Method for suppressing crystallization of polyester resins

Abstract

To provide a novel method that can suppress the crystallization of polyester resins. [Solution] A method for suppressing crystallization of a polyester resin, comprising a mixing step of mixing a crystalline polyester resin (A) and an amorphous polyester resin (B).

Description

Technical Field

[0001] The present invention relates to a method for suppressing crystallization of polyester resins.

Background Art

[0002] Thermoplastic polyester resins such as polyethylene terephthalate are excellent in transparency, mechanical properties, gas barrier properties, heat resistance, solvent resistance, economy, recyclability, etc. Therefore, polyester resins are applied to various molding applications such as bottles.

[0003] In recent years, from the viewpoints of resource reuse and global environmental protection, attention has been focused on technologies for collecting waste polyester resins that have been used once and recycling them as recycled polyester resins.

[0004] For example, Patent Document 1 discloses a resin composition containing a polyester resin recycled from a polyester resin molded product and a resin other than polyester, and a molded product thereof.

[0005] Also, as a modifier for use during extrusion molding using recycled polyester resins, for example, Patent Document 2 discloses a polyester resin modifier containing an amorphous polyester resin (I), a reactive compound (II), and a lubricant (III).

Prior Art Documents

Patent Documents

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in conventional injection molding and blow molding using polyester resins, premature crystallization of the resin can be a problem; for example, blow molding may not be completed sufficiently due to crystallization. In other words, conventional techniques are insufficient from the standpoint of preventing the crystallization of polyester resins, and there is room for further improvement.

[0008] One embodiment of the present invention has been made in view of the above-mentioned problems, and its objective is to provide a novel method that can suppress the crystallization of polyester resins. [Means for solving the problem]

[0009] The present inventors have diligently studied and, as a result, completed the present invention. That is, one embodiment of the present invention includes the following configuration. [1] A method for suppressing crystallization of a polyester resin, comprising a mixing step of mixing a crystalline polyester resin (A) and an amorphous polyester resin (B). [2] The method for suppressing crystallization of a polyester resin according to [1], wherein in the mixing step, a modifier (C) is further mixed, and the modifier (C) comprises a polymer (C1) containing a reactive functional group-containing unit and a reactive functional group-free unit. [3] The method for suppressing crystallization of a polyester resin according to [2], wherein the modifier (C) further comprises a polymer (C2) containing a reactive functional group-containing unit, and the content of the polymer (C1) and the polymer (C2) in the modifier (C) is 50% to 90% by weight of the polymer (C1) and 10% to 50% by weight of the polymer (C2) per 100% of the modifier (C). [4] The method for suppressing the crystallization of a polyester resin according to any one of [1] to [3], wherein the amount of amorphous polyester resin (B) used in the method for suppressing the crystallization of the polyester resin is 5% to 60% by weight of the total amount of crystalline polyester resin (A) and amorphous polyester resin (B) used, 100% by weight. [5] The method for suppressing crystallization of a polyester resin according to any one of [1] to [4], wherein the amorphous polyester resin (B) contains glycol-modified polyethylene terephthalate. [6] The method for suppressing crystallization of a polyester resin according to any one of [1] to [5], wherein the crystalline polyester resin (A) includes a recycled polyester resin. [7] The method for suppressing crystallization of a polyester resin according to [3], wherein the content of the reactive functional group-containing unit in the polymer (C2) is 0.5% by weight to 10.0% by weight of 100% by weight of the polymer (C2). [8] The method for suppressing crystallization of a polyester resin according to [3] or [7], wherein the reactive functional group-containing unit in the polymer (C2) includes an epoxy group-containing (meth)acrylate unit. [9] The method for suppressing crystallization of a polyester resin according to any one of [3], [7], and [8], wherein the polymer (C2) further comprises aromatic vinyl units and / or (meth)acrylic units as constituent units.

[10] The method for suppressing crystallization of a polyester resin according to [2] or [3], wherein the polymer (C1) has an average of 2 to 10 of the reactive functional groups per molecule.

[11] The number average molecular weight of the polymer (C1) is 2,000 Da to 10,000 Da, a method for suppressing crystallization of a polyester resin according to any one of [2], [3], and

[10] .

[12] The polymer (C1) is (i) The reactive functional group-containing unit includes an epoxy group-containing (meth)acrylate unit, (ii) A method for suppressing crystallization of a polyester resin according to any one of [2], [3],

[10] , and

[11] , wherein the reactive functional group-free unit includes one or more constituent units selected from the group consisting of reactive functional group-free aromatic vinyl units and reactive functional group-free (meth)acrylate units.

[13] The method for suppressing the crystallization of a polyester resin according to any one of [2], [3] and

[10] to

[12] , wherein the amount of the modifier (C) used in the method for suppressing the crystallization of the polyester resin is 0.2 parts by weight to 10.0 parts by weight per 100 parts by weight of the total amount of the crystalline polyester resin (A) and the amorphous polyester resin (B) used.

[14] The method for suppressing crystallization of a polyester resin according to any one of [1] to

[13] , wherein the crystalline polyester resin (A) comprises one or more selected from the group consisting of polyethylene terephthalate and polybutylene terephthalate. A method for producing an injection-molded article, comprising the step of injection molding a polyester resin composition obtained through a method for suppressing the crystallization of a polyester resin described in any one of [1] to

[14] . A method for manufacturing a blow-molded article, comprising: step 1 of injection molding a polyester resin composition obtained through a method for suppressing the crystallization of a polyester resin described in any one of [1] to

[14] ; and step 2 of blow molding the injection-molded article obtained in step 1. [Effects of the Invention]

[0010] One embodiment of the present invention provides a novel method that can suppress the crystallization of polyester resins. [Modes for carrying out the invention]

[0011] 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)."

[0012] Unless otherwise specified in this specification, constituent units contained in polymers, copolymers, or resins are referred to as "constituent units derived from X monomers," "constituent units derived from X compounds," or "constituent units derived from X acids," respectively.

[0013] [1. Technical Concept of One Embodiment of an Embodiment] One type of blow molding is injection blow molding. Injection blow molding is a molding method in which a molded body obtained by injection molding is heated, and air is blown into the molded body to form the product. Injection molding is synonymous with injection molding, and a molded body obtained by injection molding can also be called an injection-molded body. In injection blow molding, the injection-molded body used for blow molding is sometimes called a "preform."

[0014] In the process of diligently studying blow molding of polyester resins, the inventors independently discovered that when a preform is heated, it may not be possible to sufficiently inflate the preform with air. The inventors also independently discovered that when recycled polyester resin is used as the raw material, the aforementioned insufficient inflation of the preform occurs frequently.

[0015] As a result of examining the cause of insufficient swelling of the preform, the inventor presumed, though not certain, that the cause might be impurities that might be contained in the polyester resin (for example, recycled polyester resin) as a raw material. Note that one embodiment of the present invention is not limited to such presumption at all.

[0016] For example, on the surface of a polyester resin film used in the production of ceramic capacitors, (i) silicone cone and / or acrylic resin may be coated or multi-layered in order to suppress the adhesion of ceramics. Therefore, in many cases, silicone cone, acrylic resin and / or ceramics adhere to the surface of the exhausted polyester resin film. When recycling the polyester resin film, components other than the polyester resin on the surface of the polyester resin film (such as silicone cone, acrylic resin and / or ceramics) are removed as much as possible, but cannot be completely removed, and the obtained recycled polyester resin may contain the above-mentioned components other than the polyester resin.

[0017] As a result of further examining the cause of insufficient swelling of the preform, the inventor proposed an original hypothesis that the cause is that the polyester resin crystallizes relatively quickly during preform molding and / or during reheating of the preform before blow molding. Based on such a hypothesis, the inventor has intensively studied to develop a new method for suppressing the crystallization of the polyester resin.

[0018] As a result, the inventor independently obtained a new finding that the crystallization of the polyester resin can be suppressed by blending an amorphous polyester resin with a crystalline polyester resin, and thus completed the present invention.

[0019] 〔2. Method for Suppressing Crystallization of Polyester Resin〕 A method for suppressing crystallization of a polyester resin according to one embodiment of the present invention comprises a mixing step of mixing a crystalline polyester resin (A) and an amorphous polyester resin (B).

[0020] In this specification, "method for suppressing crystallization of polyester resin" may be referred to as "crystallization suppression method," and "method for suppressing crystallization of polyester resin according to one embodiment of the present invention" may be referred to as "this crystallization suppression method."

[0021] In the mixing step, a composition containing a crystalline polyester resin (A) and an amorphous polyester resin (B) can be obtained. In this specification, the "composition containing a crystalline polyester resin (A) and an amorphous polyester resin (B)" may also be referred to as a "polyester resin composition" or "resin composition."

[0022] This crystallization suppression method has the advantage of being able to provide a polyester resin composition in which the crystallization of the polyester resin is suppressed, because it has the configuration described above. This crystallization suppression method has the advantage of being able to provide a polyester resin composition in which the crystallization of the polyester resin can be suppressed, particularly during preform molding and / or when reheating the preform before blow molding. In this specification, "crystallization suppressed" means that crystallization is prevented or reduced. The polyester resin composition obtained through this crystallization suppression method is also one embodiment of the present invention. The degree of crystallization of the polyester resin in a polyester resin composition can be evaluated by the transparency (degree of whiteness) of the molded article (e.g., film) obtained from the polyester resin composition after being left at a certain temperature for a certain period of time. A white molded article means that the polyester resin has crystallized. In this specification, "a polyester resin composition in which the crystallization of the polyester resin is suppressed" means that even when a molded article (film) made from the polyester resin composition is left at 120°C for 2 minutes, the molded article (film) is transparent or partially (but not entirely) white.

