Molded body containing recycled polyester-based resin

Abstract

The present invention addresses the problem of providing a molded body that contains a recycled polyester-based resin, the molded body having excellent strength and reduced whitening. Provided is a molded body obtained by molding a resin composition containing a recycled polyester-based resin, wherein the haze of a solution of the molded body is 1.50% or more, and the haze of the molded body is 7.5 or less.

Description

Technical Field

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

Background Art

[0002] In recent years, from the viewpoints of resource recycling and environmental protection, recycling of resins has been demanded. However, polyester resins have a problem that the melt viscosity decreases and the strength deteriorates each time they are recycled. As a technique for solving such a problem, a technique of adding a chain extender (sometimes referred to as a "viscosity improver" or "Melt viscosity improver: MVI") is known (for example, Patent Documents 1 to 3).

[0003] Also, as a technique for increasing the melt viscosity of polyester resins, a technique called solid state polymerization (SSP) is known (for example, Patent Document 4).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the above-mentioned conventional techniques are not sufficient from the viewpoint of whitening of the molded article, and there is room for further improvement.

[0006] One embodiment of the present invention has been made in view of the above-mentioned problems, and its object is to provide a molded article containing recycled polyester resin that has excellent strength and reduced whitening. [Means for solving the problem]

[0007] The inventors of this invention have diligently studied and conducted research to solve the aforementioned problems, and as a result, have completed this invention.

[0008] In other words, 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, wherein the haze of the solution of the molded article is 1.50% or more, and the haze of the molded article is 7.5 % The following is true: Here, the haze of the solution of the molded body is a value measured by performing (1) to (2) below in order; (1) Dissolve the resin composition in hexafluoro-2-propanol to obtain a solution in which the concentration of the resin composition is 0.05 g / mL; (2) Using a haze meter zeroed with hexafluoro-2-propanol, measure the haze of the resulting molded product solution; The haze of the molded body is the value obtained by measuring it using a haze meter.

[0009] Furthermore, the whitening inhibitor for polyester resins according to one embodiment of the present invention includes a polymer (A) obtained by polymerizing a monomer mixture (A) containing (a) 10% to 60% by weight of epoxy group-containing monomers and (b) 40% to 90% by weight of epoxy group-free monomers.

[0010] Furthermore, a method for manufacturing a molded article according to one embodiment of the present invention includes the steps of preparing a recycled polyester resin composition and molding the recycled polyester resin composition, wherein the step of preparing the recycled polyester resin composition includes the steps of melt-kneading a whitening inhibitor for polyester resins and a polyester resin to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin, and carrying out solid-phase polymerization using the pellets, wherein the whitening inhibitor for polyester resins is (a) 10 by weight of epoxy group-containing monomers % The present invention comprises a polymer (A) obtained by polymerizing a monomer mixture (A) containing (b) 40% to 90% by weight of an epoxy group-free monomer, and (b) 60% by weight of an epoxy group-free monomer. [Effects of the Invention]

[0011] According to one embodiment of the present invention, a molded article containing a recycled polyester resin can be provided, which has excellent strength and reduced whitening. [Modes for carrying out the invention]

[0012] One embodiment of the present invention is described below, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications are possible within the scope of the claims. Furthermore, 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. Moreover, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic and patent documents mentioned herein are incorporated herein by reference. Furthermore, unless otherwise specified herein, "A to B" representing a numerical range means "A or greater (including A and greater than A) and B or less (including B and less than B)."

[0013] [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, wherein the haze of the solution of the molded article is 1.50% or more, and the haze of the molded article is 7.5 % The following is the molded body: Here, the haze of the solution of the molded body is a value measured by performing (1) to (2) below in order; (1) Dissolve the resin composition in hexafluoro-2-propanol to obtain a solution in which the concentration of the resin composition is 0.05 g / mL; (2) Using a haze meter zeroed with hexafluoro-2-propanol, measure the haze of the resulting molded product solution; The haze of the molded body is the value obtained by measuring it using a haze meter.

[0014] In this specification, "a molded article according to one embodiment of the present invention" may be referred to as "the present molded article." In this specification, "a resin composition containing recycled polyester resin" may be referred to as "a recycled polyester resin composition" or simply "a resin composition." The resin composition that is the raw material for the present molded article can also be said to be the resin composition according to one embodiment of the present invention. In this specification, "a resin composition according to one embodiment of the present invention" may be referred to as "the present resin composition."

[0015] This molded product has the advantages of excellent strength and reduced whitening.

[0016] This molded product 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 its manufacture. As a result, one embodiment of the present invention can contribute to achieving Sustainable Development Goals (SDGs), such as Goal 12, "Ensure sustainable consumption and production patterns."

[0017] [1-1. Resin composition] This molded article is formed by molding a resin composition containing a recycled polyester-based resin. It can also be said that this molded article contains a resin composition containing a recycled polyester-based resin.

[0018] (1-1-1. Recycled Polyester-Based Resin) In this specification, the "recycled polyester-based resin" refers to a polyester-based resin obtained by recycling the following (i) and / or (ii), etc.: (i) A polyester-based resin composition and / or molded article that has been once commercialized as a polyester-based resin composition and / or molded article and has been used and / or discarded; (ii) Waste polyester-based resin compositions and / or waste molded articles discharged during the manufacturing process of polyester-based resin compositions and / or molded articles.

[0019] On the other hand, a polyester-based resin that has never been commercialized may be referred to as a "virgin polyester-based resin" in this specification. The "recycled polyester-based resin" in this specification also includes a mixture obtained by mixing a "virgin polyester-based resin" with a recycled polyester-based resin.

[0020] In this specification, the "X resin obtained by recycling" may also be referred to as "recycled [X resin]".

[0021] The method for recycling a polyester-based resin is not particularly limited, and known methods can be used. For example, chemical recycling, material recycling, thermal recycling, etc. can be mentioned.

[0022] 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 alicyclic diol are linked by an ester reaction. The polyester resin may also be obtained by polycondensation of an aromatic dicarboxylic acid or its ester derivative component and a diol component such as an aliphatic diol or alicyclic diol by a known method.

[0023] Aromatic dicarboxylic acids are not particularly limited, but examples 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-ta-phenylenedicarboxylic acid, 2,5-pyridinedicarboxylic acid, and the like. As for the aromatic dicarboxylic acid, only one type may be used, or two or more types may be used in combination.

[0024] Aliphatic diols are not particularly limited, but examples 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 adduct diol, polyethylene oxide glycol, and polypropylene oxide glycol. Examples of alicyclic diols include 1,4-cyclohexanedimethanol, 4,4-dicyclohexylhydroxymethane, and 4,4'-dicyclohexylhydroxypropane. Only one type of diol component may be used, or two or more types may be used in combination.

[0025] The polyester resin may be a polymer formed by copolymerizing an aromatic dicarboxylic acid or its ester derivative component as the main component, an aliphatic diol, and another dicarboxylic acid or its ester derivative component or diol. Examples of other dicarboxylic acids include alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and 4,4'-dicyclohexyldicarboxylic acid.

[0026] The polyester resin may have structural components derived from trifunctional or higher monomers such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, and pyromellitic acid.

[0027] While there are no particular limitations on specific examples of recycled polyester resins, examples include recycled [polyethylene terephthalate], recycled [polypropylene terephthalate], recycled [polybutylene terephthalate], recycled [polyethylene-2,6-naphthalate], recycled [polybutylene naphthalate], recycled [poly-1,4-cyclohexylenedimethylene terephthalate], recycled [polyethylene-1,2-bis(phenoxy)ethane-4,4'-dicarboxylate], recycled [polyethylene isophthalate / terephthalate], recycled [polybutylene terephthalate / isophthalate], recycled [polybutylene terephthalate / decanedicarboxylate], recycled [polycyclohexanedimethylene 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 glycol components other than ethylene glycol.

[0028] From the viewpoint of moldability and mechanical properties, the polyester resin preferably contains one or more selected from the group consisting of (i) recycled [polypropylene terephthalate], recycled [polybutylene terephthalate], recycled [polyethylene-2,6-naphthalate], recycled [polybutylene naphthalate], recycled [poly-1,4-cyclohexylenedimethylene terephthalate] and recycled [polyester / polyether], and may consist only of one or more selected from the group; and (ii) more preferably contains one or more selected from the group consisting of recycled [polyethylene terephthalate] and recycled [polybutylene terephthalate], and may consist only of one or more selected from the group.

[0029] As the recycled polyester resin, a recycled polymer alloy obtained by recycling a polymer alloy obtained from a mixture of multiple polymers including a polyester resin may be used. Examples of recycled polymer alloys 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 consist only of one or more selected from the group. This configuration has the advantage of being readily available. Furthermore, copolymerized polyethylene terephthalate refers to a resin in which a component other than the two components that make up polyethylene terephthalate (a third component) is copolymerized.

[0030] (1-1-2. Whitening inhibitors) The molded article is preferably molded using a whitening inhibitor. In other words, the resin composition is preferably made to contain a whitening inhibitor. By molding using a whitening inhibitor, (i) the melt viscosity of the resin composition can be improved, thereby increasing the strength of the molded article made from the resin composition, and (ii) whitening of the molded article containing recycled polyester resin can be suppressed.

[0031] The whitening inhibitor is not particularly limited. For example, a whitening inhibitor for polyester resins having the following composition is preferably used: (a) 10 wt epoxy group-containing alkyl (meth)acrylate % A whitening inhibitor for polyester resins comprising a polymer (A) obtained by polymerizing a monomer mixture (A) containing (b) 40% to 90% by weight of epoxy group-free alkyl (meth)acrylate, and (b) 60% by weight.

[0032] As a whitening inhibitor, for example, a whitening inhibitor for polyester resins according to one embodiment of the present invention described in the section [2. Whitening Inhibitors] below, for example, a whitening inhibitor for polyester resins having the following composition, is also suitably used: a whitening inhibitor for polyester resins comprising a polymer (A) obtained by polymerizing a monomer mixture (A) containing (a) 10% to 60% by weight of epoxy group-containing monomers and (b) 40% to 90% by weight of epoxy group-free monomers.

[0033] (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)."

[0034] In this specification, "(a) epoxy group-containing monomer" means a monomer containing an epoxy group.

[0035] Epoxy groups exhibit good reactivity with the terminal functional groups of recycled polyester resins. Therefore, it is preferable that the whitening inhibitor contains (a) an epoxy group-containing monomer.

[0036] The present invention will now describe the case in which the resin composition contains a whitening inhibitor. In this case, during the manufacturing process of the resin composition containing the recycled polyester resin and the whitening inhibitor (for example, during the melt-kneading of the recycled polyester resin and the whitening inhibitor), the reactive functional groups (e.g., epoxy groups) in the polymer (A) contained in the whitening inhibitor may react with the terminal functional groups (e.g., hydroxyl groups or carboxyl groups) of the recycled polyester resin. This reaction may cause the molecular chains of the recycled polyester resin to elongate; this mechanism improves the melt viscosity of the resin composition and improves the strength of the molded article. Furthermore, the inclusion of the aforementioned polymer (A) in the whitening inhibitor may improve the dispersibility of the whitening inhibitor within the resin composition. This is presumed to suppress whitening of the molded article. However, the present invention is not limited in any way to these mechanisms and presumptions.

[0037] (a) The 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 description, the epoxy group-containing alkyl (meth)acrylate will be described as component (a).

[0038] (a) Examples of components include, but are not limited to, glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, 3,4-epoxycyclohexyl (meth)acrylate, allyl glycidyl ether, and β-methylglycidyl (meth)acrylate. (a) Only one component may be used, or two or more may be used in combination.

[0039] From the viewpoint of polymerization productivity, component (a) preferably contains one or more selected from the group consisting of (i) glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, 3,4-epoxycyclohexyl (meth)acrylate, and β-methylglycidyl (meth)acrylate, and may consist only of one or more selected from the group; and (ii) more preferably contains one or more selected from the group consisting of glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, and 3,4-epoxycyclohexyl (meth)acrylate. (iii) may consist of only one or more selected from the group, (iv) may consist of only one or more selected from the group consisting of glycidyl acrylate, glycidyl methacrylate, and 4-hydroxybutyl acrylate glycidyl ether, (v) may consist of only one or more selected from the group, (iv) may consist of only one or more selected from the group consisting of glycidyl acrylate and glycidyl methacrylate, (v) may most preferably consist of glycidyl methacrylate, or may consist of only glycidyl methacrylate.

[0040] The content of component (a) in monomer mixture (A) is not particularly limited, but is preferably 10% to 60% by weight of 100% by weight of 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 component (a) is within the above range, the effect of improving the melt viscosity of the resin composition can be good. As a result, the molded article has the advantage of being superior in moldability and strength. In this specification, "excellent moldability of the molded article" means that the thickness distribution of the molded article is more uniform.

[0041] In this specification, "(b) epoxy group-free monomer" refers to monomers other than "(a) epoxy group-containing monomer," i.e., monomers that do not contain epoxy groups.

[0042] (b) Component is preferably an alkyl (meth)acrylate that does not have a reactive functional group (for example, an epoxy group-free alkyl (meth)acrylate). Specific examples of alkyl (meth)acrylates that do not have a reactive functional group include alkyl (meth)acrylates having an alkyl group with 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.

[0043] (b) As for the component, only one of the monomers mentioned above may be used, or two or more may be used in combination.

[0044] (b) 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.

[0045] From the viewpoint of the 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 only of one or more selected from said 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 only of one or more selected from said group; (iii) still preferably contains one or more selected from the group consisting of methyl methacrylate and butyl methacrylate, and may consist only of one or more selected from said group; and (iv) most preferably contains methyl methacrylate, and may consist only of methyl methacrylate.

[0046] The content of component (b) in monomer mixture (A) is not particularly limited, but is preferably 40% to 90% by weight of 100% by weight of monomer mixture (A). The upper limit may be 85%, 80%, 75%, or 70% by weight, and the lower limit may be 45%, 50%, 55%, or 60% by weight. If the content of component (b) is within the above range, there is an advantage that the dispersibility of the whitening inhibitor in the resin composition may be improved. As a result, there is also an advantage that the whitening of the resulting molded article may be further suppressed.

[0047] The monomer mixture (A) preferably further comprises (c) vinyl monomers other than components (a) and (b) that are copolymerizable with components (a) and (b). In this specification, "(c) vinyl monomers other than components (a) and (b) that are copolymerizable with components (a) and (b)" may be referred to as "component (c)".

[0048] (c) Examples of components include one or more selected from the group consisting of vinyl cyanide compounds, aromatic vinyl compounds, (meth)acrylic acid, etc., but are not particularly limited.

