Molded article containing recycled polyester resin

Abstract

To provide a molded article containing a recycled polyester resin, characterized by superior strength and reduced whitening.SOLUTION: The present invention provides a molded article that is derived from molding of a resin composition containing a recycled polyester resin, where ΔL is 9.5 or less, and the solution of the molded article has a haze of 1.50% or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a molded article containing a recycled polyester resin. [Background technology]

[0002] In recent years, there has been a demand for recycling resins from the viewpoints of resource reuse and environmental protection. However, polyester resins have a problem that their melt viscosity decreases and their strength deteriorates every time they are recycled. As a technique for solving such a problem, a technique of adding a chain extender (sometimes called a "viscosity modifier" or "melt viscosity improver: MVI") is known (for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2004 / 039887 [Patent Document 2] International Publication No. 2004 / 041934 [Patent Document 3] International Publication No. 2007 / 040041 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned conventional techniques are not sufficient from the viewpoint of preventing whitening of molded articles, and there is room for further improvement.

[0005] One embodiment of the present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a molded body containing a recycled polyester-based resin, which has excellent strength and reduced whitening. [Means for solving the problem]

[0006] The present inventors conducted extensive research to solve the above problems and have now completed the present invention.

[0007] That is, one embodiment of the present invention includes the following configuration. [1] A molded article obtained by molding a resin composition containing a recycled polyester resin, ΔL is 9.5 or less, The haze of the solution of the molded body is 1.50% or more. Here, the ΔL is a value obtained by carrying out the following steps (1) to (6) in order: (1) The resin composition is heated to 270°C using an extruder equipped with a T-die to form a film having a thickness of 200 µm; (2) The obtained film is punched into a dumbbell shape No. 2 according to JIS K 6251 to obtain a dumbbell; (3) The L value of the obtained dumbbell is measured using a colorimeter, and the obtained value is regarded as the L value before tension; (4) The dumbbell is stretched to 8.5 times its original size at 95°C and 1000 mm / min in a tensile tester in accordance with JIS K 7113; (5) The L value of the stretched dumbbell is measured using the colorimeter, and the obtained value is regarded as the L value after stretching; (6) subtract the L value before tension from the L value after tension, and the resulting difference is designated as ΔL; The haze of the solution of the molded body is a value measured by carrying out the following steps (7) to (8) in this order: (7) dissolving the molded body in hexafluoro-2-propanol to obtain a solution having a solid concentration of 0.05 g / mL; (8) Using a haze meter whose zero has been adjusted with the hexafluoro-2-propanol, the haze of the resulting solution of the molded bodies is measured. [2] The molded article according to [1], wherein the melt flow rate (MFR) of the resin composition is 3.7 g / 10 min to 30.0 g / 10 min. The MFR is a value determined by measurement in accordance with JIS K 7210-1 under conditions of drying at 130° C. for 8 hours, temperature of 270° C., and load of 2.16 kg. [3] The molded article according to [1] or [2], wherein the molded article has a total light transmittance (TT) of 80% or more. Here, the total light transmittance (TT) of the molded article is a value obtained by measurement using a haze meter. [4] The molded body according to any one of [1] to [3], wherein the recycled polyester-based resin includes at least one selected from the group consisting of recycled [polycarbonate / polyethylene terephthalate], recycled [polyethylene terephthalate / glycol-modified polyethylene terephthalate], and recycled [polyethylene terephthalate / copolymerized polyethylene terephthalate]. [5] The molded article according to any one of [1] to [4], wherein the molded article has a bottle shape. Effect of the Invention

[0008] According to one embodiment of the present invention, it is possible to provide a molded article containing a recycled polyester resin, which has excellent strength and reduced whitening. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to each configuration described below, and various modifications are possible within the scope of the claims. In addition, embodiments or examples obtained by combining the technical means disclosed in different embodiments or examples are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic documents and patent documents described in this specification are incorporated herein by reference. In addition, unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more (including A and greater than A) and B or less (including B and smaller than B)".

[0010] [1. Molded body] A molded article according to one embodiment of the present invention is a molded article obtained by molding a resin composition containing a recycled polyester resin, and has a ΔL of 9.5 or less and a haze of a solution of the molded article of 1.50% or more. Here, the ΔL is a value obtained by carrying out the following steps (1) to (6) in order; (1) the resin composition is heated to 270°C using an extruder equipped with a T-die to form a film having a thickness of 200 μm; (2) the obtained film is punched into a dumbbell-shaped No. 2 shape according to JIS K 6251 to obtain a dumbbell; (3) the L value of the obtained dumbbell is measured using a colorimeter, and the obtained value is defined as the L value before tension; (4) the dumbbell is stretched to 8.5 times its original size at 95°C and 1000 mm / min using a tensile tester in accordance with JIS K 7113; (5) the L value of the stretched dumbbell is measured using the colorimeter, and the obtained value is defined as the L value after tension; (6) the L value before tension is subtracted from the L value after tension, and the obtained difference is defined as ΔL; The haze of the solution of the molded body is a value measured by carrying out the following steps (7) to (8) in order: (7) dissolving the molded body in hexafluoro-2-propanol to obtain a solution with a solid concentration of 0.05 g / mL; (8) using a haze meter zero-adjusted with the hexafluoro-2-propanol, the haze of the obtained solution of the molded body is measured.

[0011] In this specification, the "molded body according to one embodiment of the present invention" may be referred to as the "molded body of the present invention". In this specification, the "resin composition containing recycled polyester resin" may be simply referred to as the "resin composition". The resin composition that is the raw material of the molded body of the present invention may also be referred to as the resin composition of one embodiment of the present invention. In this specification, the "resin composition according to one embodiment of the present invention" may be referred to as the "resin composition of the present invention".

[0012] The present molded article has the advantages of being excellent in strength and having reduced whitening.

[0013] The molded article contains recycled polyester resin. Therefore, one embodiment of the present invention can significantly reduce the amount of plastic waste generated and the amount of plastic used in the production. As a result, one embodiment of the present invention can contribute to the achievement of the Sustainable Development Goals (SDGs), such as Goal 12 "Ensure sustainable consumption and production patterns."

[0014] [Resin composition] The present molded article is obtained by molding a resin composition containing a recycled polyester resin. It can also be said that the present molded article contains a resin composition containing a recycled polyester resin.

[0015] (Recycled polyester resin) In this specification, the term "recycled polyester resin" refers to a polyester resin obtained by recycling the following (i) and / or (ii): (i) A polyester resin composition and / or a molded article that has once been manufactured into a product and then used and / or discarded; (ii) Waste polyester resin compositions and / or waste molded articles discharged during the production process of polyester resin compositions and / or molded articles.

[0016] On the other hand, in this specification, a polyester resin that has never been commercialized may be referred to as a "virgin polyester resin." In this specification, the term "recycled polyester resin" also includes a mixture obtained by mixing a "virgin polyester resin" with a recycled polyester resin.

[0017] In this specification, "X resin obtained by recycling" may also be referred to as "recycled [X resin]."

[0018] The method for recycling polyester resins is not particularly limited, but any known method can be used, such as chemical recycling, material recycling, and thermal recycling.

[0019] The polyester resin may be an aromatic polyester having a structure in which an aromatic dicarboxylic acid or its ester derivative component and a diol component such as an aliphatic diol or an alicyclic diol are linked by an ester reaction. The polyester resin may be obtained by polycondensing an aromatic dicarboxylic acid or its ester derivative component and a diol component such as an aliphatic diol or an alicyclic diol by a known method.

