Recycled polyolefin films, resin laminates, and packaging materials

Abstract

The objective is to provide a recycled polyolefin film, a laminate thereof, and a packaging material thereof that exhibits relatively excellent strength even when the entire laminate, which is composed of multiple layers containing several types of resins, is mixed and melted without separating each layer. [Solution] A recyclable polyolefin film containing a compatibilizer, obtained using a recyclable material obtained by forming a polyolefin resin laminate having at least a polyolefin stretched substrate and a polyolefin sealant into pellets, wherein the content of the recyclable material is 10% by mass or more and 95% by mass or less and the content of the compatibilizer is 5% by mass or more and 90% by mass or less.

Description

Technical Field

[0001] The present invention relates to a recycled polyolefin film containing a compatibilizer, a resin laminate including at least one layer composed of the film, and a packaging material.

Background Art

[0002] Conventionally, as a plastic recycling method, thermal recycling, which recovers and reuses heat generated during combustion of waste plastics, has been mainly used. However, in May 2019, the "Plastic Resource Circulation Strategy" was formulated by the Ministry of the Environment, and it was clearly stipulated that 100% of used plastics shall be effectively utilized through reduction, recycling and other measures by 2035. Under such social circumstances, the demand for material recycling, which reuses waste plastics as raw materials for plastic products, is expected to further increase.

[0003] In material recycling, the mainstream practices are global recycling, in which waste plastics used in large-market-scale products such as films, sheets and containers are exported overseas for recycling, and cascade recycling, in which the quality of the recycled materials is lowered and the materials are used as raw materials for other small-market-scale products. However, in recent years, along with import regulations on waste plastics in Asian countries, recycled raw materials (recycled materials) are currently concentrated in products with small market scales, and it is an urgent task to expand the range of products to which recycled raw materials can be applied. In particular, horizontal recycling, which uses waste plastics as raw materials for the same type of products, is the most efficient recycling method, and the need for high-quality recycled raw materials applicable to horizontal recycling is increasing.

[0004] As a method for reusing waste plastics by horizontal recycling, for example, Patent Document 1 discloses a method in which unnecessary used shopping bags are collected, if colored portions are present, the colored portions are cut off, then the bags are crushed and melted to form repellets to obtain recycled raw materials, and further, the recycled raw materials are mixed with new raw materials to produce new shopping bags.

Prior Art Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2009-148938 [Overview of the project] [Problems that the invention aims to solve]

[0006] In horizontal recycling, it is desirable that recycled polyolefin films obtained using recycled materials have performance equivalent to that of polyolefin films obtained using unused resin (virgin resin) (virgin polyolefin films). However, conventional recycled polyolefin films obtained using recycled materials have the problem of inferior strength due to the inclusion of resins other than polyolefins.

[0007] This invention has been made in view of the current situation, and aims to provide a recycled polyolefin film, a laminate thereof, and a packaging material thereof that, despite being a laminate consisting of multiple layers containing multiple types of resins, exhibits relatively excellent strength even when the entire laminate is mixed and melted without separating each layer. Furthermore, this invention aims to provide a monomaterial laminate using the recycled polyolefin film and a packaging material thereof. [Means for solving the problem]

[0008] As a result of various studies conducted to solve the above problems, the inventors of the present invention have found that the above problems can be solved by using a compatible material in addition to a recycled material which is a polyolefin resin laminate having a polyolefin stretched substrate and a polyolefin sealant in pellet form, and based on these findings, the present invention has been completed.