[0049] Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.

[0050] The aromatic vinyl compounds are not particularly limited, but examples 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.

[0051] (c) As for the component, only one of the monomers mentioned above may be used, or two or more may be used in combination.

[0052] From the viewpoint of polymerization productivity, component (c) preferably contains one or more selected from the group consisting of (i) 4-methylstyrene, 3-methylstyrene, α-methylstyrene, and styrene, and may consist only of one or more selected from the group; (ii) more preferably contains one or more selected from the group consisting of 4-methylstyrene, α-methylstyrene, and styrene, and may consist only of one or more selected from the group; (iii) still preferably contains one or more selected from the group consisting of α-methylstyrene and styrene, and may consist only of one or more selected from the group; and (iv) most preferably contains styrene, and may consist only of styrene.

[0053] On the other hand, since it is possible to provide a molded article with further reduced whitening, it is preferable that the content of aromatic vinyl compounds (especially styrene) in the monomer mixture (A) be as low as possible. The content of aromatic vinyl compounds in 100% by weight of monomer mixture (A) 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. It is most preferable that the content of aromatic vinyl compounds in 100% by weight of monomer mixture (A) is 0% by weight, that is, it is most preferable that monomer mixture (A) does not contain aromatic vinyl compounds. Since it is possible to provide a molded article with further reduced whitening, the content of styrene in 100% by weight of monomer mixture (A) 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. It is most preferable that the monomer mixture (A) contains 0% by weight of styrene in 100% by weight, that is, it is most preferable that the monomer mixture (A) does not contain styrene.

[0054] The content of component (c) in monomer mixture (A) is not particularly limited, but is preferably 0 to 10% by weight of 100% by weight of monomer mixture (A). The upper limit may be 8% by weight or 5% by weight, and the lower limit may be 2% by weight or 4% by weight. If the content of component (c) is within the above range, there is the advantage of improved productivity.

[0055] From the viewpoint of balancing the thermal stability and productivity of the whitening inhibitor, and improving the melt viscosity of the resin composition, the number-average molecular weight of polymer (A) is preferably in the range of 2,000 to 6,000. The lower limit of the number-average molecular weight of 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 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 polymer (A) can be adjusted by using a chain transfer agent during the polymerization of polymer (A). In other words, it is preferable to use a chain transfer agent during the polymerization of polymer (A) in order to obtain polymer (A) having a number-average molecular weight within the above range. The number-average molecular weight of polymer (A) can be measured by gel permeation chromatography (GPC) and determined in terms of polystyrene-equivalent molecular weight. The method for measuring the number-average molecular weight of polymer (A) will be described in detail in the following examples.

[0056] The polymer (A) preferably has an average of 2 to 15 reactive functional groups per molecule. The lower limit may be 3 or more. The upper limit may be 13 or less, 11 or less, 9 or less, or 8 or less. When the number of reactive functional groups in polymer (A) is within the above range, the melt viscosity of the resin composition can be suitably improved without causing gelation and without impairing the mechanical properties, heat resistance, rheological properties, etc. of the molded article.

[0057] Polymer (A) is preferably a non-rubber polymer. A non-rubber polymer is a polymer that does not have cross-linking structures between its molecular chains. The advantage of polymer (A) being a non-rubber polymer is that the reaction between the reactive functional groups (e.g., epoxy groups) of polymer (A) and the terminal functional groups of the recycled polyester resin proceeds more efficiently, making it easier to improve the melt viscosity of the resin composition.

[0058] (Method for producing polymer (A)) The polymerization method for polymer (A) can be any known method and is not particularly limited. For example, bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., can be employed, but emulsion polymerization is preferred.

[0059] The polymer (A) is preferably a polymer obtained by emulsion polymerization. In other words, the production of the whitening inhibitor preferably includes a step of obtaining polymer (A) by emulsion polymerization. In this specification, "emulsion polymerization" means carrying out a polymerization reaction in the presence of an emulsifier, which will be described later. Furthermore, during the emulsion polymerization, the emulsifier may react to produce a salt derived from the emulsifier. Therefore, if polymer (A) is a polymer obtained by emulsion polymerization, polymer (A) may contain an emulsifier, which will be described later, and / or a salt derived from the emulsifier. In other words, a polymer containing an emulsifier, which will be described later, and / or a salt derived from the emulsifier can be considered a polymer obtained by emulsion polymerization.

[0060] When producing 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, it is preferable that the monomer mixture (A) contains a chain transfer agent.

[0061] Examples of chain transfer agents, though not particularly limited, include 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, trimethylolpropanetris(thioglycolate), and pentaerythritol tetrakis(thioglycolate); thiophenols; tetraethyl thiuram disulfide; pentanephenylethane; acrolein; methacrolein; allyl alcohol; carbon tetrachloride; ethylene bromide; styrene oligomers such as α-methylstyrene dimer; and terpinolenes. The chain transfer agent may be used alone or in combination of two or more types. The amount of chain transfer agent used should be appropriately set according to the desired number average molecular weight of polymer (A).

[0062] The emulsifiers (dispersants) that can be used in emulsion polymerization are not particularly limited, but include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Dispersants such as polyvinyl alcohol, alkyl-substituted cellulose, polyvinylpyrrolidone, and polyacrylic acid derivatives may also be used. The emulsifiers (dispersants) may be used individually or in combination of two or more.

[0063] When employing emulsion polymerization, a pyrolysis-type initiator can be used as a radical polymerization initiator. Examples of known pyrolysis-type initiators include 2,2'-azobisisobutyronitrile, hydrogen peroxide, potassium persulfate, and ammonium persulfate.

[0064] Redox-type initiators can also be used as radical polymerization initiators. The redox-type initiator is an initiator that combines (a) peroxides such as organic peroxides and inorganic peroxides, and (b) optionally a reducing agent such as sodium formaldehyde sulfoxylate or glucose, optionally a transition metal salt such as iron(II) sulfate, optionally a chelating agent such as disodium ethylenediaminetetraacetate, and optionally a phosphorus-containing compound such as sodium pyrophosphate. Examples of organic peroxides include t-butyl peroxyisopropyl carbonate, paramenthane hydroperoxide, cumene hydroperoxide, dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, and t-hexyl peroxide. Examples of inorganic peroxides include hydrogen peroxide, potassium persulfate, and ammonium persulfate.

[0065] When a redox-type initiator is used, polymerization can be carried out even at low temperatures in which the peroxide does not substantially decompose thermally, allowing the polymerization temperature to be set over a wide range. For this reason, it is preferable to use a redox-type initiator. Among redox-type initiators, those using organic peroxides such as cumene hydroperoxide, dicumyl peroxide, paramenthane hydroperoxide, and t-butyl hydroperoxide as peroxides are preferred. The amount of the initiator used, and the amounts of the reducing agent, transition metal salt, and chelating agent used when a redox-type initiator is used, can be used within known ranges.

[0066] Known surfactants can also be used in the polymerization of polymer (A).

[0067] When polymer (A) is produced by emulsion polymerization, a latex containing polymer (A) (e.g., aqueous latex) can be obtained. Polymer (A) can be obtained by separating polymer (A) from the latex containing polymer (A). The obtained polymer (A) can be used as a whitening inhibitor. There are no particular limitations on the method for separating polymer (A) from the latex containing polymer (A), but examples include salting out of polymer (A) using an acid and a metal salt, and precipitation of polymer (A) using an organic solvent. Polymer (A) separated from the latex containing polymer (A) may be washed and further dried. By separating polymer (A) from the latex containing polymer (A), washing, and further drying, a powder of polymer (A) (also referred to as "powder") can be obtained. Alternatively, a powder of polymer (A) can be obtained by spray drying the latex containing polymer (A). The polymer (A) powder obtained in this way can be used as a whitening inhibitor.

[0068] (Polymer (B)) The whitening inhibitor may or may not contain polymer (B) in addition to polymer (A). The polymer component in the whitening inhibitor may consist only of polymer (A), or only of polymer (A) and polymer (B), or may consist of polymer (A), polymer (B), and other polymers.

[0069] The case in which the whitening inhibitor contains polymer (A) and polymer (B) (hereinafter also referred to as "Case A") will be described below. In Case A, it is preferable to polymerize polymer (A) and then polymerize polymer (B) in the presence of polymer (A). In Case A, if polymer (A) is obtained by emulsion polymerization, for example, it is particularly preferable to produce polymer (B) in latex containing polymer (A) after producing polymer (A). When polymer (B) is produced in latex containing polymer (A), a composite consisting of polymer (A) and polymer (B) (or containing polymer (A) and polymer (B)) can be obtained. In the composite, polymer (B) may cover a part of polymer (A). Therefore, in the composite, polymer (A) can be referred to as the core part and polymer (B) as the shell part. The composite may have a core-shell structure in which polymer (A) is the core part and polymer (B) is the shell part. In other words, when polymer (B) is produced (polymerized) in latex containing polymer (A), a composite consisting of polymer (A) and polymer (B) can be obtained, in which polymer (A) forms the core and polymer (B) forms the shell, i.e., a composite having a core-shell structure. In the composite, polymer (B) may cover the entire polymer (A) or may be impregnated into the interior of particulate polymer (A).

[0070] When a whitening inhibitor contains polymer (A) and polymer (B), and the composite composed of polymer (A) and polymer (B) has a core-shell structure in which polymer (A) forms the core and polymer (B) forms the shell, it has the advantage of improving productivity.

[0071] Polymer (B) is not particularly limited. The composition of the constituent units of polymer (B) may be the same as or different from the composition of the constituent units of polymer (A). In other words, the composition of monomer mixture (B) may be the same as or different from the composition of monomer mixture (A).

[0072] The polymer (B) is preferably a polymer obtained by polymerizing a monomer mixture (B) containing (a) 10% to 60% by weight of epoxy group-containing monomers and (b) 40% to 90% by weight of epoxy group-free monomers. The polymer (B) is further preferably (c) containing 0% to 10% by weight of vinyl monomers other than components (a) and (b) that are copolymerizable with components (a) and (b).

[0073] It is preferable that the number-average molecular weight of polymer (B) is different from that of polymer (A). More preferably, the number-average molecular weight of polymer (B) is greater than that of polymer (A). This configuration raises the softening point of the polymer (composite) and can reduce the likelihood of problems such as sticking. As a result, it has the advantage of improving productivity.

[0074] It is preferable that polymer (B) is a non-rubber polymer. This configuration has the advantage that the reaction between the reactive functional groups of polymer (B) and the terminal functional groups of the recycled polyester resin proceeds more efficiently, and the melt viscosity of the resin composition tends to improve. In case A, it is preferable that (i) polymer (A) is a non-rubber polymer or polymer (B) is a non-rubber polymer, and it is more preferable that both polymer (A) and polymer (B) are non-rubber polymers (for example, the entire composite is a non-rubber polymer).

[0075] The following describes the case where the whitening inhibitor contains polymer (A) and polymer (B), and the composite composed of polymer (A) and polymer (B) has a core-shell structure in which polymer (A) forms the core and polymer (B) forms the shell (hereinafter also referred to as "Case B"). In Case A and Case B, the ratio of the weight of polymer (A) to the weight of polymer (B) in the composite (weight of polymer (A) / weight of 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 polymer (A) to the weight of polymer (B) in the composite is within the above range, there is the advantage that productivity is improved.

[0076] In case B, the number average molecular weight of 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 increased melt viscosity and suppression of whitening. In cases A and B, the number average molecular weight of 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.

[0077] The polymer (B) preferably has an average of 2 to 15 reactive functional groups per molecule. The lower limit may be 3 or more. The upper limit may be 13 or less, 11 or less, or 9 or less. When the number of reactive functional groups in polymer (B) is within the above range, the melt viscosity of the resin composition can be suitably improved without causing gelation and without impairing the mechanical properties, heat resistance, rheological properties, etc. of the molded article.

[0078] Polymer (A) and polymer (B) may differ in one or more aspects selected from the group consisting of the composition of constituent units, number-average molecular weight, average number of reactive functional groups per molecule, and epoxy equivalent.

[0079] (Method for producing polymer (B)) The polymerization method for polymer (B) can be any known method and is not particularly limited. For example, bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., can be used, but emulsion polymerization is preferred. When producing 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, it is preferable that the monomer mixture (B) contains a chain transfer agent.

[0080] With respect to polymer (B), the descriptions in section [Polymer (A)] may be applied as appropriate, except for the matters described above. For example, regarding the types and content of components (a), (b), and (c) contained in monomer mixture (B), preferred embodiments for polymer (A) (monomer mixture (A)) are also preferred for polymer (B) (monomer mixture (B)).

[0081] The whitening inhibitor is preferable if it contains a low amount of polymers with a molecular weight of 1000 or less. A lower content of polymers with a molecular weight of 1000 or less in the whitening inhibitor has the advantage of being more suitable for food applications.

[0082] The content of polymers with a molecular weight of 1000 or less in the whitening inhibitor is not particularly limited, but it 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 suitably applicable to food use. The lower limit of the content of polymers with a molecular weight of 1000 or less in the whitening inhibitor is 0.00% by weight, meaning that the whitening inhibitor does not need to contain polymers with a molecular weight of 1000 or less.

[0083] The whitening inhibitor is preferable to have a low content of polymer (A) with a molecular weight of 1000 or less. The content of polymer (A) with a molecular weight of 1000 or less in the whitening inhibitor is not particularly limited, but it 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, per 100% by weight of the whitening inhibitor. This configuration has the advantage of being suitably applicable to food applications. The lower limit of the content of polymer (A) with a molecular weight of 1000 or less in the whitening inhibitor is 0.00% by weight, meaning that the whitening inhibitor does not need to contain polymer (A) with a molecular weight of 1000 or less.

[0084] In case A, the whitening inhibitor is preferable to have a low content of polymer (B) with a molecular weight of 1000 or less. In case A, the content of polymer (B) with a molecular weight of 1000 or less in the whitening inhibitor is not particularly limited, but it 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, per 100% by weight of the whitening inhibitor. This configuration has the advantage of being suitably applicable to food use. In case A, the lower limit of the content of polymer (B) with a 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 (B) with a molecular weight of 1000 or less.

[0085] The content of the whitening inhibitor in the resin composition is not particularly limited. Preferably, the content of the whitening inhibitor in the resin composition is 0.1% to 10.0% by weight of 100% by weight of the resin composition. More preferably, the lower limit of the content is 0.2% by weight or more. The upper limit of the content may be 8.0% by weight or less, 6.0% by weight or less, or 4.0% by weight or less. If the content of the whitening inhibitor in the resin composition is within the above range, there is an advantage in that a good balance is achieved between improving melt viscosity and suppressing whitening.