[0020] The aromatic dicarboxylic acid is not particularly limited, and examples thereof include phthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-diphenylethercarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 4,4'-diphenylisopropylidenedicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, bis(4,4-carboxyphenyl)methane, anthracenedicarboxylic acid (e.g., 2,5-anthracenedicarboxylic acid, 2,6-anthracenedicarboxylic acid, etc.), 4,4'-p-terphenylenedicarboxylic acid, and 2,5-pyridinedicarboxylic acid. The aromatic dicarboxylic acid may be used alone or in combination of two or more kinds.

[0021] The aliphatic diol is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, 2-methyl-1,3-propanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene glycol, bisphenol A ethylene oxide addition diol, polyethylene oxide glycol, and polypropylene oxide glycol. Examples of alicyclic diols include 1,4-cyclohexanedimethanol, 4,4-dicyclohexylhydroxymethane, and 4,4'-dicyclohexylhydroxypropane. As the diol component, only one type may be used, or two or more types may be used in combination.

[0022] The polyester resin may be a polymer formed by copolymerizing an aromatic dicarboxylic acid or its ester derivative component as a main component, an aliphatic diol, and another dicarboxylic acid or its ester derivative component or a diol. Examples of the other dicarboxylic acid include alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and 4,4'-dicyclohexyldicarboxylic acid.

[0023] The polyester resin may have a structural component derived from a tri- or higher functional monomer, such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, or pyromellitic acid.

[0024] Specific examples of recycled polyester resins are not particularly limited, but include, for example, recycled [polyethylene terephthalate], recycled [polypropylene terephthalate], recycled [polybutylene terephthalate], recycled [polyethylene-2,6-naphthalate], recycled [polybutylene naphthalate], recycled [poly 1,4-cyclohexylene dimethylene terephthalate], recycled [polyethylene-1,2-bis(phenoxy)ethane-4,4'-dicarboxylate], recycled [polyethylene isophthalate / terephthalate], recycled [polybutylene terephthalate / isophthalate], recycled [polybutylene terephthalate / decane dicarboxylate], recycled [polycyclohexane dimethylene terephthalate / isophthalate], recycled [polyester / polyether], recycled [glycol-modified polyethylene terephthalate], etc. Glycol-modified polyethylene terephthalate refers to a copolymer of terephthalic acid, ethylene glycol, and a glycol component other than ethylene glycol.

[0025] From the viewpoint of moldability and mechanical properties, the polyester-based resin preferably contains one or more types selected from the group consisting of recycled [polypropylene terephthalate], recycled [polybutylene terephthalate], recycled [polyethylene-2,6-naphthalate], recycled [polybutylene naphthalate], recycled [poly 1,4-cyclohexylene dimethylene terephthalate] and recycled [polyester / polyether], and may be composed of only one or more types selected from this group, or more preferably contains one or more types selected from the group consisting of recycled [polyethylene terephthalate] and recycled [polybutylene terephthalate], and may be composed of only one or more types selected from this group.

[0026] As the recycled polyester resin, a recycled [polymer alloy] obtained by recycling a polymer alloy obtained from a mixture of multiple polymers containing a polyester resin may be used. Examples of the recycled [polymer alloy] include recycled [polycarbonate / polyethylene terephthalate], recycled [polyethylene terephthalate / glycol-modified polyethylene terephthalate], and recycled [polyethylene terephthalate / copolymerized polyethylene terephthalate]. In other words, the recycled polyester resin may contain one or more selected from the group consisting of recycled [polycarbonate / polyethylene terephthalate], recycled [polyethylene terephthalate / glycol-modified polyethylene terephthalate], and recycled [polyethylene terephthalate / copolymerized polyethylene terephthalate], or may be composed of only one or more selected from the group. The copolymerized polyethylene terephthalate refers to a resin in which a component (third component) other than the components (two components) constituting polyethylene terephthalate is copolymerized.

[0027] (Whitening inhibitor) The molded article is preferably molded using a whitening inhibitor. In other words, the resin composition preferably contains a whitening inhibitor. By molding using the whitening inhibitor, (i) the melt viscosity of the resin composition can be improved, and the strength of the molded article made of the resin composition can be increased, and (ii) whitening of the molded article containing the recycled polyester resin can be suppressed.

[0028] The whitening suppressant is not particularly limited. For example, the whitening suppressant for polyester resin having the following composition is preferably used: (a) 10 parts by weight to 60 parts by weight of epoxy group-containing alkyl (meth)acrylate, and (b) 40 parts by weight to 90 parts by weight of non-epoxy group-containing alkyl (meth)acrylate, the monomer mixture (A) containing polymer (A) is polymerized, the monomer mixture (A) containing: (a) 10 parts by weight to 60 parts by weight of epoxy group-containing alkyl (meth)acrylate, and (b) 40 parts by weight to 90 parts by weight of non-epoxy group-containing alkyl (meth)acrylate.

[0029] (Polymer (A)) In this specification, "(a) epoxy group-containing monomer" may be referred to as "component (a)," and "(b) epoxy group-free monomer" may be referred to as "component (b)."

[0030] In this specification, the term "(a) epoxy group-containing monomer" refers to a monomer that contains an epoxy group.

[0031] The epoxy group has a good reactivity with the terminal functional group of the recycled polyester resin, and therefore, the whitening inhibitor preferably contains (a) an epoxy group-containing monomer.

[0032] The case where the resin composition contains a whitening inhibitor will be described. In this case, during the manufacturing process of the resin composition containing the recycled polyester resin and the whitening inhibitor (for example, during melt-kneading of the recycled polyester resin and the whitening inhibitor), the reactive functional group (for example, an epoxy group) in the polymer (A) contained in the whitening inhibitor can react with the terminal functional group (for example, a hydroxyl group or a carboxyl group) of the recycled polyester resin. This reaction can elongate the molecular chain of the recycled polyester resin; this mechanism improves the melt viscosity of the resin composition and improves the strength of the molded body. In addition, the whitening inhibitor contains the above-mentioned polymer (A), so that the dispersibility of the whitening inhibitor in the polyester resin composition can be improved. It is presumed that this suppresses the whitening of the molded body. It should be noted that the present invention is not limited to these mechanisms and presumptions.

[0033] The (a) epoxy group-containing monomer is not particularly limited. In one embodiment of the present invention, the epoxy group-containing monomer is preferably an epoxy group-containing alkyl (meth)acrylate. In the following, the epoxy group-containing alkyl (meth)acrylate will be mainly described as the (a) component.

[0034] Examples of the (a) component include, but are not limited to, glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, 3,4-epoxycyclohexyl (meth)acrylate, allyl glycidyl ether, β-methylglycidyl (meth)acrylate, etc. As the (a) component, only one type may be used, or two or more types may be used in combination.

[0035] From the viewpoint of polymerization productivity, the component (a) preferably contains (i) one or more selected from the group consisting of glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, 3,4-epoxycyclohexyl (meth)acrylate, and β-methylglycidyl (meth)acrylate, and may be composed of only one or more selected from this group, and more preferably contains (ii) one or more selected from the group consisting of glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, and 3,4-epoxycyclohexyl (meth)acrylate. , or may be composed of only one or more types selected from this group; (iii) it is more preferable that it contains one or more types selected from the group consisting of glycidyl acrylate, glycidyl methacrylate, and 4-hydroxybutyl acrylate glycidyl ether, and may be composed of only one or more types selected from this group; (iv) it is particularly preferable that it contains one or more types selected from the group consisting of glycidyl acrylate and glycidyl methacrylate, and may be composed of only one or more types selected from this group; and (v) it is most preferable that it contains glycidyl methacrylate, and may be composed of only glycidyl methacrylate.

