Masterbatch, resin composition and resin molded body

Abstract

The masterbatch provided by this invention is a resin composition that, when diluted with polyester resin, yields a resin composition with good processability and formability, good transparency, and low yellowness. The masterbatch of this invention contains: amorphous PET (A), and a chain elongator (B) with a weight-average epoxy functional group number of 3 or more and 65 or less, and a weight-average molecular weight of 2000 to 30000. The content of the chain elongator (B) in the masterbatch is 5 to 30% by mass. Furthermore, when the intrinsic viscosity of a resin composition sample obtained by melt-blending crystalline PET (with an intrinsic viscosity IVa of 0.9 to 1.0 dL / g after melt-blending alone) with the masterbatch at a chain elongator (B) content of 0.4% by mass is set to IVb (dL / g), 0 < IVb - IVa < 0.29. Moreover, this masterbatch is used in combination with polyester resin under the condition that the content of the chain elongator (B) in the resin composition is 0.01 to 1.0% by mass.

Description

[Technical Field]

[0001] This invention relates to masterbatch, resin composition, and resin molded body. [Previous Technology]

[0002] Polyester resin is currently used in various fields such as PET bottles, sheets, films, and fibers. For example, the widespread use of PET bottles, primarily for beverages, has attracted much attention in recent years, and their usage has become enormous. Japan uses colorless and transparent PET bottles to promote recycling. In recent years, for mass-produced and consumed goods, the social demand for recycling and reusing post-consumer waste has increased, rather than simply discarding it. Under these circumstances, recycling and regeneration of PET bottles is being promoted in particular.

[0003] There are various methods for recycling PET bottles. Material recycling includes horizontal recycling and cascade recycling. Horizontal recycling involves collecting used PET bottles, crushing and washing them to produce recycled polyethylene terephthalate (PET) sheets, which are then used as raw materials to remanufacture PET bottles. On the other hand, cascade recycling involves using the recycled PET sheets for products such as films or fibers, where the required performance is lower than that of PET bottles. In any case, each time recycling is repeated, the PET becomes low in molecular weight due to heat and other factors, resulting in deterioration in formability and strength. Therefore, the number of times recycling can be performed is limited.

[0004] As one method for obtaining improved quality products from low-molecular-weight recycled polyethylene terephthalate (PET) sheets, a method is proposed that involves incorporating an effective chain-extending agent into a polyester resin and then performing melt mixing. For example, Patent Document 1 discloses a modifier for crystalline polyester resin, comprising: an amorphous polyester resin; and a reactive compound containing two or more epoxypropyl and / or isocyanate groups per molecule, with a weight average molecular weight of 200 or more and 500,000 or less. According to this modifier, improvements in formability, particularly in the mechanical properties of PET sheets recycled from used polyethylene terephthalate bottles, can be achieved during melt molding using crystalline polyester resins, as well as improvements in maintaining transparency.

[0005] Furthermore, Patent Document 2 discloses a masterbatch for chain extension of polyester resin, comprising: a predetermined polyester resin (A), an epoxy-containing resin (B) with a weight average molecular weight of 6,000 to 200,000, and a chain-extended polyester resin (C) which is a reactant of polyester resin (A) and resin (B). According to Patent Document 2, the content of resin (B) and chain-extended polyester resin (C) in the masterbatch is set within a predetermined range, and the epoxy value of resin (B) is set within a predetermined range. This provides a method for manufacturing polyester resin molded articles with excellent processability and improved quality of molded articles using general processing methods, as well as a masterbatch used in this manufacturing method. [Prior Art Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2006-45477 [Patent Document 2] International Publication No. 2023 / 153522 [Summary of the Invention]

[0007] (Problem to be Solved by the Invention) However, in the technologies disclosed in the aforementioned Patent Documents 1 and 2, the transparency of the molded article can be understood as improving or maintaining transparency by utilizing the types and ratios of monomeric components such as the glycol (ethylene glycol) component constituting the polyester resin used. There is a desire for a technology that, in the form of a modifier or chain-extending masterbatch, can obtain a resin composition with good transparency by mixing it with a polyester resin that is the object of modification or chain extension.

[0008] Therefore, the present invention provides a masterbatch for use with polyester resin, which, when diluted with polyester resin, yields a resin composition with good processability and formability, good transparency, and low yellowness. (Technical means to solve the problem)

[0009] That is, the masterbatch provided by the present invention is a masterbatch for polyester resin, wherein it contains: amorphous polyethylene terephthalate (A); and a chain elongating agent (B) with a weight average number of epoxy functional groups of 3 or more and 65 or less and a weight average molecular weight of 2000 or more and 30000 or less, and satisfies the following conditions (1) to (3): Condition (1): The content of the chain elongating agent (B) in the masterbatch is 5% by mass or more and 30% by mass or less based on the total mass of the masterbatch; Condition (2): When the intrinsic viscosity of the resin composition sample obtained by melt-blending a crystalline polyethylene terephthalate with an intrinsic viscosity IVa of 0.9 dL / g or more and 1.0 dL / g or less after melt blending alone with the masterbatch, and the chain elongating agent (B) is 0.4% by mass, is set as IVb (dL / g), 0 < IVb - IVa < 0.29; Condition (3): The masterbatch is used in combination with the polyester resin under the condition that the chain elongating agent (B) in the resin composition containing the masterbatch and the polyester resin is 0.01% by mass or more and 1.0% by mass or less. (Effects compared to prior art)

[0010] According to the present invention, a masterbatch can be provided that, when diluted with polyester resin, yields a resin composition with good processability and formability, good transparency, and low yellowness.

Implementation Method

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

[0012] <Masterbatch> The masterbatch of one embodiment of the present invention (hereinafter sometimes simply referred to as "masterbatch") is a masterbatch for polyester resin. In the present invention, the polyester resin to which the masterbatch is used is sometimes referred to as "polyester resin (C)". Furthermore, since the masterbatch contains amorphous polyethylene terephthalate (A), it is a type of resin composition. For convenience, in the present invention, the composition obtained by mixing the masterbatch and polyester resin (C) using melt mixing or the like, and the composition compared with it, are referred to as "resin composition". Furthermore, in the present invention, the molded body obtained by molding the resin composition using injection molding or the like is referred to as "resin molded body".

[0013] The masterbatch contains amorphous polyethylene terephthalate (A) and chain elongator (B). The chain elongator (B) has a weight average number of epoxy functional groups of 3 or more and 65 or less, and a weight average molecular weight of 2,000 or more and 30,000 or less. Moreover, the masterbatch meets the following conditions (1) to (3).

[0014] Condition (1): The content of the chain elongating agent (B) in the masterbatch is 5% by mass or more and 30% by mass or less, based on the total mass of the masterbatch.

[0015] Condition (2): When the intrinsic viscosity of the resin composition sample obtained by melt-blending a crystalline polyethylene terephthalate with an intrinsic viscosity IVa of 0.9 dL / g or more and 1.0 dL / g or less after melt-blending alone with a masterbatch, and the content of chain elongating agent (B) is 0.4% by mass, is set as IVb (dL / g), 0 < IVb - IVa < 0.29.

[0016] Condition (3): The masterbatch is used in combination with polyester resin (C) under the condition that the content of chain elongating agent (B) in the resin composition containing masterbatch and polyester resin (C) is 0.01% by mass or more and 1.0% by mass or less.

[0017] By using a masterbatch containing amorphous polyethylene terephthalate (A) and the aforementioned specific chain elongating agent (B), and satisfying all conditions (1) to (3), the target resin composition can be obtained. That is, when the masterbatch is diluted with polyester resin (C), a resin composition with good processability and formability, and which is not prone to whitening, has good transparency, and low yellowness can be obtained.

[0018] The following is a detailed description of the components and conditions (1) to (3) of the masterbatch.

[0019] (Amorphous Polyethylene Terephthalate (A)) The masterbatch contains amorphous polyethylene terephthalate (A) (hereinafter sometimes referred to as "amorphous PET (A)"). Amorphous PET (A) is the matrix resin in the masterbatch. By using amorphous PET (A) as the matrix resin in the masterbatch, the crystallization temperature of the polyester resin (C) can be lowered when the masterbatch is diluted with polyester resin (C). This helps to provide a resin composition with good processability, formability, and transparency.