[0023] Furthermore, the polyester resin composition obtained through this crystallization suppression method has the advantage that crystallization of the polyester resin can be suppressed even during injection molding. As a result, the polyester resin composition has the advantage of providing an injection molded article with excellent impact strength.

[0024] Below, we will first explain the raw materials (crystalline polyester resin (A) and amorphous polyester resin (B), etc.), and then describe the specific manufacturing process.

[0025] (Crystalline polyester resin (A)) In this specification, "crystalline polyester resin" means a thermoplastic polyester resin that may have crystalline portions in which polymer molecules are regularly aligned when in a non-molten state. As long as it is such a polyester resin, the crystalline polyester resin (A) is not particularly limited.

[0026] 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.

[0027] Aromatic dicarboxylic acids are not particularly limited, but examples include 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'-diphenyletherdicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 4,4'-diphenylisopropylidenedicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, 2,5-anthracenedicarboxylic acid, 2,6-anthracenedicarboxylic acid, 4,4'-p-terphenylenedicarboxylic acid, and 2,5-pyridinedicarboxylic acid. One type of aromatic dicarboxylic acid may be used, or two or more types may be used in combination.

[0028] 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, and triethylene glycol. Alicyclic diols are not particularly limited, but examples include 1,4-cyclohexanedimethanol. Only one type of diol component may be used, or two or more types may be used in combination.

[0029] The polyester resin may have structural components derived from trifunctional or more monomers such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, and pyromellitic acid.

[0030] The crystalline nature of polyester resins can usually be confirmed by the presence of a distinct endothermic peak in differential scanning calorimetry (DSC). Specifically, a distinct endothermic peak refers to an endothermic peak in the DSC curve obtained by differential scanning calorimetry (DSC) performed at a heating rate of 10°C / min, where the full width at half maximum (FMAX) is, for example, within 15°.

[0031] Specific examples of crystalline polyester resin (A) are not particularly limited, but include polyethylene terephthalate (PET), 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, and the like.

[0032] From the viewpoint of moldability and mechanical properties, the crystalline polyester resin (A) preferably contains (i) one or more selected from the group consisting of polyethylene terephthalate, 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 the group; and (ii) more preferably contains one or more selected from the group consisting of polyethylene terephthalate and polybutylene terephthalate, and may consist only of one or more selected from the group.

[0033] The crystalline polyester resin (A) may contain recycled polyester resin, or it may consist solely of recycled polyester resin. As mentioned above, recycled polyester resin may contain impurities that can promote the crystallization of the resin. Therefore, when the crystalline polyester resin (A) contains recycled polyester resin, there is great significance in applying this crystallization suppression method.

[0034] In this specification, "recycled polyester resin" refers to polyester resins and / or polyester resin compositions obtained by recycling the following (Ai) and / or (Aii): (Ai) Polyester resin, polyester resin composition, and / or polyester resin molded articles that have been used and / or discarded after being commercialized as polyester resin, polyester resin composition, and / or polyester resin molded articles; (Aii) Polyester resins, polyester resin compositions, and / or polyester resin molded articles that are discharged and discarded during the manufacturing process of polyester resins, polyester resin compositions, and / or polyester resin molded articles.

[0035] The aforementioned recycling method can be any known recycling method, and is not particularly limited; for example, material recycling can be used.

[0036] When the crystalline polyester resin (A) 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."

[0037] In this specification, polyester resins that have never been commercialized may be referred to as "virgin polyester resins." In this specification, "recycled polyester resins" also include mixtures obtained by mixing "virgin polyester resins" with recycled polyester resins.

[0038] <Amorphous polyester resin (B)> In this specification, "amorphous polyester resin" refers to a highly transparent polyester resin that substantially lacks a crystalline structure. As long as it is such a polyester resin, the amorphous polyester resin (B) is not particularly limited.

[0039] By incorporating an amorphous polyester resin (B), it is possible to provide a polyester resin composition in which the crystallization of the polyester resin, particularly the crystalline polyester resin (A), is suppressed.

[0040] 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.

[0041] Aromatic dicarboxylic acids are not particularly limited, but examples include 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'-diphenyletherdicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 4,4'-diphenylisopropylidenedicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, 2,5-anthracenedicarboxylic acid, 2,6-anthracenedicarboxylic acid, 4,4'-p-terphenylenedicarboxylic acid, and 2,5-pyridinedicarboxylic acid. One type of aromatic dicarboxylic acid may be used, or two or more types may be used in combination.

[0042] 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, and triethylene glycol. Alicyclic diols are not particularly limited, but examples include 1,4-cyclohexanedimethanol. Only one type of diol component may be used, or two or more types may be used in combination.

[0043] The polyester resin may have structural components derived from trifunctional or more monomers such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, and pyromellitic acid.

[0044] The amorphous nature of polyester resins can usually be confirmed by the absence of a distinct endothermic peak in differential scanning calorimetry (DSC). A distinct endothermic peak is, specifically, an endothermic peak in the DSC curve obtained by differential scanning calorimetry (DSC) performed at a heating rate of 10°C / min, where the full width at half maximum (FMAX) is, for example, 15° or less.

[0045] The amorphous polyester resin (B) is preferably 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 that imparts amorphous properties.

[0046] Examples of dicarboxylic acids that impart amorphous properties include isophthalic acid, phthalic acid, aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis(4,4-carboxyphenyl)methane, anthracenedicarboxylic acid, and 4,4'-diphenyl ether carboxylic acid, as well as alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and 4,4'-dicyclohexyldicarboxylic acid.

[0047] Examples of diols that impart amorphous properties include 1,4-cyclohexanedimethanol, propylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, decamethylene glycol, 4,4-dicyclohexylhydroxymethane, 4,4'-dicyclohexylhydroxypropane, bisphenol A ethylene oxide adduct diol, polyethylene oxide glycol, and polypropylene oxide glycol.

[0048] The amorphous polyester resin (B) preferably contains glycol-modified polyethylene terephthalate, and more preferably consists solely of glycol-modified polyethylene terephthalate. "Glycol-modified polyethylene terephthalate" refers to a copolymer of terephthalic acid, ethylene glycol, and a glycol component other than ethylene glycol.

[0049] The amorphous polyester resin (B) may contain recycled polyester resin, or may consist solely of recycled polyester resin.

[0050] In this crystallization suppression method, the amounts of crystalline polyester resin (A) and amorphous polyester resin (B) used are not particularly limited. From the viewpoint of further suppressing the crystallization of the polyester resin, a larger amount of amorphous polyester resin (B) is preferable. From the viewpoint of allowing the physical properties derived from the crystalline polyester resin (A) (e.g., chemical resistance and abrasion resistance) to be fully exhibited, a smaller amount of amorphous polyester resin (B) is preferable. From these viewpoints, in this crystallization suppression method, the amounts of crystalline polyester resin (A) and amorphous polyester resin (B) used are preferably 5% to 60% by weight, more preferably 8% to 50% by weight, more preferably 10% to 40% by weight, more preferably 13% to 30% by weight, and particularly preferably 15% to 25% by weight of amorphous polyester resin (B) out of 100% by weight of the total amount of crystalline polyester resin (A) and amorphous polyester resin (B) used.

[0051] <Modifier (C)> In the mixing step, a modifier (C) may be further mixed. In other words, the mixing step may be a step of mixing a crystalline polyester resin (A), an amorphous polyester resin (B), and a modifier (C).

[0052] In this specification, "modifier" means "an agent that can change the physical properties of a polyester resin (for example, improve the melt viscosity)." Modifier (C) comprises a polymer (C1) containing reactive functional group-containing units and reactive functional group-free units. With this configuration, modifier (C) can change the physical properties of a polyester resin, for example, a crystalline polyester resin (A) (for example, improve the melt viscosity). More specifically, modifier (C) can react with a polyester resin, for example, a crystalline polyester resin (A), by comprising a polymer (C1) containing reactive functional group-containing units and reactive functional group-free units. This reaction can change the physical properties of the polyester resin, for example, a crystalline polyester resin (A) (for example, improve the melt viscosity). In this specification, "melt viscosity of polyester resin" and "melt viscosity of polyester resin composition" refer to values ​​obtained by the methods described in the later examples.

[0053] Polyester resins can deteriorate with each processing step (e.g., melt mixing), for example, due to heat, which can shorten the molecular chains of the resin and reduce its physical properties. The physical properties of recycled polyester resins obtained by recycling polyester resin products, such as melt viscosity, may be inferior (lower) compared to the physical properties of the polyester resin used as the raw material for those products, such as melt viscosity.

[0054] When a modifier (C) is further mixed in the mixing process, it has the advantage of improving the physical properties of the polyester resin (e.g., crystalline polyester resin (A) and / or amorphous polyester resin (B)), such as melt viscosity. When the crystalline polyester resin (A) includes recycled polyester resin, it is particularly significant to further mix in a modifier (C) in the mixing process that can improve the physical properties (e.g., melt viscosity) of the recycled polyester resin.