[0009] In other words, according to the first invention of the present invention, a compatibilizer-containing recycled polyolefin film is provided, which contains a recycled material obtained using a recycled material obtained by forming a polyolefin resin laminate having at least a polyolefin stretched substrate and a polyolefin sealant into pellets, and a compatibilizer, characterized in that the content of the recycled material is 10% by mass or more and 95% by mass or less and the content of the compatibilizer is 5% by mass or more and 90% by mass or less. According to the second invention, a regenerated polyolefin film containing a compatibilizer, as described in the first invention, is provided, wherein the compatibilizer is an unsaturated carboxylic acid-modified polyolefin. According to the third invention, a regenerated polyolefin film containing a compatibilizer, as described in the first invention, is provided, wherein the compatibilizer is a maleic anhydride-modified polyolefin. According to the fourth invention, a regenerated polyolefin film containing a compatibilizer, as described in the first to third inventions, is provided, characterized in that the ratio (DA / DB) of the dirt drop impact test value (DA) of the regenerated polyolefin film containing the compatibilizer to the dirt drop impact test value (DB) of a regenerated polyolefin film without a compatibilizer, obtained by replacing the compatibilizer contained in the regenerated polyolefin film with virgin resin of the same content, is greater than 1.0. (The dirt drop impact test is measured with reference to JIS K7124.) According to the fifth invention, a regenerated polyolefin film containing a compatibilizer, as described in the first to third inventions, is provided, characterized in that the ratio (EA / EB) of the Elmendorff tear strength (EA) of the regenerated polyolefin film containing a compatibilizer to the Elmendorff tear strength (EB) of a regenerated polyolefin film without a compatibilizer, obtained by replacing the compatibilizer contained in the (EA / EB) regenerated polyolefin film containing a compatibilizer with virgin resin of the same content, is 1.0 or more in the direction perpendicular to the machine direction. (The Elmendorff tear strength is measured in accordance with JIS K7128-2.) According to the sixth invention, a regenerated polyolefin film containing a compatibilizer, as described in the first to third inventions, is provided, characterized in that the ratio (IA / IB) of the film impact (IA) of the regenerated polyolefin film containing a compatibilizer to the film impact (IB) of a regenerated polyolefin film without a compatibilizer, obtained by replacing the compatibilizer contained in the regenerated polyolefin film with virgin resin of the same content, is 0.9 or more. (The film impact is measured with reference to JIS K7128-2.) According to the seventh invention, a regenerated polyolefin film containing a compatibilizer, as described in the first to third inventions (the tensile test is measured in accordance with JIS K7127), is provided, characterized in that, in a tensile test of the regenerated polyolefin film containing the compatibilizer and a regenerated polyolefin film without a compatibilizer, obtained by replacing the compatibilizer contained in the regenerated polyolefin film with virgin resin of the same content, the ratio of breaking strengths in the direction perpendicular to the mechanical direction (STA / STB) is 0.8 or more. According to the eighth invention, a regenerated polyolefin film containing a compatibilizer, as described in the first to third inventions (the tensile test is measured in accordance with JIS K7127), is provided, characterized in that, in a tensile test of the regenerated polyolefin film containing the compatibilizer and a regenerated polyolefin film without a compatibilizer, obtained by replacing the compatibilizer contained in the regenerated polyolefin film with virgin resin of the same content, the ratio of breaking strengths in the mechanical direction (SMA / SMB) is 0.8 or more. According to the ninth invention, a recycled polyolefin film containing a compatibilizer, as described in the first to eighth inventions, is provided, characterized in that it includes a polyethylene resin composition that satisfies the following requirements, in addition to the recycled material and the compatibilizer. 1) Density of 0.900~0.930 g / cm³ 3 2) Melt flow rate (MFR) of 0.1-20 g / 10 min at 190°C and a 2.16 kg load. 3) The molecular weight distribution (Mw / Mn), which is the ratio of the number-average molecular weight (Mn) to the weight-average molecular weight (Mw) obtained from GPC, is between 1.8 and 3.5. According to the tenth invention, a regenerated polyolefin film containing a compatibilizer, as described in the first to ninth inventions, is provided, in which the polyolefin resin laminate is laminated with a layer containing polyamide, polyester, or ethylene-vinyl alcohol copolymer in addition to the polyolefin stretched substrate and the polyolefin sealant, and the regenerated polyolefin resin laminate is used as the regenerated material. According to the 11th invention, a resin laminate is provided which includes at least one layer made of a compatible material-containing recycled polyolefin film as described in any one of the first to tenth inventions. According to the twelfth invention, a resin laminate according to the eleventh invention is provided, characterized in that all layers constituting the resin laminate are composed of the same polyolefin-based resin composition, forming a polyolefin monomaterial resin laminate. According to the 13th invention, a packaging material is provided that uses the resin laminate described in the 11th invention. [Effects of the Invention]

[0010] The recycled polyolefin film of the present invention can provide a recycled polyolefin film that reduces environmental impact and has high strength. By using this recycled polyolefin film, it is possible to provide laminates and packaging materials with reduced environmental impact, in particular monomaterial laminates and packaging materials composed of a single material from the recycled material to the laminate and packaging material. [Modes for carrying out the invention]

[0011] The present invention relates to a recycled polyolefin film containing a compatibilizer, a laminate having a layer thereof, and a packaging material composed thereof. 1. Compatibilizer-containing recycled polyolefin film One embodiment of the present invention is a compatibilizer-containing recycled polyolefin film obtained using a recycled material obtained by forming a polyolefin resin laminate having at least a polyolefin stretched substrate and a polyolefin sealant into pellets, and a compatibilizer, characterized in that the content of the recycled material is 10% by mass or more and 95% by mass or less and the content of the compatibilizer is 5% by mass or more and 90% by mass or less (hereinafter also referred to as "the compatibilizer-containing recycled polyolefin film of the present invention"). The present invention will be described in detail item by item below.

[0012] (1) Polyolefin resin laminate The polyolefin resin laminate used in the recycled polyolefin film of the present invention comprises a polyolefin stretched substrate and a polyolefin sealant. By using polyolefin for both the stretched substrate and the sealant layer, the recyclability of the packaging material laminate can be improved. Furthermore, by using the same polyolefin for both the stretched substrate and the sealant layer, the recyclability of the packaging material laminate can be further improved.

[0013] (1-1) Polyolefin stretched substrate In this specification, a polyolefin stretched substrate means a stretched film obtained by stretching a film obtained from a polyolefin resin composition by inflation molding or T-die molding, which is used as a substrate for a resin laminate. Polyolefin stretched substrates are obtained by stretching a base film made of a polyolefin resin composition. Methods for manufacturing the base film include inflation molding, T-die molding, and calendering, but inflation molding or T-die molding are preferred from the viewpoint of production speed and ease of manufacture. Furthermore, the substrate may be a single-layer film using a single polyolefin resin composition, or a multilayer film using multiple polyolefin resin compositions. The stretched base material may be a uniaxially stretched film or a biaxially stretched film. As the stretching method, any of longitudinal uniaxial stretching, transverse uniaxial stretching, sequential biaxial stretching, and simultaneous biaxial stretching can be used.

[0014] (1-2) Polyolefin Sealant In the present specification, the polyolefin sealant is a film that includes at least one layer composed of a polyolefin resin composition, and is characterized in that sealing can be achieved by fusion bonding of this layer. A known technique can be used as the method for producing the sealant film. Specific examples include inflation molding, T-die molding, and calender molding, with inflation molding and T-die molding being preferred. The thickness of the sealant film is not particularly limited, but is preferably 10 to 200 μm, more preferably 30 to 180 μm. The sealant may have a single-layer structure or a multi-layer structure.

[0015] (1-3) Polyolefin Resin Composition The polyolefin resin composition used as the raw material for the polyolefin stretched base material and the polyolefin sealant in the present invention means both a single resin or a mixture, such as polyethylene resin, propylene homopolymer, propylene-ethylene random copolymer, polypropylene-based resin such as propylene-ethylene block copolymer, polybutene resin, and poly-4-methyl-pentene-1 resin, and necessary additives may be added thereto.

