Masterbatch, resin composition, and resin molded article

Abstract

The present invention provides a masterbatch that, when diluted with a polyester resin, yields a resin composition with good processability and moldability, as well as good transparency and low yellowness. [Solution] A masterbatch containing amorphous PET (A) and a chain extender (B) having a weight-average epoxy functional group count of 2 to 70 and a weight-average molecular weight of 100 to 100,000. The content of the chain extender (B) in the masterbatch is 2 to 34% by mass.

Description

[Technical Field] 【0001】 The present invention relates to a masterbatch, a resin composition, and a resin molded article. [Background technology] 【0002】 Polyester resin is currently used in a variety of fields, including PET bottles, sheets, films, and fibers. For example, the use of PET bottles, mainly for beverages, has become widespread in recent years, and the volume of use has become enormous. In Japan, clear, transparent PET bottles are used to promote recycling. In recent years, there has been a growing social demand to recycle resources by reusing waste products that are produced and consumed in large quantities, rather than simply discarding them after consumption. Under these circumstances, recycling of PET bottles, in particular, is progressing. 【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 flakes, which are then used as raw materials to manufacture new PET bottles. Cascade recycling, on the other hand, is a recycling method in which recycled polyethylene terephthalate flakes are then applied to products with lower performance requirements than PET bottles, such as films and fibers. In either case, there is a limit to the number of recycling cycles, as the polyethylene terephthalate deteriorates in moldability and strength due to thermal history and other factors with each recycling cycle. 【0004】 One method proposed for obtaining improved quality products from low-molecular-weight recycled polyethylene terephthalate flakes involves blending a chain extender effective for polyester resins and then melt-kneading the mixture. For example, Patent Document 1 discloses a modifier for crystalline polyester resins containing an amorphous polyester resin and a reactive compound having two or more glycidyl groups and / or isocyanate groups per molecule and a weight-average molecular weight of 200 to 500,000. This modifier is said to enable improved moldability in melt molding using crystalline polyester resins, particularly PET flakes recycled from used polyethylene terephthalate bottles, and improved mechanical properties while maintaining transparency. 【0005】 Furthermore, Patent Document 2 discloses a masterbatch for extending the chain of a polyester resin, which contains a predetermined polyester resin (A), an epoxy group-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 reaction product of the polyester resin (A) and resin (B). According to Patent Document 2, the respective 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. As a result, it is possible to provide a method for manufacturing a polyester resin molded article that has excellent moldability and can improve the quality of the molded article by a general processing method, and a masterbatch used in the manufacturing method. [Prior art documents] [Patent Documents] 【0006】 [Patent Document 1] Japanese Patent Publication No. 2006-45477 [Patent Document 2] International Publication No. 2023 / 153522 [Overview of the project] [Problems that the invention aims to solve] 【0007】 However, in the technologies disclosed in Patent Documents 1 and 2 described above, with regard to the transparency of the molded article, it is understood that the improvement or maintenance of transparency is achieved by the types and ratios of monomer components such as the diol (glycol) component that constitutes the polyester resin used. There is a need for a technology that can obtain a resin composition with good transparency by mixing with a polyester resin to be modified or chain-extended, such as in the form of a modifier or a chain extension masterbatch. 【0008】 Therefore, the present invention aims to provide a masterbatch for polyester resin, which, when diluted with a polyester resin, can obtain a resin composition with good processability and moldability, as well as good transparency and low yellowness. 【Means for Solving the Problems】 【0009】 That is, according to the present invention, there is provided a masterbatch for polyester resin, which contains amorphous polyethylene terephthalate (A) and a chain extender (B) having a weight average epoxy functional group number of 2 or more and 70 or less and a weight average molecular weight of 100 or more and 100,000 or less, and the content of the chain extender (B) in the masterbatch satisfies 2% by mass or more and 34% by mass or less based on the total mass of the masterbatch. 【Effects of the Invention】 【0010】 According to the present invention, it is possible to provide a masterbatch for polyester resin, which, when diluted with a polyester resin, can obtain a resin composition with good processability and moldability, as well as good transparency and low yellowness. 【Modes for Carrying Out the Invention】 【0011】 Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. 【0012】 <Masterbatch> A masterbatch of one embodiment of the present invention (hereinafter sometimes simply referred to as "masterbatch") is a masterbatch for polyester resin. In this disclosure, the polyester resin to which the masterbatch is used may be 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 this disclosure, a composition obtained by mixing the masterbatch and polyester resin (C) by melt kneading or the like, and a composition compared thereto, will be referred to as "resin composition". Furthermore, in this disclosure, a molded article obtained by molding a resin composition by a method such as injection molding will be referred to as "resin molded article". 【0013】 The masterbatch contains amorphous polyethylene terephthalate (A) and a chain extender (B). The chain extender (B) has a weight-average epoxy functional group count of 2 to 70 and a weight-average molecular weight of 100 to 100,000. Furthermore, the content of the chain extender (B) in the masterbatch satisfies the requirement of being 2% to 34% by mass based on the total mass of the masterbatch. 【0014】 By using a masterbatch containing amorphous polyethylene terephthalate (A) and the above-mentioned specific chain extender (B), and satisfying all of conditions (1) to (3), it is possible to obtain the desired resin composition. That is, when the masterbatch is diluted with polyester resin (C), it is possible to obtain a resin composition that has good processability and moldability, is less prone to clouding, has good transparency, and has low yellowness. 【0015】 The following provides a detailed explanation of each component of the masterbatch. 【0016】 (Amorphous polyethylene terephthalate (A)) The masterbatch contains amorphous polyethylene terephthalate (A) (hereinafter sometimes referred to as "amorphous PET(A)"). Amorphous PET(A) is the base resin in the masterbatch. By using amorphous PET(A) as the base resin in the masterbatch, the crystallization temperature of polyester resin (C) can be lowered when the masterbatch is diluted with polyester resin (C). This contributes to providing a resin composition with good processability, moldability, and transparency. 【0017】 On the other hand, using crystalline polyethylene terephthalate (hereinafter sometimes referred to as "crystalline PET") as the base resin for the masterbatch instead of amorphous PET (A) can make masterbatch production difficult. This is because, coupled with the fact that the processing temperature of crystalline PET is higher than that of amorphous PET, the crosslinking reaction between crystalline PET and the chain extender (B) is accelerated during the masterbatch manufacturing process, which can lead to gelation. 【0018】 Polyethylene terephthalate can be synthesized by dehydration condensation of ethylene glycol and terephthalic acid, or by transesterification of ethylene glycol and dimethyl terephthalate. Amorphous PET(A) is polyethylene terephthalate (PET) that does not have a crystallization temperature, and includes so-called "A-PET" (abbreviation for amorphous polyethylene terephthalate) and "PET-G" (abbreviation for glycol-modified polyethylene terephthalate). PET-G is amorphous PET in which some of the ethylene glycol units in PET (for example, about 30-40 mol%) are replaced with cyclohexanedimethanol units. 【0019】 Among amorphous PET (A), glycol-modified polyethylene terephthalate (PET-G) is preferred. By using PET-G, the crystallization temperature of the diluent polyester resin (C) can be more easily lowered, which contributes to providing a resin composition with better processability, moldability, and transparency. 