Recycled polyolefin resin, method for producing recycled polyolefin resin, and molded article

Abstract

To provide a recycled polyolefin resin that exhibits comparatively stable processability and in which degradation caused by oxidation is comparatively restrained, a method for producing the recycled polyolefin resin and a molded article.SOLUTION: A recycled polyolefin resin comprises a polyolefin resin, a peroxide, and an antioxidant, wherein a melt flow rate measured at 230°C under a load of 2.16 kg is 0.1 g / 10 min or more and 23 g / 10 min or less, a theoretical active oxygen amount is 1.0×10-5 mass% or more and 1.8×10-2 mass% or less with respect to 100 mass% of the polyolefin resin, and a content of the antioxidant is 0.1 mass% or more and 4.0 mass% or less with respect to 100 mass% of the polyolefin resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a recycled polyolefin resin, a method for producing the recycled polyolefin resin, and a molded article. [Background technology]

[0002] Molded articles containing polyolefin resins are used in industrial parts such as automobile parts and electrical parts, daily necessities, miscellaneous goods, etc. In recent years, material recycling of polyolefin resins has been studied from the viewpoints of reducing environmental load, achieving carbon neutrality, etc.

[0003] Meanwhile, polyolefin-based recycled resins obtained by material recycling are required to have stable processability. To ensure stable processability, a method has been proposed in which the fluidity of polyolefin-based recycled resins is adjusted by adding peroxides, for example (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-277366 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the polyolefin-based recycled resin of Patent Document 1 has a problem in that the polyolefin-based recycled resin is easily oxidized and deteriorated due to the peroxides remaining in the polyolefin-based recycled resin. Therefore, there is a need to develop a polyolefin-based recycled resin that ensures stable processability while suppressing deterioration in quality.

[0006] Therefore, an object of the present invention is to provide a polyolefin-based recycled resin that has relatively stable processability and is relatively inhibited from deteriorating due to oxidation, a method for producing the polyolefin-based recycled resin, and a molded article. [Means for solving the problem]

[0007] The polyolefin-based recycled resin according to the present invention is Contains a polyolefin resin, a peroxide, and an antioxidant, The melt flow rate measured at 230°C under a 2.16 kg load is 0.1 g / 10 min or more and 23 g / 10 min or less, The theoretical amount of active oxygen is 1.0 × 10 relative to 100% by mass of the polyolefin resin. -5 Mass% or more 1.8×10 -2 % by mass or less, The content of the antioxidant is 0.1% by mass or more and 4.0% by mass or less with respect to 100% by mass of the polyolefin resin.

[0008] The method for producing a polyolefin-based recycled resin according to the present invention comprises: A method for producing a polyolefin-based recycled resin by carrying out a kneading step of kneading the polyolefin-based resin, In the kneading step, the peroxide is further added.

[0009] The molded body according to the present invention is The polyolefin-based recycled resin is used. [Effects of the Invention]

[0010] According to the present invention, there are provided a polyolefin-based recycled resin that has relatively stable processability and is relatively inhibited from deteriorating due to oxidation, a method for producing the polyolefin-based recycled resin, and a molded article. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0012] [Recycled polyolefin resin] The polyolefin-based recycled resin according to this embodiment contains a polyolefin-based resin, and the content of the polyolefin-based resin is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on 100% by mass of the polyolefin-based recycled resin.

[0013] In the polyolefin-based recycled resin according to this embodiment, the polyolefin-based resin is preferably polypropylene.

[0014] The polypropylene may be recycled polypropylene or virgin polypropylene. In this specification, "recycled xxx" means that the polypropylene has been processed, such as molded, or used for some end use, and then recovered and reused. "Virgin xxx" means that the polypropylene has not been molded into a product such as an automobile or its parts, and has not been used for some end use.

[0015] The recycled polypropylene may be recycled polypropylene recovered from the market, or recycled polypropylene recovered in-process.

