Masterbatch, Aromatic Polyester Resin Composition, Molded Body, and Methods for Producing the Same

Abstract

To provide a film composed of an aromatic polyester resin composition containing at least PBT resin, the aromatic polyester resin composition, and a method for producing the film, wherein it is possible to prevent a pressure rise in making a film from the resin composition while preventing the occurrence of defects in the film, and to suppress the progress of degradation of resin and enable stable film formation; and to further provide a master batch that can give the resin composition and a method for producing the same.SOLUTION: The present invention provides a master batch that contains, relative to 100 pts.mass of an aromatic polyester resin with an inherent viscosity of 0.5 or more to less than 0.9, less than 15 pts.mass of fine particles with an average particle size of 0.5-10 μm, and a method for producing the same. There are also provided an aromatic polyester resin composition for films including the master batch, and a method for producing films.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a masterbatch containing polybutylene terephthalate (hereinafter also referred to as "PBT"), a resin composition containing an aromatic polyester, a molded article, and methods for producing them. More specifically, the present invention relates to a method for producing an aromatic polyester resin composition for a film, a masterbatch used therefor and a method for producing the same, and further to a method for producing a film using the aromatic polyester resin composition for a film.

Background Art

[0002] Since PBT resin is excellent in various properties such as ease of molding, mechanical properties, heat resistance, and chemical resistance, it is widely used in various applications. In recent years, taking advantage of gas barrier properties and the like, it has also begun to be developed for film and sheet applications.

[0003] However, the film has low slipperiness, and when wound into a roll, the films adhere to each other, making it difficult to pull out the film. Moreover, if pulled out forcibly, there are problems such as the formation of scratches and wrinkles.

[0004] For this reason, a method has been adopted in which fine particles are added to form irregularities on the film surface to improve the slipperiness of the film (see Cited Document 1). However, when using fine particles, there is a high tendency for poor dispersion to occur, particularly in the masterbatch where the fine particles are present at a high concentration. As a result, not only the occurrence of film defects and the increase in filter pressure during film formation occur, but also resin deterioration progresses, making stable film formation difficult.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, the problems to be solved by the present invention are as follows: a film made of an aromatic polyester resin composition containing at least PBT resin, while suppressing the occurrence of film defects, suppressing the pressure increase of the filter when forming a film from the resin composition, further suppressing the progress of resin deterioration, enabling stable film formation, providing an aromatic polyester resin composition and a method for producing a film, and providing a masterbatch and a method for producing the same that can provide such an aromatic polyester resin composition for a film.

Means for Solving the Problems

[0007] To solve the above problems, as a result of intensive research by the inventors, by making the viscosity of the PBT resin in the masterbatch appropriate, particle aggregation, which is a film defect in the film produced using it, is eliminated, and it has been found that resin deterioration that causes deterioration of film formability is suppressed, leading to the solution of the present invention.

[0008] That is, the present invention provides the following inventions. 〔1〕Regarding a masterbatch (1) characterized in that it contains fine particles (b) having an average particle diameter of 0.5 to 10 μm in an amount of less than 15 parts by mass with respect to 100 parts by mass of a polybutylene terephthalate resin (a) having an intrinsic viscosity of 0.5 or more and less than 0.9.

[0009] 〔2〕The present invention also relates to a method for producing a masterbatch, characterized in that it has a step of blending fine particles (b) having an average particle diameter of 0.5 to 10 μm in an amount of less than 15 parts by mass with respect to 100 parts by mass of a polybutylene terephthalate resin (a) having an intrinsic viscosity of 0.5 or more and less than 0.9 and melt-kneading them.

[0010] 〔3〕Furthermore, the present invention is a method for producing an aromatic polyester resin composition exclusively used for films, Regarding a method for producing an aromatic polyester polybutylene terephthalate resin composition, which comprises a step of blending an aromatic polyester polybutylene terephthalate resin (c) with the masterbatch described in [1] and melt-kneading them.

[0011] 〔4〕Furthermore, the present invention relates to a method for producing a film, which comprises a step of melt-molding the aromatic polyester polybutylene terephthalate resin composition obtained by the production method described in [3].

