Resin composition, molded article, packaging, and method for manufacturing the resin composition

Abstract

To provide a polyamide-based resin composition and a polyolefin-based resin composition which have low degrees of oxidation degradation and can be recycled for application of a molding by being separated from a molding containing a polyamide-based resin layer.SOLUTION: A polyamide-based resin composition (R1) has a chemiluminescence integrated value after kept at 150°C for 60 minutes after its temperature has been raised from 50°C at 10°C / min in nitrogen gas atmosphere according to JIS K 7351:2018 of 3,500,000-20,000,000 counts.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polyamide resin composition, a polyolefin resin composition, a molded article and a package using these resin compositions, and a method for producing these resin compositions.

Background Art

[0002] Laminates (laminated films) using plastic films have been widely spread and used as packaging materials for foodstuffs, pharmaceuticals, industrial components and the like. In recent years, however, due to environmental issues, development for reducing environmental load through recycling has been urgently promoted. On the other hand, in order to satisfy required performance such as durability, long-term storage stability, and sealing property, packaging materials using plastic films have been enhanced in functionality by combining the functions of respective layers through multilayering. For example, from the viewpoint of gas barrier properties effective for reducing food loss, an aromatic polyamide resin layer, a saponified ethylene-vinyl acetate copolymer (EVOH) layer, an inorganic vapor-deposited film layer, and the like are arranged; from the viewpoint of mechanical strength of the packaging material, an aliphatic polyamide resin layer, a polyester-based resin layer, and the like are arranged; and from the viewpoint of sealing property, a polyethylene-based resin layer having high heat-sealing suitability is arranged. Further, high functionality has been achieved by laminating a plurality of types of films having respective functions by a dry lamination method.

[0003] For recycling these laminates (laminated films), peeling and separation for each layer are required, and technological development has been carried out. For example, Patent Document 1 discloses a technique using a laminate, which is suitably used for applications such as industrial materials, agricultural materials, and packaging materials, and has excellent recyclability enabling separation and recovery, characterized by having at least one layer that can be partially or completely dissolved by treatment with an acid or alkali aqueous solution, and at least one recoverable polymer layer.

[0004] Patent Document 2 describes a method for efficiently separating and recovering plastics, aluminum, etc., from a mixed plastic, in which "ethylene glycol (EG) is used in a wet specific gravity differential separation liquid that does not dissolve the mixed plastic, and PO (polyolefin resin), PS (polystyrene), ABS (acrylonitrile-butadiene-styrene copolymer), PET (polyethylene terephthalate), PVC (polyvinyl chloride), and aluminum are separated at a heating temperature near their melting point (120-170°C), and then PVC, aluminum, etc. are separated by sedimentation with a water and ethylene glycol mixture. The EG is then separated and recovered." The technology disclosed states that any shortage is recycled and reused from the PET depolymerization process. Furthermore, PET, PVC, aluminum, etc. are depolymerized by heating at atmospheric pressure (170°C to 186°C) in EG and NaOH to produce terephthalate and EG. PVC is dechlorinated and hydrogen chloride becomes NaCl. Meanwhile, solid materials such as PO, PVC, and aluminum are dissolved in a solvent such as xylene, and the aluminum and solid materials are recovered by drying off the adhering solvent. Furthermore, the mixed solution of PO, terephthalate, and NaOH is heated and vacuum evaporated to separate the solvent, which is then recycled and reused, and washed with water to separate it into PO, terephthalate, and NaOH.

[0005] Patent Document 3 discloses a method for recycling a multilayer film containing a plastic layer mainly composed of polyester (PET), polypropylene (PP), and polyethylene (PE), and an aluminum layer. Furthermore, it discloses a method for separating and recycling valuable components from multilayer plastic packaging films that are discarded without being recycled, using a selective aluminum dissolution step, a specific gravity difference separation step, a selective extrusion step based on a melting point difference, and a selective dissolution step with an organic solvent. This method involves selectively dissolving the aluminum in the multilayer film waste to induce layer separation, separating it into a mixed layer of PP and PE and a PET layer using a specific gravity difference, and further separating the main components of the multilayer film into PET, a mixed layer of PP and PE, and an aluminum component by extracting the PP and PE contained in the PET layer using an organic solvent at 100°C or its boiling point to increase the purity of the PET separated by the specific gravity difference.

[0006] Patent Document 4 discloses a technique for recycling polyolefin-containing waste by contacting the mixture with a liquid filter aid using a solvent having specific Hansen parameters, and then separating the polyolefin from the mixture. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2001-58372 [Patent Document 2] Japanese Patent Publication No. 2006-110531 [Patent Document 3] Japanese Patent Publication No. 2006-205160 [Patent Document 4] Special table 2019-531212 publication [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, since Patent Documents 1 to 3 do not disclose techniques for molded articles (laminated articles, laminated films) containing an adhesive layer or techniques for dissolving the adhesive layer, it was not possible to separate the polyamide resin from the laminate. If these disclosed techniques were applied to molded articles (laminated articles, laminated films) containing a polyamide resin layer, the polyamide resin would undergo significant hydrolysis and oxidative degradation due to processes such as using acids or alkalis or organic solvents at high temperatures of around 100°C to 186°C, making it impossible to reuse such polyamide resins. Furthermore, while Patent Document 4 describes polyamide resin layers and adhesives, upon investigation of this technology, it was found that the resulting polyamide resin composition undergoes very strong oxidative degradation and turns brown, making it unsuitable for reuse as a raw material for molded articles. Therefore, since it was not possible to obtain reusable polyamide resin, molded articles containing a polyamide resin layer were discarded without being sent to the process of extracting recycled resin. Consequently, even if a molded article contained a polyolefin resin layer, no recycled polyolefin resin could be obtained.

[0009] This invention was made in view of the above circumstances, and its objective is to obtain a polyamide resin composition and a polyolefin resin composition that have a low degree of oxidative degradation and can be reused for molded article applications by separating them from a molded article containing a polyamide resin layer. [Means for solving the problem]

[0010] [1] A polyamide resin composition (R1) characterized in that, in accordance with JIS K7351:2018, the integrated chemiluminescence value during heating from 50°C at a rate of 10°C / min and holding at 150°C for 60 minutes under a nitrogen gas atmosphere is 3,500,000 to 20,000,000 counts. [2] The polyamide resin composition (R1) described in [1], wherein the mass-average molecular weight is 40,000 or more and 100,000 or less. [3] The polyamide resin composition (R1) according to [1] or [2], wherein the yellowness b* is 1.0 or more and 30.0 or less.

[0011] [4] A polyamide resin composition (R1) according to any one of [1] to [3], comprising a product separated from a molded article (M0) which includes at least a polyamide resin layer. [5] The polyamide resin composition (R1) according to [4], wherein the molded body (M0) is a laminate including an adhesive layer. [6] The adhesive layer comprises a polyester adhesive, the polyamide resin composition (R1) according to [5].

[0012] [7] A polyamide resin molded article (M1) having a content of 1% by mass or more and 100% by mass or less of the polyamide resin composition (R1) described in any one of items [1] to [6]. [8] A polyamide resin molded article (M1) characterized in that, in accordance with JIS K7351:2018, the integrated chemiluminescence value during heating from 50°C at a rate of 10°C / min and holding at 150°C for 60 minutes under a nitrogen gas atmosphere is 3,500,000 to 20,000,000 counts. [9] A polyamide resin molded article (M1) according to [7] or [8], wherein the shape is a film or a sheet.

[0013]

[10] A polyamide resin molded article (M1) according to any one of items [7] to [9], wherein the yellowness b* is 1.0 or more and 30.0 or less.