[0055] (C1 polymer) Polymer (C1) includes units containing reactive functional groups and units not containing reactive functional groups.

[0056] (Units containing reactive functional groups) In this specification, "reactive functional group" means a functional group that can react with terminal functional groups of polyester resins. In this specification, "reactive functional group-containing unit" means a constituent unit having a reactive functional group, and is a constituent unit derived from a monomer having a reactive functional group (hereinafter sometimes referred to as "reactive functional group-containing monomer").

[0057] In the mixing process, the reactive functional groups (e.g., epoxy groups) of the reactive functional group-containing units in the polymer (C1) contained in the modifier (C) may react with the terminal functional groups (e.g., hydroxyl groups or carboxyl groups) of the polyester resin (e.g., crystalline polyester resin (A) and / or amorphous polyester resin (B)), and such a reaction may elongate the molecular chains of the polyester resin. In other words, the polymer (C1) contained in the modifier (C) may have the function of elongating the molecular chains of the polyester resin, or to put it another way, the polymer (C1) contained in the modifier (C) may function as a chain extender (or viscosity modifier) ​​for the polyester resin. Furthermore, by including the polymer (C1) described above in the modifier (C), the modifier (C) and the polyester resin may be mixed more uniformly in the mixing process, i.e., the dispersibility of the modifier (C) may be improved. As a result of improving the dispersibility of the modifier (C) and extending the molecular chains of the polyester resin, the melt viscosity (IV value) of the polyester resin can be improved, and a resin composition with a higher melt viscosity than the polyester resin can be obtained. However, the present invention is not limited in any way to these assumptions.

[0058] As described above, during the mixing process, the reactive functional groups (e.g., epoxy groups) of the reactive functional group-containing units in the polymer (C1) contained in the modifier (C) may react with the terminal functional groups (e.g., hydroxyl groups or carboxyl groups) of the polyester resin (e.g., crystalline polyester resin (A) and / or amorphous polyester resin (B)). Therefore, in the modifier (C) before mixing with the crystalline polyester resin (A) and amorphous polyester resin (B) in the mixing process, the reactive functional group-containing units exist in a state where they are reacting with the terminal functional groups of the polyester resin. On the other hand, in the resin composition obtained in the mixing process, as a result of the reaction between the modifier (C) and the polyester resin, at least a portion of the modifier (C) may exist as constituent units derived from the modifier (C). Therefore, in the constituent units derived from the modifier (C) in the resin composition obtained in the mixing process, at least a portion of the reactive functional group-containing units may exist in a state where they are covalently bonded to the terminals of the polyester resin units in the resin composition.

[0059] The reactive functional group is not particularly limited as long as it is a functional group that can react with the terminal functional groups of the polyester resin, and may be, for example, at least one functional group selected from the group consisting of epoxy groups, oxetane groups, hydroxyl groups, amino group-containing monomers, imide groups, carboxylic acid groups, and carboxylic acid anhydride groups.

[0060] The reactive functional group-containing units may be constituent units derived from cyclic ester-containing monomers and constituent units derived from cyclic amide-containing monomers.

[0061] In this specification, a "reactive functional group-containing monomer having an X group as a reactive functional group" may be referred to as an "X group-containing monomer," and a "constituent unit derived from a reactive functional group-containing monomer having an X group as a reactive functional group," that is, a "constituent unit having an X group as a reactive functional group," may be referred to as an "X group-containing unit."

[0062] Specific examples of epoxy group-containing monomers include glycidyl group-containing vinyl monomers such as glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, 3,4-epoxycyclohexyl (meth)acrylate, allyl glycidyl ether, β-methylglycidyl (meth)acrylate, and 4-vinylbenzyl glycidyl ether. Among these, glycidyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate glycidyl ether are preferred as epoxy group-containing monomers from the viewpoint of reactivity, glycidyl methacrylate and 4-hydroxybutyl acrylate glycidyl ether are more preferred, and glycidyl methacrylate is even more preferred. In this specification, "(meth)acrylate" means "acrylate and / or methacrylate".

[0063] Specific examples of oxetane group-containing monomers include, for example, (vinyloxyalkyl)alkyloxetane, (meth)acryloyloxyalkyloxetane, and [(meth)acryloyloxyalkyl]alkyloxetane. In this specification, "(meth)acryloyl" means "acryloyl and / or methacryloyl."

[0064] Specific examples of hydroxyl group-containing monomers include, for example, (a) hydroxylinear alkyl(meth)acrylates such as 2-hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate (particularly preferred are hydroxylinear C1-6 alkyl(meth)acrylates); (b) caprolactone-modified hydroxy(meth)acrylates; (c) hydroxybranched alkyl(meth)acrylates such as methyl α-(hydroxymethyl)(meth)acrylate and ethyl α-(hydroxymethyl)(meth)acrylate; (d) hydroxyl group-containing (meth)acrylates such as mono(meth)acrylates of polyester diols obtained from divalent carboxylic acids (such as phthalic acid) and divalent alcohols (such as propylene glycol) (particularly preferred are saturated polyester diols); and (e) hydroxyl group-containing maleates. Note that "linear C1-6 alkyl" refers to linear alkyls having 1 to 6 carbon atoms. In this specification, "(meth)acrylic acid" means "acrylic acid and / or methacrylic acid."

[0065] Specific examples of amino group-containing monomers include, for example, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, N,N-diethylaminopropyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylamide, N,N-diethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, N,N-diethylaminopropyl (meth)acrylamide, 2-vinylpyridine, 4-vinylpyridine, and compounds having a structure obtained by neutralizing these with an acid represented by H+X-.

[0066] Specific examples of imide group-containing monomers include maleimide, phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, Nt-butylmaleimide, N-cyclohexylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-bromophenylmaleimide, N-naphthylmaleimide, N-laurylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N-nitrophenylmaleimide, and N-benzylmaleimide.

[0067] Specific examples of monomers containing carboxylic acid groups include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, as well as dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid. From the viewpoint of reactivity, monocarboxylic acids are preferred as monomers containing carboxylic acid groups.

[0068] Specific examples of monomers containing carboxylic acid anhydride groups include, for example, maleic anhydride.

[0069] The reactive functional group-containing units in polymer (C1) may consist of (i) only one reactive functional group-containing unit derived from any one of the reactive functional group-containing monomers described above, or (ii) any combination of two or more reactive functional group-containing units derived from any two or more reactive functional group-containing monomers described above.

[0070] From the viewpoint of obtaining a polyester resin composition with improved melt viscosity (IV value) through the reaction of the crystalline polyester resin (A) and the modifier (C), the reactive functional group-containing units in the polymer (C1) preferably include one or more selected from the group consisting of epoxy group-containing units, hydroxyl group-containing units, carboxylic acid group-containing units, and carboxylic acid anhydride group-containing units, and may consist only of one or more selected from the group, and (ii) epoxy group-containing (meth)acrylate units, hydroxyl group-containing maleate units, monocarboxylic acid units, dicarboxylic acid units, and carboxylic acid anhydride units. It is even more preferable to include one or more selected from the group consisting of water group-containing units, and it may consist of only one or more selected from said group; (iii) It is even more preferable to include one or more selected from the group consisting of epoxy group-containing (meth)acrylate units, hydroxyl group-containing maleate units, acrylic acid units, methacrylic acid units, maleic acid units, and maleic anhydride units, and it may consist of only one or more selected from said group; (iv) It is particularly preferable to include epoxy group-containing (meth)acrylate units, and it may consist of only epoxy group-containing (meth)acrylate units.

[0071] From the viewpoint of polymerization productivity of reactive functional group-containing monomers from which reactive functional group-containing units are derived, the reactive functional group-containing units in polymer (C1) preferably contain one or more selected from the group consisting of (i) glycidyl (meth)acrylate units, 4-hydroxybutyl (meth)acrylate glycidyl ether units, 3,4-epoxycyclohexyl (meth)acrylate units and β-methylglycidyl (meth)acrylate units, and may consist only of one or more selected from the group, and (ii) glycidyl (meth)acrylate units, 4-hydroxybutyl acrylate glycidyl (iii) It is more preferable to include one or more selected from the group consisting of ether units and 3,4-epoxycyclohexyl (meth)acrylate units, and it may consist of only one or more selected from said group; (iv) It is most preferable to include glycidyl (meth)acrylate units and 4-hydroxybutyl acrylate glycidyl ether units, and it may consist of only one or more selected from said group; (iv) It is most preferable to include glycidyl methacrylate units, and it may consist of only glycidyl methacrylate units.

[0072] The content of reactive functional group-containing units in polymer (C1) is not particularly limited, but is preferably 5% to 60% by weight per 100% by weight of polymer (C1). The upper limit of the content may be 55%, 50%, 45%, or 40% by weight, and the lower limit may be 7%, 10%, 15%, 20%, 25%, or 30% by weight. If the content of reactive functional group-containing units in polymer (C1) is within the above range, the effect of improving the melt viscosity of the polyester resin by the modifier (C) can be good. As a result, even if, for example, the crystalline polyester resin (A) and / or amorphous polyester resin (B) include recycled polyester resin, it is possible to obtain a resin composition with a melt viscosity high enough to mold a bottle with excellent strength.