【0020】 The crystalline and amorphous nature of thermoplastic resins can be determined by differential scanning calorimetry (DSC) by observing the presence or absence of an exothermic peak associated with crystallization when the thermoplastic resin is heated from 30°C to 300°C at a rate of 10°C / min to melt, and then cooled down to 30°C at a rate of 10°C / min to solidify. Specifically, if the above exothermic peak is observed, the thermoplastic resin can be determined to be crystalline. If the above exothermic peak is not observed, the thermoplastic resin can be determined to be amorphous. Therefore, as amorphous PET(A), amorphous PET(A) can be used in which no exothermic peak associated with crystallization is observed when the thermoplastic resin is heated from 30°C to 300°C at a rate of 10°C / min to melt, and then cooled down to 30°C at a rate of 10°C / min to solidify in differential scanning calorimetry. A differential scanning calorimetry (DSC) is used to observe the exothermic peak. 【0021】 Amorphous PET(A) can also be commercially available. Examples of commercially available amorphous PET(A) include the "EASTAR" series from Eastman Chemical Corporation and the "SKYGREEN" series from SK Chemical Corporation. Amorphous PET(A) may be used alone or in combination of two or more types. 【0022】 The content of amorphous PET(A) in the masterbatch is preferably 70% to 95% by mass, more preferably 72% to 92% by mass, and even more preferably 75% to 90% by mass, based on the total mass of the masterbatch. When the content of amorphous PET(A) in the masterbatch is within the above range, a resin composition with better processability, moldability, and transparency, and lower yellowness is more easily obtained when the masterbatch is diluted with polyester resin(C). 【0023】 (Chain elongator (B)) The masterbatch contains a chain extender (B). This chain extender (B) has a weight-average epoxy functional group count of 2 to 70 and a weight-average molecular weight of 100 to 100,000. Since the weight-average epoxy functional group count of chain extender (B) is 2 to 70, it has glycidyl groups (epoxy groups). The glycidyl groups of chain extender (B) can react with at least one of the hydroxyl groups and / or carboxyl groups (hereinafter sometimes referred to as "hydroxyl groups and / or carboxyl groups") of the polyester resin (C). Therefore, when the masterbatch is diluted with the polyester resin (C), the chain extender (B) reacts with the polyester resin (C) to extend the chains of the polyester resin (C) and increase its molecular weight, thereby suppressing yellowing and clouding while suppressing deformation during molding. 【0024】 The weight-average number of epoxy functional groups and the weight-average molecular weight of the chain extender (B) must both be within the specified ranges described above. Preferably, the weight-average number of epoxy functional groups of the chain extender (B) is 2 or more and 70 or less, and the weight-average molecular weight of the chain extender (B) is 4000 or more and 20000 or less, and more preferably 7000 or more and 12000 or less. 【0025】 If the weight-average epoxy functional group count of the chain extender (B) is 2 or more and 70 or less, or greater than 70, and the weight-average molecular weight is less than 100, excessive crosslinking reactions are likely to occur between the chain extender (B) and the polyester resin (C) in the masterbatch. As a result, the resin composition obtained by diluting with the polyester resin (C) tends to whiten and have poor transparency. Furthermore, the viscosity may increase during melt-kneading of the masterbatch and the polyester resin (C), resulting in insufficient dispersion of the chain extender (B) in the polyester resin (C). On the other hand, if the weight-average epoxy functional group count of the chain extender (B) is 2 or more and 70 or less, or less than 2, and the weight-average molecular weight is greater than 100,000, the above crosslinking reaction is less likely to occur sufficiently, and the resulting resin composition may have poor moldability. Also, if the weight-average epoxy functional group count of the chain extender (B) is less than 2, and the weight-average molecular weight is less than 100, the above crosslinking reaction will be insufficient, and the resulting resin composition may have poor processability and moldability. On the other hand, if the weight-average epoxy functional group count of the chain extender (B) exceeds 70 and the weight-average molecular weight exceeds 100,000, the above crosslinking reaction is more likely to occur in excess, resulting in a resin composition that is prone to whitening and poor transparency when diluted with polyester resin (C). 【0026】 In this disclosure, the weight-average molecular weight of the chain extender (B) refers to the polystyrene-converted value measured by gel permeation chromatography (GPC). Specifically, the weight-average molecular weight of the chain extender (B) can be obtained by measuring it using the following apparatus and conditions. • GPC device: Product name "HLC-8020" (manufactured by Tosoh Corporation) • Columns: Product names "TSKgel G2000HXL", "G3000HXL", "G4000GXL" (manufactured by Tosoh Corporation) • Solvent: Tetrahydrofuran (THF) ·Flow rate: 1.0mL / min • Sample concentration: 2g / L ·Injection volume: 100μL ·Temperature: 40℃ • Detector: Model number "RI-8020" (manufactured by Tosoh Corporation) • Standard material: TSK standard polystyrene (manufactured by Tosoh Corporation) 【0027】 As described above, the chain extender (B) has glycidyl groups (epoxy groups), which are functional groups that can react with the hydroxyl groups and / or carboxyl groups of the polyester resin (C). The average number of glycidyl groups (epoxy groups) per molecule of the chain extender (B) is expressed as the weight-average number of epoxy functional groups, which can be set appropriately according to the desired reaction strength. The weight-average number of epoxy functional groups can be determined by dividing the weight-average molecular weight of the chain extender (B) by the epoxy equivalent. For example, by determining the desired weight-average molecular weight, the ratio of polymerizable monomers having glycidyl groups (epoxy groups) to other polymerizable monomers can be adjusted and polymerized. This makes it possible to produce a chain extender (B) having the desired average number of glycidyl groups (epoxy groups) per molecule. 【0028】 As an example, we will explain the case of producing a chain extender (B) using glycidyl methacrylate as a polymerizable monomer having glycidyl groups and styrene as another polymerizable monomer. Specifically, when producing a chain extender (B) with a weight-average molecular weight of 5000 and an average of 4 glycidyl groups (epoxy groups) per molecule using styrene and glycidyl methacrylate, the process is as follows: By charging styrene (molecular weight 104.15) and glycidyl methacrylate (molecular weight 142.15) in a mass ratio of styrene:glycidyl methacrylate = 10.6:1, a styrene / glycidyl methacrylate copolymer can be obtained as the desired chain extender (B). 【0029】 The weight-average number of epoxy functional groups in the chain extender (B) is 2 to 70, preferably 4 to 50. Due to the effect of the chain extender (B), when the masterbatch and polyester resin (C) are melt-kneaded, the chain extender (B) reacts with the hydroxyl groups and / or carboxyl groups of the polyester resin (C), and a portion of it is crosslinked. As a result, the strength during melt-kneading is improved, and it becomes easier to obtain a resin composition with good moldability. 【0030】 If the weight-average molecular weight of the chain extender (B) is between 100 and 100,000 or greater than 100,000, and the weight-average number of epoxy functional groups is less than 2, the number of crosslinking points between the chain extender (B) and the polyester resin (C) in the masterbatch will be small. As a result, the strength improvement during melt mixing of the masterbatch and the polyester resin (C) may be insufficient, and the moldability of the resulting resin composition may be reduced. On the other hand, if the weight-average molecular weight of the chain extender (B) is between 100 and 100,000 or less than 100, and the weight-average number of epoxy functional groups is greater than 70, there will be too many crosslinking points, and the reaction between the chain extender (B) and the polyester resin (C) will proceed too much. As a result, the resulting resin composition may whiten and have poor transparency, and the reaction with the polyester resin (C) may occur too much, resulting in a resin composition with poor moldability. Furthermore, if the weight-average molecular weight of the chain extender (B) is less than 100 and the weight-average number of epoxy functional groups is less than 2, the above crosslinking reaction will be insufficient, and the resulting resin composition may have poor processability and moldability. On the other hand, if the weight-average molecular weight of the chain extender (B) is greater than 100,000 and the weight-average number of epoxy functional groups is greater than 70, the above crosslinking reaction is more likely to occur in excess, so the resin composition obtained by diluting with polyester resin (C) tends to whiten and have poor transparency. 