[0020] On the other hand, if crystalline polyethylene terephthalate (hereinafter sometimes referred to as "crystalline PET") is used instead of amorphous PET (A) as the matrix resin of the masterbatch, it will be more difficult to manufacture the masterbatch. The reason is that the processing temperature of crystalline PET is higher than that of amorphous PET, and the crosslinking reaction between crystalline PET and chain elongating agent (B) will be promoted during the masterbatch manufacturing stage, which may result in gelation.

[0021] Polyethylene terephthalate (PET) can be synthesized through the dehydration condensation of ethylene glycol and terephthalic acid, or the transesterification reaction of ethylene glycol and dimethyl terephthalate. Amorphous PET (A) is polyethylene terephthalate (PET) without a crystallization temperature, and is referred to as "A-PET" (abbreviation for amorphous polyethylene terephthalate) or "PET-G" (abbreviation for glycol-modified polyethylene terephthalate). PET-G is an amorphous PET in which a portion (e.g., 30-40 moles) of the ethylene glycol units in PET is replaced by cyclohexanediol units.

[0022] Among amorphous PET (A), ethylene glycol-modified polyethylene terephthalate (PET-G) is preferred. By using PET-G, the crystallization temperature of the polyester resin (C), which is a diluent resin, can be lowered more easily, thus helping to provide a resin composition with better processability, formability and transparency.

[0023] Regarding the crystallinity and amorphousness of thermoplastic resins, the determination is made in differential scanning calorimetry (DSC) by heating the thermoplastic resin from 30°C to 300°C at a rate of 10°C / min until it melts, and then cooling it back to 30°C at a rate of 10°C / min until it solidifies. The presence or absence of a heating peak associated with crystallization is used for this determination. Specifically, if such a heating peak is observed, the thermoplastic resin is considered crystalline. Conversely, if no heating peak is observed, the thermoplastic resin is considered amorphous. Therefore, the amorphous PET(A) described above can be an amorphous PET(A) that, when heated from 30°C to 300°C at a rate of 10°C / min until it melts, and then cooled back to 30°C at a rate of 10°C / min until it solidifies, does not exhibit a heating peak associated with crystallization. The observation of the heating peak is performed using a differential scanning calorimeter (DSC).

[0024] Commercially available amorphous PET(A) may also be used. Examples of commercially available amorphous PET(A) include the "EASTAR" series manufactured by Eastman Chemical Co., Ltd., and the "SKYGREEN" series manufactured by SK Chemicals Co., Ltd. Amorphous PET(A) may be used alone or in combination with two or more types.

[0025] The content of amorphous PET(A) in the masterbatch, based on the total mass of the masterbatch, is preferably 70% by mass or more and 95% by mass or less, more preferably 72% by mass or more and 92% by mass or less, and even more preferably 75% by mass or more and 90% by mass or less. By having the content of amorphous PET(A) in the masterbatch within the above range, when the masterbatch is diluted with polyester resin (C), a resin composition with better processability, formability, and transparency, and lower yellowness can be easily obtained.

[0026] (Chain elongating agent (B)) The masterbatch contains a chain elongating agent (B). This chain elongating agent (B) has a weight-average number of epoxy functional groups of 3 or more and 65 or less, and a weight-average molecular weight of 2000 or more and 30000 or less. Because the chain elongating agent (B) has a weight-average number of epoxy functional groups of 3 or more and 65 or less, it possesses epoxypropyl groups (epoxy groups). The epoxypropyl groups of the chain elongating agent (B) can react with at least one of the hydroxyl and carboxyl groups (hereinafter sometimes referred to as "hydroxyl and / or carboxyl groups") present in the polyester resin (C). Therefore, when the masterbatch is diluted with polyester resin (C), the chain elongating agent (B) can react with the polyester resin (C) to elongate the polyester resin (C) chains and increase its molecular weight, thereby suppressing yellowing and turbidity while also suppressing deformation during molding.

[0027] The weight-average number of epoxy functional groups and the weight-average molecular weight of the chain extender (B) must both be within the specific ranges mentioned above. The weight-average number of epoxy functional groups of the chain extender (B) is 3 or more and 65 or less, and the weight-average molecular weight of the chain extender (B) is preferably 4,000 or more and 20,000 or less, and more preferably 7,000 or more and 12,000 or less.

[0028] Assuming the weight average number of epoxy functional groups of the chain elongator (B) is 3 or more and 65 or less or more than 65, and the weight average molecular weight is less than 2000, excessive cross-linking reaction is likely to occur between the chain elongator (B) and the polyester resin (C) in the masterbatch. Therefore, the resin composition obtained by diluting with polyester resin (C) will whiten and its transparency will easily deteriorate. Furthermore, when the masterbatch and polyester resin (C) are melt-mixed, the viscosity increases, and the chain elongator (B) may become insufficiently dispersed in the polyester resin (C). On the other hand, assuming the weight average number of epoxy functional groups of the chain elongator (B) is 3 or more and 65 or less or less than 3, and the weight average molecular weight exceeds 30000, it is difficult to fully initiate the above-mentioned cross-linking reaction, and therefore the resulting resin composition will have poor formability. Furthermore, if the weight-average number of epoxy functional groups of the chain elongator (B) is less than 3 and the weight-average molecular weight is less than 2000, the aforementioned crosslinking reaction becomes insufficient, resulting in poor processability and moldability of the obtained resin composition. On the other hand, if the weight-average number of epoxy functional groups of the chain elongator (B) exceeds 65 and the weight-average molecular weight exceeds 30000, the aforementioned crosslinking reaction is more likely to be over-initiated, thus causing the resin composition obtained by diluting with polyester resin (C) to whiten and its transparency to easily deteriorate.

[0029] In this invention, the weight-average molecular weight of the chain extender (B) refers to the polystyrene conversion value determined using a gel permeation chromatography (GPC) analyzer. Specifically, the weight-average molecular weight of the chain extender (B) can be set as the value determined using the following apparatus and conditions: • GPC apparatus: Trade name "HLC-8020" (manufactured by Tosoh Corporation) • Column: Trade names "TSKgel G2000HXL", "G3000HXL", "G4000GXL" (manufactured by Tosoh Corporation) • Solvent: Tetrahydrofuran (THF) • Flow rate: 1.0 mL / min • Sample concentration: 2 g / L • Injection volume: 100 μL • Temperature: 40°C • Detector: Model "RI-8020" (manufactured by Tosoh Corporation) • Standard material: TSK standard polystyrene (manufactured by Tosoh Corporation)

[0030] The chain elongating agent (B) is as described above, having epoxypropyl (epoxy) groups as functional groups that can react with the hydroxyl and / or carboxyl groups of the polyester resin (C). The average number of epoxypropyl (epoxy) groups per molecule of the chain elongating agent (B) is expressed as a weight-average number of epoxy functional groups, which can be appropriately set according to the required reaction strength. The weight-average number of epoxy functional groups can be obtained from the weight-average molecular weight of the chain elongating agent (B) / epoxy equivalent. For example, by determining the target weight-average molecular weight, polymerization is carried out by adjusting the ratio of polymerizable monomers having epoxypropyl (epoxy) groups to other polymerizable monomers. In this way, a chain elongating agent (B) having the desired average number of epoxypropyl (epoxy) groups per molecule can be manufactured.

[0031] An example is given of a chain elongating agent (B) manufactured using glycidyl methacrylate as a polymerizable monomer containing glycidyl groups and styrene as another polymerizable monomer. Specifically, when using styrene and glycidyl methacrylate to manufacture a chain elongating agent (B) with a weight average molecular weight of 5000 and an average number of 4 glycidyl groups (epoxy groups) per molecule, the following is described. Styrene (molecular weight 104.15) and glycidyl methacrylate (molecular weight 142.15) are filled at a styrene:glycidyl methacrylate = 10.6:1 (mass ratio) to obtain a styrene / glycidyl methacrylate copolymer as the target chain elongating agent (B).