[0086] In a resin composition, the recycled polyester resin and the whitening inhibitor may react. More specifically, in the resin composition, the reactive functional group (e.g., epoxy group) of the reactive functional group-containing unit in polymer (A) contained in the whitening inhibitor may react with the terminal functional group (e.g., hydroxyl group or carboxyl group) of the recycled polyester resin. As a result of such a reaction, a resin having constituent units derived from the recycled polyester resin and constituent units derived from the whitening inhibitor may be formed. Therefore, in the resin composition, (i) at least a portion of the recycled polyester resin may react with the whitening inhibitor and exist as constituent units derived from the recycled polyester resin, (ii) at least a portion of the whitening inhibitor may react with the recycled polyester resin and exist as constituent units derived from the whitening inhibitor, and (iii) in the constituent units derived from the whitening inhibitor, for example, the epoxy group of polymer (A) may exist in a state of covalent bonding with the terminals of constituent units derived from the recycled polyester resin. In this specification, "the resin composition comprises a recycled polyester resin and a whitening inhibitor" also includes cases in the resin composition where the recycled polyester resin and the whitening inhibitor exist as constituent units derived from the recycled polyester resin and the whitening inhibitor, respectively.

[0087] (1-1-3. Other resins) This resin composition may or may not contain resins other than recycled polyester resins. The resins other than recycled polyester resins are not particularly limited, but examples include virgin polyester resins, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, polytetrafluoroethylene, ABS resin, AS resin, acrylic resin, polyacetal, polycarbonate, modified polyphenylene ether, polyamide, cyclic polyolefin, and the like.

[0088] The content of resins other than recycled polyester resin in this resin composition is not particularly limited, but for example, it may be 0 to 60 parts by weight per 100 parts by weight of recycled polyester resin. The upper limit of the content may be any of the following: 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.

[0089] In this resin composition, there are no particular limitations on the content of resins other than polyester resins, including recycled polyester resins and virgin polyester resins. In this resin composition, the content of resins other than polyester resins relative to 100 parts by weight of polyester resin, i.e., 100 parts by weight of the total amount of recycled polyester resin and virgin polyester resin, may be between 0 and 60 parts by weight. The upper limit of the content may be any of the following: 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.

[0090] (1-1-4. Other Additives) The molded article may be molded using other additives. In other words, the resin composition may contain other additives. Other additives are not particularly limited, but examples include flame retardants, flame retardant enhancers, anti-dripping agents, reinforcing agents, fillers, antioxidants, pigments, dyes, conductivity imparters, hydrolysis inhibitors, thickeners, plasticizers, lubricants, ultraviolet absorbers, antistatic agents, flow improvers, mold release agents, compatibilizers, and heat stabilizers.

[0091] (1-1-5. Method for producing resin compositions) The method for producing this resin composition is not particularly limited, and general resin composition production methods can be applied. For example, the resin composition can be obtained by mixing raw materials (e.g., recycled polyester resin and a whitening inhibitor) using a Henschel mixer or tumbler mixer, and then melt-kneading the resulting mixture. A kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a pressure kneader, or a mixing roll can be used for this melt-kneading. Pellets made from the resin composition can be produced by such melt-kneading.

[0092] (1-1-6. Physical properties of resin compositions) The higher the melt viscosity (IV value) of the resin composition, the stronger the molded article it can provide. In other words, it is preferable that the resin composition 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 following examples.

[0093] The lower the MFR of the resin composition, the better the strength of the molded article it can provide. In other words, it is preferable that the resin composition has a low MFR.

[0094] The melt flow rate (MFR) of the resin composition is preferably 3.7 g / 10 min to 30.0 g / 10 min, more preferably 3.7 g / 10 min to 29.5 g / 10 min, more preferably 3.7 g / 10 min to 29.0 g / 10 min, more preferably 3.7 g / 10 min to 28.5 g / 10 min, even more preferably 3.7 g / 10 min to 28.0 g / 10 min, and particularly preferably 3.7 g / 10 min to 27.5 g / 10 min. When the melt flow rate (MFR) of the resin composition is within the above range, the molded article has the advantage of excellent strength. The method for measuring the MFR of the resin composition will be described in detail in the following examples.

[0095] A technique called solid-phase polymerization (SSP) is known as a method for improving the melt viscosity (IV value) of recycled polyester resins. Molded articles made from a resin composition obtained by solid-phase polymerization using recycled polyester resin as a raw material have the advantage of not whitening at all, or if whitening occurs, the degree of whitening is very small. However, solid-phase polymerization is carried out in a vacuum and at high temperatures for a long time, so it requires a huge amount of energy. The haze of a solution obtained by dissolving a molded article 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 article obtained from this resin composition is, for example, 1.50% or more. In other words, if the haze of the solution obtained by dissolving the molded article is 1.50% or more, the molded article can be considered not to be a molded article obtained from a resin composition obtained by solid-phase polymerization. In one embodiment of the present invention, the haze of the solution obtained by dissolving the molded article may be 2.00% or more, 2.50% or more, or 3.00% or more.

[0096] [1-2. Method for manufacturing molded articles] The method for manufacturing the molded article, in other words, the method for molding the resin composition, is not particularly limited. For example, injection molding, extrusion molding, blow molding, calendering, inflation molding, rotational molding, press molding, etc., can be used for manufacturing the molded article (method for molding the resin composition). Among these, blow molding is preferred. In other words, the molded article according to one embodiment of the present invention is preferably a molded article obtained by blow molding the resin composition.

[0097] In this specification, the blow molding method may be a molding method that performs blow molding using a resin composition alone, or it may be a molding method that is performed in combination with other molding methods (e.g., injection molding, extrusion molding, calendering, etc.). As a molding method performed in combination with other molding methods, the two-step blow molding method is preferred. The two-step blow molding method is a molding method in which, in the first step, a resin composition is injection molded to obtain an injection molded article, and in the second step, the injection molded article is blow molded.

[0098] [1-3. Physical properties of molded articles] The degree of whitening of a molded article can be evaluated by the difference in L values ​​(ΔL) before and after tensile testing of a film (molded article) formed by molding a resin composition into a film. Specifically, a resin composition is molded into a film, and a tensile test is performed on the resulting film (molded article). A smaller difference in L values ​​(ΔL) before and after tensile testing indicates that the whitening of the molded article obtained using that resin composition is reduced. For example, in blow molding of a resin composition or injection-molded article, the resin composition or injection-molded article is molded while being stretched. The stretching of the film (molded article) in the tensile test can be said to mimic the stretching of the resin composition or injection-molded article during blow molding. Therefore, a smaller ΔL of the film (molded article) indicates that the whitening of the blow-molded article (e.g., a bottle-shaped molded article) obtained by blow molding is reduced.

[0099] In one embodiment of the present invention, ΔL is preferably 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. A ΔL within the above range means that whitening of the molded article is suppressed. The method for measuring the ΔL of the film (molded article) will be described in detail in a later example.

[0100] The haze of this molded product is 7.5 % Preferably, it is as follows: 6.5 % It is more preferable that the following be the case: 5.5 % It is more preferable that it be 5.0 % It is more preferable that the following apply: 4.5 % It is even more preferable that the following apply: 4.0 % The following is particularly preferable: The lower limit of the haze of the molded article is not particularly limited, for example, 1.0 %Therefore, a haze of the molded product within the above range indicates high transparency of the molded product. The method for measuring the haze of the molded product will be explained in detail in a later example.

[0101] The total light transmittance (TT) of the molded article is preferably 80.0% or higher, more preferably 80.5% or higher, more preferably 81.0% or higher, more preferably 81.5% or higher, even more preferably 82.0% or higher, and particularly preferably 82.5% or higher. The upper limit of the total light transmittance (TT) of the molded article is not particularly limited and is, for example, 100%. A total light transmittance (TT) of the molded article being within the above range means that the molded article has high transparency. The method for measuring the total light transmittance (TT) of the molded article will be described in detail in the following examples.

[0102] The base of this molded body Tired The strength 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, it has the advantage of broadening the range of applications in which the molded article can be used. The method for measuring the buckling strength of the molded article will be described in detail in the following examples.

[0103] [1-4. Shape of the molded body] The shape of the molded article is not particularly limited. By using the resin composition and the various molding methods described above, molded articles of various shapes can be produced. Examples of molded article shapes include bottle shape, sheet shape, film shape, and rod shape. Among these, the molded article is preferably bottle-shaped, more preferably a blow-molded product (molded article) obtained by blow molding, and particularly preferably a blow-molded product in the shape of a bottle (a molded article in the shape of a bottle) obtained by blow molding.

[0104] [2. Whitening inhibitors] One embodiment of the present invention provides a whitening inhibitor.

[0105] Conventional viscosity modifiers improve the melt viscosity of a resin composition to a certain extent when mixed with a matrix resin (e.g., a polyester resin), but they also have the problem of causing whitening of molded articles made from the resulting resin composition. To address this problem, conventional methods have aimed to make the refractive index of the matrix resin as close as possible to that of the polymer, which is the main component of the viscosity modifier. For example, when the matrix resin is a polyester resin, there was a technique to use a monomer mixture containing a certain amount of styrene in addition to a monomer containing reactive functional groups during polymerization of the polymer. The resin composition obtained in this way had a certain degree of transparency because the refractive index of the polyester resin and the refractive index of the polymer were equal. However, even when using such a resin composition, the problem of whitening of the molded article still remained.

[0106] An embodiment of the present invention also aims to provide a novel whitening inhibitor for polyester resins that can provide a polyester resin composition capable of providing a molded article with excellent strength and reduced whitening.

[0107] The inventors diligently conducted research without being limited by refractive index in order to obtain a molded article with reduced whitening. As a result, the inventors have uniquely obtained a novel finding that a whitening inhibitor containing a polymer (A) according to one embodiment of the present invention, which is obtained by polymerizing a monomer mixture (A) containing specific amounts of each of components (a), (b), and (c), or a monomer mixture (A) containing specific amounts of each of components (a) and (b), can provide a molded article with reduced whitening.

[0108] In other words, according to one embodiment of the present invention, a polyester resin composition can be provided that can provide a molded article with excellent strength and reduced whitening, and a whitening inhibitor for polyester resins can be provided.

[0109] [2-1. Whitening inhibitor for polyester resins] A whitening inhibitor for polyester resins according to one embodiment of the present invention comprises a polymer (A) obtained by polymerizing a monomer mixture (A) containing (a) 10% to 60% by weight of an epoxy group-containing monomer and (b) 40% to 90% by weight of an epoxy group-free monomer.

[0110] In this specification, "whitening inhibitor for polyester resins" may be referred to simply as "whitening inhibitor."

[0111] The whitening inhibitor according to one embodiment of the present invention has the advantage of being able to provide a polyester resin composition that can provide a molded article with excellent strength and reduced whitening, because it has the above configuration. It can also be said that the whitening inhibitor according to one embodiment of the present invention can provide a molded article with excellent strength and reduced whitening, because it has the above configuration.

[0112] The specific embodiments of the whitening inhibitor are the same as those described in section (1-1-2. Whitening Inhibitor) above, so we will refer to that description and omit the explanation here. The embodiments described as preferred embodiments in section (1-1-2. Whitening Inhibitor) above are also preferred embodiments in this section [2-1. Whitening Inhibitor for Polyester Resins].

[0113] Furthermore, when referring to the description in section (1-1-2. Whitening Inhibitors) above as an explanation in section [2-1. Whitening Inhibitors for Polyester Resins], the term "recycled polyester resin" in section (1-1-2. Whitening Inhibitors) above may be read as "polyester resin" in the explanation in section [2-1. Whitening Inhibitors for Polyester Resins], and the term "resin composition" in section (1-1-2. Whitening Inhibitors) above may be read as "polyester resin composition" in the explanation in section [2-1. Whitening Inhibitors for Polyester Resins].

[0114] [2-2. Polyester resin compositions] A polyester resin composition according to one embodiment of the present invention comprises a whitening inhibitor according to one embodiment of the present invention described in section [2-1. Whitening inhibitor for polyester resin], that is, the whitening inhibitor described in section (1-1-2. Whitening inhibitor), and a polyester resin.

[0115] A polyester resin composition according to one embodiment of the present invention has the advantage of being able to provide a molded article with excellent strength and reduced whitening, because it has the above-mentioned structure.

[0116] As described above, the whitening inhibitor according to one embodiment of the present invention can react not only with recycled polyester resins but also with virgin polyester resins. Specifically, the reactive functional group (e.g., epoxy group) in polymer (A) contained in the whitening inhibitor can react with the terminal functional group (e.g., hydroxyl group or carboxyl group) of the polyester resin. This reaction can elongate the molecular chain of the virgin polyester resin. In other words, the whitening inhibitor according to one embodiment of the present invention can react with all polyester resins, whether recycled or virgin (unused), and can elongate the molecular chain of the polyester resin. Therefore, by mixing the whitening inhibitor according to one embodiment of the present invention with a polyester resin to form a polyester resin composition, (i) the melt viscosity of the polyester resin composition can be improved, thereby increasing the strength of the molded article made from the polyester resin composition, and (ii) whitening of the molded article containing the polyester resin can be suppressed.

[0117] (2-2-1. Polyester resin) Specific examples of polyester resins are not particularly limited, but include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polybutylene naphthalate, poly-1,4-cyclohexylenedimethylene terephthalate, polyethylene-1,2-bis(phenoxy)ethane-4,4'-dicarboxylate, polyethylene isophthalate / terephthalate, polybutylene terephthalate / isophthalate, polybutylene terephthalate / decanedicarboxylate, polycyclohexanedimethylene terephthalate / isophthalate, polyester / polyether, 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.

[0118] From the viewpoint of moldability and mechanical properties, the polyester resin preferably contains (i) one or more selected from the group consisting of polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polybutylene naphthalate, poly-1,4-cyclohexylenemethylene terephthalate, and polyester / polyether, and may consist only of one or more selected from this group; and (ii) it is more preferably to contain one or more selected from the group consisting of polyethylene terephthalate and polybutylene terephthalate, and may consist only of one or more selected from this group.

[0119] As the polyester resin, a polymer alloy obtained from a mixture of multiple polymers including the polyester resin may be used. Examples of polymer alloys include polycarbonate / polyethylene terephthalate, polyethylene terephthalate / glycol-modified polyethylene terephthalate, and polyethylene terephthalate / copolymerized polyethylene terephthalate. In other words, the polyester resin may contain one or more selected from the group consisting of polycarbonate / polyethylene terephthalate, polyethylene terephthalate / glycol-modified polyethylene terephthalate, and polyethylene terephthalate / copolymerized polyethylene terephthalate, or may consist only of one or more selected from the group. Note that copolymerized polyethylene terephthalate refers to a resin in which a component other than the two components constituting polyethylene terephthalate (a third component) is copolymerized.