[11] A polyamide resin molded article (M1) according to any one of [7] to

[10] , wherein the molded article (M1) is 100% by mass, and further comprises 1% by mass or more and / or 20% by mass of an antioxidant and / or a heat stabilizer. A packaging body made using a polyamide resin molded article (M1) described in any one of items

[12] [9] to

[11] .

[0014]

[13] A method for producing a resin composition (R0), characterized by cutting a molded article (M0) containing at least a polyamide resin layer into a polygon with a long side of 20 mm or less, immersing it in a release agent (A), and obtaining a resin composition (R0) containing a polyamide resin composition (R1).

[14] A method for producing the resin composition (R0) according to

[13] , wherein the molded body (M0) is a laminate including an adhesive layer. A method for producing the resin composition (R0) according to

[14] , wherein the adhesive layer according to

[14] comprises a polyester adhesive.

[0015] A method for producing a polyamide resin composition (R1) by separating the resin composition (R0) obtained by the method described in any one of items

[13] to

[15] by the difference in specific gravity.

[17] A polyolefin resin composition (R2), wherein in accordance with JIS K7351:2018, an integrated chemiluminescence value counted from when temperature is increased from 50°C at a rate of 15°C / min to when temperature is held at 200°C for 60 minutes in a nitrogen gas atmosphere is 700,000 to 15,000,000 counts.

[18] The polyolefin resin composition (R2) according to

[17] , which has a mass average molecular weight of 40,000 or more and 200,000 or less.

[0016]

[19] The polyolefin resin composition (R2) according to

[17] or

[18] , which has a yellowness b* of 1.0 or more and 10.0 or less.

[20] The polyolefin resin composition (R2) according to any one of

[17] to

[19] , which contains a separated product obtained from a molded article (M0) including at least a polyamide resin layer.

[21] The polyolefin resin composition (R2) according to

[20] , wherein the molded article (M0) is a laminate including an adhesive layer.

[0017]

[22] The polyolefin resin composition (R2) according to

[21] , wherein the adhesive layer according to

[21] contains a polyester-based adhesive.

[23] A polyolefin resin molded article (M2), wherein the content of the polyolefin resin composition (R2) according to any one of

[17] to

[22] is 1% by mass or more and 100% by mass or less.

[24] A polyolefin resin molded article (M2), wherein in accordance with JIS K7351:2018, an integrated chemiluminescence value counted from when temperature is increased from 50°C at a rate of 15°C / min to when temperature is held at 200°C for 60 minutes in a nitrogen gas atmosphere is 700,000 to 15,000,000 counts.

[0018]

[25] The polyolefin resin molded article (M2) according to

[23] or

[24] , which is in the form of a film or a sheet.

[26] The polyolefin resin molded article (M2) according to any one of

[23] to

[25] , which has a yellowness b* of 1.0 or more and 10.0 or less.

[27] The polyolefin resin molded article (M2) according to any one of

[23] to

[26] , wherein the polyolefin resin molded article (M2) is 100% by mass, and further comprises 1% by mass or more and / or 20% by mass of an antioxidant and / or a heat stabilizer.

[0019] A packaging body made using a polyolefin resin molded article (M2) described in any one of items

[28]

[23] to

[27] . A method for producing a polyolefin resin composition (R2), wherein the resin composition (R0) obtained by the method described in any one of items

[29]

[13] to

[15] contains a polyolefin resin layer, and the polyolefin resin composition (R2) is obtained by separating the resin composition (R0) by the difference in specific gravity. [Effects of the Invention]

[0020] According to the present invention, by separating polyamide resins from molded articles containing polyamide resins, reusable polyamide resin compositions with a low degree of oxidative degradation can be obtained, and these can be reused in molded articles such as films. In other words, this invention is a useful invention relating to recycling technology for polyamide resins and polyolefin resins, which are being developed with the aim of reducing environmental impact. Therefore, it can reduce the consumption of petroleum resources and contribute to the construction of a circular economy. [Modes for carrying out the invention]

[0021] The polyamide resin composition (R1) of the present invention can be obtained by separating it from a molded article (M0), such as a laminate (laminated film) containing at least a polyamide resin layer, using a solvent, and a polyamide resin molded article (M1), such as a film or sheet, can be produced from the polyamide resin composition (R1). Furthermore, if the molded article (M0), such as a laminate (laminated film) containing at least a polyamide resin layer, also contains a polyolefin resin layer, such as a sealant film, a polyolefin resin composition (R2) can be obtained in the same manner, and a polyolefin resin molded article (M2), such as a film or sheet, can be produced from this polyolefin resin composition (R2). Hereinafter, the polyamide resin composition (R1) may be referred to as resin composition (R1), the polyolefin resin composition (R2) as resin composition (R2), the polyamide resin molded article (M1) as molded article (M1), and the polyolefin resin molded article (M2) as molded article (M2).

[0022] Conventional solvent-based separation techniques result in severe oxidative degradation of polyamide resins. Even if separation is possible, the resulting resins suffer from reduced mechanical strength and increased yellowing, making them unsuitable for reuse in molded products such as packaging or injection-molded articles. However, the polyamide resin composition (R1) of the present invention exhibits a low degree of oxidative degradation, making it reusable for molded product applications. Furthermore, because a reusable polyamide resin composition (R1) can be obtained, if a polyolefin resin is also present in the molded product (M0) containing the polyamide resin layer, a polyolefin resin composition (R2) can also be obtained and reused.

[0023] <Characteristics of the resin composition (R1)(R2) and molded articles (M1)(M2)> (Integrated chemiluminescence value) The degree of oxidative degradation can be determined by detecting the extremely weak light emitted when the peroxyl radicals (ROO·) produced by the oxidative degradation of the resin become peroxides (ROOH), which then decompose to become ROO· again, generating excited carbonyls in a high-energy state and singlet oxygen, one of the reactive oxygen species. The amount of light emitted can then be measured to determine the amount of ROOH produced, i.e., the degree of oxidative degradation. Specifically, in accordance with JIS K7351:2018, a chemiluminescence analyzer is used to uniformly place 100 mg of powdered polyamide resin composition (R1) or polyamide resin molded product (M1) into a 20 mm diameter aluminum cup. Under a nitrogen gas atmosphere, the temperature is raised from 50°C to 150°C at a rate of 10°C / min and held at 150°C for 60 minutes, during which the amount of chemiluminescence is measured every second. The background value is also measured and subtracted to obtain the integrated chemiluminescence value, which is the sum of the chemiluminescence values ​​over the measurement temperature and time range, allowing for the examination of the degree of oxidative degradation of the polyamide resin composition (R1) or polyamide resin molded product (M1). The polyamide resin composition (R1) or polyamide resin molded product (M1) used as the test material is processed into powder using a cryogenic pulverizer manufactured by Nippon Analytical Engineering Co., Ltd., by performing two cycles of [cooling for 5 minutes - pulverizing for 5 minutes]. The polyamide resin composition (R1) and polyamide resin molded article (M1) of the present invention are preferable to have a low chemiluminescence integrated value, which is between 3,500,000 and 20,000,000 counts, with an upper limit of preferably 19,000,000 counts or less, and more preferably 18,000,000 counts or less.

[0024] Furthermore, in the case of polyolefin resin compositions (R2) and polyolefin resin molded articles (M2), the integrated chemiluminescence value can be determined in the same manner as for polyamide resin compositions (R1) and polyamide resin molded articles (M1), except that the temperature conditions of the chemiluminescence analyzer are increased from 50°C to 200°C at a rate of 15°C / min and held at 200°C for 60 minutes. The chemiluminescence integrated value of the polyolefin resin composition (R2) and the polyolefin molded article (M2) is preferably 700,000 to 15,000,000 counts, with an upper limit of preferably 14,000,000 counts or less, and more preferably 13,000,000 counts or less.