[0016] (Polyethylene Resin Composition) The polyethylene resin for constituting the polyethylene resin composition is produced by using either or both of ethylene derived from petroleum raw materials and ethylene derived from biomass raw materials as raw materials, and using a conventionally known catalyst such as a metal catalyst including a Ziegler-Natta catalyst, a Phillips catalyst, and a metallocene catalyst. In general, these catalysts are in a state where a complex composed of an organometallic compound is supported on a carrier such as silica or a Mg compound.

[0017] Polymerization methods include high-pressure methods, solution methods, slurry methods, and gas-phase methods. The high-pressure method uses a catalyst consisting of a radical source such as oxygen or peroxide, or a metal complex, as an initiator, and polymerizes ethylene, comonomers, and the initiator by introducing them into a reaction vessel under high temperature and high pressure conditions. Depending on the shape of the reaction vessel, it can be further divided into the tubular method and the autoclave method. The solution method is a polymerization method in which the polymer is dissolved in a hydrocarbon solvent at a temperature above the melting point of the polymer. The slurry method is a polymerization method in which a hydrocarbon compound such as hexane or isobutane is used as the solvent, and the resulting polyethylene exists in the solvent as a slurry. Depending on the shape of the reaction vessel, it can be broadly divided into the autoclave method and the loop-pipe method. The gas-phase method is a polymerization method in which ethylene and α-olefin as a comonomer, and hydrogen as a chain transfer agent are fed in gaseous form from the bottom of a vertical reaction vessel, and a polymerization catalyst is introduced thereto (edited by Kazuo Matsuura and Naotaka Mikami / Polyethylene Technology Reader). The polyethylene resin composition of the present invention is preferably one polymerized using a metal catalyst. The polyethylene resin compositions obtained by these manufacturing methods have a wide range of combinations of densities, melt flow rates (MFRs), and other resin properties to meet various conventionally known applications.

[0018] The polyethylene resin composition may be an ethylene homopolymer, or a copolymer of ethylene and one or more α-olefins selected from α-olefins having 3 to 18 carbon atoms. Preferably, the α-olefins have 3 to 12 carbon atoms, and examples include propylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene. Furthermore, the total content of these α-olefins is usually selected to be 30 mol% or less, preferably 20 mol% or less. Within this range, the flexibility and heat resistance of films and the like are good.

[0019] Here, the α-olefin content is a value measured by 13C-NMR under the following conditions. Device: JEOL-GSX270 (manufactured by JEOL Corporation) Concentration: 300mg / 2mL Solvent: Orthodichlorobenzene

[0020] (Polypropylene resin) Polypropylene resins are resins containing propylene polymers. Propylene polymers are polymers containing more than 50% by mass of monomer units derived from propylene, that is, propylene homopolymers or propylene copolymers containing more than 50% by mass of monomer units derived from propylene. The propylene copolymer is preferably a copolymer of ethylene and / or α-olefins having 4 to 10 carbon atoms and propylene. For propylene homopolymers, the melt flow rate (MFR), measured at a temperature of 230°C and a load of 2.16 kg, is preferably 0.1 g / 10 min to 50 g / 10 min. For copolymers of ethylene and / or α-olefins having 4 to 10 carbon atoms and propylene, the melt flow rate (MFR), measured at a temperature of 230°C and a load of 2.16 kg, is preferably 10 g / 10 min to 200 g / 10 min. The MFR is measured according to Method A as specified in JIS K7210-1. When the total mass of the copolymer of ethylene and / or α-olefins having 4 to 10 carbon atoms and propylene is taken as 100% by mass, the content of monomer units derived from ethylene and / or α-olefins having 4 to 10 carbon atoms is preferably 0.1% to 40% by mass, and the content of monomer units derived from propylene is preferably 60% to 99.9% by mass. Examples of α-olefins having 4 to 10 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene. Preferably, the α-olefin having 4 to 10 carbon atoms is 1-butene, 1-hexene, or 1-octene. Specific examples of copolymers of ethylene and / or α-olefins having 4 to 10 carbon atoms with propylene include copolymers of propylene and ethylene, copolymers of propylene and α-olefins having 4 to 10 carbon atoms, and copolymers of propylene, ethylene and α-olefins having 4 to 10 carbon atoms. Note that the copolymer of ethylene and / or α-olefins having 4 to 10 carbon atoms with propylene may be used alone or in combination of two or more types. Furthermore, the propylene-based polymer may be a mixture of a propylene homopolymer and a copolymer of ethylene and / or α-olefins having 4 to 10 carbon atoms with propylene. Examples of copolymers of propylene and α-olefins having 4 to 10 carbon atoms include propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-1-octene copolymer, and propylene-1-decene copolymer. Examples of copolymers of propylene, ethylene, and α-olefins having 4 to 10 carbon atoms include propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, propylene-ethylene-1-octene copolymer, and propylene-ethylene-1-decene copolymer.

[0021] (1-4) Structure and manufacturing method of polyolefin resin laminates A polyolefin resin laminate is a resin laminate comprising a layer made of a polyolefin stretched substrate and a polyolefin sealant as a sealant layer, and is obtained by laminating the polyolefin stretched substrate and the polyolefin sealant. Here, the ratio (mass ratio) of the polyolefin resin laminate to the polyolefin sealant content of the polyolefin stretched substrate is preferably 1 / 1 or less, and more preferably 1 / 4 or less.