[0120] Regarding aspects of polyester resins other than those described above, they are the same as those described in section (1-1-1. Recycled Polyester Resins) above, so we will refer to that description and omit further explanation here. In particular, among the aspects described in section (1-1-1. Recycled Polyester Resins) above, aspects other than recycling can be considered aspects relating to polyester resins and applied as appropriate. The aspects described as preferred in section (1-1-1. Recycled Polyester Resins) above are also preferred in section (2-2-1. Polyester Resins).

[0121] Conventionally, when recycling the following (i) and (ii), the resulting melt viscosity tends to decrease due to moisture and / or heating during the recycling process.

[0122] (i) Polyester resin compositions and / or molded articles that have been commercialized as polyester resin compositions and / or molded articles, and have been used and / or discarded; (ii) Waste polyester resin compositions and / or waste molded articles discharged during the manufacturing process of polyester resin compositions and / or molded articles.

[0123] In other words, recycled polyester resins tend to have a lower melt viscosity compared to unused materials. Therefore, conventionally, recycled polyester resins have tended to have limited reuse applications due to their low melt viscosity. Furthermore, when using recycled polyester resins, a technique was known to improve the melt viscosity of a resin composition containing recycled polyester resin to a certain extent by adding a viscosity modifier to the recycled polyester resin. However, molded articles obtained from conventional resin compositions containing viscosity modifiers had the problem of whitening. Therefore, due to the whitening of the resulting molded articles, the reuse applications of recycled polyester resins tended to be limited. However, the whitening inhibitor according to one embodiment of the present invention has the advantage of being able to improve the melt viscosity of the resulting resin composition when mixed with recycled polyester resin, and providing a molded article with reduced whitening. Therefore, one embodiment of the present invention has the advantage of greatly expanding the applications of recycled polyester resins, and in particular, can greatly contribute to their development in applications that require strength and high transparency (for example, alcoholic beverage bottles, beverage bottles, etc.).

[0124] When the polyester resin includes recycled polyester resin, one embodiment of the present invention can significantly reduce the amount of plastic waste generated and the amount of plastic used in its manufacture. As a result, one embodiment of the present invention can contribute to achieving Sustainable Development Goals (SDGs), such as Goal 12, "Ensure sustainable consumption and production patterns."

[0125] In the polyester resin composition according to one embodiment of the present invention, the content of the whitening inhibitor is not particularly limited. In the polyester resin composition according to one embodiment of the present invention, the content of the whitening inhibitor is preferably 0.1% to 10.0% by weight of 100% by weight of the polyester resin composition. The lower limit of the content is more preferably 0.2% by weight or more. The upper limit of the content may be 8.0% by weight or less, 6.0% by weight or less, or 4.0% by weight or less. If the content of the whitening inhibitor in the polyester resin composition is within the above range, there is an advantage that a good balance is achieved between improving melt viscosity and suppressing whitening.

[0126] A polyester resin composition according to one embodiment of the present invention may be a masterbatch containing 10.0% to 90.0% by weight of a whitening inhibitor in 100% by weight of the resin composition. It can also be said that a polyester resin composition containing 10.0% to 90.0% by weight of a whitening inhibitor in 100% by weight of the polyester resin composition can be used as a masterbatch. When using a polyester resin composition according to one embodiment of the present invention as a masterbatch, the content of the whitening inhibitor in the polyester resin composition is preferably 10.0% to 90.0% by weight in 100% by weight of the polyester resin composition. The lower limit of the content is more preferably 20.0% by weight or more. The upper limit of the content may be 80.0% by weight or less. If the content of the whitening inhibitor in the polyester resin composition is within the above range, there is an advantage that the dispersibility of the whitening inhibitor in the polyester resin is good when used as a masterbatch.

[0127] The method for manufacturing the masterbatch is not particularly limited and can include, for example, a melt-kneading method or a dry-blending method, but the melt-kneading method is particularly preferred.

[0128] (2-2-2. Other resins) The polyester resin composition according to one embodiment of the present invention may or may not further contain resins other than polyester resins. Specific examples of resins other than polyester resins are the same as those described in section (1-1-3. Other Resins) above, so that description is used and the explanation is omitted here.

[0129] The content of resins other than polyester resin in the polyester resin composition according to one embodiment of the present invention is not particularly limited, but for example, it may be 0 to 60 parts by weight per 100 parts by weight of polyester resin. The upper limit of the content may be any of 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.

[0130] (2-2-3. Other Additives) The polyester resin composition according to one embodiment of the present invention may contain other additives. Specific examples of other additives are the same as those described in section (1-1-4. Other Additives) above, and therefore, that description is used as a reference and the explanation is omitted here.

[0131] (2-2-4. Method for producing resin compositions) The method for producing the polyester resin composition according to one embodiment of the present invention is not particularly limited, and a general method for producing resin compositions can be applied. For example, the method described in section (1-1-5. Method for producing resin composition) can be adopted, except that a polyester resin (recycled polyester resin and / or virgin polyester resin) is used instead of a recycled polyester resin.

[0132] (2-2-5. Physical properties of polyester resin compositions) A whitening inhibitor according to one embodiment of the present invention can provide a polyester resin composition that can provide a molded article with excellent strength and reduced whitening. Furthermore, a polyester resin composition according to one embodiment of the present invention (a resin composition comprising a whitening inhibitor and a polyester resin according to one embodiment of the present invention) can provide a molded article with excellent strength and reduced whitening.

[0133] The higher the melt viscosity (IV value) of a polyester resin composition, the stronger the molded article the resin composition can provide. In other words, the whitening inhibitor according to one embodiment of the present invention can provide a resin composition with a higher melt viscosity (IV value) compared to a resin or resin composition that does not contain the whitening inhibitor, and / or compared to a conventional resin composition that contains a viscosity improver. The polyester resin composition according to one embodiment of the present invention has the advantage of having a higher melt viscosity (IV value) compared to a resin or resin composition that does not contain the whitening inhibitor according to one embodiment of the present invention, and / or compared to a conventional resin composition that contains a viscosity improver. The method for measuring the melt viscosity (IV value) of the polyester resin composition will be described in detail in the following examples.

[0134] The lower the MFR of a polyester resin composition, the stronger the molded article the resin composition can provide. In other words, the whitening inhibitor according to one embodiment of the present invention can provide a resin composition with a lower MFR compared to a resin or resin composition that does not contain the whitening inhibitor, and / or compared to a conventional resin composition that contains a viscosity modifier. The polyester resin composition according to one embodiment of the present invention has the advantage of having a lower MFR compared to a resin or resin composition that does not contain the whitening inhibitor according to one embodiment of the present invention, and / or compared to a conventional resin composition that contains a viscosity modifier. The method for measuring the MFR of a polyester resin composition will be described in detail in the following examples.

[0135] [2-3. Molded body] A molded article according to one embodiment of the present invention is a molded article obtained by molding the polyester resin composition according to one embodiment of the present invention described in the section [2-2. Polyester Resin Composition] above. A molded article according to one embodiment of the present invention can also be said to be a molded article containing the polyester resin composition according to one embodiment of the present invention described in the section [2-2. Polyester Resin Composition] above.

[0136] A molded article according to one embodiment of the present invention has the advantages of having excellent strength and reduced whitening, due to the above configuration.

[0137] (2-3-1. Method for manufacturing molded articles) The method for manufacturing a molded article according to one embodiment of the present invention, in other words, the method for molding a polyester resin composition according to one embodiment of the present invention, is not particularly limited. The method for manufacturing a molded article may be the same as the method described in section [1-2. Method for manufacturing a molded article] above. Therefore, referring to the description in section [1-2. Method for manufacturing a molded article] above, the explanation will be omitted here. The molded article according to one embodiment of the present invention is preferably a molded article obtained by blow molding a polyester resin composition according to one embodiment of the present invention described in section [2-2. Polyester resin composition] above.

[0138] (2-3-2. Physical properties of molded articles) The degree of whitening of a molded article can be evaluated by the difference in L value (ΔL) before and after tensile testing of a film (molded article) obtained by molding a resin composition into a film. Specifically, a resin composition is molded into a film, and a tensile test is performed on the obtained film (molded article). The smaller the difference in L value (ΔL) before and after tensile testing, the more the resin composition can provide a molded article with reduced whitening. For example, in blow molding of a resin composition or injection-molded article, the resin composition or injection-molded article is molded while being stretched. The stretching of the film (molded article) in the tensile test can be said to mimic the stretching of the resin composition or injection-molded article during blow molding. Therefore, the smaller the ΔL of the film (molded article), the less whitening is found in the blow-molded article (e.g., a bottle-shaped molded article) obtained by blow molding. A film (molded article) according to one embodiment of the present invention has the advantage of having a smaller ΔL compared to a film (molded article) obtained from a conventional resin composition containing a viscosity modifier. In other words, this whitening inhibitor and this resin composition have the advantage of being able to provide films (molded articles) with a smaller ΔL compared to conventional resin compositions containing viscosity modifiers.

[0139] Since ΔL is the same as that described in section [1-3. Physical Properties of Molded Articles] above, we will refer to that description and omit the explanation here. The preferred numerical range for ΔL described in section [1-3. Physical Properties of Molded Articles] above can also be said to be a preferred numerical range for ΔL in this section (2-3-2. Physical Properties of Molded Articles).

[0140] The haze, total light transmittance (TT), and flexural strength of the molded article according to one embodiment of the present invention are the same as those described in section [1-3. Physical Properties of the Molded Article] above, so we will refer to that description and omit the explanation here. The preferred numerical ranges for the haze, total light transmittance (TT), and flexural strength of the molded article described in section [1-3. Physical Properties of the Molded Article] above can also be said to be preferred numerical ranges for the haze, total light transmittance (TT), and flexural strength of the molded article in this section (2-3-2. Physical Properties of the Molded Article).

[0141] (2-3-3. Shape of the molded body) The shape of the molded article according to one embodiment of the present invention is not particularly limited. The shape of the molded article according to one embodiment of the present invention may be, for example, any of the shapes described in the section [1-4. Shape of the molded article] above. Therefore, the description in the section [1-4. Shape of the molded article] above can be appropriately referred to regarding the shape of the molded article according to one embodiment of the present invention. The embodiments described as preferred embodiments in the section [1-4. Shape of the molded article] above are also preferred embodiments in this section (2-3-3. Shape of the molded article).

[0142] [3. Method for producing recycled polyester resin composition] One embodiment of the present invention provides a method for producing a recycled polyester resin composition.

[0143] Polyester resins have a problem in that their melt viscosity decreases and their strength deteriorates with each recycling. Solid-phase polymerization (sometimes referred to as "SSP" in this specification), a known technique for increasing the melt viscosity of polyester resins, requires long periods of time under high temperature and reduced pressure (vacuum), resulting in high power consumption, environmental impact, and high production costs.

[0144] On the other hand, conventional methods for increasing the melt viscosity of polyester resins, such as adding viscosity modifiers, have the problem that while mixing the matrix resin (polyester resin) with the viscosity modifier improves the melt viscosity of the resin composition to a certain extent, the resulting molded product tends to whiten. To address this problem, conventional methods have attempted to make the refractive index of the matrix resin as similar as possible to that of the polymer, which is the main component of the viscosity modifier. For example, when the matrix resin is a polyester resin, there was a technique to use a monomer mixture containing a certain amount of styrene in addition to a monomer containing reactive functional groups during polymerization of the polymer. The resin composition obtained in this way had a certain degree of transparency because the refractive index of the polyester resin and the refractive index of the polymer were similar. However, even when using such a resin composition, the problem of whitening of the molded product still persisted.

[0145] An embodiment of the present invention also aims to provide a novel method for producing recycled polyester resin compositions that utilizes SSP while minimizing environmental impact and production costs.

[0146] The inventors diligently conducted research without being constrained by refractive index in order to obtain molded articles with reduced whitening. As a result, the inventors have uniquely obtained a novel finding that a whitening inhibitor containing a polymer (A) according to one embodiment of the present invention, which is obtained by polymerizing a monomer mixture (A) containing specific amounts of each of components (a), (b), and (c), or a monomer mixture (A) containing specific amounts of each of components (a) and (b), can provide molded articles with reduced whitening. Furthermore, when SSP was performed using pellets obtained by melt-kneading such whitening inhibitor with a polyester resin, it was found that the time required to raise the melt viscosity to the target value could be significantly shortened.

[0147] In other words, according to one embodiment of the present invention, it is possible to provide a novel method for producing recycled polyester resin compositions that utilizes SSP while having low environmental impact and production costs.

[0148] [3-1. Method for producing recycled polyester resin composition] A method for producing a recycled polyester resin composition according to one embodiment of the present invention includes the steps of: preparing pellets containing a whitening inhibitor for polyester resins and a polyester resin by melt-kneading the polyester resin and the polyester resin; and carrying out solid-phase polymerization using the pellets, wherein the whitening inhibitor for polyester resins is (a) 10 by weight of epoxy group-containing monomer % The present invention comprises a polymer (A) obtained by polymerizing a monomer mixture (A) containing (b) 40% to 90% by weight of an epoxy group-free monomer, and (b) 60% by weight of an epoxy group-free monomer.

[0149] In this specification, the step of "melt-kneading a whitening inhibitor for polyester resins and a polyester resin to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin" may be referred to as "Step I," and the step of "carrying out solid-phase polymerization using the pellets" may be referred to as "Step II." In addition, the "whitening inhibitor for polyester resins" may be simply referred to as "whitening inhibitor," and the "pellets containing the whitening inhibitor for polyester resins and the polyester resin" may be simply referred to as "pellets."

[0150] (3-1-1. Process I) (3-1-1-1. Whitening inhibitor) In one embodiment of the present invention, the whitening inhibitor comprises a polymer (A) obtained by polymerizing a monomer mixture (A) comprising (a) 10% to 60% by weight of an epoxy group-containing monomer and (b) 40% to 90% by weight of an epoxy group-free monomer.

[0151] Because the whitening inhibitor has the above-described structure, when melt-kneaded with a polyester resin, it increases the melt viscosity of the polyester resin, providing pellets that can provide molded articles with excellent strength and reduced whitening. Therefore, in SSP using pellets with increased melt viscosity, the time required to increase the melt viscosity to the target value can be shortened. Furthermore, because the whitening inhibitor has the above-described structure, it can also be said that it can provide molded articles with excellent strength and reduced whitening.