【0031】 The epoxy equivalent of the chain extender (B) is preferably 100 g / mol or more and 1000 g / mol or less, more preferably 150 g / mol or more and 800 g / mol or less, and even more preferably 200 g / mol or more and 600 g / mol or less. When the epoxy equivalent of the chain extender (B) is 100 g / mol or more, the number of crosslinking points increases appropriately, which tends to improve the strength during melt mixing of the masterbatch and the polyester resin (C), and the resulting resin composition tends to have good moldability. On the other hand, when the epoxy equivalent of the chain extender (B) is 1000 g / mol or less, the number of crosslinking points is kept to an appropriate level, and the resulting resin composition tends to have good transparency. In this disclosure, the epoxy equivalent of the chain extender (B) can be a value measured in accordance with the provisions of JIS K7236. 【0032】 The chain extender (B) may have glycidyl groups (epoxy groups) in the main chain, side chains, or terminals of the molecular chain, or in multiple of these locations. The type of chain extender (B) is not particularly limited, as long as both the weight-average number of epoxy functional groups and the weight-average molecular weight are within the specific ranges described above. As mentioned above, suitable chain extenders (B) include copolymers of polymerizable monomers having glycidyl groups (epoxy groups) and monomer mixtures containing other polymerizable monomers. The copolymer may be a random copolymer, a block copolymer, a graft copolymer, or an alternating copolymer. 【0033】 Preferred examples of polymerizable monomers having a glycidyl group include (meth)acrylate monomers having a glycidyl group (hereinafter sometimes referred to as "glycidyl (meth)acrylate monomers"). Examples of glycidyl (meth)acrylate monomers include glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, and allyl glycidyl ether. One or more of these can be used. Among these, glycidyl acrylate and glycidyl methacrylate are preferred. In this disclosure, the term "(meth)acrylate" means that both "acrylate" and "methacrylate" are included. 【0034】 Other suitable examples of 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 styrene monomers can be used. Examples of (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and ethylhexyl (meth)acrylate. One or more (meth)acrylate monomers can be used. Examples of olefin monomers include ethylene, propylene, butadiene, and isoprene. One or more olefin monomers can be used. 【0035】 Preferred types of chain extender (B) include copolymers of styrene monomers and glycidyl (meth)acrylate monomers (styrene / glycidyl (meth)acrylate copolymer), copolymers of styrene monomers, (meth)acrylate monomers and glycidyl (meth)acrylate monomers (styrene / (meth)acrylate / glycidyl (meth)acrylate copolymer), and copolymers of styrene monomers, olefin monomers and glycidyl (meth)acrylate monomers (styrene / olefin / glycidyl (meth)acrylate copolymer). 【0036】 Commercially available chain extenders (B) can also be used. Examples of commercially available chain extenders (B) include the "Joncryl" ADR series from BASF, the "Alphon" series from Toagosei Co., Ltd., the "Marproof" series from NOF Corporation, the "Bondfast" series from Sumitomo Chemical Co., Ltd., and the "Rotada" series from SK Chemical Co., Ltd. Chain extenders (B) may be used individually or in combination of two or more types. 【0037】 The content of the chain extender (B) in the masterbatch is preferably 2% by mass or more and 34% by mass or less based on the total mass of the masterbatch. Preferably, the content of the chain extender (B) in the masterbatch is 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, based on the total mass of the masterbatch. When the content of the chain extender (B) in the masterbatch is within the above range, a resin composition with better processability, moldability, and transparency is more likely to be obtained when the masterbatch is diluted with polyester resin (C). 【0038】 If the content of chain extender (B) in the masterbatch is less than 2% by mass, the masterbatch is prone to gelation when amorphous PET (A) and chain extender (B) are melt-kneaded together to produce the masterbatch, making masterbatch production difficult. Furthermore, even if the masterbatch can be produced, when it is diluted with polyester resin (C), the heat resistance of the polyester resin (C) tends to decrease. On the other hand, if the content of chain extender (B) in the masterbatch exceeds 34% by mass, the proportion of amorphous PET (A) in the masterbatch decreases, which tends to reduce mechanical properties such as impact resistance, and the transparency of the resin composition obtained by diluting the masterbatch with polyester resin (C) tends to decrease. In addition, if the content of chain extender (B) in the masterbatch is high, it becomes difficult to uniformly mix amorphous PET (A) and chain extender (B) when melt-kneading them together to produce the masterbatch. Specifically, the chain extender (B) tends to come out in liquid form on the surface of the mixture during the masterbatch manufacturing process, making it difficult for the mixture to solidify and thus making it difficult to produce the masterbatch. 【0039】 [Condition (1)] When diluting the masterbatch with polyester resin, it is preferable to satisfy condition (1) in order to obtain the desired resin composition. That is, the intrinsic viscosity IV after melt-kneading alone. aCrystalline PET with an intrinsic viscosity of 0.9 dL / g or more and 1.0 dL / g or less and a masterbatch are melt-kneaded at a ratio such that the content of the chain extender (B) is 0.4% by mass, and the intrinsic viscosity of the resin composition sample obtained is IV b (dL / g). When 0 < IV b - IV a < 0.29. The crystalline PET under this condition (1) can be used as the polyester resin (C) and is used as the raw material of the resin composition sample for measuring the intrinsic viscosity IV b . Since the above resin composition sample is obtained by melt-kneading a masterbatch and crystalline PET, for the intrinsic viscosity IV a of crystalline PET, the intrinsic viscosity IV a measured for the resin obtained by melt-kneading crystalline PET alone is adopted. The intrinsic viscosity is the volume per unit mass occupied by the polymer in solution (unit: dL / g), depends on the molecular weight of the polymer, and is used as a measure of the molecular weight. 【0040】 From the above condition (1), the intrinsic viscosity IV b of the above resin composition sample is greater than the intrinsic viscosity IV a of the resin obtained by melt-kneading the above crystalline PET alone (IV a > IV b > IV a ). If IV b = IV a , then IV b - IV a = 0, which means that the same intrinsic viscosity is shown regardless of the addition of the masterbatch to the above crystalline PET. Therefore, in this case, even if the masterbatch is added to the polyester resin (C), improvement in moldability cannot be expected. Also, if IV a < IV b < IV a , then IV b - IV a < 0, which means that the intrinsic viscosity decreases even when the masterbatch is added to the above crystalline PET. Therefore, in this case, the influence of hydrolysis during processing etc. is greater than the effect of adding the masterbatch to the polyester resin (C), and the moldability deteriorates. Furthermore, IV a b-IV a If the concentration is 0.29 dL / g or higher, moldability tends to decrease, and the resin composition is likely to become cloudy or yellowish, resulting in poor transparency. 【0041】 As mentioned above, IV b and IV a The difference (IV) b -IV a ) is greater than 0 dL / g and less than 0.29 dL / g. IV b -IV a Regarding the value, near the lower limit (values ​​above 0 but close to 0), larger values ​​tend to improve moldability. On the other hand, near the upper limit (values ​​below 0.29 but close to 0.29), smaller values ​​tend to improve transparency and decrease yellowness. IV b and IV a The difference (IV) b -IV a ) is between 0.05 dL / g and 0.25 dL / g (0.05 ≤ IV b -IV a It is preferable that the value is ≤0.25. IV b -IV a When the value is within the above preferred range, it becomes easier to obtain a resin composition with better processability and moldability, as well as better transparency and lower yellowness. 【0042】 Furthermore, the intrinsic viscosity IV after melting and kneading the above-mentioned mixture alone a To select a crystalline PET with an intrinsic viscosity of 0.9 dL / g to 1.0 dL / g, it is advisable to select a crystalline PET with an intrinsic viscosity of 1.1 dL / g to 1.3 dL / g before melting and kneading it alone. 【0043】 In this disclosure, the intrinsic viscosity (IV) is the value (dL / g) measured at 25°C using an Ostwald viscosity tube, in accordance with the method specified in JIS K7367-5, with a mixed solvent prepared by mixing phenol and 1,1,2,2-tetrachloroethane (tetrachloroethane) in a mass ratio of 1:1 as the solvent. 