[0025] (molecular weight) Furthermore, while oxidative degradation of resins reduces their molecular weight and inherent mechanical strength, the polyamide resin composition (R1), polyamide resin molded article (M1), polyolefin resin composition (R2), and polyolefin resin molded article (M2) of the present invention exhibit only slight oxidative degradation, resulting in minimal reduction of molecular weight. The mass-average molecular weight of the polyamide resin composition (R1) and the polyamide resin molded article (M1) is preferably 40,000 or more and 100,000 or less. The lower limit is more preferably 42,500 or more, and even more preferably 45,000 or more, while the upper limit is more preferably 90,000 or less, and even more preferably 85,000 or less. The mass-average molecular weight of the polyamide resin composition (R1) and the polyamide resin molded article (M1) is obtained by derivatization (acylation) using trifluoroacetic anhydride at room temperature using a known method, followed by stirring and drying solidification under conditions of 40°C, dissolving the solidified material in the state where no gel has formed with the eluent tetrahydrofuran, and analyzing the unswelled liquid state using gel permeation chromatography with a column oven temperature of 40°C and an RI (differential refraction) detector, and then analyzing it on a standard polystyrene basis.

[0026] The mass-average molecular weight of the polyolefin resin composition (R2) and the polyolefin resin molded article (M2) is preferably 40,000 or more and 110,000 or less. The lower limit is more preferably 42,500 or more, and even more preferably 45,000 or more, and the upper limit is more preferably 100,000 or less, and even more preferably 90,000 or less. The mass-average molecular weight of the polyolefin resin composition (R2) and polyolefin resin molded article (M2) can be measured by high-temperature gel permeation chromatography (high-temperature GPC method). After dissolving in o-dichlorobenzene at 135°C with added dibutylhydroxytoluene (BHT), the molecular weight was measured using a high-temperature GPC system. Polystyrene was used as the standard sample, and the mass-average molecular weight (Mw) was determined. The molecular weight was calculated by converting a calibration curve created using the standard polystyrene sample to polyethylene equivalent using a general-purpose calibration curve. The mass-average molecular weight of the polyolefin resin composition (R2) and polyolefin resin molded article (M2) is preferably 40,000 or more and 200,000 or less. The lower limit is more preferably 42,500 or more, and even more preferably 45,000 or more, and the upper limit is more preferably 180,000 or less, and even more preferably 150,000 or less.

[0027] (yellowness b*) Furthermore, while resins tend to turn yellowish or brownish when they undergo oxidative degradation, the polyamide resin composition (R1), polyamide resin molded article (M1), polyolefin resin composition (R2), and polyolefin resin molded article (M2) of the present invention exhibit less oxidative degradation and therefore less yellowing. The yellowness b* of the polyamide resin composition (R1) and the polyamide resin molded article (M1) is preferably 1.0 or more and 30.0 or less, more preferably 27.0 or less, and even more preferably 25.0 or less. The yellowness b* of the polyolefin resin composition (R2) and the polyolefin resin molded article (M2) is preferably 1.0 or more and 10.0 or less, with an upper limit of preferably 9.7 or less, and more preferably 9.5 or less. The yellowness level b* can be measured in accordance with JIS Z8722:2009.

[0028] (trace contaminants) Furthermore, the polyamide resin composition (R1) and polyamide resin molded article (M1) of the present invention are preferable to have less contamination of components other than polyamide resin in the molded article (M0) by the process of crushing the molded article (M0) or separating it into resin types using a solvent. The content of components other than polyamide resin is preferably 3.0% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.0% by mass or less. The impurities can be identified by dissolving the composition (R1) and molded body (M1) in a solvent, separating the soluble and insoluble components, and qualitatively analyzing them using methods such as 1H-NMR or infrared absorption spectroscopy (IR). Furthermore, the content can be determined from the dry masses of the soluble and insoluble components relative to the dry masses of the composition (R1) and molded body (M1).

[0029] The molded article (M1) and its moldability (M2) are determined by the content of the resin composition (R1) or resin composition (R2) according to the required specifications such as mechanical strength, thermophysical properties, and transparency, but it is preferable that they have the following characteristics.

[0030] (Tensile elongation at break (MPa), tensile elongation at break (%)) The tensile strength at break (MPa) and tensile strength at break (%) are measured in accordance with JIS K7129:1999. Specifically, a dumbbell-shaped test piece with a width of 6 mm is tested with a grip distance of 80.0 mm and a test speed of 50 mm / min, and the tensile strength at break and tensile strength at break are measured. The polyamide resin molded article (M1) preferably has a tensile strength of 50 MPa or more, and more preferably 60 MPa or more. Furthermore, the tensile strength at break preferably has been 200% or more, and more preferably 250% or more. The polyolefin resin molded article (M2) preferably has a tensile strength of 10 MPa or more, and more preferably 13 MPa or more. Furthermore, the tensile elongation at break is preferably 150% or more, and more preferably 180% or more.

[0031] (Destructive energy (J)) The fracture energy (J) is measured in accordance with JIS K7211-2:2006. Specifically, the fracture energy was calculated using a Shimadzu HTM-1 hydroshot impact tester, with the test specimen fixed with clamps, measured at a test speed of 3 m / sec, with a punching jig of 1 / 2 inch diameter, a striker tip diameter of 1 / 2 inch diameter, a punching support of 50 mm diameter, and in a 23°C atmosphere. For polyamide resin molded articles (M1), a fracture energy of 1.5 J or higher is preferred, and 1.8 J or higher is more preferred. The polyolefin resin molded article (M2) preferably has a fracture energy of 0.5 J or more, and more preferably 0.8 J or more.

[0032] <Fabrication of polyamide resin molded product (M1)> The polyamide resin molded article (M1) of the present invention can be produced using the polyamide resin composition (R1) described above. The polyamide resin molded article (M1) may be formed by mixing a new polyamide resin or other thermoplastic resin with a polyamide resin composition (R1) separated and regenerated from a molded article (M0) containing at least one polyamide resin layer. When the polyamide resin molded article (M1) is 100% by mass, the content ratio of the polyamide resin composition (R1) can be between 1% by mass and 100% by mass, and the content ratio can be selected according to the required specifications of the molded article (M1), such as mechanical strength, thermal properties, and transparency. Furthermore, a higher content ratio of the separated and regenerated polyamide resin composition (R1) is preferable from the viewpoint of adapting to the thermal economy and reducing environmental impact.

[0033] The shape of the polyamide resin molded product (M1) is not particularly limited, but examples include structures made using molds of various shapes, injection-molded products such as containers, and films and sheets of various thicknesses. When the polyamide resin composition (R1) is reused in a film, it is preferable that the film contains 1% to 100% by mass of the polyamide resin composition (R1) and 0% to 99% by mass of the new polyamide resin, when the film is 100% by mass. From the viewpoint of the mechanical strength and transparency of the film, it is more preferable that the film contains 1% to 50% by mass of the polyamide resin composition (R1) and 50% to 99% by mass of the new polyamide resin. There are no particular restrictions on the type of new polyamide resin, but from the viewpoint of compatibility and miscibility, it is preferable that it be the same type of polyamide resin as the polyamide resin composition (R1).

[0034] The film may be a single-layer film or a multi-layer film, and may be unstretched, uniaxially oriented, or biaxially oriented. In the case of multilayer films, there are no restrictions on the position of the layer in which the polyamide resin composition (R1) is used, but it is preferable to use it in an inner layer rather than a surface layer in order to suppress the bleed-out of low molecular weight substances from the polyamide resin composition (R1). Furthermore, depending on the desired application and function, layers containing polyethylene, polypropylene polyolefin resins, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyvinyl alcohol resins, ethylene vinyl alcohol resins, polystyrene resins, polyvinyl chloride resins, acrylic resins, thermoplastic elastomers, and acid-modified versions thereof can be arranged.