[0032] The weight-average number of epoxy functional groups in the chain elongator (B) is 3 or more and 65 or less, preferably 4 or more and 50 or less. Due to the effect of the chain elongator (B), when the masterbatch and polyester resin (C) are melt-blended, the hydroxyl and / or carboxyl groups of the polyester resin (C) react with the chain elongator (B), and some of them undergo crosslinking. This improves the strength during melt blending, making it easier to obtain a resin composition with good formability.

[0033] Assuming that the weight average molecular weight of the chain elongator (B) is more than 2000 and less than 30000 or more than 30000, and the weight average epoxy functional base is less than 3, the cross-linking points between the chain elongator (B) and the polyester resin (C) in the masterbatch become fewer. Therefore, the strength improvement during melt mixing of the masterbatch and polyester resin (C) becomes inadequate, which will have a reduction in the formability of the obtained resin composition. On the other hand, assuming that the weight average molecular weight of the chain elongator (B) is above 2000 and less than 30000 or less than 2000, and the weight average epoxy functional base exceeds 65, the excessive cross-linking points mentioned above facilitate the reaction of chain elongator (B) and polyester resin (C). Therefore, there will be a case of bleaching of the obtained resin composition, poor transparency, and again, there will be excessive reaction with polyester resin (C) and poor formability of the obtained resin composition. Also, assuming that the weight-average molecular weight of the chain elongator (B) is less than 2000 and the weight-average epoxy functional base is less than 3, the above cross-linking reaction becomes inadequate, resulting in poor processability and formability of the obtained resin composition. On the other hand, assuming that the weight-average molecular weight of the chain elongator (B) exceeds 30 000 and the weight-average epoxy functional basis exceeds 65, it is more likely to over-initiate the above cross-linking reaction, so the resin composition obtained by dilution of polyester resin (C) is whitened and the transparency is easily deteriorated.

[0034] The epoxy equivalent of the chain elongator (B) is preferably more than 100 g / mol and less than 1000 g / mol, more preferably more than 150 g / mol and less than 800 g / mol, and more preferably more than 200 g / mol and less than 600 g / mol. If the epoxy equivalent of the chain elongator (B) is more than 100g / mol, the above cross-linking points will increase moderately, the strength of the masterbatch and polyester resin (C) during melt mixing is easily improved, and the formability of the obtained resin composition can easily become good. On the other hand, if the epoxy equivalent of the chain elongator (B) is less than 1000g / mol, then the above cross-linking points are inhibited in an appropriate amount and the transparency of the obtained resin composition can easily become good. In the present invention, the epoxy equivalent of the chain elongator (B) may adopt a value determined according to the provisions of JIS K7236.

[0035] The chain elongating agent (B) may have epoxypropyl groups (epoxy groups) at any or multiple locations in the main chain, side chain, and terminal chain of the molecular chain. There are no particular limitations on the type of chain elongating agent (B) as long as the weight-average number of epoxy functional groups and the weight-average molecular weight are within the aforementioned specific ranges. A preferred chain elongating agent (B) is, as mentioned above, a copolymer containing a polymerizable monomer having epoxypropyl groups (epoxy groups) and other polymerizable monomers. This copolymer may be any of a random copolymer, block copolymer, graft copolymer, or cross copolymer.

[0036] Preferred examples of polymerizable monomers having an epoxypropyl group include: (meth)acrylate monomers having an epoxypropyl group (hereinafter sometimes referred to as "(meth)acrylate epoxypropyl ester monomers"). Examples of (meth)acrylate epoxypropyl ester monomers include: epoxypropyl acrylate, epoxypropyl methacrylate, 4-hydroxybutyl acrylate epoxypropyl ether, and allyl epoxypropyl ether. One or more of these may be used. Among these, epoxypropyl acrylate and epoxypropyl methacrylate are preferred. In this invention, the term "(meth)acrylate" is intended to encompass both "acrylate" and "methacrylate".

[0037] Preferred examples of other polymerizable monomers include: styrene monomers, (meth)acrylate monomers, and olefin monomers. Examples of styrene monomers include: styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, and p-tert-butylstyrene. One or more of the styrene monomers may be used. Examples of (meth)acrylate monomers include: methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and ethylhexyl (meth)acrylate. One or more of the (meth)acrylate monomers may be used. Examples of olefin monomers include: ethylene, propylene, butadiene, and isoprene. One or more olefin monomers may be used.

[0038] As a type of chain elongating agent (B), the preferred types are copolymers of styrene monomers and (meth)acrylate monomers (styrene / (meth)acrylate copolymers), copolymers of styrene monomers with (meth)acrylate monomers and (meth)acrylate monomers (styrene / (meth)acrylate / (meth)acrylate copolymers), and copolymers of styrene monomers with olefin monomers and (meth)acrylate monomers (styrene / olefin / (meth)acrylate copolymers).

[0039] Commercially available products can also be used as chain elongating agents (B). Examples of commercially available chain elongating agents (B) include: BASF's "Joncryl" ADR series, Toa Synthetic's "ARUFON" series, Nippon Oil's "MARPROOF" series, Sumitomo Chemical's "BONDFAST" series, and SK Chemicals' "LOTADER" series. One type of chain elongating agent (B) can be used alone, or two or more can be used in combination.

[0040] [Condition (1)] The masterbatch satisfies the above condition (1) regarding the content of chain elongating agent (B) in the masterbatch. That is, the content of chain elongating agent (B) in the masterbatch, based on the total mass of the masterbatch, is 5% by mass or more and 30% by mass or less. The content of chain elongating agent (B) in the masterbatch, based on the total mass of the masterbatch, is preferably 8% by mass or more and 28% by mass or less, and more preferably 10% by mass or more and 25% by mass or less. By having the content of chain elongating agent (B) in the masterbatch within the above range, when the masterbatch is diluted with polyester resin (C), a resin composition with better processability, formability and transparency can be easily obtained.

[0041] If the content of chain elongating agent (B) in the masterbatch is less than 5% by mass, the masterbatch is prone to gelation when amorphous PET (A) and chain elongating agent (B) are melt-blended to produce the masterbatch, making the production of the masterbatch difficult. Furthermore, even if the masterbatch can be produced, the heat resistance of the polyester resin (C) is easily reduced when the masterbatch is diluted with polyester resin (C). On the other hand, if the content of chain elongating agent (B) in the masterbatch exceeds 30% by mass, the proportion of amorphous PET (A) in the masterbatch decreases, thus mechanical properties such as impact resistance are easily reduced, and the transparency of the resin composition obtained by diluting the masterbatch with polyester resin (C) is easily reduced. Moreover, if the content of chain elongating agent (B) in the masterbatch increases, it is difficult to uniformly mix amorphous PET (A) and chain elongating agent (B) when the masterbatch is melt-blended to produce the masterbatch. Specifically, the chain elongating agent (B) will seep out in liquid form from the surface of the mixture during the manufacturing process of the masterbatch, which is difficult to solidify and therefore difficult to make into masterbatch.

[0042] [Condition (2)] When the masterbatch is diluted with polyester resin, as mentioned above, condition (2) is also necessary in order to obtain the target resin composition. That is, if the intrinsic viscosity of the resin composition sample obtained by melt-blending crystalline PET with an intrinsic viscosity IVa of 0.9 dL / g or more and 1.0 dL / g or less after melt-blending alone with the masterbatch in a ratio of 0.4% by mass of chain elongating agent (B) is set as IVb (dL / g), then 0 < IVb - IVa < 0.29. The crystalline PET in this condition (2) can be used as polyester resin (C) and is used as the raw material for the resin composition sample to which the intrinsic viscosity IVb is to be determined. The above-mentioned resin composition sample is obtained by melt-blending the masterbatch and crystalline PET, so the intrinsic viscosity IVa of crystalline PET is also the intrinsic viscosity IVa measured for the resin obtained by melt-blending crystalline PET alone. Intrinsic viscosity is the volume of a polymer per unit mass in a solution (unit: dL / g), which depends on the molecular weight of the polymer and can be used as a reference for molecular weight.