[0012] 〔5〕Furthermore, the present invention relates to a method for producing a film, which comprises a step of blending an aromatic polyester polybutylene terephthalate resin (c) with the masterbatch described in [1] and melt-kneading them, and a step of melt-molding.

Effects of the Invention

[0013] According to the present invention, there are provided an aromatic polyester resin composition and a method for producing a film, which are composed of a film made of an aromatic polyester resin composition containing at least a PBT resin, suppress the occurrence of film defects, suppress the pressure increase of a filter when forming a film from the resin composition, further suppress the progress of resin deterioration, and enable stable film formation, and a masterbatch and a method for producing the same, which can provide such an aromatic polyester resin composition for a film.

Modes for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments.

[0015] <Masterbatch> The masterbatch of the present embodiment is characterized in that it contains fine particles (b) having an average particle diameter of 0.5 to 10 μm in an amount of less than 15 parts by mass with respect to 100 parts by mass of a polybutylene terephthalate resin (a) having an intrinsic viscosity of 0.5 or more and less than 0.9. The method for manufacturing the masterbatch of the present embodiment is characterized by having a step of melt-kneading by blending fine particles (b) having an average particle diameter of 0.5 to 10 μm in an amount of less than 15 parts by mass with respect to 100 parts by mass of a polybutylene terephthalate resin (a) having an intrinsic viscosity of 0.5 or more and less than 0.9.

[0016] [PBT resin (a)] The PBT resin (a) used in the present invention has an intrinsic viscosity in the range of 0.5 or more, preferably 0.6 or more, and less than 0.9, preferably 0.8 or less, because particle aggregation, which causes film defects, is eliminated and deterioration of the resin that causes deterioration of film-forming properties during film production can be suppressed.

[0017] The PBT resin used in the present invention has a structure in which terephthalic acid units and 1,4-butanediol (hereinafter sometimes abbreviated as BG) units are ester-bonded, and is a polymer in which 50 mol% or more of the dicarboxylic acid units are composed of terephthalic acid units and 50 mol% or more of the diol component is composed of BG units.

[0018] Here, the ratio of terephthalic acid units in all dicarboxylic acid units is preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 95 mol% or more, and the ratio of BG units in all diol units is preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 95 mol% or more.

[0019] In the present invention, the dicarboxylic acid component other than terephthalic acid is not particularly limited. For example, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 2,6-naphthalenedicarboxylic acid; alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid; aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc. can be mentioned. These dicarboxylic acid components can be introduced into the polymer backbone as dicarboxylic acids or using dicarboxylic acid derivatives such as dicarboxylic acid esters and dicarboxylic acid halides as raw materials.

[0020] In the present invention, the diol component other than BG is not particularly limited. For example, aliphatic diols such as ethylene glycol, diethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, polypropylene glycol, polytetramethylene glycol, dibutylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol; alicyclic diols such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol; aromatic diols such as xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)sulfone, etc. can be mentioned.

[0021] [Fine particles (b)] The fine particles (b) used in the present invention have an average particle diameter of 0.5 μm or more, preferably in the range of 1.0 μm or more from the viewpoint of slipperiness, and 10 μm or less, and in the range of 8.0 μm or less from the viewpoint of transparency. The fine particles used in the present invention are not particularly limited. Examples include silicates such as wollastonite, sericite, kaolin, mica, clay, bentonite, asbestos, talc, and aluminosilicate; metal oxides such as alumina, silicon chloride, magnesium oxide, zirconium oxide, and titanium oxide; carbonates such as calcium carbonate, magnesium carbonate, and dolomite; sulfates such as calcium sulfate and barium sulfate; inorganic fine particles such as glass beads, boron nitride, silicon carbide, and silica. These may be hollow. One or a combination of two or more of these can be used. Among these, from the viewpoint of imparting slipperiness to the film and having better transparency, silica and aluminosilicate are preferably mentioned.