[0152] In the process of preparing pellets containing a polyester resin and a whitening inhibitor (for example, during the melt-kneading of the polyester resin and the whitening inhibitor), the reactive functional groups (e.g., epoxy groups) in polymer (A) contained in the whitening inhibitor may react with terminal functional groups (e.g., hydroxyl groups or carboxyl groups) of the polyester resin. This reaction can elongate the molecular chains of the polyester resin; this mechanism increases the melt viscosity of the pellets. As a result of the increased melt viscosity of the pellets, the time required to raise the melt viscosity to the target value in SSP using these pellets can be shortened. Furthermore, the inclusion of the aforementioned polymer (A) in the whitening inhibitor may improve the dispersibility of the whitening inhibitor within the pellets and in the recycled polyester resin composition after SSP. This is presumed to suppress whitening of the molded article. However, the present invention is not limited in any way to these mechanisms and presumptions.

[0153] The content of component (a) ((a) epoxy group-containing monomer) in monomer mixture (A) is not particularly limited, but is preferably 10% to 60% by weight of 100% by weight of monomer mixture (A). The upper limit of the content may be 55%, 50%, 45%, or 40% by weight, and the lower limit of the content may be 15%, 20%, 25%, or 30% by weight. If the content of component (a) is within the above range, the effect of improving the melt viscosity of the pellet can be good. As a result, the time required to raise the melt viscosity to the target value in SSP using the pellet can be shortened. Furthermore, the molded article obtained using the recycled polyester resin composition obtained after SSP has the advantage of superior strength.

[0154] The content of component (b) ((b) epoxy group-free monomer) in monomer mixture (A) is not particularly limited, but is preferably 40% to 90% by weight of 100% by weight of monomer mixture (A). The upper limit of the content may be 85% by weight, 80% by weight, 75% by weight, or 70% by weight, and the lower limit of the content may be 45% by weight, 50% by weight, 55% by weight, or 60% by weight. If the content of component (b) is within the above range, there is an advantage that the dispersibility of the whitening inhibitor in the pellets and in the recycled polyester resin composition after SSP may be improved. As a result, there is also an advantage that the whitening of the resulting molded article may be further suppressed.

[0155] Regarding embodiments of the whitening inhibitor other than those described above, they are the same as those described in section (1-1-2. Whitening Inhibitor) above, so we will refer to that description and omit the explanation here. The embodiments described as preferred embodiments in section (1-1-2. Whitening Inhibitor) above are also preferred embodiments in section (3-1-1-1. Whitening Inhibitor).

[0156] Furthermore, when referring to the description in section (1-1-2. Whitening Inhibitors) above as an explanation in section (3-1-1-1. Whitening Inhibitors) of this document, the term "recycled polyester resin" in section (1-1-2. Whitening Inhibitors) above may be read as "polyester resin" in the explanation in section (3-1-1-1. Whitening Inhibitors) of this document.

[0157] (3-1-1-2. Polyester resin) Specific examples of polyester resins are the same as those described in section (2-2-1. Polyester Resins) above, so we will refer to that description and omit the explanation here. The specific examples described as preferred examples in section (2-2-1. Polyester Resins) above are also preferred examples in this section (3-1-1-2. Polyester Resins).

[0158] Furthermore, aspects relating to polyester resins other than specific examples of polyester resins may be the same as those described in section (1-1-1. Recycled Polyester Resins) above, so that description will be referenced and the explanation will be omitted here. In particular, aspects other than recycling among those described in section (1-1-1. Recycled Polyester Resins) above can be considered aspects relating to polyester resins and may be referenced as appropriate. The aspects described as preferred in section (1-1-1. Recycled Polyester Resins) above may also be preferred in section (3-1-1-2. Polyester Resins).

[0159] The polyester resin preferably comprises the following (i), (ii), and / or (iii): (i) Polyester resin compositions and / or molded articles that have been commercialized as a polyester resin composition and / or molded article, and have been used and / or discarded, (ii) Waste polyester resin compositions and / or waste molded articles discharged during the manufacturing process of polyester resin compositions and / or molded articles, (iii) A polyester resin obtained by recycling the above (i) and (ii).

[0160] Examples of (i) above include crushed material (such as flakes) obtained by recovering, washing, and crushing used and / or discarded polyester resin compositions and / or molded articles.

[0161] Examples of (iii) include polyester resin compositions and / or molded articles manufactured by material recycling using (i) and / or (ii) as raw materials.

[0162] When the polyester resin includes the aforementioned polyester resin, one embodiment of the present invention can significantly reduce the amount of plastic waste generated and the amount of plastic used in its manufacture. As a result, one embodiment of the present invention can contribute to achieving Sustainable Development Goals (SDGs), such as Goal 12, "Ensure sustainable consumption and production patterns."

[0163] On the other hand, polyester resins that have never been commercialized may also be referred to as "virgin polyester resins" in this specification. In one embodiment of the present invention, the polyester resin used may also include a mixture obtained by mixing the "virgin polyester resin" with the above-mentioned (i), (ii) and / or (iii).

[0164] Conventionally, when recycling (i) and (ii) above, the resulting melt viscosity tends to decrease due to moisture and / or heating during the recycling process. Furthermore, the polyester resin (iii) above may itself be a resin with already reduced melt viscosity. For this reason, conventionally, recycled polyester resins have tended to have limited reuse applications due to their low melt viscosity.

[0165] According to a method for producing a recycled polyester resin composition according to one embodiment of the present invention, in step I, by mixing the whitening inhibitor with the polyester resin, pellets can be prepared in which the melt viscosity is increased and whitening is reduced when the obtained recycled polyester resin composition is molded. Then, by performing SSP in step II using these pellets, the time required to increase the melt viscosity to a target value can be shortened, thereby reducing environmental impact and production costs, and enabling the production of a recycled polyester resin with high melt viscosity.

[0166] Therefore, one embodiment of the present invention has the advantage of greatly expanding the applications of recycled polyester resins, and in particular, of greatly contributing to their development in applications requiring strength and high transparency (for example, alcoholic beverage bottles, beverage bottles, etc.).

[0167] (3-1-1-3. Pellet preparation) In step I, a whitening inhibitor for polyester resins and a polyester resin are melt-kneaded together to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin.

[0168] In the pellets obtained in step I, the content of the whitening inhibitor is not particularly limited, but it is preferably 0.1% to 10.0% by weight of 100% by weight of the pellets. The lower limit of the content is more preferably 0.2% by weight or more. The upper limit of the content may be 8.0% by weight or less, 6.0% by weight or less, or 4.0% by weight or less. If the content of the whitening inhibitor in the pellets is within the above range, there is an advantage in that a good balance is achieved between improving melt viscosity and inhibiting whitening.

[0169] In preparing the pellets, a masterbatch may be used that preferably contains 10.0% to 90.0% by weight of a whitening inhibitor in 100% by weight of the polyester resin composition. When using such a masterbatch, the lower limit of the whitening inhibitor content in the masterbatch is more preferably 20.0% by weight or more in 100% by weight of the polyester resin composition. The upper limit of the content may be 80.0% by weight or less. If the whitening inhibitor content in the masterbatch is within the above range, there is an advantage that the dispersibility of the whitening inhibitor in the polyester resin will be good.

[0170] The method for manufacturing the masterbatch is not particularly limited and can include, for example, a melt-kneading method or a dry-blending method, but the melt-kneading method is particularly preferred.

[0171] In step I, resins other than polyester resins may be further included. Specific examples of resins other than polyester resins are the same as those described in section (1-1-3. Other Resins) above, so we will refer to that description and omit further explanation here.

[0172] The content of resins other than polyester resin in the pellets obtained in step I is not particularly limited, but for example, it may be 0 to 60 parts by weight per 100 parts by weight of polyester resin. The upper limit of the content may be any of the following: 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.

[0173] In process I, other additives may be added. Specific examples of other additives are the same as those described in section (1-1-4. Other Additives) above, so we will refer to that description and omit further explanation here.

[0174] In step I, the method of melt-kneading the whitening inhibitor and the polyester resin is not particularly limited, and a general method for manufacturing resin compositions can be applied. For example, a polyester resin composition can be obtained by mixing the polyester resin and the whitening inhibitor using a Henschel mixer or a tumbler mixer, and then melt-kneading the resulting mixture. A kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a pressure kneader, or a mixing roll can be used for this melt-kneading. Pellets can be produced by such melt-kneading.

[0175] The higher the melt viscosity (IV value) of the pellets, the shorter the time required to raise the melt viscosity of the recycled polyester resin composition to the target value in step II of the SSP process. Furthermore, the whitening inhibitor provides pellets with a higher melt viscosity (IV value) compared to cases where the whitening inhibitor is not present, and / or cases where a conventional viscosity modifier is present. The method for measuring the melt viscosity (IV value) of the resin composition will be described in detail in the following examples.

[0176] Furthermore, the smaller the MFR of the pellets, the stronger the molded article obtained by performing SSP using those pellets. In other words, the whitening inhibitor can provide a recycled polyester resin composition with a lower MFR compared to a case without the whitening inhibitor and / or a case with a conventional viscosity modifier. The method for measuring the MFR of the resin composition will be described in detail in the following examples.

[0177] (3-1-2. Process II) Step II is a step in which solid-phase polymerization is carried out using the pellets prepared in Step I. The method of solid-phase polymerization is not particularly limited, and a reactor and reaction conditions suitable for solid-phase polymerization can be appropriately selected.

[0178] Step II may include, for example, a crystallization step of drying and crystallizing the pellets, a heating step of further heating the crystallized pellets, and a polymerization step of carrying out solid-phase polymerization.

[0179] The crystallization process involves drying and crystallizing the pellets by heating them to 120°C to 150°C under a predetermined pressure. The order of drying and crystallization is not particularly limited; either can be performed first, or both can be performed simultaneously. Furthermore, even when drying and crystallization are performed simultaneously, the entire drying process and the entire crystallization process can be performed simultaneously, or one can be started and / or finished first. The time required for drying and crystallization is also not particularly limited, for example, 1.0 hour to 5.0 hours.

[0180] The heating step is a process of further heating the crystallized pellets. The heating is preferably carried out under a predetermined pressure, for example. Furthermore, it is preferable to heat the pellets to a temperature of, for example, 150°C to 230°C. The time from the start to the end of the heating is not particularly limited, but can be, for example, 1.0 hour to 5.0 hours. Gas may be removed during the heating step.

[0181] Solid-phase polymerization is preferably carried out under a predetermined pressure under an inert gas such as nitrogen gas. Solid-phase polymerization is usually preferably carried out at a temperature in the range of 200°C to 250°C, and more preferably at a temperature in the range of 220°C to 240°C.

[0182] Step II may further include a preheating step of preheating the pellets before the crystallization step.

[0183] In the recycled polyester resin composition obtained by the method for producing a recycled polyester resin composition according to one embodiment of the present invention, the content of the whitening inhibitor is not particularly limited, but is preferably 0.1% to 10.0% by weight of 100% by weight of the recycled polyester resin composition. The lower limit is more preferably 0.2% by weight or more. The upper limit may be 8.0% by weight or less, 6.0% by weight or less, or 4.0% by weight or less. If the content of the whitening inhibitor in the pellets is within the above range, there is an advantage that a good balance is achieved between improved melt viscosity and whitening inhibition.

[0184] The higher the melt viscosity (IV value) of the recycled polyester resin composition, the more powerful the molded article can be provided by that recycled polyester resin composition.

[0185] Furthermore, the smaller the MFR of the recycled polyester resin composition, the stronger the molded article it can provide. The MFR of the recycled polyester resin composition is preferably 3.7 to 30.0, more preferably 5.0 to 25.0, and even more preferably 10.0 to 20.0.

[0186] [3-2. Method for manufacturing molded articles] A method for manufacturing a molded article according to one embodiment of the present invention includes a step of molding a recycled polyester resin composition obtained by the method described in the section [3-1. Method for manufacturing a recycled polyester resin composition] above.

[0187] The method for manufacturing a molded article according to one embodiment of the present invention has the advantage of being able to manufacture a molded article that has excellent strength and reduced whitening, because it has the above configuration.

[0188] The molding method is not particularly limited, and may be the same as the manufacturing method described in section [1-2. Method for Manufacturing a Molded Article] above. Therefore, the description will be omitted here, referring to the description in section [1-2. Method for Manufacturing a Molded Article] above. In one embodiment of the present invention, the molding step is preferably a blow molding step.

[0189] Since the blow molding method has already been explained in section [1-2. Method for Manufacturing Molded Articles] above, we will refer to that description and omit the explanation here.

[0190] [3-3. Physical properties of molded articles] The degree of whitening of a molded article obtained by a method for manufacturing a molded article according to one embodiment of the present invention can be evaluated by the difference in L value (ΔL) before and after tensile testing of a film (molded article) obtained by molding a recycled polyester resin composition into a film. Specifically, a recycled polyester resin composition is molded into a film, and a tensile test is performed on the obtained film (molded article). The smaller the difference in L value (ΔL) before and after tensile testing, the more the recycled polyester resin composition can provide a molded article with reduced whitening. For example, in blow molding of a resin composition or injection-molded article, the resin composition or injection-molded article is molded while being stretched. The stretching of the film (molded article) in the tensile test can be said to mimic the stretching of the resin composition or injection-molded article during blow molding. Therefore, the smaller the ΔL of the film (molded article), the less whitening is found in the blow-molded article (e.g., a bottle-shaped molded article) obtained by blow molding. The film (molded article) according to one embodiment of the present invention has the advantage of having a smaller ΔL compared to a film (molded article) obtained from a conventional recycled polyester resin composition containing a viscosity modifier. In other words, the whitening inhibitor and recycled polyester resin composition have the advantage of providing a film (molded article) with a smaller ΔL compared to conventional resin compositions containing viscosity modifiers.

[0191] Since ΔL is the same as that described in section [1-3. Physical Properties of Molded Articles] above, we will refer to that description and omit the explanation here. The preferred numerical range for ΔL described in section [1-3. Physical Properties of Molded Articles] above can also be said to be a preferred numerical range for ΔL in this section [3-3. Physical Properties of Molded Articles].

[0192] The haze, total light transmittance (TT), and tensile strength of the molded article obtained by the manufacturing method of the molded article according to one embodiment of the present invention are the same as those described in the section [1-3. Physical Properties of the Molded Article] above, so we will refer to that description and omit the explanation here. The preferred numerical ranges for the haze, total light transmittance (TT), and tensile strength of the molded article described in the section [1-3. Physical Properties of the Molded Article] above can also be said to be preferred numerical ranges for the haze, total light transmittance (TT), and tensile strength of the molded article in this section [3-3. Physical Properties of the Molded Article].