[0036] The content of the (a) component in the monomer mixture (A) is not particularly limited, but is preferably 10% by weight to 60% by weight of 100% by weight of the monomer mixture (A). The upper limit may be 55%, 50%, 45%, or 40% by weight, and the lower limit may be 15%, 20%, 25%, or 30% by weight. If the content of the (a) component is within the above range, the effect of improving the melt viscosity of the polyester resin composition may be good. As a result, there is an advantage that the moldability and strength of the molded product are excellent. In this specification, "excellent moldability of the molded product" means that the thickness distribution of the molded product is more uniform.

[0037] In this specification, "(b) epoxy group-free monomer" refers to a monomer other than "(a) epoxy group-containing monomer", that is, a monomer that does not contain an epoxy group.

[0038] The component (b) is preferably an alkyl (meth)acrylate having no reactive functional group. Specific examples of the alkyl (meth)acrylate having no reactive functional group include alkyl (meth)acrylates having an alkyl group having 1 to 22 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate.

[0039] As the component (b), only one of the above-mentioned monomers may be used, or two or more of them may be used in combination.

[0040] The number of carbon atoms in the alkyl group in component (b) is not particularly limited, but from the viewpoint of polymerizability, it is preferably 22 or less. Furthermore, from the viewpoint of compatibility with recycled polyester resins, the number of carbon atoms in the alkyl group in component (b) is more preferably 12 or less, even more preferably 8 or less, and particularly preferably 1 to 4.

[0041] From the viewpoint of dispersibility of the whitening inhibitor, component (b) preferably contains one or more selected from the group consisting of epoxy group-free alkyl methacrylates, and may consist of only one or more selected from this group; (ii) more preferably contains one or more selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate, and may consist of only one or more selected from this group; (iii) even more preferably contains one or more selected from the group consisting of methyl methacrylate and butyl methacrylate, and may consist of only one or more selected from this group; and (iv) most preferably contains methyl methacrylate, and may consist of only methyl methacrylate.

[0042] The content of the (b) component in the monomer mixture (A) is not particularly limited, but is preferably 40% by weight to 90% by weight of 100% by weight of the monomer mixture (A). The upper limit may be 85% by weight, 80% by weight, 75% by weight, or 70% by weight, and the lower limit may be 45% by weight, 50% by weight, 55% by weight, or 60% by weight. If the content of the (b) component is within the above range, there is an advantage that the dispersibility of the whitening inhibitor in the polyester resin composition can be improved. As a result, there is also an advantage that the whitening of the obtained molded body is further suppressed.

[0043] The monomer mixture (A) preferably further contains (c) a vinyl monomer other than the components (a) and (b) that is copolymerizable with the components (a) and (b). In this specification, "(c) a vinyl monomer other than the components (a) and (b) that is copolymerizable with the components (a) and (b)" may be referred to as "component (c)".

[0044] Examples of the component (c) include, but are not limited to, vinyl cyanide compounds, aromatic vinyl compounds, (meth)acrylic acid, and the like.

[0045] Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.

[0046] The aromatic vinyl compound is not particularly limited, but examples thereof include styrene, vinyltoluene, α-methylstyrene, 4-methylstyrene, 3-methylstyrene, 4-methoxystyrene, 4-ethylstyrene, 4-ethoxystyrene, 3,4-dimethylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chloro-3-methylstyrene, 3-(tert-butyl)styrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, and 1-vinylnaphthalene.

[0047] As the component (c), only one of the above-mentioned monomers may be used, or two or more of them may be used in combination.

[0048] From the viewpoint of polymerization productivity, the component (c) preferably contains (i) one or more selected from the group consisting of 4-methylstyrene, 3-methylstyrene, α-methylstyrene, and styrene, and may be composed of only one or more selected from this group, (ii) more preferably contains one or more selected from the group consisting of 4-methylstyrene, α-methylstyrene, and styrene, and may be composed of only one or more selected from this group, (iii) further preferably contains one or more selected from the group consisting of α-methylstyrene and styrene, and may be composed of only one or more selected from this group, and (iv) most preferably contains styrene, and may be composed of only styrene.

[0049] On the other hand, since it is possible to provide a molded article with further reduced whitening, it is preferable that the content of the aromatic vinyl compound (particularly styrene) as component (c) in the monomer mixture (A) is as low as possible. In 100% by weight of the monomer mixture (A), the content of the aromatic vinyl compound is preferably 10% by weight or less, more preferably 5% by weight or less, even more preferably 3% by weight or less, and particularly preferably 1% by weight or less. In 100% by weight of the monomer mixture (A), the content of the aromatic vinyl compound is more preferably 0% by weight, that is, it is most preferable that the monomer mixture (A) does not contain an aromatic vinyl compound. Since it is possible to provide a molded article with further reduced whitening, it is preferable that the content of styrene is 10% by weight or less, more preferably 5% by weight or less, even more preferably 3% by weight or less, and particularly preferably 1% by weight or less, in 100% by weight of the monomer mixture (A). It is more preferable that the styrene content is 0% by weight in 100% by weight of the monomer mixture (A), that is, it is most preferable that the monomer mixture (A) does not contain styrene.

[0050] The content of the (c) component in the monomer mixture (A) is not particularly limited, but is preferably 0 to 10% by weight, based on 100% by weight of the monomer mixture (A). The upper limit may be 8% or 5% by weight, and the lower limit may be 2% or 4% by weight. If the content of the (c) component is within the above range, there is an advantage that the productivity is improved.

[0051] From the viewpoint of the balance between the thermal stability and productivity of the whitening inhibitor and the improvement of the melt viscosity of the resin composition, the number average molecular weight of the polymer (A) is preferably in the range of 2,000 to 6,000. The lower limit of the number average molecular weight of the polymer (A) is more preferably 3,000 or more, and may be 4,000 or more. The upper limit of the number average molecular weight of the polymer (A) is more preferably 5,500 or less, more preferably 5,000 or less, even more preferably 4,500 or less, particularly preferably 4,000 or less, and may be 3,500 or less. The number average molecular weight of the polymer (A) can be adjusted by using a chain transfer agent during polymerization of the polymer (A). In other words, in order to obtain a polymer (A) having a number average molecular weight within the above-mentioned range, it is preferable to use a chain transfer agent during polymerization of the polymer (A). The number average molecular weight of the polymer (A) can be measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene. The method for measuring the number average molecular weight of the polymer (A) will be described in detail in the following examples.

[0052] The polymer (A) preferably has an average of 2 to 15 reactive functional groups per molecule of the polymer (A). The lower limit may be 3 or more. The upper limit may be any of 13 or less, 11 or less, and 9 or less. When the number of reactive functional groups in the polymer (A) is within the above range, gelation does not occur and the melt viscosity of the resin composition can be suitably improved without impairing the mechanical properties, heat resistance, rheological properties, etc. of the molded article.

[0053] The polymer (A) is preferably a non-rubber polymer. A non-rubber polymer refers to a polymer that does not have a crosslinked structure between molecular chains of the polymer. When the polymer (A) is a non-rubber polymer, the reaction between the reactive functional group (e.g., epoxy group) of the polymer (A) and the terminal functional group of the recycled polyester resin proceeds more efficiently, and the melt viscosity of the resin composition is easily improved.

[0054] (Method for producing polymer (A)) The polymerization method of the polymer (A) can be a known method, and is not particularly limited. For example, bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. can be adopted, and emulsion polymerization is preferred. When producing the polymer (A), it is preferable to carry out polymerization in the presence of a chain transfer agent in order to control the molecular weight. In other words, the monomer mixture (A) preferably contains a chain transfer agent.