【0044】 [Condition (2)] When a masterbatch is diluted with a polyester resin, it is preferable to satisfy condition (2) in order to obtain the desired resin composition. That is, the masterbatch must be used after being mixed with the polyester resin (C) under the condition that the content of the chain extender (B) in the resin composition containing the masterbatch and the polyester resin (C) is 0.01% by mass or more and 1.0% by mass or less. 【0045】 From the viewpoint of improving the moldability of the resin composition, the content of the chain extender (B) in the resin composition under condition (2) 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 extender (B) in the resin composition under condition (2) 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. 【0046】 (Polyester resin (C)) Polyester resin (C) is a resin used for diluting the masterbatch, and when mixed with the masterbatch, it constitutes the resin composition together with the masterbatch. Polyester resin (C) is typically a resin having constituent units derived from aromatic dicarboxylic acids and constituent units derived from alkylenediols. 【0047】 Examples of polyester resin (C) include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polycyclohexylenedimethylene terephthalate (PCT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), polylactic acid (PLA), polyethylene terephthalate-isophthalate resin (I-PET), and polycarbonate (PC). Alternatively, polyester resins in which a portion of these resins are replaced, such as glycol-modified polyethylene terephthalate (PET-G), or polyester resins recycled by chemical recycling or mechanical recycling may be used. Polyester resin (C) may be used alone or in combination of two or more types. 【0048】 As the polyester resin (C), both crystalline polyester resin and amorphous polyester resin can be used. Among these, it is preferable to use a crystalline polyester resin because using the masterbatch described above provides a high improvement in moldability. Among these, crystalline polyethylene terephthalate, crystalline polytrimethylene terephthalate, crystalline polybutylene terephthalate, crystalline polycyclohexylenedimethylene terephthalate, crystalline polylactic acid, crystalline polyethylene terephthalate / isophthalate, and crystalline polycarbonate are more preferable. Therefore, it is more preferable that the polyester resin (C) includes at least one selected from the group consisting of crystalline polyethylene terephthalate, crystalline polytrimethylene terephthalate, crystalline polybutylene terephthalate, crystalline polycyclohexylenedimethylene terephthalate, crystalline polylactic acid, crystalline polyethylene terephthalate / isophthalate, and crystalline polycarbonate. 【0049】 Commercially available polyester resins (C) may be used. Examples of commercially available PET include the "Clapet" and "BioClapet" series from Kuraray Co., Ltd., the "Unitika Polyester" series from Unitika Corporation, and the "SKYPET" series from SK Chemical Co., Ltd. Examples of commercially available PTT include the "Sorona" series from DuPont. Examples of commercially available PBT include the "Torecon" series from Toray Industries, Inc., the "Novaduran" series from Mitsubishi Chemical Corporation, and the "Duranex" series from Polyplastics Corporation. Examples of commercially available PCT include the "SKYPURA" series from SK Chemical Co., Ltd. Examples of commercially available PEN include the "Teonex" series from Teijin Corporation. Examples of commercially available polylactic acid include the "Terramac" series from Unitika Corporation. Examples of commercially available I-PET products include the "Bellpet" series manufactured by Bell Polyester Products Co., Ltd. Examples of commercially available PC products include the "Panlight" series manufactured by Teijin Corporation. 【0050】 (Other ingredients) The masterbatch may contain other components as needed, in addition to the amorphous PET (A) and chain extender (B) described above. Examples of other components include pigments, fillers, surface treatment agents, lubricants, plasticizers, crosslinking agents, UV absorbers, light stabilizers, antioxidants, antistatic agents, antibacterial agents, flame retardants, and foaming agents. One of these other components may be used alone, or two or more may be used in combination. 【0051】 <How to manufacture a masterbatch> A masterbatch can be produced by melt-kneading materials containing amorphous polyethylene terephthalate (A) and a chain extender (B). During this melt-kneading process, other components as described above may be added as needed. 【0052】 One method for melt-kneading to obtain a masterbatch is to pre-mix materials containing amorphous PET (A) and chain extender (B) using a high-speed mixer such as a Henschel mixer or a mixer such as a tumbler, and then melt-knead them using a kneading device. Examples of kneading devices include Banbury mixers, rolls, plastographs, single-screw extruders, twin-screw extruders, kneaders, and pressure kneaders. The materials may be melt-kneaded using a kneading device such as an extruder, and the kneaded material may be extruded into strands, and then processed into pellets or flakes. The kneading device used is not particularly limited as long as it can melt-knead, but pressure kneaders, Banbury mixers, or twin-screw extruders are preferred due to their high kneading capacity. Furthermore, from the viewpoint of ease of use when obtaining a resin composition, it is preferable that the masterbatch is processed as described above and is in the form of pellets or flakes. 【0053】 The temperature during melt-mixing to obtain the masterbatch should be any temperature at which the thermoplastic resin containing amorphous PET(A) melts, preferably between 200°C and 260°C, and more preferably between 220°C and 240°C. The melt-mixing to obtain the masterbatch may be carried out in one stage or in two stages. In the two-stage melt-mixing, for example, some of the amorphous PET(A) and chain extender (B) are melt-mixed, and the extruded mixture is processed into a pellet or flake form. Then, the remaining amorphous PET(A) and chain extender (B), as well as other components as needed, are added to the pellet or flake mixture, and the mixture is melt-mixed again. 【0054】 As detailed above, the masterbatch of this embodiment contains amorphous PET (A) and a specific chain extender (B). Therefore, when this masterbatch is diluted with polyester resin (C), it is possible to obtain a resin composition that has good processability and moldability, is less prone to clouding, has good transparency, and low yellowness. Thus, the effect of the masterbatch is realized by mixing (melt kneading) the polyester resin (C), which is the diluent, with the masterbatch. If amorphous PET (A), chain extender (B), and polyester resin (C) are melt-kneaded without preparing a masterbatch, the chain extender (B) will react locally, resulting in gelation of the mixture and a non-uniform resin composition. 【0055】 <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 is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the total mass of the resin composition. The upper limit of the total content of the masterbatch and polyester resin (C) in the resin composition is not particularly limited, and for example, it may be 100% by mass based on the total mass of the resin composition. Therefore, the total content of the masterbatch and polyester resin (C) in the resin composition may be 99% by mass or more and 100% by mass or less, based on the total mass of the resin composition. 【0056】 The polyester resin (C) is as described in the description of the masterbatch. From the viewpoint of enhancing the effect of the masterbatch, it is preferable that the polyester resin (C) contains the following polyester resins. Specifically, it is preferable that the polyester resin (C) contains at least one selected from the group consisting of crystalline polyethylene terephthalate, crystalline polytrimethylene terephthalate, crystalline polybutylene terephthalate, crystalline polycyclohexylene dimethylene terephthalate, crystalline polylactic acid, crystalline polyethylene terephthalate isophthalate, and crystalline polycarbonate. It is also preferable that the polyester resin (C) contains recycled polyethylene terephthalate. Furthermore, it is preferable that 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 as measured after melt-kneading alone. 【0057】 The mixing ratio of the masterbatch and polyester resin (C) is preferably such that the masterbatch content is 0.1% by mass or more and 30% by mass or less relative to the total mass of the masterbatch and polyester resin (C). A masterbatch content of 0.1% by mass or more tends to result in good moldability of the resin composition. On the other hand, a masterbatch content of 30% by mass or less suppresses the content of amorphous PET (A) in the resin composition, making it easier to maintain mechanical properties such as impact resistance. Furthermore, suppressing the content of chain extenders (B) in the resin composition results in an appropriate number of crosslinking points, thus suppressing clouding and making it easier to obtain a resin composition with good transparency. From these viewpoints, the masterbatch content relative to the total mass of the masterbatch and polyester resin (C) is more preferably 0.2% by mass or more and 10% by mass or less, and even more preferably 0.5% by mass or more and 5% by mass or less. 