[0022] (1-5) Adhesive layer The polyolefin resin laminate may include an adhesive layer between the polyolefin stretched substrate and the sealant layer. Examples of the adhesive layer include an adhesive layer composed of an extruded resin layer mainly containing polyethylene and an adhesive. In one embodiment, the polyolefin resin laminate comprises an extruded resin layer mainly containing polyethylene between a polyolefin stretched substrate and a sealant layer. The extruded resin layer functions as an adhesive layer between the two. By including an extruded resin layer containing polyethylene as the main component as the adhesive layer in the polyolefin resin laminate, the polyolefin content in the laminate can be increased compared to when using conventional non-polyethylene adhesives (e.g., two-component curing polyurethane adhesives). This improves the recyclability of the laminate. The extruded resin layer contains polyethylene as its main component. Details of the polyethylene are as described above in the section on polyethylene resin composition. The polyethylene in the extruded resin layer and the polyethylene in the sealant layer may be the same or different. From the viewpoint of adhesion, the polyethylene contained in the extruded resin layer is preferably at least one selected from low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene, with low-density polyethylene or linear low-density polyethylene being more preferred. From the viewpoint of reducing environmental impact, recycled polyethylene may be used as the polyethylene.

[0023] As a method for laminating a stretched polyethylene substrate as the base material and a sealant film as the sealant layer, for example, a melt extrusion lamination method using a molten resin mainly containing polyethylene, particularly a sand lamination method, can be used. This allows for a higher polyethylene content in the laminate. Furthermore, compared to laminating them by dry lamination, for example, the time required for the drying and aging processes can be reduced, thus improving the production efficiency of the laminate. In one embodiment, the polyolefin resin laminate includes an adhesive layer, which is made of an adhesive, between the polyolefin stretched substrate and the sealant layer. This can improve, for example, the adhesion strength between the two.

[0024] The adhesive may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may be a solvent-based adhesive or a solvent-free adhesive. Examples of solvent-based adhesives include rubber-based adhesives, vinyl-based adhesives, olefin-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and urethane-based adhesives. Examples of solvent-free adhesives include polyether-based adhesives, polyester-based adhesives, silicone-based adhesives, epoxy-based adhesives, and urethane-based adhesives. Among these, urethane-based adhesives are preferred, and two-component curing urethane-based adhesives are more preferred.

[0025] Examples of adhesive coating methods include the direct gravure roll coating method, the gravure roll coating method, the kiss coat method, the reverse roll coating method, the fontein method, and the transfer roll coating method. The thickness of the adhesive layer formed by the above adhesive is preferably 0.1 μm or more, more preferably 0.2 μm or more, even more preferably 0.5 μm or more, preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 6 μm or less. A polyolefin resin laminate can be manufactured by laminating a stretched polyolefin substrate as a base material and a sealant film as a sealant layer using the above-mentioned adhesive. The laminate of this disclosure may be manufactured by laminating using a solvent-type adhesive dry lamination method, for example, or by laminating using a solvent-free adhesive non-solvent lamination method.

[0026] (1-6) Layer comprising at least one selected from polyamide, polyester, or ethylene-vinyl alcohol copolymer. The polyolefin resin laminate may, if necessary, further have a base layer or intermediate layer comprising at least one selected from polyamide, polyester, or ethylene-vinyl alcohol copolymer. Specific examples of resins include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate; polyamide resins such as nylon 6, nylon 66, and MXD6 (polymetaxylylene adipamide); and ethylene-vinyl alcohol copolymers. In one embodiment, the resin layer is a co-extruded resin film. In one embodiment, the above-mentioned resin layer is a resin film obtained by co-extruding a material constituting a polyolefin layer, a material constituting an adhesive resin layer, and a material constituting the above-mentioned resin layer using a co-extrusion inflation molding method or the like, and then further stretching the resulting film. In one embodiment, the above-mentioned resin layer includes an adhesive layer composed of an adhesive.

[0027] (2) Recycled material In the recycled polyolefin film of the present invention, it is important to use recycled material obtained by forming a polyolefin resin laminate having a polyolefin stretched substrate and a polyolefin sealant into pellets. By using this recycled material, it is possible to provide a polyolefin film, laminate, and packaging material with reduced environmental impact. The recycled material is obtained by cutting or crushing a polyolefin resin laminate containing a stretched polyolefin substrate and a polyolefin sealant to fragment it, heating and melting and kneading it, further extruding it, and then cooling and shredding the extruded resin composition. Preferably, the polyolefin resin laminate is washed, and further dehydrated and dried.

[0028] (3) Compatibilizer The compatibilizer in this invention is a component that improves the compatibility of the molten mixture when a polyolefin laminate is melted, thereby achieving effects such as homogenization and increased strength. In the present invention, the content of the compatibilizer is preferably 5% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 80% by mass or less, and even more preferably 10% by mass or more and 70% by mass or less. If the compatibilizer content is lower than the above range, the compatibilization effect may not be fully realized, and if it is higher than the above range, the film strength of the recycled resin obtained by remelting may decrease. Specific examples of compatibilizers depend on the type of resin component constituting the polyolefin laminate, but in the present invention, unsaturated carboxylic acid-modified polyolefins are preferred, and among these, maleic anhydride-modified polyolefins are more preferred. Furthermore, unsaturated carboxylic acid-modified polyethylene is preferred, and among these, maleic anhydride-modified polyethylene is more preferred.