[0035] The polyamide resin molded article (M1) of the present invention can be mixed with various known additives. Examples include fillers, lubricants, antiblocking agents, antioxidants, heat stabilizers, ultraviolet absorbers, colorants, antifogging agents, mold release agents, etc. In particular, for the purpose of preventing degradation, it is preferable to include 1% to 20% by mass of antioxidants and / or heat stabilizers, and more preferably 2% to 15% by mass, when the molded article is 100% by mass.

[0036] A known method can be used to manufacture the film. For example, in the case of a co-extruded multilayer film, it is desirable to pre-dry the polyamide resin composition (R1) and other raw material resins to reduce their moisture content to 0.1% by mass or less. Then, these raw materials are fed into each extruder, the molten resins are combined in a feed block, a flat die or annular die of a multi-manifold, and then co-extruded as a multilayer film. After rapid cooling, a flat or annular unstretched film can be obtained. The temperature of the extruder containing the polyamide resin composition (R1) is preferably 200 to 300°C.

[0037] To obtain a biaxially oriented film, an unstretched film is biaxially stretched in the direction of film flow (longitudinal direction, MD) and the width direction perpendicular to it (transverse direction, TD) using known methods such as tenter-type sequential biaxial stretching, tenter-type simultaneous biaxial stretching, or tubular-type simultaneous biaxial stretching. For example, in the tenter-type sequential biaxial stretching method, the unstretched film is heated to a temperature range of 40 to 100°C, stretched longitudinally using a roll-type longitudinal stretcher, and then stretched transversely using a tenter-type transverse stretcher at a temperature range of 150 to 230°C. In the case of tenter-type simultaneous biaxial stretching or tubular-type simultaneous biaxial stretching methods, for example, the film can be produced by stretching in both the longitudinal and transverse directions simultaneously at a temperature range of 40 to 230°C. The stretching ratio is preferably 1.5 to 5.0 times in the film's flow direction (longitudinal direction, MD) and width direction (transverse direction, TD), and more preferably 2.0 to 4.5 times in each direction. Having the stretching ratio in the biaxial stretching direction within this range promotes stretch orientation, resulting in good mechanical properties such as film strength.

[0038] Furthermore, to improve the dimensional stability of the film, the biaxially oriented film can be heat-set. The heat-set temperature is preferably 200°C to 225°C, and more preferably 205°C to 220°C. This makes it possible to obtain a biaxially oriented film with good dimensional stability at room temperature. To alleviate the stress caused by crystallization shrinkage due to thermal fixation, a relaxation treatment can be performed during thermal fixation in the width direction by 0 to 15%, preferably 3 to 10%. Furthermore, after the relaxation treatment, the material can be re-stretched at a temperature of 140°C to 200°C by a range of 2 to 9%, preferably 3 to 7%, and more preferably 4 to 7% in the width direction. If the re-stretching temperature is within the above range, an appropriate stress is obtained during stretching, resulting in uniform stretching and a more even lateral shrinkage rate in the width direction.

[0039] <Fabrication of polyolefin resin molded articles (M2)> The polyolefin resin molded article (M2) can be produced using the polyolefin resin composition (R2) described above. The polyolefin resin molded article (M2) may be formed by mixing a new polyolefin resin or other thermoplastic resin with a polyolefin resin composition (R2) separated and regenerated from a molded article (M0) containing at least one polyamide resin layer. When the molded article is 100% by mass, the content ratio of the polyolefin resin composition (R2) can be between 1% by mass and 100% by mass, and the content ratio can be selected according to the required specifications of the molded article (M2), such as mechanical strength, thermal properties, and transparency. Furthermore, a higher content ratio of the separated and regenerated polyamide resin composition (R2) is preferable from the viewpoint of adapting to the thermal economy and reducing environmental impact.

[0040] There are no particular restrictions on the shape of the polyolefin resin molded product (M2), but examples include structures made using molds of various shapes, injection molded products such as containers, and films and sheets of various thicknesses. When the polyolefin resin composition (R2) of the present invention is reused in a film, it is preferable that the film contains 1% to 100% by mass of the polyolefin resin composition (R2) and 0% to 99% by mass of the new polyolefin resin, when the film is 100% by mass. From the viewpoint of the mechanical strength and transparency of the film, it is more preferable that the film contains 1% to 50% by mass of the polyolefin resin composition (R2) and 50% to 99% by mass of the new polyolefin resin. There are no particular restrictions on the type of new polyolefin resin, but from the viewpoint of compatibility and miscibility, it is preferable that it be the same type of polyolefin resin as the polyolefin resin composition (R2).

[0041] The film may be a single-layer film or a multi-layer film. In the case of a multi-layer film, there are no restrictions on the position of the layer containing the polyolefin resin composition (R2), but it is preferable to use it in an inner layer rather than a surface layer in order to suppress the bleed-out of low molecular weight substances from the polyolefin resin composition (R2). Furthermore, depending on the desired application and function, layers containing polyamide resins such as polyamide 6 and polyamide 66, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyvinyl alcohol resins, ethylene vinyl alcohol resins, polystyrene resins, polyvinyl chloride resins, acrylic resins, thermoplastic elastomers, and acid-modified versions thereof can be arranged.

[0042] The film may be unstretched, uniaxially oriented, or biaxially oriented, and can be manufactured using known methods. Unstretched film is frequently used when it is intended to be a sealant film. Unstretched films can be produced, for example, by melt-kneading a resin composition at a set temperature of 150 to 250°C using a single-screw or twin-screw extruder and then extruding it, using known methods such as the inflation method or the T-die method.

[0043] The polyolefin resin molded article (M2) of the present invention can be mixed with various known additives. Examples include fillers, lubricants, antiblocking agents, antioxidants, heat stabilizers, ultraviolet absorbers, colorants, antifogging agents, mold release agents, etc. In particular, for the purpose of preventing deterioration, it is preferable that the molded article contains 1% to 20% by mass of antioxidants and / or heat stabilizers, and more preferably 2% to 15% by mass, when the molded article is 100% by mass.

[0044] <Package> A packaging body can be manufactured using a polyamide resin molded article (M1), such as a film, containing the polyamide resin composition (R1) of the present invention. Similarly, a packaging body can be manufactured using a polyolefin resin molded article (M2), such as a film, containing the polyolefin resin composition (R2). The composition, shape, and manufacturing method of the packaging are not limited, but examples include bags and pouches; lids; cups, trays, and bottom materials for deep-drawn molded products, and can be manufactured by known methods.

[0045] <Molded article containing a polyamide resin layer (M0)> The polyamide resin composition (R1) and polyolefin resin composition (R2) of the present invention can be obtained by separating them from a molded article (M0) containing at least a polyamide resin layer. The molded article (M0) is not particularly limited, but examples include structures made using molds of various shapes, injection-molded articles such as containers, films of various thicknesses, and sheets. Among these, laminates such as laminated films made by laminating films used as packaging materials for food products, pharmaceuticals, industrial parts, etc. are preferred because the product has a short lifespan as a molded article, is mostly discarded, and recycling is necessary from the viewpoint of curbing marine pollution and depletion of petroleum resources, and because the polyamide resin composition (R1) and polyolefin resin composition (R2) are relatively easy to separate from the molded article (M0). For example, a film containing at least one polyamide resin layer (hereinafter referred to as a polyamide resin film) or a laminate (laminated film) obtained by dry laminating a polyamide resin film and another film such as a sealant film via an adhesive is preferred.

