLB: 13.9) as a surfactant, BYK-1650 (manufactured by BYK Chemie Japan, silicone emulsion type antifoaming agent, as an antifoaming agent) Solid content concentration 27.5%), 1000 parts of sodium hydroxide, and 48,450 parts of water were blended and stirred with a disper to obtain a separated liquid A1.

(separability test)
Into a 50 L pot, 40 L of separation liquid A1 and 1.6 kg of samples each obtained by cutting the obtained laminate into a size of 3 cm x 3 cm were placed, and the mixture was stirred at 70° C. and 2000 rpm. After stirring for 60 minutes, samples were taken, washed with water, and dehydrated. The obtained samples were visually checked to determine whether the base material 1 and the base material 2 were separated and the sample where the base material 1 and the base material 2 were not separated, and evaluated according to the following criteria. The evaluation results are shown in Tables 3 and 4.
"Evaluation criteria"
A (excellent): The mass of the sample in which base material 1 and base material 2 are separated is 95% by mass or more with respect to the total sample amount.
B (Good): The mass of the sample in which the base material 1 and the base material 2 are separated is 90 mass% or more and less than 95 mass% with respect to the total sample amount.
C (Acceptable): The mass of the sample in which base material 1 and base material 2 are separated is 85 mass% or more and less than 90 mass% with respect to the total sample amount.
D (impossible): The mass of the sample in which base material 1 and base material 2 are separated is less than 85% of the total sample amount.

<Evaluation of recyclability>
(Manufacture of recycled polyolefin)
100,000 parts of the laminate was cut into a size of 2 cm x 2 cm, washed with water, dehydrated, and dried with hot air until the moisture content became 0.5%. The laminate obtained above, Irganox 1010 (manufactured by BASF, phenolic antioxidant), and Umex 1010 (manufactured by Sanyo Chemical Industries, Ltd., maleic anhydride-modified polypropylene compatibilizer) were transferred using a twin-screw extruder (Japan Steel Works, Ltd.). (manufactured by the company, screw diameter: 34 mm, minimum gap distance between the inner wall of the cylinder and the screw: 0.4 mm), and was melted and kneaded for 30 seconds at a screw rotation speed of 200 rpm, 230° C., and an extrusion flow rate of 20 kg/h.
The mass ratio of the laminate to Irganox 1010 was adjusted to be laminate: Irganox 1010 = 99.8:0.2. Moreover, the supplied mass ratio of the laminate and Umex 1010 was adjusted to be 99.85:0.15 of the laminate: Umex 1010.
Thereafter, using a 120 mesh filter, it was extruded from the discharge part of the extrusion device. The pressure at the discharge part immediately after extrusion was 2 MPa. The extruded resin composition was immediately cut with a pelletizer and cooled by immersion in cold water. In this way, pellets of recycled polyolefin recycled from the laminate were obtained.
Note that the rotational speed of 1100 RPM is 4900 sec ^-1 when converted into a shear rate.

(Film foreign matter evaluation)
The recycled polyolefin pellets obtained in the above recycled polyolefin production were each extruded at 230° C. using a T-die extruder to produce a film-like molded product with a thickness of 50 μm. The number of visually discernable foreign objects (approximately 100 μm or more) per 0.5 m ² of the obtained film-like molded product was counted and evaluated according to the following criteria. The evaluation results are shown in Tables 3 and 4. Note that A, B, and C are within a range that causes no practical problems.
"Evaluation criteria"
A (excellent): The number of foreign substances is less than 50,
B (Good): The number of foreign substances is 50 or more and less than 100.
C (acceptable): The number of foreign objects is 100 or more and less than 200.
D (defective): The number of foreign substances is 200 or more.

(Film burn evaluation)
The film-like molded product obtained in the film foreign matter evaluation was evaluated for visually distinguishable burns according to the following criteria. The evaluation results are shown in Tables 3 and 4. Note that A, B, and C are within a range that causes no practical problems.
A (Excellent): No burnt food (no color change)
B (Good): Slightly burnt (some discoloration to light brown can be seen)
C (Acceptable): Burnt items are visible (discoloration to light brown in multiple areas or the entire area is observed)
D (defective): Many burnt items are seen (black or brown foreign objects and discolored areas are seen)

<Comprehensive evaluation of recyclability>
Regarding the above film foreign matter evaluation and film burn evaluation, the lower evaluation was taken as the overall evaluation. The evaluation results are shown in Tables 3 and 4. Note that A, B, and C are within a range that causes no practical problems.

A recycled polyolefin was manufactured using the laminate A1 in the same manner as described above (manufacturing of recycled polyolefin) except that no antioxidant was used. The obtained recycled polyolefin had a film foreign matter evaluation of A, a film burn evaluation of C, and an overall recyclability evaluation of C.