[0193] The shape of the molded article according to one embodiment of the present invention is not particularly limited. The shape of the molded article according to one embodiment of the present invention may be, for example, any of the shapes described in the section [1-4. Shape of the molded article] above. Therefore, the description in the section [1-4. Shape of the molded article] above can be appropriately referred to regarding the shape of the molded article according to one embodiment of the present invention. The embodiments described as preferred embodiments in the section [1-4. Shape of the molded article] above are also preferred embodiments in this section (2-3-3. Shape of the molded article).

[0194] [4. Method for manufacturing molded articles] A method for producing a molded article according to one embodiment of the present invention includes the steps of preparing a recycled polyester resin composition and molding the recycled polyester resin composition, wherein the step of preparing the recycled polyester resin composition includes the steps of melt-kneading a whitening inhibitor for polyester resins and a polyester resin to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin, and carrying out solid-phase polymerization using the pellets, wherein the whitening inhibitor for polyester resins is (a) 10 by weight of epoxy group-containing monomers % The present invention comprises a polymer (A) obtained by polymerizing a monomer mixture (A) containing (b) 40% to 90% by weight of an epoxy group-free monomer, and (b) 60% by weight of an epoxy group-free monomer.

[0195] A method for manufacturing a molded article according to one embodiment of the present invention has the advantage of being able to provide a molded article that is excellent in strength and has reduced whitening, because it has the above configuration.

[0196] (4-1. Recycled polyester resin composition) The recycled polyester resin composition used in the method for manufacturing a molded article according to one embodiment of the present invention may be a resin composition containing a recycled polyester resin, and may be, for example, the resin composition described in the section [1-1. Resin Composition] above. Furthermore, the recycled polyester resin composition used in the method for manufacturing a molded article according to one embodiment of the present invention may be a recycled polyester resin composition obtained by the manufacturing method described in the section [3. Method for Manufacturing a Recycled Polyester Resin Composition] above. Therefore, for specific embodiments of the recycled polyester resin composition used in the method for manufacturing a molded article according to one embodiment of the present invention, the descriptions in the section [1-1. Resin Composition] above and the section [3. Method for Manufacturing a Recycled Polyester Resin Composition] above can be appropriately referenced. The embodiments described as preferred embodiments in the section [1-1. Resin Composition] above and the section [3. Method for Manufacturing a Recycled Polyester Resin Composition] above may also be preferred embodiments in this section (4-1. Recycled Polyester Resin Composition).

[0197] (4-2. Whitening inhibitors) The whitening inhibitor used in the method for manufacturing a molded article according to one embodiment of the present invention may be (i) a whitening inhibitor as described in section (1-1-2. Whitening Inhibitor), (ii) a whitening inhibitor as described in section [2. Whitening Inhibitor], or (iii) a whitening inhibitor as described in section (3-1-1-1. Whitening Inhibitor). Therefore, for specific embodiments of the whitening inhibitor used in the method for manufacturing a molded article according to one embodiment of the present invention, the descriptions in section (1-1-2. Whitening Inhibitor), section [2. Whitening Inhibitor], and section (3-1-1-1. Whitening Inhibitor) can be appropriately referenced. Embodiments described as preferred embodiments in section (1-1-2. Whitening Inhibitor), section [2. Whitening Inhibitor], and section (3-1-1-1. Whitening Inhibitor) may also be preferred embodiments in section (4-2. Whitening Inhibitor).

[0198] (4-3. Steps for preparing recycled polyester resin compositions) A method for manufacturing a molded article according to one embodiment of the present invention includes a step of preparing a recycled polyester resin composition. The step of preparing a recycled polyester resin composition may include, for example, the method for manufacturing a recycled polyester resin composition according to one embodiment of the present invention as described in section [3. Method for manufacturing a recycled polyester resin composition] as one step. Therefore, for specific embodiments of the step for preparing a recycled polyester resin composition in the method for manufacturing a molded article according to one embodiment of the present invention, the description in section [3. Method for manufacturing a recycled polyester resin composition] can be appropriately referenced. Embodiments described as preferred embodiments in section [3. Method for manufacturing a recycled polyester resin composition] may also be preferred embodiments in this section (4-2. Step for preparing a recycled polyester resin composition).

[0199] The process for preparing a recycled polyester resin composition includes the steps of melt-kneading a whitening inhibitor for polyester resins and a polyester resin to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin, and carrying out solid-phase polymerization using the pellets.

[0200] The step of "melt-kneading a whitening inhibitor for polyester resins and a polyester resin to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin" may be, for example, step I as described in section (3-1-1. Step I). Therefore, for specific embodiments of the step of "melt-kneading a whitening inhibitor for polyester resins and a polyester resin to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin" in the method for manufacturing a molded article according to one embodiment of the present invention, the description in section (3-1-1. Step I) can be appropriately referenced. The embodiments described as preferred embodiments in section (3-1-1. Step I) may also be preferred embodiments in the step of "melt-kneading a whitening inhibitor for polyester resins and a polyester resin to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin" in the method for manufacturing a molded article according to one embodiment of the present invention.

[0201] The "step of carrying out solid-phase polymerization using the pellets" may be, for example, step II as described in section (3-1-2. Step II) above. Therefore, the description in section (3-1-2. Step II) above can be appropriately referenced to provide specific embodiments of the "step of carrying out solid-phase polymerization using the pellets" in the method for manufacturing a molded article according to one embodiment of the present invention. The embodiments described as preferred embodiments in section (3-1-2. Step II) above may also be preferred embodiments of the "step of carrying out solid-phase polymerization using the pellets" in the method for manufacturing a molded article according to one embodiment of the present invention.

[0202] (4-4. Process for molding recycled polyester resin composition) In the method for manufacturing a molded article according to one embodiment of the present invention, the method for molding the recycled polyester resin composition is not particularly limited. In the method for manufacturing a molded article according to one embodiment of the present invention, the method for molding the recycled polyester resin composition, in other words, the method for manufacturing the molded article, can be the manufacturing method described in [1-2. Method for Manufacturing a Molded Article] above. Therefore, the description in [1-2. Method for Manufacturing a Molded Article] above can be appropriately referenced to provide specific details regarding the "step of molding the recycled polyester resin composition" in the method for manufacturing a molded article according to one embodiment of the present invention. The embodiments described as preferred embodiments in [1-2. Method for Manufacturing a Molded Article] above may also be preferred embodiments in the "step of molding the recycled polyester resin composition" in the method for manufacturing a molded article according to one embodiment of the present invention.

[0203] [5.Applications] (i) For example, a whitening inhibitor for polyester resins according to one embodiment of the present invention as described in the section [2. Whitening Inhibitors] above, (ii) For example, a polyester resin composition according to one embodiment of the present invention as described in the section [2. Whitening Inhibitors] above, (iii) A recycled polyester resin composition obtained by one embodiment of the present invention, obtained by the manufacturing method described in the section [3. Method for Manufacturing Recycled Polyester Resin Compositions] above, and (iv) A molded article according to one embodiment of the present invention, obtained by the manufacturing method described in the section [1. Molded Articles] and / or the section [2. Whitening Inhibitors] and / or the section [3. Method for Manufacturing Recycled Polyester Resin Compositions] above, is preferably used in the following applications, but is not particularly limited: cylinder head cover, engine cover, intake manifold, radiator tank, oil pan, accelerator pedal, etc. Examples of applications include automotive applications such as ventilators, 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, fiber optic cable coatings, power tools, and wire binding materials; mechanical applications such as hydraulic and pneumatic connectors and tubes, bearings, covers and housings, pressure-resistant hoses, and cable ties; building materials such as curtain rail components, 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 containers such as shrink wrap film, food packaging film, alcoholic beverage bottles, beverage bottles, and pesticide bottles; and medical applications such as toothbrushes, chair legs and armrests, and sutures. However, the applications are not particularly limited. The molded body is preferably a bottle.

[0204] One embodiment of the present invention may have the following configuration.

[0205] [1] A molded article obtained by molding a resin composition containing recycled polyester resin, wherein the haze of the solution of the molded article is 1.50% or more, and the haze of the molded article is 7.5 %The following is the molded body: Here, the haze of the solution of the molded body is a value measured by performing (1) to (2) below in order; (1) Dissolve the resin composition in hexafluoro-2-propanol to obtain a solution in which the concentration of the resin composition is 0.05 g / mL; (2) Using a haze meter zeroed with hexafluoro-2-propanol, measure the haze of the resulting molded product solution; The haze of the molded body is the value obtained by measuring it using a haze meter.

[0206] [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: Here, the MFR is a value obtained by measurement in accordance with JIS K 7210-1 under the conditions of drying at 130°C for 8 hours, temperature at 270°C, and load at 2.16 kg.

[0207] [3] The molded body according to [1] or [2], wherein the total light transmittance (TT) of the molded body is 80.0% or more: Here, the total light transmittance (TT) of the molded body is the value obtained by measuring it using a haze meter.

[0208] [4] The molded article according to any one of [1] to [3], wherein the recycled polyester resin includes 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].

[0209] [5] The molded body is bottle-shaped, as described in any one of [1] to [4].

[0210] [6] The resin composition further comprises a whitening inhibitor for polyester resins, wherein the whitening inhibitor for polyester resins comprises a polymer (A) obtained by polymerizing a monomer mixture (A) comprising (a) 10% to 60% by weight of epoxy group-containing monomers and (b) 40% to 90% by weight of epoxy group-free monomers, as described in any one of [1] to [5].

[0211] [7] The molded article according to [6], wherein the monomer mixture (A) further comprises (c) 0% to 10% by weight of vinyl monomers other than components (a) and (b) that are copolymerizable with components (a) and (b).

[0212] [8] The molded article according to [6] or [7], wherein the epoxy group-free monomer (b) is an epoxy group-free alkyl methacrylate.

[0213] [9] The molded article according to any one of [6] to [8], wherein the number average molecular weight of the polymer (A) is 2,000 to 6,000.

[0214]

[10] The polymer (A) has an average of 2 to 8 reactive functional groups per molecule of polymer (A), the molded article according to any one of [6] to [9].

[0215]

[11] The molded article according to any one of [6] to

[10] , wherein the whitening inhibitor for polyester resins does not contain the polymer (A) having a molecular weight of 1000 or less, or contains the polymer (A) having a molecular weight of 1000 or less in an amount of 4.00% by weight or less of the polymer (A) in 100% by weight of the whitening inhibitor for polyester resins.

[0216]

[12] The whitening inhibitor for polyester resins further comprises a polymer (B), The composite comprising polymer (A) and polymer (B) has a core-shell structure in which polymer (A) forms the core and polymer (B) forms the shell. The molded article according to any one of [6] to

[11] , wherein the ratio of the weight of polymer (A) to the weight of polymer (B) in the composite (weight of polymer (A) / weight of polymer (B)) is 20 / 80 to 80 / 20.

[0217]

[13] In the composite, The number-average molecular weight of polymer (A) is 2,000 to 5,000. The molded article according to

[12] , wherein the number average molecular weight of the polymer (B) is 3,000 to 6,000.

[0218]

[14] The molded article according to any one of [6] to

[13] , wherein the polymer (A) is a polymer obtained by emulsion polymerization.

[0219]

[15] (a) 10% to 60% by weight of epoxy group-containing monomer, and (b) A whitening inhibitor for polyester resins comprising a polymer (A) obtained by polymerizing a monomer mixture (A) containing 40% to 90% by weight of epoxy group-free monomers.

[0220]

[16] A step of preparing a recycled polyester resin composition, The process includes molding the recycled polyester resin composition, The step of preparing the recycled polyester resin composition is as follows: A step of melt-kneading a whitening inhibitor for polyester resins and a polyester resin to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin, The process includes a step of carrying out solid-phase polymerization using the pellets, The aforementioned whitening inhibitor for polyester resins is (a) 10 wts epoxy group-containing monomer % ~60% by weight, (b) A method for producing a molded article, comprising polymerizing a monomer mixture (A) containing 40% to 90% by weight of epoxy group-free monomers, the polymer comprising a polymer (A).

[0221]

[17] The method for producing a molded article according to

[16] , wherein the recycled polyester resin composition has an MFR of 3.7 to 30.0.

[0222] One embodiment of the present invention may have the following configuration.

[0223] [A1] A whitening inhibitor for polyester resins comprising a polymer (A) obtained by polymerizing a monomer mixture (A) containing (a) 10% to 60% by weight of an epoxy group-containing monomer and (b) 40% to 90% by weight of an epoxy group-free monomer.

[0224] [A2] The monomer mixture (A) further comprises (c) 0% to 10% by weight of a vinyl monomer other than (a) and (b) that is copolymerizable with (a) and (b), the whitening inhibitor for polyester resins according to [A1].

[0225] [A3] The (b) epoxy group-free monomer is an epoxy group-free alkyl methacrylate, as described in [A1] or [A2], which is a whitening inhibitor for polyester resins.

[0226] [A4] The number average molecular weight of the polymer (A) is 2,000 to 6,000, a whitening inhibitor for polyester resins according to any one of [A1] to [A3].

[0227] [A5] The polymer (A) has an average of 2 to 8 reactive functional groups per molecule of polymer (A), the whitening inhibitor for polyester resins according to any one of [A1] to [A4].

[0228] [A6] The whitening inhibitor for polyester resins according to any one of [A1] to [A5], wherein the polymer (A) having a number average molecular weight of 1000 or less is not included, or the polymer (A) having a number average molecular weight of 1000 or less is included in an amount of 4.00% by weight or less of the polymer (A) in 100% by weight of the whitening inhibitor for polyester resins.

[0229] [A7] The whitening inhibitor for polyester resins according to any one of [A1] to [A6], wherein the composite comprising polymer (A) and polymer (B) has a core-shell structure in which polymer (A) forms a core and polymer (B) forms a shell, and the ratio of the weight of polymer (A) to the weight of polymer (B) in the composite (weight of polymer (A) / weight of polymer (B)) is 20 / 80 to 80 / 20.

[0230] [A8] The whitening inhibitor for polyester resins according to [A7], wherein in the composite, the number average molecular weight of polymer (A) is 2,000 to 5,000, and the number average molecular weight of polymer (B) is 3,000 to 6,000.

[0231] A polyester resin composition comprising a polyester resin and a polyester resin, wherein the whitening inhibitor for polyester resins described in any one of [A9], [A1], to [A8].

[0232] [A10] The polyester resin composition according to [A9], wherein the polyester resin composition contains 0.1% to 10.0% by weight of the whitening inhibitor for polyester resins in 100% by weight of the polyester resin composition.