[0029] (4) Compatibilizer-containing recycled polyolefin film (4-1) Formulation of recycled polyolefin film containing compatibilizer The content of the recycled material in the compatibilizer-containing recycled polyolefin film of the present invention is 10% by mass or more and 95% by mass or less, preferably 20% by mass or more and 90% by mass or less, and more preferably 30% by mass or more and 90% by mass or less. The compatibilizer content in the compatibilizer-containing recycled polyolefin film of the present invention is preferably 5% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 80% by mass or less, and even more preferably 10% by mass or more and 70% by mass or less. Furthermore, the compatibilizer-containing recycled polyolefin film of the present invention may also contain polyolefin resins other than recycled materials. As polyolefin resins other than recycled materials, polypropylene resins such as polyethylene resin, propylene homopolymer, propylene-ethylene random copolymer, and propylene-ethylene block copolymer, as well as polybutene resin and poly-4-methylpentene-1 resin, can be used, either as a single resin or a mixture thereof. Furthermore, the compatible agent-containing recycled polyolefin film of the present invention may also contain additives. Examples of additives include antioxidants, weathering agents, lubricants, anti-blocking agents, antistatic agents, anti-fogging agents, anti-drip agents, pigments, fillers, and the like.

[0030] (4-2) Production of recycled polyolefin film containing compatibilizer A regenerated polyolefin film containing a compatibilizer can be manufactured by known techniques using a composition (regenerated material composition) containing a regenerated material, a compatibilizer, and an optional additive. Specifically, this can be done by inflation molding, T-die molding, or calendering, with inflation molding and T-die molding being preferred. The regenerated polyolefin film of the present invention may have a single-layer structure or a multi-layer structure.

[0031] (4-3) Characteristics of recycled polyolefin film containing compatibilizer The recyclable agent-containing recycled polyolefin film of the present invention reduces environmental impact and can improve strength compared to recycled polyolefin films that do not contain a recyclable agent. One preferred embodiment of the recycled polyolefin film of the present invention is a recycled polyolefin film having the following properties.

[0032] (Characteristic 1) The ratio (DA / DB) of the dirt drop impact test value (DA) of a recycled polyolefin film containing a compatibilizer to the dirt drop impact test value (DB) of a recycled polyolefin film without a compatibilizer is greater than 1.0. Here, the dirt drop impact test value is measured in accordance with JIS K7124. Characteristic 1 indicates that when a dirt drop impact test is measured for a recycled polyolefin film without a compatibilizer (where the compatibilizer in a compatibilizer-containing recycled polyolefin film is replaced with an equal amount of virgin resin), the ratio of the two (i.e., dirt drop impact test of the compatibilizer-containing recycled polyolefin film / dirt drop impact test of the compatibilizer-free recycled polyolefin film) is greater than 1.0. Due to characteristic 1, recycled polyolefin films obtained using conventional recycled materials have inferior impact strength, but by including a compatibilizer, it is possible to obtain recycled polyolefin films with superior impact strength. Here, the virgin resin has a composition corresponding to the sealant of the polyolefin resin laminate, which is the raw material for the recycled material that constitutes the recycled polyolefin film. Another preferred embodiment of the recycled polyolefin film of the present invention is a recycled polyolefin film having the following properties.

[0033] (Characteristic 2) The ratio (EA / EB) of the Elmendorf tear strength (EA) of a recycled polyolefin film containing a compatibilizer to the Elmendorf tear strength (EB) of a recycled polyolefin film without a compatibilizer is 1.0 or greater in the direction perpendicular to the machine direction. Here, the Elmendorf tear strength is measured in accordance with JIS K7128-2. Due to characteristic 2, recycled polyolefin films obtained using conventional recycled materials have inferior tear strength, but by including a compatibilizer, it is possible to obtain a recycled polyolefin film with excellent tear strength in the direction perpendicular to the machine direction. Another preferred embodiment of the recycled polyolefin film of the present invention is a recycled polyolefin film having the following properties. (Characteristic 3) The ratio (IA / IB) of the film impact (IA) of a recycled polyolefin film containing a compatibilizer to the film impact (IB) of a recycled polyolefin film without a compatibilizer is 0.9 or higher. Film impact is measured according to JIS K7128-2. Due to characteristic 3, by including a compatibilizer, it is possible to obtain a recycled polyolefin film that contains virgin resin and has relatively good impact strength, similar to recycled polyolefin films that do not contain a compatibilizer. Another preferred embodiment of the recycled polyolefin film of the present invention is a recycled polyolefin film having the following properties.

[0034] (Characteristic 4) In tensile tests of a recycled polyolefin film containing a compatibilizer and a recycled polyolefin film without a compatibilizer, the ratio of the breaking strengths in the direction perpendicular to the machine direction is 0.8 or higher, preferably 0.9 or higher. If the tensile breaking strength of the recycled polyolefin film containing a compatibilizer in the direction perpendicular to the machine direction is (STA) and the tensile breaking strength of the recycled polyolefin film without a compatibilizer in the same direction is (STB), then the ratio is STA / STB. Here, the tensile test is measured in accordance with JIS K7127. Due to characteristic 4, by including a compatibilizer, it is possible to obtain a recycled polyolefin film with relatively good tensile strength, similar to a recycled polyolefin film containing virgin resin but without a compatibilizer. Another preferred embodiment of the recycled polyolefin film of the present invention is a recycled polyolefin film having the following properties.

[0035] (Characteristic 5) In tensile tests of a recycled polyolefin film containing a compatibilizer and a recycled polyolefin film without a compatibilizer, the ratio of the breaking strength in the mechanical direction is 0.8 or higher, preferably 0.9 or higher. If the tensile breaking strength in the mechanical direction of the recycled polyolefin film containing a compatibilizer is (SMA) and the tensile breaking strength in the direction perpendicular to the mechanical direction of the recycled polyolefin film without a compatibilizer is (SMB), then the ratio is SMA / SMB. Here, the tensile test is performed in accordance with JIS K7127. Due to characteristic 5, by including a compatibilizer, it is possible to obtain a recycled polyolefin film with relatively excellent tensile strength, similar to a recycled polyolefin film containing virgin resin but without a compatibilizer. In one preferred embodiment of the recycled polyolefin film of the present invention, it has any one of the properties (1) to (5).