[0043] According to the above condition (2), the intrinsic viscosity IVb of the above resin composition sample is greater than the intrinsic viscosity IVa of the resin obtained by melt-blending the above crystalline PET alone (IVb>IVa). Assuming IVb=IVa, then IVb-IVa=0, which means that the same intrinsic viscosity is shown regardless of whether masterbatch is added to the above crystalline PET. Therefore, in this case, even if masterbatch is added to the polyester resin (C), no improvement in formability can be expected. Also, assuming IVb<IVa, then IVb-IVa<0, which means that even if masterbatch is added to the above crystalline PET, the intrinsic viscosity will still decrease. Therefore, in this case, compared to the effect of adding masterbatch to the polyester resin (C), the influence caused by hydrolysis during processing becomes greater, resulting in a decrease in formability. Furthermore, if IVb-IVa is 0.29 dL / g or more, the formability is easily reduced, and it is easy to cause turbidity or increase the yellowness, making it easy to become a resin composition with poor transparency.

[0044] As described above, the difference between IVb and IVa (IVb-IVa) is greater than 0 dL / g and less than 0.29 dL / g. Regarding the value of IVb-IVa, if it is near the lower limit (a value greater than or equal to 0), the larger the value, the easier it is to improve the formability. On the other hand, if it is near the upper limit (a value less than or equal to 0.29), the smaller the value, the easier it is to improve the transparency and the easier it is to reduce the yellowness. The difference between IVb and IVa (IVb-IVa) is preferably greater than or equal to 0.05 dL / g and less than or equal to 0.25 dL / g (0.05 ≤ IVb-IVa ≤ 0.25). By having the IVb-IVa value within the above-mentioned preferred range, it is easy to obtain a resin composition with better processability and formability, better transparency, and lower yellowness.

[0045] In addition, in order to select crystalline PET with an intrinsic viscosity IVa of 0.9 dL / g or more and 1.0 dL / g or less after the above-mentioned individual melt-blending, it is preferable to select crystalline PET with an intrinsic viscosity of 1.1 dL / g or more and 1.3 dL / g or less before individual melt-blending.

[0046] In this invention, the intrinsic viscosity (IV) is determined according to the method specified in JIS K7367-5, using a mixed solvent in which phenol and 1,1,2,2-tetrachloroethane (tetrachloroethane) are mixed in a mass ratio of 1:1, and the measuring instrument is an Oswald viscosity tube, using the value (dL / g) measured at 25°C.

[0047] [Condition (3)] When the masterbatch is diluted with polyester resin, in order to obtain the target resin composition, as mentioned above, condition (3) also becomes necessary. That is, the masterbatch must be mixed with polyester resin (C) under the condition that the content of chain elongating agent (B) in the resin composition containing the masterbatch and polyester resin (C) is 0.01% by mass or more and 1.0% by mass or less.

[0048] From the viewpoint that the formability of the resin composition is easily improved, the content of chain elongating agent (B) in the resin composition of condition (3) is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more. On the other hand, from the viewpoint that the transparency of the resin composition is easily improved, the content of chain elongating agent (B) in the resin composition of condition (3) is preferably 0.9% by mass or less, more preferably 0.7% by mass or less, and even more preferably 0.5% by mass or less.

[0049] (Polyester Resin (C)) Polyester resin (C) is a resin used in the dilution of masterbatch, and is a resin that, by mixing with masterbatch, constitutes a resin composition together with masterbatch. Polyester resin (C) is generally a resin having constituent units derived from aromatic dicarboxylic acids and constituent units derived from pentanediols.

[0050] Examples of polyester resins (C) include: polyethylene terephthalate (PET), polyethylene terephthalate (PTT), polyethylene terephthalate (PBT), polycyclohexanedimethyl terephthalate (PCT), polyethylene terephthalate (PEN), polyethylene terephthalate (PBN), polylactic acid (PLA), polyethylene terephthalate / ethylene isophthalate resin (I-PET), and polycarbonate (PC). Furthermore, polyester resins that replace a portion of these resins, such as glycol-modified polyethylene terephthalate (PET-G), or polyester resins regenerated through chemical recycling (chemical regeneration method) or mechanical recycling (physical regeneration method), may also be used. One type of polyester resin (C) may be used alone, or two or more types may be used in combination.

[0051] As the polyester resin (C), either crystalline polyester resin or amorphous polyester resin can be used. Among these, from the viewpoint that the improved formability can be enhanced by using the above-mentioned masterbatch, crystalline polyester resin is preferred. More preferably, crystalline polyethylene terephthalate, crystalline propylene terephthalate, crystalline polybutylene terephthalate, crystalline dimethyl cyclohexane terephthalate, crystalline polylactic acid, crystalline polyethylene terephthalate / ethylene isophthalate, and crystalline polycarbonate. Therefore, the polyester resin (C) preferably contains at least one selected from the group consisting of crystalline polyethylene terephthalate, crystalline polyethylene terephthalate, crystalline polyethylene terephthalate, crystalline polybutylene terephthalate, crystalline dimethyl cyclohexane terephthalate, crystalline polylactic acid, crystalline polyethylene terephthalate / ethylene isophthalate, and crystalline polycarbonate.

[0052] Commercially available products can also be used as polyester resins (C). Examples of commercially available PET resins include: the "KURAPET" and "BIOKURAPET" series manufactured by KURARAY Corporation; the "Unitika Polyester" series manufactured by Unitika Corporation; and the "SKYPET" series manufactured by SK Chemicals. Examples of commercially available PTT resins include: the "SORONA" series manufactured by DuPont. Examples of commercially available PBT resins include: the "TORAYCON" series manufactured by Toray Industries, the "NOVADURAN" series manufactured by Mitsubishi Chemical Corporation; and the "CELANEX" series manufactured by Polyplastics. Examples of commercially available PCT resins include: the "SKYPURA" series manufactured by SK Chemicals. Examples of commercially available PEN resins include: the "TEONEX" series manufactured by Teijin Corporation. Commercially available polylactic acid (PLA) products include, for example, the "TERRAMAC" series manufactured by Unitika. Commercially available I-PET products include, for example, the "BELLPET" series manufactured by Bell Polyester Products. Commercially available PC products include, for example, the "Panlite" series manufactured by Teijin.

[0053] (Other Components) In addition to the aforementioned amorphous PET (A) and chain elongator (B), the masterbatch may also contain other components as needed. Examples of other components include: pigments, fillers, surface treatment agents, lubricants, plasticizers, crosslinking agents, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, antibacterial agents, flame retardants, and foaming agents. Other components may be used alone or in combination of two or more.

[0054] <Method for manufacturing masterbatch> The masterbatch can be manufactured by melt-blending a material containing amorphous polyethylene terephthalate (A) and chain elongating agent (B). Other components mentioned above may also be added as needed during the melt-blending process.

[0055] As a melt-mixing method for obtaining masterbatch, examples include: using a high-speed mixer such as a Henchel mixer or a drum mixer, pre-mixing materials containing amorphous PET (A) and chain elongating agent (B), and then using a mixing device for melt-mixing. Examples of mixing devices include: Bambrey mixers, rollers, plasticizers, single-spindle extruders, twin-spindle extruders, kneaders, and pressure kneaders. Alternatively, a mixing device such as an extruder can be used to melt-mix the above materials, and the mixture can be extruded into strands, and then the stranded mixture can be processed into granules or flakes. As long as melt-mixing can be performed, there are no particular limitations on the mixing device used. From the viewpoint of high mixing capacity, it is preferable to use a pressure kneader, a Bambrey mixer, or a twin-spindle extruder. Furthermore, from the viewpoint that it is easy to use masterbatch when obtaining resin composition, masterbatch is preferably processed as described above and is in granular or flake form.