【0058】 Since the resin composition contains a masterbatch that satisfies the above-mentioned condition (3), the content of the chain extender (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 masterbatch and the material containing the polyester resin (C) are mixed (melt-kneaded) so that the content of the chain extender (B) in the resin composition is 0.01% by mass or more and 1.0% by mass or less. 【0059】 From the viewpoint of improving the moldability of the resin composition, the content of the chain extender (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 extender (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. 【0060】 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 range of intrinsic viscosity can be applied to a variety of uses, and are used for the most appropriate application depending on the value of the intrinsic viscosity. In one embodiment, if 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 bottles or sheets. If the intrinsic viscosity of the resin composition is 0.4 dL / g or more and less than 0.7 dL / g, the resin composition is preferably for films or fibers. Furthermore, if 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 applications for injection molding include eyeglass frames, cosmetic caps, and washing machine parts. By using the aforementioned masterbatch, it is possible to obtain a resin composition in which the intrinsic viscosity of polyester resin (C), which is particularly prone to decrease through recycling, is brought close to the same level as before recycling, thereby enabling horizontal recycling. 【0061】 (Other ingredients) The resin composition may contain other components as needed, in addition to the masterbatch and polyester resin (C) described above. Other components may include those that are also included in the masterbatch. These other components may be included in the resin composition either in the masterbatch or separately, mixed together with the masterbatch and polyester resin (C). 【0062】 <Method for producing resin compositions> The resin composition can be produced by melt-kneading a masterbatch and a material containing polyester resin (C). During this melt-kneading process, other components as described above may be added as needed. 【0063】 One method for melt-kneading a resin composition is to pre-mix the masterbatch and the polyester resin (C) using a high-speed mixer such as a Henschel mixer or a mixer such as a tumbler, and then melt-knead the mixture using a kneading device. Examples of kneading devices include Banbury mixers, rolls, plastographs, single-screw extruders, twin-screw extruders, kneaders, and pressure kneaders. The materials may be melt-kneaded using a kneading device such as an extruder, and the kneaded material may be extruded into strands, which may then be processed into pellets or flakes. The kneading device used is not particularly limited as long as it can melt-knead, but pressure kneaders, Banbury mixers, or twin-screw extruders are preferred due to their high kneading capacity. Furthermore, when obtaining a resin molded article from the resin composition, it is preferable that the resin composition is processed as described above to be in pellet or flake form so that it is easy to mold in a molding machine. 【0064】 The temperature during melt-kneading to obtain the resin composition should be any temperature at which the polyester resin (C) melts, preferably 240°C to 300°C, and more preferably 260°C to 280°C. The melt-kneading to obtain the resin composition may be carried out in one stage or in two stages. In the two-stage melt-kneading, for example, a portion of the masterbatch and polyester resin (C) is melt-kneaded, and the extruded mixture is processed into a pellet or flake form. Then, the remaining masterbatch and polyester resin (C), as well as other components as needed, are added to the pellet or flake mixture, and the mixture is melt-kneaded again. 【0065】 As described in detail above, the resin composition of this embodiment contains the aforementioned masterbatch, and therefore has good processability and moldability, as well as properties such as good transparency and low yellowness. Therefore, as will be explained in the embodiments of the resin molded articles described later, various types of resin molded articles can be manufactured by selecting various appropriate molding methods. Furthermore, by using this resin composition, resin molded articles with low haze values ​​and low yellowness can be manufactured, as will be described later. 【0066】 <Resin molded product> A resin molded article of one embodiment of the present invention is 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 makes it possible to provide a resin molded article with good transparency and low yellowness for use as a food container, non-food container, film, tape, sheet, or fiber. It is particularly useful for dry film resist supports, insert molding, and release films. 【0067】 Since the resin molded article is a molded article of a resin composition containing the aforementioned masterbatch, it is possible to have good transparency and low yellowness. Specifically regarding transparency, the resin molded article preferably has a haze value of 0% or more and 10% or less as defined in JIS K7136, more preferably 7% or less, and even more preferably 5% or less. The haze value of the resin molded article can be a value measured in accordance with the provisions of JIS K7136. 【0068】 Furthermore, the resin molded article preferably has a yellowness (YI value) of less than 15, more preferably less than 10, and even more preferably less than 5, as defined in JIS K7373. In applications with a high number of passes (number of times processed in a kneader or extruder), repeated heat is applied, which tends to accelerate yellowing, but a yellowness (YI value) of less than 15 is sufficient. The yellowness (YI value) of the resin molded article can be a value measured in accordance with the provisions of JIS K7373. 【0069】 As mentioned above, one embodiment of the present invention can have the following configuration. [1] A masterbatch for polyester resin, Amorphous polyethylene terephthalate (A) and, A chain extension agent (B) having a weight-average epoxy functional group count of 2 or more and 70 or less, and a weight-average molecular weight of 100 or more and 100,000 or less, is contained, A masterbatch in which the content of the chain extender (B) in the masterbatch is 2% by mass or more and 34% by mass or less, based on the total mass of the masterbatch. [2] The masterbatch described in [1] above that satisfies the following conditions (1) to (2). Condition (1): Intrinsic viscosity IV after melting and kneading alone a The intrinsic viscosity of the resin composition sample obtained by melt-kneading crystalline polyethylene terephthalate having a concentration of 0.9 dL / g or more and 1.0 dL / g or less with the masterbatch in a proportion such that the chain extender (B) content is 0.4% by mass is IV b When set to (dL / g), 0 <IV b-IV a <0.29. Condition (2): The masterbatch is used by mixing it with the polyester resin under the condition that the content of the chain extender (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. [3] The masterbatch according to [1] or [2] above, wherein the amorphous polyethylene terephthalate (A) does not exhibit an exothermic peak associated with crystallization when it is melted by raising the temperature from 30°C to 300°C at 10°C / min and then solidified by lowering the temperature to 30°C at 10°C / min in differential scanning calorimetry. [4] A masterbatch according to any of [1] to [3] above, wherein the epoxy equivalent of the chain extender (B) is 100 g / mol or more and 1000 g / mol or less. [5] A resin composition comprising a masterbatch according to any of [1] to [4] above and a polyester resin (C). [6] The resin composition according to [5] above, wherein the polyester resin (C) comprises at least one selected from the group consisting of crystalline polyethylene terephthalate, crystalline polybutylene terephthalate, crystalline polycyclohexylene dimethylene terephthalate, crystalline polylactic acid, crystalline polyethylene terephthalate isophthalate, and crystalline polycarbonate. [7] The resin composition according to [5] or [6] above, wherein the polyester resin (C) comprises recycled polyethylene terephthalate. [8] The resin composition according to any one of [5] to [7] 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 being melt-kneaded alone. [9] The intrinsic viscosity of the resin composition is 0.7 dL / g or more and 1.2 dL / g or less. A resin composition according to any one of the above [5] to [8], for use in bottles or sheets.