[0073] The content of epoxy group-containing (meth)acrylate units in polymer (C1) is not particularly limited, but is preferably 5% to 60% by weight per 100% by weight of polymer (C1). The upper limit of the content may be 55%, 50%, 45%, or 40% by weight, and the lower limit may be 7%, 10%, 15%, 20%, 25%, or 30% by weight. If the content of epoxy group-containing units in polymer (C1) is within the above range, the effect of improving the melt viscosity of the resin composition by the modifier (C) may be better. As a result, even if, for example, the crystalline polyester resin (A) and / or amorphous polyester resin (B) include recycled polyester resin, it is possible to obtain a resin composition with a melt viscosity high enough to mold a bottle with superior strength.

[0074] (Units without reactive functional groups) In this specification, "reactive functional group-free units" are constituent units derived from monomers that do not have reactive functional groups capable of reacting with the terminal functional groups of polyester resins (hereinafter sometimes referred to as "reactive functional group-free monomers"). In other words, reactive functional group-free units contained in the polymer (C1) of modifier (C) cannot react with the terminal functional groups of polyester resins. Furthermore, reactive functional group-free units in polymer (C1) are also constituent units derived from monomers copolymerizable with monomers containing reactive functional groups in polymer (C1).

[0075] The reactive functional group-free monomer from which the reactive functional group-free unit in polymer (C1) originates is not particularly limited. Examples of such reactive functional group-free monomers include reactive functional group-free (meth)acrylic monomers, reactive functional group-free vinyl cyanide compounds, and reactive functional group-free aromatic vinyl compounds.

[0076] Specific examples of reactive functional group-free (meth)acrylic monomers include, for example, (meth)acrylic acid and reactive functional group-free (meth)acrylates. "Reactive functional group-free (meth)acrylate" refers to "(meth)acrylate ((meth)acrylic acid ester) that does not have a reactive functional group and is substituted or unsubstituted with a functional group other than a reactive functional group." Specific examples of reactive functional group-free (meth)acrylates include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, ocryl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate, which are alkyl (meth)acrylates without reactive functional groups and having alkyl groups with 1 to 22 carbon atoms.

[0077] The number of carbon atoms in the alkyl group in the reactive functional group-free alkyl (meth)acrylate unit is not particularly limited. From the viewpoint of the polymerizability of the monomer from which the constituent unit is derived, it is preferable that the number of carbon atoms in the alkyl group in the reactive functional group-free alkyl (meth)acrylate unit is 22 or less. Furthermore, from the viewpoint of compatibility with polyester resins, it is more preferable that the number of carbon atoms in the alkyl group in the reactive functional group-free alkyl (meth)acrylate unit is 12 or less, even more preferable that it is 8 or less, and particularly preferable that it is 1 to 4.

[0078] Specific examples of vinyl cyanide compounds that do not contain reactive functional groups include, for example, acrylonitrile and methacrylonitrile.

[0079] Specific examples of reactive functional group-free aromatic vinyl compounds include, for example, reactive functional group-free styrene monomers and 1-vinylnaphthalene. In this specification, "reactive functional group-free styrene monomer" means "styrene that does not have a reactive functional group and is substituted or unsubstituted with a functional group other than a reactive functional group." Specific examples of reactive functional group-free styrene monomers include, for example, 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, and 2,6-dichlorostyrene.

[0080] The reactive functional group-free units in polymer (C1) may consist of (i) only one reactive functional group-free unit derived from any one of the reactive functional group-free monomers described above, or (ii) any combination of any two or more reactive functional group-free units derived from any two or more reactive functional group-free monomers described above.

[0081] From the viewpoint of obtaining a polyester resin composition with improved melt viscosity (IV value) through the reaction of the crystalline polyester resin (A) and the modifier (C), the reactive functional group-free units in the polymer (C1) preferably include one or more constituent units selected from the group consisting of (i) reactive functional group-free aromatic vinyl units and reactive functional group-free (meth)acrylic units, and may consist only of one or more constituent units selected from the group; (ii) more preferably include one or more constituent units selected from the group consisting of reactive functional group-free aromatic vinyl units and reactive functional group-free (meth)acrylate units, and may consist only of one or more constituent units selected from the group; and (iii) reactive functional group-free styrene units and reactive functional group-free (meth)acrylic units It is more preferable to include one or more constituent units selected from the group consisting of methyl methacrylate units, and it may consist only of one or more constituent units selected from said group; (iv) It is even more preferable to include one or more constituent units selected from the group consisting of 4-methylstyrene units, 3-methylstyrene units, α-methylstyrene units, styrene units, methyl (meth)acrylate units, ethyl (meth)acrylate units, propyl (meth)acrylate units, and butyl (meth)acrylate units, and it may consist only of one or more constituent units selected from said group; (v) It is particularly preferable to include one or more constituent units selected from the group consisting of styrene units, methyl methacrylate units, and butyl acrylate units, and it may consist only of one or more constituent units selected from said group.

[0082] The total content of reactive functional group-free units in polymer (C1) is not particularly limited, but is preferably 40% to 95% by weight of polymer (C1) per 100% by weight. The upper limit of the content may be 93%, 90%, 85%, 80%, 75%, or 70% by weight, and the lower limit may be 45%, 50%, 55%, or 60% by weight. If the total content of reactive functional group-free units in polymer (C1) is within the above range, the dispersibility of the modifier (C) can be improved in the mixing process, thereby improving the melt viscosity of the polyester resin by the modifier (C). As a result, even if, for example, the crystalline polyester resin (A) and / or amorphous polyester resin (B) include recycled polyester resin, it is possible to obtain a resin composition with a melt viscosity high enough to mold a bottle with excellent strength.

[0083] The total content of reactive functional group-free aromatic vinyl units and reactive functional group-free (meth)acrylic units in polymer (C1) is not particularly limited, but is preferably 40% to 95% by weight per 100% by weight of polymer (C1). The upper limit of the content may be 93%, 90%, 85%, 80%, 75%, or 70% by weight, and the lower limit may be 45%, 50%, 55%, or 60% by weight. If the total content of reactive functional group-free aromatic vinyl units and reactive functional group-free (meth)acrylic units in polymer (C1) is within the above range, the dispersibility of the modifier (C) can be further improved in the mixing process, thereby improving the melt viscosity of the polyester resin by the modifier (C). As a result, even if, for example, the crystalline polyester resin (A) and / or amorphous polyester resin (B) include recycled polyester resin, it is possible to obtain a resin composition with a high melt viscosity to the extent that it is possible to mold a bottle with superior strength. Furthermore, if the upper and lower limits of the content (number average) of reactive functional groups per molecule of polymer (C1) are within the aforementioned preferred 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 polyester resin fibers.

[0084] The number-average content of reactive functional groups in polymer (C1) is not particularly limited. It is preferable that polymer (C1) has 2 to 10 reactive functional groups per molecule on average. The upper limit of reactive functional groups in polymer (C1) may be 8 or less, 7 or less, 6 or less, or 5 or less. The lower limit of reactive functional groups in polymer (C1) may be 3 or more, 4 or more, 5 or more, 6 or more, or 7 or more. When the number-average content of reactive functional groups in polymer (C1) is within the above-mentioned range, the melt viscosity of the polyester resin can be suitably improved without causing gelation and without impairing mechanical properties, heat resistance, and rheological properties. In this specification, the "number-average content of reactive functional groups" per molecule of the polymer is the value obtained by the method described in the later examples.

[0085] The number-average molecular weight of polymer (C1) is not particularly limited. From the viewpoint of balancing the thermal stability and productivity of polymer (C1) and improving the melt viscosity of the polyester resin, the number-average molecular weight of polymer (C1) is preferably 2,000 Da to 10,000 Da. The upper limit of the number-average molecular weight of polymer (C1) is more preferably 8,000 Da or less, even more preferably 7,000 Da or less, and particularly preferably 6,000 Da or less. The lower limit of the number-average molecular weight of polymer (C1) is more preferably 3,000 Da or more, even more preferably 4,000 Da or more, even more preferably 5,000 Da or more, and particularly preferably 6,000 Da or more. In this specification, the "number-average molecular weight" of the polymer is the value obtained by the method described in the later examples.

[0086] The polymer (C1) 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 (C1) being a non-rubber polymer is that the reaction between the reactive functional groups (e.g., epoxy groups) of polymer (C1) and the terminal functional groups of the polyester resin proceeds more efficiently, making it easier to improve the melt viscosity of the resin composition.

[0087] (Method for producing polymer (C1)) The polymerization method for polymer (C1) can be any known method and is not particularly limited. For example, bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., can be used as the polymerization method for polymer (C1), but emulsion polymerization is preferred.

[0088] When producing polymer (C1), it is preferable to carry out polymerization in the presence of a chain transfer agent in order to control the molecular weight. It is preferable to use a chain transfer agent in the production of polymer (C1). Polymers obtained using a chain transfer agent may contain structural units derived from the chain transfer agent. In other words, it is preferable that the polymer (C1) contains structural units derived from the chain transfer agent.

[0089] 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, trimethylolpropane tris(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; terpinolenes; and others. 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 the polymer (C1).

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] Known surfactants can also be used during the polymerization of polymer (C1).