[0016] Recycled polypropylene collected from the market is made from polypropylene molded bodies used in the market. Recycled polypropylene collected in-process is made from the propylene material generated during the manufacturing process of polypropylene molded bodies, and the resulting molded bodies. Examples of polypropylene molded bodies include automobile parts, packaging containers (e.g., food retort pouches, refill pouches, detergent bottles), housings for household electrical appliances, office supplies (e.g., trays), and household items (e.g., contact lens cases). Examples of automobile parts include automobile interior parts (e.g., instrument panels, door trims), automobile exterior parts (e.g., bumpers), and other automobile parts (e.g., battery cases).

[0017] Polypropylene can be produced by a known polymerization method using a known olefin polymerization catalyst.

[0018] Examples of polymerization catalysts include Ziegler-type catalyst systems, Ziegler-Natta-type catalyst systems, catalyst systems consisting of a Group 4 transition metal compound having a cyclopentadienyl ring and an alkylaluminoxane, catalyst systems consisting of a Group 4 transition metal compound having a cyclopentadienyl ring, a compound that reacts with it to form an ionic complex, and an organoaluminum compound, and catalyst systems in which inorganic particles such as silica or clay minerals are supported and modified with catalytic components such as a Group 4 transition metal compound having a cyclopentadienyl ring, a compound that forms an ionic complex, or an organoaluminum compound. The polymerization catalyst may also be a prepolymerization catalyst system prepared by prepolymerizing ethylene or an α-olefin in the presence of the above catalyst system.

[0019] From the viewpoint of improving productivity, polypropylene may be produced by a method in which a plurality of polymerization steps are carried out in multiple stages (multistage polymerization method). The multistage polymer obtained by such a multistage polymerization method may contain at least two types of polypropylene, or may contain one type of polypropylene.

[0020] The intrinsic viscosity of the polypropylene is preferably 0.5 dl / g or more and 5.0 dl / g or less, and more preferably 1.0 dl / g or more and 4.0 dl / g or less.

[0021] The intrinsic viscosity of polypropylene is measured by the following method. Using an Ubbelohde viscometer, the reduced viscosity of three samples with concentrations of 0.1 g / dL, 0.2 g / dL, and 0.5 g / dL is measured. The intrinsic viscosity is calculated using the calculation method described in page 491 of the reference book "Polymer Solutions, Polymer Experiments 11" (published by Kyoritsu Publishing Co., Ltd. in 1982). That is, the reduced viscosity is plotted against the concentration, and the intrinsic viscosity is calculated by extrapolating the concentration to zero. Tetralin is used as the solvent, and the measurement is carried out at a temperature of 135°C.

[0022] The polyolefin-based recycled resin according to this embodiment has a limiting viscosity of polypropylene within the above-mentioned range, and therefore has stable processability and is further prevented from deteriorating due to oxidation.

[0023] The polyolefin-based recycled resin according to this embodiment preferably has a polypropylene content of 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to 100% by mass of the polyolefin-based recycled resin.

[0024] The polyolefin-based recycled resin according to this embodiment has a polypropylene content within the above-mentioned range, and therefore has stable processability and is further prevented from deteriorating due to oxidation.

[0025] The recycled polyolefin resin according to this embodiment contains a peroxide. Examples of peroxides that can be used include hydrogen peroxide and organic peroxides. Examples of organic peroxides include dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, 1,3-bis(t-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(t-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butyl peroxybenzoate, t-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and t-butylcumyl peroxide. These may be used alone or in combination of two or more. Among these, the organic peroxide is preferably 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane from the viewpoint of ease of handling.

[0026] The content of the peroxide is 8.0 × 10 relative to 100% by mass of the polyolefin resin. -5Mass% or more 1.8×10 -1 % by mass or less, preferably 8.0 × 10 -3 Mass% or more 1.5×10 -1 % by mass or less, and more preferably 4.0 × 10 -2 Mass% or more 1.0×10 -1 It is less than % by mass.

[0027] The polyolefin-based recycled resin according to this embodiment contains an antioxidant. Examples of the antioxidant include phenol-based antioxidants and phosphorus-based antioxidants. The antioxidants may be used alone or in combination of two or more.

[0028] In the recycled polyolefin resin according to this embodiment, the antioxidant is preferably a phenol-based antioxidant or a phosphorus-based antioxidant.

[0029] The polyolefin-based recycled resin according to this embodiment has stable processability and further suppresses deterioration due to oxidation because the antioxidants are a phenol-based antioxidant and a phosphorus-based antioxidant.