[0055] Examples of the chain transfer agent include, but are not limited to, primary mercaptan chain transfer agents such as n-butyl mercaptan, n-octyl mercaptan, n-hexadecyl mercaptan, n-dodecyl mercaptan, and n-tetradecyl mercaptan; secondary mercaptan chain transfer agents such as sec-butyl mercaptan and sec-dodecyl mercaptan; tertiary mercaptan chain transfer agents such as t-dodecyl mercaptan; mercaptan compounds; thioglycolic acid esters such as 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris(thioglycolate), and pentaerythritol tetrakis(thioglycolate); thiophenol; tetraethyl thiuram disulfide; pentane phenyl ethane; acrolein; methacrolein; allyl alcohol; carbon tetrachloride; ethylene bromide; styrene oligomers such as α-methylstyrene dimer; and terpinolene. The chain transfer agent may be used alone or in combination of two or more. The amount of the chain transfer agent used may be appropriately determined depending on the desired number average molecular weight of the polymer (A).

[0056] The emulsifier (dispersant) that can be used in emulsion polymerization is not particularly limited, but includes anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, etc. Also, dispersants such as polyvinyl alcohol, alkyl-substituted cellulose, polyvinylpyrrolidone, polyacrylic acid derivatives, etc. may be used. The emulsifier (dispersant) may be used alone or in combination of two or more.

[0057] When the emulsion polymerization method is employed, a thermally decomposable initiator can be used as the radical polymerization initiator. Examples of the thermally decomposable initiator include known initiators such as 2,2'-azobisisobutyronitrile, hydrogen peroxide, potassium persulfate, and ammonium persulfate.

[0058] As the radical polymerization initiator, a redox type initiator can also be used. The redox type initiator is an initiator in which (a) a peroxide such as an organic peroxide or an inorganic peroxide is used in combination with (b) a reducing agent such as sodium formaldehyde sulfoxylate or glucose, if necessary, a transition metal salt such as iron (II) sulfate, if necessary, a chelating agent such as disodium ethylenediaminetetraacetate, if necessary, and a phosphorus-containing compound such as sodium pyrophosphate, if necessary. Examples of the organic peroxide include t-butyl peroxyisopropyl carbonate, paramenthane hydroperoxide, cumene hydroperoxide, dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, and t-hexyl peroxide. Examples of the inorganic peroxide include hydrogen peroxide, potassium persulfate, and ammonium persulfate.

[0059] When a redox type initiator is used, polymerization can be performed even at a low temperature where the peroxide does not substantially decompose thermally, and the polymerization temperature can be set in a wide range. Therefore, it is preferable to use a redox type initiator. Among the redox type initiators, redox type initiators using organic peroxides such as cumene hydroperoxide, dicumyl peroxide, paramenthane hydroperoxide, and t-butyl hydroperoxide as peroxides are preferable. The amount of the initiator used, and the amount of the reducing agent, transition metal salt, chelating agent, etc. used when a redox type initiator is used can be within a known range.

[0060] In the polymerization of the polymer (A), a known surfactant may also be used.

[0061] When the polymer (A) is produced by emulsion polymerization, a latex (e.g., aqueous latex) containing the polymer (A) can be obtained. The polymer (A) can be obtained by separating the polymer (A) from the latex containing the polymer (A). The obtained polymer (A) can be used as a whitening inhibitor. The method for separating the polymer (A) from the latex containing the polymer (A) is not particularly limited, but examples include salting out the polymer (A) using an acid and a metal salt, and precipitating the polymer (A) using an organic solvent. The polymer (A) separated from the latex containing the polymer (A) may be washed and further dried. The polymer (A) can be separated from the latex containing the polymer (A), washed, and further dried to obtain a powder (also referred to as "powder") of the polymer (A). The latex containing the polymer (A) can also be spray-dried to obtain a powder of the polymer (A). The powder of the polymer (A) thus obtained can be used as a whitening inhibitor.

[0062] (Polymer (B)) The whitening inhibitor may or may not contain a polymer (B) in addition to the polymer (A). The polymer component in the whitening inhibitor may be composed of only the polymer (A), may be composed of only the polymer (A) and the polymer (B), or may be composed of the polymer (A), the polymer (B) and a polymer other than these.

[0063] The case where the whitening inhibitor contains a polymer (A) and a polymer (B) (hereinafter also referred to as "case A") will be described. In case A, it is preferable to polymerize the polymer (B) in the presence of the polymer (A) after polymerizing the polymer (A). In case A, when the polymer (A) is obtained by, for example, emulsion polymerization, it is particularly preferable to produce (polymerize) the polymer (B) in a latex containing the polymer (A) after producing (polymerizing) the polymer (A). When the polymer (B) is produced (polymerized) in a latex containing the polymer (A), a composite consisting of the polymer (A) and the polymer (B) (or containing the polymer (A) and the polymer (B)) can be obtained. In the composite, the polymer (B) can cover a part of the polymer (A). Therefore, in the composite, the polymer (A) can be referred to as the core part and the polymer (B) as the shell part. The composite can have a core-shell structure having the polymer (A) as the core part and the polymer (B) as the shell part. In other words, when the polymer (B) is produced (polymerized) in a latex containing the polymer (A), a composite of the polymer (A) and the polymer (B) can be obtained, in which the polymer (A) forms the core and the polymer (B) forms the shell, that is, a composite having a core-shell structure. In the composite, the polymer (B) may cover the entire polymer (A) or may be impregnated into the particulate polymer (A).

[0064] When the whitening inhibitor contains a polymer (A) and a polymer (B) and the composite composed of the polymer (A) and the polymer (B) has a core-shell structure in which the polymer (A) forms the core and the polymer (B) forms the shell, there is an advantage in that productivity is improved.

[0065] The polymer (B) is not particularly limited. The composition of the structural unit of the polymer (B) may be the same as or different from the composition of the structural unit of the polymer (A). In other words, the composition of the monomer mixture (B) may be the same as or different from the composition of the monomer mixture (A).

[0066] The polymer (B) is preferably a polymer obtained by polymerizing a monomer mixture (B) containing (a) 10% by weight to 60% by weight of an epoxy group-containing monomer and (b) 40% by weight to 90% by weight of an epoxy group-free monomer. The polymer (B) preferably further contains (c) 0% by weight to 10% by weight of a vinyl monomer other than the components (a) and (b) that is copolymerizable with the components (a) and (b).

[0067] The number average molecular weight of the polymer (B) is preferably different from that of the polymer (A). The number average molecular weight of the polymer (B) is more preferably larger than that of the polymer (A). This configuration increases the softening point of the polymer (composite) and can reduce the occurrence of problems such as sticking. As a result, there is an advantage in that productivity is improved.

[0068] The polymer (B) is preferably a non-rubber polymer. This configuration has the advantage that the reaction between the reactive functional group of the polymer (B) and the terminal functional group of the recycled polyester resin proceeds more efficiently, and the melt viscosity of the resin composition is easily improved. In case A, (i) it is preferable that the polymer (A) is a non-rubber polymer or the polymer (B) is a non-rubber polymer, and it is more preferable that both the polymer (A) and the polymer (B) are non-rubber polymers (for example, the entire complex is a non-rubber polymer).

[0069] The case where the whitening inhibitor contains a polymer (A) and a polymer (B), and the composite made of the polymer (A) and the polymer (B) has a core-shell structure in which the polymer (A) forms a core portion and the polymer (B) forms a shell (hereinafter also referred to as "case B") will be described. In cases A and B, the ratio of the weight of the polymer (A) to the weight of the polymer (B) in the composite (weight of the polymer (A) / weight of the polymer (B)) is not particularly limited, but is preferably 20 / 80 to 80 / 20, more preferably 30 / 70 to 70 / 30, even more preferably 35 / 65 to 65 / 35, and particularly preferably 40 / 60 to 60 / 40. If the ratio of the weight of the polymer (A) to the weight of the polymer (B) in the composite is within the above range, there is an advantage that the productivity is improved.