[0056] The temperature during melt mixing to obtain the masterbatch is simply the temperature at which the thermoplastic resin containing amorphous PET (A) melts; preferably, it is above 200°C and below 260°C, and more preferably, it is above 220°C and below 240°C. Melt mixing to obtain the masterbatch can be performed in one stage or in two stages. In a two-stage melt mixing, for example, a portion of the amorphous PET (A) and chain elongating agent (B) are melt-mixed, and the extruded mixture is then processed into granular or sheet form. Next, the remaining amorphous PET (A) and chain elongating agent (B), as well as other required components, can be added to the granular or sheet-like mixture, and then melt-mixed again.

[0057] As detailed above, the masterbatch of this embodiment contains amorphous PET (A) and a specific chain elongator (B), and satisfies all of the aforementioned conditions (1) to (3). Therefore, when the masterbatch is diluted with polyester resin (C), a resin composition with good processability and formability, good transparency, and low yellowness can be obtained. Accordingly, the effect of the masterbatch is achieved by mixing (melt mixing) the masterbatch with polyester resin (C), which is a diluent resin. If amorphous PET (A), chain elongator (B), and polyester resin (C) are melt-mixed without the preparation of the masterbatch, the chain elongator (B) will react locally, resulting in gelation of the mixture, which easily becomes an uneven resin composition.

[0058] <Resin Composition> The resin composition of one embodiment of the present invention contains the aforementioned masterbatch and the aforementioned polyester resin (C). The total content of the masterbatch and polyester resin (C) in the resin composition, based on the total mass of the resin composition, is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. There is no particular upper limit to the total content of the masterbatch and polyester resin (C) in the resin composition; for example, based on the total mass of the resin composition, it can also be 100% by mass. Therefore, the total content of the masterbatch and polyester resin (C) in the resin composition, based on the total mass of the resin composition, can also be set to 99% by mass or more and 100% by mass or less.

[0059] The polyester resin (C) is as described in the description of the masterbatch. From the viewpoint of improving the effect of the masterbatch, the polyester resin (C) preferably contains the following polyester resin. That is, the polyester resin (C) preferably contains at least one selected from the group consisting of crystalline polyethylene terephthalate, crystalline polyethylene terephthalate, crystalline polyethylene terephthalate, crystalline polybutylene terephthalate, crystalline polycyclohexanedimethyl terephthalate, crystalline polylactic acid, crystalline polyethylene terephthalate / ethylene isophthalate, and crystalline polycarbonate. Furthermore, the polyester resin (C) preferably contains recycled polyethylene terephthalate. Furthermore, the polyester resin (C) preferably contains polyethylene terephthalate with an intrinsic viscosity of 0.4 dL / g or more and 1.3 dL / g or less after being melt-mixed alone.

[0060] The mixing ratio of masterbatch to polyester resin (C) is preferably such that, relative to the total mass of masterbatch and polyester resin (C), the content of masterbatch is 0.1% by mass or more and 30% by mass or less. With the masterbatch content being 0.1% by mass or more, the formability of the resin composition is easily improved. On the other hand, with the masterbatch content being 30% by mass or less, the content of amorphous PET (A) in the resin composition can be suppressed, thereby easily maintaining mechanical properties such as impact resistance. Furthermore, by suppressing the content of chain elongating agent (B) in the resin composition, the aforementioned crosslinking points are made to an appropriate amount, thus easily obtaining a resin composition with suppressed turbidity and good transparency. From these viewpoints, the content of masterbatch relative to the total mass of masterbatch and polyester resin (C) is more preferably 0.2% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less.

[0061] Since the resin composition contains a masterbatch that satisfies the aforementioned condition (3), the content of the chain elongating agent (B) in the resin composition is 0.01% by mass or more and 1.0% by mass or less, based on the total mass of the resin composition. In other words, the material containing the masterbatch and the polyester resin (C) is mixed (melt-mixed) such that the content of the chain elongating agent (B) in the resin composition is 0.01% by mass or more and 1.0% by mass or less.

[0062] From the viewpoint of improving the formability of the resin composition, the content of the chain elongating agent (B) in the resin composition is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more. On the other hand, from the viewpoint of improving the transparency of the resin composition, the content of the chain elongating agent (B) in the resin composition is preferably 0.9% by mass or less, more preferably 0.7% by mass or less, and even more preferably 0.5% by mass or less.

[0063] The intrinsic viscosity of the resin composition is preferably 0.4 dL / g or more and 1.2 dL / g or less. Resin compositions within this intrinsic viscosity range can be used for various applications, and the appropriate application can be chosen based on the intrinsic viscosity value. As an example, when the intrinsic viscosity of the resin composition is 0.7 dL / g or more and 1.2 dL / g or less, the resin composition is preferably for use in bottles or sheets. Furthermore, when the intrinsic viscosity of the resin composition is 0.4 dL / g or more but less than 0.7 dL / g, the resin composition is preferably for use in films or fibers. Furthermore, when the intrinsic viscosity of the resin composition is 0.5 dL / g or more and 0.8 dL / g or less, the resin composition is preferably for injection molding. Examples of injection molding applications include eyeglass frames, cosmetic bottle caps, and washing machine parts. By using the aforementioned masterbatch, a resin composition can be obtained in which the intrinsic viscosity of polyester resin (C), which is particularly prone to decrease due to recycling, is close to the same level as the intrinsic viscosity before recycling, thereby enabling horizontal recycling.

[0064] (Other Components) In addition to the masterbatch and polyester resin (C) described above, the resin composition may also contain other components as needed. Other components that may also be contained in the masterbatch can be listed as such. The other components contained in the resin composition may be contained in the masterbatch or may be contained separately from the masterbatch by mixing with the masterbatch and polyester resin (C).

[0065] <Method for manufacturing resin composition> The resin composition can be manufactured by melt-blending a material containing a masterbatch and a polyester resin (C). During the melt-blending, other components mentioned above may also be added as needed.

[0066] As a melt-mixing method for obtaining the resin composition, examples include: using a high-speed mixer such as a Henchel mixer or a drum mixer, pre-mixing the material containing the masterbatch and polyester resin (C), and then performing melt-mixing using a mixing device. Examples of mixing devices include: a Bamboo mixer, a roller, a plasticizer, a single-spindle extruder, a twin-spindle extruder, a kneader, and a pressure kneader. Alternatively, a mixing device such as an extruder can be used to perform melt-mixing of the above materials, and after extruding the mixture into strands, the stranded mixture can be processed into granules or flakes. As long as melt mixing can be performed, there are no particular limitations on the mixing device used, but from the viewpoint of high mixing capacity, a pressure kneader, a Bamboo mixer, or a twin-spindle extruder is preferred. Furthermore, when obtaining a resin molded article from a resin composition, in order to facilitate molding of the resin composition in a molding machine, the resin composition is preferably processed as described above and is in the form of granules or flakes.

[0067] The temperature during melt mixing to obtain the resin composition is simply the temperature at which the polyester resin (C) melts, preferably 240°C or higher and 300°C or lower, more preferably 260°C or higher and 280°C or lower. Melt mixing to obtain the resin composition can be performed in one stage or in two stages. In a two-stage melt mixing, for example, a portion of the masterbatch and polyester resin (C) are melt-mixed, and the extruded mixture is then processed into granular or sheet form. Next, the remaining masterbatch and polyester resin (C), along with other required components, are added to the granular or sheet-like mixture, and melt mixing is performed again.

[0068] The resin composition of this embodiment described above, containing the aforementioned masterbatch, exhibits good processability and moldability, and possesses characteristics such as good transparency and low yellowness. Therefore, as explained in the following embodiments of resin molded articles, various resin molded articles can be manufactured by selecting various appropriate molding methods. Furthermore, by using the resin composition, as described later, resin molded articles with low haze values ​​and low yellowness can be manufactured.

[0069] <Resin Molded Article> A resin molding system according to an embodiment of the present invention provides a molded article of the aforementioned resin composition. The resin molded article can be manufactured by molding the resin composition. Examples of molding methods include: extrusion molding, T-die extrusion molding, injection molding, injection blow molding, blow molding, compression molding, and melt spinning. This allows for the provision of resin molded articles with good transparency and low yellowness in the form of food containers, non-food containers, injection molded articles, sheets, films, tapes, or fibers.