[0036] Furthermore, in a more preferred embodiment of the recycled polyolefin film of the present invention, it has any two of the properties (1) to (5). Furthermore, in a more preferred embodiment of the recycled polyolefin film of the present invention, it has any three of the properties (1) to (5). Furthermore, in a more preferred embodiment of the recycled polyolefin film of the present invention, it has any four of the properties (1) to (5). Furthermore, in a particularly preferred embodiment of the recycled polyolefin film of the present invention, it possesses any of the properties (1) to (5).

[0037] Another preferred embodiment of the recycled polyolefin film of the present invention includes, in addition to the recycled material, a polyethylene resin composition (hereinafter also referred to as "polyethylene resin composition A") that satisfies the following requirements. 1) Density of 0.900~0.930 g / cm³ 3 2) Melt flow rate (MFR) of 0.1-20 g / 10 min at 190°C and a 2.16 kg load. 3) The molecular weight distribution (Mw / Mn), which is the ratio of the number-average molecular weight (Mn) to the weight-average molecular weight (Mw) obtained from GPC, is between 1.8 and 3.5. By including the above polyethylene resin composition, a regenerated polyolefin film containing a compatibilizer with relatively excellent tear strength, impact strength, and tensile strength can be obtained. In one embodiment of the recycled polyolefin film of the present invention, the total mass of the compatibilizer-containing recycled polyolefin film is 100% by mass, preferably containing 10% to 95% by mass of recycled material, 5% to 90% by mass of compatibilizer, and 0% to 85% by mass of polyethylene resin composition A. More preferably containing 30% to 70% by mass of recycled material, 5% to 50% by mass of compatibilizer, and 25% to 65% by mass of polyethylene resin composition A.

[0038] 2. Resin laminate Another embodiment of the present invention is a resin laminate comprising at least one layer made of a regenerated polyolefin film containing the compatibilizer of the present invention (hereinafter also referred to as "the resin laminate of the present invention"). The resin laminate of the present invention may consist of at least one polyolefin resin composition, in addition to the compatibilizer-containing recycled polyolefin film of the present invention, and may also include a film (other film) obtained by inflation molding or T-die molding. Furthermore, the method of laminating the recycled polyolefin film with other films according to the present invention may involve further stretching of the co-extruded film obtained by co-extrusion molding, or by bonding the films together using an adhesive. The resin laminate may include a layer made of stretched film as a base material and a polyethylene-based resin sealant as a sealant layer. The resin laminate may be composed entirely of polyethylene-based resin or polypropylene-based resin. This resin laminate can be treated as a monomaterial resin laminate. That is, in one preferred embodiment of the present invention, the resin laminate is a polyolefin monomaterial resin laminate in which all layers constituting the resin laminate are composed of the same polyolefin resin composition. The proportion of the main component in the monomaterial resin laminate is not particularly limited, but is preferably 80% by weight, and more preferably 90% by weight.

[0039] (glue) Adhesives can be used to laminate the above-mentioned resin laminates. The adhesive used contains at least one resin composition, but is not particularly limited. Examples of adhesives that can be used include epoxy, acrylic, and urethane types. Furthermore, adhesives containing any of the above resin compositions are not particularly limited, but one-component, two-component, or hot-melt types may be used as needed. Furthermore, using barrier adhesives such as PASLIM (manufactured by DIC Corporation) or Maxive (manufactured by Mitsubishi Gas Chemical Company) is preferable because it reduces the amount of other barrier materials used and increases the proportion of polyolefin in the resin laminate.

[0040] 3. Packaging materials The laminate of the present invention can be used particularly suitably for packaging material applications. That is, another embodiment of the present invention is a packaging material using the resin laminate of the present invention (hereinafter also referred to as "the packaging material of the present invention"). The shape of the packaging material is not particularly limited and may be a packaging bag or a stand-up pouch. In the case of a stand-up pouch, only the body may be formed from the resin laminate, only the bottom may be formed from the resin laminate, or both the body and the bottom may be formed from the resin laminate. [Examples]

[0041] The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. The test and evaluation methods and materials used in the examples are as follows. 1. Testing and evaluation methods <Evaluation Method> (1) Density Measurements were taken in accordance with JIS K6922-1 and 2. (2) MFR Measurements were taken in accordance with JIS K6922-2, under conditions of 190°C and a 2.16 kg load. (3)Molecular weight distribution Measurements were taken using GPC (Gel Permeation Chromatography) under the following conditions.

[0042] [Measurement conditions] Equipment used: Polymer Char HT GPC-IR System Detector: IR-6 Measurement temperature: 145℃ Solvent: Orthodichlorobenzene (ODCB) (trimethylphenol 3.6g / 18L added as antioxidant) Columns: Showa Denko Shodex HT-806M x 2 Flow rate: 1.0mL / min Injection volume: 20μL • Sample preparation The sample was placed in vials at a dose of 5-8 mg and set up in an autosampler. The autosampler was programmed to inject 8 mL of solvent (room temperature) and dissolve the sample at 150°C for 2 hours. Heptane was used as a flow marker for pump flow rate correction. • Creation of a calibration curve Calibration curves were created using standard polystyrene and converted to polyethylene equivalents. The standard polystyrene samples used were the Showdex Standard SM-105 sample set, as well as n-eicosane and n-tetracontane. • Calculation of molecular weight Measurements were performed under the aforementioned conditions, and chromatograms were recorded with a sampling interval of 1 s. Chromatogram recording (data acquisition) and average molecular weight calculation were performed using dedicated software (GPC One, manufactured by Polymer Char) on a PC with Microsoft Windows® 10 installed.