[0070] In case B, the number average molecular weight of the polymer (A) is not particularly limited, but is preferably 2,000 to 5,000, more preferably 2,000 to 4,000, even more preferably 2,500 to 4,000, and particularly preferably 2,500 to 3,500. This configuration has the advantage of improving the balance between improving the melt viscosity and suppressing whitening. In cases A and B, the number average molecular weight of the polymer (B) is not particularly limited, but is preferably 3,000 to 6,000, more preferably 3,000 to 5,000, even more preferably 3,500 to 5,000, and particularly preferably 3,500 to 4,500. This configuration has the advantage of improving productivity.

[0071] The polymer (B) preferably has 2 to 15 reactive functional groups on average per molecule of the polymer (B). The lower limit may be 3 or more. The upper limit may be any of 13 or less, 11 or less, and 9 or less. When the number of reactive functional groups in the polymer (B) is within the above range, gelation does not occur and the melt viscosity of the resin composition can be suitably improved without impairing the mechanical properties, heat resistance, rheological properties, etc. of the molded article.

[0072] (Method for producing polymer (B)) The polymerization method of the polymer (B) can be a known method, and is not particularly limited. For example, bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. can be adopted, and emulsion polymerization is preferred. When producing the polymer (B), it is preferable to carry out polymerization in the presence of a chain transfer agent in order to control the molecular weight. In other words, the monomer mixture (B) preferably contains a chain transfer agent.

[0073] Regarding the polymer (B), the description in the section on [polymer (A)] may be appropriately applied except for the matters mentioned above. For example, regarding the types and contents of the components (a), (b) and (c) contained in the monomer mixture (B), the preferred embodiments for the polymer (A) (monomer mixture (A)) are also preferred for the polymer (B) (monomer mixture (B)).

[0074] The whitening inhibitor preferably has a smaller content of polymers having a number average molecular weight of 1000 or less. The whitening inhibitor has an advantage that the smaller the content of polymers having a number average molecular weight of 1000 or less in the whitening inhibitor, the more suitable it is for use in food applications.

[0075] The content of the polymer having a number average molecular weight of 1000 or less in the present whitening inhibitor is not particularly limited, but is preferably 4.00% by weight or less, more preferably 3.00% by weight or less, even more preferably 2.00% by weight or less, and particularly preferably 1.00% by weight or less, based on 100% by weight of the whitening inhibitor. This configuration has the advantage of being suitable for use in food products. The lower limit of the content of the polymer having a number average molecular weight of 1000 or less in the present whitening inhibitor is 0.00% by weight, that is, the present whitening inhibitor does not need to contain a polymer having a number average molecular weight of 1000 or less.

[0076] The whitening inhibitor preferably contains a smaller amount of polymer (A) having a number average molecular weight of 1000 or less. The amount of polymer (A) having a number average molecular weight of 1000 or less in the whitening inhibitor is not particularly limited, but is preferably 4.00% by weight or less, more preferably 3.00% by weight or less, even more preferably 2.00% by weight or less, and particularly preferably 1.00% by weight or less, based on 100% by weight of the whitening inhibitor. This configuration has the advantage of being suitable for use in food products. The lower limit of the amount of polymer (A) having a number average molecular weight of 1000 or less in the whitening inhibitor is 0.00% by weight, that is, the whitening inhibitor does not need to contain polymer (A) having a number average molecular weight of 1000 or less.

[0077] In case A, the content of the polymer (B) having a number average molecular weight of 1000 or less in the whitening inhibitor is preferably as small as possible. In case A, the content of the polymer (B) having a number average molecular weight of 1000 or less in the whitening inhibitor is not particularly limited, but is preferably 4.00% by weight or less, more preferably 3.00% by weight or less, even more preferably 2.00% by weight or less, and particularly preferably 1.00% by weight or less in 100% by weight of the whitening inhibitor. This configuration has the advantage of being suitable for use in food products. In case A, the lower limit of the content of the polymer (B) having a number average molecular weight of 1000 or less in the whitening inhibitor is 0.00% by weight, that is, the whitening inhibitor does not need to contain the polymer (B) having a number average molecular weight of 1000 or less.

[0078] The resin composition may or may not further contain a resin other than the recycled polyester resin. The resin other than the recycled polyester resin is not particularly limited, but examples thereof include virgin polyester resin, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, polytetrafluoroethylene, ABS resin, AS resin, acrylic resin, polyacetal, polycarbonate, modified polyphenylene ether, polyamide, and cyclic polyolefin.

[0079] The content of the resin other than the recycled polyester resin in the present resin composition is not particularly limited, but may be, for example, 0 to 60 parts by weight relative to 100 parts by weight of the recycled polyester resin. The upper limit may be 50 parts by weight or less, 40 parts by weight or less, 30 parts by weight or less, 20 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less.

[0080] (Other additives) The molded article may be molded using other additives. In other words, the resin composition may contain other additives. The other additives are not particularly limited, but may include, for example, a flame retardant, a flame retardant assistant, an anti-dripping agent, a reinforcing agent, a filler, an antioxidant, a pigment, a dye, a conductive agent, a hydrolysis inhibitor, a thickener, a plasticizer, a lubricant, an ultraviolet absorber, an antistatic agent, a flow improver, a release agent, a compatibilizer, and a heat stabilizer.

[0081] <Method of producing resin composition> The method for producing the resin composition is not particularly limited, and a general method for producing a resin composition can be applied. For example, the raw materials (e.g., recycled polyester resin and whitening inhibitor) are mixed using a Henschel mixer or a tumbler mixer, and then the resulting mixture is melt-kneaded to obtain a resin composition. For the melt-kneading, a kneading machine such as a single-screw or twin-screw extruder, a Banbury mixer, a pressure kneader, or a mixing roll can be used. By such melt-kneading, pellets made of the resin composition can be produced.

[0082] <Physical properties of resin composition> The higher the melt viscosity (IV value) of the resin composition, the more excellent the strength of the molded article that the resin composition can provide. In other words, the resin composition preferably has a high melt viscosity (IV value). The method for measuring the melt viscosity (IV value) of the resin composition will be described in detail in the Examples below.

[0083] The smaller the MFR of a resin composition, the more excellent the strength of a molded article that can be provided by the resin composition. In other words, it is preferable that the resin composition has a small MFR.

[0084] The melt flow rate (MFR) of the resin composition is preferably 3.7g / 10min to 30.0g / 10min, more preferably 3.7g / 10min to 29.5g / 10min, more preferably 3.7g / 10min to 29.0g / 10min, more preferably 3.7g / 10min to 28.5g / 10min, even more preferably 3.7g / 10min to 28.0g / 10min, and particularly preferably 3.7g / 10min to 27.5g / 10min. When the melt flow rate (MFR) of the resin composition is within the above-mentioned range, the molded article has an advantage of excellent strength. The method for measuring the MFR of the resin composition will be described in detail in the following examples.