[0095] When polymer (C1) is produced by emulsion polymerization, a latex containing polymer (C1) (e.g., aqueous latex) can be obtained. Polymer (C1) can be obtained by separating polymer (C1) from the latex containing polymer (C1). The obtained polymer (C1) can be used as a modifier (C). There are no particular limitations on the method for separating polymer (C1) from latex containing polymer (C1), but examples include salting out of polymer (C1) using an acid and a metal salt, and precipitation of polymer (C1) using an organic solvent. Polymer (C1) separated from latex containing polymer (C1) may be washed and further dried. By separating polymer (C1) from latex containing polymer (C1), washing, and further drying, polymer (C1) powder (also referred to as "powder") can be obtained. Polymer (C1) powder can also be obtained by spray drying the latex containing polymer (C1). The polymer (C1) powder obtained in this way can be used as a modifier (C).

[0096] [mix(C2)] The modifier (C) may or may not contain a polymer (C2) containing a reactive functional group unit in addition to polymer (C1). The polymer component in modifier (C) may consist only of polymer (C1), may consist only of polymer (C1) and polymer (C2), or may consist of polymer (C1), polymer (C2), and other polymers.

[0097] The case in which the modifier (C) includes polymer (C1) and polymer (C2) (hereinafter also referred to as "Case A") will be described below. In Case A, it is preferable to polymerize polymer (C1) and then polymerize polymer (C2) in the presence of polymer (C1). In Case A, if polymer (C1) is obtained by emulsion polymerization, for example, it is particularly preferable to produce polymer (C2) in latex containing polymer (C1) after producing polymer (C1). When polymer (C2) is produced in latex containing polymer (C1), a composite consisting of polymer (C1) and polymer (C2) (or containing polymer (C1) and polymer (C2)) can be obtained. In the composite, polymer (C2) may cover a part of polymer (C1). Therefore, in the composite, polymer (C1) can be referred to as the core part and polymer (C2) as the shell part. The composite may have a core-shell structure, with polymer (C1) as the core and polymer (C2) as the shell. In other words, when polymer (C2) is produced (polymerized) in latex containing polymer (C1), a composite consisting of polymer (C1) and polymer (C2) can be obtained, in which polymer (C1) forms the core and polymer (C2) forms the shell, i.e., a composite having a core-shell structure. In the composite, polymer (C2) may cover the entire polymer (C1), or at least a portion of polymer (C2) may be impregnated into the interior of particulate polymer (C1).

[0098] When the modifier (C) comprises polymer (C1) and polymer (C2), and the composite composed of polymer (C1) and polymer (C2) has a core-shell structure in which polymer (C1) forms the core and polymer (C2) forms the shell, it has the advantage of improving productivity.

[0099] As long as polymer (C2) contains reactive functional group-containing units, its other components are not particularly limited. The composition of the constituent units of polymer (C2) may be the same as or different from the composition of the constituent units of polymer (C1). In other words, the composition of monomer mixture (B) may be the same as or different from the composition of monomer mixture (A).

[0100] In case A, it is preferable that polymer (C1) and polymer (C2) are not chemically bonded together. If polymer (C1) and polymer (C2) are not chemically bonded together, polymer (C1) and polymer (C2) may exist separately from each other in the resulting resin composition.

[0101] In case A, it is particularly preferable that the polymer (C2) has a configuration that allows it to more uniformly disperse the polymer (C1) in the polyester resin, in other words, to function as a carrier, so that the polymer (C1), which can function as a chain extender, reacts more uniformly with the polyester resin when the modifier (C) and the polyester resin are mixed.

[0102] It is particularly preferable that polymer (C2) has a configuration that can improve the granulation properties during the production of modifier (C). When polymer (C1) is polymerized alone and powdered, it may become a fine powder that is difficult to handle. In such cases, polymer (C2) having a configuration that facilitates granulation (powdering) can be polymerized together with polymer (C1), and by isolating polymers (C1) and (C2) together, a modifier (C) with excellent handling properties can be obtained.

[0103] The polymer (C2) may consist only of reactive functional group-containing units. Preferably, the polymer (C2) contains both reactive functional group-containing units and reactive functional group-free units. When the polymer (C2) contains both reactive functional group-containing units and reactive functional group-free units, the softening point of the modifier (C) (composite) is raised, making it less likely for problems such as sticking to the surface to occur. As a result, there is the advantage of improved productivity. Furthermore, when the polymer (C2) contains both reactive functional group-containing units and reactive functional group-free units, there is also the advantage that the dispersibility of the polymer (C1) is improved because the dispersibility of the modifier (C) (composite) is improved.

[0104] Specific examples of reactive functional group-containing units in polymer (C2) are the same as those described in the section on (reactive functional group-containing units) in the section on (polymer (C1)) above, so we will refer to that description and omit the explanation here. Preferred embodiments of reactive functional group-containing units in polymer (C1) are also preferred embodiments of reactive functional group-containing units in polymer (C2). Specific examples of reactive functional group-free units in polymer (C2) are the same as those described in the section on (reactive functional group-free units) in the section on (polymer (C1)) above, so we will refer to that description and omit the explanation here. Preferred embodiments of reactive functional group-free units in polymer (C1) are also preferred embodiments of reactive functional group-free units in polymer (C2).

[0105] The reactive functional group-containing units preferably include epoxy group-containing (meth)acrylate units, and more preferably include glycidyl methacrylate units. In other words, polymer (C2) preferably includes epoxy group-containing (meth)acrylate units, and more preferably includes glycidyl methacrylate units, as reactive functional group-containing units. This configuration has the advantage of compatibility between the modifier (C) and the polyester resin, and dispersibility of the modifier (C) during melt kneading. The reactive functional group-containing units in polymer (C2) may consist only of epoxy group-containing (meth)acrylate units, or only of glycidyl methacrylate units.

[0106] The polymer (C2) preferably contains 0.5% to 10.0% by weight of reactive functional group-containing units, more preferably 1.0% to 9.0% by weight, more preferably 1.5% to 9.5% by weight, more preferably 2.0% to 8.0% by weight, more preferably 2.5% to 7.5% by weight, more preferably 3.0% to 7.0% by weight, even more preferably 4.0% to 6.5% by weight, and particularly preferably 5.0% to 6.0% by weight. This configuration has the advantage of being able to obtain a resin composition with high melt viscosity.

[0107] The polymer (C2) preferably contains one or more constituent units selected from the group consisting of aromatic vinyl units and (meth)acrylic units. This configuration has the advantage that the modifier (C) has excellent compatibility with the crystalline polyester resin (A). The "aromatic vinyl units" include both constituent units derived from reactive functional group-containing aromatic vinyl compounds (e.g., 4-vinylbenzylglycidyl ether) and constituent units derived from reactive functional group-free aromatic vinyl compounds. The "(meth)acrylic units" include both constituent units derived from reactive functional group-containing (meth)acrylic monomers and constituent units derived from reactive functional group-free (meth)acrylic monomers. For specific examples of reactive functional group-containing (meth)acrylic monomers, the description in the (reactive functional group-containing units) section of the (polymer (C1)) section can be appropriately referenced. Specific examples of reactive functional group-free aromatic vinyl compounds and reactive functional group-free (meth)acrylic monomers are the same as those described in the (Reactive Functional Group-Free Units) section of the (Polymers (C1)) section above; therefore, that description is used as a reference and the explanation is omitted here.

[0108] From the viewpoint of obtaining a polyester resin composition with improved melt viscosity (IV value) by reaction between the crystalline polyester resin (A) and the modifier (C), and from the viewpoint of the modifier (C) having excellent compatibility with the crystalline polyester resin (A), the polymer (C2) more preferably contains (i) one or more constituent units selected from the group consisting of reactive functional group-free aromatic vinyl units and alkyl (meth)acrylic units, and may consist only of one or more units selected from the group, and (ii) styrene units, reactive functional group-containing (meth)acrylate units, reactive functional group-free methyl (meth)acrylate units, reactive functional group-free ethyl (meth)acrylate units, reactive functional group-free propyl (meth)acrylate units and reactive (iii) It is more preferable to include one or more structural units selected from the group consisting of functional group-free butyl (meth)acrylate units, and it may consist of only one or more selected from said group; (iv) It is more preferable to include one or more structural units selected from the group consisting of styrene units, glycidyl (meth)acrylate units, methyl (meth)acrylate units, ethyl (meth)acrylate units, and butyl (meth)acrylate units, and it may consist of only one or more selected from said group; (iv) It is more preferable to include one or more structural units selected from the group consisting of styrene units, glycidyl methacrylate units, methyl methacrylate units, and butyl acrylate units, and it may consist of only one or more selected from said group.

[0109] The total content of aromatic vinyl units in polymer (C2) is not particularly limited, but is preferably 10% to 95% by weight of polymer (C2) per 100% by weight. The upper limit of the content may be 95%, 90%, or 80% by weight, and the lower limit may be 15%, 20%, or 30% by weight. When the total content of aromatic vinyl units in polymer (C2) is within the above range, the modifier (C) has the advantage of having excellent compatibility with the crystalline polyester resin (A).

[0110] The total content of (meth)acrylic units in polymer (C2) is not particularly limited, but is preferably 10% to 70% by weight of polymer (C2) per 100% by weight. The upper limit of the content may be 60% by weight, 50% by weight, 40% by weight, or 30% by weight, and the lower limit may be 15% by weight or 20% by weight. When the total content of (meth)acrylic units in polymer (C2) is within the above range, the modifier (C) has the advantage of having excellent compatibility with the crystalline polyester resin (A).