[0022] In addition, the surface of the fine particles used in the present invention may be hydrophobic or hydrophilic. However, since the transparency of the finally obtained film becomes even better, it is more preferably hydrophilic. The hydrophobicity or hydrophilicity of the surface of the fine particles used in the present invention may be subjected to known hydrophobic treatment or hydrophilic treatment as necessary. If the fine particles themselves exhibit the desired hydrophobicity or hydrophilicity, they can be used without treatment.

[0023] Incidentally, the degree of hydrophobicity or hydrophilicity of the surface of the fine particles used in the present invention can be represented, for example, by the DBA adsorption amount. In the case of hydrophobicity, the DBA adsorption amount is preferably in the range of less than 300 meq / kg, while in the case of hydrophilicity, the DBA adsorption amount is preferably in the range of 400 meq / kg or more. However, the DBA adsorption amount can be measured by the method of the examples.

[0024] Examples of the fine particles that can be preferably used in the present invention include, for example, silica (silicon dioxide) fine particles "SYLOPHOBIC" series manufactured by Fuji Silysia Chemical Ltd., which are fine particles having a hydrophobic surface. On the other hand, silica "SYLYSIA" series manufactured by Fuji Silysia Chemical Ltd., silica fine particles "SEAHOSTAR" series manufactured by Nippon Shokubai Co., Ltd., and alumina silicate (aluminosilicate) fine particles "SILTON" series manufactured by Mizusawa Chemical Industry Co., Ltd. are mentioned as fine particles having a hydrophilic surface.

[0025] The ratio of the PBT resin (a) to the fine particles (b) in the masterbatch is such that, based on 100 parts by mass of the PBT resin (a), the aggregation of the particles is eliminated, and from the viewpoint of deterioration of film-forming properties, the fine particles (b) are less than 15 parts by mass, preferably 10 parts by mass or less. The lower limit is not limited, but from the viewpoint of the efficiency of the masterbatch, it is preferably 0.1 part by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more.

[0026] [Other components] The masterbatch may contain other components as optional components within the range that does not deviate from the main purpose of its function, in addition to the above-mentioned PBT resin (a) and the above-mentioned fine particles (b) which are essential components. Specific examples of other components include antioxidants, ultraviolet absorbers, colorants, pigments, dyes, foaming agents, lubricants, flame retardants, fillers, etc. When other components are used as optional components, the blending ratio is not particularly limited as long as the effects of the present invention are not impaired, but it is preferably used in the range of 50 parts by mass or less, more preferably 25 parts by mass or less, based on 100 parts by mass of the PBT resin (a). By adjusting the type and amount of these components, the desired function can be freely adjusted.

[0027] <Manufacturing method of masterbatch> The manufacturing method of the masterbatch of the present invention includes a step of blending and melt-kneading the above-mentioned PBT resin (a) and the above-mentioned fine particles (b) (hereinafter sometimes referred to as "step (1)").

[0028] First, the essential components of the PBT resin (a) and the fine particles (b), and the other components which are optional raw material components as required, are compounded in various forms such as bulk form, pellet form, chip form, etc. to have a predetermined compounding ratio. Then, after pre-mixing as required, it is put into a melt kneader and heated to a temperature equal to or higher than the melting point of the PBT resin (a) for melt kneading. The form of the melt kneaded product is not particularly limited as long as the effects of the present invention are not impaired. It is also possible to directly add the dilution resin described below to form the thermoplastic resin composition or molded article of the present invention while in a molten state. However, it is preferably granulated into pellet form, chip form, etc. after being once extruded into strand form and then cut.

[0029] In the step (1), the pre-mixing is not particularly limited as long as the effects of the present invention are not impaired, and examples thereof include dry blending using a ribbon blender, Henschel mixer, V blender, etc. Also, the melt kneader is not particularly limited as long as the effects of the present invention are not impaired, and examples thereof include a melt kneader equipped with a heating mechanism such as a Banbury mixer, mixing roll, single-screw or twin-screw extruder, and kneader. Incidentally, the melt kneader in the above step may be loaded with a filter having an opening size in the range of preferably 100 μm or less, more preferably 50 μm or less, and still more preferably 30 μm or less in the apparatus.