[0070] Since the resin molded article is a molded article containing the aforementioned masterbatch resin composition, it can have the properties of good transparency and low yellowness. Regarding transparency, specifically, the haze value of the resin molded article as specified in JIS K7136 is preferably 0% or more and 10% or less, more preferably 7% or less, and even more preferably 5% or less. The haze value of the resin molded article can be the value measured according to the specifications in JIS K7136.

[0071] Furthermore, the yellowness (YI value) of the resin molded article, as specified in JIS K7373, is preferably less than 15, more preferably less than 10, and even more preferably less than 5. In applications with a high number of passes (the number of times the processing is performed using a kneader or extruder), yellowing is more likely to occur due to repeated heating, but as long as the yellowness (YI value) is less than 15, it is acceptable. The yellowness (YI value) of the resin molded article can be the value measured according to the specifications of JIS K7373.

[0072] In addition, as described above, one embodiment of the present invention may be configured as follows. [1] A masterbatch for polyester resin, comprising: amorphous polyethylene terephthalate (A) and a chain elongator (B) having a weight average number of epoxy functional groups of 3 or more and 65 or less and a weight average molecular weight of 2000 or more and 30000 or less, and satisfying the following conditions (1) to (3): Condition (1): The content of the chain elongator (B) in the masterbatch is 5% by mass or more and 30% by mass or less based on the total mass of the masterbatch; Condition (2): When the intrinsic viscosity of the resin composition sample obtained by melt-blending a crystalline polyethylene terephthalate with an intrinsic viscosity IVa of 0.9dL / g or more and 1.0dL / g or less after melt-blending alone with the masterbatch in a ratio of 0.4% by mass of the content of the chain elongator (B), is set as IVb (dL / g), 0 < IVb - IVa < 0.29; Condition (3): The above masterbatch is used in combination with the above polyester resin under the condition that the content of the chain elongating agent (B) in the resin composition containing the above masterbatch and the above polyester resin is 0.01% by mass or more and 1.0% by mass or less. [2] As described in [1] above, in which the above amorphous polyethylene terephthalate (A) is melted by heating from 30°C to 300°C at 10°C / min in differential scanning calorimetry and then cooled to 30°C at 10°C / min to solidify, no exothermic peak accompanied by crystallization is observed. [3] As described in [1] or [2] above, in which the epoxy equivalent of the chain elongating agent (B) is 100 g / mol or more and 1000 g / mol or less. [4] A resin composition containing the masterbatch described in any one of [1] to [3] above and polyester resin (C). [5] The resin composition described in [4] above, wherein the polyester resin (C) contains at least one selected from the group consisting of crystalline polyethylene terephthalate, crystalline polyethylene terephthalate, crystalline polyethylene terephthalate, crystalline poly(butylene terephthalate), crystalline poly(cyclohexanedimethyl terephthalate), crystalline polylactic acid, crystalline polyethylene terephthalate / ethylene isophthalate, and crystalline polycarbonate. [6] The resin composition described in [4] or [5] above, wherein the polyester resin (C) contains recycled polyethylene terephthalate. [7] The resin composition described in any one of [4] to [6] above, wherein the polyester resin (C) contains polyethylene terephthalate having an intrinsic viscosity of 0.4 dL / g or more and 1.3 dL / g or less after melt mixing alone. [8] The resin composition described in any of [4] to [7] above, wherein the inherent viscosity of the resin composition is 0.7 dL / g or more and 1.2 dL / g or less, and is intended for use in bottles or sheets.[9] The resin composition described in any one of [4] to [7] above, wherein the inherent viscosity of the resin composition is 0.4 dL / g or more and less than 0.7 dL / g, and is for use in films or fibers.

[10] The resin composition described in any one of [4] to [7] above, wherein the inherent viscosity of the resin composition is 0.5 dL / g or more and less than 0.8 dL / g, and is for use in injection molding.

[11] A resin molded article is a molded article of the resin composition described in any one of [4] to

[10] above.

[12] The resin molded article described in

[11] above, wherein the haze value specified by JIS K7136 is 0% or more and less than 10%.

[13] The resin molded article described in

[11] or

[12] above, wherein the yellowness (YI value) specified by JIS K7373 is less than 15.

[14] The resin molded article described in any of

[11] to

[13] above is a food container, a non-food container, an injection molded article, a sheet, a film, a tape, or a fiber. [Example].

[0073] Hereinafter, an embodiment of the present invention will be specifically described with reference to the embodiments, but the embodiment of the present invention is not limited to these embodiments.

[0074] <Materials Preparation> Prepare the materials shown below. The epoxy equivalent and weight-average molecular weight of the chain extender are determined according to the following method. Furthermore, using the determined epoxy equivalent and weight-average molecular weight, the weight-average epoxy functional group of the chain extender is calculated by dividing the weight-average molecular weight by the epoxy equivalent. The intrinsic viscosity of the polyester resin (C) shown below is a value determined for resin obtained by melt-blending the polyester resin alone, and the method for determining it will be described later.

[0075] (Determination of epoxy equivalent) The epoxy equivalent (g / mol) of the chain elongator was determined according to the provisions of JIS K7236.

[0076] (Determination of Weight Average Molecular Weight) The weight average molecular weight of the chain elongating agent was determined using GPC under the following apparatus and conditions: ・GPC apparatus: Trade name "HLC-8020" (manufactured by Tosoh Corporation) ・Column: Trade names "TSKgel G2000HXL", "G3000HXL", "G4000GXL" (manufactured by Tosoh Corporation) ・Soluble solvent: Tetrahydrofuran (THF) ・Flow rate: 1.0 mL / min ・Sample concentration: 2 g / L ・Injection volume: 100 μL ・Temperature: 40℃ ・Detector: Model "RI-8020" (manufactured by Tosoh Corporation) ・Standard material: TSK standard polystyrene (manufactured by Tosoh Corporation)

[0077] (Amorphous Polyethylene Terephthalate) •A-1: Trade name "EASTAR Copolyester GN071" (manufactured by EASTAR Chemical Co., Ltd., PET-G)

[0078] (Chain elongating agent) • B-1: Trade name "JONCRYL ADR4468" (manufactured by BASF, "styrene / (meth)acrylate copolymer with glycidyl groups", weight average epoxy functional groups 23.4, weight average molecular weight 7250, epoxy equivalent 310 g / mol) • B-2: Trade name "JONCRYL ADR4400" (manufactured by BASF, "styrene / (meth)acrylate copolymer with glycidyl groups", weight average epoxy functional groups 14.6, weight average molecular weight 7100, epoxy equivalent 485 g / mol) • B-3: Trade name "MODIPER" A4100 (manufactured by Nippon Oil, "Styrene / (meth)acrylate copolymer with glycidyl groups", weight average epoxy functional groups 171.4, weight average molecular weight 240,000, epoxy equivalent 1400 g / mol) • B-4: Trade name "MARPROOF G-01100" (manufactured by Nippon Oil, "Styrene / (meth)acrylate copolymer with glycidyl groups", weight average epoxy functional groups 70.5, weight average molecular weight 12,000, epoxy equivalent 170 g / mol)

[0079] (Polyester Resin (C)) ・C-1: Trade name "MA-2101M" (Manufactured by Unitika, crystalline PET, intrinsic viscosity 0.60 dL / g) ・C-2: The above-mentioned polyester resin C-1 was melt-blended using a single-screw extruder (manufactured by Nippon Placon, NS type 40mm vented extruder, L / D=30, screw diameter=40mm, three-stage screw, compression ratio 2.0) set to 60 rpm and 280°C. The extruded resin was then extruded from the nozzle in the form of rope (strands), cooled in a water bath, and then granulated using a granulator. This operation was performed 6 times (crystalline PET, intrinsic viscosity 0.47 dL / g) ・C-3: Trade name "KURAPET KS710B-8S" (Manufactured by KURARAY, crystalline PET, intrinsic viscosity 0.96 dL / g) • C-4: Trade name "SKYPURA0302" (manufactured by SK Chemicals, PCT, intrinsic viscosity 0.63 dL / g) • C-5: Trade name "Panlite L-1250Y" (manufactured by Teijin Corporation, PC, intrinsic viscosity 1.08 dL / g)

[0080] <Preparation of Masterbatch> (Example 1-1) Amorphous PET resin A-1: ​​80 parts by weight and chain elongating agent B-1: 20 parts by weight were mixed using a small high-speed mixer to obtain a mixture. Next, the mixture was melt-kneaded using a twin-screw extruder (L / D=52.5, screw diameter=30mm) set to 350 rpm and a feed tube temperature of 200~240°C, and then extruded from the nozzle in a rope (strand) shape. After cooling the extruded mixture in a water bath, it was cut into granules using a granulator to produce granular masterbatch.