[0046] (Polyamide resin film) The polyamide resin film constituting the molded article (M0), which includes at least one polyamide resin layer, may be a single-layer film or a multi-layer film, and may be one sheet or multiple sheets. It may also be an unstretched film, a uniaxially oriented film, or a biaxially oriented film. There are no particular restrictions on the polyamide resin used in the polyamide resin film; various known resins such as aliphatic polyamides, aromatic polyamides, and semi-aromatic polyamides can be used. Examples of aliphatic polyamides include polyamide 4, polyamide 6, polyamide 7, polyamide 11, polyamide 12, polyamide 46, polyamide 410, polyamide 510, polyamide 66, polyamide 69, polyamide 610, polyamide 611, polyamide 6 / 66, polyamide 6 / 610, polyamide 6 / 611, polyamide 612, polyamide 6 / 612, polyamide 810, polyamide 910, polyamide 1010, and polyamide 1012. Examples of aromatic polyamide resins include polymetaxylylene adipamide (polyamide MXD6), metaxylylene / paraxylylene adipamide copolymers, and copolymers obtained by copolymerizing these with aliphatic diamines, alicyclic diamines, aromatic diamines, aromatic dicarboxylic acids, lactams, ω-aminocarboxylic acids, aromatic aminocarboxylic acids, etc. Examples of semi-aromatic polyamides include polyamide 4T, polyamide 5T, polyamide M-5T, polyamide 6T, polyamide 6I, polyamide 9T, polyamide 10T, polyamide 11T, polyamide 12T, and the like. These may be used individually or in combination of two or more types. In particular, polyamide 6 and polyamide 66 are used in general-purpose polyamide resin films due to their mechanical properties and toughness, while metaxylylenediamine adipamide is used to impart gas barrier properties. Separating these polyamide resins from molded products (M0) and reusing them as recycled polyamide resin compositions (R1) is an important matter in forming a circular economy and a circular society. Furthermore, from the perspective of reducing environmental impact, regenerating polyamide resin compositions (R1) from molded articles (M0) containing biomass-derived polyamide 610, polyamide 1010, and polyamide 11 can further contribute to the formation of a circular economy and a circular society. Furthermore, in order to impart flexibility to the film, if the layer containing polyamide resin is 100% by mass, it may also contain 1 to 30% by mass of thermoplastic elastomers such as polyolefin, polyamide, polyester, polystyrene, or polyvinyl chloride.

[0047] When the polyamide resin film is a multilayer film, a co-extruded multilayer film is preferred, and in addition to the polyamide resin layer, layers containing polyethylene, polypropylene polyolefin resins, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyvinyl alcohol resins, ethylene vinyl alcohol resins, polyvinyl chloride resins, acrylic resins, thermoplastic elastomers, and acid-modified products thereof can be arranged. Furthermore, the surface of the polyamide resin film may be provided with a printed layer for decorative purposes and to explain the packaged product, an inorganic vapor-deposited film layer for gas barrier properties, conductivity, non-conductivity, etc., and a coating layer containing polyvinylidene chloride, polyvinyl alcohol, ethylene vinyl alcohol, etc. for gas barrier properties, etc. There are no particular restrictions on the thickness of each polyamide resin film, but it is preferably 5 to 50 μm, more preferably 8 to 30 μm, and even more preferably 10 to 25 μm.

[0048] (Other films) The molded body (M0) may also be a laminate (laminated film) obtained by laminating a polyamide resin film and another film using an adhesive layer. Other films are not particularly limited, but examples include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyvinyl chloride resins, polyvinyl alcohol resins, ethylene vinyl alcohol resins, polyvinyl chloride resins, and acrylic resins. These may be unstretched or stretched films. Furthermore, the film surface may be provided with a printed layer for decorative purposes or to describe the packaged product, an inorganic vapor-deposited film layer for gas barrier properties, conductivity, non-conductivity, etc., or a coating layer containing polyvinylidene chloride, polyvinyl alcohol, ethylene vinyl alcohol, etc. for gas barrier properties, etc. Among these, sealant films made of polyolefin are frequently used for heat sealing to form a package. There are no particular restrictions on the thickness of each film, and it can be appropriately selected according to the function of each film. Generally speaking, from the standpoint of handling and cost-effectiveness of the film, a thickness of 3 to 200 μm is preferred, and 5 to 100 μm is more preferred.

[0049] (Sealant film) The sealant film constituting the molded body (M0) (laminated body, laminated film) may be a single-layer film or a multi-layer film, and may be an unstretched film, a uniaxially oriented film, or a biaxially oriented film. Furthermore, it may be applied to at least one side of the molded body or to both sides. There are no particular restrictions on the resin used in the sealant film, and known polyolefin resins such as polyethylene resins and polypropylene resins can be used. The polyethylene resin may be an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, and any of ultra-low density polyethylene, low density polyethylene, linear low density polyethylene, medium density polyethylene, or high density polyethylene can be used, but low density polyethylene and linear low density polyethylene are preferred in terms of heat sealability and versatility. The polypropylene resin may be a propylene homopolymer or a copolymer of propylene and an α-olefin having 2 to 20 carbon atoms. A propylene-ethylene random copolymer is preferred from the viewpoint of heat sealability and versatility. These may be used individually or as a mixture of two or more. Furthermore, from the perspective of reducing environmental impact, recycling polyolefin resin compositions (R2) from molded articles (M0) containing polyethylene and polypropylene made from bioethanol and bioisopropanol derived from biomass raw materials is of great significance in promoting a circular economy and the formation of a circular society. Furthermore, for the purpose of easy opening, if the layer containing polyethylene resin and / or polypropylene resin is 100% by mass, it may also contain 0 to 50% by mass of polybutene resin, polystyrene resin, etc.

[0050] Sealant films are used in the majority of packaging molded products (laminated bodies, laminated films), and separating and reusing these polyolefin resins from the molded product (M0) is also an important matter in forming a circular economy and a circular society. Reusing polyolefin resin compositions (R2) obtained by separating and regenerating them separately, similar to the polyamide resin composition (R1) obtained by separating and regenerating from the molded product (M0), will lead to a significant improvement in the recycling rate of the molded product (M0) (laminated bodies, laminated films).

[0051] When the sealant film is a multilayer film, co-extruded multilayer films are frequently used, and in addition to the polyolefin resin layer, layers containing polyamide resins such as aliphatic polyamide, aromatic polyamide, and semi-aromatic polyamide, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyvinyl alcohol resin, ethylene vinyl alcohol resin, polyvinyl chloride resin, acrylic resin, thermoplastic elastomer, and acid-modified products thereof can be arranged, and the polyolefin resin layer is arranged on at least one surface of the sealant film. There are no particular restrictions on the thickness of each sealant film, but 3 to 100 μm is preferred, and 5 to 80 μm is more preferred.

[0052] (Additives) A molded article (M0) containing a polyamide resin layer may contain known additives in addition to the main resin material. Examples include fillers, lubricants, antiblocking agents, antioxidants, heat stabilizers, UV absorbers, colorants, antifogging agents, mold release agents, and the like.

[0053] (adhesive layer) A molded article (M0) containing at least one polyamide resin layer may be, for example, a laminate (laminated film) prepared by laminating a film containing one polyamide resin layer with another film such as a sealant film using a known dry lamination method. The adhesive can be a known dry lamination adhesive, and may be a one-component or two-component system, or it may also be used with a crosslinking agent added. From the viewpoint of interlayer adhesion, a polyester-based adhesive is preferred, and a two-component system consisting of a polyol and a crosslinking agent is preferred. Examples of polyols include polyester-based, polyether-based, and acrylic-based polyols, and examples of curing agents and crosslinking agents include aromatic isocyanates, aliphatic isocyanates, carbodiimides, and epoxy-based agents. Furthermore, from the viewpoint of ease of dissolution by the release agent (A) described later, an adhesive consisting of a polyester-based polyurethane system formed by compounding a polyester-based polyol and an aliphatic isocyanate is preferred. There are no particular restrictions on the thickness of the adhesive layer, but it is generally preferred to be 1 to 10 μm, and more preferably 2 to 5 μm.