[0233] [A11] The polyester resin composition according to [A9], wherein the polyester resin composition contains 10.0% to 90.0% by weight of the polyester resin whitening inhibitor in 100% by weight of the polyester resin composition, and is a masterbatch.

[0234] [A12] A polyester resin composition according to any one of [A9] to [A11], comprising recycled polyester resin.

[0235] [A13] The polyester resin composition according to any one of [A9] to [A12], wherein the polyester resin comprises one or more selected from the group consisting of polycarbonate / polyethylene terephthalate, polyethylene terephthalate / glycol-modified polyethylene terephthalate, and polyethylene terephthalate / copolymerized polyethylene terephthalate.

[0236] A molded article obtained by molding a polyester resin composition described in any one of [A14], [A9], to [A13].

[0237] A molded article obtained by blow molding a polyester resin composition described in any one of [A15], [A9], to [A13].

[0238] One embodiment of the present invention may have the following configuration.

[0239] [B1] The process includes the steps of melt-kneading a whitening inhibitor for polyester resins and a polyester resin to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin, and carrying out solid-phase polymerization using the pellets. The aforementioned whitening inhibitor for polyester resins is (a) 10 wts epoxy group-containing monomer % ~60% by weight, (b) A method for producing a recycled polyester resin composition comprising a polymer (A) obtained by polymerizing a monomer mixture (A) containing 40% to 90% by weight of epoxy group-free monomers.

[0240] [B2] The method for producing a recycled polyester resin composition according to [B1], wherein the monomer mixture (A) further comprises (c) 0% to 10% by weight of vinyl monomers other than (a) and (b) that are copolymerizable with (a) and (b).

[0241] [B3] The method for producing epoxy group-free monomers according to (b) or [B2], wherein the epoxy group-free monomer is an epoxy group-free alkyl methacrylate.

[0242] [B4] The manufacturing method according to any one of [B1] to [B3], wherein the number average molecular weight of the polymer (A) is 2,000 to 6,000.

[0243] [B5] The polymer (A) has an average of 2 to 15 reactive functional groups per molecule of polymer (A), the manufacturing method according to any one of [B1] to [B4].

[0244] [B6] The manufacturing method according to any one of [B1] to [B5], wherein the whitening inhibitor for polyester resins does not contain the polymer (A) having a number average molecular weight of 1000 or less, or contains the polymer (A) having a number average molecular weight of 1000 or less in an amount of 4.00% by weight or less of the polymer (A) in 100% by weight of the whitening inhibitor for polyester resins.

[0245] [B7] The whitening inhibitor for polyester resins further comprises a polymer (B), The composite comprising polymer (A) and polymer (B) has a core-shell structure in which polymer (A) forms the core and polymer (B) forms the shell. The manufacturing method according to any one of [B1] to [B6], wherein the ratio of the weight of polymer (A) to the weight of polymer (B) in the composite (weight of polymer (A) / weight of polymer (B)) is 20 / 80 to 80 / 20.

[0246] [B8] In the composite, The number-average molecular weight of polymer (A) is 2,000 to 5,000. The method for producing polymer (B) described in [B7], wherein the number average molecular weight of polymer (B) is 3,000 to 6,000.

[0247] [B9] The manufacturing method according to any one of [B1] to [B8], wherein the whitening inhibitor for polyester resins is contained in 0.1% to 10.0% by weight of 100% by weight of the recycled polyester resin composition.

[0248] [B10] The recycled polyester resin composition has an MFR of 3.7 to 30.0, manufactured according to any one of [B1] to [B9].

[0249] [B11] The manufacturing method according to any one of [B1] to [B10], wherein the polyester resin comprises one or more selected from the group consisting of polycarbonate / polyethylene terephthalate, polyethylene terephthalate / glycol-modified polyethylene terephthalate, and polyethylene terephthalate / copolymerized polyethylene terephthalate.

[0250] A method for producing a molded article, comprising the step of molding the recycled polyester resin composition obtained by the manufacturing method described in any of [B12], [B1], to [B11].

[0251] [B13] The manufacturing method according to [B12], wherein the molding step is a blow molding step.

[0252] One embodiment of the present invention may have the following configuration.

[0253] [C1] A molded article obtained by molding a resin composition containing recycled polyester resin, The haze of the solution of the molded article is 1.50% or more. The haze of the molded body is 7.5 % The following is the molded body: Here, the haze of the solution of the molded body is a value measured by performing (1) to (2) below in order; (1) Dissolve the resin composition in hexafluoro-2-propanol to obtain a solution in which the concentration of the resin composition is 0.05 g / mL; (2) Using a haze meter zeroed with hexafluoro-2-propanol, measure the haze of the resulting molded product solution; The haze of the molded body is the value obtained by measuring it using a haze meter.

[0254] The molded article according to [C1], wherein the melt flow rate (MFR) of the resin composition is 3.7 g / 10 min to 30.0 g / 10 min: Here, the MFR is a value obtained by measuring 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.

[0255] The molded article according to [C1] or [C2], wherein the total light transmittance (TT) of the molded article is 80% or more: Here, the total light transmittance (TT) of the molded article is a value obtained by measuring using a haze meter.

[0256] The molded article according to any one of [C1] to [C3], wherein the recycled polyester-based resin contains 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].

[0257] The molded article according to any one of [C1] to [C4], wherein the molded article has a bottle shape.

Examples

[0258] The present invention will be described more specifically according to the following examples and comparative examples, but the present invention is not construed as being limited thereto, and examples obtained by appropriately combining the technical means disclosed in each example are also included in the scope of the present invention.

[0259] [Measurement methods 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 obtained by the method of calculating the volume average particle size.

[0260] 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.

[0261] 3.Number average molecular weight The number-average molecular weights of polymers (A) and (B) were calculated by GPC measurement. A GPC instrument manufactured by Tosoh Corporation was used. The analysis conditions were as follows: Column 1 (low molecular weight column) Column 1: TSKgel SuperH5000 Second column: TSKgel SuperH4000 Third column: TSKgel SuperH3000 Column 4: TSKgel SuperH2000 Column 2 (polymer column) Column 1: TSKgel SuperHZM-H Second column: TSKgel SuperHZM-H Injection method: Syringe measurement Loop volume: 100 μL Reserve aspiration volume: 150 μL Air volume: 3.5 μL Automatic washing capacity: 1.0 mL Syringe speed Sampling rate: 10 μL / s Washing speed: 100 μL / s Measuring speed: 5μL / s Sample flow rate: 0.350 mL / min Reference flow ratio: 1x Flow rate increase / decrease control: Disabled Flow rate increase rate: 0.35 mL / min Flow rate reduction rate: 0.35mL / min Pressure limit Column 1 Sample pressure limit: 12.0 MPa Sample pressure lower limit: 0.2 MPa Reference pressure limit: 25.0 MPa Reference pressure lower limit: 0.2 MPa Column 2 Sample pressure limit: 25.0 MPa Lower limit of sample pressure: 0.2 MPa Upper limit of reference pressure: 12.0 MPa Lower limit of reference pressure: 0.2 MPa Flow rate Column 1 Sample flow rate: 0.600 mL / min Reference flow rate ratio: 1 / 2 Column 2 Sample flow rate: 0.350 mL / min Reference flow rate ratio: equal multiples Flow rate increase / decrease control: invalid Flow rate increase rate: 0.35 mL / min / min Flow rate decrease rate: 0.35 mL / min / min Pressure limit Column 1 Upper limit of sample pressure: 12.0 MPa Lower limit of sample pressure: 0.2 MPa Upper limit of reference pressure: 25.0 MPa Lower limit of reference pressure: 0.2 MPa Peak detection conditions RI Detection sensitivity (front side): 3.000 mV / min Detection sensitivity (rear side): 3.000 mV / min Base determination value: 1.000 mV / min Exclusion area: 10.000 mVs Exclusion height: 0.000 mV Exclusion half-width: 0.000 s UV / EXT Detection sensitivity (front side): 3.000 mV / min Detection sensitivity (rear side): 3.000 mV / min Base determination value: 1.000 mV / min Exclusion area: 10.000 mVs Exclusion height: 0.000 mV Exclusion half-width: 0.000 s Polystyrene was used as the reference material. Specifically, GPC was performed using polystyrene with a known number-average molecular weight under the conditions described above to obtain a calibration curve. Subsequently, GPC was performed on the samples (polymer (A) and polymer (B)) under the conditions described above, and the number-average molecular weight of each sample was calculated from the calibration curve.

[0262] 4. Melt viscosity (IV value) of the resin composition (recycled polyester resin composition or polyester resin composition) The IV value of the resin composition was measured in accordance with JIS K 7367-5.

[0263] 5. Melt flow rate (MFR) of polyester resins, pellets, and resin compositions (recycled polyester resin compositions or polyester resin compositions) The melt flow rate (MFR) of polyester resins, pellets, and resin compositions was measured in accordance with JIS K 7210-1 under the conditions of drying at 130°C for 8 hours, temperature at 270°C, and load of 2.16 kg.

[0264] 6. ΔL of the film (molded body) The ΔL of the resin compositions of each example, comparative example, and reference example was measured by the following method: (1) A pellet of the resin composition was heated to 270°C using an extruder equipped with a T-die (Toyo Seiki Co., Ltd., LABO PLASTOMILL) to form a film with a thickness of 200 μm; (2) The obtained film was punched out into a dumbbell shape No. 2 according to JIS K 6251 to obtain a dumbbell; (3) The L value of the obtained dumbbell was measured using a colorimeter (Nippon Denshoku Industries Co., Ltd., Colormeter ZE6000), and the obtained value was taken as the L value before tensile strength; (4) The dumbbell was subjected to JIS K In accordance with 7113, the dumbbell was stretched to 8.5 times its original size using a tensile testing machine (Shimadzu AG-2000E) at 95°C and 1000 mm / min; (5) The L value of the stretched dumbbell was measured using the colorimeter, and the obtained value was taken as the L value after stretching; (6) The L value before stretching was subtracted from the L value after stretching, and the resulting difference was taken as the ΔL of the film (molded body).

[0265] 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 content concentration of 0.05 g / mL; (2) The haze and total light transmittance of the obtained solution of the molded body were measured using a haze meter (NDH4000, manufactured by Nippon Denshoku Industries Co., Ltd.) zeroed with HFIP.

[0266] 8. L value of the molded body The L value of the molded body was measured using a colorimeter (Nippon Denshoku Industries, Color Meter ZE6000).

[0267] 9. Haze on the molded body The haze of the molded product was measured using a haze meter (NDH4000, manufactured by Nippon Denshoku Industries).

[0268] 10. Total light transmittance (TT) of the molded product The total light transmittance (TT) of the molded product was measured using a haze meter (NDH4000, manufactured by Nippon Denshoku Industries).

[0269] 11. Strength The molded body was used as a sample, and measurements were taken using a compression tester (AND Corporation, MCT-1150) at a descent speed of 50 mm / min.

[0270] 12. Wall thickness of the bottle (molded body) The wall thickness of the bottle (molded body) was measured at points located vertically above the bottom of the bottle (molded body) at various distances, using a magnetic thickness gauge (OLYMPUS MAGNA MIKE).

[0271] 13. Powder productivity 2.5g of powder was spread evenly over a 2cm x 5cm area on a stainless steel plate. Next, another stainless steel plate of the same type was placed on top, sandwiching the powder. A 5kg weight was then placed on top, and the plate was heated in a 70°C oven for 2 hours. After natural cooling, the stainless steel plates were positioned vertically, and the weight percentage of the powder remaining attached to the plates was measured. The evaluation criteria are as follows; a higher number indicates superior powder productivity. 2 (Good): Less than 20% by weight 1 (Pass): 20% to 50% by weight 0 (Defective): Greater than 50% by weight.

[0272] [Whitening inhibitor] (Example A1) (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 the reactor. The temperature inside the reactor was raised to 75°C while stirring the mixture, and the mixture was bubbling with nitrogen for 30 minutes.

[0273] Subsequently, monomer mixture (A), consisting of 35 parts by weight of methyl methacrylate (MMA), component (b), 15 parts by weight of glycidyl methacrylate (GMA), component (a), and 2 parts by weight of n-octyl mercaptan, a chain transfer agent, was added to the reactor over 150 minutes. While monomer mixture (A) was being added (for 150 minutes), 0.1 parts by weight of t-butyl hydroperoxide, a polymerization initiator, was added to the reactor over 150 minutes. Eighty minutes after the addition of monomer mixture (A), 0.2 parts by weight of sodium polyoxyethylene lauryl ether phosphate, an anionic surfactant, was added to the reactor all at once. The reaction was then carried out until the polymerization conversion rate reached 90%, and then the reaction was continued for another 30 minutes after the polymerization conversion rate reached 90%. Polymer (A) was obtained by this operation.

[0274] (Production of polymer (B) (production of composites having a core-shell structure)) Next, 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 polymer (A). While monomer mixture (B) was being added, 0.1 parts by weight of t-butyl hydroperoxide, a polymerization initiator, was added to the reactor. During the addition of monomer mixture (B), 0.2 parts by weight of sodium polyoxyethylene lauryl ether phosphate, an anionic surfactant, was added to the reactor as needed. The reaction was then carried out until the polymerization conversion rate reached 98%, and then the reaction was continued for another 30 minutes after the polymerization conversion rate reached 98%. Polymer (B) was obtained by this procedure.

[0275] Ultimately, a latex was obtained containing a composite of polymers (A) and (B) with a particle size of 1100 angstroms. The final polymerization conversion rate was 98%.

[0276] In the composite obtained by the above-described manufacturing method, polymer (A) can be considered to form the core portion, and polymer (B) can be considered to form the shell portion. In other words, the composite can be considered to have a core-shell structure.

[0277] The obtained latex contained two types of number-average molecular weights (Mn): polymer (A) (core component) had a number-average molecular weight of 3,000, and polymer (B) (shell component) had a number-average molecular weight of 4,000. The average number of epoxy groups in polymer (A) (core component) was 5, and the average number of epoxy groups in polymer (B) (shell component) was 6, resulting in an average of 5.5 epoxy groups per polymer molecule.

[0278] To recover the composite particles from the latex as a powder, the obtained latex was rapidly added to a 5% calcium chloride aqueous solution while stirring the solution. The temperature of the mixture was maintained at 70°C by steam. The temperature of the mixture was then raised to 85°C to dehydrate the aggregates of the composite particles. The resulting aggregates were dried to obtain the 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.