[0081] (Examples 1-2~4, Comparative Examples 1-1~6) The masterbatch was prepared in the same manner as in Example 1-1 above, except that the types of materials and amounts (unit: parts by mass) shown in the upper paragraph of Table 1 (Table 1-1 and Table 1-2) were used.

[0082] (Processability of Masterbatch) The processability of the masterbatch was evaluated according to the evaluation criteria shown below. ○: Can be used to make masterbatch. ×: Cannot be used to make masterbatch. Comparative Examples 1-1 and 1-6 were gelled, while Comparative Example 1-3 was not cured, therefore neither could be used to make masterbatch.

[0083] (Determination of Intrinsic Viscosity) The intrinsic viscosity of each of the above-mentioned polyester resins (C) was determined according to the method specified in JIS K7367-5 for resins obtained by melt-blending the polyester resin alone. Specifically, the polyester resin (C) was melt-blended using a single-screw extruder (Nippon Placon, NS type 40mm vented extruder, L / D=30, screw diameter=40mm, three-stage screw, compression ratio 2.0) set to 60 rpm and 280°C. The mixture was then extruded from the nozzle in the form of ropes (strands), cooled in a water bath, and cut using a granulator to prepare granulated resin. The material obtained by performing the above operation on polyester resin C-2 6 times (6-pass material) is designated as the material. The obtained resin was dissolved in a mixed solvent of phenol and 1,1,2,2-tetrachloroethane (tetrachloroethane) at a mass ratio of 1:1, and the intrinsic viscosity of each polyester resin (C) was determined using an Oswald viscosity tube at 25°C.

[0084] Using the prepared masterbatch and polyester resin C-3, which is a crystalline PET with an intrinsic viscosity (IVa) of 0.96 dL / g, the intrinsic viscosity IVb of the "resin composition sample" in the aforementioned condition (2) was determined. Specifically, the masterbatch and polyester resin C-3 were dry-blended at a ratio of 0.4% by mass of chain elongating agent to obtain a mixture. Then, the mixture was melt-kneaded using a single-screw extruder (Nippon Placon, NS type 40mm vented extruder, L / D=30, screw diameter=40mm, three-stage screw, compression ratio 2.0) set to 60 rpm and 280°C, and then extruded from the nozzle into a rope (strand) shape. After the strand extruded mixture was cooled in a water bath, it was cut using a granulator to produce granular resin composition samples. For the obtained resin composition samples, the intrinsic viscosity IVb was determined using the same method as described above, according to the method specified in JIS K7367-5. The lower part of Table 1 shows the values ​​of IVa, IVb, and IVb-IVa.

[0085] Table 1-1: Preparation of Masterbatch Example 1-1 1-2 1-3 1-4 Abbreviation for masterbatch MB1 MB2 MB3 MB4 Amorphous PET (A-1) (parts by weight) 80 80 90 70 Crystalline PET (C-1) (parts by weight) Chain elongating agent B-1 (parts by weight) 20 10 30 Chain elongating agent B-2 (parts by weight) 20 Chain elongating agent B-3 (parts by weight) Chain elongating agent B-4 (parts by weight) The content (mass%) of chain elongating agent in the masterbatch 20 20 10 30 Processability of masterbatch ○ ○ ○ ○ IV a (dL / g) 0.96 0.96 0.96 0.96 IV b (dL / g) 1.16 1.06 1.12 1.18 IV b -IV a (dL / g) 0.20 0.10 0.16 0.22

[0086] Table 1-2: Preparation of Masterbatch Comparative example 1-1 1-2 1-3 1-4 1-5 1-6 Abbreviation for masterbatch - MB5 - MB6 MB7 - Amorphous PET (A-1) (parts by weight) 97 60 40 80 80 Crystalline PET (C-1) (parts by weight) 80 Chain elongating agent B-1 (parts by weight) 3 40 60 20 Chain elongating agent B-2 (parts by weight) Chain elongating agent B-3 (parts by weight) 20 Chain elongating agent B-4 (parts by weight) 20 The content (mass%) of chain elongating agent in the masterbatch 3 40 60 20 20 20 Processability of masterbatch × ○ × ○ ○ × IV a (dL / g) - 0.96 - 0.96 0.96 - IV b (dL / g) - 1.18 - 1.02 1.25 - IV b -IV a (dL / g) - 0.22 - 0.06 0.29 -

[0087] <Preparation of Resin Composition> (Example 2-1) 0.125 parts by weight of the masterbatch (MB1) prepared in Example 1-1 and 99.875 parts by weight of polyester resin C-1 were dry-blended to obtain a mixture. Next, the mixture was melt-kneaded using a single-screw extruder (Nippon Placon, NS type 40mm vented extruder, L / D=30, screw diameter=40mm, three-stage screw, compression ratio 2.0) set to 60 rpm and 280°C, and then extruded from the nozzle in a rope (strand) shape. After cooling the extruded mixture in a water bath, it was cut using a granulator to produce granular resin composition samples.

[0088] <Preparation of Resin Molded Body> The resin composition prepared in Example 2-1 was dried at 140°C for 4 hours, and then a 1mm thick plate was formed using an injection molding machine (NS-40 type molding machine manufactured by Nissei Resin Kogyo Co., Ltd., with a mold clamping force of 40t) under the conditions of extrusion barrel temperature of 280°C, injection pressure of 60MPa, and mold temperature of 10°C. This was used as a test piece of the resin molded body.

[0089] (Examples 2-2~12, Comparative Examples 2-1~8) Except for using the materials and amounts (unit: parts by mass) shown in the upper part of Table 2 (Tables 2-1~2-3), granular resin compositions and test pieces were prepared in the same manner as in Example 2-1. Furthermore, Comparative Examples 2-8 did not use masterbatch, but only polyester resin (C) to prepare the test pieces. Also, in Comparative Example 2-4, the viscosity during melting was too high, and the resin did not enter the mold during injection molding, thus failing to form the sample. In Comparative Examples 2-2 and 2-8, the viscosity during melting was too low, causing resin to seep out from the mold gaps, resulting in burrs.

[0090] <Measurement and Evaluation Methods> (Processability) When producing granular resin compositions using a uniaxial extruder, the processability of the resin composition is evaluated by observing the state of the extruded compound in strands, according to the evaluation criteria shown below. The evaluation results are shown in the lower part of Table 2. AA: The strand does not cut within 10 minutes and can be processed. A: The strand cuts 1-2 times within 10 minutes, but can be processed. B: The strand cuts 3-5 times within 10 minutes, but can be processed. C: The strand cuts more than 6 times within 10 minutes.

[0091] (Moldability) The moldability of the resin composition was evaluated according to the molding conditions when forming test pieces from the resin composition using an injection molding machine, based on the evaluation criteria shown below. The evaluation results are shown in the lower part of Table 2. AA: Molding is possible under the same injection pressure conditions as when molding the polyester resin (C) monomer (hereinafter referred to as "normal conditions"). A: Molding is possible when the injection pressure conditions are increased from normal conditions to 5%. B: Molding is possible when the injection pressure conditions are increased from normal conditions to more than 5% but less than 15%. C: Molding is not possible even when the injection pressure conditions are increased from normal conditions to 15%, or the viscosity at melt is low, and resin seeps out from the mold gap, resulting in burrs.