A recycled polyolefin was manufactured using the laminate A1 in the same manner as described above (manufacturing of recycled polyolefin) except that no compatibilizing agent was used. The obtained recycled polyolefin had a film foreign matter evaluation of C, a film burn evaluation of A, and an overall recyclability evaluation of C.

From the above results, in Comparative Example 1, since the base material 1 was a nylon film and did not satisfy the olefin content of the packaging material, film foreign matter and film burn were poor. Comparative Example 2 had poor lamination strength because the printed layer did not contain polyvinyl acetal resin. Comparative Example 3 had poor laminate strength, oxygen barrier properties, and separability because the barrier layer did not contain polyvinyl alcohol resin. Regarding the lamination strength of Comparative Examples 2 and 3, the adhesion between the ink layer and the barrier layer was low, resulting in delamination between the ink layer and the barrier layer, and the lamination strength was also low.
On the other hand, in the example, the barrier layer contained a polyvinyl alcohol resin, the printing layer contained a polyvinyl acetal resin, and the olefin content of the packaging material was 80% by mass or more, so the lamination strength, oxygen barrier property, separability, Film foreign matter and film burn were good.
In particular, in Examples 1, 33, 34, and 35, the polyvinyl acetal resin contained in the printing layer was a polyvinyl butyral resin with a weight average molecular weight of 60,000, and the ratio of the polyvinyl acetal resin to the urethane resin was 20:80. , the ethylene content of the polyvinyl alcohol resin contained in the barrier layer is 10 mol%, the inorganic filler is montmorillonite, the inorganic filler content is 25% by mass in 100% by mass of the barrier layer, and the packaging Since the olefin content in the material was 80% by mass or more, the laminate strength, oxygen barrier properties, separability, film foreign matter, and film burn were particularly excellent.

Claims (14)

A packaging material having a base material 1, a barrier layer, a printed layer, and a base material 2,
the barrier layer and the printing layer are in contact with each other,
The packaging material contains 80% by mass or more of a polyolefin resin in the total mass of the packaging material,
The barrier layer includes a polyvinyl alcohol resin and an inorganic layered filler ,
The inorganic layered filler is montmorillonite,
A packaging material, wherein the printing layer contains a polyvinyl acetal resin. The packaging material according to claim 1, which is for recycled polyolefin. The packaging material according to claim 1 or 2, wherein the polyvinyl acetal resin is a polyvinyl butyral resin. The packaging material according to claim 3, wherein the polyvinyl butyral resin has a weight average molecular weight of 25,000 to 200,000. The packaging according to claim 1 or 2, wherein the polyvinyl alcohol resin contains an ethylene-derived structural unit, and the content of the ethylene-derived structural unit is 1 to 40 mol% of the entire polyvinyl alcohol resin. Material. The coating amount of the printing layer is 0.1 to 12 g/m ² The packaging material according to claim 1 or 2. The coating amount of the barrier layer is 0.4 to 5 g/m ² The packaging material according to claim 1 or 2. The packaging material according to claim 1 or 2 , wherein the content of the inorganic layered filler in the total mass of the barrier layer is 1 to 40% by mass. The packaging material according to claim 1 or 2, wherein the printing layer further contains a urethane resin. The packaging material according to claim 9, wherein the ratio of polyvinyl butyral resin to urethane resin is 1:99 to 85:15. The packaging material according to claim 1 or 2 , wherein the inorganic layered filler has an aspect ratio of 300 to 2000 . The packaging material according to claim 1 or 2, wherein the polyolefin resin is polypropylene and/or polyethylene. A method for producing a packaging material having a base material 1, a barrier layer, a printed layer, and a base material 2 , the barrier layer and the printed layer being in contact with each other, and containing 80% by mass or more of a polyolefin resin,
printing a barrier coating agent containing polyvinyl alcohol resin and montmorillonite to form a barrier layer with a coating amount of 0.5 to 3 g/m ² ;
A method for manufacturing a packaging material, comprising the step of printing a printing ink containing polyvinyl butyral resin to form a printing layer. A method for producing recycled polyolefin, the method comprising: obtaining recycled polyolefin resin from packaging material using an extrusion device equipped with a first screw and a discharge section,
The packaging material has a base material 1, a barrier layer, a printed layer, and a base material 2, and contains 80% by mass or more of a polyolefin resin,
The barrier layer contains a polyvinyl alcohol resin and montmorillonite ,
The printing layer contains polyvinyl acetal resin,
Production of recycled polyolefin, comprising: a heating melt-kneading step of heating and melting and kneading the packaging material using the first screw to obtain a resin composition; and an extrusion step of extruding the resin composition from the discharge section. Method.