[0054] The polyamide resin composition (R1) and polyolefin resin composition (R2) of the present invention can be obtained from resin compositions separated from a molded article (M0) using a release agent (A). <Removal agent (A)> The stripping agent (A) used in the present invention contains a polar solvent, a quaternary ammonium salt, and water. Examples of polar solvents include diethylene glycol monobutyl ether, isopropanol, N-methyl-2-pyrrolidone, dimethylformamide, dimethyl sulfoxide, and benzyl alcohol. These may be used individually or in combination of two or more. Examples of quaternary ammonium salts include dimethylbis(2-hydroxyethyl)ammonium hydroxide, monomethyltris(2-hydroxyethyl)ammonium hydroxide, trimethyl-2-hydroxyethylammonium hydroxide, and tetraalkylammonium hydroxides (such as tetramethylammonium hydroxide) whose pH in a 1% aqueous solution is 11.5 or higher.

[0055] The release agent (A) can dissolve the adhesive layer, the polyester resin layer and / or film such as polyethylene terephthalate, the ethylene vinyl alcohol resin layer and / or film, the printed layer, etc., of the molded article (M0). On the other hand, the polyamide resin layer and / or film, and the polyolefin resin layer and / or film are not dissolved by the release agent (A). Dissolution and separation using the release agent (A) does not involve the use of acid or high-temperature heating processes exceeding 100°C. Therefore, hydrolysis and degradation of the polyamide resin constituting the molded body (M0) are suppressed, and a polyamide resin composition (R1) and a polyolefin resin composition (R2) can be obtained. These can then be reused in molded bodies, similar to new polyamide resins and polyolefin resins referred to as virgin pellets.

[0056] <Method for producing resin compositions (R1) and (R2)> The procedure and method for obtaining a polyamide resin composition (R1) and a polyolefin resin composition (R2) by separating and regenerating a molded body (M0) using a release agent (A) is as follows. First, the molded body (M0) is cut in a crusher to produce fluff. Next, the fluff is immersed in and stirred with release agent (A) under normal pressure and heated conditions to dissolve the adhesive layer, printing layer, various resins, etc. The temperature and time for immersion and stirring are preferably 1 to 5 days, more preferably 2 to 4 days, under conditions of 20°C or higher and less than 60°C. Under conditions of 60°C or higher, it is preferably 1 to 5 hours, more preferably 2 to 4 hours. Subsequently, the resin composition (R0) that is insoluble in the release agent (A) is removed and washed with water or the like to remove the release agent (A). The resin composition (R0) contains a polyamide resin fluff and a polyolefin resin fluff that are insoluble in the release agent (A). Subsequently, for example, using water, the resin composition (R0) is stirred in water at 25°C and then allowed to stand. This process utilizes the difference in specific gravity between the polyamide resin (specific gravity 1.00-1.25) and the polyolefin resin (specific gravity 0.870-0.970) to separate the two (by specific gravity difference), and then dries under conditions such as hot air. Furthermore, if the molded product (M0) contains multiple types of polyamide resins, it is separated together as polyamide resin fluff. Similarly, if it contains multiple types of polyolefin resins, it is separated together as polyolefin resin fluff.

[0057] The separated polyamide resin fluff can be melt-extruded at 200-300°C using an extruder, and recycled pellets made of polyamide resin composition can be produced using known methods such as the strand-cut method and the hot-cut method. Similarly, the separated polyolefin resin fluff can be melt-extruded at 100-250°C to produce recycled pellets made of polyolefin resin composition.

[0058] Furthermore, both the polyamide resin fluff separated and separated using the release agent (A), and the recycled pellets produced using said fluff, are referred to as the polyamide resin composition (R1). Similarly, both the polyolefin resin fluff separated and fractionated using the release agent (A), and the recycled pellets produced using said fluff, are referred to as the polyolefin resin composition (R2).

[0059] The pulverization of the molded body (M0) (laminated body, laminated film) can be carried out using a known pulverizer such as a film pulverizer. It is preferable that excessive heat is not applied to the molded body or fluff due to friction between the inside of the device and the molded body or fluff, so that the molded body and pulverized material (fluff) do not deteriorate due to heat. There are no particular restrictions on the shape of the fluffs; they are generally irregular or polygonal. However, to prevent the fluffs from becoming entangled, it is preferable that their length and width are roughly equal, and a roughly rectangular shape is more preferable. The size of the fluff is preferably 20 mm or less, and more preferably 15 mm or less, from the viewpoint of allowing the release agent (A) for dissolution and separation to penetrate into the interior of the molded body (M0) from the cut end face of the molded body (M0). Furthermore, from the viewpoint of preventing fluff from accumulating during the cutting and crushing process and facilitating separate recovery by specific gravity difference in subsequent processes, the size of the fluff is preferably 3 mm or more, and more preferably 5 mm or more. Particularly preferably it is 8 to 12 mm. [Examples]

[0060] The present invention will be described in detail below using examples, but it is not limited to these examples. <Raw materials, various films> The compositions of the various films used in the examples, comparative examples, and reference examples are as follows. Polyamide 6 is abbreviated as "PA6", polymetaxylylene adipamide as "MXD6", low-density polyethylene as "PE", and dry laminating adhesive as "ad". "△△μm" represents the thickness of the layer or film. Furthermore, the melting points of the resins were measured in accordance with JIS K7121:2012, with PA6 at 215°C, MXD6 at 237°C, and PE at 113°C.

[0061] (Polyamide resin film) a1: PA6 (5.5 μm) / MXD6 (4.0 μm) / PA6 (5.5 μm), co-extruded biaxially oriented film, single-sided corona discharge treatment. a2: PA6 (10.5 μm) / MXD6 (4.0 μm) / PA6 (10.5 μm), co-extruded biaxially oriented film, single-sided corona discharge treatment.

[0062] (Sealant film) • p1; PE (60μm), unstretched film, single-sided corona discharge treatment, "Toyobo Co., Ltd. Rix® Film L4102" • p2; PE (40 μm), unstretched film, single-sided corona discharge treatment, "Toyobo Co., Ltd. Rix® Film L4102"

[0063] (Dry laminating adhesive) • A two-component system of polyester polyol and aliphatic isocyanate was used, with a molar equivalent ratio of hydroxyl groups to isocyanate groups of 1.0. Ethyl acetate was used as the diluent, and the thickness after drying was 3 μm.

[0064] <Preparation of polyamide resin composition (R1) and polyolefin resin composition (R2)> Molded articles and fluffs were prepared according to the procedures of the following examples, comparative examples, and reference examples to obtain resin compositions (R1) and (R2), and then evaluated as described below. (Example 1) A polyamide resin film a1, which had gravure printing in five colors (black, blue, red, yellow, and white) applied to its corona discharge-treated surface, was placed opposite the corona discharge-treated surface of a sealant film p1, and a molded body (M0) (laminated film) was obtained by applying a dry laminating adhesive (ad). The obtained molded body (M0) was crushed using a film cutter to produce roughly rectangular or polygonal fluffs with a long side of 10 mm.