[0030] Examples of phenolic antioxidants include 2,6-di-t-butyl-4-methylphenol (BHT), n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (trade name: Irganox 1076, manufactured by BASF Japan Ltd.), pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (trade name: Irganox 1010, manufactured by BASF Japan Ltd.), 1,3,5-tris(3,5-di-t-butyl- 4-hydroxybenzyl) isocyanurate (trade name: Irganox 3114, manufactured by BASF Japan Ltd.), 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (trade name: Sumilizer GA80, manufactured by Sumitomo Chemical Co., Ltd.), and the like.

[0031] Examples of phosphorus-based antioxidants include distearyl pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl)phosphite (trade name: Irgafos168, manufactured by BASF Japan Ltd.), bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, tetrakis(2,4-di-t-butylphenyl)-4,4′-biphenylene diphosphite, bis(2-t-butyl-4-methylphenyl)pentaerythritol diphosphite, and 2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzo[d,f][1,3,2]dioxaphosphepine (trade name: Sumilizer GP, manufactured by Sumitomo Chemical Co., Ltd.).

[0032] In the polyolefin-based recycled resin according to this embodiment, the content of the antioxidant is 0.1% by mass to 4.0% by mass, preferably 0.5% by mass to 3.0% by mass, and more preferably 1.0% by mass to 2.5% by mass, relative to 100% by mass of the polyolefin-based resin. When two or more types of antioxidants are used, the content of the antioxidants is the total content of these antioxidants.

[0033] The polyolefin-based recycled resin according to this embodiment has an antioxidant content within the above-mentioned range, so that the resin has stable processability and is prevented from deteriorating due to oxidation.

[0034] The recycled polyolefin resin according to this embodiment may further contain a neutralizing agent. Examples of neutralizing agents include calcium stearate, synthetic hydrotalcite, alkaline earth metal oxides, and alkaline earth metal hydroxides. The neutralizing agents may be used alone or in combination of two or more.

[0035] The content of the neutralizing agent may be 0.001% by mass or more and 0.10% by mass or less, and preferably 0.005% by mass or more and 0.05% by mass or less, relative to 100% by mass of the polyolefin resin.

[0036] In addition to the above components, the polyolefin-based recycled resin according to this embodiment may further contain an antistatic agent, a weathering agent, a lubricant, an antiblocking agent, an antifogging agent, a drip-proofing agent, a pigment, a filler, and the like.

[0037] The polyolefin-based recycled resin according to this embodiment has a theoretical active oxygen content of 1.0 × 10 relative to 100% by mass of the polyolefin-based resin. -5 Mass% or more 1.8×10 -2 mass% or less, preferably 1.0 × 10 -3 Mass% or more 1.5×10 -2 % by mass or less, and more preferably 5.0 × 10 -3 Mass% or more 1.0×10 -2In this specification, the term "theoretical amount of active oxygen" is an index showing the number of free radicals generated from the peroxide blended together with the polyolefin resin.

[0038] The theoretical active oxygen amount is calculated by the following general formula (1): The theoretical active oxygen amount and peroxide content in formula (1) are values ​​when the mass of the polyolefin resin is 100 mass%, the number 16 in formula (1) represents the atomic weight of oxygen, and the peroxide bond in formula (1) refers to an oxygen-oxygen bond in the peroxide. Theoretical active oxygen content (mass%) = peroxide content (mass%) × (16 × number of peroxide bonds per peroxide molecule) / molecular weight of peroxide (1)

[0039] The polyolefin-based recycled resin according to this embodiment has a theoretical active oxygen content within the above-mentioned range, and therefore exhibits stable processability while suppressing deterioration due to oxidation.

[0040] The polyolefin-based recycled resin according to this embodiment has a melt flow rate, measured at 230°C under a load of 2.16 kg, of 0.1 g / 10 min or more and 23 g / 10 min or less, preferably 0.5 g / 10 min or more and 20 g / 10 min or less, and more preferably 1.0 g / 10 min or more and 18 g / 10 min or less.