[0043] (4)Environmental load The following criteria were used to assess the environmental impact. ○: Made with recycled materials ×: No recycled materials used (5) Breaking strength Measurements were taken using the following equipment and conditions, referencing JIS K7127. MD represents the flow direction (Machine Direction), and TD represents the value in the transverse direction (Transverse Direction). Equipment: Tensilon universal testing machine manufactured by Orientec Co., Ltd. Test specimen: A test specimen type 5 as specified in JIS K7127 was used. Tensile speed: 500 mm / min Chuck spacing: 65mm Measurement environment: temperature 23℃, humidity 50%

[0044] (6) Elmendorf tear strength Measurements were taken using the following equipment and conditions in accordance with JIS K7128-2. MD represents the flow direction (Machine Direction), and TD represents the value in the transverse direction (Transverse Direction). Equipment: Digital Elmendorf tear tester, model SA (manufactured by Toyo Seiki Seisakusho Co., Ltd.) Measurement environment: temperature 23℃, humidity 50%

[0045] (7) Film Impact A Toyo Seiki Seisakusho film impact tester (FILM IMPACT TESTER; hereinafter simply referred to as "the test machine") was used to measure the amount of work required for penetration failure per unit film thickness. Specifically, the test film was stored in a 23°C-50% atmosphere and conditioned. The test film was then fixed to the test machine in a 50mm diameter holder, and a 1-inch (25.4mm) hemispherical metal object was struck through the inner layer surface of the test film at the penetration point to measure the amount of work required for penetration failure. At that time, the load was removed and the maximum scale (work) was set to 1.5J. The value obtained by dividing the work by the film thickness was defined as the film impact value.

[0046] (8) DDI (Dirt Drop Impact Test Value) Measurements were taken in reference to JIS K7124-1. The test equipment used was a Tester Sangyo Co., Ltd. IM-302 dart impact tester. A sample film was clamped, and a weight holder was installed on a support column 66 cm above the film surface. A weight (dart) consisting of a Φ38 mm aluminum hemisphere and a 150 mm long shaft was set to an arbitrary weight and placed in the weight holder. The weight was then allowed to free-fall, and the rupture of the film surface was visually judged. Five measurements were taken for each dart weight. If the film did not rupture in all five measurements, the weight of the dart was increased by a certain percentage, and the measurement was repeated. If the film ruptured in all five measurements, the weight of the dart was decreased by a certain percentage, and the measurement was repeated. The measurement was continued in this manner, changing the weight, until the weight of the dart that did not rupture in all five measurements and the weight of the dart that ruptured in all five measurements were determined. Finally, the 50% fracture mass (M50) and 50% fracture energy (E50) of the film sample were calculated using the following formulas [1][2]. [1] M50 = WS(T / 100 - 1 / 2) [2] E50 = M50 × g × H W: Minimum mass at fracture of all test samples (g) S: Mass interval (g) during repeated testing T: Sum of the destruction rates of the 5 film samples in each test mass (%) H: Distance from the film sample surface to the tip of the dirt (m) g:Gravity acceleration (9.81m / s2)

[0047] <Preparation of polyolefin laminates to be used as raw materials for recycled materials> As the polyolefin stretching substrate, Tokyo Ink's Hybron (25 μm thick; high-density polyethylene uniaxially oriented film) was used. In addition, as the polyolefin sealant, resin composition A (manufactured by Nippon Polyethylene Co., Ltd., Harmolex® registered trademark, grade name NF366A (linear low-density polyethylene)) was used, and a 120 μm film was formed in an inflation molding machine at 180°C and a blow ratio of 1.9. Next, a 3 μm layer of dry laminating adhesive (ether-based urethane adhesive) was applied to the stretched polyolefin substrate. Then, the polyolefin sealant was bonded to the substrate layer via this adhesive layer. As described above, a polyolefin resin laminate, which will serve as the raw material for recycled materials, was fabricated. In the above polyolefin resin laminate, the ratio (mass ratio) of the polyolefin stretched substrate to the polyolefin sealant is 1 / 4.6. Furthermore, the density of resin composition A (polyethylene resin composition A) is 0.919 g / cm³. 3 At 190°C and a 2.16 kg load, the melt flow rate (MFR) is 1.6 g / 10 min, and the Mw / Mn ratio is 3.19.

[0048] <Production of recycled materials> The above polyolefin resin laminate was cut, melted, kneaded, and extruded from the discharge section of an extruder. Afterward, it was cooled by immersion in cold water and cut with a pelletizer. In this way, recycled material was obtained from the above polyolefin resin laminate.

[0049] [Example 1-1] A dry blend of 30% of the above recycled material, 60% of resin composition A, and 10% of a compatibilizer (manufactured by Nippon Polyethylene Co., Ltd., Lexpar® ET, grade name ET530H (ethylene-methyl acrylate-maleic anhydride copolymer)) was used to produce a 50 μm film that was blow-molded at 180°C with a blow ratio of 2.0. The environmental impact, Elmendorf tear strength, film impact, tensile strength, and DDI are shown in Table 1. [Comparative Example 1-1] A film was formed in the same manner as in Example 1-1, except that 30% of the recycled material and 70% of resin composition A were used. Table 1 shows the environmental impact, Elmendorf tear strength, film impact, tensile strength, and DDI. Table 2 also shows the ratios of Elmendorf tear strength, film impact, breaking strength, and DDI between the regenerated polyolefin film containing compatibilizer of Example 1-1 and the regenerated polyolefin film of Comparative Example 1-1.

[0050] [Example 2-1] Multilayer films were formed using a 5-layer inflation molding machine at 210°C and a blow ratio of 1.5, with the film configuration shown in Table 3. The environmental impact, Elmendorf tear strength, film impact, tensile strength, and DDI are shown in Table 4. [Comparative Example 2-1] A multilayer film was formed under the same conditions as in Example 2-1, except that the film configuration was changed as shown in Table 3. The environmental impact, Elmendorf tear strength, film impact, breaking strength, and DDI are shown in Table 4.