[0092] (Determination of Intrinsic Viscosity of Resin Compositions) For the granular resin compositions prepared in Examples 2-1 to 12 and Comparative Examples 2-1 to 8, the intrinsic viscosity (IV) of the resin compositions was determined by the same method as described above, according to the method specified in JIS K7367-5. The results are shown in the lower part of Table 2.

[0093] (Transparency) A haze meter (manufactured by SUGA Testing Machine Co., Ltd.) was used to measure the haze value specified in JIS K7136 for each test piece. Based on the obtained haze values, the transparency of the test pieces was evaluated according to the evaluation criteria shown below. The results are shown in the lower part of Table 2. AA: Haze value ≥ 0% and ≤ 3%. A: Haze value > 3% and ≤ 7%. B: Haze value > 7% and ≤ 10%. C: Haze value > 10%.

[0094] (Yellowness) Using a spectrophotometer (trade name "CM-3600A", manufactured by Konica Minolta), the L*, a*, and b* values ​​of the L*a*b* color system were measured for each test piece using a D65 light source and a 10-degree field of view. Then, the yellowness (YI value) was calculated according to JIS K7373, and the yellowness of the test pieces was evaluated according to the following evaluation criteria. The results are shown in the lower part of Table 2. AA: YI value less than 5. A: YI value 5 or higher but less than 10. B: YI value 10 or higher but less than 15. C: YI value 15 or higher.

[0095] Table 2-1: Manufacturing conditions and evaluation results of resin components Example 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 Material (parts by weight) MB1 0.125 0.25 0.5 1 2 MB2 2 MB3 4 MB4 1.33 MB5 MB6 MB7 C-1 99.875 99.75 99.5 99 98 98 96 98.67 C-2 C-3 C-4 C-5 The content of chain elongating agents in resin composition (quality%) 0.025 0.05 0.10 0.20 0.40 0.40 0.40 0.40 Processability AA AA AA AA AA AA AA AA Formability B A AA AA AA AA AA AA Transparency AA AA AA AA AA AA AA A Yellowness AA AA AA AA AA AA AA AA IV (dL / g) of resin composition 0.61 0.61 0.62 0.64 0.69 0.62 0.66 0.70

[0096] Table 2-2: Preparation conditions and evaluation results of resin components Example 2-9 2-10 2-11 2-12 Material (parts by weight) MB1 2 0.5 2 2 MB2 MB3 MB4 MB5 MB6 MB7 C-1 C-2 98 C-3 99.5 C-4 98 C-5 98 The content (mass %) of chain elongating agents in the resin composition 0.40 0.10 0.40 0.40 Processability AA AA AA AA Formability AA AA AA AA Transparency AA A AA A Yellowness A AA AA AA IV (dL / g) of resin composition 0.51 0.98 0.70 1.09

[0097] Table 2-3: Preparation conditions and evaluation results of resin components Comparative example 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 Material (parts by weight) MB1 7.5 10 7.5 MB2 MB3 MB4 MB5 1 MB6 2 2 MB7 0.5 C-1 99 98 92.5 90 C-2 92.5 100 C-3 98 99.5 C-4 C-5 The content of chain elongating agents in resin composition (quality%) 0.40 0.40 0.40 0.10 1.50 2.00 1.50 0.00 Processability AA AA B A B B A A Formability AA C C C A A A C Transparency C C C B C C C AA Yellowness AA C C C C C C A IV (dL / g) of resin composition 0.69 0.61 1.02 1.03 0.78 0.96 0.65 0.48

[0098] (Application Example 1: T-die Method) Using the same type and amount of masterbatch and polyester resin as in Examples 2-4, the mixture was uniformly mixed and then extruded at 280°C using a laboratory-type plastic mixer (Labo Plastomill) equipped with a T-die to produce a sheet-like evaluation sample with a thickness of approximately 0.5 mm and a width of 100 mm. The manufactured evaluation sample was then pressed to produce a sheet with a thickness of approximately 20 μm. Visual observation of the produced sheet confirmed that a sheet with good transparency and low yellowness could be obtained.

[0099] (Application Example 2: Blow Molding Method) Using the same type and amount of masterbatch and polyester resin as in Examples 2-4, after uniform mixing, a cylindrical bottle container with a capacity of 200mL and a wall thickness of 1mm was produced using a blow molding machine heated to 280°C and with a screw diameter of 40mm. Visual observation of the produced bottle container confirmed that it could obtain a bottle container with good transparency and low yellowness.

Claims

1. A masterbatch, a masterbatch for polyester resin, wherein, Contains: amorphous polyethylene terephthalate (A); and a chain elongator (B) with a weight average number of epoxy functional groups of 3 or more and 65 or less, and a weight average molecular weight of 2000 or more and 30000 or less, and satisfies the following conditions (1) to (4): Condition (1): The content of the chain elongator (B) in the masterbatch is 5% by mass or more and 30% by mass or less based on the total mass of the masterbatch; Condition (2): When the intrinsic viscosity of the resin composition sample obtained by melt-blending a crystalline polyethylene terephthalate with an intrinsic viscosity IVa of 0.9dL / g or more and 1.0dL / g or less after melt-blending alone with the masterbatch in a ratio of 0.4% by mass of the content of the chain elongator (B), is set as IVb (dL / g), 0 < IVb - IVa < 0.29; Condition (3): The masterbatch is used in combination with the polyester resin under the condition that the content of the chain elongating agent (B) in the resin composition containing the masterbatch and the polyester resin is 0.01% by mass or more and 1.0% by mass or less; Condition (4): The content of the amorphous polyethylene terephthalate (A) in the masterbatch is 70% by mass or more and 95% by mass or less based on the total mass of the masterbatch.

2. As in request item 1, the masterbatch, wherein, When the amorphous polyethylene terephthalate (A) was melted by heating from 30°C to 300°C at a rate of 10°C / min and then cooled to 30°C at a rate of 10°C / min to solidify, no exothermic peaks were observed associated with crystallization.

3. As in request item 1, the masterbatch, wherein, The epoxy equivalent of the above chain elongating agent (B) is above 100 g / mol and below 1000 g / mol.

4. A resin composition comprising any one of claims 1 to 3 masterbatch and polyester resin (C).

5. The resin composition as claimed in claim 4, wherein, The aforementioned polyester resin (C) contains at least one selected from the group consisting of crystalline polyethylene terephthalate, crystalline polyethylene terephthalate, crystalline polyethylene terephthalate, crystalline polybutylene terephthalate, crystalline dimethyl cyclohexane terephthalate, crystalline polylactic acid, crystalline polyethylene terephthalate / ethylene isophthalate, and crystalline polycarbonate.

6. The resin composition as claimed in claim 4, wherein, The above-mentioned polyester resin (C) contains recycled polyethylene terephthalate.

7. The resin composition as claimed in claim 4, wherein, The aforementioned polyester resin (C) contains polyethylene terephthalate with an intrinsic viscosity of 0.4 dL / g or more and 1.3 dL / g or less after being melt-mixed alone.

8. The resin composition as claimed in claim 4, wherein, The inherent viscosity of the above-mentioned resin composition is 0.7 dL / g or more and 1.2 dL / g or less, and it is intended for use in bottles or sheets.

9. The resin composition as claimed in claim 4, wherein, The inherent viscosity of the above-mentioned resin composition is 0.4 dL / g or more but less than 0.7 dL / g, and it is intended for use in films or fibers.

10. The resin composition as claimed in claim 4, wherein, The inherent viscosity of the above-mentioned resin composition is 0.5 dL / g or more and 0.8 dL / g or less, and it is intended for injection molding.

11. A resin molded article, which is a molded article of the resin composition of claim 4.

12. The resin molded article as claimed in claim 11, wherein, The haze value specified by JIS K7136 is above 0% and below 10%.

13. The resin molded article as claimed in claim 11, wherein, The yellowness (YI value) specified by JIS K7373 is less than 15.

14. The resin molded body as claimed in claim 11 is a food container, a non-food container, an injection molded article, a sheet, a film, a tape, or a fiber.