[0041] The melt flow rate of polyolefin-based recycled resin is measured at a temperature of 230°C and a load of 2.16 kg according to Method A specified in JIS K7210-1:2014. The melt flow rate of polyolefin-based recycled resin is measured on shredded press-molded film. The press-molded film is produced by preheating raw polyolefin-based recycled resin material containing polyolefin-based resin at 230°C for 5 minutes in a heat press molding machine, increasing the pressure to 10 MPa, holding the pressure for 5 minutes, and then cooling at 30°C for 5 minutes. The press-molded film is produced so that its thickness is 100 to 150 μm.

[0042] The thickness of the press-molded film can be measured using a contact-type film thickness meter in accordance with Method A described in JIS K7130-1999.

[0043] The polyolefin-based recycled resin may be in the form of, for example, pellets, sheets, rods, or the like.

[0044] The polyolefin-based recycled resin according to this embodiment contains a polyolefin-based resin, a peroxide, and an antioxidant, and has a melt flow rate of 0.1 g / 10 min or more and 23 g / 10 min or less, measured at 230°C under a load of 2.16 kg, and a theoretical active oxygen content of 1.0 × 10 relative to 100% by mass of the polyolefin-based resin. -5 Mass% or more 1.8×10 -2 By setting the antioxidant content to 0.1% by mass or more and 4.0% by mass or less relative to 100% by mass of the polyolefin resin, the polyolefin resin has relatively stable processability and is relatively inhibited from deteriorating due to oxidation.

[0045] [Manufacturing method for recycled polyolefin resin] In the method for producing a polyolefin-based recycled resin according to this embodiment, the above-described polyolefin-based recycled resin is produced by carrying out a kneading step of kneading a polyolefin-based resin.

[0046] The kneading step may be carried out using, for example, a single-screw extruder, a multi-screw extruder such as a twin-screw extruder, a roll mixer, a kneader, a Brabender plastograph, a Banbury mixer, etc. In the method for producing a polyolefin-based recycled resin according to this embodiment, the kneading step is preferably carried out using a single-screw extruder or a twin-screw extruder (hereinafter simply referred to as "extruder"). The extruder is equipped with a cylinder.

[0047] In the kneading step, a molten mixture containing a polyolefin resin may be kneaded. The molten mixture may further contain an antioxidant.

[0048] From the viewpoint of ensuring stable processability of the produced polyolefin-based recycled resin, the method for producing polyolefin-based recycled resin according to this embodiment further includes adding the peroxide in the kneading step. In addition, the melt-kneaded product preferably further contains the peroxide.

[0049] The peroxide may be added in a state diluted with a resin, an inorganic compound, etc. Examples of the resin include polypropylene and polyethylene, and examples of the inorganic compound include silica.

[0050] The kneading step is carried out at a cylinder temperature set preferably between 180°C and 300°C.

[0051] The method for producing a recycled polyolefin resin according to this embodiment may further include a cooling step of cooling the molten mixture extruded by the extruder. Examples of the cooling method in the cooling step include water cooling.

[0052] The method for producing a recycled polyolefin resin according to this embodiment may include a shaping step in which the molten mixture cooled in the cooling step is processed into various shapes. The shaping step may be, for example, a pelletizing step in which the molten mixture is processed into pellets using a pelletizer.

[0053] The method for producing a polyolefin-based recycled resin according to this embodiment is a method for producing the above-mentioned polyolefin-based recycled resin by carrying out a kneading step of kneading the polyolefin-based resin, and by further adding the peroxide in the kneading step, it is possible to produce a polyolefin-based recycled resin that has relatively stable processability and in which deterioration due to oxidation is relatively suppressed.

[0054] [Molded body] The molded article according to this embodiment uses the above-mentioned recycled polyolefin resin, that is, the above-mentioned recycled polyolefin resin can be used as a material for molding to form the molded article.

[0055] Examples of the molded article include films and other resin molded articles. The molded article according to this embodiment is preferably a film. Hereinafter, the molded article according to this embodiment will be described using a film as an example.

[0056] The film can be formed by melting the above-mentioned recycled polyolefin resin and forming it into a film. A known film production method can be used as the film production method, and examples thereof include the T-die method, the inflation method, and the tubular method. The film according to this embodiment may be a single-layer film formed from the above-mentioned recycled polyolefin resin, or a multilayer film having a layer formed from the above-mentioned recycled polyolefin resin.