[0065] The separation of the recycled resin composition from the fluff of the molded body (M0) was carried out using a release agent (A) with the composition of 70 parts N-methyl-2-pyrrolidone, 5 parts dimethylbis(2-hydroxyethyl)ammonium hydroxide, and 25 parts water, following the procedure below. 50 g of fluff and 2,000 g of release agent (A) were mixed, and immersion and stirring were carried out for 3 hours at atmospheric pressure and a temperature of 80°C. After that, the fluff insoluble in release agent (A) was removed and washed with water. Then, using a water tank filled with water, the fluff was separated into fluff with a specific gravity of 1.00 or less and fluff with a specific gravity greater than 1.00 under conditions of 25°C. After that, each fluff was dried with air at 60°C. A recycled resin composition of polyolefin-based resin composition (R2) was obtained as fluff with a specific gravity of less than 1.00, and a recycled resin composition of polyamide-based resin composition (R1) was obtained as fluff with a specific gravity of 1.00 or more.

[0066] (Example 2) A polyamide resin film a2, which had gravure printing in four colors (blue, red, yellow, and white) applied to its corona discharge-treated surface, was placed opposite the corona discharge-treated surface of a sealant film p2, and a molded body (M0) (laminated film) was obtained by applying a dry laminating adhesive. The obtained molded body (M0) was crushed using a film cutter to produce roughly rectangular or polygonal fluffs with a long side of 10 mm.

[0067] The recycled resin composition was separated from the fluff of the molded article (M0) in the same manner as in Example 1, to obtain a recycled resin composition of polyolefin-based resin composition (R2) as fluff with a specific gravity of less than 1.00, and a recycled resin composition of polyamide-based resin composition (R1) as fluff with a specific gravity of 1.00 or more.

[0068] <Fabrication of polyamide resin molded product (M1)> (Example 3) Using a Toyo Seiki Laboplast Mill 4C150, each component was mixed according to the proportions shown in Table 3. The mixture was kneaded at a screw rotation speed of 50 rpm, 240°C, and for 5 minutes in a nitrogen atmosphere. The resulting mixture was heated on a hot plate preheated to 240°C at a rate of 50 kg / cm³. 2 A 200 μm polyamide resin molded body (M1) was fabricated by hot pressing under pressure for 8 minutes, followed by water cooling after the pressure was released.

[0069] (Example 4) Using a Toyo Seiki Laboplast Mill 4C150, each component was blended according to the mixing ratios shown in Table 3. A polyamide resin molded article (M1) was prepared in the same manner as in Example 3, except that it contained 40% by mass of R1 obtained in Example 2.

[0070] (Example 5) Using a Toyo Seiki Laboplast Mill 4C150, each component was blended according to the mixing ratios shown in Table 3. A polyamide resin molded article (M1) was prepared in the same manner as in Example 3, except that it contained 100% by mass of R1 obtained in Example 2.

[0071] (Reference example 1) Using a Toyo Seiki Laboplast Mill 4C150, each component was blended according to the mixing ratios shown in Table 3. A polyamide resin molded article was prepared in the same manner as in Example 3, except that it contained 100% by mass of PA.

[0072] <Fabrication of polyolefin resin molded articles (M2)> (Example 6) Using a Toyo Seiki Laboplast Mill 4C150, each component was mixed according to the proportions shown in Table 3. The mixture was kneaded at a screw rotation speed of 50 rpm, 220°C, and for 5 minutes in a nitrogen atmosphere. The resulting mixture was heated on a hot plate preheated to 220°C at a rate of 50 kg / cm³. 2 A 200 μm polyolefin resin molded article (M2) was fabricated by hot pressing under pressure for 8 minutes, followed by water cooling after the pressure was released.

[0073] (Reference example 2) Using a Toyo Seiki Laboplast Mill 4C150, each component was blended according to the mixing ratios shown in Table 3. A polyolefin resin molded article was prepared in the same manner as in Example 6, except that it contained 100% by mass of PE.

[0074] <Rating> The recycled resin compositions obtained in Examples 1 and 2 were evaluated as follows and summarized in Table 1. In addition, the polyamide resin films a1 and a2 and sealant films p1 and p2 used in Examples 1 and 2 were also evaluated individually for comparison with the recycled resin compositions, with their chemiluminescence integrated value, mass-average molecular weight, and yellowness b*.

[0075] (Separation of recycled resin composition) Compositional analysis was performed using Fourier transform infrared absorption spectroscopy, and the spectra were compared to standard spectra. Table 1 indicates whether or not a clear separation was achieved between the separated and regenerated polyamide resin composition (R1) and the polyolefin resin composition (R2).

[0076] (Preparation of resin composition powder) The polyamide resin composition (R1) and polyolefin resin composition (R2) obtained in Examples 1 and 2, as well as the individual polyamide resin films a1 and a2, and sealant films p1 and p2, were each subjected to two cycles of [cooling for 5 minutes - grinding for 5 minutes] using a cryogenic pulverizer manufactured by Nippon Analytical Engineering Co., Ltd., to obtain a powder.

[0077] (Integrated chemiluminescence value of polyamide resin composition (R1)) In accordance with JIS K7351:2018, a chemiluminescence analyzer was used to measure the cumulative chemiluminescence (counts) during a period of 60 minutes after heating 100 mg of powdered polyamide resin composition (R1) to a uniform thickness in a 20 mm diameter aluminum cup under a nitrogen gas atmosphere, from 50°C to 150°C at a rate of 10°C / min. The cumulative chemiluminescence was measured. The background value was also measured and subtracted to obtain the cumulative chemiluminescence value, which is the sum of the chemiluminescence over the measured temperature and time range.

[0078] (Integrated chemiluminescence value of polyolefin resin composition (R2)) The integrated chemiluminescence values ​​of the polyolefin resin composition (R2) were determined in the same manner as for the polyamide resin composition (R1), except that the temperature conditions of the chemiluminescence analyzer were increased from 50°C to 200°C at a rate of 15°C / min and held at 200°C for 60 minutes.

[0079] (Integrated chemiluminescence values ​​of a1, a2, p1, and p2) The polyamide resin films a1 and a2, and sealant films p1 and p2 used in Examples 1 and 2 were also measured individually to compare with the recycled resin composition, and their chemiluminescence integral values ​​were similarly measured and summarized in Table 2. Note that the measurement method for polyamide resin films a1 and a2 followed the method for measuring the chemiluminescence integral value of the polyamide resin composition (R1), while the measurement method for sealant films p1 and p2 followed the method for measuring the chemiluminescence integral value of the polyolefin resin composition (R2).

[0080] (Mass-average molecular weight of polyamide resin composition (R1)) Dichloromethane and trifluoroacetic anhydride were added to a polyamide resin composition (R1) and stirred at room temperature to derivatize (acylate). Subsequently, the mixture was stirred and dried to solidify under conditions of 40°C. Immediately after derivatization, the solidified product, which had not yet formed a gel, was dissolved with the eluent tetrahydrofuran. Within 10 minutes, the unswollen liquid was analyzed using gel permeation chromatography with an RI (suggestive refraction) detector under the conditions of a concentration of approximately 10 mg / 3.4 ml, an injection volume of 100 μL, a TSKgel Guard column, and a flow rate of 1.0 mL / min. The mass-average molecular weight was determined in terms of standard polystyrene.

[0081] (Mass-average molecular weight of polyolefin resin composition (R2)) 10 mg of polyolefin resin composition (R2) was dissolved in 10 g of o-dichlorobenzene with 0.5 g / L BHT added at 135°C. Then, using a high-temperature GPC system HLC-8321GPC / HT manufactured by Tosoh Corporation, the mixture was processed using a column TSKgel guardcolumn HHR(30)HT (7.5 mm). 2 ID×7.5cmL)+TSKgel GMHHR-H(20)HT(7.8mm 2 A sample size of ID × 30 cmL × 3 was used. Polystyrene was used as the standard sample, and the mass-average molecular weight (Mw) was determined under conditions of 135°C. The molecular weight was also converted from a general-purpose calibration curve using a calibration curve created with the standard polystyrene sample, and then converted to polyethylene equivalent.