[10] The intrinsic viscosity of the resin composition is 0.4 dL / g or more and less than 0.7 dL / g, A resin composition according to any one of the above [5] to [9], for use in films or fibers.

[11] The intrinsic viscosity of the resin composition is 0.5 dL / g or more and 0.8 dL / g or less. A resin composition for injection molding, as described in any of the above [5] to

[10] .

[12] A resin molded article which is a molded product of any of the resin compositions described in [5] to

[11] above.

[13] The resin molded article described in

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

[14] A resin molded article as described in

[12] or

[13] above, wherein the degree of yellowness (YI value) as defined in JIS K7373 is less than 15.

[15] A resin molded article according to any of

[12] to

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

[16] A resin molded article according to any one of

[12] to

[14] above, which is a dry film resist support, an insert molding, or a release film. [Examples] 【0070】 One embodiment of the present invention will be described in detail below based on examples, but one embodiment of the present invention is not limited to these examples. 【0071】 <Preparing the materials> The following materials were prepared. The epoxy equivalent and weight-average molecular weight of the chain extender were measured using the following method. Furthermore, the weight-average number of epoxy functional groups of the chain extender was calculated using the weight-average molecular weight / epoxy equivalent ratio, using the measured epoxy equivalent and weight-average molecular weight. The intrinsic viscosity of the polyester resin (C) shown below is the value measured for the resin obtained by melt-kneading the polyester resin alone, and the measurement method will be described later. 【0072】 (Measurement of epoxy equivalent) The epoxy equivalent (g / mol) of the chain extender was determined by measurement in accordance with the provisions of JIS K7236. 【0073】 (Measurement of weight-average molecular weight) The weight-average molecular weight of the chain extender was measured by GPC using the following equipment and conditions. • GPC device: Product name "HLC-8020" (manufactured by Tosoh Corporation) • Columns: Product names "TSKgel G2000HXL", "G3000HXL", "G4000GXL" (manufactured by Tosoh Corporation) • Solvent: Tetrahydrofuran (THF) ·Flow rate: 1.0mL / min • Sample concentration: 2g / L ·Injection volume: 100μL ·Temperature: 40℃ • Detector: Model number "RI-8020" (manufactured by Tosoh Corporation) • Standard material: TSK standard polystyrene (manufactured by Tosoh Corporation) 【0074】 (Amorphous polyethylene terephthalate) • A-1: ​​Product name "EASTAR Copolyester GN071" (manufactured by Eastman Chemical Company, PET-G) 【0075】 (Chain elongator) • B-1: Product name "Joncryl ADR4468" (manufactured by BASF, "styrene / (meth)acrylate copolymer containing glycidyl groups", weight-average epoxy functional group count 23.4, weight-average molecular weight 7250, epoxy equivalent 310 g / mol) • B-2: Product name "Joncryl ADR4400" (manufactured by BASF, "styrene / (meth)acrylate copolymer containing glycidyl groups", weight-average epoxy functional group count 14.6, weight-average molecular weight 7100, epoxy equivalent 485 g / mol) • B-3: Product name "Modiper A4100" (manufactured by NOF Corporation, "styrene / (meth)acrylate copolymer containing glycidyl groups", weight-average epoxy functional group count 171.4, weight-average molecular weight 240,000, epoxy equivalent 1400 g / mol) • B-4: Product name "Marproof G-01100" (manufactured by NOF Corporation, "styrene / (meth)acrylate copolymer containing glycidyl groups", weight-average epoxy functional group count 70.5, weight-average molecular weight 12000, epoxy equivalent 170 g / mol) 【0076】 (Polyester resin (C)) • C-1: Product name "MA-2101M" (manufactured by Unitika Corporation, crystalline PET, intrinsic viscosity 0.60 dL / g) • C-2: The above polyester resin C-1 was melted and kneaded in a single-screw extruder (manufactured by Nippon Placon Co., Ltd., NS type 40mm vented extruder, L / D=30, screw diameter=40mm, 3-stage barrel, compression ratio 2.0) set to a rotation speed of 60 rpm and a barrel temperature of 280°C. The resulting material was extruded from a nozzle in the form of a string (strand), cooled in a water bath, and then cut in a pelletizer to form pellets. This process was repeated six times (crystalline PET, intrinsic viscosity 0.47 dL / g). • C-3: Product name "Kurapet KS710B-8S" (manufactured by Kuraray Co., Ltd., crystalline PET, intrinsic viscosity 0.96 dL / g) • C-4: Product name "SKYPURA0302" (manufactured by SK Chemical Co., Ltd., PCT, intrinsic viscosity 0.63 dL / g) • C-5: Product name "Panlite L-1250Y" (manufactured by Teijin, PC, intrinsic viscosity 1.08 dL / g) 【0077】 <Masterbatch Preparation> (Example 1-1) 80 parts by mass of amorphous PET resin A-1 and 20 parts by mass of chain extender B-1 were mixed using a small high-speed mixer to obtain a mixture. Next, this mixture was melt-kneaded in a twin-screw extruder (L / D=52.5, screw diameter=30mm) set to a rotation speed of 350 rpm and a barrel temperature of 200-240°C, and extruded from the nozzle in the form of strings (strands). After cooling the extruded strands in a water bath, they were cut in a pelletizer to produce a pellet-shaped masterbatch. 【0078】 (Examples 1-2 to 4, Comparative Examples 1-1 to 5) A masterbatch was prepared in the same manner as in Example 1-1 described above, except that the types of materials and the amounts used (in units of parts by mass) were as shown in the upper row of Table 1 (Tables 1-1 and 1-2). 【0079】 (Processability of masterbatch) The processability of the masterbatch was evaluated according to the evaluation criteria shown below. ○: The masterbatch has been created. ×: Masterbatch could not be produced. In Comparative Examples 1-1 and 1-6, the mixture gelled, and in Comparative Example 1-3, the mixture did not solidify, making it impossible to prepare a masterbatch. 【0080】 (Measurement of intrinsic viscosity) The intrinsic viscosity of each polyester resin (C) described above was measured according to the method specified in JIS K7367-5 for resins obtained by melt-kneading the polyester resin alone. Specifically, polyester resin (C) was melt-kneaded in a single-screw extruder (NS type 40 mm vented extruder, L / D=30, screw diameter=40 mm, 3-stage barrel, compression ratio 2.0, manufactured by Nippon Placon Co., Ltd.) set to a rotation speed of 60 rpm and a barrel temperature of 280°C. The resin was extruded from a nozzle in the form of a string (strand), cooled in a water bath, and then cut with a pelletizer to prepare pelletized resin. For polyester resin C-2, the above operation was repeated six times (6-pass sample) and used as the material. The obtained resin was dissolved in a mixed solvent of phenol and 1,1,2,2-tetrachloroethane (tetrachloroethane) in a mass ratio of 1:1, and the intrinsic viscosity of each polyester resin (C) was measured at 25°C using an Ostwald viscosity tube. 【0081】 The masterbatch that was prepared and its intrinsic viscosity (IV a Using polyester resin C-3, which is a crystalline PET with a viscosity of 0.96 dL / g, the intrinsic viscosity IV of the "resin composition sample" under the aforementioned condition (2) was bThe viscosity was measured. Specifically, the masterbatch and polyester resin C-3 were dry-blended in a ratio that resulted in a chain extender content of 0.4% by mass to obtain a mixture. Next, this mixture was melt-kneaded in a single-screw extruder (Nippon Placon Co., Ltd., NS type 40mm vented extruder, L / D=30, screw diameter=40mm, 3-stage barrel, compression ratio 2.0) set to a rotation speed of 60 rpm and a barrel temperature of 280°C, and extruded from the nozzle in the form of a string (strand). After cooling the extruded strand in a water bath, pelletized resin composition samples were prepared by cutting them with a pelletizer. The obtained resin composition samples were then measured in the same manner as above, according to the method specified in JIS K7367-5, to obtain an intrinsic viscosity of IV. b The following was measured. In the lower section of Table 1, IV a , IV b , IV b -IV a This shows the value. 【0082】 TIFF2026100510000001.tif4557 【0083】 TIFF2026100510000002.tif4573 【0084】 <Preparation of resin composition> (Example 2-1) 0.125 parts by mass of the masterbatch (MB1) prepared in Example 1-1 and 99.875 parts by mass of polyester resin C-1 were dry-blended to obtain a mixture. Next, this mixture was melt-kneaded in a single-screw extruder (NS type 40 mm vented extruder, manufactured by Nippon Placon Co., Ltd., set to a rotation speed of 60 rpm and a barrel temperature of 280°C, with a L / D ratio of 30, screw diameter of 40 mm, 3-stage barrel, and compression ratio of 2.0), and extruded from the nozzle in the form of a string (strand). After cooling the extruded strand in a water bath, the material was cut in a pelletizer to produce a pelletized resin composition. 