[0057] When the film is a single-layer film, it can be used as a sealant film. The sealant film can be laminated with a base film to form a multilayer film. Examples of the base film include biaxially stretched films using polyester resins, polyamide resins, polyolefin resins, etc. When the film is a multilayer film, the multilayer film may be formed by laminating the sealant film and the base film as described above, or may be formed by co-extrusion of the above-mentioned polyolefin-based recycled resin and another resin.

[0058] Examples of methods for producing multilayer films include a method using a feedblock die in which molten resins flowing into a die from multiple extruders are combined in layers within the die, and a method using a multi-manifold die in which molten resins flowing into a die from multiple extruders are sent to separate manifolds and combined in layers just before the lip of the die.

[0059] The use of the multilayer film is not particularly limited, and examples thereof include packaging applications. Examples of packaging applications include packaging applications for food, textiles, miscellaneous goods, heavy goods, etc. The multilayer film is preferably a multilayer film for packaging retort food. The multilayer film may also be used as a material for forming a packaging bag.

[0060] The molded article according to this embodiment uses the above-mentioned recycled polyolefin resin, and therefore has relatively stable processability and is relatively inhibited from deteriorating due to oxidation.

[0061] The present invention includes the following aspects. [1] Contains a polyolefin resin, a peroxide, and an antioxidant, The melt flow rate measured at 230°C under a 2.16 kg load is 0.1 g / 10 min or more and 23 g / 10 min or less, The theoretical amount of active oxygen is 1.0 × 10 relative to 100% by mass of the polyolefin resin. -5 Mass% or more 1.8×10 -2 % by mass or less, The content of the antioxidant is 0.1% by mass or more and 4.0% by mass or less with respect to 100% by mass of the polyolefin-based resin. Recycled polyolefin resin. [2] the polyolefin resin is polypropylene, The content of the polypropylene is 50% by mass or more relative to 100% by mass of the polyolefin-based recycled resin. [1] The polyolefin-based recycled resin described in [1]. [3] The antioxidant is a phenol-based antioxidant and a phosphorus-based antioxidant. [1] or [2]. [4] A method for producing a polyolefin-based recycled resin, comprising the steps of: kneading the polyolefin-based resin to produce the polyolefin-based recycled resin according to any one of [1] to [3]; In the kneading step, the peroxide is further added. A method for producing recycled polyolefin resin. [5] [1] to [3], using the polyolefin-based recycled resin described in any one of [1] to [3]. Molded body. [6] It is a film, [5] The molded article according to [5].

[0062] The polyolefin-based recycled resin, the method for producing the polyolefin-based recycled resin, and the molded article according to the present invention are not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. Furthermore, the configurations, methods, etc. of embodiments other than those described above may be arbitrarily adopted and combined, and the configurations, methods, etc. of one embodiment described above may be applied to the configurations, methods, etc. of other embodiments described above. [Example]

[0063] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0064] The measurement values ​​of each item were measured by the following method.

[0065] [Intrinsic viscosity (unit: dl / g)] Using an Ubbelohde viscometer, the reduced viscosity of three samples with concentrations of 0.1 g / dL, 0.2 g / dL, and 0.5 g / dL was measured. The intrinsic viscosity was calculated using the calculation method described in page 491 of the reference book "Polymer Solutions, Polymer Experiments 11" (published by Kyoritsu Publishing Co., Ltd. in 1982). That is, the reduced viscosity was plotted against the concentration, and the intrinsic viscosity was calculated by extrapolation to zero. Tetralin was used as the solvent, and the measurement was carried out at a temperature of 135°C.