[0279] (Example A2) Polymer (A) was produced in the same manner as in Example A1, except that monomer mixture (A) was changed to monomer mixture (A) consisting of 35 parts by weight of MMA, 15 parts by weight of GMA, and 1.5 parts by weight of n-octyl mercaptan. Polymer (B) was not produced in Example A2. In Example A2, latex containing polymer (A) was ultimately obtained. Then, polymer (A) particles were recovered from the latex as powder using the same method as in Example A1, and the obtained powder was used as a whitening inhibitor.

[0280] (Example A3) Polymer (A) was produced using the same method as in Example A1. Polymer (B) was not produced in Example A3. In Example A3, latex containing polymer (A) was ultimately obtained. Then, polymer (A) particles were recovered from the latex as a powder using the same method as in Example A1, and the obtained powder was used as a whitening inhibitor.

[0281] (Example A4) Polymer (A) was produced in the same manner as in Example A1, except that monomer mixture (A) was changed to monomer mixture (A) consisting of 42.5 parts by weight of MMA, 7.5 parts by weight of GMA, and 2 parts by weight of n-octyl mercaptan. Polymer (B) was not produced in Example A4. In Example A4, latex containing polymer (A) was ultimately obtained. Then, polymer (A) particles were recovered from the latex as powder using the same method as in Example A1, and the obtained powder was used as a whitening inhibitor.

[0282] (Comparative Example A1) In Example A1, the same procedure as in Example A1 was carried out, except that (i) 35 parts by weight of MMA in 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 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), to obtain a latex containing the composite. The composite in the obtained latex had a number-average molecular weight of polymer (A) of 9,900 and a number-average molecular weight of polymer (B) of 120,000, with an average of 9 epoxy groups per molecule of polymer (A) and an unknown average of 9 epoxy groups per molecule of polymer (B). Subsequently, a powder of the composite was obtained from the latex in the same manner as in Example A1 and used as a whitening inhibitor.

[0283] Table 1 shows the weight parts of polymer (A) and polymer (B), number-average molecular weight, number of reactive functional groups per molecule, and the amount (weight %) of component (a) in 100% by weight of the polymer or composite for the whitening inhibitors of Examples A1 to A4 and Comparative Example A1. The productivity of the powder was also evaluated. The results are shown in Table 1.

[0284] [Table 1] [Resin composition] (raw materials) • Polyester resin: Virgin polyester resin (Unitika Corporation, MA-8334P). After subjecting it to heat treatment in the following manner, it was used in the production of the resin composition: Only the virgin polyester resin was melt-kneaded at 270°C using a twin-screw extruder (Leistritz, 35 mm, L / D=17), and the molten mixture extruded from the die was cut.

[0285] • Whitening inhibitor: The whitening inhibitors of Examples A1-A4 and Comparative Example A1 were melt-kneaded at 270°C using a twin-screw extruder (LABO PLASTOMILL, Brabender, 19mm, L / D=20, manufactured by Toyo Seiki Co., Ltd.), and the molten mixture extruded from the 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 the resin composition.

[0286] (Examples A5-A8, Comparative Example A2, and Reference Example A) For each of Example A, Comparative Example A, and Reference Example A, the polyester resin and whitening inhibitor listed in Table 2 were subjected to a twin-screw extruder (Leistritz, 35 mm, L / D=17) in the amounts listed in Table 2. These mixtures were melt-kneaded in the extruder at 270°C, and the molten mixture extruded from the die was cut. By this operation, pellets of the resin composition were obtained.

[0287] The melt viscosity (IV value) and MFR were measured for the pellets of the resin compositions obtained in each Example A, Comparative Example A, and Reference Example A, or for the pellets of Reference Example A, using the method described above. Furthermore, the ΔL of the films (molded articles) of the resin compositions obtained in each Example A, Comparative Example A, and Reference Example A was measured using the method described above. These results are shown in Table 2. The amount (weight %) of component (a) when the entire resin composition is considered as 100% by weight is shown in the "(a) component (weight %)" column.

[0288] [Table 2] [Molded body] (raw materials) • Polyester resin: Recycled polyester resin (rPET FG Resins).

[0289] • Whitening inhibitor: The whitening inhibitors of Example A1 and Comparative Example A1 were melt-kneaded at 270°C using a twin-screw extruder (LABO PLASTOMILL, Brabender, 19mm, L / D=20, manufactured by Toyo Seiki Co., Ltd.), and the molten mixture extruded from the die was cut. By this operation, pellets of the whitening inhibitor were obtained. The obtained pellets of the whitening inhibitor were used in the manufacture of molded articles.

[0290] (Examples A9, A10, Comparative Example A3, and Reference Example A2) (Manufacturing of resin compositions) For each of Example A, Comparative Example A, and Reference Example A, the polyester resin and whitening inhibitor listed in Table 3 were subjected to a twin-screw extruder (Leistritz, 35 mm, L / D=17) in the amounts listed in Table 3. These mixtures were melt-kneaded in the extruder at 270°C, and the molten mixture extruded from the die was cut. By this operation, pellets of the resin composition were obtained.

[0291] (Reference example A3) The resin composition of Reference Example A3 was obtained by introducing recycled polyester resin pellets into a batch-type SSP reactor and carrying out solid-phase polymerization at 230°C.

[0292] The melt viscosity (IV value) and MFR were measured and evaluated for the pellets of the resin compositions obtained in each Example A, Comparative Example A, and Reference Example A2, as well as the pellets of Reference Example A3, using the method described above. Furthermore, the ΔL of the films (molded articles) of the resin compositions obtained in each Example A, Comparative Example A, and Reference Example A was measured using the method described above. The results are shown in Table 3.

[0293] [Table 3] (Manufacturing of bottles (molded products)) The resin composition pellets obtained in each of Example A, Comparative Example A, and Reference Example A were injection molded at a molding temperature of 280°C using an injection molding machine (Nissei Plastic Industrial Co., Ltd., FNX-140, screw Φ45) to obtain preform molded bodies. The obtained preform molded bodies were blow molded at a surface temperature of approximately 100°C using a blow molding machine (Frontier Co., Ltd., FXT-1R) to obtain bottle-shaped molded bodies with a volume of 500 ml.

[0294] For each bottle (molded body) obtained in Example A, Comparative Example A, and Reference Example A, the L value, haze, total light transmittance (TT), wall thickness (distance from the bottom), and buckling strength were measured using the method described above. The results are shown in Table 4. In addition, for each bottle (molded body) obtained in Example A and Comparative Example A, the L value of Reference Example A2 (which does not contain a whitening inhibitor) was subtracted from the L value of each Example A and Comparative Example A, and the resulting difference (value) was defined as ΔL for each Example A and Comparative Example A, and is shown in Table 4. Furthermore, the haze of the solution was also measured for each bottle (molded body) obtained in Example A and Reference Example A3.

[0295] [Table 4] [Recycled polyester resin composition] (raw materials) • Polyester resin: Made from recycled PET bottle flakes, which are crushed recycled PET bottles.

[0296] • Whitening inhibitor: The whitening inhibitors of Example A1 and Comparative Example A1 were melt-kneaded at 270°C using a twin-screw extruder (LABO PLASTOMILL, Brabender, 19mm, L / D=20, manufactured by Toyo Seiki Co., Ltd.), and the molten mixture extruded from the die was cut. This operation yielded pellets of the whitening inhibitor. The obtained pellets of the whitening inhibitor were used in Example B and Comparative Example B described below.

[0297] (Examples B1-B4 and Comparative Examples B1-B4) For each Example B and each Comparative Example B, the polyester resin (recycled PET bottle flakes) and whitening inhibitor listed in Table 5 were subjected to a twin-screw extruder (Leistritz, 35 mm, L / D=17) in the amounts listed in Table 5. These mixtures were melt-kneaded in the extruder at 270°C, and the molten mixture extruded from the die was cut. By this operation, pellets of the resin composition were obtained.

[0298] [Table 5] Using the obtained pellets, SSP was performed until the melt viscosity (IV value) reached 0.84 to produce a recycled polyester resin composition.

[0299] Specifically, the pellets were placed in a rotary reactor and the reaction was carried out by stirring while heating. Heating was performed in the following order from (i) to (vii) at the temperatures and times listed in Table 6, and after the reaction, the pellets were removed.

[0300] [Table 6] For each of Example B and Comparative Example B, the melt viscosity (IV value), MFR, and ΔL were measured using the method described above for the recycled PET bottle flakes, the whitening inhibitor for polyester resins, and the pellets containing polyester resins, as well as the recycled polyester resin composition after the SSP process. These measurement results and the SSP process until the IV value reached 0.84 were also measured. reaction The times are shown in Table 5.

[0301] As shown in Table 5, when the whitening inhibitor obtained in Comparative Example A1 was used instead of the whitening inhibitor obtained in Example A1, it was necessary to add approximately 1% by weight of the whitening inhibitor in order to raise the IV value of the pellets above that of the recycled PET bottle flakes. Furthermore, the ΔL of the recycled polyester resin compositions of Examples B1 to B3 obtained using the whitening inhibitor obtained in Example A1 was significantly smaller than the ΔL of the recycled polyester resin compositions of Comparative Examples B2 to B4 obtained using the whitening inhibitor obtained in Comparative Example A1 instead of the whitening inhibitor obtained in Example A1.

[0302] (Manufacturing of bottles (molded products)) The recycled polyester resin composition obtained in Example B1 was injection molded at a molding temperature of 280°C using an injection molding machine (Nissei Plastic Industrial Co., Ltd., FNX-140, screw Φ45) to obtain a preform molded body. The obtained preform molded body was blow molded at a surface temperature of approximately 100°C using a blow molding machine (Frontier Co., Ltd., FXT-1R) to obtain a 500 ml bottle (molded body).

[0303] Furthermore, a bottle (molded article) was obtained using the recycled polyester resin composition obtained in the same manner as in Example B, using the whitening inhibitor obtained in Comparative Example A1 instead of the whitening inhibitor obtained in Example A1, and using the method described above. The bottle (molded article) obtained from the recycled polyester resin composition obtained in Example B1 showed less whitening than the bottle (molded article) obtained from the recycled polyester resin composition obtained in the same manner as in Example B, using the whitening inhibitor obtained in Comparative Example A1 instead of the whitening inhibitor obtained in Example A1. [Industrial applicability]

[0304] According to one embodiment of the present invention, a molded article containing a recycled polyester resin can be provided, which has excellent strength and reduced whitening. Furthermore, according to one embodiment of the present invention, a whitening inhibitor for polyester resins can be provided, which can provide a polyester resin composition that can provide a molded article with excellent strength and reduced whitening. Therefore, one embodiment of the present invention can be suitably used in 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, fiber optic cable coatings, power tools, and wire binding materials; mechanical applications such as hydraulic and pneumatic connectors and tubes, bearings, covers and housings, pressure-resistant hoses, and cable ties; building materials applications such as curtain rail components, 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 containers such as shrink wrap film, food packaging film, 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 made by molding a resin composition containing recycled polyester resin, The haze of the solution of the molded article is 1.50% or more. The haze of the molded body is 7.5% or less. Here, the haze of the solution of the molded body is a value measured by performing (1) to (2) below in order; (1) Dissolve the resin composition in hexafluoro-2-propanol to obtain a solution in which the concentration of the resin composition is 0.05 g / mL; (2) Using a haze meter zeroed with hexafluoro-2-propanol, measure the haze of the resulting molded body solution; The haze of the molded body is the value obtained by measuring it using a haze meter.

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: Here, the MFR is a value obtained by measurement 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.

3. The molded body according to claim 1, wherein the total light transmittance (TT) of the molded body is 80.0% or more: Here, the total light transmittance (TT) of the molded body is the value obtained by measuring it using a haze meter.

4. The molded article according to claim 1, wherein the recycled polyester resin comprises 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].

5. The molded body according to any one of claims 1 to 4, wherein the molded body is bottle-shaped.

6. The aforementioned resin composition further comprises a whitening inhibitor for polyester resins. The molded article according to claim 1, wherein the whitening inhibitor for polyester resins comprises a polymer (A) obtained by polymerizing a monomer mixture (A) containing (a) 10% to 60% by weight of an epoxy group-containing monomer and (b) 40% to 90% by weight of an epoxy group-free monomer.

7. The molded article according to claim 6, wherein the monomer mixture (A) further comprises (c) 0% to 10% by weight of vinyl monomers other than components (a) and (b) that are copolymerizable with components (a) and (b).

8. The molded article according to claim 6 or 7, wherein the epoxy group-free monomer (b) is an epoxy group-free alkyl methacrylate.

9. The molded article according to claim 6 or 7, wherein the number average molecular weight of the polymer (A) is 2,000 to 6,000.

10. The molded article according to claim 6 or 7, wherein the polymer (A) has an average of 2 to 8 reactive functional groups per molecule of polymer (A).

11. The molded article according to claim 6 or 7, wherein the whitening inhibitor for polyester resins does not contain the polymer (A) having a molecular weight of 1000 or less, or contains the polymer (A) having a molecular weight of 1000 or less in an amount of 4.00% by weight or less of the polymer (A) in 100% by weight of the whitening inhibitor for polyester resins.

12. The aforementioned whitening inhibitor for polyester resins further comprises polymer (B), The composite comprising polymer (A) and polymer (B) has a core-shell structure in which polymer (A) forms the core and polymer (B) forms the shell. The molded article according to claim 6 or 7, wherein the ratio of the weight of polymer (A) to the weight of polymer (B) in the composite (weight of polymer (A) / weight of polymer (B)) is 20 / 80 to 80 / 20.

13. In the aforementioned composite, The number-average molecular weight of polymer (A) is 2,000 to 5,000. The molded article according to claim 12, wherein the number average molecular weight of the polymer (B) is 3,000 to 6,000.

14. (a) 10% to 60% by weight of epoxy group-containing monomer, and (b) A whitening inhibitor for polyester resins comprising a polymer (A) obtained by polymerizing a monomer mixture (A) containing 40% to 90% by weight of an epoxy group-free monomer.

15. A step of preparing a recycled polyester resin composition, The process includes molding the recycled polyester resin composition, The step of preparing the recycled polyester resin composition is as follows: A step of melt-kneading a whitening inhibitor for polyester resins and a polyester resin to prepare pellets containing the whitening inhibitor for polyester resins and the polyester resin, The process includes a step of carrying out solid-phase polymerization using the pellets, The aforementioned whitening inhibitor for polyester resins is (a) 10% to 60% by weight of epoxy group-containing monomer, and (b) A method for producing a molded article, comprising polymerizing a monomer mixture (A) containing 40% to 90% by weight of epoxy group-free monomers, the polymer comprising polymerized polymer (A).

16. The method for producing a molded article according to claim 15, wherein the recycled polyester resin composition has an MFR of 3.7 to 30.0.

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