【0085】 <Fabrication of resin molded products> The resin composition prepared in Example 2-1 was dried at 140°C for 4 hours. Then, a 1 mm thick plate was molded using an injection molding machine (NS-40 type molding machine, manufactured by Nissei Plastic Industrial Co., Ltd., with a clamping force of 40 t) under the conditions of cylinder temperature 280°C, injection pressure 60 MPa, and mold temperature 10°C. This was used as a test specimen for the resin molded body. 【0086】 (Examples 2-2 to 2-12, Comparative Examples 2-1 to 2-8) Pellet-shaped resin compositions and test specimens were prepared in the same manner as in Example 2-1 described above, except that the types of materials and amounts used (unit: parts by mass) were as shown in the upper row of Table 2 (Tables 2-1 to 2-3). In Comparative Example 2-8, a masterbatch was not used, and test specimens were prepared using only polyester resin (C). In Comparative Example 2-4, the viscosity during melting was too high, and the resin could not be filled into the mold during injection molding, resulting in failure to form the specimens. In Comparative Examples 2-2 and 2-8, the viscosity during melting was too low, causing the resin to leak out of the mold gaps and generate burrs. 【0087】 <Measurement and Evaluation Methods> (processability) When producing pelletized resin compositions using a single-screw extruder, the processability of the resin compositions was evaluated according to the evaluation criteria shown below by observing the state of the kneaded material extruded in strand form. The evaluation results are shown in the lower section of Table 2. AA: The strands could be processed in 10 minutes without breaking. A: The strand was cut once or twice in 10 minutes, but it was still machinable. B: The strand was cut 3 to 5 times in 10 minutes, but it was still machinable. C: The strand was severed more than 6 times in 10 minutes. 【0088】 The moldability of the resin composition was evaluated according to the evaluation criteria shown below, based on the molding conditions when forming test specimens from the resin composition using an injection molding machine. The evaluation results are shown in the lower section of Table 2. AA: Molding was possible under injection pressure conditions equivalent to those for molding polyester resin (C) alone (hereinafter referred to as "normal conditions"). A: Molding was possible by increasing the injection pressure by 5% from the normal conditions. B: Molding was possible by increasing the injection pressure from the normal conditions by more than 5% to 15% or less. C: Molding was not possible even when the injection pressure was increased to 15% from the normal conditions, or the viscosity during melting was low, causing resin to leak out from gaps in the mold and generate burrs. 【0089】 (Measurement of intrinsic viscosity of resin composition) For each pelletized resin composition prepared in Examples 2-1 to 2-12 and Comparative Examples 2-1 to 2-8, the intrinsic viscosity (IV) of the resin composition was measured in the same manner as described above, according to the method specified in JIS K7367-5. The results are shown in the lower section of Table 2. 【0090】 (transparency) A haze meter (manufactured by Suga Test Instruments Co., Ltd.) was used to measure the haze value of each test specimen according to JIS K7136. Based on the obtained haze values, the transparency of the test specimens was evaluated according to the evaluation criteria shown below. The results are shown in the lower section of Table 2. AA: The haze value was between 0% and 3%. A: The haze value was between 3% and 7%. B: The haze value was between 7% and 10%. C: The haze value was over 10%. 【0091】 (yellowness) Using a spectrophotometer (product name "CM-3600A", manufactured by Konica Minolta), each test specimen was measured for transmission under a D65 light source and a 10-degree field of view, and L * a * b * L in color systems * value, a * value, and b * The values ​​were measured. Then, the yellowness (YI value) was calculated in accordance with the provisions of JIS K7373, and the yellowness of the test specimens was evaluated according to the following evaluation criteria. The results are shown in the lower part of Table 2. The AA:YI value was less than 5. A: The YI value was between 5 and 10. B: The YI value was between 10 and 15. The C:YI value was 15 or higher. 【0092】 TIFF2026100510000003.tif6479 【0093】 TIFF2026100510000004.tif6451 【0094】 TIFF2026100510000005.tif6478 【0095】 (Application Example 1: T-die method) Using the same type and quantity of masterbatch and polyester resin as in Example 2-4, the mixture was uniformly mixed and then extruded at 280°C using a laboplast mill (manufactured by Toyo Seiki Co., Ltd.) 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 produced evaluation sample was pressed to produce a sheet with a thickness of approximately 20 μm. Visual inspection of the produced sheet confirmed that it had good transparency and low yellowness. 【0096】 (Application Example 2: Blow Molding Method) Using the same type and amount of masterbatch and polyester resin as in Example 2-4, a cylindrical bottle container with a capacity of 200 mL and a wall thickness of 1 mm was produced using a blow molding machine with a screw diameter of 40 mm heated to 280 °C. Visual inspection of the produced bottle container confirmed that it had good transparency and low yellowness. 【0097】 (Application Example 3: Melt Spinning Method) Using the same type and amount of masterbatch and polyester resin as in Example 2-6, the mixture was uniformly mixed and then extruded from the spinning pack using a φ30 mm melt spinning machine. The yarn was taken up at a draw speed of 2,500 m / min to obtain undrawn yarn. Subsequently, this undrawn yarn was heat-stretched four times to obtain fibers. There was no breakage of yarn during spinning, and visual inspection of a bundle of 50 fibers confirmed that yarn with low yellowness was obtained. 【0098】 (Application Example 4: Dry Film Resist Support) In Application Example 1, a biaxially oriented film with a thickness of 15 μm was produced using a biaxial stretching apparatus after extrusion from a T-die. This film was used as a base film, and a 10% by mass aqueous solution of polyvinyl alcohol was applied to one side of it using a gravure coater to form a release layer with a drying thickness of 2 μm. These were used as a dry film resist support. When the peel strength between the base film and the release layer of the support was measured, the peel strength was good. Furthermore, this support was transparent, and the coefficient of dynamic friction when the base film side and the release layer side were overlapped was low, indicating that it can be suitably used as a dry film resist support. 【0099】 (Application Example 5: Insert molding for membrane switches) Similar to Application Example 4, two biaxially oriented films with a thickness of 15 μm were prepared. These films were used as base films, and a circuit was screen printed on one side of one base film using silver paste. A spacer portion was printed on one side of the other base film using insulating paint. The printed surfaces of these films were then placed facing each other, the films were stacked, and bonded together to form a membrane switch. When the switching function of the resulting membrane switch was examined, it was found to be excellent in terms of transparency, flatness, and switching function, and was deemed suitable for use as a membrane switch. 【0100】 (Application example 6: Release film) A biaxially oriented film was prepared in the same manner as in Application Example 4, except that a solution of 5% by mass of ammonium zirconium carbonate, 15% by mass of polyoxyethylene nonylphenyl ether, and 80% by mass of stearyl alcohol was applied as a release layer using the kiss-coat method before transverse stretching. Further heat treatment at 200°C resulted in a release film with a thickness of 75 μm. As a release property test, a PVC emulsion was applied to the release layer side of the release film using a bar coater and heat-fused at 175°C to form a PVC film layer with a thickness of 50 μm. When the PVC film was peeled off the release layer, good release properties were confirmed, indicating that it can be suitably used as a release film.