[0066] [Theoretical active oxygen amount (unit: mass%)] The theoretical active oxygen amount was calculated using the following general formula (1): The theoretical active oxygen amount and peroxide content in formula (1) are values ​​when the mass of the polyolefin resin is 100 mass%, the number 16 in formula (1) represents the atomic weight of oxygen, and the peroxide bond in formula (1) refers to the oxygen-oxygen bond in the peroxide. Theoretical active oxygen content (mass%) = peroxide content (mass%) × (16 × number of peroxide bonds per peroxide molecule) / molecular weight of peroxide (1)

[0067] [Melt flow rate (MFR, unit: g / 10 min)] The melt flow rate was measured at a temperature of 230°C and a load of 2.16 kg according to Method A of JIS K7210-1:2014. For the polyolefin-based recycled resin, the melt flow rate was measured on shredded pieces of press-molded film produced by the following method. The press-molded film was produced by preheating a polyolefin-based virgin resin (described below) to 230°C for 5 minutes in a heat press molding machine, increasing the pressure to 10 MPa, holding the pressure for 5 minutes, and then cooling to 30°C for 5 minutes. The thickness of the press-molded film was 100 to 150 μm.

[0068] [Film thickness (unit: μm)] The thickness of the film was measured using a contact type film thickness meter in accordance with Method A described in JIS K7130-1999.

[0069] [Cumulative chemiluminescence intensity (unit: count / g)] The integrated chemiluminescence luminescence intensity was measured using a press-molded film prepared by the following method.

[0070] The press-molded film was produced by preheating polyolefin virgin resin or polyolefin recycled resin in a heat press molding machine at 230°C for 5 minutes, increasing the pressure to 10 MPa and holding the pressure for 5 minutes, and then cooling at 30°C for 5 minutes. The thickness of the press-molded film was 100 to 150 μm.

[0071] A measurement sample was prepared by stacking three sheets of press-molded film cut into a size of 3 cm long and 3 cm wide, and the mass of the measurement sample was measured. The measurement sample was placed in the sample chamber of a chemiluminescence measuring device (Tohoku Electronics Industry Co., Ltd. CLA-FS4) with a photomultiplier tube as a detection element that had been preheated to 150°C, and measurement of the chemiluminescence emission intensity from 300 nm to 850 nm was started under a nitrogen gas atmosphere while nitrogen gas was supplied to the sample chamber at 50 ml / min. The chemiluminescence emission intensity was measured every second. The integrated value of the chemiluminescence emission intensity from the start of measurement to 300 seconds was calculated. The integrated value was divided by the mass of the press-molded film used in the measurement to determine the integrated chemiluminescence emission intensity.

[0072] Example 1 Propylene was polymerized in the gas phase in the presence of a Ziegler-Natta catalyst to obtain a powdered polypropylene resin with an intrinsic viscosity of 3.0 dL / g. The polypropylene was then mixed with 100% by mass of the polymer, containing 0.01% by mass of synthetic hydrotalcite (trade name: DHT-4C, manufactured by Kyowa Chemical Industry Co., Ltd.) as a neutralizing agent, 0.2% by mass of pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (trade name: Irganox 1010, manufactured by BASF Japan Ltd.) as a phenolic antioxidant, and 0.2% by mass of tris(2,4-di-t-butylphenyl)phosphite (trade name: Irgafo) as a phosphorus antioxidant. 0.2% by mass of sS168 (BASF Japan Ltd.) and 0.05% by mass of a peroxide masterbatch (consisting of 8% by mass of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane (molecular weight: 290.44, number of peroxide bonds per molecule: 2) and 92% by mass of polypropylene) were blended and melt-kneaded at 230°C using a single-screw extruder with a screw diameter of 40 mm. The extruded strands were water-cooled and chopped into pellets using a pelletizer to obtain a polyolefin-based virgin resin.

[0073] The polyolefin virgin resin was heated and melted at a resin temperature of 250°C using a T-die film-forming machine equipped with an extruder with a screw diameter of 20 mm, and extruded onto a cooling roll at 20°C to obtain a film made of polyolefin virgin resin. The thickness of this film was 30 µm.

[0074] The obtained film was shredded and placed in a Laboplastomill (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and melt-kneaded for 5 minutes in a nitrogen atmosphere at a set temperature of 230°C and a screw rotation speed of 60 rpm to obtain a polyolefin-based recycled resin.

[0075] Example 2 A polyolefin virgin resin, a film, and a polyolefin recycled resin were obtained in the same manner as in Example 1, except that the amount of the peroxide masterbatch was set to 0.2% by mass.