[0030] The intrinsic viscosity of the masterbatch of the present invention thus obtained is not particularly limited, but is preferably 0.6 or more and preferably 0.9 or less.

[0031] <Aromatic polyester resin composition and its molded article (film)> The method for producing the aromatic polyester resin composition and the molded article (film) of the present invention includes a step of blending the masterbatch and an aromatic polyester resin (c) as a diluting resin and performing melt-kneading (hereinafter, sometimes referred to as "step (2)"). The aromatic polyester resin composition or the molded article is a cured product (a product in which a state softened and fluidized by heating is solidified by cooling) obtained by blending the above masterbatch and the aromatic polyester resin (c). The aromatic polyester resin composition is not particularly limited, but for example, it is an intermediate molded article when obtaining a film from the masterbatch, and means a material having a predetermined form such as pellet form or powder form.

[0032] [Aromatic polyester resin (c)] The aromatic polyester resin (c) used in the present invention is used as a diluting resin for the masterbatch. The aromatic polyester resin (c) used in the present invention is not particularly limited, and examples thereof include polyethylene terephthalate (PET), polypropylene terephthalate, polybutylene terephthalate (PBT), polyhexylene terephthalate, polycyclohexylene dimethylene terephthalate (PCT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), polycyclohexane dimethyl phthalate (PCN), polytrimethylene naphthalate (PTN), amorphous polyester resins (PETG, PCTG), polyethylene-1,2-bis(phenoxy)ethane-4,4'-dicarboxylate, polyethylene isophthalate / terephthalate, polybutylene terephthalate / isophthalate, and the like. Further, one selected from among these polyester resins may be used alone, or two or more thereof may be used in combination.

[0033] Among these, as the aromatic polyester resin (c), the same resins as the PBT resin (a) listed above can be used. When using the same PBT resin as the PBT resin (a) listed above for the PBT resin (c), it may be the same type as the PBT resin (a) contained in the masterbatch or a different type, but it is preferable to use the same type of resin from the viewpoint of compatibility.

[0034] The blending ratio of the masterbatch and the aromatic polyester resin (c) is such that, when the total mass of the masterbatch and the aromatic polyester resin (c) in the aromatic polyester resin composition or film is 100% by mass, the content ratio of the fine particles (b) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and preferably 3% by mass or less, more preferably 1.5% by mass or less, still more preferably 1% by mass or less, and can be appropriately adjusted within this range. [Other Components] The aromatic polyester resin composition or film may contain other components as optional components in addition to the masterbatch and the aromatic polyester resin (c) which are essential components, as long as the main purpose of its function is not deviated from. Specific examples of other components include antioxidants, ultraviolet absorbers, colorants, pigments, dyes, foaming agents, lubricants, flame retardants, fillers, and the like.

[0035] <Method for Producing Aromatic Polyester Resin Composition and Film> The method for producing the aromatic polyester resin composition or film according to the present embodiment involves blending the masterbatch obtained by the above production method, the essential component of the aromatic polyester resin (c), and other components that are optional components as needed, in various forms such as bulk, pellet, chip, etc., to achieve a predetermined blending ratio. Then, after preliminary mixing as needed, it is fed into a melt kneader and heated to a temperature equal to or higher than the higher melting point of either the PBT resin (a) or the aromatic polyester resin (c), followed by melt kneading. As a result, the above film can be directly obtained by melt molding. However, it is also possible to obtain the target film through a process of first obtaining a pelletized or powdered aromatic polyester resin composition and then subjecting the obtained pelletized or powdered aromatic polyester resin composition to a melt molding process. By obtaining the film via the masterbatch in this way, fine particles can be more stably and uniformly dispersed in the film, and the desired functions and properties due to the fine particles can be sufficiently imparted to the film. Further, by forming the film through the above masterbatch, hydrolysis of the aromatic polyester resin can be significantly suppressed, and the moldability (processability), mechanical properties, and appearance quality can be improved.