Claims

[Claim 1] A masterbatch for polyester resin, Amorphous polyethylene terephthalate (A) and, A chain extender (B) having a weight-average epoxy functional group count of 2 or more and 70 or less, and a weight-average molecular weight of 100 or more and 100,000 or less, is contained in the above. A masterbatch in which the content of the chain extender (B) in the masterbatch is 2% by mass or more and 34% by mass or less, based on the total mass of the masterbatch. [Claim 2] A masterbatch according to claim 1 that satisfies the following conditions (1) to (2). Condition (1): Intrinsic viscosity IV after melting and kneading alone ａ The intrinsic viscosity of the resin composition sample obtained by melt-kneading crystalline polyethylene terephthalate having a concentration of 0.9 dL / g or more and 1.0 dL / g or less with the masterbatch in a proportion such that the chain extender (B) content is 0.4% by mass is IV ｂ When expressed as (dL / g), 0 < IV ｂ -IV ａ < 0.

29. Condition (2): The masterbatch is used by mixing it with the polyester resin under the condition that the content of the chain extender (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. [Claim 3] The masterbatch according to claim 1, wherein the amorphous polyethylene terephthalate (A) does not exhibit an exothermic peak associated with crystallization when it is melted by raising the temperature from 30°C to 300°C at 10°C / min and then solidified by lowering the temperature to 30°C at 10°C / min in differential scanning calorimetry. [Claim 4] The masterbatch according to claim 1, wherein the epoxy equivalent of the chain extender (B) is 100 g / mol or more and 1000 g / mol or less. [Claim 5] A resin composition comprising a masterbatch according to any one of claims 1 to 4 and a polyester resin (C). [Claim 6] The resin composition according to claim 5, wherein the polyester resin (C) comprises at least one selected from the group consisting of crystalline polyethylene terephthalate, crystalline polybutylene terephthalate, crystalline polycyclohexylene dimethylene terephthalate, crystalline polylactic acid, crystalline polyethylene terephthalate isophthalate, and crystalline polycarbonate. [Claim 7] The resin composition according to claim 5, wherein the polyester resin (C) comprises recycled polyethylene terephthalate. [Claim 8] The resin composition according to claim 5, wherein the polyester resin (C) comprises polyethylene terephthalate having an intrinsic viscosity of 0.4 dL / g or more and 1.3 dL / g or less after melt-kneading alone. [Claim 9] The intrinsic viscosity of the resin composition is 0.7 dL / g or more and 1.2 dL / g or less. The resin composition according to claim 5, for use in bottles or sheets. [Claim 10] The intrinsic viscosity of the resin composition is 0.4 dL / g or more and less than 0.7 dL / g. The resin composition according to claim 5, which is for use in films or fibers. [Claim 11] The intrinsic viscosity of the resin composition is 0.5 dL / g or more and 0.8 dL / g or less. The resin composition according to claim 5, for use in injection molding. [Claim 12] A resin molded article which is a molded product of the resin composition described in claim 5. [Claim 13] The resin molded article according to claim 12, wherein the haze value specified in JIS K7136 is 0% or more and 10% or less. [Claim 14] A resin molded article according to claim 12, wherein the degree of yellowness (YI value) as defined in JIS K7373 is less than 15. [Claim 15] The resin molded article according to claim 12, which is a food container, a non-food container, an injection molded article, a sheet, a film, a tape, or a fiber. [Claim 16] A resin molded article according to claim 11, which is a dry film resist support, an insert molding release film.