[0076] Example 3 A polyolefin virgin resin, a film, and a polyolefin recycled resin were obtained in the same manner as in Example 1, except that the amount of the peroxide masterbatch was set to 0.8% by mass.

[0077] Example 4 A polyolefin virgin resin, a film, and a polyolefin recycled resin were obtained in the same manner as in Example 2, except that the amount of the phenolic antioxidant was 1% by mass and the amount of the phosphorus-based antioxidant was 1% by mass.

[0078] Example 5 A polyolefin virgin resin, a film, and a polyolefin recycled resin were obtained in the same manner as in Example 4, except that the amount of the peroxide masterbatch was set to 0.8% by mass.

[0079] Example 6 A polyolefin-based virgin resin, a film, and a polyolefin-based recycled resin were obtained in the same manner as in Example 1, except that the intrinsic viscosity of the polypropylene was set to 1.6 dl / g and the amount of the peroxide masterbatch was set to 0.15 mass %.

[0080] (Reference example 1) A polyolefin-based virgin resin, a film, and a polyolefin-based recycled resin were obtained in the same manner as in Example 1, except that the peroxide masterbatch was not used.

[0081] (Comparative Example 1) A polyolefin virgin resin, a film, and a polyolefin recycled resin were obtained in the same manner as in Example 1, except that the amount of the phenolic antioxidant was 0.04% by mass and the amount of the phosphorus-based antioxidant was 0.04% by mass.

[0082] (Comparative Example 2) A polyolefin virgin resin, a film, and a polyolefin recycled resin were obtained in the same manner as in Comparative Example 1, except that the amount of the peroxide masterbatch was set to 0.2% by mass.

[0083] (Comparative Example 3) A virgin polyolefin resin, a film, and a recycled polyolefin resin were obtained in the same manner as in Example 6, except that the amount of the peroxide masterbatch was set to 0.5% by mass.

[0084] [Evaluation of processing stability] The processing stability was evaluated by calculating the ratio of the melt flow rate of the recycled polyolefin resin to the melt flow rate of the virgin polyolefin resin (melt flow rate ratio). The calculation results of the melt flow rate ratio are shown in Table 1.

[0085] [Evaluation of oxidation-induced deterioration] Degradation due to oxidation was evaluated by calculating the ratio of the integrated chemiluminescence intensity of the recycled polyolefin resin to the integrated chemiluminescence intensity of the virgin polyolefin resin (integrated chemiluminescence intensity ratio). The calculation results of the integrated chemiluminescence intensity ratio are shown in Table 1.

[0086] [Table 1]

[0087] The results in Table 1 show that the polyolefin-based recycled resins of Examples 1 to 6, which satisfy all of the constituent requirements of the present invention, have relatively low melt flow rate ratios and chemiluminescence integrated luminescence intensity ratios compared to the polyolefin-based recycled resins of each comparative example, and therefore have relatively stable processability and are relatively less susceptible to deterioration due to oxidation.

Claims

1. Contains a polyolefin resin, a peroxide, and an antioxidant, a melt flow rate measured at 230°C under a load of 2.16 kg of 0.1 g / 10 min or more and 23 g / 10 min or less; The theoretical amount of active oxygen is 1.0 × 10 relative to 100% by mass of the polyolefin resin. －５ Mass% or more 1.8×10 －２ % by mass or less, The content of the antioxidant is 0.1% by mass or more and 4.0% by mass or less with respect to 100% by mass of the polyolefin-based resin. Recycled polyolefin resin.

2. the polyolefin resin is polypropylene, The content of the polypropylene is 50% by mass or more relative to 100% by mass of the polyolefin-based recycled resin. The recycled polyolefin resin according to claim 1.

3. The antioxidant is a phenol-based antioxidant and a phosphorus-based antioxidant. The recycled polyolefin resin according to claim 1.

4. A method for producing a polyolefin-based recycled resin according to any one of claims 1 to 3, comprising carrying out a kneading step of kneading the polyolefin-based resin, In the kneading step, the peroxide is further added. A method for producing recycled polyolefin resin.

5. The polyolefin-based recycled resin according to any one of claims 1 to 3 is used. Molded body.

6. It is a film, The molded article according to claim 5.

Images