[0036] When the thermoplastic resin composition of the present invention is made into a film, after melt kneading, the molten resin can be discharged (extruded) from slit-shaped holes to form a film or sheet. The film or sheet-shaped thermoplastic resin molded body (film) may be further molded by a press molding method or a vacuum molding method, or may be formed on a base layer to constitute a multilayer film. In the present invention, the film refers to a film-like or sheet-like thermoplastic resin molded body, and furthermore, it is expressed as a general term without strictly distinguishing between plate-like objects such as films and sheets. In the present invention, the thickness of the film varies depending on its use and can be any thickness, but usually, preferably 0.01 μm or more, more preferably 0.05 μm or more, still more preferably 0.1 μm or more, particularly preferably 0.3 μm or more, most preferably 0.5 μm or more, and preferably 1 mm or less, more preferably 500 μm or less, still more preferably 150 μm or less, particularly preferably 100 μm or less, and most preferably 70 μm or less.

Example

[0037] Hereinafter, examples of the present invention will be described. The present invention is not limited to the examples shown below. In the examples, unless otherwise specified, "parts" indicates mass %, and the units of the numerical values in the table are parts by mass.

[0038] (Measurement Example) Intrinsic viscosity The intrinsic viscosity of the PBT resin is a value measured at a temperature of 23°C after dissolving the PBT resin using an octochlorophenol solution.

[0039] (Measurement Example) DBA adsorption amount Precisely weigh 250 mg of the dried sample, add 50 ml of an N / 500 - di-n-butylamine solution (petroleum benzine solvent) thereto, and leave it standing at 20°C for about 2 hours. Add 5 ml of chloroform and 2 - 3 drops of an indicator (crystal violet) to 25 ml of this supernatant, and titrate with an N / 100 - perchloric acid solution (anhydrous acetic acid solvent) until the purple color changes to blue. Let the titration value at this time be A ml. Separately, perform a blank and set it as B ml, and calculate the DBA adsorption amount according to the following formula.

[0040]

Number

[0041] (Measurement Example) Resin Degradation (Retention Rate of Intrinsic Viscosity) The retention rate of the intrinsic viscosity was calculated to evaluate the resin degradation state. The closer the retention rate is to 100%, the better it indicates that the resin degradation is suppressed.

[0042]

Number

[0043] (Measurement Example) Filter Pressure Rise of Masterbatch (MB) The differential pressure (filter pressure rise) when 1 kg of masterbatch was passed through a single-screw extruder equipped with a 20-μm aperture filter was measured, and the agglomeration of particles was evaluated according to the following criteria. Note that the larger the differential pressure, the more the amount of agglomerated particles present. ◎ ··· Less than 0.5 MPa 〇 ··· 0.5 MPa or more and less than 2 MPa △ ··· 2 MPa or more and less than 5 MPa × ··· 5 MPa or more

[0044] (Measurement Example) Agglomerated Particles in Film The prepared film was observed with an optical microscope, and the amount of agglomerated particles of 15 μm or more present per 100 cm 2 was evaluated according to the following criteria. ◎ ··· Less than 5 particles 〇 ··· 5 particles or more and less than 10 particles △ ··· 10 particles or more and less than 20 particles × ··· 20 particles or more

[0045] (Measurement Example) Film Forming Property The stability during film formation was evaluated according to the following criteria. 〇 ··· The state of the discharged material was stable, and film formation was completed without problems △ ··· Some viscosity reduction, pulsation phenomenon, fluctuation of the discharge width, foaming, etc. of the discharged material were observed, but film formation was completed × ··· A stable film could not be ensured due to viscosity reduction, pulsation phenomenon, fluctuation of the discharge width, foaming, etc. of the discharged material

[0046] Examples 1 - 6, Comparative Examples 1 - 2 (Manufacture of Masterbatch) The PBT resin and the fine particles were blended at the compounding ratios shown in Table 1, dry blended, and then melt kneaded using a 30 mmφ twin - screw extruder (set temperature: 260°C). The resulting composition was pelletized to obtain a masterbatch.