[0085] A technique called solid-phase polymerization (SSP) is known as a method for improving the melt viscosity (IV value) of recycled polyester resin. Molded bodies obtained by molding a resin composition obtained by solid-phase polymerization using recycled polyester resin as a raw material have the advantage that they do not whiten at all, or even if they whiten, the degree of whitening is very small. However, solid-phase polymerization requires a huge amount of energy because it is carried out for a long time under vacuum and high temperature. The haze of a solution obtained by dissolving a molded body obtained from a resin composition obtained by solid-phase polymerization using recycled polyester resin as a raw material is, for example, about 1.0%. On the other hand, the haze of a solution obtained by dissolving a molded body obtained from this resin composition is, for example, 1.50% or more. In other words, when the haze of a solution obtained by dissolving a molded body is 1.50% or more, the molded body can be considered not to be a molded body obtained from a resin composition obtained by solid-phase polymerization. In one embodiment of the present invention, the haze of a solution obtained by dissolving a molded body may be 2.00% or more, 2.50% or more, or 3.00% or more.

[0086] [Method of manufacturing molded body] The method for producing the molded body, in other words, the molding method of the resin composition, is not particularly limited. The method for producing the molded body (the molding method of the resin composition) can be, for example, injection molding, extrusion molding, blow molding, calendar molding, inflation molding, rotational molding, press molding, etc. Among these, the blow molding method is preferred. In other words, the molded body according to one embodiment of the present invention is preferably a molded body obtained by blow molding the present resin composition.

[0087] In this specification, the blow molding method may be a molding method in which only blow molding is performed using a resin composition, or may be a molding method performed in combination with other molding methods (e.g., injection molding, extrusion molding, calendar molding, etc.). As a molding method performed in combination with other molding methods, a two-step blow molding method is preferred. The two-step blow molding method is a molding method in which a resin composition is injection molded in a first step to obtain an injection molded article, and then the injection molded article is blow molded in a second step.

[0088] [Physical properties of molded body] In one embodiment of the present invention, ΔL measured by the above-mentioned method is 9.5 or less. ΔL is measured using a film obtained by molding a resin composition, which is a raw material of the molded body, into a film. The film can also be said to be a molded body of the resin composition. Specifically, a tensile test is performed on the film (molded body), and the difference in L value before and after the tensile test is taken as ΔL. It is intended that the smaller ΔL is, the more the resin composition can provide a molded body with reduced whitening. For example, in the blow molding of a resin composition or an injection molded body, the resin composition or the injection molded body is molded while being stretched. It can be said that the stretching of the film (molded body) in the tensile test imitates the stretching during the blow molding of the resin composition or the injection molded body. Therefore, it can be said that the smaller the ΔL of the film (molded body), the more the whitening of the blow molded body (for example, a bottle-shaped molded body) obtained by blow molding is reduced. In other words, in one embodiment of the present invention, ΔL being 9.5 or less indicates that the molded body according to one embodiment of the present invention is a molded body with reduced whitening. The method for measuring ΔL will be described in detail in the examples below.

[0089] In one embodiment of the present invention, ΔL is 9.5 or less, preferably 9.0 or less, more preferably 8.0 or less, more preferably 7.0 or less, even more preferably 6.0 or less, and particularly preferably 5.0 or less. The lower limit is not particularly limited, and is most preferably 0, but may be 1.0, 1.5, or 2.0. ΔL being in the above range means that whitening of the molded body is suppressed.

[0090] The haze of the molded product is preferably 7.5 or less, more preferably 6.5 or less, more preferably 5.5 or less, more preferably 5.0 or less, even more preferably 4.5 or less, and particularly preferably 4.0 or less. The lower limit of the haze of the molded product is not particularly limited, and is, for example, 1.0. The haze of the molded product in the above range means that the transparency of the molded product is high. The method for measuring the haze of the molded product will be described in detail in the following examples.

[0091] The total light transmittance (TT) of the present molded product is preferably 80.0% or more, more preferably 80.5% or more, more preferably 81.0% or more, more preferably 81.5% or more, even more preferably 82.0% or more, and particularly preferably 82.5% or more. The upper limit of the total light transmittance (TT) of the molded product is not particularly limited, and is, for example, 100%. The total light transmittance (TT) of the molded product in the above range means that the molded product has high transparency. The method for measuring the total light transmittance (TT) of the molded product will be described in detail in the following examples.

[0092] The buckling strength of the molded article is preferably 200, more preferably 250, even more preferably 300, and particularly preferably 350. If the buckling strength of the molded article is within the above range, there is an advantage that the range of applications in which the molded article can be used is expanded. The method for measuring the buckling strength of the molded article will be described in detail in the Examples below.

[0093] The shape of the present molded product is not particularly limited. By using the resin composition and the various molding methods described above, molded products of various shapes can be obtained. Examples of the shape of the present molded product include a bottle shape, a sheet shape, a film shape, and a rod shape. Among these, the present molded product is preferably a bottle shape, and is particularly preferably a blow molded product (molded product) obtained by a blow molding method.

[0094] [2.Applications] The present molded article can be used in a variety of applications, including, but not limited to, automotive applications such as cylinder head covers, engine covers, intake manifolds, radiator tanks, oil pans, accelerator pedals, canisters, fuel tubes, air brake tubes, exhaust gas tubes, hydrogen injectors, ducts, industrial fasteners, and door mirror stays; electrical and electronic applications such as coil bobbins, connectors, gears, sockets, switches, electric blanket coated wires, optical fiber cable coating materials, power tools, and electric wire ties; mechanical applications such as hydraulic and pneumatic connectors and tubes, bearings, covers and housings, bearings, pressure resistant hoses, and cable ties; building material applications such as curtain rail parts, aluminum sash corners, door rollers, handrails, curtain rollers, and door handles; sports and leisure applications such as sports shoe soles, ski and snowboard equipment, reels, and diving snorkels; packaging materials and container applications such as shrink wrapping films, food packaging films, alcoholic beverage bottles, beverage bottles, and pesticide bottles; and medical applications such as toothbrushes, chair legs and armrests, and sutures. EXAMPLES

[0095] The present invention will be described in more detail with reference to the following examples and comparative examples. However, the present invention is not limited to these examples. Examples obtained by appropriately combining the technical means disclosed in each example are also included in the scope of the present invention.

[0096] [Measurement and evaluation methods] 1.Particle size of polymer or composite The particle size of the polymer or composite was measured using a Microtrac UPA (manufactured by Nikkiso Co., Ltd.) and was obtained by calculating the volume average particle size.

[0097] 2. Polymerization conversion rate The polymerization conversion rate was defined as the ratio (%) of the actual solid content to the solid content at the ideal conversion rate.