[0082] (Yellowness of polyamide resin composition (R1) and polyolefin resin composition (R2)) Powdered polyamide resin composition (R1) and polyolefin resin composition (R2) were placed in a 0.04 mm thick, colorless, transparent resealable bag manufactured by Askul, and the yellowness b* was measured using a simple spectrophotometer NF333 manufactured by Nippon Denshoku Industries, in accordance with JIS Z8722:2009.

[0083] For the molded bodies (M1) and (M2) obtained in Actual Examples 3-6 and Reference Examples 1 and 2, the chemiluminescence integrated value and yellowness b* were measured for M1 in the same manner as for R1, and for M2 in the same manner as for R2, and the results are summarized in Table 3. Furthermore, the tensile breaking strength, tensile breaking elongation, and fracture energy were evaluated according to the following criteria and summarized in Table 3.

[0084] (Tensile test) Measurements were taken in accordance with JIS K7129:1999. A 6mm wide dumbbell-shaped test specimen was tested with a grip distance of 80.0mm and a test speed of 50mm / min to measure the tensile breaking strength and tensile breaking elongation. Polyamide resin molded articles (M1) were deemed acceptable if they had a tensile strength of 50MPa or more and a tensile breaking elongation of 200% or more, while polyolefin resin molded articles (M2) were deemed acceptable if they had a tensile strength of 10MPa or more and a tensile breaking elongation of 150% or more.

[0085] (Hydroshot impact test) In accordance with JIS K7211-2:2006, the fracture energy was calculated using a Shimadzu HTM-1 hydroshot impact tester. The test specimen was fixed with clamps, and the measurement was performed at a test speed of 3 m / sec, with a punching jig of 1 / 2 inch diameter, a striker tip diameter of 1 / 2 inch diameter, a punching support base of 50 mm diameter, and in a 23°C atmosphere. Polyamide resin molded articles (M1) were deemed acceptable if their fracture energy was 1.5 J or higher, and polyolefin resin molded articles (M2) were deemed acceptable if their fracture energy was 0.5 J or higher.

[0086] [Table 1]

[0087] [Table 2]

[0088] [Table 3]

[0089] <Polyamide resin composition (R1), polyolefin resin composition (R2)> In Examples 1 and 2, the adhesive layer for dry lamination dissolved, and if there was a printed layer, the printed layer dissolved or peeled off, allowing for clear separation and acquisition of the separated and regenerated polyamide resin composition (R1) and polyolefin resin composition (R2). PA6 and MXD6, which constituted the polyamide resin film a1 in Examples 1 and 2, were obtained as a polyamide resin film composition (R1) containing both.

[0090] The polyamide resin composition (R1) obtained in Example 1 had a chemiluminescence integrated value of 16,891,852 counts, a mass-average molecular weight of 55,300, and a yellowness b* of 2.0. It showed only slight oxidative degradation and was free from contamination with other resins, making it suitable for use as a recycled raw material in films, packaging, and the like.

[0091] The polyolefin resin composition (R2) obtained in Example 1 had a chemiluminescence integrated value of 9,966,109 counts, showed only slight oxidative degradation, and contained no other resins, making it suitable for use as a recycled raw material in films, packaging, etc.

[0092] The polyamide resin composition (R1) obtained in Example 2 had a chemiluminescence integrated value of 3,545,484 counts, a mass-average molecular weight of 73,500, and a yellowness b* of 8.94. It showed only slight oxidative degradation and was free from contamination with other resins, making it suitable for use as a recycled raw material in films, packaging, and the like.

[0093] The polyolefin resin composition (R2) obtained in Example 2 had a chemiluminescence cumulative value of 794,987 counts, a mass-average molecular weight of 83,308, and a yellowness b* of 1.21. It showed only slight oxidative degradation and was free from contamination with other resins, making it suitable for use as a recycled raw material in films, packaging, and the like.

[0094] <Polyamide resin molded product (M1), polyolefin resin molded product (M2)> The polyamide resin compositions (M1) obtained in Examples 3 to 5 had chemiluminescence integrated values ​​and yellowness b* within the specified range, exhibited minimal oxidative degradation, and had tensile breaking strength, tensile breaking elongation, and fracture energy above the desired level, making them suitable as packaging materials containing recycled raw materials.

[0095] The polyolefin resin composition (M2) obtained in Example 6 had a chemiluminescence integrated value and yellowness b* within the specified range, showed only slight oxidative degradation, and had tensile breaking strength, tensile breaking elongation, and fracture energy that were above the desired level, making it suitable as a packaging material containing recycled raw materials. [Industrial applicability]

[0096] The present invention makes it possible to obtain a reusable recycled polyamide resin composition from a molded article, and also a reusable recycled polyolefin resin composition. Since these recycled resin compositions can be obtained without using acids or high-temperature processes exceeding 100°C, degradation can be suppressed, making them effective for the reuse of molded articles such as films. The ability to recycle large quantities of polyamide and polyolefin resins from dry-laminated laminated films, which are widely used in packaging materials, greatly contributes to the creation of a circular economy and a circular society.

Claims

1. The separation product from a molded article (M0) comprising at least an adhesive layer and a polyolefin resin layer using a release agent (A) containing a polar solvent, a quaternary ammonium salt, and water, The adhesive layer contains a polyester-based adhesive. The mass-average molecular weight is between 40,000 and 200,000. In accordance with JIS K7351:2018, the cumulative chemiluminescence value during heating from 50°C at a rate of 15°C / min and holding at 200°C for 60 minutes under a nitrogen gas atmosphere is 700,000 to 15,000,000 counts. Polyolefin resin composition (R2).

2. The polyolefin resin composition (R2) according to claim 1, wherein the separated product from the molded body (M0) is a separated product obtained at a temperature of 100°C or lower.

3. The polyolefin resin composition (R2) according to claim 1 or 2, wherein the polyester adhesive is a two-component system comprising a polyester polyol and an aliphatic isocyanate.

4. A polyolefin resin composition (R2) according to any one of claims 1 to 3, which is fluff or pellets.

5. A polyolefin resin composition (R2) according to any one of claims 1 to 4, wherein the yellowness b* is 1.0 or more and 10.0 or less.

6. The polyolefin resin composition (R2) according to any one of claims 1 to 5, further comprising a product separated from a molded article (M0) containing a polyamide resin layer.

7. A polyolefin resin molded article (M2) having a content of the polyolefin resin composition (R2) described in any one of claims 1 to 6 of 1% by mass or more and 100% by mass or less.

8. The polyolefin resin molded article (M2) according to claim 7, wherein the shape is a film or a sheet.

9. A polyolefin resin molded article (M2) according to claim 7 or 8, wherein the yellowness b* is 1.0 or more and 10.0 or less.

10. The polyolefin resin molded article (M2) according to any one of claims 7 to 9, wherein when the polyolefin resin molded article (M2) is 100% by mass, it further contains an antioxidant and / or a heat stabilizer in an amount of 1% by mass or more and 20% by mass or less.

11. A packaging body made using a polyolefin resin molded article (M2) according to any one of claims 7 to 10.

12. A fluff or pellet comprising a separated product from a molded article consisting of a laminate comprising at least a polyolefin resin layer and an adhesive layer, by a release agent (A) containing a polar solvent, a quaternary ammonium salt, and water, wherein the fluff or pellet is made of a polyolefin resin composition comprising at least one polyolefin resin, and the mass-average molecular weight of the polyolefin resin composition is 40,000 or more and 200,000 or less. The adhesive layer contains a polyester-based adhesive. In accordance with JIS K7351:2018, the cumulative chemiluminescence value during heating from 50°C at a rate of 15°C / min and holding at 200°C for 60 minutes under a nitrogen gas atmosphere is 700,000 to 15,000,000 counts. Polyolefin resin fluff or pellets.

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