[0047]

Table 1

[0048]

Table 2

[0049] The numerical values in the table are based on mass, and the following were used for each component. PBT - 1; PBT resin "DURANEX 200FP" (intrinsic viscosity 0.6 dl / g) manufactured by Polyplastics Co., Ltd. PBT - 2; PBT resin "DURANEX 500FP" (intrinsic viscosity 0.8 dl / g) manufactured by Polyplastics Co., Ltd. PBT - c1; PBT resin "DURANEX 600FP" (intrinsic viscosity 1.0 dl / g) manufactured by Polyplastics Co., Ltd. FP - 1; Silica fine particles ("SYLYSIA (registered trademark) 550" manufactured by Fuji Silysia Chemical Ltd., average particle diameter 3.9 μm, DBA adsorption amount 800 meq / kg) FP - 2 Aluminosilicate fine particles ("SILTON (registered trademark) JC - 50" manufactured by Mizusawa Chemical Industry Co., Ltd., average particle diameter 4.9 μm) FP - 3; Silica fine particles ("SYLOPHOBIC (registered trademark) 505" manufactured by Fuji Silysia Chemical Ltd., average particle diameter 3.9 μm, DBA adsorption amount 175 meq / kg)

[0050] Examples 7 - 12, Comparative Examples 3 - 4 (Manufacture of Film) The PBT resin (Polyplastics Co., Ltd.'s "DURANEX 300FP", intrinsic viscosity 0.7) and the masterbatches (MB(1) to (4), MB(c1) to (c2)) were mixed in a predetermined amount so that the fine particle concentration in the film became 0.3 wt%, and dried at 120 °C for 12 hours. Then, using an extruder connected with a 100 mm wide T-die, film formation was carried out at a film formation temperature of 260 °C to obtain a film with a thickness of 30 μm. Each measurement was performed on the obtained film and described in Tables 3 and 4.

[0051]

Table 3

[0052]

Table 4

[0053] It was found that the films of Examples 7 to 12 obtained via the masterbatches manufactured in Examples 1 to 6 had no particle aggregation, which is a film defect, due to the optimal intrinsic viscosity of the PBT resin used in the preparation of the masterbatch, and resin deterioration that causes deterioration of film formability during film formation was suppressed. On the other hand, the films of Comparative Examples 3 and 4 obtained via the masterbatches manufactured in Comparative Examples 1 and 2 could not eliminate particle aggregation in the masterbatch, causing the occurrence of film defects and an increase in the filter pressure during film formation. Also, due to the progress of resin deterioration, it became clear that film formation deteriorated during film formation.

Claims

1. A method for producing a masterbatch, comprising a step of melt-kneading by blending, in a range of less than 15 parts by mass, fine particles (b) having a hydrophilic surface and an average particle diameter of 0.5 to 10 μm with a DBA adsorption amount of 400 meq / kg or more, based on 100 parts by mass of a polybutylene terephthalate resin (a) having an inherent viscosity of 0.5 or more and less than 0.

9.

2. The method for producing a masterbatch according to claim 1, wherein the fine particles (b) are silica.

3. A method for producing an aromatic polyester resin composition exclusively used for films, comprising: a step of melt-kneading by blending an aromatic polyester (c) with the masterbatch obtained by the production method according to claim 1.

4. A method for producing a film, comprising a step of melt-molding the aromatic polyester resin composition obtained by the production method according to claim 3.

5. A method for producing a film, comprising a step of melt-kneading by blending an aromatic polyester resin (c) with the masterbatch obtained by the production method according to claim 1, and a step of melt-molding.

6. The method for producing a masterbatch according to claim 1, wherein after the step of melt-kneading, the masterbatch is made into granules.

7. The method for producing an aromatic polyester resin composition according to claim 3, wherein when the total mass of the masterbatch and the aromatic polyester resin (c) is 100% by mass, the content ratio of the fine particles (b) is 0.01% by mass or more and 3% by mass or less.

8. The method for producing a masterbatch according to claim 1, wherein the terephthalic acid unit accounts for 95 mol% or more of all the dicarboxylic acid units of the polybutylene terephthalate resin (a).

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