[0098] 3.Number average molecular weight The number average molecular weights of the polymer (A) and the polymer (B) were calculated by GPC measurement. The GPC device used was a device manufactured by Tosoh Corporation. The analysis conditions were as follows. Column 1 (low molecular weight column) 1st column: TSKgel SuperH5000 Second column: TSKgel SuperH4000 3rd column: TSKgel SuperH3000 4th column: TSKgel SuperH2000 Column 2 (polymer column) 1st column: TSKgel SuperHZM-H Second column: TSKgel SuperHZM-H Injection method: Syringe measurement Loop volume: 100μL Preliminary aspirate volume: 150μL Air volume: 3.5μL Automatic cleaning volume: 1.0mL Syringe Speed Sampling speed: 10μL / s Washing speed: 100μL / s Measuring speed: 5μL / s Sample flow rate: 0.350mL / min Reference flow rate ratio: 1x Flow control: Disabled Flow rate increase rate: 0.35mL / min Flow rate reduction rate: 0.35mL / min Pressure Limit Column 1 Sample pressure limit: 12.0MPa Sample pressure lower limit: 0.2MPa Reference pressure upper limit: 25.0MPa Reference pressure lower limit: 0.2MPa Column 2 Sample pressure limit: 25.0MPa Sample pressure lower limit: 0.2MPa Reference pressure upper limit: 12.0MPa Reference pressure lower limit: 0.2MPa flow rate Column 1 Sample flow rate: 0.600mL / min Reference flow ratio: 1 / 2 Column 2 Sample flow rate: 0.350mL / min Reference flow rate ratio: 1x Flow control: Disabled Flow rate increase rate: 0.35mL / min / min Flow rate reduction rate: 0.35mL / min / min Pressure Limit Column 1 Sample pressure limit: 12.0MPa Sample pressure lower limit: 0.2MPa Reference pressure upper limit: 25.0MPa Reference pressure lower limit: 0.2MPa Peak detection conditions RI Detection sensitivity (front side): 3.000mV / min Detection sensitivity (rear): 3.000mV / min Base judgment value: 1.000mV / min Exclusion area: 10.000mVs Rejection height: 0.000mV Rejection half-width: 0.000s UV / EXT Detection sensitivity (front side): 3.000mV / min Detection sensitivity (rear): 3.000mV / min Base judgment value: 1.000mV / min Exclusion area: 10.000mVs Rejection height: 0.000mV Rejection half-width: 0.000s Polystyrene was used as a standard substance. That is, polystyrene with a known number average molecular weight was used, and GPC was performed under the above-mentioned conditions to obtain a calibration curve. Then, GPC was performed under the above-mentioned conditions for the samples (polymer (A) and polymer (B)), and the number average molecular weight of each sample was calculated from the calibration curve.

[0099] 4. Melt Viscosity of Resin Composition (IV Value) The IV value of the resin composition was measured in accordance with JIS K 7367-5.

[0100] 5. Melt flow rate (MFR) of resin composition The melt flow rate (MFR) of the resin composition was measured in accordance with JIS K 7210-1 under the conditions of drying at 130° C. for 8 hours, a temperature of 270° C., and a load of 2.16 kg.

[0101] 6. ΔL of film (molded product) The ΔL of the resin composition of each of the Examples, Comparative Examples, and Reference Examples was measured by the following method: (1) Pellets of the resin composition were heated to 270° C. using an extruder equipped with a T-die (LABO PLASTOMILL, manufactured by Toyo Seiki Seisaku-sho) to form a film having a thickness of 200 μm; (2) The obtained film was punched into a dumbbell-shaped No. 2 shape according to JIS K 6251 to obtain a dumbbell; (3) The L value of the obtained dumbbell was measured using a colorimeter (Color Meter ZE6000, manufactured by Nippon Denshoku Kogyo Co., Ltd.), and the obtained value was regarded as the L value before tension; (4) The dumbbell was punched into a dumbbell-shaped No. 2 shape according to JIS K 6251 to obtain a dumbbell; In accordance with 7113, the film was stretched to 8.5 times its original size at 95°C and 1000 mm / min using a tensile tester (Shimadzu, AG-2000E); (5) The L value of the stretched dumbbell was measured using the colorimeter, and the obtained value was defined as the L value after stretching; (6) The L value before stretching was subtracted from the L value after stretching, and the obtained difference was defined as the ΔL of the film (molded product).

[0102] 7. Haze of the solution obtained by dissolving the molded body (1) The molded body was dissolved in hexafluoro-2-propanol (HFIP) to obtain a solution with a solid concentration of 0.05 g / mL; (2) The haze of the obtained solution was measured using a haze meter (Nippon Denshoku Industries Co., Ltd., Haze Meter NDH4000) zero-adjusted with HFIP.

[0103] 8. L value of molded product The L value of the molded product was measured using a color difference meter (Color Meter ZE6000, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0104] 9. Haze of Molded Product The haze of the molded product was measured using a haze meter (NDH4000, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0105] 10. Total light transmittance (TT) of molded body The total light transmittance (TT) of the molded article was measured using a haze meter (NDH4000, manufactured by Nippon Denshoku Industries Co., Ltd.).

[0106] 11. Bending strength The compact was used as a sample and measured using a compression tester (manufactured by AND Co., Ltd., MCT-1150) at a lowering speed of 50 mm / min.

[0107] 12. Bottle (molded product) wall thickness The wall thickness of the bottle (molded product) at each distance vertically upward from the bottom of the bottle (molded product) was measured using a magnetic thickness gauge (OLYMPUS, MAGNA MIKE).

[0108] [Production of whitening inhibitor] (Production Example 1) (Production of Polymer (A)) 180 parts by weight of purified water, 1.5 parts by weight of sodium formaldehyde sulfoxylate, 0.0075 parts by weight of EDTA, 0.3 parts by weight of ferrous sulfate heptahydrate, and 0.1 parts by weight of sodium polyoxyethylene lauryl ether phosphate were added to a reactor. The temperature in the reactor was increased to 75° C. while stirring the mixture in the reactor, and nitrogen was used to bubble the mixture for 30 minutes.

[0109] Then, a monomer mixture (A) consisting of 35 parts by weight of methyl methacrylate (MMA) as the component (b), 15 parts by weight of glycidyl methacrylate (GMA) as the component (a), and 2 parts by weight of n-octyl mercaptan as a chain transfer agent was added to the reactor over 150 minutes. In addition, while the monomer mixture (A) was being added (150 minutes), 0.1 parts by weight of t-butyl hydroperoxide as a polymerization initiator was added to the reactor over 150 minutes. In addition, 80 minutes after the addition of the monomer mixture (A), 0.2 parts by weight of sodium polyoxyethylene lauryl ether phosphate as an anionic surfactant was added to the reactor all at once. Then, the reaction was continued until the polymerization conversion rate reached 90%, and the reaction was continued for another 30 minutes after the polymerization conversion rate reached 90%. By this operation, a polymer (A) was obtained.

[0110] (Production of Polymer (B) (Production of Composite Having Core-Shell Structure)) Next, a monomer mixture (B) consisting of 35 parts by weight of MMA, 15 parts by weight of GMA, and 1.5 parts by weight of n-octyl mercaptan was added to the reactor containing the polymer (A). During the addition of the monomer mixture (B), 0.1 parts by weight of t-butyl hydroperoxide, which is a polymerization initiator, was added to the reactor. In addition, 0.2 parts by weight of sodium polyoxyethylene lauryl ether phosphate, which is an anionic surfactant, was added to the reactor from time to time during the addition of the monomer mixture (B). Thereafter, the reaction was continued until the polymerization conversion rate reached 98%, and from the point at which the polymerization conversion rate reached 98%, the reaction was continued for another 30 minutes. By this operation, a polymer (B) was obtained.

[0111] Finally, a latex containing a composite of polymer (A) and polymer (B) having a particle size of 1100 .ANG. was obtained. The final polymerization conversion rate was 98%.

[0112] In the composite obtained by the above-mentioned production method, the polymer (A) is considered to form the core portion, and the polymer (B) is considered to form the shell portion, i.e., the composite is considered to have a core-shell structure.

[0113] The obtained latex contained two kinds of number average molecular weights (Mn), the number average molecular weight of polymer (A) (core component) was 3,000, and the number average molecular weight of polymer (B) (shell component) was 4,000. The average number of epoxy groups in polymer (A) (core component) was 5, the average number of epoxy groups in polymer (B) (shell component) was 6, and the average number of epoxy groups per polymer molecule was 5.5.

[0114] In order to recover the composite particles as a powder from the latex, the obtained latex was quickly added to a 5% calcium chloride aqueous solution while stirring the 5% calcium chloride aqueous solution. The temperature of the mixture was maintained at 70°C by steam. The temperature of the mixture was then increased to 85°C to dehydrate the aggregates of the composite particles. The obtained aggregates were dried to obtain a composite powder. The powder was then sieved through an 18-mesh screen, and the powder that passed through the 18-mesh screen was obtained as a whitening inhibitor.