[0111] The total content of aromatic vinyl units and (meth)acrylic units in polymer (C2) is not particularly limited, but is preferably 10% to 99% by weight per 100% by weight of polymer (C2). The upper limit of the content may be 95%, 90%, 80%, or 70% by weight, and the lower limit may be 15%, 20%, 30%, 40%, 50%, 60%, or 70% by weight. When the total content of aromatic vinyl units and (meth)acrylic units in polymer (C2) is within the above range, the modifier (C) has the advantage of having excellent compatibility with the crystalline polyester resin (A).

[0112] It is preferable that the number-average molecular weight of polymer (C2) is different from that of polymer (C1). More preferably, the number-average molecular weight of polymer (C2) is greater than that of polymer (C1). With this configuration, the softening point of the modifier (C) (composite) is raised, and problems such as sticking are less likely to occur. As a result, there is the advantage of improved productivity.

[0113] The number-average molecular weight of the polymer (C2) is preferably 80,000 Da to 300,000 Da, more preferably 90,000 Da to 200,000 Da, even more preferably 95,000 Da to 180,000 Da, and particularly preferably 100,000 Da to 150,000 Da. This configuration has the advantage that the modifier (C) has excellent reactivity with the crystalline polyester resin (A).

[0114] It is preferable that the number-average content of reactive functional groups in polymer (C2) differs from the number-average content of reactive functional groups in polymer (C1). It is preferable that the number-average content of reactive functional groups in polymer (C2) is greater than the number-average content of reactive functional groups in polymer (C1). With this configuration, the modifier (C) can improve the viscosity of the crystalline polyester resin (A), that is, a polyester resin composition with excellent viscosity-increasing properties can be obtained. As a result, there is an advantage in that a polyester resin composition with a higher melt viscosity (IV value) can be obtained.

[0115] When the polymer (C2) contains reactive functional groups, it is preferable that the polymer (C2) has an average of 2 to 35 such reactive functional groups per polymer (C2) molecule, and more preferably 15 to 35. The lower limit of the number average content of reactive functional groups in the polymer (C2) may be 5 or more, 10 or more, 20 or more, or 25 or more, and the upper limit may be 33 or less. When the number average content of reactive functional groups in the polymer (C2) 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 recycled polyester resin fibers.

[0116] It is preferable that polymer (C2) is a non-rubber polymer. This configuration has the advantage that the reaction between the reactive functional groups of polymer (C2) and the terminal functional groups of the 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 (C1) is a non-rubber polymer or polymer (C2) is a non-rubber polymer, and it is more preferable that both polymer (C1) and polymer (C2) are non-rubber polymers (for example, the entire modifier (C) (composite) is a non-rubber polymer).

[0117] Polymer (C1) and polymer (C2) may differ in one or more aspects selected from the group consisting of the composition of constituent units, number-average molecular weight, and the number-average content of reactive functional groups per molecule.

[0118] In case A, the content ratio of polymer (C1) and polymer (C2) in the modifier (C) is not particularly limited. In case A, for example, from the viewpoint of raising the softening point of the modifier (C) (composite) and thereby improving the productivity of the modifier (C) (composite), it is preferable that the modifier (C) contains 15% to 70% by weight of polymer (C1) and 30% to 85% by weight of polymer (C2) per 100% by weight of the modifier (C), more preferably 20% to 70% by weight of polymer (C1) and 30% to 80% by weight of polymer (C2), even more preferably 30% to 60% by weight of polymer (C1) and 40% to 70% by weight of polymer (C2), and particularly preferably 40% to 50% by weight of polymer (C1) and 50% to 60% by weight of polymer (C2). Furthermore, in case A, for example, the production costs of the modifier (C) are such that the modifier (C) preferably contains 50% to 90% by weight of polymer (C1) and 10% to 50% by weight of polymer (C2) per 100% by weight of the modifier (C), more preferably contains 50% to 90% by weight of polymer (C1) and 10% to 50% by weight of polymer (C2), even more preferably contains 70% to 90% by weight of polymer (C1) and 10% to 30% by weight of polymer (C2), and particularly preferably contains 80% to 90% by weight of polymer (C1) and 10% to 20% by weight of polymer (C2).

[0119] (Method for producing polymer (C2)) The polymerization method for polymer (C2) can be any known method and is not particularly limited. For example, bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., can be used as the polymerization method for polymer (C2), but emulsion polymerization is preferred.

[0120] When producing polymer (C2), 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 polymer (C2) contains constituent units derived from the chain transfer agent.

[0121] Regarding polymer (C2), the information in section [polymer (C1)] may be applied as appropriate, except for the matters mentioned above.

[0122] The amount of modifier (C) used in this crystallization suppression method is not particularly limited, but is preferably 0.2 to 10.0 parts by weight, more preferably 0.4 to 8.0 parts by weight, more preferably 0.5 to 6.0 parts by weight, even more preferably 0.6 to 4.0 parts by weight, even more preferably 0.8 to 4.0 parts by weight, and particularly preferably 1.0 to 3.0 parts by weight, based on 100 parts by weight of the total amount of crystalline polyester resin (A) and amorphous polyester resin (B). This configuration has the advantage of being able to further improve the melt viscosity (IV value) of the resulting polyester resin composition.

[0123] [Other resins] In the mixing process, resins other than the crystalline polyester resin (A) and amorphous polyester resin (B) may or may not be further mixed. In this specification, "resins other than the crystalline polyester resin (A) and amorphous polyester resin (B)" may be referred to as "other resins." Other resins are not particularly limited, but examples include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, polytetrafluoroethylene, ABS resin, heat-resistant ABS resin, AS resin, heat-resistant AS resin, acrylic resin, polyacetal, polycarbonate, modified polyphenylene ether, polyamide, and cyclic polyolefin.

[0124] When other resins are further mixed in the mixing process, there are no particular limitations on the amount of other resins used in the mixing process. For example, the amount of other resins used in the mixing process may be 0 to 60 parts by weight per 100 parts by weight of the total amount of crystalline polyester resin (A) and amorphous polyester resin (B). The upper limit of the amount used may be 50 parts by weight or less, 40 parts by weight or less, 30 parts by weight or less, 20 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less.

[0125] [Other additives] In the mixing process, additives that can be incorporated into a general thermoplastic resin composition may be further mixed. Such 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, UV absorbers, antistatic agents, flow improvers, mold release agents, compatibilizers, and heat stabilizers.

[0126] [Mixing process] In the mixing step, at least a crystalline polyester resin (A) and an amorphous polyester resin (B) may be mixed. The mixing step may also be a step in which raw materials including at least a crystalline polyester resin (A) and an amorphous polyester resin (B), and optionally a modifier (C), other resins and / or other additives, are mixed.

[0127] For mixing the raw materials containing crystalline polyester resin (A) and amorphous polyester resin (B), known equipment such as a Henschel mixer or a tumbler mixer can be used.

[0128] A crystallization suppression method according to one embodiment of the present invention may further include a melt-kneading step in which the mixture obtained in the mixing step is melt-kneaded after the mixing step. 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 melt-kneading the mixture.

[0129] Alternatively, the mixing step may be a process of mixing and melt-kneading the raw materials, which include at least a crystalline polyester resin (A) and an amorphous polyester resin (B), using the kneader described above.

[0130] The resin composition obtained through the crystallization suppression method according to one embodiment of the present invention can be suitably used in injection molding and blow molding, and in particular suitably used in injection blow molding. The resin composition obtained through the crystallization suppression method according to one embodiment of the present invention can be subjected to various molding methods other than injection molding and blow molding (for example, extrusion molding, calendering, inflation molding, rotational molding, and press molding) to obtain various molded articles.

[0131] [3. Method for manufacturing injection-molded articles] A method for manufacturing an injection-molded article according to one embodiment of the present invention includes a step of injection molding a polyester resin composition obtained through the crystallization suppression method described in the section [2. Method for suppressing crystallization of polyester resin], i.e., a polyester resin composition according to one embodiment of the present invention. An injection-molded article obtained by the method for manufacturing an injection-molded article according to one embodiment of the present invention is also one embodiment of the present invention.

[0132] In the method for manufacturing an injection-molded article according to one embodiment of the present invention, a polyester resin composition according to one embodiment of the present invention, that is, a polyester resin composition in which the crystallization of the polyester resin is suppressed, is used. Therefore, the method for manufacturing an injection-molded article according to one embodiment of the present invention has the advantage of being able to provide an injection-molded article with excellent impact strength.

[0133] The specific embodiment of the process for injection molding the polyester resin composition is not particularly limited, and known injection molding methods can be applied. The injection-molded article obtained by the method for manufacturing an injection-molded article according to one embodiment of the present invention may be used as a preform for blow molding, as described later. In other words, the method for manufacturing an injection-molded article according to one embodiment of the present invention may be carried out as one step in the method for manufacturing a blow-molded article according to one embodiment of the present invention, as described later.

[0134] [4. Method for manufacturing blow-molded articles] A method for manufacturing a blow-molded article according to one embodiment of the present invention comprises: step 1 of injection molding a polyester resin composition obtained through the crystallization suppression method described in section [2. Method for suppressing crystallization of polyester resin] above; and step 2 of blow molding the injection-molded article obtained in step 1. A method for manufacturing a blow-molded article according to one embodiment of the present invention can also be called an injection blow molding method. A blow-molded article obtained by a method for manufacturing a blow-molded article according to one embodiment of the present invention is also one embodiment of the present invention.