[0051] Examples 2-1 and Comparative Example 2-1 used resin composition A (manufactured by Nippon Polyethylene Co., Ltd., Harmolex®, grade name NF396A), resin composition B (manufactured by Nippon Polyethylene Co., Ltd., trade name Novatec LL, linear low-density polyethylene, grade name UF421), and compatibilizer (manufactured by Nippon Polyethylene Co., Ltd., Lexpearl® ET, grade name ET530H (ethylene-methyl acrylate-maleic anhydride copolymer)) as raw materials. Table 5 also shows the ratios of Elmendorf tear strength, film impact, breaking strength, and DDI between the multilayer film containing the recyclable agent-containing recycled polyolefin film of Example 2-1 and the multilayer film containing the recycled polyolefin film of Comparative Example 2-1.

[0052] [Table 1]

[0053] [Table 2]

[0054] [Table 3]

[0055] [Table 4]

[0056] [Table 5]

[0057] [Industrial applicability] According to the present invention, it is possible to provide a recycled polyolefin film that reduces environmental impact and improves strength. Therefore, the recycled polyolefin film of the present invention can be suitably used in applications such as laminates, packaging materials, and especially polyolefin monomaterial laminates and polyolefin monomaterial packaging materials in which all constituent layers are composed of the same polyolefin resin composition.

Claims

1. A recyclable material containing a compatibilizer, comprising a recyclable material obtained using a recyclable material in which a polyolefin resin laminate having at least a polyolefin stretched substrate and a polyolefin sealant is formed into pellets, characterized in that the content of the recyclable material is 10% by mass or more and 95% by mass or less, and the content of the compatibilizer is 5% by mass or more and 90% by mass or less.

2. The regenerated polyolefin film containing the compatibilizer according to claim 1, wherein the compatibilizer is an unsaturated carboxylic acid-modified polyolefin.

3. The regenerated polyolefin film containing the compatibilizer according to claim 1, wherein the compatibilizer is a maleic anhydride-modified polyolefin.

4. The regenerated polyolefin film containing a compatibilizer, according to any one of claims 1 to 3, is characterized in that the ratio (DA / DB) of the dirt drop impact test value (DA) of the regenerated polyolefin film containing the compatibilizer to the dirt drop impact test value (DB) of a regenerated polyolefin film without a compatibilizer, obtained by replacing the compatibilizer contained in the regenerated polyolefin film containing the compatibilizer with virgin resin of the same content, is greater than 1.0 (the dirt drop impact test value is measured with reference to JIS K7124).

5. The regenerated polyolefin film containing a compatibilizer, according to any one of claims 1 to 3, is characterized in that the ratio (EA / EB) of the Elmendorff tear strength (EA) of the regenerated polyolefin film containing the compatibilizer to the Elmendorff tear strength (EB) of a regenerated polyolefin film without a compatibilizer, obtained by replacing the compatibilizer contained in the regenerated polyolefin film with virgin resin of the same content, is 1.0 or greater in the direction perpendicular to the machine direction (the Elmendorff tear strength is measured in accordance with JIS K7128-2).

6. The regenerated polyolefin film containing a compatibilizer, according to any one of claims 1 to 3, is characterized in that the ratio (IA / IB) of the film impact (IA) of the regenerated polyolefin film containing the compatibilizer to the film impact (IB) of a regenerated polyolefin film without a compatibilizer, obtained by replacing the compatibilizer contained in the regenerated polyolefin film containing the compatibilizer with virgin resin of the same content, is 0.9 or more (film impact is measured with reference to JIS K7128-2).

7. In a tensile test of the aforementioned regenerated polyolefin film containing a compatibilizer and a regenerated polyolefin film without a compatibilizer, obtained by replacing the compatibilizer contained in the aforementioned regenerated polyolefin film with virgin resin of the same content, the ratio of the breaking strength in the direction perpendicular to the mechanical direction is 0.8 or more, as described in any one of claims 1 to 3 (the tensile test is measured in accordance with JIS K7127).

8. In a tensile test of the aforementioned recyclable polyolefin film containing a compatibilizer and a recyclable polyolefin film without a compatibilizer, obtained by replacing the compatibilizer contained in the aforementioned recyclable polyolefin film with virgin resin of the same content, the ratio of the breaking strength in the mechanical direction is 0.8 or more, as described in any one of claims 1 to 3 (the tensile test is measured in accordance with JIS K7127).

9. A recycled polyolefin film containing a compatibilizer according to any one of claims 1 to 3, characterized in that it includes a polyethylene resin composition that satisfies the following requirements in addition to the recycled material and the compatibilizer. 1) Density of 0.900–0.930 g / cm³ ３ 2) Melt flow rate (MFR) of 0.1-20 g / 10 min at 190°C and a 2.16 kg load. 3) The molecular weight distribution (Mw / Mn), which is the ratio of the number-average molecular weight (Mn) to the weight-average molecular weight (Mw) obtained from GPC, is between 1.8 and 3.

5.

10. A regenerated polyolefin film containing a compatibilizer according to any one of claims 1 to 3, wherein the polyolefin resin laminate is used as a recycled material, comprising laminating a layer containing at least one selected from polyamide, polyester, or ethylene-vinyl alcohol copolymer in addition to the polyolefin stretched substrate and the polyolefin sealant.

11. A resin laminate comprising at least one layer made of a compatible material-containing recycled polyolefin film according to any one of claims 1 to 3.

12. The resin laminate according to claim 11, characterized in that all layers constituting the resin laminate are composed of the same polyolefin-based resin composition, forming a polyolefin monomaterial resin laminate.

13. A packaging material using the resin laminate described in claim 11.

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