[0115] (Production Example 2) In (Production Example 1), (i) 35 parts by weight of MMA in the monomer mixture (A) was changed to 70 parts by weight of styrene (St), and 2 parts by weight of n-octyl mercaptan was changed to 1 part by weight, and (ii) 40 parts by weight of MMA in the monomer mixture (B) was changed to 20 parts by weight of St, 10 parts by weight of GMA was changed to 1 part by weight, and the amount of n-octyl mercaptan used was changed to 0 parts by weight (i.e., not used). Except for this, the same operation as in (Production Example 1) was carried out to obtain a latex containing a complex. The complex in the obtained latex had a number average molecular weight of 9,900 for the polymer (A) and a number average molecular weight of 120,000 for the polymer (B), an average number of epoxy groups per molecule of the polymer (A) was 9, and an average number of epoxy groups per molecule of the polymer (B) was unknown. Thereafter, a powder of the complex was obtained from the latex in the same manner as in (Production Example 1) and used as a whitening inhibitor.

[0116] For the whitening inhibitors of Production Examples 1 and 2, the parts by weight of each of the polymers (A) and (B), the number average molecular weight, the number of reactive functional groups per molecule, and the amount (wt%) of component (a) in 100 wt% of the polymer or composite are shown in Table 1.

[0117] [Table 1]

[0118] [Molded body] (raw materials) -Polyester resin: Recycled polyester resin (rPET FG Resins).

[0119] Whitening inhibitor: The whitening inhibitors of Production Examples 1 and 2 and Comparative Example 1 were melt-kneaded at 270°C using a single-screw extruder (LABO PLASTOMILL, Brabender, 19 mm, L / D=20, manufactured by Toyo Seiki Seisakusho), and the molten kneaded product extruded from a die was cut. By this operation, pellets of the whitening inhibitor were obtained. The obtained pellets of the whitening inhibitor were used in the production of a molded body.

[0120] (Examples 1 and 2, Comparative Example 1) (Production of resin composition) For each of the Examples and Comparative Examples, the polyester resin and the whitening inhibitor shown in Table 2 were fed to a twin-screw extruder (Leistritz, 35 mm, L / D=17) in the amounts shown in Table 2. The mixture was melt-kneaded at 270°C in the extruder, and the molten mixture extruded from the die was cut. By this operation, pellets of the resin composition were obtained.

[0121] (Reference example 1) The resin composition of Reference Example 1 was obtained by charging recycled polyester resin pellets into a batch-type SSP reactor and carrying out solid-phase polymerization at 230°C.

[0122] The melt viscosity (IV value) and MFR of the pellets of the resin compositions obtained in each of the Examples, Comparative Examples, and Reference Examples, or the pellets of the Reference Examples, were measured and evaluated by the above-mentioned method. Furthermore, the ΔL of the films (molded articles) of the resin compositions obtained in each of the Examples, Comparative Examples, and Reference Examples was measured by the above-mentioned method. The results are shown in Table 2.

[0123] [Table 2]

[0124] (Manufacture of bottles (molded bodies)) The pellets of the resin compositions obtained in each of the Examples, Comparative Examples, and Reference Examples were injection molded at a molding temperature of 280°C using an injection molding machine (Nissei Plastics, FNX-140, screw Φ45) to obtain a preform molded body. The obtained preform molded body was blow molded at a surface temperature of about 100°C using a blow molding machine (Frontier, FXT-1R) to obtain a bottle-shaped molded body with a volume of 500 ml.

[0125] The bottles (molded bodies) obtained in each of the Examples, Comparative Examples, and Reference Examples were measured for L value, haze, total light transmittance (TT), wall thickness (distance from the bottom), and buckling strength by the methods described above. The results are shown in Table 3. In addition, for the bottles (molded bodies) obtained in each of the Examples and Comparative Examples, the L value of Reference Example 2, which does not contain a whitening inhibitor, was subtracted from the L value of each of the Examples and Comparative Examples, and the obtained difference (value) was taken as ΔL of each of the Examples and Comparative Examples, and is shown in Table 3. In addition, the haze of the solution was measured for the bottles (molded bodies) obtained in each of the Examples and Comparative Examples.

[0126] [Table 3] [Industrial Applicability]

[0127] According to one embodiment of the present invention, it is possible to provide a molded article containing a recycled polyester resin, which has excellent strength and reduced whitening. Therefore, the molded article according to one embodiment of the present invention can be suitably used in the following fields: automotive applications such as cylinder head covers, engine covers, intake manifolds, radiator tanks, oil pans, accelerator pedals, canisters, fuel tubes, air brake tubes, exhaust gas tubes, hydrogen injectors, ducts, industrial fasteners, and door mirror stays; electrical and electronic applications such as coil bobbins, connectors, gears, sockets, switches, electric blanket coated wires, optical fiber cable coating materials, power tools, and electric wire ties; mechanical applications such as hydraulic and pneumatic connectors and tubes, bearings, covers and housings, bearings, pressure resistant hoses, and cable ties; building material applications such as curtain rail parts, aluminum sash corners, door rollers, handrails, curtain rollers, and door handles; sports and leisure applications such as sports shoe soles, ski and snowboard equipment, reels, and diving snorkels; packaging material and container applications such as shrink packaging films, food packaging films, alcoholic beverage bottles, beverage bottles, and pesticide bottles; and medical applications such as toothbrushes, chair legs and armrests, and sutures.

Claims

1. A molded article obtained by molding a resin composition containing a recycled polyester resin, ΔL is 9.5 or less, The haze of the solution of the molded body is 1.50% or more. Here, the ΔL is a value obtained by carrying out the following steps (1) to (6) in order: (1) The resin composition is heated to 270° C. using an extruder equipped with a T-die to form a film having a thickness of 200 μm; (2) The obtained film is punched into a dumbbell shape No. 2 according to JIS K 6251 to obtain a dumbbell; (3) The L value of the obtained dumbbell is measured using a colorimeter, and the obtained value is regarded as the L value before tension; (4) The dumbbell is stretched to 8.5 times its original size at 95° C. and 1000 mm / min in a tensile tester in accordance with JIS K 7113; (5) The L value of the stretched dumbbell is measured using the colorimeter, and the obtained value is regarded as the L value after stretching; (6) subtracting the L value before tension from the L value after tension, and the obtained difference is designated as ΔL; The haze of the solution of the molded body is a value measured by carrying out the following steps (7) to (8) in this order: (7) dissolving the molded body in hexafluoro-2-propanol to obtain a solution having a solid concentration of 0.05 g / mL; (8) Measure the haze of the resulting solution using a haze meter zeroed with the hexafluoro-2-propanol.

2. The molded article according to claim 1, wherein the melt flow rate (MFR) of the resin composition is 3.7 g / 10 min to 30.0 g / 10 min. The MFR is a value determined by measurement in accordance with JIS K 7210-1 under conditions of drying at 130° C. for 8 hours, a temperature of 270° C., and a load of 2.16 kg.

3. The molded body according to claim 1, wherein the molded body has a total light transmittance (TT) of 80% or more. Here, the total light transmittance (TT) of the molded article is a value obtained by measurement using a haze meter.

4. The molded article according to claim 1, wherein the recycled polyester-based resin comprises at least one selected from the group consisting of recycled [polycarbonate / polyethylene terephthalate], recycled [polyethylene terephthalate / glycol-modified polyethylene terephthalate], and recycled [polyethylene terephthalate / copolymerized polyethylene terephthalate].

5. The molded article according to any one of claims 1 to 4, wherein the molded article is in a bottle shape.

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