[0135] In the method for manufacturing a blow-molded article according to one embodiment of the present invention, a polyester resin composition obtained through the crystallization suppression method described in section [2. Method for suppressing crystallization of polyester resin] is used. Therefore, even when a polyester resin that may contain impurities that can promote the crystallization of the resin, such as recycled polyester resin, is used as a raw material, it has the advantage that a blow-molded article can be provided.

[0136] The specific embodiment of step 1, in which the polyester resin composition is injected, is not particularly limited, and known injection molding methods can be applied. Similarly, the specific embodiment of step 2, in which the injection-molded article obtained in step 1 is blow-molded, is not particularly limited, and known blow molding methods can be applied.

[0137] [4.Applications] According to one embodiment of the present invention, a method can be provided that can suppress the crystallization of a polyester resin. According to the crystallization suppression method according to one embodiment of the present invention, a polyester resin composition in which the crystallization of the polyester resin is suppressed can be provided. By using the polyester resin composition obtained through the crystallization suppression method according to one embodiment of the present invention, blow molding (particularly the two-step blow molding method) can be easily carried out. Therefore, one embodiment of the present invention is not particularly limited, but 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, bearings, 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 container applications 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. [Examples]

[0138] The present invention will be described more specifically with reference to the following examples and comparative examples, but the present invention is not limited to these, and examples obtained by appropriately combining the technical means disclosed in each example are also included within the scope of the present invention.

[0139] [Measurement methods and evaluation methods] <Method for measuring volume-average particle diameter> The volume-average particle size of polymers or composites was measured using a Microtrac UPA (manufactured by Nikkiso Co., Ltd.) with latex containing the polymer or composite as a sample, and obtained using the method for calculating volume-average particle size.

[0140] <Method for measuring 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.

[0141] <Method for measuring number-average molecular weight> The number-average molecular weights of polymers (C1) and (C2) 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 Preliminary 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: 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 Sample pressure lower limit: 0.2 MPa Reference pressure limit: 12.0 MPa Reference pressure lower limit: 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 ratio: 1x Flow rate increase / decrease control: Disabled Flow rate increase rate: 0.35 mL / min / min Flow rate reduction rate: 0.35mL / min / 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 Peak detection conditions RI Detection sensitivity (front): 3,000 mV / min Detection sensitivity (rear side): 3,000 mV / min Base detection value: 1.000mV / min Exclusion area: 10.000mVs Exclusion height: 0.000mV Excluding half-width: 0.000s UV / EXT Detection sensitivity (front): 3,000 mV / min Detection sensitivity (rear side): 3,000 mV / min Base detection value: 1.000mV / min Exclusion area: 10.000mVs Exclusion height: 0.000mV Excluding half-width: 0.000s 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 (C1) and polymer (C2)) under the conditions described above, and the number-average molecular weight of each sample was calculated from the calibration curve.

[0142] <Method for measuring the amount of reactive functional groups per molecule (number average)> The number-average content of reactive functional groups per molecule was measured according to the JIS K7236:2001 standard. Specifically, the procedure was as follows: The accurately weighed polymer (C1) was dissolved in chloroform. Acetic acid and tetraethylammonium bromide acetic acid solution were added to the resulting solution, and the resulting solution was used as a sample for potentiometric titration with a 0.1 mol / L perchloric acid-acetic acid standard solution. As the perchloric acid-acetic acid standard solution was added, perchloric acid and tetraethylammonium bromide reacted to produce hydrogen bromide. The generated hydrogen bromide reacted with the reactive functional groups. The endpoint was reached when all reactive functional groups had reacted and hydrogen bromide was in excess. Using this method, the number-average content of reactive functional groups per molecule (per molecule) of polymer (C1) was measured (calculated). Furthermore, if the only reactive functional group-containing monomer used in the polymerization of polymer (C1) is an epoxy group-containing monomer, the amount of reactive functional groups per polymer molecule (number average) measured (calculated) by the method described above can be said to be the number of epoxy groups per polymer molecule (average number).

[0143] <Method for measuring crystallization temperature> The crystallization temperature of the resin compositions obtained in each example was measured by differential scanning calorimetry (DSC). Specifically, 10 mg of the resin composition was used as a sample, and a differential scanning calorimetry device was used to raise the device temperature from 30°C to 290°C at a heating rate of 10°C / min to obtain a DSC curve. One peak was observed in the obtained DSC curve. The peak temperature in the DSC curve was defined as the crystallization temperature of the resin composition. The results are shown in Table 1. There is a tendency for crystallization to be suppressed as the crystallization temperature increases.

[0144] <Method for evaluating the crystallization state> The films obtained in each example and comparative example were left in a 120°C constant temperature bath for 2 or 3 minutes, and then removed from the bath. Subsequently, the crystallization status of the removed films was visually inspected and evaluated according to the following criteria. The results are shown in Table 1. A (Good): The film is transparent. B (Pass): Part of the film (but not the entire film) is white (i.e., crystallized). C (Defective): The entire surface of the film is white (i.e., crystallized).

[0145] <Method for evaluating elongation (amount of elongation)> To evaluate the crystallization state of the resin composition from different angles, elongation tests were conducted during heating (at high temperatures). The specific evaluation method was as follows: Two lines (gauge marks) were marked at 40 mm intervals along the length of the film obtained in each example and comparative example. That is, the distance between the gauge marks on the film was 40 mm. Next, a 20 g weight was suspended from the film with the gauge marks, and the film was left in a constant temperature bath at 120°C or 130°C for 3 minutes. After that, the film was removed from the constant temperature bath. Then, the distance between the gauge marks on the removed film was measured, and the elongation amount (mm) from 40 mm (= distance between gauge marks on the film after being left in the constant temperature bath (mm) - 40 mm) was calculated. The results are shown in Table 1. Note that a larger elongation amount indicates that the crystallization of the resin composition is suppressed. Furthermore, a larger elongation amount suggests that the injection molded article (preform) will be more easily stretched in injection blow molding. Therefore, a larger elongation amount can be said to be a superior result. In Example 4, the film stretched and broke (cut) after being left in a 130°C constant temperature bath for 3 minutes. Therefore, it was labeled "cut" in Table 1.

[0146] [material] <Polyester resin (A)> Polyester resin (A1): A pellet-shaped recycled polyester resin obtained by recycling PET film used and discarded during the manufacture of MLCCs (ceramic capacitors). Polyester resin (A2): Recycled polyester resin obtained by recycling PET bottle preforms. Both polyester resins (A1) and (A2) are polyethylene terephthalate (PET). <Amorphous polyester resin (B)> Amorphous polyester resin (B): GN001, manufactured by Eastman Chemical Company. <Modifier (C)> Modifier (C): The modifier obtained in the following manufacturing example 1 was used.

[0147] <Manufacturing Example 1: Preparation of Modifier> (Preparation of polymer (C1)) First, purified water (180 parts by weight), sodium formaldehyde sulfoxylate (1.5 parts by weight), ethylenediaminetetraacetic acid (EDTA) (0.0075 parts by weight), ferrous sulfate heptahydrate (0.3 parts by weight), and t-butyl hydroperoxide (0.1 parts by weight) were added to the reactor.

[0148] Subsequently, the temperature inside the reactor was raised to 75°C while stirring the raw materials, and nitrogen was bubbled into the raw materials inside the reactor for 30 minutes.

[0149] Next, a monomer mixture consisting of styrene (ST) (70 parts by weight), a monomer without reactive functional groups, glycidyl methacrylate (GMA) (10 parts by weight), a monomer containing reactive functional groups, and n-octyl mercaptan (1.5 parts by weight), a chain transfer agent, was added to the reactor over 150 minutes. Furthermore, t-butyl hydroperoxide (0.1 parts by weight) was added to the reactor sequentially at the same time as the addition of the monomer mixture. The mixture in the reactor was then reacted until the polymerization conversion rate reached 90% or more. After the polymerization conversion rate reached 90%, the mixture in the reactor was reacted for a further 30 minutes. Polymer (C1) was obtained by this operation.

[0150] (Preparation of polymer (C2) and modifier) Next, a monomer mixture consisting of butyl acrylate (5 parts by weight), GMA (1 part by weight), and ST (14 parts by weight) was added to the reactor containing the polymer (C1). During the addition of the monomer mixture, sodium ethoxyalkylated alkyl phosphate (0.2 parts by weight) and t-butyl hydroperoxide (0.03 parts by weight) were added to the reactor as needed.

[0151] Next, the mixture in the reactor was reacted until the polymerization conversion rate reached 98% or higher to obtain polymer (C2). As a result, a latex containing a modifier, which was a composite of polymer (C1) and polymer (C2), was obtained. Polymer (C2) contained 5% by weight of GMA units as reactive functional group-containing units per 100% by weight of polymer (C2).

[0152] Using the method described above, the volume-average particle size of the modifier in the latex was measured to be 1100 angstroms. Furthermore, it can be considered that polymer (C1) forms the core portion and polymer (C2) forms the shell portion in the modifier. In other words, the modifier can be considered to have a core-shell structure. The modifier contained 80% by weight of polymer (C1) and 20% by weight of polymer (C2) per 100% by weight of the modifier. The number-average molecular weight of the modifier was measured using the method described above. As a result, the modifier had two different number-average molecular weights (Mn): the number-average molecular weight of polymer (C1) was 7,000 Da, and the number-average molecular weight of polymer (C2) was 12,000 Da. As measured using the method described above, the average number of reactive functional groups (epoxy groups) per molecule of polymer (C1) was 9.

[0153] To recover the modifier as a powder from the latex, the latex was quickly added to a 5% calcium chloride aqueous solution while stirring the solution. The resulting mixture was heated to 70°C using steam heating and maintained at that temperature. Next, the temperature of the mixture was raised to 85°C to form aggregates of the modifier in the mixture, and then the mixture was dehydrated to obtain the aggregates of the modifier. The obtained aggregates of the modifier were dried to obtain modifier powder. Subsequently, the modifier powder was sieved through an 18-mesh screen to obtain the white powder that passed through the 18-mesh screen. The obtained white powder was used as "modifier (C)".

[0154] <Examples 1-4> (1) Resin composition The polyester resin (A), amorphous polyester resin (B), and modifier (C) in the amounts listed in Table 1 were mixed in a tumbler mixer to obtain a mixture (mixing step).

[0155] The resulting mixture was subjected to a 25 mm twin-screw extruder and melt-kneaded under the following conditions to obtain a resin composition. The resulting resin composition was alloyed and in pellet form. Extrusion conditions: Temperature; C1 / C2 / C3 / C4 / C5 / C6 / C7 / D = 100℃ / 245℃ / 245℃ / 245℃ / 245℃ / 245℃ / 250℃ / 250℃ (C stands for cylinder, D stands for die) Screw rotation speed: 250 rpm, Discharge amount: 15kg / hour.

[0156] The crystallization temperature of the obtained resin composition was measured using the method described above. The results are shown in Table 1.

[0157] (2) Film Using a resin composition as a sample, a film with a width of 35 mm and a thickness of 0.15 mm was prepared under the following conditions using a laboratory conical extruder manufactured by Toyo Seiki Co., Ltd. equipped with a T-die. conditions: Temperature; C1 / C2 / C3 / D=250℃ / 250℃ / 260℃ / 270℃ Screw rotation speed: 50 rpm Discharge amount: 2kg / hour.

[0158] The resulting films were evaluated for their crystallization state and swelling during the blowing process using the method described above. The results are shown in Table 1.

[0159] (3) Injection blow molding Injection blow molding was attempted for the resin compositions of Examples 3 and 4. Specifically, the procedure was as follows: (i) Each resin composition of Examples 3 and 4 was used as a sample and injection molded using an injection molding machine to obtain injection molded articles (preforms) (Step 1); (2) Using a blow molding machine, the obtained preforms were reheated and then air was blown into the preforms (i.e., blow molding was performed) (Step 2). When the preforms obtained in Step 1 were visually inspected for the presence or absence of crystallization, no crystallization was observed. Therefore, "None" was written in the "Presence or Absence of Crystallization of Preform" column of Table 1. Furthermore, when it was checked whether the preforms expanded when air was blown into them, expansion of the preforms was observed. In other words, it was confirmed that blow molding was possible. Therefore, "Possible" was written in the "Injection Blow Molding" column of Table 1 to indicate that blow molding was possible.

[0160] <Comparative Example 1> The crystallization temperature of the polyester resin (A1) was measured using the same method as described in <Method for Measuring Crystallization Temperature>, except that the polyester resin (A1) itself was used as the sample instead of the resin composition obtained in the examples. The results are shown in Table 1.

[0161] Except for using a polyester resin (A1) as the sample instead of the resin composition obtained in the examples, the film was prepared using the same method and conditions as described in section (2) "Film". The crystallization state and swelling during the blowing process of the obtained film were evaluated using the method described above. The results are shown in Table 1.

[0162] Except for using a polyester resin (A1) as the sample instead of the resin composition, injection blow molding was attempted using the same method as described in section (3) "Injection Blow Molding". When the preform obtained in step 1 was visually inspected for the presence or absence of crystallization, it was confirmed that crystallization had occurred. Therefore, "Yes" was written in the "Presence or Absence of Crystallization of Preform" column of Table 1. Furthermore, when it was checked whether the preform would expand when air was blown into it, no expansion of the preform was observed. In other words, it was confirmed that blow molding was impossible. Therefore, "Impossible" was written in the "Injection Blow Molding" column of Table 1 to indicate that blow molding was impossible.

[0163] <Comparative Example 2> The crystallization temperature of the polyester resin (A2) was measured using the same method as described in <Method for Measuring Crystallization Temperature>, except that the polyester resin (A2) itself was used as the sample instead of the resin composition obtained in the examples. The results are shown in Table 1.

[0164] Except for using a polyester resin (A2) as the sample instead of the resin composition obtained in the examples, the film was prepared using the same method and conditions as described in section (2) "Film". The crystallization state and swelling during the blowing process of the obtained film were evaluated using the method described above. The results are shown in Table 1.

[0165] [Table 1] [Industrial applicability]

[0166] According to one embodiment of the present invention, a method can be provided that can suppress the crystallization of polyester resins. 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; in 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; in mechanical applications such as hydraulic and pneumatic connectors and tubes, bearings, covers and housings, bearings, pressure-resistant hoses, and cable ties; in building materials applications such as curtain rail components, aluminum sash corners, door rollers, handrails, curtain rollers, and door handles; in sports and leisure applications such as sports shoe soles, ski and snowboard equipment, reels, and diving snorkels; in packaging materials and container applications such as shrink wrapping film, food packaging film, alcoholic beverage bottles, beverage bottles, and pesticide bottles; and in medical applications such as toothbrushes, chair legs and armrests, and sutures.

Claims

1. A method for suppressing crystallization of a polyester resin, comprising a mixing step of mixing a crystalline polyester resin (A) and an amorphous polyester resin (B).

2. In the aforementioned mixing step, the modifier (C) is further mixed, The method for suppressing crystallization of a polyester resin according to claim 1, wherein the modifier (C) comprises a polymer (C1) containing reactive functional group-containing units and reactive functional group-free units.

3. The modifier (C) further comprises a polymer (C2) containing a reactive functional group-containing unit, The method for suppressing crystallization of a polyester resin according to claim 2, wherein the content of polymer (C1) and polymer (C2) in the modifier (C) is 50% to 90% by weight of polymer (C1) and 10% to 50% by weight of polymer (C2) in 100% of the modifier (C).

4. The method for suppressing the crystallization of a polyester resin according to claim 1, wherein the amount of amorphous polyester resin (B) used in the method for suppressing the crystallization of the polyester resin is 5% to 60% by weight of the total amount of crystalline polyester resin (A) and amorphous polyester resin (B) used, which is 100% by weight.

5. The method for suppressing crystallization of a polyester resin according to claim 1, wherein the amorphous polyester resin (B) contains glycol-modified polyethylene terephthalate.

6. The method for suppressing crystallization of a polyester resin according to claim 1, wherein the crystalline polyester resin (A) includes a recycled polyester resin.

7. The method for suppressing crystallization of a polyester resin according to claim 3, wherein the content of the reactive functional group-containing unit in the polymer (C2) is 0.5% by weight to 10.0% by weight of 100% by weight of the polymer (C2).

8. The method for suppressing crystallization of a polyester resin according to claim 3, wherein the reactive functional group-containing unit in the polymer (C2) includes an epoxy group-containing (meth)acrylate unit.

9. The method for suppressing crystallization of a polyester resin according to claim 3, wherein the polymer (C2) further comprises aromatic vinyl units and / or (meth)acrylic units as constituent units.

10. The method for suppressing crystallization of a polyester resin according to claim 2, wherein the polymer (C1) has an average of 2 to 10 reactive functional groups per molecule.

11. The method for suppressing crystallization of a polyester resin according to claim 2, wherein the number average molecular weight of the polymer (C1) is 2,000 Da to 10,000 Da.

12. The polymer (C1) is (i) The reactive functional group-containing unit includes an epoxy group-containing (meth)acrylate unit, (ii) The method for suppressing crystallization of a polyester resin according to claim 2, wherein the reactive functional group-free unit includes one or more constituent units selected from the group consisting of reactive functional group-free aromatic vinyl units and reactive functional group-free (meth)acrylate units.

13. The method for suppressing the crystallization of a polyester resin according to claim 2, wherein the amount of the modifier (C) used in the method for suppressing the crystallization of the polyester resin is 0.2 parts by weight to 10.0 parts by weight with respect to 100 parts by weight of the total amount of the crystalline polyester resin (A) and the amorphous polyester resin (B) used.

14. The method for suppressing crystallization of a polyester resin according to claim 1, wherein the crystalline polyester resin (A) comprises one or more selected from the group consisting of polyethylene terephthalate and polybutylene terephthalate.

15. A method for producing an injection-molded article, comprising the step of injection molding a polyester resin composition obtained through a method for suppressing the crystallization of a polyester resin according to any one of claims 1 to 14.

16. Step 1 involves injection molding a polyester resin composition obtained through a method for suppressing crystallization of a polyester resin according to any one of claims 1 to 14, A method for manufacturing a blow-molded article, comprising step 2 of blow-molding the injection-molded article obtained in step 1.

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